JPH05116207A - Refillable bottle and usage thereof - Google Patents

Abstract

PURPOSE:To obtain a refillable bottle made of plastic which is excellent in transparence and gas barrier properties and also lightweight, difficult to be broken, easy in handling and furthermore does not cause appearance failure and deterioration of mechanical strength even when the bottle is repeatedly sterilized and washed. CONSTITUTION:A refillable bottle is constituted of polyethylene naphthalate containing a constitutional unit derived from 2,6-naphthalene-dicarboxylic acid at the amount of >=50mol% when the constitutional unit derived from dicarboxylic acid is regulated to 100mol%. This refillable bottle shows haze of <=3% after operation for immersing the bottle in a 3% NaOH aqueous solution at 70 deg.C for 10 minutes is repeated 20 times.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refillable bottle, and more particularly, to a plastic bottle that can be refilled with juice, carbonated drink or the like after being collected for repeated use.

[0002]

BACKGROUND OF THE INVENTION In recent years, against the background of environmental problems, for example, cans filled with juice, carbonated drinks, seasonings, etc.
There is a social trend to effectively use resources by collecting and reusing containers such as bottles. When refilling the contents in the collection container for use, it must be sterilized and washed with, for example, hot alkaline water before refilling. Heretofore, almost only glass bottles have been used as containers that can be collected and reused in this manner, especially large bottles. However, since glass bottles are heavy and easily damaged, they are difficult to handle, and much labor is required for recovery and refilling.

By the way, in recent years, a polyethylene terephthalate bottle has been widely used as a large bottle replacing a glass bottle. This polyethylene terephthalate bottle has excellent transparency and gas barrier properties, is light, is not easily damaged, and is easy to handle.

However, even if the polyethylene terephthalate bottle is repeatedly collected and reused, the surface of the bottle is deteriorated due to the sterilization and cleaning as described above, resulting in a poor appearance and a decrease in strength, and the bottle cannot be reused. There was a problem that it did not exist.

For this reason, it is excellent in transparency and gas barrier property, is light and hard to be damaged, is easy to handle, and even if it is repeatedly sterilized and washed, it causes a poor appearance and a decrease in mechanical strength. The advent of a refillable plastic bottle that is free of charge is desired.

[0006]

SUMMARY OF THE INVENTION The present invention is intended to solve the problems associated with the prior art as described above, and is excellent in transparency and gas barrier property, is light, is not easily damaged, and is easy to handle. Further, it is an object of the present invention to provide a refillable plastic bottle that does not cause a poor appearance or a decrease in mechanical strength even after repeated sterilization and washing.

[0007]

SUMMARY OF THE INVENTION The refillable bottle according to the present invention has a constitutional unit derived from dicarboxylic acid as 100 mol% and a constitutional unit derived from 2,6-naphthalenedicarboxylic acid as 50 mol%. It is characterized in that it is made of polyethylene naphthalate contained in the above amount, and the total haze is 3% or less after the operation of immersing in a 3% NaOH aqueous solution at 70 ° C. for 10 minutes is repeated 20 times.

The refillable bottle according to the present invention preferably satisfies the following conditions. 70 ℃,
Washing for 10 minutes soaked in 3% NaOH aqueous solution for 20 minutes
In the bottle that was repeatedly used, (1) the tensile strength was 1
500 kg / cm ² or more, (2) Pressure resistance is 10 kg / cm
² or more, (3) Buckling strength is 50 kg / cm ² or more, (4) Carbon dioxide permeability coefficient is 4 [cc ・ mm / m ² D ・ atm]
Being below.

Further, in the method for repeatedly using a bottle according to the present invention, 100 constitutional units derived from dicarboxylic acid are used.
A bottle made of polyethylene naphthalate containing a structural unit derived from 2,6-naphthalenedicarboxylic acid in an amount of 50 mol% or more, when the mol% is set, is recovered,
After immersing at 70 ° C in a 3% NaOH aqueous solution for 10 minutes,
The feature is that the contents are filled again and repeatedly used.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The refillable bottle according to the present invention and the method of using the bottle will be specifically described below.

The bottle according to the present invention is made of polyethylene naphthalate. The polyethylene naphthalate used in the present invention may be a homopolymer or a copolymer, and hereinafter, both are included unless otherwise specified in the present specification.

The polyethylene naphthalate used in the present invention is derived from a dicarboxylic acid containing 2,6-naphthalenedicarboxylic acid and a hydroxy compound containing ethylene glycol. Containing the structural unit derived from 2,6-naphthalenedicarboxylic acid in an amount of 50 mol% or more, preferably 70 mol%, more preferably 80 mol% when the amount is 100 mol%. is doing.

In the polyethylene naphthalate used in the present invention, the constitutional unit derived from a dicarboxylic acid other than 2,6-naphthalenedicarboxylic acid may be contained in an amount of less than 50 mol%. Examples of the dicarboxylic acid other than the 6,6-naphthalenedicarboxylic acid include the following dicarboxylic acids.

Terephthalic acid, 2-methylterephthalic acid, isophthalic acid, 2,7-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, 4,
Aromatic dicarboxylic acids such as 4'-diphenyl ether dicarboxylic acid, 4,4'-diphenyl sulfone dicarboxylic acid, 4,4'-diphenoxyethane dicarboxylic acid, dibromoterephthalic acid, adipic acid, azelaic acid, sebacic acid, decandicarboxylic acid Acids such as aliphatic dicarboxylic acids, 1,4-cyclohexanedicarboxylic acid, cyclopropanedicarboxylic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, glycolic acid, p-hydroxybenzoic acid, p-hydroxyethoxybenzoic acid, etc. Examples thereof include hydroxycarboxylic acid.

Further, in the present invention, the hydroxy compound used for inducing polyethylene naphthalate contains ethylene glycol as a main component. Such a hydroxy compound may contain a hydroxy compound other than ethylene glycol as described below.

Propylene glycol, trimethylene glycol, diethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, decamethylene glycol, neopentylene glycol, p-xylene glycol, 1,4-cyclohexanedimethanol, bisphenol A, p , p-diphenoxysulfone, 1,4-bis (β-hydroxyethoxy) benzene,
2,2-bis (p-β-hydroxyethoxyphenol) propane, polyalkylene glycol, p-phenylene bis (dimethylsiloxane), glycerin and the like can be mentioned.

Further, trimesic acid, trimethylolethane, trimethylolpropane, trimethylolmethane,
A constitutional unit derived from a polyfunctional compound such as pentaerythritol may be contained in a small amount, for example, 2 mol% or less.

Further, a constitutional unit derived from a monofunctional compound such as benzoylbenzoic acid, diphenylsulfone monocarboxylic acid, stearic acid, methoxypolyethylene glycol or phenoxypolyethylene glycol is contained in a small amount, for example, 2 mol% or less. May be.

The polyethylene naphthalate used in the present invention can be obtained by polycondensing a dicarboxylic acid containing 2,6-naphthalenedicarboxylic acid and a hydroxy compound containing ethylene glycol. Specifically, such polycondensation is performed as follows, for example.

The polycondensation step comprises an esterification reaction step and a liquid phase polycondensation reaction step. Dicarboxylic acid and 1.02 to 1.4 mol, preferably 1.
A hydroxy compound slurry of dicarboxylic acid is formed from a mixture consisting of 03 to 1.3 moles of hydroxy compound. The slurry is continuously supplied to the esterification reaction step. The esterification reaction is carried out using a device in which at least two esterification reactors are connected in series, under the condition that the hydroxy compound is refluxed, while removing water produced by the reaction outside the system in a rectification column. .. The reaction conditions for carrying out the esterification reaction are such that the temperature of the first stage esterification reaction is usually 210 to 250 ° C, preferably 210 to 250 ° C.
And the pressure is usually 0.2 to 3 kg / cm ² G, preferably
0.5 to ² kg / cm ² G, and the temperature of the final stage esterification reaction is usually 220 to 260 ° C., preferably 240 to
The temperature is 260 ° C., and the pressure is usually 0 to 1.5 kg / cm ² G, preferably 0 to 1.3 kg / cm ² G. Therefore, when the esterification reaction is carried out in two stages, the esterification reaction conditions of the first stage and the second stage are within the above ranges, respectively, and when carried out in three or more stages, the second stage is carried out. The reaction conditions for the esterification reaction from the first stage to the stage immediately before the final stage are conditions between the reaction conditions of the first stage and the reaction conditions of the final stage. For example, when the esterification reaction is carried out in three steps, the temperature of the esterification reaction in the second step is usually 21
5 to 255 ° C., preferably 235 to 255 ° C., the pressure is usually 0 to ² kg / cm ² G, preferably 0.2 to 1.5 kg / cm ²
G. The reaction rate of these esterification reactions is not particularly limited in each stage, but it is preferable that the degree of increase in the esterification reaction rate in each stage is smoothly distributed. In the reaction product, it is usually desired to reach 90% or more, preferably 93% or more. A low-order condensate is obtained by these esterification steps, and the number-average molecular weight of the low-order condensate is usually 500 to 5,000.

The low-order condensate thus obtained is continuously supplied to the polycondensation reactor in the next liquid-phase polycondensation step. Regarding the reaction conditions for the polycondensation reaction, the reaction temperature for the first-stage polycondensation is usually 240 to 290 ° C, preferably 240 to 2
70 ° C. is more preferably 250 to 270 ° C., the pressure is usually 500 to 20 Torr, preferably 200 to 30 Torr, and the temperature of the final polycondensation reaction is usually 250 to
The temperature is 300 ° C, preferably 260 to 290 ° C, and the pressure is usually 10 to 0.1 Torr, preferably 5 to 0.5 Torr.

When the polycondensation reaction is carried out in two steps,
The polycondensation reaction conditions of the first stage and the second stage are within the above ranges, respectively.
The reaction conditions of the polycondensation reaction from the first stage to the stage before the final stage are the conditions between the reaction conditions of the first stage and the reaction conditions of the final stage. For example, when the polycondensation reaction is carried out in three stages, the reaction temperature of the second stage polycondensation reaction is usually 25.
0 to 290 ° C, preferably 250 to 280 ° C, more preferably 260 to 280 ° C, and the pressure is usually 50 to 2To.
rr It is preferably 40 to 5 Torr.

The intrinsic viscosity [η] reached in each of these polycondensation reaction steps is not particularly limited, but it is preferable that the degree of increase in the intrinsic viscosity at each stage is distributed smoothly.

In the polycondensation as described above, the esterification reaction can be carried out in the presence of the following basic compound. Examples of such a basic compound include tertiary amines such as trimethylamine, tri-n-butylamine and benzyldimethylamine, and quaternary ammonium such as tetraethylammonium hydroxide, tetra-n-butylammonium hydroxide and trimethylbenzylammonium hydroxide. , Lithium carbonate, sodium carbonate, potassium carbonate, sodium acetate and the like.

The method of adding these basic compounds is as follows:
It is not particularly limited, and may be added to all of the esterification reactors, or may be added to a specific reactor of the first stage or the second stage and thereafter.

When the basic compound as described above is used, the abundance of the dioxyethylene terephthalate component unit can be maintained at a relatively low level in the main chain forming the obtained polyethylene terephthalate.

The polycondensation reaction is preferably carried out in the presence of a catalyst and a stabilizer. As such a catalyst, germanium compounds such as germanium dioxide, germanium tetraethoxide and germanium tetra n-butoxide, antimony catalysts such as antimonium trioxide and titanium catalysts such as titanium tetrabutoxide can be used.

Of these catalysts, germanium dioxide compounds are preferably used. Examples of stabilizers include phosphoric acid esters such as trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, triphenyl phosphide, trisdodecyl phosphide, trisnonyl. Phosphites such as phenyl phosphides, acidic phosphoric acid esters such as methyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, dibutyl phosphate, monobutyl phosphate, dioctyl phosphate and phosphoric acid, phosphorus such as polyphosphoric acid A compound is used.

These catalysts and stabilizers may be used in the above-mentioned esterification reaction step or may be supplied to the first stage polycondensation reactor in the liquid phase polycondensation step.
In the polycondensation of polyethylene naphthalate as described above, the intrinsic viscosity [η] of the polyethylene naphthalate obtained from the final polycondensation reactor is usually 0.2 to 0.8.
dl / g, preferably 0.3 to 0.7 dl / g.

The above intrinsic viscosity [η] is determined as follows. Polyethylene naphthalate was dissolved in o-chlorophenol at a concentration of 1 g / 100 ml to prepare 25
The solution viscosity was measured with an Ubbelohde-type capillary viscometer at ℃, and then o-chlorophenol was gradually added to measure the solution viscosity on the low concentration side. η] is calculated.

The glass transition temperature is usually 80 to 130.
It is desirable that the temperature is ° C, preferably 100 to 120 ° C. In the present invention, the polyethylene naphthalate obtained as described above may be used after being pre-crystallized and / or further solid-phase polycondensed.

The polyethylene naphthalate used in the present invention is a heat-resistant stabilizer, a weather-resistant stabilizer, an antistatic agent, a lubricant, a release agent, an inorganic filler, a pigment dispersant, and a pigment as long as the object of the present invention is not impaired. Alternatively, it may contain various compounding agents such as dyes.

The bottle according to the present invention is formed from the above-mentioned polyethylene naphthalate, but together with polyethylene naphthalate, polyethylene terephthalate, polyethylene isophthalate, polyarylate, polybutylene are used together with polyethylene naphthalate within a range not impairing the object of the present invention. Polymers such as terephthalate, polycarbonate and 1,4-cyclohexylene dimethylene terephthalate may be contained.

The bottle according to the present invention is usually obtained by molding a preform from polyethylene naphthalate and subjecting this preform to stretch blow molding. The preform can be manufactured by molding by a conventionally known method, and is obtained by supplying the above-mentioned polyethylene naphthalate to a molding machine such as an injection molding machine or an extrusion molding machine and molding.

The bottle according to the present invention can be obtained by heating the above preform and stretch-blow molding according to a conventional method. The bottle according to the present invention has a stretching index defined as described below of 130 cm or more, preferably 140 to 230 cm, more preferably 150 to 220 c.
It is preferably stretched to m.

[0036]

[Equation 1] The stretching index of the bottle will be described below with reference to FIG.

In FIG. 1, the internal volume of the stretched bottle is the internal volume of the stretched bottle 1 excluding the spout 2, specifically, the internal volume of the bottle 1 below the support ring 8, Specifically, it means the inner volume of the bottle below the virtual straight line 9.

The internal volume of the unstretched preform is the internal volume of the preform 7 excluding the spigot 2, specifically, the internal volume of the preform 7 below the support ring 8, Specifically, it means the inner volume of the preform below the virtual straight line 9.

Furthermore, the inner surface area of the stretched bottle is 2
Is the inner surface area of the stretched bottle 1 excluding
It is the inner surface area of the stretched bottle below the support ring 8 of the bottle 1, and more specifically, the inner surface area of the bottle below the imaginary straight line 9.

The inner surface area of the stretched bottle (excluding the inner surface area of the plug portion) is divided into minute parts by detecting the surface shape with a coordinate measuring machine, and the minute surface area of the minute parts is integrated. It can be measured by the method. When the stretched bottle has a simple shape, the inner surface area can be obtained as an approximate value by assuming that the body of the bottle is a cylinder and the lower part and the upper part of the bottle are hemispheres.

Therefore, the stretching index of the stretched bottle as described above is determined by the inner surface area of the stretched bottle (excluding the inner surface area of the plug portion), the inner volume of the stretched bottle (excluding the volume of the plug portion) and the unstretched bottle. Internal volume (excluding spout volume)
Can be calculated. The internal volume of the bottle can be easily measured by adding a liquid such as water.

The bottle according to the present invention obtained as described above has excellent heat resistance and transparency, is light, is not easily broken, and is easy to handle. The bottle according to the present invention has
The operation of dipping in a 3% NaOH aqueous solution at 0 ° C. for 10 minutes was repeated 20 times, and the total haze was 3% or less, and the transparency was not lower than that of an unused bottle.

The total haze value was measured as follows. The center of the body of the bottle was cut, and the haze of the test piece was measured using a Nippon Denshoku Co., Ltd. haze meter NDH-20D in accordance with ASTM D 1003. The measurement was performed 3 times (n
= 3), and the average value was adopted.

The bottle according to the present invention can be repeatedly collected and refilled for use. It is preferable that such a bottle according to the present invention satisfies the following conditions.

After the above operation of immersing in a 3% NaOH aqueous solution at 70 ° C. for 10 minutes was repeated 20 times,
(1) Tensile strength is at 1500 Kg / cm ² or more, (2) a pressure resistance 10 Kg / cm ² or more, (3) buckling strength 50
Kg / cm ² or more, (4) Carbon dioxide permeability coefficient of 4 [cc ・
mm / m ² D · atm] or less.

The above measured values are measured as follows. (1) Tensile strength: A crosshead moving speed constant tensile tester was used to pull a Specimen punched from the center of the bottle body with an ASTM Type IV dumbbell at a speed of 10 mm / min.
The stress at the moment when the test piece broke was determined and used as the tensile strength (tensile strength at break (TS)).

The strength was measured in two directions, a vertical direction from the body and a direction perpendicular thereto, and the larger one was measured. (2) Compressive strength: Using a pipe hydraulic breakdown tester, the bottle was placed in a constant temperature water bath at 30 ° C, water pressure was applied at a water amount of 500 cc / min to measure the pressure at break, and this value was taken as the compressive strength.

The measurement was performed 3 times (n = 3) in each example, and the average value was adopted. (3) Buckling strength: Using a universal crosshead moving speed type universal testing machine, compress the bottle vertically with the crosshead speed of 10 mm / min and read the value at the moment when the load reaches the maximum value. Flexing strength.

The measurement was performed 3 times (n = 3) in each example, and the average value was adopted. (4) Carbon dioxide permeability coefficient was measured as follows.
Permat, a carbon dioxide permeation tester manufactured by Modern Control (USA)
Using a ran C-IV type, the carbon dioxide permeability coefficient of a sample consisting of a section at the center of the bottle body was measured by the Permatran method under the conditions of 23 ° C. and a relative humidity of 0%.

The bottle according to the present invention does not deteriorate in mechanical strength even after repeated washing as described above, has good gas barrier properties and heat resistance, and can be said to be suitable as a refill bottle.

In the method of repeatedly using a bottle according to the present invention, the bottle as described above is collected and then stored at 70 ° C. and 3% Na.
After soaking in the aqueous OH solution for 10 minutes, the contents are filled again.

In the present invention, the contents that can be filled in the bottle include drinking water, juice, carbonated drink, soy sauce, sauce,
Examples thereof include dressings, seasonings such as edible oil, liquors such as beer and wine, cosmetics, shampoos, detergents, and pharmaceuticals.

As described above, the number of times that the bottle can be collected and refilled is 20 times or more, preferably 7 times or more.

[0054]

The bottle according to the present invention is excellent in transparency and gas barrier property, is light and hard to be damaged, is easy to handle, and has a poor appearance even after repeated sterilization washing, and has a reduced mechanical strength. It can be refilled and used without any trouble.

The present invention will be described below with reference to examples.
The present invention is not limited to these examples.

[0056]

Example 1 A polyethylene naphthalate resin having the following physical properties, which was obtained from 2,6-dinaphthalenedicarboxylic acid and ethylene glycol, was molded with an injection molding machine M-100A manufactured by Meiki Seisakusho Co., Ltd. A preform for bottle formation was obtained. The molding temperature (set value) at this time was 270 to 290 ° C. The preform weight was about 65 g.

Polyethylene naphthalate resin: Intrinsic viscosity [η]: 0.6 dl / g Density: 1.356 g / cc Elevated temperature crystallization temperature (Tc): 220 ° C. Next, the preform obtained as described above CORPOP
It was molded with a LAST LB-01 molding machine to obtain a biaxially stretched bottle. At this time, the stretching temperature (preform surface temperature) is 13
It was 0 to 140 ° C.

The internal volume of the unstretched preform (excluding the plug portion) was 17 cm ² , and the internal volume of the obtained stretched bottle (excluding the plug portion) was 1484 cm ² . The inner surface area of the stretched bottle (excluding the inner surface area of the plug) is 678 cm.
^{Was 2} .

Therefore, the stretching index is calculated as follows. The bottle thus obtained was fully immersed in a 3% NaOH aqueous solution at 70 ° C. for 10 minutes, then taken out of the aqueous solution and cooled to room temperature.

This operation was performed once, and the immersion in the bottle was repeated up to 20 times under the same conditions. The physical properties of the bottle are as follows: before dipping test, after dipping 3 times, dipping 7 times, dipping 10 times,
All the items were measured after every 20 immersions.

The results are shown in Table 1.

[0062]

Example 2 2,6-Dinaphthalenedicarboxylic acid 80 mol%
A polyethylene naphthalate resin obtained from 20 mol% of terephthalic acid and ethylene glycol and having the following physical properties was bottle-molded in the same manner as in Example 1.

The stretching temperature at this time was 120 to 130 ° C. The bottle obtained here was immersed in the same manner as in Example 1 to measure the physical properties. The results are shown in Table 1.

Polyethylene naphthalate resin (2): Intrinsic viscosity [η]: 0.6 dl / g Density: 1.343 g / cc

[0065]

Comparative Example 1 A bottle of Kodapak ^™ brand 9921 manufactured by Eastman Kodak Company was molded in the same manner as in Example 1.
The stretching temperature at this time was 95 to 100 ° C.

Immersion was carried out in the same manner to evaluate the physical properties. The results are shown in Table 1.

[0067]

[Table 1]

[Brief description of drawings]

FIG. 1 is a sectional view of a bottle according to the present invention.

[Explanation of symbols]

 1 Bottle 2 Plug part 3 Upper shoulder part 4 Body part 5 Lower shoulder part 6 Bottom part 8 Support ring

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Claims (3)

[Claims] 1. A constitutional unit derived from a dicarboxylic acid is 1
It is made of polyethylene naphthalate containing a constitutional unit derived from 2,6-naphthalenedicarboxylic acid in an amount of 50 mol% or more when the amount is set to 00 mol%, and is immersed in a 3% NaOH aqueous solution at 70 ° C. for 10 minutes. A refillable bottle having a total haze of 3% or less after repeating the operation 20 times. 2. The refillable bottle according to claim 1, wherein the following conditions are satisfied after the operation of immersing in a 3% NaOH aqueous solution at 70 ° C. for 10 minutes is repeated 20 times: (a) tensile strength, and at 1500 Kg / cm ² or more, (b) compression strength is at 10 Kg / cm ² or more, or (c) buckling strength 50 Kg / cm ² or more, (d) carbon dioxide gas transmission The coefficient must be 4 [cc ・ mm / m ² D ・ atm] or less. 3. A constitutional unit derived from a dicarboxylic acid is 1
A bottle made of polyethylene naphthalate containing 50 mol% or more of a structural unit derived from 2,6-naphthalenedicarboxylic acid when the amount was set to 00 mol% was recovered, and the bottle was collected at 70 ° C. and 3% NaOH aqueous solution. A method for repeatedly using a bottle, which comprises immersing the bottle in the container for 10 minutes, filling the contents again, and repeatedly using the bottle.