JP2001342334A - Polyester resin composition and molded article composed of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester resin composition which excels in gas barrier properties, transparency, and heat resistance and, at the same time, suppresses the generation of acetaldehyde, and a molded article using the composition. SOLUTION: The polyester resin composition comprises 1-80 wt.% polyester pellets A having a dicarboxylic acid constituting unit to be derived from dicarboxylic acids containing terephthalic acid and isophthalic acid and a diol constituting unit to be derived from diols containing ethylene glycol and 1,3-bis(2- hydroxyethoxy)benzene with (i) a terephthalic acid constituting unit of 15-99.5 mol% and (ii) an isophthalic acid constituting unit of 0.5-85 mol%, and a 1,3-bis(2-hydroxyethoxy)benzene constituting unit of 0.5-75 mol% and having an intrinsic viscosity of 0.5-1.5 dl/g, a melting point (Tm: deg.C) which meets the formula: [1/527-0.0017.ln(1-(mI+mB)/200)-1-273<Tm<=265, and a density of 1350 kg/m3 and 99-20 wt.% repro-polyethylene terephthalate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin composition and a molded article comprising the composition, and more particularly, to a polyester resin composition excellent in gas barrier properties, transparency and heat resistance of the molded article, and a polyester resin composition thereof. Related to molded products.

[0002]

BACKGROUND OF THE INVENTION Saturated polyesters such as polyethylene terephthalate are widely used as containers such as bottles because of their excellent gas barrier properties, transparency and mechanical strength.

[0003] In particular, bottles obtained by biaxially stretch-blowing polyethylene terephthalate have excellent transparency, mechanical strength, heat resistance and gas barrier properties, and are used for filling beverages such as juices, soft drinks and carbonated drinks. Container (PET
Widely used as bottles).

[0004] Such a bottle is generally formed by injection molding a saturated polyester to form a preform having a plug portion and a body portion, and then inserting the preform into a mold having a predetermined shape and stretching the preform. It has been manufactured as a bottle having a mouthpiece and an elongated body by blow molding and stretching the body.

[0005] Among such polyester bottles,
In particular, polyester bottles used for beverages such as juices are required to have heat resistance that can cope with heat sterilization of the contents, so the bottles are usually heat-treated (heat-set) after blow molding to improve heat resistance. Let me.

In addition, the polyester bottle manufactured as described above has a non-stretched plug portion and is inferior in mechanical strength and heat resistance as compared with a stretched trunk portion.
For this reason, usually, the plug portion of the preform is heated and crystallized before blow molding, or the plug portion of the bottle obtained by blow molding is heated and crystallized, and the mechanical strength of the plug portion, Heat resistance etc. are improved.

In recent years, bottles produced from polyester resins (particularly, polyethylene terephthalate) have tended to be miniaturized.
Since the area in contact with the bottle body per unit volume is increased, the effect on the contents due to gas loss or permeation of oxygen from the outside becomes remarkable, and the storage period of the contents is reduced. For this reason, polyester resins are required to have better gas barrier properties than before.

[0008] As an attempt to improve the heat resistance and gas barrier properties of such a polyester resin, it has been proposed to blend polyethylene terephthalate with polyethylene isophthalate or the like (for example, Japanese Patent Publication No. HEI-Hei).
1-22302 gazette). However, in such a blend of polyethylene terephthalate and polyethylene isophthalate, acetaldehyde is generated at the time of melt-kneading at a high temperature performed to increase compatibility, or the taste of the content filled in the container is reduced, In addition, there are problems such as a decrease in transparency, and furthermore, polyethylene isophthalate adheres to the screw and burns due to long-term retention. In addition, when polyethylene isophthalate is amorphous, it is necessary to dry polyethylene terephthalate in a usual dryer, cool, blend polyethylene terephthalate and polyethylene isophthalate in a dry state, and mold, and drying and molding There were problems such as the cost of equipment required until the machine was put into operation, and the necessity of a larger space for installing the equipment.

For this reason, polyesters comprising a dicarboxylic acid component containing terephthalic acid as a main component, isophthalic acid and ethylene glycol have been proposed. However, heat resistance and gas barrier properties are not always sufficient, and acetaldehyde is not sufficient. May occur, more heat resistance,
There is a demand for a polyester resin composition having excellent gas barrier properties and generating less acetaldehyde.

In recent years, collected PET bottles and defective moldings have been recycled and used (for example, at least once, such as collected PET bottles and defective moldings). Polyethylene terephthalate that has passed through a molding machine in a heated and molten state is sometimes referred to as repropolyethylene terephthalate). However, molded articles obtained from such repropolyethylene terephthalate have problems such as insufficient transparency and, in some cases, affecting the contents. Therefore, such a method capable of effectively reusing repropolyethylene terephthalate has attracted attention in terms of effective use of resources.

[0011]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above prior art, and is intended to provide a polyester resin composition which is excellent in gas barrier properties, transparency and heat resistance and generates little acetaldehyde. It is intended to provide a molded article using the composition.

[0012]

SUMMARY OF THE INVENTION A polyester resin composition according to the present invention comprises [A] a dicarboxylic acid structural unit derived from a dicarboxylic acid containing terephthalic acid and isophthalic acid, ethylene glycol and 1,3-bis (2- (I) a diol structural unit derived from a diol containing (hydroxyethoxy) benzene, and (i) 15 to 99.5 mol% of a structural unit derived from terephthalic acid, based on all dicarboxylic acid structural units.
And the structural unit derived from isophthalic acid is 0.5 to
85 mol%, and (ii) based on all diol structural units,
25 to 9 structural units derived from ethylene glycol
9.5 mol%, 1,3-bis (2-hydroxyethoxy)
Structural unit derived from benzene is 0.5 to 75 mol%
The intrinsic viscosity is in the range of 0.5 to 1.5 dl / g, and the melting point (Tm (° C.)) measured by a differential scanning calorimeter satisfies the following general formula [I]; _{· ln (1- (m I +} m B) / 200)] -1 -273 <Tm ≦ 265 ... [I] ( wherein, m _I is a structural unit derived from isophthalic acid in the total dicarboxylic acid constitutional units % (Mol%), and m _B indicates the ratio (mol%) of the structural unit derived from 1,3-bis (2-hydroxyethoxy) benzene in all the diol structural units.) Density is 1350 kg / m ³ A polyester pellet consisting of the above polyester and [B] polyethylene terephthalate (repro polyethylene terephthalate) which has been passed through a molding machine at least once in a heated and molten state, wherein the polyester pellet [A] is 1 to 80% by weight, Characterized in that the polyethylene terephthalate [B] is in the range of 99 to 20% by weight I have.

The polyester pellet [A] preferably has a melting point (Tm (° C.)) satisfying the following general formula [I ']. [1 / 527-0.0017 · ln (1- (m _I + m _B ) / 200)] ^-1 -270 <Tm ≦ 265 ... [I '] The molded article according to the present invention comprises the above composition. Features.

Preferably, the molded product is a preform, a bottle or a sheet. The multilayer molded product according to the present invention is a multilayer molded product comprising an inner layer, an intermediate layer, and an outer layer, wherein the inner layer and the outer layer are composed of a resin having a polyethylene terephthalate resin as a main component, and the intermediate layer is composed of the composition described above. Wherein the intermediate layer is made of the polyester resin composition and the thickness of the intermediate layer is in the range of 10 to 70% of the container thickness.

It is preferable that the multilayer molded product is a preform, a bottle or a sheet.

[0016]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the polyester resin composition according to the present invention and a molded article using the composition will be described in detail.

[Polyester Resin Composition] The polyester resin composition according to the present invention comprises [A] polyester pellets and [B] repropolyethylene terephthalate.

Polyester Pellets [A] The polyester pellets used in the present invention contain 15 to 99.5 mol%, preferably 50 to 9 mol%, of structural units derived from terephthalic acid, based on all dicarboxylic acid structural units.
It is made of a polyester containing a constitutional unit derived from isophthalic acid in an amount of 0.5 to 85 mol%, preferably 1 to 50 mol%, in an amount of 9 mol%.

Such a polyester may contain a dicarboxylic acid structural unit other than isophthalic acid and terephthalic acid in an amount of less than 20 mol% as long as the object of the present invention is not impaired.

The other dicarboxylic acids which may be contained in an amount of less than 20 mol% include, specifically, phthalic acid (orthophthalic acid), 2,6-naphthalenedicarboxylic acid,
Aromatic dicarboxylic acids such as 7-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, azelaic acid, decanedicarboxylic acid, etc. Aliphatic dicarboxylic acids such as aliphatic dicarboxylic acids and cyclohexanedicarboxylic acid are exemplified.

These dicarboxylic acids may be ester derivatives thereof, or may be a combination of two or more. In addition, the diol constituent unit of such a polyester has a constituent unit derived from ethylene glycol in an amount of 25 to 99.5 mol% based on all diol constituent units,
Preferably 35 to 99.5 mol%, more preferably 5
In the range of 0 to 99.5 mol%, the structural unit derived from 1,3-bis (2-hydroxyethoxy) benzene is 0.5 to 10%.
It is preferably contained in the range of 75 mol%, preferably 0.5 to 65 mol%, more preferably 0.5 to 50 mol%.

Further, the polyester may contain a diol structural unit other than ethylene glycol and 1,3-bis (2-hydroxyethoxy) benzene in an amount of less than 15 mol% as long as the object of the present invention is not impaired. May be contained.

Other diols which may be contained in an amount of less than 15 mol% include diethylene glycol, triethylene glycol, tetraethylene glycol, trimethylene glycol, propylene glycol, butanediol, pentanediol, and the like. Aliphatic glycols such as neopentyl glycol, hexamethylene glycol, dodecamethylene glycol, alicyclic glycols such as cyclohexane dimethanol, 1,2-bis (2
Glycols containing an aromatic group such as -hydroxyethoxy) benzene, 1,4- (2-hydroxyethoxy) benzene,
Examples include aromatic diols such as bisphenols, hydroquinone, and 2,2-bis (4-β-hydroxyethoxyphenyl) propane.

These diols may be ester derivatives thereof or may be a combination of two or more. As other diols, diethylene glycol is preferable among these.

Further, such a polyester is derived from a polyfunctional carboxylic acid having three or more carboxyl groups or a polyhydric alcohol having three or more hydroxy groups as long as the object of the present invention is not impaired. A unit derived from a polyfunctional carboxylic acid and / or a unit derived from a polyhydric alcohol may be independently added to the dicarboxylic acid unit in an amount of 0.01 to 100 mol%. ~ 5 mol%, preferably 0.05
To 3 mol%, more preferably 0.1 to 1.5 mol%.

The intrinsic viscosity of such a polyester measured in o-chlorophenol at 25 ° C. is 0.50 to 1.5 dl /
g, preferably 0.60 to 1.5 dl / g, more preferably 0.7 to
It is desirable to be in the range of 0.9 dl / g.

Further, such a polyester has a melting point (Tm (° C.)) measured by a differential scanning calorimeter which satisfies the following general formula [I]. [1 / 527-0.0017 · ln (1- (m _I + m _B ) / 200)] ⁻¹ -273 <Tm ≦ 265… [I] (where m _I is isophthalic acid in all dicarboxylic acid constituent units) Ratio (mol%) of the structural unit derived from the above, and m _B indicates the ratio (mol%) of the structural unit derived from 1,3-bis (2-hydroxyethoxy) benzene in all the diol structural units. The melting point (Tm (° C.)) is further represented by the following general formula:
It is desirable to satisfy [I '].

[1 / 527-0.0017 · ln (1- (m _I + m _B ) / 200)] ⁻¹ -270 <Tm ≦ 265 ... [I ′] In the above general formulas [I] and [I ′] , Preferably Tm is 257
C. or lower, more preferably 254.degree. C. or lower.

[0029] Such a polyester has a density of 1350 kg.
/ m ³ or more, preferably 1355 kg / m ³ or more, more preferably 13
60 kg / m ³ or more, more preferably at 1380kg / m ³ or more.

Such a polyester has a heat of crystallization at the time of temperature rise of usually 5 J / g or more, preferably 7 to 4 J / g.
It is desirable to be in the range of 0 J / g. The polyester pellets had an acetaldehyde content of 20%.
It is preferably at most ppm, particularly preferably at most 10 ppm.

The size and shape of such a polyester pellet are not particularly limited, and are appropriately selected according to the use of the pellet to be used. Examples of the shape include a columnar shape, an elliptical columnar shape, a spherical shape, and an elliptical spherical shape. The size of the pellets is not particularly limited, but generally has an average particle size of about 2.0 to 5.0 mm.

Such polyester pellets can be produced by the following production methods (1) and (2). Also, polyester pellets, if necessary, additives usually added to the polyester, for example, a coloring agent,
An antioxidant, an oxygen absorber, an ultraviolet absorber, an antistatic agent, and a flame retardant may be contained. Also, if necessary, PET
May be arbitrarily blended.
Furthermore, polyester pellets, if necessary,
A resin other than polyester, for example, polyethylene, ionomer, polypropylene, or polyester elastomer may be contained.

Repropolyethylene terephthalate [B] The [B] repropolyethylene terephthalate used in the present invention is polyethylene terephthalate which has been passed through a molding machine at least once in a heated and molten state. Such repropolyethylene terephthalate may have a heat history of pelletizing by applying heat again. In this way, the process of “passing the polyethylene terephthalate through a molding machine in a heated and molten state” is performed by heating and melting pellets (chips) made of the raw material polyethylene terephthalate and forming them into a desired shape such as a preform or a hollow molded container. Will be Further, as such [B] repropolyethylene terephthalate, a recovered polyethylene terephthalate container or a poorly molded product can be used.

The polyester composition according to the present invention contains 1 to 80% by weight of the polyester pellets [A] when the total of the polyester pellets [A] and repropolyethylene terephthalate [B] is 100% by weight. Preferably 5-70% by weight, repropolyethylene terephthalate
[B] is 99 to 20% by weight, preferably 95 to 30% by weight
Is desirably within the range.

Hue adjuster The polyester composition according to the present invention may contain a hue adjuster, if necessary. As the hue adjusting agent, organic pigments, inorganic pigments, organic dyes, inorganic dyes, and the like are used, and those having a hue of blue or red are particularly preferable.
Specifically, Solvent Blue 104, Pigment Red 263, Sol
vent Red 135, Pigment Blue 29, Pigment Blue 15: 1,
Pigment Blue 15: 3, Pigment Red 187, Pigment Violet
19 (These examples are the Color Index
name. ).

This hue adjuster can be used alone or in combination of two or more. These hue adjusters are usually used in an amount of 0.05 to 100 ppm, preferably 0.1 to 50 ppm, based on the total weight of the polyester pellet [A] and repropolyethylene terephthalate [B].
Desirably, it is contained in the composition in the amount of ppm.

Preparation of Composition The polyester resin composition according to the present invention is, for example,
It is prepared by blending [A] polyester pellets, [B] repropolyethylene terephthalate, and if necessary, a hue adjuster, and melt-kneading at 260 to 310 ° C. for 30 to 300 seconds. The blend after kneading,
It is pelletized by an extruder or the like. The average particle size of the pellets is desirably 2.0 to 5.0 mm.

The hue adjusting agent may be added to the polyester pellets in advance, or may be added to the polyester pellets after being mixed with the repropolyethylene terephthalate. Further, the polyester pellet [A] and the repropolyethylene terephthalate [B ] May be mixed when blended.

Further, the polyester composition according to the present invention may contain an antioxidant, an oxygen absorber, an ultraviolet absorber, an antistatic agent and a flame retardant, if necessary. Such a polyester-based resin composition may be blended with other resins and additives, if necessary, in a preform, a bottle,
It can be used as various molding materials such as films and sheets.

Next, a preferred method for producing the polyester pellet [A] used in the present invention will be described. [Production Method (1) of Polyester Pellets [A]] The polyester pellets [A] used in the present invention are, for example, [a] polyethylene terephthalate before solid phase polymerization having an intrinsic viscosity of 0.3 to 0.8 dl / g; 99-20% by weight and [b] the intrinsic viscosity
A polyethylene isophthalate copolymer before solid phase polymerization of 0.3 to 0.9 dl / g; 1 to 80% by weight, and after blending, pelletizing, crystallizing, and preferably further solid phase polymerizing. Manufactured.

Polyethylene terephthalate [a] The polyethylene terephthalate [a] used in the present invention
Is composed of a dicarboxylic acid unit derived from terephthalic acid or its ester derivative, and a diol unit derived from ethylene glycol or its ester derivative.

When the dicarboxylic acid unit of the polyethylene terephthalate [a] is 100 mol%,
80 mol% or more of terephthalic acid units, preferably 85 to 85 mol%
It is contained in an amount of 100 mol%.

Examples of other dicarboxylic acids which may be contained in an amount of 20 mol% or less include phthalic acid (orthophthalic acid), isophthalic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalene. Aromatic dicarboxylic acids such as dicarboxylic acid, 2,5-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid,
Examples include aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, sebacic acid, azelaic acid, and decanedicarboxylic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid.

These dicarboxylic acids may be ester derivatives or a combination of two or more. As the other dicarboxylic acid, isophthalic acid is preferable among them.

When the diol unit of polyethylene terephthalate [a] is 100 mol%, the ethylene glycol unit is at least 80 mol%, preferably 85 mol%.
Desirably, it is contained in an amount of about 100 mol%.

Other diols which may be contained in an amount of not more than 20 mol% include diethylene glycol, triethylene glycol, tetraethylene glycol, trimethylene glycol, propylene glycol, butanediol, pentanediol, and the like. Aliphatic glycols such as neopentyl glycol, hexamethylene glycol, dodecamethylene glycol, alicyclic glycols such as cyclohexane dimethanol, 1,2-bis (2
Glycols containing aromatic groups such as (-hydroxyethoxy) benzene, 1,3-bis (2-hydroxyethoxy) benzene, 1,4- (2-hydroxyethoxy) benzene, bisphenols, hydroquinone, 2,2-bis And aromatic diols such as (4-β-hydroxyethoxyphenyl) propane.

These diols may be ester derivatives, and these diols may be a combination of two or more. As other diols, diethylene glycol, cyclohexanedimethanol and the like are preferable among these.

Further, the polyethylene terephthalate used in the present invention may be derived from a polyfunctional carboxylic acid having three or more carboxyl groups or a polyhydric alcohol having three or more hydroxy groups as long as the object of the present invention is not impaired. May be contained, for example, trimesic acid, polyfunctional carboxylic acids such as pyromellitic anhydride, glycerin, 1,1,1-trimethylolethane, 1,1,1
It may contain units derived from polyhydric alcohols such as 1-trimethylolpropane, 1,1,1-trimethylolmethane, and pentaerythritol.

The polyethylene terephthalate [a] used in the present invention is substantially linear, which is confirmed by the fact that the polyethylene terephthalate [a] is dissolved in o-chlorophenol.

The polyethylene terephthalate [a] used in the present invention has an intrinsic viscosity [η] measured at 25 ° C. in o-chlorophenol of 0.3 to 0.8 dl / g, preferably 0.35 to 0.8 dl / g.
It is desirably 0.75 dl / g, which is after the completion of liquid phase polymerization and before solid phase polymerization.

The melting point of polyethylene terephthalate [a] measured by a differential scanning calorimeter (DSC, heating rate: 10 ° C./min) is usually from 210 to 265 ° C., preferably from 220 to 260 ° C. The transition temperature is usually 50 to 120 ° C., preferably 6
Desirably, the temperature is 0 to 100 ° C.

Such polyethylene terephthalate
[a] may be pre-crystallized if necessary. The pre-crystallization is usually carried out at 100 to 220 ° C, preferably at 130 to 200 ° C, for 1 hour.
It can be performed by heating for about 360 minutes.

Such polyethylene terephthalate
[a] can be produced by a conventionally known method. For example, after the dicarboxylic acid and diol are directly esterified, the presence of a polycondensation catalyst such as a germanium compound such as germanium dioxide, an antimony compound such as antimony trioxide and antimony acetate, and a titanium compound such as titanium tetraalkoxide is present. Performing melt polycondensation below, or dicarboxylic acid ester and diol, titanium tetrabutoxide, titanium alkoxide such as titanium isopropoxide, cobalt acetate, zinc acetate,
It can be produced by performing a transesterification reaction in the presence of a transesterification catalyst such as a metal acetate such as manganese acetate and calcium acetate. As the transesterification catalyst, titanium tetrabutoxide and zinc acetate are desirable. afterwards,
Germanium compounds such as germanium dioxide, antimony trioxide, antimony compounds such as antimony acetate,
It can be produced by melt polycondensation in the presence of a polycondensation catalyst such as a titanium compound such as titanium tetraalkoxide. Such a polycondensation catalyst is 0.0005 to 0.1 part by weight, preferably 100 parts by weight of the total of the dicarboxylic acid or dicarboxylic acid ester and the diol, preferably
Desirably, it is contained in an amount of 0.001 to 0.05 parts by weight.

Polyethylene isophthalate copolymer [b] The polyethylene isophthalate copolymer [b] used in the present invention comprises a dicarboxylic acid structural unit derived from a dicarboxylic acid containing terephthalic acid and isophthalic acid, and ethylene glycol. And diol constituent units derived from diols containing 1,3-bis (2-hydroxyethoxy) benzene.

The dicarboxylic acid structural unit is such that the structural unit derived from isophthalic acid is 50 to 98 mol%, preferably 60 to 95 mol%, based on all dicarboxylic acid structural units.
In the range, the structural unit derived from terephthalic acid is represented by 2
The content is preferably in the range of ５０50 mol%, preferably in the range of ５〜40 mol%.

Further, such a polyethylene isophthalate copolymer [b] may contain a dicarboxylic acid structural unit other than isophthalic acid and terephthalic acid in an amount of less than 15 mol% as long as the object of the present invention is not impaired. It may be contained.

Examples of other dicarboxylic acids which may be contained in an amount of less than 15 mol% include phthalic acid (orthophthalic acid), 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid,
Aromatic rings such as aromatic dicarboxylic acids such as diphenyldicarboxylic acid and diphenoxyethanedicarboxylic acid, aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, sebacic acid, azelaic acid and decanedicarboxylic acid, and cyclohexanedicarboxylic acid. Group dicarboxylic acids and the like.

These dicarboxylic acids may be ester derivatives thereof or may be a combination of two or more. The diol constituent unit is a constituent unit derived from ethylene glycol in a range of 15 to 99 mol%, preferably 15 to 90 mol%, more preferably 20 to 88 mol%, based on all diol constituent units. , 1,3-
It is preferable to contain a structural unit derived from bis (2-hydroxyethoxy) benzene in the range of 1 to 85 mol%, preferably 10 to 85 mol%, more preferably 12 to 80 mol%.

Further, the polyethylene isophthalate copolymer [b] used in the present invention may be ethylene glycol or 1,3-diene as long as the object of the present invention is not impaired.
Diol structural units other than bis (2-hydroxyethoxy) benzene may be contained in an amount of less than 15 mol%.

Examples of other diols which may be contained in an amount of less than 15 mol% include diethylene glycol, triethylene glycol, tetraethylene glycol, trimethylene glycol, propylene glycol, butanediol, pentanediol, Aliphatic glycols such as neopentyl glycol, hexamethylene glycol, dodecamethylene glycol, alicyclic glycols such as cyclohexane dimethanol, 1,2-bis (2
Glycols containing an aromatic group such as -hydroxyethoxy) benzene, 1,4- (2-hydroxyethoxy) benzene,
Examples include aromatic diols such as bisphenols, hydroquinone, and 2,2-bis (4-β-hydroxyethoxyphenyl) propane.

These diols may be an ester derivative thereof or a combination of two or more. As other diols, diethylene glycol is preferable among these.

Further, the polyethylene isophthalate copolymer [b] used in the present invention may be the polyethylene terephthalate [a] as long as the object of the present invention is not impaired.
May contain a unit derived from a polyfunctional carboxylic acid having three or more carboxyl groups or a polyhydric alcohol having three or more hydroxy groups, specifically, a polyfunctional carboxylic acid. A unit derived from an acid and / or a unit derived from a polyhydric alcohol,
Independently with respect to 100 mol% of dicarboxylic acid units, 0.0
It may be contained in an amount of 5 to 0.4 mol%, preferably 0.1 to 0.35 mol%, more preferably 0.2 to 0.35 mol%.

The intrinsic viscosity [η] of the polyethylene isophthalate copolymer [b] used in the present invention measured in o-chlorophenol at 25 ° C. is 0.3 to 0.9 dl /.
g, preferably 0.35 to 0.85 dl / g, after completion of liquid phase polymerization and before solid phase polymerization.

The glass transition temperature of the polyethylene isophthalate copolymer measured by a differential scanning calorimeter (DSC, heating rate: 10 ° C./min) is usually 40 to 120 ° C., preferably 50 to 100 ° C. It is desirable.

The polyethylene isophthalate copolymer [b] used in the present invention may be pre-crystallized, if necessary, as in the case of the polyethylene terephthalate [a]. Such a polyethylene isophthalate copolymer can be produced by a conventionally known method.For example, after directly diesterifying the dicarboxylic acid and the diol, a germanium compound such as germanium dioxide, antimony trioxide, Melt polycondensation in the presence of a polycondensation catalyst such as an antimony compound such as antimony acetate or a titanium compound such as titanium tetraalkoxide,
Alternatively, a transesterification reaction between a dicarboxylic acid ester and a diol in the presence of a transesterification catalyst such as titanium alkoxides such as titanium isopropoxide and titanium tetrabutoxide and metal acetates such as cobalt acetate, zinc acetate, manganese acetate and manganese acetate. I do. As the transesterification catalyst, titanium tetrabutoxide and zinc acetate are desirable. Thereafter, it can be produced by melt polycondensation in the presence of a polycondensation catalyst such as a germanium compound such as germanium dioxide, antimony trioxide, an antimony compound such as antimony acetate, and a titanium compound such as titanium tetraalkoxide. it can.

Polyester Blend The above-mentioned polyethylene terephthalate [a] and polyethylene isophthalate copolymer [b] were prepared by mixing (i) 15 to 99.000 structural units derived from terephthalic acid with respect to all dicarboxylic acid structural units. 5 mol%, the constitutional unit derived from isophthalic acid is 0.5 to 85 mol%, and (ii) the constitutional unit derived from ethylene glycol is 25 to 99.5 mol based on all the diol constitutional units. %, 1,3-bis (2
(Hydroxyethoxy) benzene is blended so that the constitutional unit derived from benzene is 0.5 to 75 mol%.

Specifically, the polyethylene terephthalate [a]; 99 to 20% by weight, preferably 99 to 40% by weight, more preferably 98 to 50% by weight, and the polyethylene isophthalate copolymer [b]; 1 to 80% by weight, preferably 1 to 60% by weight, more preferably 2 to
It is desirable to blend with 50% by weight.

After blending the polyethylene terephthalate [a] and the polyethylene isophthalate copolymer [b] so as to have the above-mentioned composition, the blend was heated at 260 to 310 ° C.
This is performed by melt-kneading for 2 to 300 seconds. The kneaded blend is formed into chips (pelletized) by an extruder or the like. The average particle size of the pellet is
Preferably it is 2.0 to 5.0 mm.

As described above, polyethylene terephthalate
When blending [a] and the polyethylene isophthalate copolymer [b], a transesterification catalyst, a lubricant and the like may be added as necessary.

Examples of the transesterification catalyst include germanium dioxide, antimony trioxide, antimony acetate, manganese acetate, magnesium acetate, cobalt acetate, calcium acetate, zinc acetate, titanium tetrabutoxide and the like. Such transesterification catalysts can be used in blend 100
It is desirable that it be contained in an amount of 0.0005 to 0.1 part by weight, preferably 0.001 to 0.05 part by weight, based on part by weight.

Specific examples of the lubricant include magnesium stearate and calcium stearate.
Such a lubricant is used for 100 parts by weight of the blend.
0.0005 to 0.1 parts by weight, preferably 0.001 to 0.1
It may be externally added in an amount of 0.05 parts by weight.

The temperature of the obtained blend was raised to the crystallization temperature (Tc
c) is preferably 190 ° C or lower, preferably 180 ° C or lower, more preferably 120 to 170 ° C. In addition, the temperature rise crystallization temperature (Tcc) is measured as follows.

Using a Perkin-Elmer DSC-7 differential scanning calorimeter, a sample of about 10 mg from the center of a polyester blend pellet dried at about 140 ° C. under a pressure of about 5 mmHg for about 5 hours or more was used. It is sealed in a liquid aluminum pan under a nitrogen atmosphere and measured. The measurement conditions were as follows: first, the temperature was raised rapidly from room temperature at a rate of 320 ° C./min, and the mixture was melted and held at 290 ° C. for 10 minutes. Thereafter, the peak temperature of the exothermic peak detected when the temperature is raised at a rate of 10 ° C./min is determined.

The intrinsic viscosity of the obtained blend at 25 ° C. in o-chlorophenol is 0.3 to 0.9 dl /
g, preferably 0.35 to 0.85 dl / g. Crystallization of the blend The pellets of the blend thus obtained are then crystallized.

The crystallization is performed by drying the blend in a dry state at a temperature from the glass transition temperature (Tg) to a temperature lower than the melting point, preferably Tg.
At a temperature 20 ° C. higher and 40 ° C. or lower than the melting point,
It is performed by holding for 1 to 300 minutes, preferably for 5 to 200 minutes. Specifically, it is carried out by heating to 80 to 210 ° C, preferably 100 to 180 ° C.

Crystallization can be performed in air or in an inert atmosphere. The crystallized polyester blend preferably has a crystallinity of 20 to 50%.

In such crystallization, the so-called solid state polymerization reaction of polyester does not proceed, and the intrinsic viscosity of the polyester blend after crystallization is almost the same as the intrinsic viscosity of the polyester blend before crystallization. Yes, the difference between the intrinsic viscosity of the polyester blend after crystallization and the intrinsic viscosity of the polyester blend before crystallization is usually 0.0
It is 6 dl / g or less.

By crystallizing the polyester blend in this way, the content of acetaldehyde contained in the polyester can be reduced. In the present invention, the crystallized blend may be subjected to solid-phase polymerization as needed. (Note that crystallization before solid-phase polymerization is sometimes referred to as pre-crystallization.) Solid-phase polymerization is usually performed at 180 to 230 ° C, preferably at 19 to 230 ° C.
Performed at 0-220 ° C. In addition, at the time of solid-phase polymerization, it is desirable that the pellets of the blend are dried. Therefore, the pellets of the blend may be dried at 80 to 180 ° C. in advance.

The thus obtained polyester pellet has an intrinsic viscosity of 0.5 to 1.5 dl / g, preferably 0.6 to 1.5 dl / g, measured in o-chlorophenol at 25 ° C.
-1.5 dl / g, more preferably 0.6-1.2 d
1 / g, preferably 1.1 to 2.5 times, preferably 1.2 to 2.0 times, the intrinsic viscosity of the blend before solid phase polymerization. The polyester pellets thus obtained may be subjected to a hot water treatment. Hot water treatment converts the obtained polyester pellets to 70
It is performed by immersing in hot water of ~ 120 ° C for 1 to 360 minutes. The catalyst used during the polyester polycondensation reaction can be deactivated by the hot water treatment.

The polyester pellets obtained by such a production method may be used, if necessary, with the above-mentioned hue adjuster, an additive usually added to polyester, such as an antioxidant, an oxygen absorber, an ultraviolet absorber, It may contain an inhibitor and a flame retardant.

[Production Method of Polyester Pellets [A]]
(2)] The polyester pellet [a] used in the present invention.
For example, [c] polyethylene terephthalate after solid-phase polymerization having an intrinsic viscosity of 0.5 to 1.5 dl / g;
0% by weight and [b] a polyethylene isophthalate copolymer having an intrinsic viscosity of 0.3 to 0.9 dl / g before solid phase polymerization;
% By weight, and after the blend is pelletized, crystallized, and preferably further produced by solid-phase polymerization.

[C] Polyethylene terephthalate The polyethylene terephthalate used in the present invention [c]
Is composed of a dicarboxylic acid unit derived from terephthalic acid or its ester derivative, and a diol unit derived from ethylene glycol or its ester derivative.

When the dicarboxylic acid unit of this polyethylene terephthalate [c] is 100 mol%,
80 mol% or more of terephthalic acid units, preferably 85 to 85 mol%
Desirably, it is contained in an amount of 100 mol%.

Examples of other dicarboxylic acids which may be contained in an amount of 20 mol% or less include those similar to those exemplified for the polyethylene terephthalate [a], and isophthalic acid is particularly preferred. .

The diol unit of the polyethylene terephthalate [c] is 80 mol% or more, preferably 85 mol%, when the unit is 100 mol%.
Desirably, it is contained in an amount of about 100 mol%.

As other diols which may be contained in an amount of 20 mol% or less, the same diols as those exemplified for the above-mentioned polyethylene terephthalate [a] can be mentioned. In particular, diethylene glycol, cyclohexane dimethanol Are preferred.

The polyethylene terephthalate [c] used in the present invention may be a polyfunctional carboxylic acid having three or more carboxyl groups or a polyvalent carboxylic acid having three or more hydroxy groups as long as the object of the present invention is not impaired. It may contain units derived from alcohols, for example, trimesic acid, polyfunctional carboxylic acids such as pyromellitic anhydride, glycerin, 1,1,1-trimethylolethane,
It may contain units derived from polyhydric alcohols such as 1,1,1-trimethylolpropane, 1,1,1-trimethylolmethane, and pentaerythritol.

The polyethylene terephthalate [c] used in the present invention is substantially linear, which is confirmed by the fact that the polyethylene terephthalate [c] is dissolved in o-chlorophenol.

The polyethylene terephthalate [c] used in the present invention has an intrinsic viscosity [η] measured at 25 ° C. in o-chlorophenol of 0.5 to 1.5 dl / g, preferably 0.6 to 1.5 dl / g.
It is desirably 1.1 dl / g, after solid phase polymerization.

The melting point of polyethylene terephthalate [c] measured with a differential scanning calorimeter (DSC, heating rate 10 ° C./min) is usually 230 to 270 ° C., preferably 240 to 270 ° C.
260 ° C., and the glass transition temperature is usually 58-75.
C, preferably 60-70C.

Such polyethylene terephthalate can be produced by a conventionally known method. For example, after directly diesterifying the dicarboxylic acid and diol, a germanium compound such as germanium dioxide, antimony trioxide, Antimony compounds such as antimony acetate, melt polycondensation in the presence of a polycondensation catalyst such as a titanium compound such as titanium tetraalkoxide, or an ester of a dicarboxylic acid and a diol,
The transesterification reaction is performed in the presence of a transesterification catalyst such as titanium alkoxide such as titanium isopropoxide and titanium tetrabutoxide and metal acetate such as cobalt acetate, zinc acetate, manganese acetate, and calcium acetate. As the transesterification catalyst, titanium tetrabutoxide and zinc acetate are desirable. After that, it is melt-polycondensed in the presence of a polycondensation catalyst such as germanium compounds such as germanium dioxide, antimony trioxide, antimony compounds such as antimony acetate, and titanium compounds such as titanium tetraalkoxide, and then solid-phase polymerized. Can be manufactured. The solid state polymerization is carried out by heating the melt polycondensate at a temperature of usually 180 to 230 ° C, preferably 190 to 220 ° C. At the time of solid phase polymerization, the melt polycondensate is desirably dried. Therefore, the melt polycondensate may be dried at 80 to 180 ° C. in advance.

Polyethylene isophthalate copolymer [b] The polyethylene isophthalate copolymer is composed of a dicarboxylic acid structural unit derived from a dicarboxylic acid containing terephthalic acid and isophthalic acid, ethylene glycol and 1,3-bis
(2-hydroxyethoxy) benzene and a diol structural unit derived from a diol containing benzene, and the same polyethylene isophthalate copolymer [b] exemplified in the above-mentioned production method (1) is used.

Polyester Blend The above polyethylene terephthalate [c] and polyethylene isophthalate copolymer [b] were prepared by mixing (i) the structural units derived from terephthalic acid with 15 to 99. 5 mol%, the constitutional unit derived from isophthalic acid is 0.5 to 85 mol%, and (ii) the constitutional unit derived from ethylene glycol is 25 to 99.5 mol based on all the diol constitutional units. %, 1,3-bis (2
(Hydroxyethoxy) benzene is blended so that the constitutional unit derived from benzene is 0.5 to 75 mol%.

Specifically, the above polyethylene terephthalate [c]; 99 to 20% by weight, preferably 99 to 40% by weight, more preferably 98 to 50% by weight, and the above polyethylene isophthalate copolymer [b]; 1 to 80% by weight, preferably 1 to 60% by weight, more preferably 2 to
50% by weight.

After blending the polyethylene terephthalate [c] and the polyethylene isophthalate copolymer [b] so as to have the above composition, the blend is prepared at 260 to 310 ° C. and 30 to 300.
This is performed by melt-kneading for seconds. The blend after kneading is pelletized by an extruder or the like. The average particle size of the pellets is preferably 2.0 to 5.0 mm.

As described above, polyethylene terephthalate
When blending [c] with the polyethylene isophthalate copolymer [b], if necessary, a transesterification catalyst, a lubricant and the like may be added in the same manner as in the production method (1).

The intrinsic viscosity of the obtained blend measured in o-chlorophenol at 25 ° C. is 0.3 to 0.9 dl /
g, preferably 0.35 to 0.85 dl / g.
The resulting blend has a heated crystallization temperature (Tcc) of 17
0 ° C or lower, preferably 160 ° C or lower, more preferably 1 ° C or lower.
It is preferably from 00 to 155 ° C.

Crystallization of the blend The pellets of the blend thus obtained are then crystallized. Crystallization is performed by drying the blend at a temperature below the glass transition temperature (Tg) to the melting point, preferably 20 ° C. above the Tg and 40 ° C. or more below the melting point.
It is carried out by holding for 300 minutes, preferably for 5 to 200 minutes. Specifically, it is carried out by heating to 80 to 210 ° C, preferably 100 to 180 ° C. Such crystallization can be performed in air or in an inert atmosphere.

The crystallized polyester blend is
It is desirable that the crystallinity be 20 to 50%. In addition,
In such crystallization, the so-called polyester solid-state polymerization reaction does not proceed, and the intrinsic viscosity of the polyester after crystallization is almost the same as the intrinsic viscosity of the polyester before crystallization, and the intrinsic viscosity of the polyester after crystallization. The difference between the viscosity and the intrinsic viscosity of the polyester before crystallization is usually 0.06 dl / g or less.

After crystallization, the pellets may be subjected to solid phase polymerization, if necessary. The solid phase polymerization is carried out usually at 180 to 230 ° C, preferably at 190 to 220 ° C, as in the above-mentioned production method (1). At the time of solid phase polymerization, it is desirable that the pellets of the blend are dried, and therefore, the pellets of the blend may be dried at 80 to 180 ° C. in advance.

The polyester pellets thus obtained may be subjected to a hot water treatment in the same manner as in the above-mentioned production method (1). Hydrothermal treatment, the obtained solid-phase polymer, 70-
It is performed by immersing in hot water of 120 ° C. for 1 to 360 minutes.

As described above, the polyester pellets may contain, if necessary, a hue adjuster, an additive usually added to polyester, for example, an antioxidant, an oxygen absorber,
It may contain an ultraviolet absorber, an antistatic agent and a flame retardant.

[Polyester molded article] The molded article according to the present invention comprises the polyester resin composition described above. As a molded article, a preform, a bottle or a sheet is suitable.

A molded article obtained from such a polyester resin composition according to the present invention uses a resin composition having excellent gas barrier properties containing isophthalic acid, 1,3-bis (hydroxyethoxy) benzene and the like. Therefore, it is superior in gas barrier properties as compared with a conventional molded product made of polyethylene terephthalate.

Further, a molded product having excellent transparency can be obtained as compared with a product using simply recovered polyethylene terephthalate or a defective molded product (repropolyethylene terephthalate).

The polyester resin composition according to the present invention can be suitably applied to a multilayer molded product. In such a multilayer molded article, at least one layer only needs to be formed from the polyester resin composition according to the present invention, and all the layers are formed from the polyester resin composition according to the present invention. Is also good.

In particular, when used for food applications, the multilayer molded product is a multilayer molded product comprising an inner layer, an intermediate layer, and an outer layer, wherein the inner layer and the outer layer are formed of a resin layer mainly composed of a polyethylene terephthalate resin. Preferably, the intermediate layer is made of the polyester resin composition.
In such a multilayer molded product, it is desirable that the thickness of the intermediate layer is in the range of 10 to 70%, preferably 10 to 60%, more preferably 15 to 50% of the container thickness.

The polyethylene terephthalate resin constituting the inner layer and the outer layer preferably has an intrinsic viscosity (hereinafter, referred to as IV) of 0.6 or more from the viewpoint of gas barrier properties and tensile strength. The resin constituting the inner layer and the outer layer may include polyethylene terephthalate, polyesters such as polyethylene isophthalate and polyethylene naphthalate, polyamides such as nylon 6, ethylene / vinyl acetate copolymer, and the like.

In such a multilayer molded product, first, a resin mainly composed of polyethylene terephthalate constituting an inner layer is injected by a main cylinder, and then the timing is slightly shifted to make a polyester resin composition constituting an intermediate layer. It can be made by injecting the object by means of a secondary cylinder and finally also by injecting polyethylene terephthalate by means of a main cylinder.

Further, since the intermediate layer does not come into contact with the contents at all, even if the intermediate layer is made of a resin composition containing repropolyethylene terephthalate such as a recovered polyethylene terephthalate container, the contents are not affected.

Since the resin composition used for the intermediate layer is a resin having excellent gas barrier properties including isophthalic acid, 1,3-bis (hydroxyethoxy) benzene, etc., a conventional polyethylene terephthalate single-piece molded product is used. Compared to
The obtained multilayer molded article has excellent gas barrier properties.

[0112] Such a multilayer molded product includes a preform,
Bottles or sheets are preferred. Bottles made from such multilayer molded articles have excellent gas barrier properties, transparency and heat resistance. Further, since the amount of acetaldehyde generated is small, the taste of contents such as juice does not decrease. In addition, since the intermediate layer does not directly contact the contents, it is excellent in hygiene.

[0113]

According to the polyester resin composition of the present invention, since repropolyethylene terephthalate is used, the production cost can be reduced. Moreover, recovered polyester can be reused in such repropolyethylene terephthalate, which is effective in preventing bottle pollution and disposal of waste bottles.

Further, since the polyester resin composition according to the present invention contains components having excellent gas barrier properties such as isophthalic acid and 1,3-bis (hydroxyethoxy) benzene, polyethylene terephthalate alone is used. A molded article having more excellent gas barrier properties can be produced.

Further, when applied to the intermediate layer of a multilayer molded product, a molded product having excellent transparency can be obtained as compared with the case where the conventional recovered polyester is used alone. When such a polyester resin composition is used, the injection molding machine, the raw material drying and supply line up to the extruder input can be greatly simplified, and not only can the equipment cost be significantly reduced, but also long-term continuous molding can be performed. Even so, burns generated in the molded product can be significantly reduced.

Moreover, the obtained molded product is excellent in gas barrier properties, transparency and heat resistance, has a low amount of acetaldehyde, has a high strength of the bottle, and hardly causes delamination even when a knife is put in the bottle. .

[0117]

EXAMPLES Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples.

[0118]

Example 1 The dicarboxylic acid structural unit is composed of a terephthalic acid structural unit and an isophthalic acid structural unit, and the molar ratio of the terephthalic acid structural unit to the isophthalic acid structural unit (terephthalic acid / isophthalic acid) is 98/2, The diol structural unit is composed of ethylene glycol and has an intrinsic viscosity (IV)
Is 0.85 dl / g solid-phase polymerized polyethylene terephthalate (a): 50% by weight, and the dicarboxylic acid structural unit is composed of a terephthalic acid structural unit and an isophthalic acid structural unit, and the terephthalic acid structural unit and the isophthalic acid structural unit are Has a molar ratio (terephthalic acid / isophthalic acid) of 10/90, and comprises a diol structural unit of 1,3-bis (2-hydroxyethoxy) benzene structural unit and an ethylene glycol structural unit and a trimethylolpropane structural unit, When the total of the diol constituent units is 100 mol%, 1,3-
Bis (2-hydroxyethoxy) benzene constituent unit is 15 mol%, ethylene glycol constituent unit is 85 mol%, and trismethylo-
The lepropane structural unit is 0.3 mol%, and the IV is 0.1%.
85 dl / g of polyethylene isophthalate copolymer (b-1): After drying 50% by weight of each, melt-kneading is performed at a temperature of 275 ° C. using a twin screw extruder made by Ikegai and having a shaft diameter of 45 mm, and strands are discharged from a nozzle. It was extruded and cut into a shape to produce a cylindrical pellet having a diameter of 2.5 mm and a height of 3.5 mm.

During the melting and kneading, the cylinder 2 of the molding machine was used.
A vacuum line was installed at each location, and the pressure was reduced to a pressure of 30 mmHg to remove low molecular weight substances. The obtained polyester pellet was crystallized at 170 ° C. for 2 hours under a nitrogen stream to obtain a polyester (A-1) pellet. This polyester
The IV of (A-1) was 0.81 dl / g, the melting point was 248 ° C., and the density was 1,364 kg / m ³ .

Tables 1 and 2 show the properties of the prepared polyester and polyester pellets. Bottle flake (Repropolyethylene terephthalate, IV = 0.72 dl / g) manufactured by Wiz PET Bottle Recycle Co., Ltd. 95
% By weight and 5% by weight of the polyester (A-1) were dry-blended and vacuum-dried at 150 ° C. for 16 hours. Square plates having a thickness of 3 and 4 mm were molded using an injection molding machine (model name: M70B) at a molding temperature of 285 ° C. The molding cycle at this time was 70 seconds. The mold temperature was 10 ° C. The transparency of the obtained molded product,
Evaluation was made by measuring haze. Haze was measured with a haze meter. In addition, the thing with high haze has large haze and is inferior in transparency. As a result, 7 mm
% At 4 mm thickness.

Further, a 28 g preform was molded with an injection molding machine (machine name: M70B) using the same resin composition.
Molding temperature is 275 ° C and preform thickness is 4m
m, and the mold temperature was 10 ° C. The obtained preform is subjected to a PET bottle blow molding machine (Krupp Corpoplast L).
Using B01), a 500 ml carbonic acid bottle was formed. The preform stretching temperature at this time was 110 ° C.

A cut piece of this bottle was cut out, and the carbon dioxide gas permeability of the bottle was measured at 23 ° C. and a relative humidity of 60% using a gas permeability measuring device GPM-250 manufactured by GL Sciences Corporation.

Table 3 shows the obtained results.

[0124]

Example 2 In Example 1, the amount of bottle flakes was 90% by weight, and the amount of polyester (A-1) pellets was 10% by weight.
A molded product was prepared and evaluated under the same conditions as in Example 1 except that the above conditions were satisfied. The transparency (haze) of the obtained square plate
Was 5% at a thickness of 3 mm and 46% at a thickness of 4 mm.

Table 3 shows the results.

[0126]

Example 3 In Example 1, the amount of the bottle flake was 80% by weight, and the amount of the polyester (A-1) pellet was 20% by weight.
A molded product was prepared and evaluated under the same conditions as in Example 1 except that the above conditions were satisfied. The transparency (haze) of the obtained square plate
Was 4% at 3 mm thickness and 17% at 4 mm thickness.

Table 3 shows the results.

[0128]

[Comparative Example 1] In Example 1, no polyester (A-1) pellets were blended, and only bottle flakes were used.
A molded article was prepared under the same conditions as in Example 1 and evaluated. The transparency (haze) of the obtained square plate was 9% at 3 mm and 4 mm.
Was 79%.

Table 3 shows the results.

[0130]

Comparative Example 2 The dicarboxylic acid structural unit is composed of a terephthalic acid structural unit and an isophthalic acid structural unit, and the molar ratio of the terephthalic acid structural unit to the isophthalic acid structural unit (terephthalic acid / isophthalic acid) is 98/2, The diol structural unit is composed of ethylene glycol, and has an intrinsic viscosity (IV)
Is 0.85 dl / g solid-phase polymerized polyethylene terephthalate (a): 50% by weight, and the dicarboxylic acid structural unit is composed of a terephthalic acid structural unit and an isophthalic acid structural unit, and the terephthalic acid structural unit and the isophthalic acid structural unit are Is a molar ratio (terephthalic acid / isophthalic acid) of 30/70, is composed of an ethylene glycol structural unit (diol structural unit) and a trimethylolpropane structural unit, and when the ethylene glycol structural unit is 100 mol%, trismethylo is -0.3 mol% of the structural unit of lepropane
And 50% by weight of a polyethylene isophthalate copolymer (b-2) having an IV of 0.81 dl / g, dried at 275 ° C. using a twin-screw extruder having a shaft diameter of 45 mm manufactured by Ikegai. The mixture is melt-kneaded, extruded into a strand shape from a nozzle and cut, and is 2.5 mm in diameter and 3.5 m in height
m was prepared. During melting and kneading, vacuum lines were set up at two cylinder sections of the molding machine,
The pressure was reduced to mHg to remove low molecular weight substances. The obtained polyester pellet was crystallized at 170 ° C. for 2 hours under a nitrogen stream to obtain a polyester (A-2) pellet. The IV of this polyester (A-2) pellet is 0.8
1 dl / g, melting point: 252 ° C., density: 1369 kg / m
^{Was 3} . Tables 1 and 2 show the properties of the prepared polyesters and polyester pellets.

In Example 1, polyester (A-2) pellets were used instead of polyester (A-1) pellets, the amount of bottle flakes was 95% by weight, and polyester (A
A molded article was prepared with the amount of -2) being 5% by weight. The transparency (haze) of the formed square plate is 9% at 3 mm and 7 at 4 mm.
6%.

Table 3 shows the results.

[0133]

[Table 1]

[0134]

[Table 2]

[0135]

[Table 3]

As shown in Table 3, as in Examples 1 to 3, the polyester resin composition obtained by blending specific polyester pellets with repropolyester has a low haze (high transparency) and a high carbon dioxide gas permeability. , Resulting in a molded product with a low

[0137]

Example 4 The solid-phase polymerized polyethylene terephthalate was applied to the inner and outer layers by a 48-cavity lamination type injection molding machine manufactured by Husky.
(a) is 65% by weight, and the above-mentioned bottle flake and polyester (A-
1) A composition containing pellets and a 1: 1 weight ratio was preformed into 35. Preform weight is 2
The preform thickness was 8 mm, the preform thickness was 4 mm, and the mold temperature was 10 ° C. The obtained preform was bottle-molded with BROMAX 16 manufactured by Krupp Corpoplast. The bottle capacity was 500 ml and was in the shape for carbonated drinks.

The transmittance of carbon dioxide gas was measured using the section of the produced bottle. Table 4 shows the results.

[0139]

Comparative Example 3 A bottle was molded in the same manner as in Example 4, except that the solid-phase polymerized polyethylene terephthalate (a) was 70% by weight in the inner and outer layers, and the repropolyethylene terephthalate was 30% by weight in the intermediate layer. did.

Table 4 shows the results.

[0141]

[Table 4]

 ──────────────────────────────────────────────────続 き Continued from the front page F term (reference) 4F071 AA46 AA82 AA84 AA88 AG28 AH05 BB01 BB05 BB07 BB08 BC01 4J002 CF05W CF05X GG01 4J029 AA01 AA03 AB01 AD01 AD06 AD10 AE01 AE03 BA02 BA03 BA05 BA07 BB03A09 BA09 BF18 BF25 CA02 CA04 CA05 CA06 CB05A CB06A CB10A CC05A CC06A CF15 KA02 KJ02

Claims (6)

[Claims] 1. A dicarboxylic acid structural unit derived from a dicarboxylic acid containing [A] terephthalic acid and isophthalic acid;
Ethylene glycol and 1,3-bis (2-hydroxyethoxy)
A diol constituent unit derived from a diol containing benzene, and (i) a constituent unit derived from terephthalic acid is 15 to 99.5 mol% with respect to all dicarboxylic acid constituent units,
(Ii) the constitutional unit derived from ethylene glycol is 25 to 99.5 mol% with respect to all the diol constitutional units, and the structural unit derived from isophthalic acid is 0.5 to 85 mol%; The constituent unit derived from 3-bis (2-hydroxyethoxy) benzene is 0.5 to 75 mol%, the intrinsic viscosity is in the range of 0.5 to 1.5 dl / g, and the melting point is measured by a differential scanning calorimeter. (Tm (° C))
Satisfies the following general formula [I], [1 / 527-0.0017 · ln (1- (m _I + m _B ) / 200)] ^-1 -273 <Tm ≦ 265 ... [I] m _I is the ratio (mol%) of the constituent units derived from isophthalic acid in all dicarboxylic acid constituent units, and m _B is derived from 1,3-bis (2-hydroxyethoxy) benzene in all diol constituent units. The ratio (mol%) of the structural unit is shown.) A polyester pellet made of polyester having a density of 1350 kg / m ³ or more, and [B] polyethylene terephthalate (repropolyethylene terephthalate) passed through a molding machine at least once in a heated and molten state The polyester resin composition, wherein the polyester pellet [A] is in a range of 1 to 80% by weight and the repropolyethylene terephthalate [B] is in a range of 99 to 20% by weight. 2. The melting point (Tm (° C.)) of the following general formula [I ′]
The polyester resin composition according to claim 1, which satisfies the following. [1 / 527-0.0017 · ln (1- (m _I + m _B ) / 200)] ^-1 -270 <Tm ≦ 265… [I '] 3. A molded article comprising the composition according to claim 1. 4. The molded product according to claim 3, wherein the molded product is a preform, a bottle or a sheet. 5. A multilayer molded product comprising an inner layer, an intermediate layer, and an outer layer, wherein the inner layer and the outer layer are made of a resin containing polyethylene terephthalate resin as a main component, and the intermediate layer is made of a resin.
Wherein the intermediate layer is made of the polyester-based resin composition, and the thickness of the intermediate layer is in the range of 10 to 70% of the container thickness. Multi-layer molded products. 6. The multilayer molded product according to claim 5, wherein the molded product is a preform, a bottle or a sheet.