Abstract: Provided is a prefilled syringe comprising, as a resin constituting at least a barrel and a joint, a polyester resin that contains a diol unit having a cyclic acetal skeleton in an amount of from 1 to 30% by mol based on diol units and a dicarboxylic acid unit having a naphthalene skeleton in an amount of 70% by mol or more based on dicarboxylic acid units, and satisfies the following parameters: (i) a glass transition temperature of 110° C. or more measured with a differential scanning calorimeter, (ii) a moisture permeation coefficient of 1 g·mm/m2/day or less, and (iii) an oxygen permeation coefficient of 10 cc·mm/m2/day/atm or less.

Abstract: A polyester resin having a diol unit containing a unit derived from ethylene glycol and a unit derived from a diol represented by the following formula (I), and a dicarboxylic acid unit containing a unit derived from an aromatic dicarboxylic acid in an amount of 50 mol % or more; wherein the entire diol unit contains the unit derived from ethylene glycol in an amount of 40 to 99 mol %, and the unit derived from a diol represented by formula (I) in an amount of 1 to 60 mol %: wherein A represents an aromatic ring selected from the group consisting of benzene, naphthalene, anthracene, phenanthrene and pyrene; R1 represents a C1 to C12 alkyl group, a substituted or unsubstituted C6 to C12 aryl group or a halogen atom; n represents an integer of 0 to 4; and when plural R1s are present, R1s may be the same as or different from each other.

Abstract: An optical lens is obtained by injection-molding a polyester resin containing a diol unit containing from 40 to 99% by mol of a unit derived from ethylene glycol and from 1 to 60% by mol of a unit derived from a diol having from 3 to 16 carbon atoms, and a dicarboxylic acid unit containing 50% by mol or more of a unit derived from a naphthalenedicarboxylic acid.

Abstract: Disclosed is a glycol compound which is useful as a raw material and an intermediate for synthetic resins, additives for synthetic resins, medicines, cosmetics, food additives, surfactants and the like, further disclosed is a method for producing the compound. The above glycol compound is represented by the following Formula (1): wherein A represents a divalent linkage group comprising a condensed aromatic ring selected from the group consisting of naphthalene, anthracene, phenanthrene and pyrene; R represents an alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms or a halogen atom; n represents an integer of 0 to 4; and when n represents an integer of 2 to 4, plural R may be the same or different from each other.

Abstract: Disclosed is a glycol compound which is useful as a raw material and an intermediate for synthetic resins, additives for synthetic resins, medicines, cosmetics, food additives, surfactants and the like, further disclosed is a method for producing the compound. The glycol compound is represented by the following Formula (1): wherein R represents an alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms or a halogen atom; n represents an integer of 1 to 4; and when n represents an integer of 2 to 4, plural R may be the same or different from each other.

Abstract: The present invention relates to a polyester film produced by melt-extruding a polyester composed of a dicarboxylic acid unit and a diol unit, wherein 1 to 80 mol % of the diol unit is a unit containing a cyclic acetal skeleton, and the polyester film has an in-plane retardation of 20 nm or less at a wavelength of 550 nm. The polyester film is an optically isotropic polyester film which is easily produced by an extrusion-molding method and has an economical advantage. The polyester film is useful for production of optical members or optical products such as phase difference films, protective films for polarizing plates, light diffusion films, lens sheets, anti-reflection films and optical information recording media.

Abstract: An optical lens formed of a polyester resin having a high refractive index, a low Abbe number and good moldability is provided. The optical lens is obtained by injection-molding a polyester resin containing a diol unit containing from 40 to 99% by mol of a unit derived from ethylene glycol and from 1 to 60% by mol of a unit derived from a diol having from 3 to 16 carbon atoms, and a dicarboxylic acid unit containing 50% by mol or more of a unit derived from a naphthalenedicarboxylic acid.

Abstract: A prefilled syringe is provided that has high heat resistance, low adsorbability, low moisture permeability and low oxygen permeability. A prefilled syringe containing, as a resin constituting at least a barrel and a joint, a polyester resin that contains a diol unit having a cyclic acetal skeleton in an amount of from 1 to 30% by mol based on diol units and a dicarboxylic acid unit having a naphthalene skeleton in an amount of 70% by mol or more based on dicarboxylic acid units, and satisfies the following (i) to (iii): (i) a glass transition temperature of 110° C. or more measured with a differential scanning calorimeter, (ii) a moisture permeation coefficient of 1 g·mm/m2/day or less, and (iii) an oxygen permeation coefficient of 10 cc·mm/m2/day/atm or less.

Abstract: The present invention relates to a polyester film produced by melt-extruding a polyester composed of a dicarboxylic acid unit and a diol unit, wherein 1 to 80 mol % of the diol unit is a unit containing a cyclic acetal skeleton, and the polyester film has an in-plane retardation of 20 nm or less at a wavelength of 550 nm. The polyester film is an optically isotropic polyester film which is easily produced by an extrusion-molding method and has an economical advantage. The polyester film is useful for production of optical members or optical products such as phase difference films, protective films for polarizing plates, light diffusion films, lens sheets, anti-reflection films and optical information recording media.

Abstract: In the invention, a polyester resin comprising dicarboxylic acid constitutional units and diol constitutional units wherein 5 to 60 mol % of the diol constitutional units has a cyclic acetal skeleton is produced by a process comprising an oligomerization step and a polymerization step. In the oligomerization step, an ester having a limited acid value is transesterified with a diol having a cyclic acetal skeleton in the presence of a basic compound to obtain an oligomer. The oligomer is then polymerized in the subsequent polymerization step to increase the molecular weight.

Abstract: In the invention, a polyester resin having dicarboxylic acid constitutional units and diol constitutional units wherein 5 to 60 mol % of the diol constitutional units has a cyclic acetal skeleton is produced by a process including an oligomerization step and a polymerization step. In the oligomerization step, an ester having a limited acid value is transesterified with a diol having a cyclic acetal skeleton in the presence of a titanium compound to obtain an oligomer. The oligomer is then polymerized in the subsequent polymerization step to increase the molecular weight.

Abstract: The invention provides a thermoplastic resin composition which is excellent in transparency, heat resistance, resistance to chemicals, and mechanical strength as well as moldability, printability, etc. The thermoplastic resin composition containing a polycarbonate resin in an amount of 2 to 99.5 wt. % and a polyester resin in an amount of 98 to 0.5 wt. %, wherein the polyester resin (B) contains diol units each having a cyclic acetal skeleton in an amount of 20 to 60 mol % with respect to total diol structural units.

Abstract: Polyester resin composition (C) comprises polyester resin (A), which comprises polyester resin (l) comprising a diol unit having a cyclic acetal structure (CA) and a dicarboxylic acid unit having no CA, polyester resin (m) comprising a dicarboxylic acid unit having CA and a diol unit having no CA and/or polyester resin (n) comprising a diol unit having CA and a dicarboxylic acid unit having CA, and polyester resin (B) having no CA. The sum of the fraction of the dicarboxylic acid unit having CA in the entire dicarboxylic acid unit and the fraction of the diol unit having CA in the entire diol unit in composition (C) is 0.05% by mole or greater. The polyester resin compositions are excellent in transparency, melt viscoelasticity, heat resistance and moldability, and exhibit a samll crystallization rate.

Abstract: In the invention, a polyester resin having dicarboxylic acid constitutional units and diol constitutional units wherein 5 to 60 mol % of the diol constitutional units has a cyclic acetal skeleton is produced by a process including an oligomerization step and a polymerization step. In the oligomerization step, an ester having a limited acid value is transesterified with a diol having a cyclic acetal skeleton in the presence of a titanium compound to obtain an oligomer. The oligomer is then polymerized in the subsequent polymerization step to increase the molecular weight.

Abstract: In the invention, a polyester resin comprising dicarboxylic acid constitutional units and diol constitutional units wherein 5 to 60 mol % of the diol constitutional units has a cyclic acetal skeleton is produced by a process comprising an oligomerization step and a polymerization step. In the oligomerization step, an ester having a limited acid value is transesterified with a diol having a cyclic acetal skeleton in the presence of a basic compound to obtain an oligomer. The oligomer is then polymerized in the subsequent polymerization step to increase the molecular weight.

Abstract: The process of the present invention for producing a polyester resin comprising a dicarboxylic acid constitutional unit and a diol constitutional unit having a cyclic acetal skeleton comprises a step (1) of subjecting a diol (A) having a cyclic acetal skeleton and an ester (D) to transesterification reaction and a step (2) of mainly converting the resultant oligomer into a high polymer. The step (1) simultaneously satisfies the requirements (i) to (iv) as described in the specification. In the process of the present invention, the polyester resins having excellent moldability and mechanical properties are stably produced by a transesterification method which is less detrimental to environments.

Abstract: There is disclosed A polyester based resin composition (D) which comprises a polyamide resin (A) and a polyester resin (B), or a polyamide resin (A), a polyester resin (B) and a polyethylene terephthalate resin (C), characterized in that the polyester resin (B) is obtained by polycondensation of a dicarboxylic acid component containing 0.5 to 60 mol % of a dicarboxylic acid having a cyclic acetal skeleton and/or a diol component containing 0.5 to 60 mol % of a diol having a cyclic acetal skeleton, and that the blending proportions of the polyamide resin (A), the polyester resin (B) and the polyethylene terephthalate resin (C) are each in the range of 1 to 99% by weight, 1 to 99% by weight and 0 to 98% by weight, respectively on the basis of total sum weight of the components (A), (B) and (C). There is further disclosed a molded product (film, sheet, thin wall hollow container, etc.).

Abstract: The process of the present invention for producing a polyester resin comprising a dicarboxylic acid constitutional unit and a diol constitutional unit having a cyclic acetal skeleton comprises a step (1) of subjecting a diol (A) having a cyclic acetal skeleton and an ester (D) to transesterification reaction and a step (2) of mainly converting the resultant oligomer into a high polymer. The step (1) simultaneously satisfies the requirements (i) to (iv) as described in the specification. In the process of the present invention, the polyester resins having excellent moldability and mechanical properties are stably produced by a transesterification method which is less detrimental to environments.

Abstract: In the production method of the present invention, a copolyester of intended sublimable diol proportion is produced by the reaction of a dicarboxylic acid and/or an ester-forming derivative thereof with a sublimable diol and a non-sublimable diol with an increased conversion of the sublimable diol. Since the escape of the sublimable diol is effectively prevented, the process solves the problem of clogging pressure-reduced pipes, etc. of an apparatus for polyester resin production.

Abstract: Polyester resin composition (C) comprises polyester resin (A), which comprises polyester resin (l) comprising a diol unit having a cyclic acetal structure (CA) and a dicarboxylic acid unit having no CA, polyester resin (m) comprising a dicarboxylic acid unit having CA and a diol unit having no CA and/or polyester resin (n) comprising a diol unit having CA and a dicarboxylic acid unit having CA, and polyester resin (B) having no CA. The sum of the fraction of the dicarboxylic acid unit having CA in the entire dicarboxylic acid unit and the fraction of the diol unit having CA in the entire diol unit in composition (C) is 0.05% by mole or greater. The polyester resin compositions are excellent in transparency, melt viscoelasticity, heat resistance and moldability, and exhibit a samll crystallization rate.