JPH0439501B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a polyester container with improved flavor retention, and more specifically, by reducing the acetaldehyde concentration in the container wall,
This invention relates to a polyester container with improved flavor retention for the contents. (Prior art) Containers made of polyethylene terephthalate made by biaxial stretch blow molding have excellent pressure resistance, rigidity, transparency, and impact resistance, and also have relatively low gas permeability to oxygen, carbon dioxide, etc., so they can be used for various purposes. It is widely used as a container for storing liquid foods, seasonings, cosmetics, etc., and plastic cans with a polyethylene terephthalate container body sealed with a metal lid are also on the verge of being put into practical use. . However, polyethylene terephthalate generates acetaldehyde due to thermal decomposition during thermoforming, and the acetaldehyde in the container wall transfers to the contents, resulting in the flavor of the contents.
The problem is that it damages the Conventional methods for reducing the acetaldehyde concentration due to thermal decomposition in polyethylene terephthalate include solid phase polymerization of polyethylene terephthalate after normal polymerization to reduce low molecular weight components or slightly increase the molecular weight, and molding during thermoforming. A method of lowering the temperature as much as possible and a method of reducing the shear (shear stress) during thermoforming as much as possible are being considered. (Problems to be Solved by the Invention) However, in manufacturing containers made of polyester such as polyethylene terephthalate, a substantially amorphous preform is formed by melting a general polyester and then injecting it into an injection mold. Since the preform is stretch-blown at a stretch molding temperature, increasing the molecular weight of polyester tends to reduce the injection moldability of polyester, and lowering the molding temperature reduces the load on the injection machine. This is not preferable because it makes the shear excessive, and lowering the shear tends to lower the molding speed and cause bubble entrainment, which is not preferable. Therefore, the present invention aims to provide a polyester container with improved flavor retention by reducing the acetaldehyde concentration contained in the polyester container wall without any particular adverse effect on the molding performance or physical properties of the polyester. Take it as a challenge. (Means for Solving the Problems) The present inventors added 5×10 ⁻⁷ to 3.0% by weight, especially 1% by weight, per thermoplastic polyester.
×10 ^-6 to 1.0% by weight, molecular weight 100 or more, especially 200
It has been found that by blending the above primary amino group-containing compound and using this resin composition for molding a container, the acetaldehyde concentration in the container wall can be significantly reduced. (Function) The mechanism by which acetaldehyde is produced by thermal decomposition of polyester is expressed by the following formula: Decomposition of polymer hydroxy end groups as shown in This is said to be due to the decomposition of the polymer main chain as shown in . The production of acetaldehyde due to this thermal decomposition is
Not only polyethylene terephthalate, but also other polyesters containing ethylene glycol as a diol component, such as gas barrier colloids containing terephthalic acid and isophthalic acid as dicarboxylic acid components, and ethylene glycol and bis(2-hydroxyethoxy)benzene as diol components. The same phenomenon is also observed in thermoplastic copolymerized polyesters such as polyester. In the present invention, when an amino group-containing compound of a certain molecular weight is blended into these thermoplastic polyesters,
This is based on the finding that a relatively small amount can significantly reduce the acetaldehyde concentration in thermoformed container walls. That is, the primary amino group-containing compound used in the present invention acts as an agent for reducing the concentration of acetaldehyde in polyester, and although its mechanism of action has not yet been fully elucidated, it can be expressed by the following formula: One of the reasons is thought to be that acetaldehyde is captured by the amino group of the amino group-containing compound through the reaction shown in . The primary amino group-containing compound used in the present invention is
Generally, it is important to have a molecular weight of 100 or more, particularly 200 or more. Primary amino group-containing compounds with molecular weights lower than this range are volatile or extractable, and although they have the ability to capture acetaldehyde, they impart a so-called amine odor to the contents, reducing flavor retention properties. There is a risk of deterioration. In the present invention, by blending the amino compound having the above molecular weight into the polyester in the above amount, acetaldehyde in the polyester can be effectively captured without giving off a so-called amine odor, and the flavor retention property of the polyester container can be improved. This can significantly improve the (Preferred Embodiment of the Invention) Polyester In the present invention, a polyester mainly composed of ethylene terephthalate units is generally used as the polyester. This is because this polyester has excellent stretch moldability and also has excellent properties such as mechanical properties and transparency. As a polyester mainly composed of ethylene terephthalate units, the acid component should be 80 mol% or more, especially 90 mol%
The above is the terephthalic acid component and the diol component.
Polyesters containing 80 mol% or more, particularly 90 mol% or more of ethylene glycol components are preferred.
Polyethylene terephthalate is most preferred, but modified copolyesters can also be used without losing the essence of polyethylene terephthalate, such as isophthalic acid, P-β-oxyethoxybenzoic acid, naphthalene 2,6-dicarboxylic acid. dicarboxylic acid components such as , diphenoxyethane-4,4'-dicarboxylic acid, 5-sodium sulfoisophthalic acid, adipic acid, sebacic acid or their alkyl ester derivatives, propylene glycol, 1,4-butanediol, neo Copolyesters containing glycol components such as bentyl glycol, 1,6-hexylene glycol, cyclohexanedimethanol, and ethylene oxide adducts of bisphenol A may also be used. Suitable examples of copolyesters used in the present invention include gas barrier copolyesters. This product (hereinafter sometimes referred to as BPR) has terephthalic acid component T and cisophthalic acid component I in the polymer chain, T:I = 95:5 to 5:95, especially 75:25 to 25. :75 molar ratio and ethylene glycol component E
and a bis(2-hydroxyethoxy)benzene component (BHEB) in a molar ratio of E:BHEB=99.999:0.001 to 2.0:98.0, particularly 99.95:0.05 to 40:60. As BHEB, 1,3
-bis(2-hydroxyethoxy)benzene is preferred. The T・I/E・BHEB copolyester (BPR) used in the present invention exhibits an oxygen permeability coefficient (PO ₂ ) on the order of about 1/3 to 1/4 that of polyethylene terephthalate, and the oxygen permeability coefficient For example, the above-mentioned
In the case of a multilayer container obtained by multilayer extrusion molding or multilayer injection molding of BPR and polyethylene terephthalate, thermoforming is more stable than with other gas barrier resins; It has the advantage that it has extremely good adhesion with polyethylene terephthalate and polyethylene terephthalate. Of course, the gas barrier polyester (BPR) used in the present invention may contain small amounts of other dibasic acid components or other diol components as long as their essential properties are not impaired. For example, P −β−
Oxycarboxylic acids such as oxyethoxybenzoic acid, naphthalene 2,6-dicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, 5-sodium sulfoisophthalic acid, adipic acid, sebacic acid, or alkyl ester derivatives thereof Dicarboxylic acid components such as propylene glycol,
It may contain glycol components such as 1,4-butanediol, neopentyl glycol, 1,6-hexylene glycol, cyclohexanedimethanol, and an ethylene oxide adduct of bisphenol A. The polyester used in the present invention should have at least a molecular weight sufficient to form a film, and is generally measured using a capillary viscometer in a mixed solvent of phenol and tetrachloroethane in a weight ratio of 60:40. 0.3 to 2.8, measured at temperature in °C
Intrinsic viscosity [η] of dl/g, especially 0.4 to 1.8 dl/g
It is desirable to have Among these, those with a relatively low molecular weight are used for injection molding, and those with a relatively high molecular weight are used for extrusion molding. Amino Group-Containing Compound The amino group-containing compound used in the present invention is preferably a compound containing a primary amino group in a concentration of 0.05 to 3000 milliequivalents, particularly 0.1 to 2000 milliequivalents, per 100 g of the compound. That is, if the concentration of the primary amino group is lower than the above range, the ability to capture acetaldehyde will be reduced, while if it is higher than the above range, the extractability will increase, which is not preferable. Furthermore, the primary amino group-containing compound used in the present invention must be stable at the thermoforming temperature of the polyester and must have some degree of miscibility in the polyester. This primary amino group-containing compound may be an aliphatic or aromatic low-molecular amino group-containing compound, or a high-molecular amino group-containing compound. In addition, this primary amino group-containing compound is
It may be a synthetic substance or a biological substance (natural substance). Suitable examples thereof include, but are not limited to: - Aromatic amines 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 2,2-bis(4-aminophenyl)propane.・Triazine compounds melamine, benzoguanamine, propioguanamine, stearoguanamine, spiroguanamine. - Aliphatic amines stearylamine, lauroylamine, eicosylamine, spiroacetal diamine, polyoxyethylene diamine. - Amino group-containing polymer Amino group-terminated polyethers, such as aminoethyl etherified or aminopropyletherified polyethylene glycol and/or polypropylene glycol; Amino group-terminated polyesters, such as aminoethyl etherified or aminopropyl etherified polyethylene adipate or sebacate; Amino group-terminated polyurethane; Amino group-terminated polyurea; Amino group-containing acrylic resin, such as 2-aminoethyl acrylate, 2-aminoethyl methacrylate, 3-aminoethyl acrylate, 3-aminoethyl methacrylate, N-
Copolymers of amino group-containing acrylates or methacrylates such as (2-aminoethyl)aminoethyl methacrylate and N-(2-aminoethyl)aminopropyl methacrylate with methyl methacrylate, ethyl acrylate, styrene, etc.; amino group-modified olefin resins; For example, polyethylene, polypropylene graft-modified with amino group-containing acrylate or methacrylate,
Ethylene-propylene copolymer; amino group-containing organopolysiloxane, for example, an organopolysiloxane containing a 3-aminoalkylsiloxane unit and units such as dimethylsiloxane, diphenylsiloxane, methylphenylsiloxane; primary amino group-containing melamine resin ; Guanamine resins containing primary amino groups; Alkyd resins containing primary amino groups, such as amino alcohol-modified alkyd resins.・Biological amines agmatine, alcaine, octopamine, D-octopine, cadaverine, cystamine, cysteamine, spermidine, spermine, tyramine, tryptamine, noradrenaline, histamine, bitiatin, hydroxytyramine, 5-hydroxytryptamine, pipotaurine, ・Amino acid azeserine, L- Asparagine, L-aspartic acid, L-α-aminobutyric acid, γ-aminobutyric acid, L-arginine, L-alloisoleucine, L-allotreonine, L-isoleucine, L-ethionine, L-ornithine, L-canavanine, L -Carboxymethylcysteine, L-kynurenine, glycine, L-glutamine, L-glutamic acid, creatine, L-cystathionine, L-cysteine, L-cysteic acid, L-cystine, L-citrulline, 3,4-dihydroxyphenylalanine , L-3,5-diiodotyrosine, L-serine, L-thyroxine, L-tyrosine, L-tryptophan, L-threonine, norvaline, norleucine, L-valine, L-histidine, L-hydroxyproline, L- Hydroxylysine, L-phenylalanine, L-α-phenylglycine, L-homoserine, L-methionine, L-1-methylhistidine, L-lanthionine, L-lysine, L-leucine, ・Peptide actinomycin C ₁ , apamin, eredoisin, oxytocin, gastrin, L-carnosine, L-glutathione (reduced type), L-glutathione (oxidized type), L-γ-glutamyl-L-cysteine, L-cysteinylglycine, vasopressin, α- Melanotropin, -Proteins Insulin, α-chymotrypsin, glucagon, crupein, corticotropin, subtilisin, secretin, cytochrome c, thyrocalcitonin, trypsin, papain, histones, ferredoxin, proinsulin, pepsin, hemoglobin, myoglobin, lactalbumin, lysozyme. The primary amino group-containing compound used in the present invention is
"Region of Chemistry" Volume 11, No. 10 (October 1957 issue)
The organic/(organic + inorganic) ratio calculated by the method described on pages 719 to 725 is 0.10 or more, especially
It is preferably 0.20 or more. The above organic and inorganic properties are calculated according to Table A below. This ratio is zero for inorganic compounds and 1 for straight chain aliphatic hydrocarbons.

【table】

[Table] Blend The blend of the present invention contains the above-mentioned polyester and a primary amino group-containing compound. , a lubricant, an ultraviolet absorber, an antioxidant, a nucleating agent, and the like can be blended in a known mixing ratio. The blend used in the present invention may contain one or more thermoplastic resins other than those mentioned above for the purpose of modification, such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-butene- 1 copolymers, ionomers (olefin resins such as ionically crosslinked olefin copolymers; polycarbonates; polyarylates, etc.). It is recommended that the blend be used in an amount of 100% or less.The blend may be prepared by dry blending pellets or powders of multiple resins to be blended, then melt-kneading and pelletizing. Since it is desirable to mix both of them evenly, it is advantageous to use a method in which multiple types of pellets or powders are mixed homogeneously using a Henschel mixer, etc., and then melt-kneaded. Advantageously, a method can be used in which a masterbatch is prepared by blending the polyester with an amino group-containing compound, melt-kneading the masterbatch, blending the masterbatch with the remaining polyester, and melt-kneading the same.Container and Molding Method Container according to the present invention is carried out by means known per se, except that the above-mentioned blend is used.
For example, sheets, pipes, or bottomed preforms for forming hollow containers are easily manufactured by extrusion molding, injection molding, compression molding, blow molding, or a combination thereof. When manufacturing these sheets, pipes, or bottomed preforms, it is preferable that at least the portion of the polyester to be stretch-molded be substantially amorphous. Of course, the parts that are not stretch-molded, such as the neck and bottom of the bottle, may be thermally crystallized. The method for forming the container is not particularly limited. For example, by stretch-molding a sheet, it is possible to obtain a cup-shaped container with a uniaxially oriented side wall or a plastic can body with a bottom, which is used by seaming with a metal lid. Also, by bottoming out the pipe,
A bottomed preform for stretch blow molding is obtained,
Furthermore, by stretching the pipe uniaxially or by stretch blow molding it biaxially, a plastic can body is obtained which can be wrapped with a metal lid at both ends. Furthermore, a biaxially oriented plastic bottle can be obtained by stretching the bottomed preform in the axial direction and expanding and stretching it in the circumferential direction. In order to improve the heat resistance of these stretch-molded containers, the orientation can be thermally fixed by heat treatment in a mold or the like under conditions of shape restriction. The blend of the present invention can also be applied to film containers. In this case, the blend is formed into a film by a T-die method or the like, and this film is stretched in the longitudinal direction at a stretching temperature, and then direction using a tenter or other means to obtain a biaxially stretched film, and this biaxially stretched film is used for manufacturing containers. In addition, this blend can also be used as a tray-shaped container for cooking food in a microwave oven and/or toaster oven, etc. For example, the blend can be formed into a tray shape and then thermally crystallized. Improves heat resistance. The polyester composition of the present invention can be used alone to manufacture containers as described above, but also in the form of a laminate with other materials, especially other thermoplastic resins. In particular, the composition (GFP) of the gas barrier polyester and primary amino group-containing compound of the present invention has excellent adhesion to polyethylene terephthalate (PET).
Used in the manufacture of containers in the form of a laminate with PET.
As a laminate, with the inside of the container on the left side, () asymmetric two-layer two-layer GFP/PET, PET/GFP, BL/PET, PET/BL, BL/GFP, GFP/BL, (symbol BL indicates GFP and PET. blends (e.g. scraps)) () Symmetric two-layer three-layer PET/GFP/PET, GFP/PET/GFP, () Asymmetric three-layer four-layer PET/BL/GFP/PET, GFP/BL/PET/GFP, PET /GFP/BL/PET, GFP/PET/BL/GFP, () Symmetrical three types and five layers PET/BL/GFP/BL/PET, GFP/BL/PET/BL/GFP, () Asymmetric three types and five layers PET/BL /PET/GFP/PET, GFP/BL/GFP/PET/GFP, PET/GFP/PET/BL/PET, GFP/PET/GFP/BL/GFP, () Symmetrical three-layer seven-layer PET/BL/PET/GFP /PET/BL/
PET, GFP/BL/GFP/PET/GFP/BL/
An example of this is GFP. As polyethylene terephthalate (PET), in addition to using polyethylene terephthalate alone, it is also possible to use a composition in which a primary amino group-containing compound is similarly blended with polyethylene terephthalate for the purpose of reducing the acetaldehyde concentration. be. In this stack, GFP:
The thickness ratio of PET is 5:1 to 1:20, especially 2:1
It can be varied within the range of 1:10 to 1:10,
The thickness of the GFP layer is preferably in the range of 20 to 1500 μm, particularly 30 to 1000 μm, depending on the shape and internal volume of the container, or the wall thickness of the container. The above-mentioned laminate can be manufactured by co-extrusion using extruders and multi-layer dies, the number of which corresponds to the type of resin layer, or by co-extrusion, which uses a number of extruders and multi-layer dies corresponding to the type of resin layer. It can also be carried out by co-injection using a co-injection runner and an injection mold. The molding into a container is the same as for a single layer. The blends of the invention may also be used with other materials such as aluminum foil, steel foil, iron foil, tin foil,
Containers can be made in the form of a laminate with metal foil such as TFS foil, gas barrier resin other than the above-mentioned BPR, such as ethylene-vinyl alcohol copolymer with an ethylene content of 20 to 70 mol%, xylylene group-containing polyamide resin, etc. Can be used for manufacturing. In particular, when the former ethylene/vinyl alcohol copolymer and the blend of the present invention are used in coextrusion molding or co-injection molding, acetaldehyde generated by thermal decomposition of the ethylene/vinyl alcohol copolymer is also contained in the blend. has the advantage of being captured by primary amino group-containing compounds. (Application) The polyester container of the present invention is a container for storing contents whose flavor is substantially impaired due to the presence of acetaldehyde, by containing a small amount of a primary amino group-containing compound as an acetaldehyde concentration lowering agent. As such, it is useful for retaining their flavor. Therefore, for example, oil and fat foods such as tempura oil and salad oil; seasonings such as mayonnaise, dressing, and ketchup; various syrups such as ice syrup;
Confectionery such as water yokan and jelly; Alcoholic beverages such as shochu; Various carbonated drinks including cola, cider, plain soda, etc.; Straight drinks such as lemon juice, orange juice, plum juice, grape juice, and strawberry juice.
Fruit juice drinks such as juice or fruit juice drinks containing nectar or agar; Retractable drinks such as coffee and tea; Health-oriented drinks such as vitamin-fortified drinks, aloe drinks, herbal drinks, health vinegar drinks, and isotonic drinks; Green tea,
Sugar-free beverages such as kombucha, oolong tea, amachiyazuru tea, barley tea, matte tea, persimmon leaf tea, ginseng tea, corn potage, consommé soup, shellfish extract drink, mineral water; lactic acid bacteria beverages; fermentation Useful as a container for storing milk drinks, etc. (Example) The present invention will be explained more specifically using the following example.
In addition, each measurement in each Example was performed according to the following method. () Thermoplastic polyester (PET or
Intrinsic viscosity (IV) of BPR) An Ubbelohde viscometer was used. Measurement was performed at 30°C using a mixed solvent of phenol/tetrachloroethane = 6/4 (weight ratio). () Molecular weight of amino group-containing compound The molecular weight of the amino group-containing compound was calculated from the atomic weight of the contained elements and the number of each element from the chemical formula of the corresponding compound. () Determination of primary amino group concentration in amino group-containing compounds The determination of primary amino groups was performed by potentiometric titration. That is, about 1 g of each sample of the primary amino group-containing compound used was strained, and m-cresol (10 mmHg, 95 ~
96°C distillation) was added and dissolved in a vacuum desiccator for 24 hours. Next, a special grade perchlorine reagent (60% ethyl alcohol solution) was added to a mixed solution of purified isopropyl alcohol and propylene glycol in a volume ratio of 2:1 as a potential adjusting agent to adjust the concentration to 0.005N. This was used as a titration reagent. Quantification of primary amino groups was determined from the inflection point obtained from a plot of the apparent potential and perchloric acid consumption. Potentiometric titration was performed using a HM-5 PH meter manufactured by Toa Denpa Kogyo Co., Ltd. () Amount of acetaldehyde in the material (AA) The amount of acetaldehyde in the material was determined using the Celanese method. That is, about 1 g each of the body and mouth of the sample described in each example was simultaneously ground in liquid nitrogen, and 30 to 40 mg of the sample was ground at the same time in liquid nitrogen.
After filling a pre-prepared glass insert, it was introduced directly into the injection section of a gas chromatograph (Shimadzu GC-6A model) and heated at 145°C for 20 minutes to volatilize the acetaldehyde in the material. After that, the temperature of the column (Polapack Q, 3φX2m) was lowered from room temperature.
The temperature was raised to 140°C and acetaldehyde analysis was performed. After the measurement, the weight of (sample + glass insert) was carefully determined, and the weight of the test sample was calculated from the difference from the weight of the glass insert. Results are average values of three repeated measurements. () Container transparency (haze, HZ) Transparency (haze) was measured using a direct reading haze meter manufactured by Toyo Seiki Seisakusho, and the haze value (HZ) at the center of the body of each sample was measured. It was measured. The results show the average of five measurements for each sample. Example 1 For 100 parts by weight of polyethylene terephthalate (PET-A) with an intrinsic viscosity (IV) of 0.75 dl/g, as a primary amino group-containing compound, a compound with a molecular weight of
8000, 1.0 part by weight of polyoxyethylene diamine (POEDA) with an amino group concentration of 25.0 meq/100g, and an organic/(organic + inorganic) ratio of 0.66 (hereinafter sometimes referred to as PHR). Add
10 at room temperature using a tumbler type dry blender
Dry blended for a minute. The obtained dry blend was transferred to Nissei Resin Kogyo Co., Ltd.
FS-170N injection molding machine, the weight is 37
g, wall thickness is 2.6mm. A preform was molded. In addition, the injection conditions at this time are: Barrel temperature setting: (rear) 250°C, (middle) 265°C, (front) 271°C, (nozzle) 272°C, Screw rotation speed: 70 rpm. Injection pressure Force: 46Kg/ ^cm2 . Cooling water temperature: 11℃. Molding cycle: 36 seconds. For comparison, a preform of PET-A alone (weight: 37 g, wall thickness: 2.6 mm) was also molded using the injection molding machine and injection conditions described above. The PET-A single preform obtained in this way and polyoxyethylene diamine were
2 of blend preforms with 1.0PHR added
The type was molded using an OBM-1G type biaxial stretch blow molding machine manufactured by Toyo Foods Machinery Co., Ltd. The total volume was approximately 1035ml.
(Weight: 37 g) A cylindrical bottle was molded. The bottle molding conditions are a preform temperature of 100
After heating at ℃ for 30 seconds, blow molding was performed in a mold for 4 seconds. Regarding the two types of biaxially stretched blow bottles obtained, the amount of acetaldehyde (AA) in each bottle material was measured by the method described in () above. AA in the PET-A single bottle material was 5.9 ppm, while AA in the blend bottle material to which 1.0 PHR of polyoxyethylene diamine (POEDA) was added was 0.2 ppm. It is known that by adding 1.0 PHR of POEDA, the residual rate of AA in the material is reduced to approximately 3%. Next, regarding these two types of biaxially stretched blow bottles, the transparency (haze, HZ) of the center portion of each bottle was measured according to the method described in () above. While the HZ of the PET-A carrier bottle was 1.7%, the HZ of the blend bottle was also 1.7%.
%, and virtually no significant difference was observed in terms of transparency. Example 2 For 10 kg of polyethylene terephthalate (PET-B) with an intrinsic viscosity (IV) of 0.65 dl/g,
As a primary amino group-containing compound, spiroacetal diamine (SADA,
Molecular weight is 274.4 Amino group concentration is 729 meq/100
g and the organic/(organic + inorganic) ratio is 0.50)
After adding 10g of powder and mixing it homogeneously using a Henschel mixer, use a pelletizer (setting temperature of each part of the cylinder: 265℃, screw rotation speed:
PET-B/
Obtained SADA masterbatch (pellets). The master batch obtained in this way,
PET-B chips (pellets) were used in the tumbler type dry blender described in Example 1 to obtain the following three types of dry blends: Masterbatch: PET-B = 1:200 =
0.0005PHR, Master batch: PET-B=1:100=
0.001PHR, Master batch: PET-B=1:10=
0.01PHR. A total of 4 types of materials, including the 3 types of dry blends obtained in this way and PET-B alone, were
Using the injection molding machine and biaxial stretch blow molding machine described in Example 1, under the same injection and blow molding conditions as in Example 1, a cylindrical mold with a full filling volume of about 1035 ml (weight 37 g) was produced. The bottle was molded. Regarding the four types of biaxially stretched blow bottles obtained, the amount of acetaldehyde (AA) in each bottle material was measured according to the method () described above. The results are shown in Table 1. Table 1 shows that even when the amount of spiroacetal diamine (SADA) added is in such a low concentration range, AA in the material is reduced to about 25% or less, and the effect of reducing acetaldehyde is large. Next, the transparency (haze, HZ) of the center portion of the body of each of the four types of biaxially stretched blow bottles was measured according to the method described in () above. The results are also shown in Table 1. It is known from Table 1 that within such a range of addition amounts of spiroacetal diamine, there is no substantially significant difference in transparency.

[Table] Example 3 Using an ASB-250TH co-injection/biaxial stretch blow molding machine manufactured by Nissei ASB Machinery Co., Ltd., polyethylene terephthalate (PET- A) For 100 parts by weight, as an amino group-containing compound, add 0.5 spiroguanamine (SGA) with a molecular weight of 434.2, an amino group concentration of 921 meq/100g, and an organic/(organic + inorganic) ratio of 0.28. The dry blend containing the added parts by weight is supplied, and the terephthalic acid component and isophthalic acid component are added to the polymer chain at a ratio of 70:30 to the sub-injection machine of the same machine.
It contains an ethylene glycol component and a bis(2-hydroxyethoxy)benzene component in a molar ratio of 95:5, and has an intrinsic viscosity (IV) of
Thermoplastic polyester (BPR) with 0.69 dl/g
A dry blend (referred to as GFP) in which 0.5 part by weight of the above-mentioned spiroguanamine (SGA) was added to 100 parts by weight was supplied, respectively. And, Main injection machine setting temperature: Rear part; 280℃, middle part;
280℃, nozzle part; 285℃. Sub-injection machine setting temperature: Rear; 195℃, middle part;
215℃, nozzle part; 215℃. Hot runner nozzle temperature setting: 285°C Primary injection pressure (gauge pressure) of the dry blend of PET and SGA: 125Kg/cm ² . Injection pressure (gauge pressure) of the GFP: 150Kg/cm ² Secondary injection pressure (gauge pressure) of the dry blend of PET and SGA: 95Kg/cm ² . Under co-injection conditions, the weight is 59 g, the total thickness is 4.1 mm, inner layer (blend of PET and SGA): middle layer (GFP):
The thickness ratio of the outer layer (blend of PET and SGA) is
A multilayer preform with a ratio of 0.5:1:1.5 was molded, and then in a blow zone, the multilayer preform was heated at a temperature of 100°C.
Under the conditions, the longitudinal (axial) direction stretching ratio is 2.5 times,
Biaxial stretching blowing is performed with a lateral (circumferential) stretching ratio of 3.5 times, the weight is 59g, and the full volume is 1520ml.
A cylindrical multilayer bottle was molded. Further, using only the main injection machine of the co-injection/biaxial stretch blow molding machine, a bottle of the same shape and made of the polyethylene terephthalate (PET-A) alone was molded under the same conditions. Regarding the two types of biaxially stretched blow bottles obtained, the amount of acetaldehyde (AA) in the material of each bottle was measured by the method described in () above. While the amount of acetaldehyde (AA) in the material of the PET-A single bottle was 8.6 ppm,
The AA of the multilayer bottle in which 0.5 parts by weight of the spiroguanamine (SGA) was added to all layers was 0.4 ppm.
It is known that by adding 0.5 parts by weight of SGA, the residual rate of AA in the material can be reduced to about 5%. Next, for these two types of single-layer and multi-layer bottles, the transparency (haze, HZ) of the center portion of each bottle was measured according to the method described in () above. The HZ of the PET-A single-layer bottle was 1.9%, whereas the HZ of the multi-layer bottle was 1.6%, and no significant difference was observed in terms of transparency. Further, according to the method described in Japanese Patent Application No. 62-98596, under the following conditions: (1) the temperature is 30°C and the humidity is 20% RH; (2) the temperature is 30°C and the humidity is 80% RH; Said PET
-A single layer bottle and the multilayer bottle,
An oxygen gas permeability test was conducted. Under the conditions (1), the PET-A single layer bottle is
7.12, the multilayer bottle has an oxygen gas permeability of 2.60, and when measured under the conditions of (2), the PET-A single-layer bottle has an oxygen gas permeability of 7.20 and the multilayer bottle has an oxygen gas permeability of 2.63 (unit: cc/ ^m2 . day・atm), and the effect of improving gas barrier properties due to the presence of the BPR as an intermediate layer was clearly demonstrated. Example 4 (A) Single bottle of polyethylene terephthalate (PET-A) described in Example 3 (control. Weight: 59 g, full volume: 1520 ml), (B) PET-A100 weight described in Example 1 Bottle containing 1.0 part by weight of polyoxyethylene diamine per part (weight: 37 g, full volume:
(1035 ml), (C) A bottle containing 0.01 part by weight (PHR) of spiroacetal diamine added to 100 parts by weight of PET-B described in Example 2 (weight: 37 g, full volume 1035 ml), and (D) Implementation 100 each of PET-A and BPR described in Example 3
Four types of multilayer bottles (weight: 59 g, full volume: 1520 ml) each containing 0.5 parts by weight of spiroguanamine are filled with commercially available 1400 g square cans of salad oil. 37 after sealing the mouth.
It was stored in a constant temperature room (dark place) at ℃ for 7 days. Thereafter, about 200 ml of the salad oil was transferred to a 300 ml beaker and kept at about 60°C on a hot plate. On the other hand, about 200 ml of the salad oil in the square can immediately after opening was transferred to a 300 ml beaker, and kept at about 60°C on a hot plate in the same manner as before. Then, for the 21 panel members, the above (A) salad oil filled in the bottle and the above
(B) Salad oil filled in a bottle. (A) the salad oil filled in the bottle;
(C) Salad oil filled in a bottle. (A) the salad oil filled in the bottle;
(D) Salad oil filled in a bottle. Nodotora was asked to judge whether the flavor was similar to that of salad oil in a rectangular can that had just been opened. In the flavor test, 20 out of 21 people said,
One person answered that the flavor of the salad oil filled in the bottle (B) was closer to the salad oil in the square can, and one person answered that the flavor of the salad oil filled in the bottles (A) and (B) was closer to that of the salad oil in the square can. I answered that I didn't know if it was similar to the one in a square can. In the next test, 16 out of 21 people said that the salad oil filled in the bottle (C) was better, and 2 people said that the salad oil filled in the bottle (A) was better than the salad oil in the square can. Each said the flavors were similar. Three people answered that they did not know. Furthermore, in the test, 18 out of 21 people answered that the flavor of the salad oil filled in the bottle (D) was closer to the salad oil in the square can, and 3 people answered that they did not know. From these results, it is clear that when a small amount of a specific primary amino group-containing compound is added to a thermoplastic polyester, the flavor retention of the contents stored in the polyester container can be significantly improved.

Claims (1)

[Scope of Claims] 1. A resin composition comprising a thermoplastic polyester blended with a primary amino group-containing compound having a molecular weight of 100 or more, excluding polyamide, in an amount of 5 x 10 ^-7 to 3.0% by weight based on the polyester. A polyester container with improved flavor retention. 2 The amino group-containing compound has a molecular weight of 100 or more, and the primary amino group is 0.05 to 3000 milliequivalents/
The polyester container according to claim 1, wherein the polyester container contains the compound at a concentration of 100 g.