Polyester resin and molded product containing the same

Abstract

To provide a polyester resin that achieves high Tg and low water absorption and a molded product.SOLUTION: A polyester resin containing at least one of the structural units represented by general formula (A), the structural units represented by general formula (B), and the structural units represented by general formula (C). In the formula, R1 is a linear aliphatic hydrocarbon group with 6 or more carbon atoms, R3 is a branched alkyl group with 3 or more carbon atoms, R2 and R4 are H or substituents, R5 is an aliphatic hydrocarbon group, X is a hydrocarbon group with a cyclic structure, n is an integer from 0 to 8, m is an integer from 1 to 4, and * indicates a bonding site.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a polyester resin and a molded article containing the same. [Background technology]

[0002] Polyester resins are excellent in heat resistance, mechanical strength, low water absorption, and the like, and are therefore widely used in a wide range of fields, including synthetic fibers, films, and PET bottles, as well as machine parts, automobile parts, containers, and electronic materials. Polyesters having specific chemical structures have been extensively studied for these applications.

[0003] For example, Patent Document 1 discloses a polyester containing at least one of structural units derived from bisphenol having a branched alkyl group with 4 or more carbon atoms and structural units derived from bisphenol having a linear alkyl group with 3 to 21 carbon atoms in a total content of 10% by mass or more, and containing 10% by mass or more of structural units derived from dicarboxylic acid having a biphenyl structure. Patent Document 2 describes a polyester resin containing a structure derived from an ortho-substituted bisphenol compound, and describes a method for producing a charge transport layer in an electrophotographic photoreceptor by using this polyester resin as a binder resin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2022 / 239656 [Patent Document 2] JP 2003-029447 A Summary of the Invention [Problem to be solved by the invention]

[0005] Applications of polyester resins include electrical insulating materials that utilize their heat resistance and low water absorption. However, research by the present inventors has revealed that conventional polyester resins such as those described in Patent Documents 1 and 2 above have not yet achieved a high level of compatibility between a high glass transition temperature (hereinafter, glass transition temperature is also referred to as "Tg") and low water absorption. That is, the examples of Patent Document 1 show that a cast film formed from a polyester containing either one of a structural unit derived from a bisphenol having a branched alkyl group with 4 or more carbon atoms or a structural unit derived from a bisphenol having a linear alkyl group with 3 to 21 carbon atoms and a structural unit derived from a dicarboxylic acid having a biphenyl structure at a specific content ratio is excellent in abrasion resistance and excellent in film formability even when a large amount of functional material is coexisted. In other words, the polyester described in Patent Document 1 only describes a form using either one of a structural unit derived from a bisphenol having a branched alkyl group with 4 or more carbon atoms or a structural unit derived from a bisphenol having a linear alkyl group with 3 to 21 carbon atoms, and as a result, it does not realize both high Tg and low water absorption at a high level. Furthermore, Patent Document 2 does not describe properties such as high Tg and low water absorbency, and the polyester having a structural unit derived from a bisphenol having a branched alkyl group described in the examples of Patent Document 2 does not achieve both high Tg and low water absorbency at a desired high level. That is, the polyester described in Examples 8 and 11 of Patent Document 2 is a polyester having a bisphenol component having a branched alkyl group and a structural unit derived from a bis(4-hydroxy-3,5-dimethylphenyl)methane component that does not contribute to low water absorbency, and is even inferior in low water absorbency to a polyester whose bisphenol component is only a bisphenol having a branched alkyl group (see polyester c2 described in the examples below).

[0006] An object of the present invention is to provide a polyester resin that achieves both a high Tg (120° C. or higher) and low water absorption (water absorption rate of less than 0.30% by mass), and a molded article containing the same. [Means for solving the problem]

[0007] The above-mentioned problems of the present invention have been solved by the following means. <1> A polyester resin comprising a structural unit represented by the following general formula (A) and at least one of a structural unit represented by the following general formula (B) and a structural unit represented by the following general formula (C): [ka] In the above formula, R 1 represents a linear aliphatic hydrocarbon group having 6 or more carbon atoms, and R 2 represents a hydrogen atom, an aliphatic hydrocarbon group, or an aromatic hydrocarbon group. 1 and R 2 are not bonded to form a ring. X represents a hydrocarbon group having a cyclic structure. * indicates a bond. [ka] In the above formula, R 3 represents a branched alkyl group having 3 or more carbon atoms, and R 4 represents a hydrogen atom or an aliphatic hydrocarbon group having 1 to 5 carbon atoms. 3 and R 4 are not bonded to form a ring. X represents a hydrocarbon group having a cyclic structure. * indicates a bond. [ka] In the above formula, R 5 represents an aliphatic hydrocarbon group, and X represents a hydrocarbon group having a cyclic structure. n is an integer of 0 to 8, and m is an integer of 1 to 4. * indicates a bond. The 1,4-phenylene group in the above general formulas (A) to (C) may have an aliphatic hydrocarbon group and / or an aromatic hydrocarbon group as a substituent. <2> wherein X is an arylene group; <1> The polyester resin according to claim 1, <3> Contains at least a structural unit represented by the general formula (A) and a structural unit represented by the general formula (B), <1> or <2> The polyester resin according to claim 1, <4> <1> ~ <3> 1. A molded article comprising the polyester resin according to any one of claims 1 to 9.

[0008] In the present invention, when there are a plurality of substituents or linking groups, etc., represented by a specific symbol or formula (hereinafter referred to as substituents, etc.), or when a plurality of substituents, etc., are specified at the same time, unless otherwise specified, the respective substituents, etc. may be the same or different from each other (regardless of the presence or absence of the expression "independently each", the respective substituents, etc. may be the same or different from each other). This also applies to the definition of the number of substituents, etc. In addition, in the present invention, when there are a plurality of structural units represented by a specific formula, unless otherwise specified, the respective structural units may be the same or different from each other (regardless of the presence or absence of the expression "independently each", the respective structural units may be the same or different from each other). In addition, when a plurality of substituents, etc., are adjacent to each other (particularly, when adjacent), they may be linked to each other to form a ring, unless otherwise specified. In addition, unless otherwise specified, a ring, for example, an alicyclic ring, an aromatic ring, or a heterocyclic ring may be further condensed to form a condensed ring. In the present invention, unless otherwise specified, when a double bond exists in a molecule in the form of an E or Z, the double bond may be either of them or a mixture thereof. In the present invention, unless otherwise specified, when a compound has one or more asymmetric carbons, the stereochemistry of such asymmetric carbons can be either the (R) or (S) form, independently of one another. As a result, the compound may be a mixture of stereoisomers, such as optical isomers or diastereoisomers, or may be a racemate. In the present invention, the description of the compounds includes those in which the structure is partially modified as long as the effect of the present invention is not impaired. Furthermore, compounds that are not specified as substituted or unsubstituted may have any substituent as long as the effect of the present invention is not impaired. In the present invention, when the number of carbon atoms in a certain group is specified, this number of carbon atoms means the number of carbon atoms in the entire group, unless otherwise specified in the present invention or this specification. In the present invention, a numerical range expressed using "to" means a range including the numerical values ​​before and after "to" as the lower and upper limits.

[0009] In the present invention, the aliphatic hydrocarbon group is a monovalent group obtained by removing any one hydrogen atom from an aliphatic hydrocarbon. Preferably, it is a monovalent group obtained by removing any one hydrogen atom from an aliphatic hydrocarbon, such as an alkane, alkene, alkyne, cycloalkane, cycloalkene, or cycloalkyne. The aliphatic hydrocarbon group may be linear or branched, and may have a ring structure. That is, preferred examples of the aliphatic hydrocarbon group include an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, a cycloalkenyl group and a cycloalkynyl group. A straight-chain aliphatic hydrocarbon group is a group in which one hydrogen atom has been removed from the terminal carbon atom of a straight-chain aliphatic hydrocarbon. Preferred examples of the straight-chain aliphatic hydrocarbon group include a straight-chain alkyl group, a straight-chain alkenyl group, and a straight-chain alkynyl group.

[0010] In the present invention, the alkyl group preferably has 1 to 24 carbon atoms, more preferably 1 to 19 carbon atoms, further preferably 1 to 15 carbon atoms, and particularly preferably 1 to 11 carbon atoms. Examples of straight-chain alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n-icosyl, n-henicosyl, n-docosyl, n-tricosyl, and n-tetracosyl groups. Examples of branched alkyl groups include methylethyl, methylpropyl, methylbutyl, methylpentyl, methylhexyl, methylheptyl, methyloctyl, methylnonyl, methyldecyl, methylundecyl, methyldodecyl, methyltridecyl, methyltetradecyl, methylpentadecyl, methylhexadecyl, methylheptadecyl, methyloctadecyl, methylnonadecyl, methylicosyl, methylhenicosyl, methyldocosyl, methyltricosyl, and the like. Dimethylethyl group, dimethylpropyl group, dimethylbutyl group, dimethylpentyl group, dimethylhexyl group, dimethylheptyl group, dimethyloctyl group, dimethylnonyl group, dimethyldecyl, dimethylundecyl group, dimethyldodecyl group, dimethyltridecyl group, dimethyltetradecyl group, dimethylpentadecyl group, dimethylhexadecyl group, dimethylheptadecyl group, dimethyloctadecyl group, dimethylnonadecyl group, dimethylicosyl group, dimethylhenicosyl group, dimethyldocosyl group, trimethylethyl group, trimethylpropyl group, trimethylbutyl group, trimethylpentyl group, trimethylhexyl group, trimethylheptyl group, trimethyloctyl group, trimethylnonyl group, trimethyldecyl group, trimethylundecyl group, trimethyldodecyl group, trimethyltridecyl group, trimethyltetradecyl group, trimethylpentadecyl group, trimethylhexadecyl group, trimethylheptadecyl group, trimethyloctadecyl group, trimethylnonadecyl group, trimethylicosyl group, trimethylhenicosyl group, Ethylethyl group, ethylpropyl group, ethylbutyl group, ethylpentyl group, ethylhexyl group, ethylheptyl group, ethyloctyl group, ethylnonyl group, ethyldecyl group, ethylundecyl group, ethyldodecyl group, ethyltridecyl group, ethyltetradecyl group, ethylpentadecyl group, ethylhexadecyl group, ethylheptadecyl group, ethyloctadecyl group, ethylnonadecyl group, ethylicosyl group, ethylhenicosyl group, ethyldocosyl group, Propylpropyl group, propylbutyl group, propylpentyl group, propylhexyl group, propylheptyl group, propyloctyl group, propylnonyl group, propyldecyl group, propylundecyl group, propyldodecyl group, propyltridecyl group, propyltetradecyl group, propylpentadecyl group, propylhexadecyl group, propylheptadecyl group, propyloctadecyl group, propylnonadecyl group, propylicosyl group, propylhenicosyl group, Examples of such groups include a butylbutyl group, a butylpentyl group, a butylhexyl group, a butylheptyl group, a butyloctyl group, a butylnonyl group, a butyldecyl group, a butylundecyl group, a butyldodecyl group, a butyltridecyl group, a butyltetradecyl group, a butylpentadecyl group, a butylhexadecyl group, a butylheptadecyl group, a butyloctadecyl group, a butylnonadecyl group, and a butylicosyl group. In the above examples of branched alkyl groups, the branching position is optional.

[0011] In the present invention, the alkenyl group preferably has 2 to 24 carbon atoms, more preferably 2 to 19 carbon atoms, further preferably 2 to 15 carbon atoms, and particularly preferably 2 to 11 carbon atoms. Examples of alkenyl groups include vinyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, octadecenyl, nonadecenyl, icosenyl, henicosenyl, docosenyl, tricosenyl, tetracosenyl, and 4,8,12-trimethyltridecyl groups.

[0012] In the present invention, the alkynyl group preferably has 2 to 24 carbon atoms, more preferably 2 to 19 carbon atoms, further preferably 2 to 15 carbon atoms, and particularly preferably 2 to 11 carbon atoms. Examples of the alkynyl group include an ethynyl group and a propynyl group.

[0013] In the present invention, the cycloalkyl group is a monovalent group obtained by removing any one hydrogen atom from a cycloalkane. The cycloalkyl group is preferably a cycloalkyl group having 3 to 24 carbon atoms, such as a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.

[0014] In the present invention, the cycloalkenyl group is a monovalent group obtained by removing any one hydrogen atom from a cycloalkene. The cycloalkenyl group is preferably a cycloalkenyl group having 5 to 24 carbon atoms, and examples of the cycloalkenyl group include a cyclopentenyl group and a cyclohexenyl group.

[0015] In the present invention, a cycloalkynyl group is a monovalent group obtained by removing any one hydrogen atom from a cycloalkyne. The cycloalkynyl group is preferably a cycloalkynyl group having 8 to 24 carbon atoms, and examples thereof include a cyclooctynyl group.

[0016] In the present invention, the aromatic hydrocarbon group is a monovalent group obtained by removing any one hydrogen atom from an aromatic hydrocarbon. The number of carbon atoms in the aromatic hydrocarbon group is preferably 6 to 24, more preferably 6 to 20, and even more preferably 6 to 14. Examples of the aromatic hydrocarbon group include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-anthracenyl group, a 2-anthracenyl group, a 9-anthracenyl group, a 1-phenanthryl group, a 2-phenanthryl group, a 3-phenanthryl group, a 4-phenanthryl group, and a 9-phenanthryl group. Of these, a phenyl group is preferred. Effect of the Invention

[0017] The polyester resin of the present invention can achieve both a high Tg and low water absorbency at an excellent level. Furthermore, the molded article of the present invention contains the polyester resin and has low water absorbency and excellent heat resistance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] <Polyester resin> The polyester resin of the present invention is a polyester resin containing a structural unit (structural unit (A)) represented by the general formula (A) described below, and at least one of a structural unit (structural unit (B)) represented by the general formula (B) described below and a structural unit (structural unit (C)) represented by the general formula (C) described below. The polyester resin of the present invention having such a structure can achieve a high Tg and low water absorption at a desired high level. The reason for this is unclear, but is presumed to be as follows. In the polyester resin of the present invention, the structural unit (A) having a linear aliphatic hydrocarbon group having 6 or more carbon atoms contributes to the development of excellent low water absorption, but causes a decrease in Tg. The polyester resin of the present invention further comprises, in addition to the structural unit (A), a structural unit (B) having a branched alkyl group having 3 or more carbon atoms and a branched structure (substituent R 5 ), it is possible to increase Tg while suppressing the decrease in low water absorbency caused by the structural unit (A). In particular, the water absorbency can be lowered by an actual measurement value compared to the water absorbency (calculated value) calculated as the sum of the water absorbency of each of the structural units (A), (B), and (C) multiplied by the content ratio of each structural unit, and the measured value can be lowered, so that it is possible to achieve a sufficiently low water absorbency while maintaining a high Tg as a polyester resin. The polyester resin of the present invention can be suitably used, for example, as a low dielectric material due to its low water absorption.

[0019] The polyester resin of the present invention may be composed of a polyester containing the structural unit (A) and at least one of the structural unit (B) and the structural unit (C) (hereinafter referred to as the "polyester of the present invention"), or may be in the form of a composition in which the polyester of the present invention is blended with the additives described below. The polyester of the present invention will be described in detail below.

[0020] 〔polyester〕

[0021] (Structural unit (A)) [ka]

[0022] In the above formula, R 1 represents a linear aliphatic hydrocarbon group having 6 or more carbon atoms, and R 2 represents a hydrogen atom, an aliphatic hydrocarbon group, or an aromatic hydrocarbon group. 1 and R 2 are not bonded to form a ring. X represents a hydrocarbon group having a cyclic structure. * indicates a bond.

[0023] R 1 The linear aliphatic hydrocarbon group having 6 or more carbon atoms as the linear aliphatic hydrocarbon group is not particularly limited, and the above description of the linear aliphatic hydrocarbon group can be applied, so long as it has 6 or more carbon atoms. R 1 The linear aliphatic hydrocarbon group as the alkyl group has 6 or more carbon atoms, preferably 6 to 24 carbon atoms, more preferably 6 to 22 carbon atoms, further preferably 6 to 18 carbon atoms, particularly preferably 6 to 16 carbon atoms, and of these, 6 to 14 carbon atoms is preferred. R 1 is preferably a linear alkyl group, linear alkenyl group or linear alkynyl group having 6 or more carbon atoms, more preferably a linear alkyl group or linear alkenyl group having 6 or more carbon atoms, and even more preferably a linear alkyl group having 6 or more carbon atoms.

[0024] R 2The aliphatic hydrocarbon group and aromatic hydrocarbon group that can be used as the alkyl group are not particularly limited, and the above descriptions of the aliphatic hydrocarbon group and aromatic hydrocarbon group can be applied. R 2 The aliphatic hydrocarbon group which can be taken as the alkyl group is preferably an alkyl group, an alkenyl group or an alkynyl group, more preferably an alkyl group or an alkenyl group, and further preferably an alkyl group. R 2 It is preferred that the group does not contain a ring structure. R 2 is preferably a hydrogen atom, an alkyl group, an alkenyl group or an alkynyl group, more preferably a hydrogen atom or an alkyl group, still more preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and particularly preferably a hydrogen atom, a methyl group or an ethyl group.

[0025] The hydrocarbon group having a cyclic structure represented by X includes, for example, an arylene group, preferably phenylene, naphthalenediyl or anthracenediyl, more preferably phenylene.

[0026] (Structural unit (B)) [ka]

[0027] In the above formula, R 3 represents a branched alkyl group having 3 or more carbon atoms, and R 4 represents a hydrogen atom or an aliphatic hydrocarbon group having 1 to 5 carbon atoms. 3 and R 4 are not bonded to form a ring. X represents a hydrocarbon group having a cyclic structure. * indicates a bond.

[0028] R 3 The branched alkyl group having 3 or more carbon atoms as the above-mentioned branched alkyl group can be applied without any particular limitation as long as it has 3 or more carbon atoms. R 3The branched alkyl group as the alkyl group has 3 or more carbon atoms, preferably 3 to 11 carbon atoms, more preferably 3 to 7 carbon atoms, and further preferably 3 to 5 carbon atoms. R 3 In the branched alkyl group as R 4 The number of carbon atoms constituting the chain from the carbon atom having a bond to the carbon atom to which R is bonded to the carbon atom at the most terminal side (hereinafter referred to as "R 3 The number of carbon atoms constituting the longest chain of the bisphenol component (B-2) is preferably 7 or less, more preferably 5 or less, and even more preferably 3 or less. For example, in the structural unit derived from the bisphenol component (B-2) used in the examples, R 3 The longest chain of carbon atoms is three. Also, R 3 In the branched alkyl group as R 4 The number of carbon atoms constituting the chain from the carbon atom having a bond to the carbon atom to which R is bonded to the carbon atom having the first branched structure (hereinafter referred to as "R 3 The number of carbon atoms up to the branched structure of R is preferably 1 to 5, more preferably 1 to 3, and even more preferably 2 to 3. For example, in the structural unit derived from the bisphenol component (B-2) used in the examples, R 3 The number of carbon atoms up to the branched structure is two. R 3 is preferably a branched alkyl group, branched alkenyl group or branched alkynyl group having 3 or more carbon atoms, more preferably a branched alkyl group or branched alkenyl group having 3 or more carbon atoms, and even more preferably a branched alkyl group having 3 or more carbon atoms.

[0029] R 4 The aliphatic hydrocarbon group having 1 to 5 carbon atoms which can be taken as is not particularly limited as long as it has 1 to 5 carbon atoms, and the above descriptions of the aliphatic hydrocarbon group can be applied. R 4 The aliphatic hydrocarbon group which can be taken has 1 to 5 carbon atoms, and preferably 1 to 3 carbon atoms. R 4The aliphatic hydrocarbon group having 1 to 5 carbon atoms which can be taken as the alkyl group is preferably an alkyl group, an alkenyl group, or an alkynyl group having 1 to 5 carbon atoms, more preferably an alkyl group or an alkenyl group having 1 to 5 carbon atoms, and even more preferably an alkyl group having 1 to 5 carbon atoms. R 4 is preferably a hydrogen atom, or an alkyl group, alkenyl group or alkynyl group having 1 to 5 carbon atoms, more preferably a hydrogen atom, or an alkyl group or alkenyl group having 1 to 5 carbon atoms, and even more preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

[0030] X has the same meaning as X in the structural unit (A) described above.

[0031] (Structural unit (C)) [ka]

[0032] In the above formula, R 5 represents an aliphatic hydrocarbon group, and X represents a hydrocarbon group having a cyclic structure. n is an integer of 0 to 8, and m is an integer of 1 to 4. * indicates a bond.

[0033] R 5 The aliphatic hydrocarbon group as is not particularly limited, and the above description of the aliphatic hydrocarbon group can be applied. R 5 The aliphatic hydrocarbon group which can be taken as is preferably an alkyl group or an alkenyl group, more preferably an alkyl group having 1 to 6 carbon atoms, still more preferably an alkyl group having 1 to 3 carbon atoms. Multiple R 5 If there are multiple R 5 may be the same as each other or different from each other. In addition, multiple R 5 If there are multiple R 5 may be bonded to each other to form a ring, but preferably do not form a ring.

[0034] n is an integer of 0 to 8, preferably an integer of 0 to 4, more preferably 0 or 1, and even more preferably 0. m is an integer of 1 to 4, and an integer of 1 to 3 is preferable.

[0035] The 1,4-phenylene groups shown in the above general formulae (A) to (C) may all have the above-mentioned aliphatic hydrocarbon groups and / or aromatic hydrocarbon groups as substituents. In the present invention, structures in which the 1,4-phenylene groups shown in the above general formulae (A) to (C) have aliphatic hydrocarbon groups and / or aromatic hydrocarbon groups as substituents are also included in the structural units represented by the above general formulae (A) to (C). The substituent that the 1,4-phenylene group in the above general formulas (A) to (C) may have is preferably an aliphatic hydrocarbon group. In particular, it is preferable that the 1,4-phenylene group in the above general formulas (A) to (C) does not have a substituent, that is, is an unsubstituted group.

[0036] Specific examples of the structural unit (A) include a structural unit consisting of a structure selected from the (A) structures shown below and a structure selected from the (X) structures shown below. Specific examples of the structural unit (B) include a structural unit consisting of a structure selected from the (B) structures shown below and a structure selected from the (X) structures shown below. Specific examples of the structural unit (C) include a structural unit consisting of a structure selected from the (C) structures shown below and a structure selected from the (X) structures shown below. In the structures below, * indicates a bond. Further, specific examples of the bisphenol compounds (a) to (c) described later and structural units formed from dicarboxylic acid compounds or compounds with activated carboxy groups can also be referred to.

[0037] [ka]

[0038] In the polyester resin of the present invention, it is preferable that the polyester of the present invention contains at least both the structural unit represented by the above general formula (A) and the structural unit represented by the above general formula (B), from the viewpoint of realizing a high Tg while further enhancing low water absorbency.

[0039] The proportion of the structural unit (A) in the total of 100 mol % of the structural units (A), (B) and (C) is preferably from 15 to 60 mol %, and more preferably from 20 to 40 mol %. The proportion of the structural unit (B) in the total of 100 mol % of the structural units (A), (B) and (C) is preferably from 25 to 85 mol %, and more preferably from 50 to 80 mol %. The proportion of the structural unit (C) in the total of 100 mol % of the structural units (A), (B) and (C) is preferably from 15 to 60 mol %, and more preferably from 30 to 60 mol %. The structural unit (A) contained in the polyester of the present invention and the structural units (B) and (C) which may be contained therein may each be one type or two or more types. When two or more kinds of structural units (A) are present in the polyester of the present invention, the ratio of the structural units (A) means the total amount thereof. This also applies to the cases where two or more kinds of structural units (B) are present and the cases where two or more kinds of structural units (C) are present.

[0040] (Other structural units) The polyester of the present invention may contain structural units other than the above structural units (A), (B) and (C) (hereinafter referred to as "other structural units"). The other structural unit is not particularly limited as long as the effects of the present invention are exhibited, and examples thereof include ester structural units different from any of the above structural units (A), (B) and (C). Specific examples include structural units in which at least one of the structure derived from a diol compound and X in any of the above structural units (A), (B) and (C) is replaced with a different structure. The proportion of the structural units (A), (B) and / or (C) in the total structural units constituting the polyester of the present invention (total amount of the structural units (A) to (C)) may be, for example, 90 mol% or more in total, preferably 93 mol% or more, more preferably 95 mol% or more, and even more preferably 97 mol% or more. It is also preferable that all structural units contained in the polyester of the present invention are composed of the structural units (A), (B) and / or (C).

[0041] The structural units constituting the polyester of the present invention may be bonded randomly or in a block form, and the polyester of the present invention is preferably a random copolymer.

[0042] From the viewpoint of heat resistance of a molded article containing the polyester resin of the present invention, the Tg of the polyester of the present invention can be 120° C. or more, preferably 125° C. or more, and more preferably 130° C. or more. There is no particular upper limit, but a Tg of 200° C. or less is practical. In the present invention, the Tg of the polyester is a value measured by the method described in the examples below.

[0043] The water absorption rate of the polyester of the present invention can be less than 0.30% by mass, preferably less than 0.28% by mass, and more preferably less than 0.24% by mass. There is no particular lower limit. In the present invention, the water absorption rate of the polyester is a water absorption rate measured and calculated by the Karl Fischer evaporation method described in the examples below.

[0044] The polyester of the present invention has low water absorption and can be suitably used as a low dielectric material. The dielectric constant of the polyester of the present invention at 25° C. and 10 GHz can be less than 2.9, preferably less than 2.8, and more preferably less than 2.7. There is no particular lower limit, but a value of 2.0 or more is practical. The polyester of the present invention may have a dielectric loss tangent at 25° C. and 10 GHz of less than 0.045, preferably less than 0.040, and more preferably less than 0.035. There is no particular lower limit, but a value of 0.010 or more is practical. In the present invention, the dielectric constant and dielectric loss tangent of the polyester at 25° C. and 10 GHz are values ​​measured by the resonance perturbation method described in the examples below.

[0045] The MVR (melt volume-flow rate) of the polyester of the present invention is usually 5 ml / 10 min or more, preferably 20 ml / 10 min or more, from the viewpoint that excellent fluidity makes it easy to obtain a molded product with a thin thickness and good moldability can be obtained. There is no particular upper limit, but a value less than 60 ml / 10 min is practical. In the present invention, the MVR of a polyester is a value measured by the method described in the Examples below.

[0046] The weight average molecular weight (Mw) of the polyester of the present invention may be appropriately adjusted according to the chemical structures and the content ratios of the above-mentioned structural units (A) to (C) so as to exhibit an MVR capable of realizing good moldability, and may be, for example, from 10,000 to 200,000, preferably from 20,000 to 150,000, more preferably from 30,000 to 120,000, and even more preferably from 40,000 to 100,000. The weight average molecular weight can be adjusted by adjusting the equivalent ratio of the dicarboxylic acid compound or the compound with an activated carboxyl group to be reacted with the bisphenol compound. In the present invention, the weight average molecular weight of the polyester is a value measured by the method described in the examples below.

[0047] (Synthesis method) The polyester of the present invention can be produced by a conventional method without any particular limitation. For example, a polycondensation reaction between a diol compound and a dicarboxylic acid compound, or an ester exchange reaction (ester exchange method) between a diol compound and a compound having two ester structures in the molecule can be adopted. The dicarboxylic acid compound may be a compound in which the carboxy group in a dicarboxylic acid compound such as a dicarboxylic acid halide compound is activated.

[0048] (Diol Compound) In both the polycondensation reaction and the transesterification method, at least a bisphenol compound (a) represented by the following formula (a), a bisphenol compound (b) represented by the following formula (b), and a bisphenol compound (c) represented by the following formula (c) are used as diol compounds necessary for synthesizing the above-mentioned structural units (A) to (C).

[0049] [ka]

[0050] R in the above formulas (a) to (c) 1 ~R 5 , m and n are R in the above formulas (A) to (C). 1 ~R 5 , m and n, respectively, and have the same meaning.

[0051] Preferred specific examples of the bisphenol compounds (a) to (c) are described below, but the present invention is not limited to the forms in which these compounds are used.

[0052] (Bisphenol compound (a)) R 1 is a nonyl group, and R 2Examples of the bisphenol compound (a) in which is a hydrogen atom include 1,1-bis(4-hydroxyphenyl)decane, 1,1-bis(3-methyl-4-hydroxyphenyl)decane, 1,1-bis(2,3-dimethyl-4-hydroxyphenyl)decane, 1,1-bis(3,5-dimethyl-4-hydroxyphenyl)decane, 1,1-bis(3-ethyl-4-hydroxyphenyl)decane, 1,1-bis(3-propyl-4-hydroxyphenyl)decane, 1,1-bis(3-butyl-4-hydroxyphenyl)decane, and 1,1-bis(3-nonyl-4-hydroxyphenyl)decane. In addition, R in the above compound 1 and / or R 2 R in the above general formula (A) 1 and / or R 2 Specific examples include compounds in which

[0053] (Bisphenol compounds (b)) R 3 is a tert-butyl group, and R 4 Examples of the bisphenol compound (b) in which is a methyl group include 2,2-bis(4-hydroxyphenyl)-4-methylpentane, 2,2-bis(3-methyl-4-hydroxyphenyl)-4-methylpentane, 2,2-bis(2,3-dimethyl-4-hydroxyphenyl)-4-methylpentane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)-4-methylpentane, 2,2-bis(3-ethyl-4-hydroxyphenyl)-4-methylpentane, 2,2-bis(3-propyl-4-hydroxyphenyl)-4-methylpentane, 2,2-bis(3-butyl-4-hydroxyphenyl)-4-methylpentane, and 2,2-bis(3-nonyl-4-hydroxyphenyl)-4-methylpentane. In addition, R in the above compound 3 and / or R 4 R in the above general formula (B) 3 and / or R 4 Specific examples include compounds in which

[0054] (Bisphenol compounds (c)) n is 1, m is 3, and R 5 Examples of the bisphenol compound (c) in which is a methyl group include 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(3-methyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, and 1,1-bis(3-phenyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane. In addition, n, m and R in the above compound 5 At least one of n, m and R in the above general formula (C) is 5 Specific examples include compounds in which

[0055] (Dicarboxylic acid compounds, etc.) In the polycondensation reaction, at least a dicarboxylic acid compound represented by the following formula (x1) necessary for synthesizing X in the above-mentioned structural units (A) to (C) is used as the dicarboxylic acid compound. HOOC-X-COOH formula (x1) X in the above formula (x1) corresponds to X in the above formulae (A) to (C) and has the same definition. Examples of the dicarboxylic acid compound represented by the formula (x1) include terephthalic acid, isophthalic acid, phthalic acid, 2,7-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and anthracenedicarboxylic acid. Furthermore, compounds in which the carboxy group in the dicarboxylic acid compound represented by formula (x1), such as a dicarboxylic acid halide compound (preferably a dicarboxylic acid chloride compound), can also be preferably used.

[0056] (A compound with two ester structures in the molecule) In the transesterification reaction, at least a compound represented by the following formula (x2) necessary for synthesizing X in the above-mentioned structural units (A) to (C) is used as a compound having two ester structures in the molecule. ROC(=O)-XC(=O)OR formula (x2) X in the above formula (x2) corresponds to and has the same meaning as X in the above formulae (A) to (C). R represents an alkyl group, and is preferably methyl or ethyl. Examples of the compound represented by formula (x2) include dimethyl terephthalate and dimethyl isophthalate.

[0057] When the polyester of the present invention contains a structural unit (other structural unit) other than the above-mentioned structural units (A), (B), and (C), it can be produced by using, in addition to the above-mentioned bisphenol compounds (a) to (c), a diol compound corresponding to the other structural unit, or by using, in addition to the dicarboxylic acid compound represented by the above formula (x1) or a compound with an activated carboxy group, or the compound represented by the above formula (x2), a dicarboxylic acid compound corresponding to the other structural unit or a compound having two ester structures in the molecule. Specific examples of the aromatic diols (bisphenol compounds) described in JP-A-2003-29447, paragraph

[0026] and the like, which are different from the above-mentioned bisphenol compounds (a), (b), and (c), include aliphatic dihydroxy compounds (diol compounds) described in JP-A-2003-29447, paragraph

[0027] and the like, as well as dicarboxylic acid compounds such as fumaric acid, malonic acid, succinic acid, glutaric acid, adipic acid, and maleic acid, and compounds with activated carboxy groups.

[0058] The polyester of the present invention can be produced by a conventional polymerization method, such as interfacial polymerization, melt polymerization, or solution polymerization.

[0059] [Additives] The polyester resin of the present invention may be in a form in which an additive is blended with the polyester of the present invention. As the additives, additives commonly used as additives to polyester resins can be used within the range that does not impair the effects of the present invention. For example, flame retardants, release agents, ultraviolet absorbers, dyes, pigments, fluorescent brightening agents, anti-dripping agents, antistatic agents, heat stabilizers, antioxidants, anti-fogging agents, lubricants, anti-blocking agents, dispersants, antibacterial agents, etc. can be used according to various applications.

[0060] (Application) The polyester resin of the present invention can be used in any application without particular limitation, and examples thereof include electronic device housings, metal wire coating films, and polarizing plate protective films for display devices. The polyester resin of the present invention is excellent in achieving both a high Tg and low water absorption, and therefore can be suitably used as a low dielectric material that requires a low dielectric constant and a low dielectric loss tangent.

[0061] <Molded products> The molded article of the present invention comprises the polyester resin of the present invention. The molding method using the polyester resin of the present invention is not particularly limited, and in addition to molding methods used for thermoplastic resins such as injection molding, extrusion molding, vacuum molding, and blow molding, the fused deposition modeling method, which is a typical method for manufacturing 3D printers, in which a resin is melted and laminated, can also be applied. The polyester resin of the present invention can achieve both high Tg and low water absorption even when it has an MVR (usually 5 ml / 10 min or more (preferably 20 ml / 10 min or more) less than 60 ml / 10 min) that provides good moldability, and is therefore suitable for use in molding thin-walled optical components. Specifically, the polyester resin of the present invention can be pelletized and molded into pellets by various molding methods to produce thin-walled optical components, and is particularly suitable for use in molding thin-walled optical components by injection molding. Regarding the definition and forming method of the thin-walled optical component, in the description of paragraphs

[0095] to

[0097] of WO 2017 / 099226, "polycarbonate resin composition" is read as "polyester resin of the present invention" and applied to this specification. EXAMPLES

[0062] The present invention will be described in more detail below with reference to the following examples. The materials, amounts, ratios, processing contents, processing procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the specific examples shown below.

[0063] <Polyester synthesis example> (1) Synthesis of polyester 5 In a 500 ml separable flask, 7.62 g of 4-[1-(4-hydroxyphenyl)-1,3-dimethyl-butyl]phenol, 3.94 g of 4,4'-(decane-1,1-diyl)diphenol, 0.045 g of t-butylphenol, 100 ml of dehydrated dichloromethane, and 10.76 g of diisopropylethylamine were added, and the flask was cooled to 5°C with ice water while flowing nitrogen. After the contents were dissolved and became uniform, a solution of 4.10 g of terephthalic acid dichloride and 4.10 g of isophthalic acid dichloride dissolved in 20 ml of dichloromethane was gradually added dropwise so that the internal temperature was kept at 5 to 15°C. After the dropwise addition, the mixture was stirred at 10 to 15°C for 30 minutes, and then stirred at room temperature (25°C) for 3 hours. The reaction liquid was added dropwise to methanol to obtain a powder, which was then filtered and dried to obtain polyester 5. The dry yield was 12.1 g (yield 86%), the weight average molecular weight was 58,000, and the MVR was 10 ml / 10 min.

[0064] (2) Synthesis of polyesters 1-4, 6-12, and c1-c3 Polyesters 1 to 4, 6 to 12, and c1 to c3 were obtained in the same manner as in the synthesis of polyester 5, except that the bisphenol component was changed to one shown in Table 1 below. Each polyester was prepared and synthesized so that the MVR of the polyester was in the range of 5 ml / 10 min or more and less than 30 ml / 10 min, which shows good moldability, and the weight average molecular weight was in the range of 30,000 to 100,000.

[0065] The MVR was measured for a dried sample of the synthesized polyester by a constant temperature method using a flow tester CFT-500D (trade name, manufactured by Shimadzu Corporation) under the following conditions. (Measurement conditions) Measurement temperature: 300℃ Preheat time: 300 seconds Test force: 6Kgf / cm 2 Die hole diameter: φ1mm

[0066] The weight average molecular weight (Mw) of the synthesized polyester refers to the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC). (Measurement condition 1) Measuring instrument: TOSOH EcoSEC HLC-8320GPC (product name, manufactured by Tosoh Corporation) Columns: TOSOH TSKgel Super HZM-H (product name, manufactured by Tosoh Corporation), TOSOH TSKgel Super HZ4000 (product name, manufactured by Tosoh Corporation), and TOSOH TSKgel Super HZ2000 (product name, manufactured by Tosoh Corporation) are connected together. Carrier: Tetrahydrofuran (containing BHT stabilizer) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Measurement temperature: 40℃ Carrier flow rate: 0.35ml / min Sample concentration: 0.05% by mass Detector: RI (refractive index) detector, UV detector (254 nm)

[0067] Polyesters 1 to 12 are polyesters of the present invention, and polyesters c1 to c3 are polyesters for comparison.

[0068] <Evaluation> The polyester obtained was subjected to the following measurements and evaluations, and the results are shown in Table 1 below.

[0069] [Evaluation 1: Water absorbency evaluation] A uniform membrane with a thickness of about 0.5 mm was prepared by heat pressing (about 240 to 280°C), and about 0.2 g was cut out from the prepared membrane and soaked in ion-exchanged water. After soaking at 25°C for one week to prepare a saturated water-containing sample, water droplets on the surface were wiped off and measurements were performed using the Karl Fischer vaporization method (measurement device: AQ-2250 (trade name, Kitahama Seisakusho Co., Ltd.), vaporization device: AQS-225320 (trade name, Hiranuma Sangyo Co., Ltd.), reagent used: Aqualite RS-A (general use, trade name, Hiranuma Sangyo Co., Ltd.), measurement temperature 180°C, nitrogen gas flow rate: 200 ml / min), and the water absorption rate was calculated from the following formula to evaluate the water absorption. Water absorption rate (mass%)=100%×(CD) / E C means the measured moisture content of the saturated water-containing sample, D means the measured moisture content of the blank, and E means the amount of the saturated water-containing sample taken for the measurement.

[0070] [Evaluation 2: Evaluation of glass transition temperature (Tg)] The glass transition temperature (Tg) used was that listed in the table in Chapter 36 of the POLYMER HANDBOOK 4th edition. If the glass transition temperature was not listed in the reference, the value was measured under the following measurement conditions. Tg was evaluated according to the following criteria. (Measurement of Tg) The glass transition temperature (Tg) was measured for a dried polyester sample using a differential scanning calorimeter: X-DSC7000 (trade name, manufactured by SII Nano Technology Co., Ltd.) under the following measurement conditions. The measurement was performed twice for the same sample, and the second measurement result was used. (Measurement conditions) Atmosphere in the measurement room: Nitrogen gas (50ml / min) Heating rate: 5℃ / min Measurement start temperature: -80℃ End of measurement temperature: 250℃ Sample pan: Aluminum pan Mass of measurement sample: 5mg Calculation of Tg: Tg was calculated by rounding off the decimal point of the midpoint between the start point and the end point of the decline in a DSC (differential scanning calorimetry) chart.

[0071] [Evaluation 3: Dielectric constant and dielectric tangent evaluation] The dielectric loss tangent was measured by the resonance perturbation method at a frequency of 10 GHz. A 10 GHz cavity resonator (Kanto Electronics Application Development Co., Ltd., product name: CP531) was connected to a network analyzer (Agilent Technology, product name: E8363B), and a film-like test piece cut out from the uniform film prepared in the above evaluation 1 was inserted into the cavity resonator and allowed to stand for 96 hours under an environment of 25°C and 60% RH. The dielectric constant and dielectric loss tangent of the film were measured from the change in resonance frequency before and after the test piece was inserted and left to stand for 96 hours, and were evaluated according to the following criteria. - Evaluation criteria (dielectric constant) - 5: 2.0 or greater but less than 2.7 4: 2.7 or more, but less than 2.8 3: 2.8 or more, but less than 2.9 2: 2.9 or more, but less than 3.0 1: 3.0 or higher - Evaluation criteria (dielectric tangent) - 5: 0.010 or more and less than 0.035 4: 0.035 or more and less than 0.040 3: 0.040 or more and less than 0.045 2: 0.045 or more and less than 0.050 1: 0.050 or higher

[0072] [Table 1]

[0073] (Table Notes) Nos. 1 to 12 and c1 to c3 respectively mean polyesters 1 to 12 of the present invention and polyesters c1 to c3 for comparison. The individual monomer components are as follows:

[0074] [ka]

[0075] Polyesters 1 to 12 and c1 to c3 are polyesters containing a structural unit derived from a bisphenol component and a structural unit derived from a dicarboxylic acid component in a 1:1 molar ratio. The column for the monomer component of the bisphenol component compounds (a) to (c) lists the bisphenol components that constitute the structural units derived from the bisphenol components in the structural units represented by the general formulas (A) to (C) (structural units obtained by excluding the structural unit represented by -C(=O)-XC(=O)- from the structural units represented by each general formula). In the column of the monomer component of the X component of the dicarboxylic acid component (dicarboxylic acid chloride component), the dicarboxylic acid component constituting the structural unit (-C(=O)-XC(=O)-) derived from the dicarboxylic acid component in the structural units represented by the general formulas (A) to (C) is described. The molar ratio of the bisphenol component compounds (a) to (c) means the ratio of the structural units derived from each bisphenol component to the total 100 mol % of the structural units derived from the bisphenol components constituting the polyester. That is, it corresponds to the ratio of the structural units represented by each of the general formulas (A) to (C) to the total 100 mol % of the structural units represented by the general formulas (A) to (C) constituting the polyester. The unit is mol %. The molar ratio of the dicarboxylic acid components X-1 and X-2 means the ratio of the structural units derived from each dicarboxylic acid component to the total of 100 mol % of the structural units derived from the dicarboxylic acid components constituting the polyester, expressed in mol %. "-" indicates that the corresponding structural unit is not contained. Tg indicates the glass transition temperature, and its unit is °C. The unit of water absorption is mass %.

[0076] From Table 1, we can see the following: Comparative polyester c1 consisting of structural units represented by general formula (A) had a low glass transition temperature of 70° C. Comparative polyester c2 consisting of structural units represented by general formula (B) had a high water absorption rate of 0.35% by mass, and comparative polyester c3 consisting of structural units represented by general formula (C) had a high water absorption rate of 0.55% by mass. In contrast, polyesters 1 to 12 of the present invention, which contain a structural unit represented by general formula (A) and at least one of a structural unit represented by general formula (B) and a structural unit represented by general formula (C), achieved both a high Tg of 120° C. or higher and a low water absorption rate of less than 0.30% by mass. In particular, the water absorption rates (measured values) shown by polyesters 5, 8 to 12 of the present invention were significantly lower than the water absorption rates (calculated values) calculated as the sum of the water absorption rates of polyesters c1 to c3 for comparison multiplied by the content ratios (molar ratios×0.01) of the structural units in polyesters 5, 8 to 12, respectively, and showed low water absorption rates lower than the water absorption rates simply predicted from the structural units, and it was found that sufficient low water absorption could be achieved while maintaining a high Tg as a polyester. For example, in polyester 11 of the present invention, the molar ratio of the structural unit derived from bisphenol component (A-2), which is a structural unit represented by general formula (A), to the structural unit derived from bisphenol component (B-2), which is a structural unit represented by general formula (B), is 50:50. The water absorption rate (calculated value) of polyester 11 of the present invention obtained using this content ratio is 0.16% by mass×50×0.01+0.35% by mass×50×0.01=0.26% by mass, whereas the measured value is 0.17% by mass, indicating that a lower water absorption rate can be achieved.

Claims

1. A polyester resin comprising a structural unit represented by the following general formula (A) and at least one of a structural unit represented by the following general formula (B) and a structural unit represented by the following general formula (C). 【Chemistry 1】 In the above formula, R １ represents a linear aliphatic hydrocarbon group having 6 or more carbon atoms; R ２ represents a hydrogen atom, an aliphatic hydrocarbon group, or an aromatic hydrocarbon group. １ and R ２ are not bonded to form a ring. X represents a hydrocarbon group having a cyclic structure. * indicates a bond. 【Chemistry 2】 In the above formula, R ３ represents a branched alkyl group having 3 or more carbon atoms; R ４ represents a hydrogen atom or an aliphatic hydrocarbon group having 1 to 5 carbon atoms. ３ and R ４ are not bonded to form a ring. X represents a hydrocarbon group having a cyclic structure. * indicates a bond. 【Chemistry 3】 In the above formula, R ５ represents an aliphatic hydrocarbon group, and X represents a hydrocarbon group having a cyclic structure. n is an integer from 0 to 8, and m is an integer from 1 to 4. * indicates a bond. The 1,4-phenylene group in the above general formulas (A) to (C) may have an aliphatic hydrocarbon group and / or an aromatic hydrocarbon group as a substituent.

2. 2. The polyester resin of claim 1, wherein X is an arylene group.

3. The polyester resin according to claim 1, comprising at least a structural unit represented by the general formula (A) and a structural unit represented by the general formula (B).

4. A molded article comprising the polyester resin according to any one of claims 1 to 3.

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