JP2004263195A - Polyester resin composition and bottle comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester resin composition which has a high crystallization rate, and can form a bottle excellent in transparency as well as can effectively crystallize a bung part of a bottle, and to provide a preform and the bottle comprising the composition. <P>SOLUTION: The composition comprises [A] a polyethylene terephthalate and [B] a polyolefin, [B] the polyolefin being a polypropylene, and contained in an amount of 0.002-200 ppm in the composition. The preform and the bottle are made from the composition. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a polyester resin composition and a preform and a bottle comprising the polyester resin composition, and more particularly, to a polyester resin composition capable of producing a bottle excellent in transparency and heat resistance with high productivity. And a preform and a bottle comprising the polyester resin composition.

Saturated polyesters such as polyethylene terephthalate have been widely used as containers such as bottles because of their excellent transparency and mechanical strength.
In particular, bottles obtained by biaxially stretching polyethylene terephthalate are excellent in transparency, mechanical strength, heat resistance and gas barrier properties, and are used as beverage filling containers (PET bottles) for juices, soft drinks, carbonated drinks, etc. Widely used.

  In order to produce a bottle from such a saturated polyester, generally, a saturated polyester is injection-molded to form a preform, and then the preform is inserted into a mold having a predetermined shape and stretch blow-molded to form a cylinder. A bottle having a plug portion and a body portion is obtained by forming a portion.

  Since the bottle obtained in this way, especially a bottle used for beverages such as juice, is required to have heat resistance capable of coping with the heat sterilization treatment of the contents, the bottle is usually further heat-treated (heat-set) after blow molding. To improve heat resistance.

  In addition, in the bottle obtained in this manner, the plug portion is in an unstretched state, and is inferior in mechanical strength and heat resistance as compared with the trunk portion in the stretched state. For this reason, the plug portion of the preform is usually heated and crystallized before blow molding, or the bottle obtained by blow molding is subjected to heat treatment (heat setting) to obtain the mechanical strength and the like of the plug portion. Heat resistance etc. are improved.

  By the way, bottles made of polyester resin (especially polyethylene terephthalate) have been increasing in size in recent years, and the manufacturing process of the bottles has been sped up. It is difficult to perform the heat setting in a short time, and it has been desired to speed up the crystallization process of the bottle stopper in order to speed up the bottle manufacturing process and improve productivity.

  As such a polyester resin having a large crystallization rate, a polyester resin composition comprising a newly produced polyester resin and a repropolyester resin which is once formed into a bottle shape and then shredded is used. Although the bottle obtained from the polyester resin composition can increase the crystallization speed of the plug, there is a problem that the transparency of the obtained bottle is reduced.

  For this reason, the appearance of a polyester resin composition, particularly a polyethylene terephthalate resin composition, which is excellent in transparency and mechanical strength and has a high heating crystallization rate, is desired.

The present invention has been made in view of the prior art as described above, and has a high crystallization rate, can efficiently crystallize the plug portion of the bottle, and form a bottle having excellent transparency. It is an object of the present invention to provide a polyester resin composition which can be used, and a preform and a bottle comprising the polyester resin composition.

The polyester resin composition of the present invention,
[A] polyethylene terephthalate comprising a unit derived from a dicarboxylic acid containing terephthalic acid or an ester derivative thereof, and a diol containing ethylene glycol or an ester derivative thereof,
[B] consisting of polyolefin,
This [B] polyolefin is polypropylene, and 0.002 to 2 in the composition.
It is characterized in that it is contained in an amount of 00 ppm.

The preform and the bottle according to the present invention comprise the polyester resin composition as described above.
The preform according to the present invention is obtained by injection molding the above polyester resin composition. The bottle according to the present invention is preferably manufactured by heating and crystallizing the plug portion of the preform, followed by biaxial stretch blow molding.

  The polyester resin composition according to the present invention as described above has a high heating crystallization rate, and can form a bottle of a preform at a high speed when forming a bottle, and furthermore have high transparency and heat resistance. An excellent body can be formed.

  Therefore, a bottle excellent in transparency and heat resistance can be manufactured with high productivity from this polyester resin composition.

  The polyester resin composition according to the present invention has a crystallization rate suitable for bottle molding, is excellent in transparency and heat resistance, and furthermore, is capable of producing a bottle having excellent heat resistance and mechanical strength of a plug portion at a high speed. And can be manufactured with high productivity.

The polyester resin composition according to the present invention comprises [A] polyethylene terephthalate and [B] polyolefin.
First, each of these components will be described.

[A] Polyethylene terephthalate [A] Polyethylene terephthalate used in the present invention comprises dicarboxylic acid such as terephthalic acid or an ester derivative thereof (for example, lower alkyl ester, phenyl ester, etc.) and ethylene glycol or an ester derivative thereof (for example, monocarboxylic acid). And a unit derived from a diol such as ester ethylene oxide.

This polyethylene terephthalate [A] may contain a unit derived from a dicarboxylic acid and / or diol other than the above, if necessary.
Specific examples of such dicarboxylic acids other than terephthalic acid include phthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, and the like. These can also be used as their ester derivatives.

As diols other than ethylene glycol, specifically,
Aliphatic glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, trimethylene glycol (propylene glycol), butanediol, pentanediol, neopentyl glycol, hexamethylene glycol, dodecamethylene glycol, and polyethylene glycol;
Alicyclic glycols such as cyclohexane dimethanol,
Examples thereof include aromatic diols such as bisphenols and hydroquinone. These may be used as their ester derivatives.

  Also, a combination of two or more of these may be used. The polyethylene terephthalate [A] used in the present invention contains units derived from diols other than ethylene glycol in an amount of 0.1 to 3 mol%, particularly when the units derived from diol are 100 mol%. Is also good.

Diethylene glycol is preferred as such another diol.
The [A] polyethylene terephthalate used in the present invention may contain a small amount of a unit derived from a polyfunctional compound such as trimesic acid, pyromellitic acid, trimethylolethane, trimethylolpropane, trimethylolmethane, and pentaerythritol, if necessary. For example, it may be contained in an amount of 2 mol% or less.

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

  The intrinsic viscosity IV (measured in o-chlorophenol at 25 ° C.) of the polyethylene terephthalate [A] used in the present invention is usually 0.3 to 1.5 dl / g, preferably 0.5 to 1.5 dl / g. It is desirable that

The polyethylene terephthalate [A] used in the present invention is produced from the above dicarboxylic acid and diol by a conventionally known production method.
In the present invention, as such polyethylene terephthalate [A], "raw polyethylene terephthalate" which is usually commercially available in pellet form is used, and if necessary, "repropolyethylene terephthalate" is used together with the raw polyethylene terephthalate. You may. Specifically, polyethylene terephthalate [A] may contain "lipopolyethylene terephthalate" in an amount of 1 to 50% by weight.

In the present specification, "raw polyethylene terephthalate" is a polyethylene terephthalate that is produced in the form of pellets from a dicarboxylic acid and a diol, and that has no history of being molded into a bottle or a preform by being passed through a molding machine in a heated and molten state. It is. "Repropolyethylene terephthalate" is obtained by pelletizing polyethylene terephthalate obtained by passing such a raw material polyethylene terephthalate at least once or more through a molding machine in a heated and molten state. As described above, the process of “passing the raw material polyethylene terephthalate through the molding machine in a heated and melted state” involves heating and melting pellets (chips) made of the raw material polyethylene terephthalate to form a desired shape such as a preform or a bottle.
And done by

[B] Polyolefin The polyester resin composition according to the present invention contains polyolefin [B] as a component that promotes heat crystallization.

  As the polyolefin [B], a conventionally known polyolefin is used without any particular limitation, and a polyolefin produced from the following olefin by a conventionally known production method is used. Such olefins include, for example, ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-octene and the like.

  The polyolefin used in the present invention may be any of these homopolymers, random copolymers, and block copolymers. Further, a unit derived from a polyunsaturated compound such as a conjugated diene and a non-conjugated diene may be contained as a copolymer component. In the present invention, as the polyolefin [B], polypropylene is preferable.

Polyester resin composition The polyester resin composition according to the present invention comprises the above-mentioned [A] polyethylene terephthalate,
[B] consisting of polyolefin,
The polyolefin [B] is contained in the composition in an amount of 0.002 to 200 ppm.

If the amount of the polyolefin [B] is less than 0.002 ppm in the composition, the effect of accelerating the heat crystallization is not sufficiently exhibited, while if it exceeds 200 ppm, the transparency of the molded product is liable to be lowered.

  Such a polyester resin composition according to the present invention has an appropriate crystallization rate such that a bottle can be efficiently produced. Specifically, the polyester resin composition desirably has a temperature-rise half-crystallization time of 10 to 200 seconds, preferably 20 to 150 seconds.

  In addition, for the heating half-crystallization time, the dried sample was melted by heating at 290 ° C. for 5 minutes, then rapidly cooled to 50 ° C. at a cooling rate of 320 ° C./min and left for 5 minutes to produce an amorphous sample. After that, the amorphous sample is heated and held at 140 ° C. at a rate of 320 ° C./min to measure the time required for semi-crystallization.

  In order to prepare a polyester resin composition from polyethylene terephthalate [A] and polyolefin [B], any known method can be employed. For example, polyethylene terephthalate [A] and polyolefin [B] are directly mixed and melt-kneaded by a mixer such as a tumbler blender or a Henschel mixer, or polyethylene terephthalate [A] and polyolefin [B] are previously melt-kneaded. Then, a masterbatch containing a high concentration of polyolefin [B] is prepared in advance, and a polyester resin composition can be prepared by a method of appropriately blending the masterbatch with polyethylene terephthalate [A].

  The polyester resin composition according to the present invention as described above, if necessary, may contain other additives such as a coloring agent, an antioxidant, an ultraviolet absorber, an antistatic agent, a flame retardant, and a lubricant. Good. Further, these other additives may be blended into the polyester resin composition as a master batch prepared in advance from these additives and the polyester resin composition.

Preforms and Bottles The preforms and bottles according to the present invention are composed of the polyester resin composition as described above, and the preforms are obtained by injection molding the polyester resin composition.

  A bottle can be obtained by biaxially stretch-blow molding this preform. In the present invention, it is preferable to manufacture a bottle by heating and crystallizing the plug portion of the preform, heating and softening the body and bottom of the preform, and then performing biaxial stretch blow molding.

The heating and crystallization of the preform plug is desirably performed at a temperature of 100 to 200C, preferably 120 to 180C.
The softening of the body and bottom of the preform by heating is usually performed at a temperature which is higher than the glass transition temperature (Tg) of polyethylene terephthalate [A] and lower than the crystallization temperature (Tc). It is desirably carried out at 160 ° C, preferably at 80 to 140 ° C.

  The biaxial stretch blow molding of the preform is preferably performed at a resin temperature of 70 to 150 ° C, preferably 80 to 140 ° C, and a mold temperature of room temperature to 220 ° C, preferably 90 to 180 ° C.

  When the bottle thus obtained is subjected to a heat treatment (heat setting), the heat resistance is further improved. The heat setting is desirably performed at a temperature of 100 to 240C, preferably 110 to 220C.

  In the present invention, the heating and crystallization treatment of the preform plug portion as described above can be performed at high speed, and the biaxial stretch blow molding and heat setting can be performed without reducing the transparency of the body of the bottle. It can be carried out.

  In the present invention, the bottle is manufactured by performing biaxial stretch blow molding of the preform without heating and crystallizing the plug portion of the preform, and then the plug portion of the obtained bottle is subjected to heat treatment (heat setting). ).

EXAMPLES Next, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples.

In the examples, each characteristic was measured as follows.
Intrinsic viscosity (IV)
An 8 g / dl sample solution was prepared using an orthochlorophenol solvent, and the intrinsic viscosity [IV] was calculated from the solution viscosity measured at 25 ° C.
Transparency (haze value)
The dried sample was molded into a 5 mm-thick square plate at a mold temperature of 10 ° C. using an injection molding machine having a cylinder temperature of 280 ° C., and the transparency of the molded product was compared by a haze value (light diffuse reflectance of white light). .
Temperature rise crystallization speed The temperature rise half crystallization time was measured as described above. The shorter the half-crystallization time, the more efficiently the crystallization proceeds.
A 1.5 liter bottle was left under a condition of 40 ° C. and 90% humidity for one week, filled with hot water of 90 ° C. for 10 minutes, and the content before and after filling was measured.

  From the content before and after filling, the shrinkage (%) was determined by the following equation.

From the shrinkage (%) value thus obtained, the heat resistance was evaluated according to the following criteria.
○… 0 ≦ shrinkage ratio (%) <0.5
×: 0.5 ≦ shrinkage rate (%)
Bottle appearance of 1.5 l bottle was measured under (bottom side) from the haze value of the height bottle aspect of 83 mm (light diffuse reflectance of white light).

From the haze value (%), the appearance of the bottle was evaluated as follows.
0 ≦ Haze value (%) <5
×… 5 ≦ Haze value

  Intrinsic viscosity [IV] = 0.775 dl / g, diethylene glycol content; 1.33% by weight of polyethylene terephthalate (A-1) and polypropylene (B) (“J300” manufactured by Mitsui Petrochemical Industries, Ltd.) A polyester resin composition containing the polypropylene (B) in an amount of 100 ppm (parts by weight) was obtained.

  After melting this polyester resin composition, injection molding was performed to form a square plate, and the transparency of this square plate was measured. Next, a bottle was formed from the polyester resin composition as described below.

  Using an injection molding machine M-100A (manufactured by Meiki Seisakusho), a 28 mmφ preform was molded under the conditions of a cylinder set temperature of 280 ° C. and a mold temperature of 10 ° C. The plug part of the obtained preform was crystallized by heating at 170 ° C. for 5 minutes in an oil bath, and then the body and bottom of the preform were heated and softened at 110 ° C.

Then, the preform is stretch-blow-molded by a molding machine LB01 (manufactured by CORPOPLAST) at a stretching temperature of 110 ° C. and a blow mold temperature of 150 ° C.
5 liter bottles were molded.

This bottle was evaluated for heat resistance and appearance as described above. Table 1 shows the results.
Examples 2 to 6
A polyester resin composition, a square plate and a bottle were obtained in the same manner as in Example 1 except that the content of (B) polypropylene was changed to the amount shown in Table 1. Table 1 shows the results.

Comparative Example 1
In Example 1, a square plate and a bottle containing only polyethylene terephthalate (A-1) without containing polypropylene (B) were produced in the same manner as in Example 1.

Table 1 shows the results.
Comparative Example 2
(A-2) polyethylene terephthalate having an intrinsic viscosity [IV] different from (A-1) polyethylene terephthalate used in Example 1 (intrinsic viscosity [IV] = 0.706 dl / g, diethylene glycol content; 1.33% by weight) Example 1 except that a polyester composition comprising
In the same manner as in the above, a polyester resin composition, a square plate and a bottle were obtained. Table 1 shows the results.

Comparative Example 3
A polyester resin composition, a square plate and a bottle were obtained in the same manner as in Example 1 except that the content of polypropylene (B) was changed to 500 ppm.

  Table 1 shows the results.

Claims (4)

[A] polyethylene terephthalate comprising a unit derived from a dicarboxylic acid containing terephthalic acid or an ester derivative thereof, and a diol containing ethylene glycol or an ester derivative thereof,
[B] consisting of polyolefin,
This [B] polyolefin is polypropylene, and 0.002 to 2 in the composition.
A polyester resin composition, which is contained in an amount of 00 ppm.   A preform obtained by injection molding the polyester resin composition according to claim 1.   A bottle comprising the polyester resin composition according to claim 1.   The polyester resin composition according to claim 1 is injection-molded to form a preform, and then the plug portion of the preform is heated and crystallized, followed by biaxial stretch blow molding. Bottle manufacturing method.