JP2000095927A - Polyester blow molded part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester blow molded part having a high crystallinity, impact resistance and transparency. SOLUTION: A polyester blow molded part is prepared by blending from 95 to 99.99 wt.% polyester (A) which comprises a naphthalenedicarboxylic acid as the main acid component and an ethylene glycol as the main glycol component and from 5 to 0.01 wt.% polyester block copolymer (B) which comprises an aromatic polyester and/or an aliphatic polyester as a soft segment and an aromatic polyester as a hard segment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester hollow molded article, and more particularly, to a polyester molded article obtained by blending a polyester-ester block copolymer with polyethylene naphthalenedicarboxylate, which has excellent crystallinity, impact resistance and transparency. The present invention relates to a polyester hollow molded article.

[0002]

2. Description of the Related Art Polyethylene naphthalenedicarboxylate has higher heat resistance than polyethylene terephthalate,
Due to its excellent basic properties such as gas barrier properties and chemical resistance, it has recently been used for bottles (containers) or sheet materials, and many proposals have been made by blending with polyethylene terephthalate or using it alone. Above all, the use amount of beverage bottles is gradually increasing from the viewpoint of heat resistance and ultraviolet absorption performance.

[0003] However, although polyethylene naphthalenedicarboxylate has excellent physical properties, its crystallinity is inferior to that of polyester currently on the market, so that the molding cycle in injection molding applications is delayed, and when a hollow molded article is formed. The impact resistance of the molded product was not sufficient due to the insufficient crystallization promotion of the mouth and the like, and the occurrence of delamination derived from the molecular structure of polyethylene naphthalenedicarboxylate itself. . In order to solve these problems, a method of copolymerizing polyethylene naphthalenedicarboxylate with a long-chain polyol such as polyoxyalkylene glycol (Japanese Patent Laid-Open No.
48758) and a method of blending a polyethylene naphthalenedicarboxylate polymer with a polyester block copolymer using a polyoxyalkylene glycol for the soft segment (Japanese Patent Application Laid-Open No. 63-238155).

[0004]

However, the copolymerization of polyoxyalkylene glycol causes problems in the polycondensation step due to the problem of thermal stability, and the copolymerization of polyester blocks using polyoxyalkylene glycol as a soft segment. Blending with a polymer makes it difficult to obtain a transparent molded article due to compatibility problems, and is not always sufficient in terms of improving crystallinity and impact resistance.

An object of the present invention is to solve the above problems. More specifically, the present invention is intended to reduce the viscosity of a polyethylene naphthalenedicarboxylate polymer during injection molding while being excellent in crystallinity, impact resistance and transparency. An object of the present invention is to provide a polyester hollow molded article which is possible and can reduce regenerated acetaldehyde due to shear heat generation or the like.

[0006]

That is, the present invention provides 95 to 99.99% by weight of a polyester (A) containing naphthalenedicarboxylic acid as a main dicarboxylic acid component and ethylene glycol as a main diol component, and aromatic polyester and / or 5 to 0.01% by weight of a polyester block copolymer (B) having an aliphatic polyester as a soft segment and an aromatic polyester as a hard segment
It is a polyester hollow molded article consisting of:

The naphthalenedicarboxylic acid as the main dicarboxylic acid component constituting the polyester (A) in the present invention is 2,6-naphthalenedicarboxylic acid and / or 2,7-naphthalenedicarboxylic acid, and the term “main” means all. 70 mol% or more based on the dicarboxylic acid component,
It is preferably at least 80 mol%.

[0008] Components which can be copolymerized in the range of 30 mol% or less include aromatic acids such as oxalic acid, malonic acid, succinic acid, isophthalic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylsulfondicarboxylic acid, and diphenyletherdicarboxylic acid. Alicyclic dicarboxylic acids such as aromatic dicarboxylic acid, cyclohexanedicarboxylic acid, decalin dicarboxylic acid, and teleralin dicarboxylic acid; and oxy acids such as glycolic acid and p-oxybenzoic acid.

The diol component is composed of at least 70 mol% of ethylene glycol with respect to all dicarboxylic acid components, but other diol components may be copolymerized within a range of less than 30 mol%. Examples of such a diol component include diethylene glycol, triethylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, cyclohexanedimethanol, and bisphenol A.

When the dicarboxylic acid component and the diol component are 3
When it is copolymerized in an amount exceeding 0 mol%, physical properties inherent in polyethylene naphthalenedicarboxylate, for example, gas barrier properties and heat resistance are poor.

In producing the polyester (A), for example, a direct esterification method or a transesterification method can be used as the production method. Known techniques can be used for the transesterification catalyst and the polycondensation catalyst, and examples of the catalyst include metal compounds generally known as a transesterification catalyst and a polycondensation catalyst for polyethylene terephthalate. Specific examples of transesterification catalysts include manganese compounds, calcium compounds, magnesium compounds,
Examples thereof include a titanium compound, a zinc compound, a sodium compound, a potassium compound, a cerium compound, and a lithium compound, and a cobalt compound that also acts as a color-matching agent may be optionally added. Specific examples of the polycondensation catalyst include a germanium compound and an antimony compound.

The polyester (A) produced by the transesterification method and / or the direct esterification method preferably contains a phosphorus compound as a stabilizer. Examples of the phosphorus compound include orthophosphoric acid, phosphorous acid, and phosphorus. Acid esters or phosphoric acid triesters are used.

On the other hand, the polyester block copolymer (B) in the present invention comprises a soft segment and a hard segment.

[0014] The soft segment comprises an aromatic polyester and / or an aliphatic polyester. The soft segment preferably comprises 60 to 100% by mole of an aromatic dicarboxylic acid and 40 to 0% by mole of an aliphatic dicarboxylic acid, as a ratio of the polyester constituting the soft segment to the total dicarboxylic acid component. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, and phthalic acid, with isophthalic acid and phthalic acid being preferred.

The aliphatic dicarboxylic acids include those having 6 to 6 carbon atoms.
12 aliphatic dicarboxylic acids are preferred, azelaic acid,
Sebacic acid, decanedicarboxylic acid or lower alkyl ester derivatives thereof are exemplified as preferred.

As the diol component constituting the soft segment, an aliphatic α, ω-diol having 6 to 12 carbon atoms is preferable. Aliphatic α, ω-diol is HO (CH ₂ ) _n OH
(Where, 6 ≦ n ≦ 12).

The hard segment constituting the polyester block copolymer (B) comprises an aromatic dicarboxylic acid having an acid component of 70 mol%, preferably 80 mol% or more based on the total dicarboxylic acid component, and having 2 to 4 carbon atoms. Aliphatic α, ω-
An aromatic polyester containing diol and / or 1,4-cyclohexanedimethanol as a diol component in an amount of 70 mol% or more, preferably 80 mol% or more, based on all dicarboxylic acid components. The polyester preferably has a melting point of 1
The temperature is at least 80 ° C, more preferably at least 200 ° C.

Examples of the aromatic dicarboxylic acid constituting the hard segment include terephthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4′-diphenyldicarboxylic acid, and α, ω-diol is ethylene glycol;
Trimethylene glycol and tetramethylene glycol.

As the aromatic polyester constituting the hard segment, polytetramethylene terephthalate, polytetramethylene-2,6-naphthalenedicarboxylate and poly1,4 are preferable because of their good crystallinity and high crystallization speed. -Cyclohexynesan dimethylene terephthalate is preferred.

The weight ratio of the soft segment to the hard segment constituting the polyester block copolymer (B) is preferably from 90:10 to 30:70.

The polyester block copolymer (B) can be obtained by melt-mixing a polyester serving as a soft segment component and a polyester serving as a hard segment component under reduced pressure using a reaction tank or a reaction extruder.

The blend ratio of the polyester (A) and the polyester block copolymer (B) is (A) / weight ratio.
(B) is 95/5 to 99.99 / 0.01, preferably 98/2 to 99.9 / 0.1. If the blend ratio of the polyester (A) is less than 95% by weight, heat resistance and the like, which are inherent properties of polyethylene naphthalenedicarboxylate, are reduced. If the blend ratio of the polyester block copolymer (B) is less than 0.01% by weight, the improvement in crystallinity and the improvement in impact resistance are insufficient.

The polyester hollow molded article of the present invention preferably has a breakage rate of 15% or less when dropped. The failure rate is determined from the number of damages when four volumes of carbonated water are filled into a polyester hollow molded article and dropped from a height of 1 m onto concrete having an inclination of 30 degrees.

When the polyester hollow molded article obtained by the present invention is measured with a differential scanning calorimeter, the temperature-rise crystallization peak temperature (Tc) preferably satisfies the following expression. Tc ≦ 69.7 × IV + 169.8 where IV is the intrinsic viscosity of the polyester (A).

The temperature rise crystallization peak temperature is the peak apex temperature corresponding to the temperature rise crystallization exotherm at the time of temperature rise by the differential scanning calorimeter. The temperature rise crystallization peak temperature means that the crystallization rate at the time of temperature rise is promoted as the temperature becomes lower, and when the temperature exceeds the range of the above formula or when the temperature rise crystallization peak is not detected, the crystallization is performed. The promoting effect is not expressed, which is not preferable.

It is preferable that the peak temperature due to the heat of crystallization at the time of temperature drop is not detected, or even if it is detected, it is not higher than 205 ° C. When the peak temperature corresponding to the crystallization exotherm at the time of the temperature drop is detected exceeding 205 ° C., it means that the crystallization speed when solidifying from the molten state is high, and the transparency of the hollow molded article or the like is required. It is not preferable for use in injection molding of a preform because whitening occurs when the preform is cooled in a mold.

The acetaldehyde content of the hollow polyester molded article is preferably 30 ppm or less. In particular, when the hollow molded article is used for a food packaging container or the like, a large content of acetaldehyde is not preferable because it causes a problem in flavor.

The content of acetaldehyde can be reduced by producing the polyester (A) by melt polymerization, followed by a drying step or by performing solid phase polymerization. By using the polyester block copolymer having the soft segment structure of above, the viscosity of polyethylene naphthalenedicarboxylate at the time of injection molding can be reduced, and the acetaldehyde can be further reduced.

The body haze of the hollow polyester molded article is 8
% Is preferable. When the body haze exceeds 8%, the transparency is lowered and the appearance as a product is inferior. The body thickness of the hollow molded body is the capacity,
Although it depends on the application, it is usually 200 to 500 μm.

Although a conventionally known blend with a polyester block copolymer having polytetramethylene glycol as a soft segment has a crystallization accelerating effect, since it is a blend with a polyether component, the compatibility with the polyester is sufficient. Rather, it is difficult to obtain a molded product with high transparency, and measures such as increasing the residence time of injection molding and increasing the temperature of injection molding are necessary to improve transparency. However, in that case, the resulting molded product is inferior in hue, mechanical strength and the like, which is not preferable. In addition, the blending amount has to be reduced because the compatibility is inferior, and it cannot be said that it is sufficient from the viewpoint of improving the impact resistance.

The polyester hollow molded article of the present invention has a good compatibility with polyethylene naphthalene dicarboxylate because a polyester block copolymer in which the soft segment is made of polyester is blended. Obtainable. Also, since a highly transparent polyester hollow molded article can be obtained in a short time, the amount of acetaldehyde contained can be reduced.

The intrinsic viscosities of the polyester (A) and the polyester block copolymer (B) are each 0.4 to 0.5.
8, preferably 0.3 to 1.2. If the intrinsic viscosity of the polyester (A) is less than 0.4, it is not preferable because the mechanical strength of the obtained polyester hollow molded article is reduced. When the intrinsic viscosity exceeds 0.8,
Due to the high melt viscosity of the polyethylene naphthalene dicarboxylate, the polymer may be deteriorated in the hue, the molecular weight may be reduced due to the problem of heat generation at the time of blending with the polyester block copolymer (B) due to the production process, and undesirable decomposition products may be reduced. It is not preferable because the increase becomes remarkable. If the intrinsic viscosity of the polyester block copolymer (B) is less than 0.3, blending with polyethylene naphthalenedicarboxylate is not preferred because the effects of promoting crystallization and improving impact resistance are not sufficient. When the intrinsic viscosity is more than 1.2, the melt viscosity becomes high, so that it takes a long time for melt mixing at the time of injection molding, which is not preferable.

The melting point of the polyester block copolymer (B) is preferably 180 ° C. or higher. 180 melting point
When the melting point of the polyester block copolymer is less than 180 ° C., it is not only that the polyester block copolymer has a melting point of less than 180 ° C. Since the properties are close to the properties of a polymer, the effect of promoting the crystallinity and the effect of improving the impact resistance of the obtained polyester hollow molded article are not satisfactory.

The polyester resin composition for forming the polyester hollow molded article of the present invention contains various additives such as an antioxidant, an ultraviolet absorber, an antistatic agent, a dye and a pigment, if necessary. Is also good. The polyester resin composition can be obtained by a known method, and a polyester hollow molded article can also be obtained by a known method.

[0035]

The present invention will be described in more detail with reference to the following examples. Various characteristics were measured as follows.

Intrinsic viscosity: Calculated from the solution viscosity measured at 35 ° C. using a phenol / tetrachloroethane = 6/4 (weight ratio) mixed solvent.

Drop impact test: After filling the hollow molded body with 4 volumes of carbonated water, it was dropped from a height of 1 m onto concrete having a gradient of 30 degrees to determine the breakage rate. The number of samples is 20.

Temperature rising crystallization peak temperature: Corresponding to the temperature rising crystallization exothermic peak when 10 mg of a polymer was measured at a temperature rising rate of 5 ° C./min using a TA Instrument 2920 type differential scanning calorimeter. From the peak peak temperature.

Haze: After drying the polymer at 160 ° C. for 5 hours, a preform of 55 g was molded at a molding temperature of 305 ° C. using an injection molding machine 100DM manufactured by Meiki Seisakusho, and this was blow-stretched. A hollow molded body having a volume of 1.55 liter and a body thickness of 300 μm was obtained. The body of the hollow molded body was cut out and measured with a turbidity meter manufactured by Nippon Denshoku Industries Co., Ltd. If the polymer is not formed into a hollow molded product, 3
The sheet was formed into a sheet of 00 μm and measured by the above method.

Acetaldehyde content: The polymer was freeze-pulverized and measured by HS-GC manufactured by Hitachi, Ltd.

Reference Example 1 Production of Polyester (A) 2,6-Naphthalenedicarboxylic acid dimethyl ester 10
0 parts by weight and 51 parts by weight of ethylene glycol are 0.014 parts by weight (20 mmol%) of calcium acetate monohydrate, 0.044 parts by weight (50 mmol%) of magnesium acetate tetrahydrate, and cobalt acetate tetrahydrate A transesterification reaction was carried out by a conventional method in the presence of 0.005 parts by weight (5 mmol%), and 1.5 parts by weight (35 mmol%) of a 1% solution of germanium dioxide in ethylene glycol and 0.057 parts by weight of trimethyl phosphate before the completion of the reaction. Parts by weight (100 mmol%) were added. Then, after performing a polycondensation reaction at 295 ° C. under a high vacuum of 1 mmHg or less to obtain a polymer having an intrinsic viscosity of 0.47, solid-state polymerization is further performed by a conventional method to obtain a polyester (A) having an intrinsic viscosity of 0.65. Was.

Reference Example 2 Production of Polyester Block Copolymer (B) 100 parts by weight of dimethyl isophthalate, 6 parts by weight of dimethyl sebacate, and 74 parts by weight of 1,6-hexanediol were 0.15 parts by weight of dibutyltin diacetate. (80 mmol%) to remove by-produced methanol to terminate the transesterification reaction, followed by polycondensation at 260 ° C under a high vacuum by a conventional method to obtain an amorphous polyester. 70 parts by weight of the obtained amorphous polyester was separately 30 parts by weight of polybutylene terephthalate polymerized from dimethyl terephthalate and 1,4-butanediol, and 250 ° C., 1 mmH
g of phenylphosphonic acid (1.5 times mol% based on dibutyltin diacetate) to terminate the redistribution reaction, and to give an intrinsic viscosity of 1.04.
To obtain a polyester block copolymer (B). The melting point of the obtained polyester block copolymer (B) is 210
° C.

Example 1 99.0 parts by weight of the polyester (A) obtained in Reference Example 1 and 1.0 part by weight of the polyester block copolymer (B) obtained in Reference Example 2 were dry-blended. A preform obtained by injection molding using an injection molding machine 100DM manufactured by Kiki Seisakusho Co., Ltd. was blow molded to obtain a hollow molded body having an inner volume of 1.55 liter and a body thickness of 300 μm. The injection molding conditions were set at a cylinder temperature of 305 ° C., the molding cycle was 30 seconds, and the blow molding was performed using an LB01 blow molding machine manufactured by Corpoplast. Table 1 shows the measurement results of the temperature rise crystallization temperature, haze, impact strength, and acetaldehyde content of this hollow molded body.

Comparative Example 1 Polyester (A) was injection-molded in the same manner as in Example 1 without blending the polyester block copolymer, followed by blow molding to obtain an inner volume of 1.55 liter and a body thickness. A hollow molded body of 300 μm was obtained. Table 1 shows the measurement results of the physical properties of the hollow molded article.

Example 2 Polyester (A) 99.9
Using a weight part and 0.1 part by weight of the polyester block copolymer (B), dry friend, injection molding and blow molding were carried out in the same manner as in Example 1 to obtain a hollow molded body. Table 1 shows the measurement results of the physical properties of the hollow molded article.

Example 3 Polyester (A) 99.8
Part by weight and 0.2 part by weight of the polyester block copolymer (B) were dry-blended, injection-molded and blow-molded in the same manner as in Example 1 to obtain an inner volume of 1.55 liter and a body thickness of 3
A 00 μm hollow molded body was obtained. Table 1 shows the results of measuring the physical properties of the hollow molded article.

Comparative Example 2 In place of the polyester block copolymer (B), 40% by weight of polytetramethylene glycol having an average molecular weight of 1000 was used as a soft segment, and 60% by weight of an aromatic polyester made of polybutylene terephthalate was used as a hard segment. A hollow molded article was obtained in the same manner as in Example 1 except that 1.0 part by weight of the polyester block copolymer was used. The physical properties of this hollow molded body were measured. Table 1 shows the results.

Comparative Example 3 Polyester (A) 93.0
A hollow molded body was obtained in the same manner as in Example 1 by using 7.0 parts by weight of the polyester block copolymer (B) by weight. Table 1 shows the measurement results of the physical properties of the hollow molded article. The haze value was 21%, and although the crystallinity was improved, the compatibility was deteriorated, and a polymer having low transparency was obtained.

Comparative Example 4 Aromatic polyester 50 comprising 50% by weight of polyoxytetramethylene glycol having an average molecular weight of 1500 as a soft segment and 50% by weight of polybutylene terephthalate as a hard segment
The same procedure as in Example 1 was repeated using 0.2 parts by weight of a polyester block copolymer consisting of 0.2% by weight and 99,8 parts by weight of polyester (A) to obtain an inner volume of 1.55 liter and a body thickness of 300 μm. A hollow molded body was obtained. Table 1 shows the measurement results of the physical properties of the hollow molded article.

[0050]

[Table 1]

As is evident from the examples and comparative examples, the crystallization characteristics are improved by blending a polyester block copolymer having a commercially available aliphatic polyether as a soft segment with the polyester (A). However, the compatibility is poor and only a polymer with low transparency can be obtained.

[0052]

According to the present invention, a hollow molded article having excellent crystallinity, impact resistance and transparency can be obtained.

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Hiroki Nagano 77 Term Kitayoshida-cho, Matsuyama-shi, Ehime Pref. CF172 GG01

Claims (7)

[Claims] 1. 95 to 99.99% by weight of a polyester (A) containing naphthalenedicarboxylic acid as a main dicarboxylic acid component and ethylene glycol as a main diol component.
And polyester block copolymer (B) having an aromatic polyester and / or an aliphatic polyester as a soft segment and an aromatic polyester as a hard segment
A polyester hollow molded article comprising 5 to 0.01% by weight. 2. The polyester hollow molded article according to claim 1, which is excellent in impact resistance and has a breakage rate of 15% or less when the hollow molded article is dropped in a drop impact test. 3. The polyester hollow container according to claim 1, wherein the polyester has excellent crystallinity and a temperature-rise crystallization peak temperature (Tc) measured by a differential scanning calorimeter satisfies the following expression. Tc ≦ 69.7 × IV + 169.8 [where IV indicates the intrinsic viscosity of the polyester (A). ] 4. The polyester hollow molded article according to claim 1, wherein the acetaldehyde content is 30 ppm or less. 5. The polyester hollow molded article according to claim 1, which has a body haze of 8% or less. 6. The polyester (A) having an intrinsic viscosity of 0.4
The polyester hollow molded article according to claim 1, wherein the polyester block copolymer (B) has an intrinsic viscosity of 0.3 to 1.2. 7. The polyester hollow molded article according to claim 1, wherein the melting point of the polyester block copolymer (B) is 180 ° C. or higher.