JP4937466B2 - Polyester resin bottle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polyester resin for bottles excellent in transparency, heat resistance and mechanical performance, and a bottle obtained by molding the same.
[0002]
Saturated crystalline polyester resins such as polyethylene terephthalate (hereinafter sometimes referred to as PET) are excellent in mechanical strength, heat resistance, transparency, recyclability and gas barrier properties, and can be obtained by molding them. Bottles are widely used as materials for containers such as soft drinks, carbonated drinks, seasonings, detergents, and cosmetics.
[0003]
In order to manufacture a bottle from such a saturated crystalline polyester, generally, a saturated polyester is injection-molded to form a preform, and then the preform is loaded into a predetermined mold and stretch blow-molded to form a mouth. A bottle having a stopper and a body is obtained.
[0004]
Among the bottles obtained in this way, bottles used for beverages such as juices in particular are required to have heat resistance capable of withstanding the heat sterilization of the contents. ) To improve heat resistance.
[0005]
However, when a bottle manufactured using PET is heat sterilized, the heat resistant temperature of the bottle currently used is about 90 ° C. in consideration of productivity.
[0006]
In order to further improve the heat resistance, a method for improving the heat resistance by blending a resin having a high glass transition point (Tg) with PET was also examined. For example, a blend of polyethylene naphthalate (hereinafter sometimes referred to as PEN) and PET has been attempted. However, PET and PEN are inferior in compatibility, and simply blending them results in whitening of the resulting blend, and the resulting molded product is significantly inferior in transparency.
[0007]
Therefore, in JP-A-9-124785, transparency is enhanced by melt-kneading PET and PEN and transesterifying them. However, since the number of processes increases, it has become a problem in terms of productivity.
[0008]
For this reason, a polyester resin having high transparency and excellent heat resistance has been desired without going through heat treatment and melt-kneading processes.
[0009]
[Problems to be solved by the present invention]
An object of the present invention is to provide a polyester resin for bottles excellent in heat resistance, transparency and mechanical performance, and a bottle obtained by molding the same, in view of the above-mentioned problems of the prior art.
[0010]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that a polyester resin obtained by using a diol having a cyclic ether skeleton as a specific amount of a copolymer component has excellent heat resistance and transparency for bottles. As a result, the present invention has been found.
[0011]
That is, the present invention, diol 5 to 60 mol% having a cyclic ether skeleton represented by the following general formula (I) and / or (II), and ethylene glycol 30 to 95 mol% (provided that the diol component The diol component containing the cyclic ether skeleton represented by the general formulas (I) and (II) and the total amount of ethylene glycol is 90 mol% or more ), and 80 to 100 mol of terephthalic acid and / or its ester A bottle obtained by molding a polyester resin having the following properties (1) to (3) obtained by polycondensation with a dicarboxylic acid component containing 1%.
(1) The intrinsic viscosity (IV) measured at 25 ° C. using a mixed solvent having a weight ratio of phenol and 1,1,2,2-tetrachloroethane of 6: 4 is 0.4 to 1.5 (dl / g).
(2) The melt viscosity when measured at a measurement temperature of 240 ° C. and a shear rate of 100 (1 / s) is in the range of 700 to 5000 (Pa · s).
(3) The molecular weight distribution of the polyester resin is 2.5 to 12.0.
It is invention regarding.
[0012]
The polyester resin of the present invention comprises a diol containing 5 to 60 mol% of a diol having a cyclic ether skeleton, a diol component containing 30 to 95 mol% of ethylene glycol, and 80 to 100 mol% of an aromatic dicarboxylic acid and / or an ester thereof. It is a polyester resin obtained by polycondensation with a dicarboxylic acid component contained.
[0013]
In the present invention, 3,9-bis (1,1-dimethyl-2-hydroxyethyl) 2,4,8,10-tetraoxaspiro represented by the following structural formula (I) as a diol having a cyclic ether skeleton [5.5] Undecane (hereinafter sometimes referred to as SPG) and 5-methylol-5-ethyl-2- (1,1-dimethyl-2-hydroxyethyl) represented by the following structural formula (II) Examples include, but are not limited to, -1,3-dioxane (hereinafter sometimes referred to as DOG).
By using the above-mentioned diols, the polyester resin of the present invention can be characterized as having both higher heat resistance and mechanical performance.
[0014]
[Chemical 3]
[0015]
[Formula 4]
[0016]
In the present invention, diols represented by the structural formulas (I) and (II) and other diols other than ethylene glycol can be used within a range not exceeding 10 mol% of the diol component. These other diols are not particularly limited, but for example, trimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol Aliphatic diols such as polyethylene glycol, polypropylene glycol, polyalkylene glycols such as polybutylene glycol, trihydric or higher polyhydric alcohols such as glycerin, trimethylolpropane, pentaerythritol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,2-decahydronaphthalene diethanol, 1,3-decahydronaphthalene diethanol, 1,4-decahydronaphthalene diethanol, 1,5-deethanol Aliphatic diols such as hydronaphthalene diethanol, 1,6-decahydronaphthalene diethanol, 2,7-decahydro naphthalene diethanol, tetralin dimethanol, norbornane dimethanol, tricyclodecane dimethanol, pentacyclododecane dimethanol Bisphenols such as 4,4 ′-(1-methylethylidene) bisphenol, methylene bisphenol (bisphenol F), 4,4′-cyclohexylidene bisphenol (bisphenol Z), 4,4′-sulfonyl bisphenol (bisphenol S), etc. Alkylene oxide adducts, hydroquinone, resorcin, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenylbenzophenone and other aromatic dihydro Alkylene oxide adducts can be exemplified a sheet compound.
[0017]
Regarding the aromatic dicarboxylic acid and / or ester thereof used in the present invention, as the dicarboxylic acid component, terephthalic acid, isophthalic acid, phthalic acid, 2-methylterephthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, tetralindicarboxylic acid, etc. Examples of such esters include, but are not limited to, dimethyl ester, diethyl ester, diisopropyl ester, dibutyl ester, diisohexyl ester and the like.
Specific examples of the aromatic dicarboxylic acid ester include dimethyl terephthalate, diethyl terephthalate, didipropyl terephthalate, diisopropyl terephthalate, dibutyl terephthalate, and dicyclohexyl terephthalate.
In this invention, dicarboxylic acids other than aromatic dicarboxylic acid and / or its ester can be used as a dicarboxylic acid component in the range which does not exceed 20 mol% in all the dicarboxylic acid components. Other dicarboxylic acids that can be used include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecane dicarboxylic acid, cyclohexane dicarboxylic acid, decalin dicarboxylic acid, norbornane dicarboxylic acid, tricyclodecane Dicarboxylic acid, pentacyclododecanedicarboxylic acid, isophorone dicarboxylic acid, 3,9-bis (2-carboxyethyl) 2,4,8,10-tetraoxaspiro [5.5] undecane, tricarballylic acid and esterified products thereof However, the present invention is not limited to these examples.
[0019]
In the polyester resin of the present invention, the glass transition temperature of the polyester resin measured by a differential scanning calorimeter is 90 ° C. or higher, preferably 95 ° C. or higher, and the calorific value of the crystallization exothermic peak during cooling is 5 J / g or lower, preferably It is a polyester resin that is 0 J / g. By using a polyester resin having the above properties, a bottle having excellent heat resistance and transparency that is practically effective can be produced.
[0020]
There is no restriction | limiting in particular in the method of manufacturing the polyester resin of this invention, A conventionally well-known method is applicable. Examples thereof include a melt polymerization method such as a transesterification method and a direct esterification method, or a solution polymerization method. As the transesterification catalyst, esterification catalyst, etherification inhibitor, polymerization catalyst used in the polymerization, various stabilizers such as a heat stabilizer and a light stabilizer, polymerization regulators and the like, conventionally known ones can be used. Examples of the transesterification catalyst include compounds such as manganese, cobalt, zinc, titanium and calcium; examples of the esterification catalyst include compounds such as manganese, cobalt, zinc, titanium and calcium; and examples of the etherification inhibitor include amine compounds. .
[0021]
Examples of the polycondensation catalyst include compounds such as germanium, antimony, tin, and titanium. It is also effective to add various phosphorus compounds such as phosphoric acid, phosphorous acid, and phenylphosphonic acid as a heat stabilizer. In addition, a light stabilizer, an antistatic agent, a lubricant, an antioxidant, a release agent and the like may be added.
[0022]
In the esterification reaction, the addition time of SPG is not particularly limited, and may be added after the esterification reaction or the transesterification reaction. At that time, water may be added to improve the slurry property in the direct esterification method.
[0023]
In the present invention, various properties of the polyester resin are measured by the following methods.
(1) Intrinsic viscosity (IV)
The measurement was performed using a mixed solvent (mass ratio: phenol / 1,1,2,2-tetrachloroethane = 6/4) using an Ubbelohde viscometer at a constant temperature of 25 ° C.
(2) The melt viscosity measuring apparatus was manufactured by Toyo Seiki, model: Capillograph 1C, and measured at a measurement temperature of 240 ° C., a preheating time of 1 minute, a nozzle diameter of 1 mm, a nozzle length of 10 mm, and a shear rate of 100 (1 / s).
[0024]
(3) Molecular weight distribution (Mw / Mn)
Using a gel permeation chromatography (GPC) apparatus (model: Shodex-11) manufactured by Showa Denko KK, the solvent is 2 mmol% / L hexafluoroisopropanol containing sodium trifluoroacetate, and the sample concentration is about 0.05% by weight.
The detector used RI (Refractive Index Detector) and calibrated with a polymethyl methacrylate standard.
(4) The glass transition temperature and the glass transition temperature (Tg) of the crystallization exothermic peak polymer when the temperature is lowered are manufactured by Shimadzu Corporation, model: DSC / TA-50WS, and about 10 mg of a sample is sealed in an aluminum unsealed container. And was measured at a temperature elevation rate of 20 ° C./min in a stream of nitrogen gas (30 ml / min). At that time, the temperature at the midpoint of the region where the discontinuous portion appears in the base line (where the specific heat changed to half) was defined as Tg. The crystallization exothermic peak at the time of temperature decrease (hereinafter referred to as “ΔHc”) is obtained from the area of the exothermic peak that appears when the Tg is held at 280 ° C. for 1 minute after the measurement and then the temperature is decreased at a temperature decrease rate of 10 ° C./min. Value.
[0025]
The intrinsic viscosity of the polyester resin of the present invention is 0.4 to 1.5 (dl / g), preferably 0.5 to 1.0 (dl / g), more preferably 0.6 to 0.8 (dl). / G). The intrinsic viscosity is excellent when the intrinsic viscosity is 0.4 (dl / g) or more, and the moldability is excellent when the intrinsic viscosity is 1.5 (dl / g) or less.
[0026]
The melt viscosity of the polyester resin of the present invention is in the range of 700 to 5000 (Pa · s) when measured under the conditions of a measurement temperature of 240 (° C.) and a shear rate of 100 (1 / s).
In the case where the melt viscosity is as described above, the moldability is excellent.
[0027]
The molecular weight distribution of the polyester resin is preferably 2.5 to 12.0. In the case where the molecular weight distribution is as described above, the moldability is excellent. Here, the molecular weight distribution refers to the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn). The molecular weight distribution can be adjusted to 2.5 to 12.0 by selecting the composition ratio of SPG, the timing of its addition, the molecular weight, the polymerization temperature, and the additives.
[0028]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
[0029]
[Bottle molding and its evaluation]
Bottles were prepared using the resins shown in Tables 1 and 2 as raw materials, and subjected to a heat resistance test and a drop test. The test results are shown in Tables 1 and 2. The resin used in Comparative Example 1 in Table 2 is a product name: RT543 (IV: 0.75) manufactured by Nippon Unipet Co., Ltd.
(1) An injection molding machine (model: M200) manufactured by Meiko Seisakusho Co., Ltd. was used to mold a 30 g weight preform.
Next, using a blow molding machine (model: LB-01) manufactured by Krupp Corpoplast (Germany), a bottle having a capacity of 330 mL (pressure-resistant specification, petaloid bottom mold) was formed by blow molding.
The evaluation criteria for blow moldability are as follows.
Good: No problem Bad: Uneven thickness in the circumferential direction [0030]
(2) Drop test water The bottles filled with water were stored at 5 ° C. for 12 hours, and 15 samples were dropped freely (vertical drop) from the height of 1.5 m with the bottom of the bottle down.
The evaluation criteria are as follows.
Good: No change. Defect: There is a crack or leak.
(3) Hot water filling test Hot water of 85 ° C. (± 1 ° C.) was filled into a bottle and left for 12 hours, and the heat resistance was evaluated based on the holding ratio of height and volume. Evaluation was performed on five samples each. The evaluation criteria are as follows.
Height holding ratio: 99% or more was determined to be good, and less than 99% was determined to be defective.
Capacity retention: 98.5% or more was determined to be good, and less than 98.5% was determined to be defective.
[0031]
Examples 1-3, Comparative Examples 1-4
The raw material monomers listed in Tables 1 and 2 were heated to 200 ° C. in a predetermined amount and 0.03 mol of manganese acetate tetrahydrate per 100 mol of DMT (or the total amount of DMT and NDCM) in a nitrogen atmosphere. A transesterification reaction was performed.
After the distillation amount of methanol reaches 90% or more with respect to the theoretical amount, 0.01 mol of antimony (III) oxide and triphenyl phosphate (100 mol of DMT (or the total amount of DMT and NDCM) charged) TPP) 0.06 mol was added, the temperature was raised and the pressure was gradually reduced, and polymerization was finally performed at 280 ° C. and 0.1 kPa or less. The reaction was terminated when an appropriate melt viscosity was reached, and a polyester was obtained.
In Tables 1 and 2, DMT represents terephthalic acid dimethyl ester, NDCM represents 2,6-naphthalenedicarboxylic acid dimethyl ester, and EG represents ethylene glycol.
[0032]
【Effect of the invention】
The bottle polyester resin of the present invention is excellent in transparency and heat resistance, and a bottle obtained by molding it can be widely used in food container packaging materials and the like, and the industrial significance of the present invention is extremely large.
[0033]
[Table 1]
[0034]
[Table 2]

Claims (3)

5 to 60 mol% of a diol having a cyclic ether skeleton represented by the following general formula (I) and / or (II) , and 30 to 95 mol% of ethylene glycol (provided that the general formula (I) and A diol component containing a cyclic ether skeleton represented by (II) and a total amount of ethylene glycol of 90 mol% or more ) , a dicarboxylic acid component containing 80 to 100 mol% of terephthalic acid and / or an ester thereof, and A bottle obtained by molding a polyester resin having the following properties (1) to (3) obtained by polycondensation.
(1) The intrinsic viscosity (IV) measured at 25 ° C. using a mixed solvent having a weight ratio of phenol and 1,1,2,2-tetrachloroethane of 6: 4 is 0.4 to 1.5 (dl / g).
(2) The melt viscosity when measured at a measurement temperature of 240 ° C. and a shear rate of 100 (1 / s) is in the range of 700 to 5000 (Pa · s).
(3) The molecular weight distribution of the polyester resin is 2.5 to 12.0.
The bottle according to claim 1, wherein the dicarboxylic acid component is only terephthalic acid and / or an ester thereof.   The bottle according to claim 1 or 2, wherein the glass transition temperature of the polyester resin measured by a differential scanning calorimeter is 90 ° C or higher, and the calorific value of the crystallization exothermic peak during cooling is 5 J / g or less.