JPH0584808A - Saturated polyester bottle - Google Patents

Abstract

PURPOSE:To realize a bottle, which is excellent in resistance to stress-cracking and at the bottom of which no crack develops due to external factors such as temperature, moisture, drug, solvent, line lubricant and the like. CONSTITUTION:In the saturated polyester bottle 1 concerned consisting of a mouth part 2, an upper shoulder part 3, a cylindrical part 4 and a self-supporting bottom part 5, at least the bottom part of the bottle is made of saturated polyester, which contains 0.1-0.6mol. part of multi-functional compound component unit to 100mol. part of dicarboxylic acid compound component unit and has intrinsic viscosity [eta[ of 0.5-1.0dl/g.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a saturated polyester bottle, and more particularly to a saturated polyester self-standing bottle having excellent stress crack resistance.

[0002]

BACKGROUND OF THE INVENTION In recent years, various plastic materials have been used as materials for soft drink bottles such as juice and carbonated drink bottles such as cola. Among these plastic materials, saturated polyester such as polyethylene terephthalate is It is widely used because of its excellent transparency, gas barrier property, heat resistance and mechanical strength.

As the shape of the saturated polyester bottle, a self-standing bottle represented by a bottle having a petaloid shape as shown in FIG. 1 (petaloid bottle), and a bottle bottom having a substantially hemispherical shape as shown in FIG. Generally, bottles (round bottom bottles) and the like that have a shape are generally used. In the case of the self-supporting bottle, a larger stress is applied to the bottom portion than in the case of the round bottom bottle, so that the bottom portion may be cracked in the distribution stage from liquid filling to sales. On the other hand, round-bottom bottles require a member (hakama) to be attached to the bottom of the bottle to protect the center of the bottom surface, which is inferior in mechanical strength, and at the same time, have many bottle manufacturing processes. There is a problem of becoming.

The cause of cracks at the bottom of a self-standing bottle such as a petaloid bottle is considered as follows. Since the self-standing bottle has a more complicated bottom shape than a round-bottom bottle and can be stretched in many portions, residual stress during molding tends to remain around the boundary between the stretched portion and the unstretched portion.
Therefore, at the bottom of the bottle, the strength of the material is reduced mainly due to the influence from the outside, and cracks are generated due to the residual stress. As external factors for the occurrence of cracks at the bottom of the bottle, temperature, moisture, chemicals, solvent, line lubricant, etc. are considered.

Conventionally, in a self-standing bottle such as a petaloid bottle, a saturated polyester having a large molecular weight is used to increase the strength of the bottom portion and prevent the occurrence of cracks. However, saturated polyester with a large molecular weight
There are problems that the moldability is poor and the cost of the resin is high.

The inventors of the present invention have made extensive studies based on the above findings, and as long as the saturated polyester contains a certain amount of a polyfunctional compound and the intrinsic viscosity [η] is within a certain range, the petaloid is obtained. The present invention has been completed by discovering that the occurrence of cracks at the bottom of a self-standing bottle such as a bottle can be almost completely prevented, and that the transparency and gas barrier properties of the bottle are not impaired.

[0007]

It is an object of the present invention to provide a saturated polyester having excellent stress crack resistance and having self-sustaining property such that cracks do not occur at the bottom due to external factors such as temperature, moisture, chemicals, solvents and line lubricants. Intended to provide bottles made.

[0008]

SUMMARY OF THE INVENTION The bottle according to the present invention is a saturated polyester bottle comprising a spout part, an upper shoulder part, a body part and a self-supporting bottom part, and at least the bottom part of the bottle contains 100 parts of a dicarboxylic acid compound component unit. A saturated polyester containing 0.1 to 0.6 parts by mole of a polyfunctional compound component unit and having an intrinsic viscosity [η] in the range of 0.5 to 1.0 dl / g. Is characterized by.

In the present invention, trimethylolpropane is preferably used as the polyfunctional compound. The saturated polyester bottle according to the present invention is excellent in stress crack resistance even if the bottom portion has a petaloid shape.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The saturated polyester bottle according to the present invention will be described below. Examples of the saturated polyester used as the material of the bottle according to the present invention include terephthalic acid or its ester-forming derivative (for example, lower alkyl ester, phenyl ester, etc.) and ethylene glycol or its ester-forming derivative (for example, monocarboxylic acid ester ethylene). A saturated polyester obtained from a polyfunctional compound and an oxide) is used.

The saturated polyester used in the present invention is
It contains a certain amount of polyfunctional compounds. Examples of such polyfunctional compounds include trimethylolmethane, trimethylolethane, trimethylolpropane, pentaerythritol, and the like, with trimethylolpropane being particularly preferred. The polyfunctional compound component unit is usually 0.1-0.6 mol part, preferably 0.2-0.4 mol part, when the dicarboxylic acid compound component unit constituting the saturated polyester is 100 mol part. Included in the range amount. If the content of the polyfunctional compound component unit is too small, the molded bottle is inferior in stress crack resistance, and if the content is too large, gelation occurs, resulting in poor appearance and molding failure when molded into a bottle. ..

Such saturated polyester contains 20 other dicarboxylic acid compounds other than terephthalic acid and ethylene glycol and / or other dihydroxy compounds.
It may be copolymerized in an amount of not more than mol%.

Specific examples of the dicarboxylic acid compound used for copolymerization other than terephthalic acid include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid and diphenoxyethanedicarboxylic acid; adipic acid. , Sebacic acid,
Aliphatic dicarboxylic acids such as azelaic acid and decanedicarboxylic acid; and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid.

As dihydroxy compounds used for copolymerization other than ethylene glycol, specifically, aliphatic glycols such as trimethylene glycol, propylene glycol, tetramethylene glycol, neopentyl glycol, hexamethylene glycol and dodecamethylene glycol; cyclohexane Alicyclic glycols such as dimethanol; bisphenols; hydroquinone,
Examples thereof include aromatic diols such as 2,2-bis (4-β-hydroxyethoxyphenyl) propane.

Such a saturated polyester forms a polyester either by the ethylene terephthalate component unit alone or by randomly arranging the ethylene terephthalate component unit and the dioxyethylene terephthalate component unit to form an ester bond.

The intrinsic viscosity [η] of such a saturated polyester measured at 25 ° C. in o-chlorophenol was 0.1.
The range is 5 to 1.0 dl / g, preferably 0.6 to 0.9 dl / g, and more preferably 0.6 to 0.8 dl / g. When the intrinsic viscosity [η] is in the above range, the melt moldability and mechanical strength are excellent.

The melting point is usually 210 ° C. to 265 ° C.,
It is preferably 220 to 260 ° C, and the glass transition temperature is usually 50 to 120 ° C, preferably 60.
It is desirable that the temperature is -100 ° C.

The saturated polyester used in the present invention includes various compounding agents such as heat resistance stabilizers, weather resistance stabilizers, antistatic agents, lubricants, mold release agents, inorganic fillers, pigment dispersants, pigments and dyes. Can be added within a range that does not impair the object of the present invention.

The saturated polyester bottle according to the present invention comprises the saturated polyester as described above,
It is a self-supporting bottle comprising an upper shoulder part, a body part and a bottom part having self-supporting property. The bottom of such a self-supporting bottle has, for example, a petaloid shape as shown in FIG. In addition, the wall thickness at the shoulder of the bottle (15 mm below the support ring along the surface of the bottle) is usually 0.3 to 0.
The thickness of the body is 5 mm, and the thickness of the body is usually about 0.25 to 0.35 mm.

The saturated polyester bottle according to the present invention can be manufactured, for example, as follows. First, a bottle forming preform is manufactured using the saturated polyester as described above. This preform can be manufactured by a conventionally known method such as injection molding. Next, the bottle forming preform is heated to a temperature suitable for stretching and stretch blow-molded to manufacture a bottle.

[0021]

EFFECTS OF THE INVENTION The saturated polyester bottle according to the present invention has a constitutional unit derived from a specific polyfunctional compound of 0.1 to 0.6 parts by mol, when the dicarboxylic acid compound component unit is 100 parts by mol. It has an intrinsic viscosity [η] of 0.
It is composed of saturated polyester having a content of 5 to 1.0 dl / g. Therefore, even if the bottom of the bottle has a petaloid shape, the bottom is excellent in stress crack resistance, and cracks do not occur at the bottom due to external factors such as temperature, moisture, chemicals, solvents, line lubricants, etc. .. For example,
Even when the carbonated beverage is filled and stored under high temperature and high humidity conditions for a long time, the bottom of the bottle is not damaged.

Further, the transparency and the gas barrier property are not deteriorated as compared with the conventional bottle made of the saturated polyester containing no polyfunctional compound.

[0023]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited to these examples.

In the present invention, the stress crack resistance, transparency, and carbon dioxide permeability coefficient of the bottle are evaluated as follows. [Stress crack resistance] After filling the bottle with 1480 ml of water, the carbon dioxide concentration of this water was adjusted to 4 gas volume by the citric acid-sodium bicarbonate method, and each bottle was adjusted to 23 gas.
After adjusting the temperature to 40 ° C and 40 ° C, an appropriate amount of acetone was sprayed on the bottom of the bottle to observe and evaluate the state of crack generation.

[Transparency] Cut the central part of the body of the bottle and use the haze meter NDH-20D manufactured by Nippon Denshoku Co., Ltd. according to the method according to ASTM D 1003 to measure the haze value (haze) of the test piece. ) Was measured. [CO2 Permeability Coefficient] Using a carbon dioxide permeation tester PERMATRAN C-IV manufactured by MODERN CONTROL (USA), PERMATRA
The carbon dioxide permeation coefficient of a sample consisting of a section (thickness 200 to 300 μm) at the center of the bottle body was measured by the N method under the conditions of a temperature of 23 ° C. and a relative humidity of 0%.

[0026]

Example 1 Polyethylene terephthalate (trimethylolpropane content 0.2 part by mole, intrinsic viscosity [η] 0.8)
7dl / g) Molding machine Dynamerta M- manufactured by Meiki Seisakusho Co., Ltd.
Molding was performed with 70B to obtain a bottle-forming preform. The cylinder temperature setting at this time was 310 ° C.

Next, the preform obtained as described above was stretch blow-molded by an LB-01 molding machine manufactured by CORPOPLAST to obtain a petaloid bottle. The preform was heated to a surface temperature of 100 ° C. with an attached infrared heater.

The physical properties of the bottle thus obtained were measured. The results are shown in Table 1.

[0029]

Example 2 Polyethylene terephthalate (trimethylolpropane content 0.4 part by mole, intrinsic viscosity [η] 0.8)
5 dl / g) was used and a preform for bottle molding was obtained in the same manner as in Example 1 except that the cylinder temperature was set to 315 ° C.

Next, the preform obtained as described above was stretch blow-molded with a LB-01 molding machine manufactured by CORPOPLAST to obtain a petaloid bottle. The preform was heated to a surface temperature of 100 ° C. with an attached infrared heater.

The physical properties of the bottle thus obtained were measured. The results are shown in Table 1.

[0032]

Comparative Example 1 Polyethylene terephthalate (trimethylolpropane content 0 part by mole, intrinsic viscosity [η] 0.85 d
l / g) and a cylinder temperature setting of 290 ° C. was carried out in the same manner as in Example 1 to obtain a bottle-forming preform.

Next, the preform obtained as described above was stretch blow-molded with an LB-01 molding machine manufactured by CORPOPLAST to obtain a petaloid bottle. The preform was heated to a surface temperature of 100 ° C. with an attached infrared heater.

The physical properties of the bottle thus obtained were measured. The results are shown in Table 1.

[0035]

[Comparative Example 2] Polyethylene terephthalate (trimethylolpropane content 1.0 part by mole, intrinsic viscosity [η] 0.8)
6 dl / g) was used, and a preform for bottle molding was obtained in the same manner as in Example 1 except that the cylinder temperature was set to 320 ° C.

Next, the preform obtained as described above was stretch blow-molded by an LB-01 molding machine manufactured by CORPOPLAST to obtain a petaloid bottle. The preform was heated to a surface temperature of 100 ° C. with an attached infrared heater.

The physical properties of the bottle thus obtained were measured. The results are shown in Table 1.

[0038]

[Table 1]

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing an example of a self-supporting bottle (petaloid bottle).

FIG. 2 is a schematic explanatory view showing an example of a round bottom bottle.

[Explanation of symbols]

 1 Bottle 2 Stopper 3 Upper shoulder 4 Body 5 Bottom 6 Support ring

Claims (3)

[Claims] 1. A saturated polyester bottle comprising a spout part, an upper shoulder part, a body part and a self-supporting bottom part, wherein at least the bottom part of the bottle has 100 mol parts of a dicarboxylic acid compound component unit, A saturated polyester comprising a polyfunctional compound component unit in an amount of 0.1 to 0.6 part by mole and having an intrinsic viscosity [η] in the range of 0.5 to 1.0 dl / g. Bottle. 2. The saturated polyester bottle according to claim 1, wherein the polyfunctional compound is trimethylolpropane. 3. The saturated polyester bottle according to claim 1, wherein the bottom portion of the saturated polyester bottle has a petaloid shape.