Polyester and feeding bottle

Abstract

The present invention provides a polyester wherein: a dicarboxylic acid constituent unit includes 72.5 mol% or more of a constituent unit derived from 2,6-naphthalenedicarboxylic acid and / or an ester derivative thereof among a total 100 mol% of said dicarboxylic acid constituent units; and a diol constituent unit includes 27.5 mol% or more of a constituent unit derived from 1,4-cyclohexanedimethanol and a constituent unit derived from 2,2,4,4-tetramethyl-1,3-cyclobutanediol among a total 100 mol% of said diol constituent units. A feeding bottle according to the present invention is formed using said polyester.

Description

Polyester and baby bottles

[0001] The present invention relates to polyesters and baby bottles.

[0002] Polyesters are widely used in fields such as packaging materials, molded products, and films due to their excellent heat resistance, transparency, and mechanical properties. Polyethylene terephthalate (PET) is a resin with a good balance of mechanical properties, solvent resistance, aroma retention, weather resistance, and recyclability, and is widely used primarily for bottles and films. However, PET has drawbacks in terms of heat resistance. Since the glass transition temperature of PET is approximately 80°C, it is unsuitable for applications requiring high heat resistance, such as products used inside automobiles, packaging materials for import and export, food packaging materials that are retorted or heated in a microwave oven, and baby bottles and tableware that are heat sterilized.

[0003] JP 2017-105873 A

[0004] To address the above-mentioned issues, for example, Patent Document 1 proposes a polyester resin having dicarboxylic acid structural units and diol structural units, in which 5 to 90 mol % of the diol structural units are diol units having a cyclic acetal skeleton and 5 to 90 mol % are alicyclic diol units. However, for applications requiring heat resistance and impact resistance, such as baby bottles, further improvements in these properties are required.

[0005] Therefore, an object of the present invention is to provide a polyester and a baby bottle having high heat resistance and impact resistance.

[0006] [1] A baby bottle formed using a polyester containing dicarboxylic acid structural units and diol structural units, wherein the dicarboxylic acid structural units contain 72.5 mol% or more of structural units derived from 2,6-naphthalenedicarboxylic acid and / or an ester derivative thereof, based on a total of 100 mol% of the dicarboxylic acid structural units, and the diol structural units contain 27.5 mol% or more of structural units derived from 1,4-cyclohexanedimethanol and structural units derived from 2,2,4,4-tetramethyl-1,3-cyclobutanediol, based on a total of 100 mol% of the diol structural units. [2] The baby bottle according to [1], wherein the dicarboxylic acid structural units contain 75 mol% or more of structural units derived from 2,6-naphthalenedicarboxylic acid and / or an ester derivative thereof, based on a total of 100 mol% of the dicarboxylic acid structural units. [3] The baby bottle according to [1] or [2], wherein the diol structural units contain 5 mol% or more of structural units derived from 2,2,4,4-tetramethyl-1,3-cyclobutanediol, based on a total of 100 mol% of the diol structural units. [4] The baby bottle according to any one of [1] to [3], wherein the dicarboxylic acid structural units further contain structural units derived from terephthalic acid and / or an ester derivative thereof. [5] The baby bottle according to any one of [1] to [4], wherein the diol structural units further contain structural units derived from ethylene glycol. [6] A polyester comprising dicarboxylic acid structural units and diol structural units, wherein the dicarboxylic acid structural units comprise 72.5 mol% or more of structural units derived from 2,6-naphthalenedicarboxylic acid and / or an ester derivative thereof, based on a total of 100 mol% of the dicarboxylic acid structural units; and the diol structural units comprise 27.5 mol% or more of structural units derived from 1,4-cyclohexanedimethanol and structural units derived from 2,2,4,4-tetramethyl-1,3-cyclobutanediol, based on a total of 100 mol% of the diol structural units.

[0007] According to the present invention, a polyester and a baby bottle having high heat resistance and impact resistance can be provided.

[0008] Hereinafter, an embodiment of the present invention will be described in detail, but the present invention is not limited to this embodiment. In this specification, "A to B" (A and B are numerical values) means "greater than or equal to A and less than or equal to B."

[0009] [First Embodiment] The baby bottle according to the first embodiment is a baby bottle formed using a polyester. In the first embodiment, the polyester contains dicarboxylic acid structural units and diol structural units, and the dicarboxylic acid structural units contain 72.5 mol% or more of structural units derived from 2,6-naphthalenedicarboxylic acid and / or its ester derivatives, based on a total of 100 mol% of the dicarboxylic acid structural units. Furthermore, in the first embodiment, the diol structural units in the polyester contain 27.5 mol% or more of structural units derived from 1,4-cyclohexanedimethanol and structural units derived from 2,2,4,4-tetramethyl-1,3-cyclobutanediol, based on a total of 100 mol% of the diol structural units. In the first embodiment, by forming a baby bottle using a polyester containing such structural units, a baby bottle with high heat resistance and impact resistance can be provided.

[0010] Here, baby bottles are used for infants after being heat sterilized by boiling or steaming, and may also be carried by users when they go out. Therefore, baby bottles are required to have heat resistance that can withstand high temperatures and high impact resistance that can prevent breakage when accidentally dropped while holding contents, ensuring safety, even if the bottle is lightweight (e.g., thin-walled). Polyesters containing the above-described desired structural units have the high heat resistance and impact resistance required for baby bottles, making them particularly suitable for use in baby bottles. Furthermore, baby bottles are required to have high transparency so that the state of the milk being given to infants and the state of the container (e.g., the presence or absence of residual solid milk, dirt in the milk or on the container, etc.) can be confirmed. Polyesters containing the above-described desired structural units also have the high transparency required for baby bottles, making them particularly suitable for use in baby bottles.

[0011] The polyester in the first embodiment will be described below. In the first embodiment, the polyester contains the following dicarboxylic acid structural units and diol structural units.

[0012] (Dicarboxylic Acid Structural Units) In the first embodiment, the dicarboxylic acid structural units contain 72.5 mol % or more of structural units derived from 2,6-naphthalenedicarboxylic acid and / or an ester derivative thereof, based on a total of 100 mol % of the dicarboxylic acid structural units. By containing 72.5 mol % or more of structural units derived from 2,6-naphthalenedicarboxylic acid and / or an ester derivative thereof in the dicarboxylic acid structural units, the heat resistance of the polyester can be improved. Note that, hereinafter, structural units derived from 2,6-naphthalenedicarboxylic acid and / or an ester derivative thereof will also be referred to as "2,6-naphthalenedicarboxylic acid structural units." This also applies to structural units derived from specific dicarboxylic acids and / or ester derivatives thereof.

[0013] The content of 2,6-naphthalenedicarboxylic acid structural units in the dicarboxylic acid structural units is preferably 75 mol% or more, more preferably 90 mol% or more. The upper limit of the content of 2,6-naphthalenedicarboxylic acid structural units in the dicarboxylic acid structural units is not particularly limited, but can be, for example, 100 mol% or less, or can be 95 mol% or less, 90 mol% or less, 85 mol% or less, or 80 mol% or less.

[0014] The dicarboxylic acid constituent unit may contain any dicarboxylic acid constituent unit other than the 2,6-naphthalenedicarboxylic acid constituent unit. Examples of such dicarboxylic acid constituent units include aliphatic dicarboxylic acid units such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, cyclohexanedicarboxylic acid, decalindicarboxylic acid, norbornanedicarboxylic acid, tricyclodecanedicarboxylic acid, pentacyclododecanedicarboxylic acid, 3,9-bis(1,1-dimethyl-2-carboxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, and 5-carboxy-5-ethyl-2-(1,1-dimethyl-2-carboxyethyl)-1,3-dioxane; and units derived from aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, 2-methylterephthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, and tetralindicarboxylic acid, and / or ester derivatives thereof. The dicarboxylic acid constituent unit may contain one or more types of these dicarboxylic acid constituent units other than the 2,6-naphthalenedicarboxylic acid constituent unit.

[0015] In the first embodiment, when the dicarboxylic acid structural units contain dicarboxylic acid structural units other than 2,6-naphthalenedicarboxylic acid structural units, the dicarboxylic acid structural units preferably contain structural units derived from terephthalic acid and / or an ester derivative thereof. By including terephthalic acid structural units other than 2,6-naphthalenedicarboxylic acid structural units as dicarboxylic acid structural units, it is possible to obtain a more inexpensive polyester while maintaining impact resistance. When terephthalic acid structural units are included, the content of terephthalic acid structural units in the dicarboxylic acid structural units is preferably more than 0 mol% and less than 27.5 mol%, and more preferably more than 0 mol% and less than 25 mol%, relative to a total of 100 mol% of the dicarboxylic acid structural units.

[0016] In the first embodiment, the ester derivative from which the dicarboxylic acid structural unit can be derived is not particularly limited, but examples thereof include diesters of dicarboxylic acids and saturated hydrocarbon alcohols such as methanol.

[0017] (Diol Structural Units) In the first embodiment, the diol structural units contain 27.5 mol% or more of structural units derived from 1,4-cyclohexanedimethanol and structural units derived from 2,2,4,4-tetramethyl-1,3-cyclobutanediol, based on a total of 100 mol% of the diol structural units. When the diol structural units contain 27.5 mol% or more of structural units derived from 1,4-cyclohexanedimethanol, the impact resistance of the polyester can be improved. Furthermore, when the diol structural units contain structural units derived from 2,2,4,4-tetramethyl-1,3-cyclobutanediol, the heat resistance of the polyester can be improved. Note that, hereinafter, structural units derived from 1,4-cyclohexanedimethanol or 2,2,4,4-tetramethyl-1,3-cyclobutanediol are also referred to as "1,4-cyclohexanedimethanol structural units" and "2,2,4,4-tetramethyl-1,3-cyclobutanediol structural units." These terms also apply to structural units derived from specific diols.

[0018] The content of 1,4-cyclohexanedimethanol structural units in the diol structural units may be 30 mol% or more, or may be 40 mol% or more, or 50 mol% or more. Furthermore, the upper limit of the content of 1,4-cyclohexanedimethanol structural units in the diol structural units is not particularly limited, but can be, for example, 100 mol% or less, or can be 90 mol% or less, 80 mol% or less, 70 mol% or less, 60 mol% or less, 50 mol% or less, 40 mol% or less, or 35 mol% or less.

[0019] The content of 2,2,4,4-tetramethyl-1,3-cyclobutanediol structural units in the diol structural units is preferably 5 mol% or more, more preferably 7.5 mol% or more, and even more preferably 10 mol% or more. The upper limit of the content of 2,2,4,4-tetramethyl-1,3-cyclobutanediol structural units in the diol structural units is preferably 80 mol% or less, more preferably 70 mol% or less, even more preferably 60 mol% or less, and particularly preferably 55 mol% or less. The content of 2,2,4,4-tetramethyl-1,3-cyclobutanediol structural units in the diol structural units is 5 to 80 mol%, 5 to 70 mol%, 5 to 60 mol%, 5 to 55 mol%, 5 to 45 mol%, 5 to 35 mol%, 5 to 25 mol%, 5 to 15 mol%, 15 to 80 mol%, 15 to 70 mol%, 15 to 60 mol%, 15 to 55 mol%, 15 to 45 mol%, 15 The diol structural units may be 2,2,4,4-tetramethyl-1,3-cyclobutanediol structural units in an amount of 5 mol% or more, or ...

[0020] In the first embodiment, the diol structural unit may include any diol structural unit other than a 1,4-cyclohexanedimethanol structural unit and a 2,2,4,4-tetramethyl-1,3-cyclobutanediol structural unit. Alicyclic diol structural units among such diol structural units are not particularly limited, but examples include structural units derived from 1,3-cyclohexanedimethanol, 1,2-decahydronaphthalenedimethanol, 1,3-decahydronaphthalenedimethanol, 1,4-decahydronaphthalenedimethanol, 1,5-decahydronaphthalenedimethanol, 1,6-decahydronaphthalenedimethanol, 2,7-decahydronaphthalenedimethanol, tetralindimethanol, norbornenedimethanol, tricyclodecanedimethanol, pentacyclododecanedimethanol, etc.

[0021] Furthermore, in the first embodiment, examples of the optional diol structural unit other than those described above include structural units derived from aliphatic diols such as ethylene glycol, trimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, propylene glycol, and neopentyl glycol; polyether compounds such as polyethylene glycol, polypropylene glycol, and polybutylene glycol; bisphenols such as 4,4'-(1-methylethylidene)bisphenol, methylenebisphenol (bisphenol F), 4,4'-cyclohexylidenebisphenol (bisphenol Z), and 4,4'-sulfonylbisphenol (bisphenol S); alkylene oxide adducts of the above bisphenols; aromatic dihydroxy compounds such as hydroquinone, resorcinol, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl ether, and 4,4'-dihydroxydiphenylbenzophenone; and alkylene oxide adducts of the above aromatic dihydroxy compounds.

[0022] In the first embodiment, when the diol structural units include any diol structural units other than the 1,4-cyclohexanedimethanol structural unit and the 2,2,4,4-tetramethyl-1,3-cyclobutanediol structural unit, it is preferable to include an ethylene glycol structural unit. By including an ethylene glycol structural unit, a more inexpensive polyester can be obtained. In this case, the content of the ethylene glycol structural unit is preferably 15 mol% or more, more preferably 20 mol% or more, based on a total of 100 mol% of the diol structural units. The upper limit of this content is preferably 67.5 mol% or less, more preferably 65 mol% or less, even more preferably 62.5 mol% or less, and even more preferably 60 mol% or less.

[0023] The content of ethylene glycol structural units in the diol structural units is 15 to 67.5 mol%, 15 to 65 mol%, 15 to 62.5 mol%, 15 to 60 mol%, 15 to 55 mol%, 15 to 45 mol%, 15 to 35 mol%, 15 to 25 mol%, 25 to 67.5 mol%, 25 to 65 mol%, 25 to 62.5 mol%, 25 It may be up to 60 mol%, 25 to 55 mol%, 25 to 45 mol%, 25 to 35 mol%, 35 to 67.5 mol%, 35 to 65 mol%, 35 to 62.5 mol%, 35 to 60 mol%, 35 to 55 mol%, 35 to 45 mol%, 45 to 67.5 mol%, 45 to 65 mol%, 45 to 55 mol%, or 55 to 65 mol%.

[0024] In the first embodiment, the combination of the dicarboxylic acid constituent units and the diol constituent units is not particularly limited, but for example, a preferred combination is one in which the dicarboxylic acid constituent units are composed of 72.5 mol % to 100 mol % of 2,6-naphthalenedicarboxylic acid constituent units and 0 to 25 mol % of terephthalic acid constituent units, relative to a total of 100 mol % of the dicarboxylic acid constituent units, and the diol constituent units are composed of 27.5 to 80 mol % of 1,4-cyclohexanedimethanol constituent units, 5 to 55 mol % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol constituent units, and 15 to 67.5 mol % of ethylene glycol constituent units, relative to a total of 100 mol % of the diol constituent units.

[0025] (Other Components) In the first embodiment, the polyester may contain, within the scope of the present invention, monoalcohol units such as butyl alcohol, hexyl alcohol, and octyl alcohol; trihydric or higher polyhydric alcohol units such as trimethylolpropane, glycerin, 1,3,5-pentanetriol, and pentaerythritol; monocarboxylic acid units such as benzoic acid, propionic acid, and butyric acid; polycarboxylic acid units such as trimellitic acid and pyromellitic acid; and oxyacid units such as glycolic acid, lactic acid, hydroxybutyric acid, 2-hydroxyisobutyric acid, and hydroxybenzoic acid.

[0026] The composition may also contain a polymerization catalyst and various additives. Examples of additives include antioxidants, light stabilizers, ultraviolet absorbers, plasticizers, extenders, matting agents, drying regulators, antistatic agents, antisettling agents, surfactants, flow improvers, drying oils, waxes, fillers, colorants, reinforcing agents, surface smoothing agents, leveling agents, curing reaction accelerators, and chain extenders. Furthermore, resins and oligomers such as polyolefins, polyesters, polyamides, polycarbonates, acrylonitrile resins, vinyl chloride resins, vinyl acetate resins, polyacrylic acid, polymethacrylic acid, polystyrenes, ABS resins, polyimide resins, and AS resins may also be added.

[0027] (Physical Properties of Polyester) In the first embodiment, the glass transition temperature of the polyester is preferably 123°C or higher, more preferably 125°C or higher, from the viewpoint of heat resistance. When the glass transition temperature is within the above range, the polyester can be suitably used in baby bottles, which require high heat resistance. The glass transition temperature can be measured based on the method described in the examples below. The glass transition temperature can be adjusted to fall within the above-mentioned preferred range, for example, by appropriately selecting the dicarboxylic acid constituent units and diol constituent units of the polyester based on the above-mentioned preferred embodiments.

[0028] In the first embodiment, the calorific value of the crystallization peak during cooling of the polyester is preferably 5 J / g or less, more preferably 3 J / g or less. When the crystallization peak during cooling is within the above range, the crystallinity of the polyester tends to be lower. Therefore, the polyester can have high transparency, and baby bottles using the polyester can also have high transparency. The calorific value of the crystallization exothermic peak during cooling can be measured using a differential scanning calorimeter by heating the polyester in a nitrogen gas (30 ml / min) stream at a heating rate of 20°C / min, holding it at 280°C for 1 minute, and then cooling it at a cooling rate of 10°C / min, based on the area of ​​the exothermic peak. Furthermore, the calorific value of the crystallization peak during cooling can be adjusted to the above-mentioned preferred range by, for example, appropriately selecting the dicarboxylic acid constituent units and diol constituent units of the polyester based on the above-mentioned preferred embodiment.

[0029] In the first embodiment, it is preferable that the number of breaks of test pieces obtained from the polyester in an Izod test under the following conditions is zero. The Izod test is performed in accordance with JIS K7110 using 10 unnotched test pieces, each 63.5 mm long, 12.7 mm wide, and 3.2 mm thick, obtained by injection molding the polyester, using a 4 J hammer. When the number of breaks is zero, the product is suitable for use in baby bottles, which require high impact resistance. The number of breaks can be adjusted to fall within the preferred range described above, for example, by appropriately selecting the dicarboxylic acid constituent units and diol constituent units of the polyester based on the preferred embodiments described above.

[0030] (Method of manufacturing a baby bottle) In the first embodiment, the method of manufacturing the polyester is not particularly limited, and conventionally known methods can be applied. Examples include melt polymerization methods such as transesterification and direct esterification, and solution polymerization. Conventionally known transesterification catalysts, esterification catalysts, etherification inhibitors, various stabilizers such as heat stabilizers and light stabilizers, and polymerization regulators can also be used. Furthermore, in the first embodiment, the method of manufacturing a baby bottle using the polyester is not particularly limited, and conventionally known methods can be applied. Examples include extrusion blow molding, extrusion stretch blow molding, thermoforming, injection blow molding, and injection stretch blow molding.

[0031] Second Embodiment Next, a polyester according to a second embodiment will be described. The polyester according to the second embodiment is a polyester containing dicarboxylic acid structural units and diol structural units, wherein the dicarboxylic acid structural units contain 72.5 mol % or more of structural units derived from 2,6-naphthalenedicarboxylic acid and / or an ester derivative thereof per 100 mol % of the dicarboxylic acid structural units, and the diol structural units contain 27.5 mol % or more of structural units derived from 1,4-cyclohexanedimethanol and structural units derived from 2,2,4,4-tetramethyl-1,3-cyclobutanediol per 100 mol % of the diol structural units. In the second embodiment, a polyester having high heat resistance and impact resistance can be provided.

[0032] The polyester of the second embodiment can be the same as the polyester used in the baby bottle of the first embodiment, and the preferred aspects of the polyester in the first embodiment described above can also be applied to the polyester of the second embodiment.

[0033] The polyester of the second embodiment can be used for baby bottles or for applications requiring heat resistance and impact resistance equivalent to those required for baby bottles, such as products used inside automobiles, packaging materials for import and export, food packaging materials that undergo retort treatment or microwave heating, and containers such as tableware that undergo heat sterilization treatment.

[0034] Although the embodiments of the present invention have been described above, the baby bottle and polyester of the present invention are not limited to the above examples and can be modified as appropriate.

[0035] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples in any way.

[0036] [Evaluation Methods] The polyesters in the examples were evaluated as follows: (1) Composition and Content of Dicarboxylic Acid Structural Units and Diol Structural Units in Polyester The composition and content of dicarboxylic acid structural units and diol structural units contained in the polyester were determined by the following methods: １ Analysis was performed by H-NMR measurement using an Ascend™ 500 measuring device manufactured by Bruker BioSpin K.K. Deuterated chloroform was used as the solvent.

[0037] (2) Heat Resistance Heat resistance was evaluated by measuring the glass transition temperature (Tgm) of the polyester. The glass transition temperature was measured using a differential scanning calorimeter (model: DSC / TA-50WS) manufactured by Shimadzu Corporation, by placing approximately 10 mg of a sample in an unsealed aluminum container and measuring it in a nitrogen gas (30 ml / min) stream at a heating rate of 20°C / min. The temperature at which the temperature changed by half the difference in the baseline before and after the transition of the DSC curve was taken as the glass transition temperature. Heat resistance was evaluated on a three-level scale of × (poor), ○ (good), and ⊚ (excellent) according to the following criteria: ×: Glass transition temperature is less than 123°C; ○: Glass transition temperature is 123°C or higher but less than 125°C; ⊚: Glass transition temperature is 125°C or higher

[0038] (3) Impact Resistance Impact resistance was evaluated by an Izod test in accordance with JIS K7110. That is, ten unnotched test pieces, each 63.5 mm long, 12.7 mm wide, and 3.2 mm thick, obtained by polyester injection molding, were tested using a 4J hammer at 23°C and 50% relative humidity, and the number of pieces that did not break was counted. The tester used was an Izod impact tester manufactured by Ueshima Seisakusho Co., Ltd. Table 1 shows the number of pieces out of the ten that did not break. Impact resistance was evaluated on a two-level scale of x (poor) and ◯ (excellent) according to the following criteria: x: Breakage ◯: None of the pieces broke

[0039] (4) Overall Evaluation When there was a rating of x (poor) in the evaluations of (2) heat resistance and (3) impact resistance, the overall evaluation was rated as x (poor), and the rest was rated as o (excellent).

[0040] [Synthesis of Polyesters] The polyesters of the examples and comparative examples were synthesized as follows. (Example 1) A 30 L polyester production apparatus equipped with a packed column type rectification column, a partial condenser, a total condenser, a cold trap, a stirrer, a heating device, and a nitrogen inlet tube was charged with raw material monomers: 34.3 mol of dimethyl 2,6-naphthalenedicarboxylate, 11.4 mol of dimethyl terephthalate, 4.6 mol of 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 13.8 mol of 1,4-cyclohexanedimethanol, and 27.4 mol of ethylene glycol. 0.005 mol % of tetra-n-butoxytitanium and 0.001 mol % of potassium acetate were added relative to the total of dimethyl 2,6-naphthalenedicarboxylate and dimethyl terephthalate (total dicarboxylic acid components). The mixture was heated to 225°C under a nitrogen atmosphere to carry out a transesterification reaction. After the reaction conversion of the dicarboxylic acid component reached 90% or more, 0.025 mol % of germanium dioxide and 0.05 mol % of triethyl phosphate were added to the dicarboxylic acid component, and the temperature and pressure were gradually increased, and polycondensation was finally carried out at 280°C and 0.1 kPa or less. The reaction was terminated when an appropriate melt viscosity was achieved, yielding a polyester. The composition and content of the resulting polyester were analyzed by the above-mentioned method, and it was found to be 25 mol % of 2,6-naphthalenedicarboxylic acid structural units, 75 mol % of terephthalic acid structural units, 10 mol % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol structural units, 30 mol % of 1,4-cyclohexanedimethanol structural units, and 60 mol % of ethylene glycol structural units.

[0041] In Examples 2 to 6 and Comparative Examples 1 to 6, polyesters were produced in the same manner as in Example 1, except that raw material monomers were adjusted and charged to obtain the monomer ratios shown in Table 1. When the composition and content of the obtained polyesters were analyzed by the above-mentioned methods, it was found that the structural units and content ratios were as shown in Table 1.

[0042]

[0043] The meanings of the abbreviations in Table 1 are as follows: TMCD: 2,2,4,4-tetramethyl-1,3-cyclobutanediol CHDM: 1,4-cyclohexanedimethanol EG: ethylene glycol DMT: dimethyl terephthalate NDCM: dimethyl 2,6-naphthalenedicarboxylate

[0044] The results in Table 1 show that the polyesters of each Example have high heat resistance and impact resistance because the dicarboxylic acid structural units contain 72.5 mol % or more of 2,6-naphthalenedicarboxylic acid structural units and the diol structural units contain 27.5 mol % or more of 1,4-cyclohexanedimethanol structural units and 2,2,4,4-tetramethyl-1,3-cyclobutanediol structural units. On the other hand, the contents of the dicarboxylic acid structural units and diol structural units of each Comparative Example are outside the ranges of this embodiment, and therefore the polyesters are inferior in either heat resistance or impact resistance.

[0045] According to the present invention, a polyester and a baby bottle having high heat resistance and impact resistance can be provided.

Claims

1. A baby bottle formed using a polyester containing dicarboxylic acid structural units and diol structural units, wherein the dicarboxylic acid structural units contain 72.5 mol% or more of structural units derived from 2,6-naphthalenedicarboxylic acid and / or its ester derivatives, based on a total of 100 mol% of the dicarboxylic acid structural units, and the diol structural units contain 27.5 mol% or more of structural units derived from 1,4-cyclohexanedimethanol and structural units derived from 2,2,4,4-tetramethyl-1,3-cyclobutanediol, based on a total of 100 mol% of the diol structural units.

2. The baby bottle according to claim 1, wherein the dicarboxylic acid structural units contain structural units derived from 2,6-naphthalenedicarboxylic acid and / or its ester derivatives in an amount of 75 mol % or more per 100 mol % of the total dicarboxylic acid structural units.

3. The baby bottle according to claim 1 or 2, wherein the diol structural units contain 5 mol % or more of structural units derived from 2,2,4,4-tetramethyl-1,3-cyclobutanediol, based on a total of 100 mol % of the diol structural units.

4. The baby bottle according to claim 1 or 2, wherein the dicarboxylic acid structural units further contain structural units derived from terephthalic acid and / or an ester derivative thereof.

5. The baby bottle according to claim 1 or 2, wherein the diol structural units further contain structural units derived from ethylene glycol.

6. A polyester comprising dicarboxylic acid structural units and diol structural units, wherein the dicarboxylic acid structural units comprise, within a total of 100 mol % of the dicarboxylic acid structural units, 72.5 mol % or more of structural units derived from 2,6-naphthalenedicarboxylic acid and / or an ester derivative thereof, and the diol structural units comprise, within a total of 100 mol % of the diol structural units, 27.5 mol % or more of structural units derived from 1,4-cyclohexanedimethanol and structural units derived from 2,2,4,4-tetramethyl-1,3-cyclobutanediol.

Images