JPH071562A - Production of extrusion blow molded product of polyester resin - Google Patents

Abstract

PURPOSE:To hold the properties of a thermoplastic elastomer and to improve high viscosity by the addition of a proper amt. of a branching agent by subjecting a polyester resin having specific characteristics to extrusion molding within a predetermined temp. range and further subjecting the extruded resin to blow molding within a specific temp. range. CONSTITUTION:A polyester resin is constituted of a hydroxy compd. having a specific structure selected from aliphatic dicarboxylic acid, aliphatic diol, a dihydroxy compd. and a monohydroxyl compd. and containing 0.6-2.5 equivalent of a branching agent per 100mol of aliphatic dicarboxylic acid and characterized by that a melt flow index X(g/10min) is within a range of 0.1<X<2.5 at temp. 10-20 deg.C higher than the m.p. thereof and Young's modulus E'(kgf/cm<2>) is within a range of 1X10<6E'<1X10<9> at temp. 5-20C lower than the m.p. thereof. This resin is extruded within the temp. range 10-20 deg.C higher than its m.p. to be preformed and the preformed resin is subjected to blow molding at temp. 5-20 deg.C lower than the m.p. thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an extrusion blow molded product of polyester resin.

[0002]

2. Description of the Related Art In recent years, thermoplastic elastomers having rubber elasticity at room temperature and plasticized at high temperatures have been developed, and various types of thermoplastic elastomers have been manufactured and marketed. This thermoplastic elastomer does not require a long-time cross-linking step unlike the conventional rubber, and can be molded by a molding method such as injection molding or extrusion molding.

Particularly, as described in JP-A-3-97723, a polyester resin containing a dihydroxy compound having a p-terphenyl or p-quaterphenyl skeleton or a monohydroxy compound as a constituent component is a hydroxy compound. The transition point (melting point) from the crystalline state to the liquid crystal state is extremely high, reflecting its characteristic molecular structure, resulting in extremely strong physical crosslinks with high heat resistance, and excellent heat resistance and mechanical properties. It is a thermoplastic elastomer and has excellent processability such as injection molding and extrusion molding.

[0004]

However, a method for producing an extrusion blow-molded product of the obtained polyester resin having high viscosity has not been clarified.

The present invention is intended to solve the above-mentioned problems, and an object thereof is extrusion blow molding of a polyester resin having properties as a thermoplastic elastomer and having a high viscosity by adding an appropriate amount of a branching agent. It is to provide a manufacturing method of a product.

[0006]

The method for producing an extrusion blow-molded article of a polyester resin according to the present invention comprises an aliphatic dicarboxylic acid represented by the following general formula [I], an aliphatic diol, and the following general formula [II ] At least one hydroxy compound selected from the group consisting of a dihydroxy compound represented by the following formula and a monohydroxy compound represented by the following general formula [III], and a polyol having 3 to 6 hydroxyl groups, 3 to 4 A polycarboxylic acid having a carboxyl group and at least one branching agent selected from the group consisting of oxyacids having a hydroxyl group and a carboxyl group and having 3 to 6 groups are used as constituent components. In the polyester resin containing 0.6 to 2.5 equivalents per 100 mol of the aliphatic dicarboxylic acid, the melting point of the polyester resin is 1
When the temperature is 0 to 20 ° C. higher, the melt flow index χ (g / 10 minutes) is in the range of 0.1 <χ <2.5, and when the temperature is 5 to 20 ° C. lower than its melting point. , Elastic modulus E '(Kgf / cm ² ) is 1 × 10 ⁶ <E'
A polyester resin satisfying <1 × 10 ⁹ is extruded in a temperature range 10 to 20 ° C. higher than the melting point to form a preform, and then blown at a resin temperature 5 to 20 ° C. lower than the melting point. .

[0007]

[Chemical 4]

(In the formula, n represents an integer of 0 to 10.)

[0009]

[Chemical 5]

(In the formula, R ¹ and R ² independently represent an alkylene group, p is 3 or 4, and q and r independently represent an integer of 0 or 1 or more.)

[0011]

[Chemical 6]

(In the formula, R ³ represents an alkylene group, t is 2 or 3, and m represents an integer of 0 or 1 or more.) Next, the present invention will be described in detail.

The aliphatic dicarboxylic acid used in the present invention is represented by the above formula [I]. When n in the above formula [I] exceeds 10, the physical properties of the obtained molded article deteriorate.

As such an aliphatic dicarboxylic acid,
Oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid and the like are preferably used.

Examples of the aliphatic diol used in the present invention include glycol and polyalkylene oxide.

As the glycol, ethylene glycol, propylene glycol, trimethylene glycol,
1,4-butanediol, 1,5-pentanediol,
1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, cyclopentane-1,
2-diol, cyclohexane-1,2-diol, cyclohexane-1,3-diol, cyclohexane-
1,4-diol, cyclohexane-1,4-dimethanol and the like can be mentioned. As the polyalkylene oxide, polyethylene oxide, polypropylene oxide,
Examples thereof include polytetramethylene oxide and polyhexamethylene oxide, which may be used alone or in combination of two or more kinds.

When the number average molecular weight of this polyalkylene oxide is small, the ability to impart flexibility to the polyester resin produced is reduced, and when it is too large, physical properties such as thermal stability of the obtained polyester resin are reduced. , 100 to 20,000 is preferable, and 500 to 5,000 is more preferable.

The hydroxy compound used in the present invention is
It is at least one selected from the group consisting of a dihydroxy compound represented by the following formula [II] and a monohydroxy compound represented by the following formula [III].

[0019]

[Chemical 7]

[0020]

[Chemical 8]

The dihydroxy compound represented by the above formula [II] is a low molecular weight compound exhibiting liquid crystallinity, the alkylene groups R ¹ and R ² are preferably ethylene groups or propylene groups, and q and r are 0 or 1. Is preferred. The dihydroxy compound is represented by the following formula [A]: 4,4 ″
-Dihydroxy-p-terphenyl, 4,4 '"-dihydroxy-p-quarterphenyl represented by the following formula [B], 4,4"'-di (2 represented by the following formula [C] -Hydroxyethoxy) -p-quaterphenyl and the like are preferably used.

[0022]

[Chemical 9]

The transition temperature from the crystalline state to the liquid crystal state of 4,4 ″ -dihydroxy-p-terphenyl [A] is 26.
At 0 ° C., that of 4,4 ′ ″-dihydroxy-p-quaterphenyl [B] is 336 ° C.
That of (2-hydroxyethoxy) -p-quaterphenyl [C] is 403 ° C. Here, the liquid crystal state means a state in which the compound is in a molten state and the molecules maintain the alignment state. Such a liquid crystalline molecule generally has high crystallinity and, as described above, has a high transition point from a crystalline state to a liquid crystal state. Therefore, when these dihydroxy compounds [II] are incorporated into a polymer chain, Polymers show unique properties. That is, even if the compounding amount of the dihydroxy compound [II] is small, a strong and heat-resistant physical crosslink is formed. As a result, it is presumed that a thermoplastic elastomer having high heat resistance can be obtained without impairing the flexibility derived from the soft segment. Such a dihydroxy compound may be used alone or 2
You may use together more than one kind.

The monohydroxy compound represented by the above formula [III] is a rigid low molecular compound having a paraphenylene skeleton, and the melting point of these compounds is extremely high, reflecting the characteristic molecular structure. Further, the paraphenylene skeleton is known to be effective as a mesogen for low-molecular liquid crystal compounds, and it has a strong cohesive force not only in the solid state but also in the high temperature state (molten state). Indicates. Therefore, the above monohydroxy compound [II
When [I] is incorporated into the polymer terminal, it brings about very strong physical crosslinks with high heat resistance and produces a thermoplastic elastomer having excellent heat resistance.

In the above formula [III], R ³ is preferably an ethylene group or a propylene group, and n is preferably 0 or 1. Examples of the monohydroxy compound include 4-hydroxy-p-terphenyl, 4-hydroxy-p-quaterphenyl, 4- (2-hydroxyethoxy) -p-terphenyl and 4- (2-hydroxyethoxy) -p-. Quarter phenyl etc. can be mentioned. Such monohydroxy compounds [II] may be used alone or in combination.

The polyester resin comprising the dihydroxy compound [II], the aliphatic diol, and the dicarboxylic acid has low heat resistance when the content of the dihydroxy compound [II] is low, and the elastic modulus is high when the content is high. Therefore, the flexibility is lowered and it becomes unsuitable as a thermoplastic elastomer. Therefore, the content of the dihydroxy compound [II] is calculated when the constitutional unit of the polyester resin is counted as one monomer (for example, a polyester having a degree of polymerization of 10 is counted as 10 monomers, and a polyalkylene oxide or a diol other than aromatic is used as the diol). In the case of using a polysilicone (which will be described later, the constitutional unit is counted as one monomer), it is 0.1 in all the monomers constituting the polyester resin.
To 30 mol% is preferable, and 1.0 to 10 is more preferable.
Mol%.

The polyester resin comprising the above monohydroxy compound [III], the above aliphatic diol and the above dicarboxylic acid has a low heat resistance when the content of the monohydroxy compound [III] is low, and a polyester resin when the content of the monohydroxy compound [III] is high. The molecular weight of does not increase sufficiently, and the physical properties of the obtained molded product are poor. Therefore, the content of the monohydroxy compound [III] is preferably 0.1 to 20 mol% in all the monomers constituting the polyester resin.

A polyester resin comprising the dihydroxy compound [II], the monohydroxy compound [III], the aliphatic diol, and the dicarboxylic acid is
When the total content of the dihydroxy compound [II] and the monohydroxy compound [III] decreases, the heat resistance decreases, and when the total content increases, the flexibility decreases and a sufficient increase in molecular weight cannot be obtained. Therefore, the total content of the dihydroxy compound [II] and the monohydroxy compound [III] is
0.1 to 3 in all monomers constituting the polyester resin
0 mol% is preferable.

In this case, the dihydroxy compound [II]
The content ratio of the monohydroxy compound [III] and the content of the monohydroxy compound [III] is preferably in a range satisfying 0 <[III] / ([II] + [III]) <2/3.

The branching agent used in the present invention has a polyol having 3 to 6 hydroxyl groups, a polycarboxylic acid having 3 to 4 carboxyl groups, and a hydroxyl group and a carboxyl group, the number of which is 3 to 6. It is at least one selected from the group consisting of certain oxyacids.

As the polyol, glycerin, trimethylolpropane, pentaerythritol, 1,2,6-
Hexanetriol, sorbitol, 1,1,4,4-
Tetrakis hydroxymethyl cyclohexane, tris (2-hydroxyethyl) isocyanurate, dipentaerythritol and the like can be mentioned.

As the polycarboxylic acid, hemimellitic acid, trimellitic acid, trimellitic acid, pyromellitic acid,
1,1,2,2-ethanetetracarboxylic acid, 1,1,2
-Ethane tricarboxylic acid, 1,3,5-pentane tricarboxylic acid, 1,2,3,4-cyclopentane tetracarboxylic acid and the like. These polycarboxylic acids may be used as they are, but it is preferable to use them in the form of a lower alkyl ester.

Examples of oxyacids are citric acid, tartaric acid, and 3
-Hydroxyglutaric acid, mucus acid, trihydroxyglutaric acid, 4-β-hydroxyethylphthalic acid and the like can be mentioned.

These branching agents are not limited to one kind, and a plurality of kinds may be used, and the addition amount is preferably 0.6 to 2.5 equivalents per 100 mol of the aliphatic dicarboxylic acid. When the amount of the branching agent added is less than 0.6 equivalent, the polyester resin produced is insufficiently branched, and thus the produced polyester resin has a low viscosity and is not suitable for extrusion blow molding. When the amount of the branching agent added exceeds 2.5 equivalents, gelation occurs during production, so the molecular weight of the obtained polyester resin, that is, the intrinsic viscosity [η] is 2.0 or more, and the viscosity of the polyester resin is too high. Therefore, it is not suitable for extrusion blow molding. Further, the obtained polyester resin has reduced heat resistance, tensile speed, and mechanical strength such as tensile elongation.

The composition of the polyester resin used in the present invention is as described above, but it may contain a poly-silicone having two hydroxyl groups, a lactone, or an aromatic hydroxycarboxylic acid as a constituent component.

This polysilicone has two hydroxyl groups, and a polysilicone having two hydroxyl groups at the molecular ends is preferable, and dimethylpolysiloxane, diethylpolysiloxane having two hydroxyl groups at both ends of the molecule,
Diphenyl polysiloxane etc. are mentioned. If the number average molecular weight of the polysilicone is small, the ability to impart flexibility to the polyurethane produced is reduced, and if it is large, it becomes difficult to produce polyester.
000 or less is preferable, and more preferably 500 to 5,0.
00.

The lactone opens the ring and reacts with an acid and a hydroxyl group to add an aliphatic chain, thereby imparting flexibility to the polyester resin. The lactone is preferably a lactone having 4 or more carbon atoms in the ring, more preferably a 5-membered to 8-membered ring, ε-caprolactone, δ-
Examples thereof include valerolactone and γ-butyrolactone.

The aromatic hydroxycarboxylic acid imparts rigidity and liquid crystallinity to the polyester resin. Examples of the aromatic hydroxycarboxylic acid include salicylic acid, metahydroxybenzoic acid, parahydroxybenzoic acid, 3-chloro-4-
Hydroxybenzoic acid, 3-bromo-4-hydroxybenzoic acid, 3-methoxy-4-hydroxybenzoic acid, 3-methyl-4-hydroxybenzoic acid, 3-phenyl-4-hydroxybenzoic acid, 2-hydroxy-6- Naphthoic acid,
4-hydroxy-4'-carboxybiphenyl etc. are mentioned, Preferably it is para-hydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, 4-hydroxy-4'-carboxybiphenyl etc.

Further, the polyester resin may contain an aromatic diol or aromatic dicarboxylic acid other than the dihydroxy compound as a constituent component in order to improve the mechanical properties of the polyester resin.

As the aromatic diol, hydroquinone,
Resorcin, chlorohydroquinone, bromohydroquinone, methylhydroquinone, phenylhydroquinone, methoxyhydroquinone, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl ether, 4,
4'-dihydroxydiphenyl sulfide, 4,4 '
-Dihydroxydiphenyl sulfone, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenylmethane, bisphenol A, 1,1-di (4-hydroxyphenyl) cyclohexane, 1,2-bis (4-
Examples thereof include hydroxyphenoxy) ethane, 1,4-dihydroxynaphthalene, and 2,6-dihydroxynaphthalene.

Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, metal salts of 5-sulfoisophthalic acid,
4,4'-dicarboxybiphenyl ether, 4,4 '
-Dicarboxydiphenyl sulfide, 4,4'-dicarboxydiphenyl sulfone, 3,3'-dicarboxybenzophenone, 4,4'-dicarboxybenzophenone, 1,2-bis (4-carboxyphenoxy) ethane, 1,4 -Dicarboxynaphthalene, 2,6-dicarboxynaphthalene and the like.

The polyester resin comprising the above constituents can be produced by any of the known polycondensation methods listed below.

A method in which a dicarboxylic acid and a diol component (including an aliphatic diol, a dihydroxy compound, a monohydroxy compound, etc.) are directly reacted, and a lower ester of dicarboxylic acid is reacted with a diol component by transesterification. A method of reacting a dicarboxylic acid halide with a diol component in a suitable solvent such as pyridine, a method of reacting a metal alcoholate of the diol component with a dicarboxylic acid halide, an acetyl component of the diol component and a dicarboxylic acid A method of reacting using transesterification.

The type and addition method of the above branching agent usually differs depending on the polycondensation method used.

When the method (1) is used, it is preferable to add the polyol, polycarboxylic acid or oxyacid to the reaction medium by the end of the reaction. When the method (1) is used, it is preferable to add the lower ester of polycarboxylic acid or polyol to the reaction medium before the end of the transesterification reaction. When the method (1) is used, it is preferable to add a halide of a polycarboxylic acid or a polyol to the solvent. When the method (1) is used, it is preferable to react the polyol with a metal alcoholate or react it with a polycarboxylic acid as a halide. When the method (1) is used, it is preferable to add the acetylated product of the polyol or the polycarboxylic acid by the end of the transesterification reaction.

In the polycondensation, a catalyst generally used in producing a polyester resin may be used. As this catalyst, lithium, sodium, potassium, cesium, magnesium, calcium, barium,
Metals such as strontium, zinc, aluminum, titanium, cobalt, germanium, tin, lead, antimony, arsenic, cerium, boron, cadmium and manganese, organic metal compounds thereof, organic acid salts, metal alkoxides, metal oxides and the like. .

Particularly preferred catalysts are calcium acetate, diacyl stannous tin, tetraacyl stannic tin, dibutyltin oxide, dibutyltin dilaurate, dimethyltin malate,
Tin dioctanoate, tin tetraacetate, triisobutyl aluminum, tetrabutyl titanate, germanium dioxide, and antimony trioxide. Two or more kinds of these catalysts may be used in combination.

Further, in order to efficiently distill off water, alcohol, glycol and the like, which are by-products of the polymerization, to obtain a high molecular weight polymer, the reaction system is set to 1 mmHg at the latter stage of the polymerization.
It is preferable to reduce the pressure below. The reaction temperature is generally 15
It is 0 to 350 ° C.

The following additives may be added during or after the production of the polyester resin of the present invention as long as the practicality thereof is not lost.

(I) Heat stabilizer: triphenylphosphite, trilaurylphosphite, trisnonylphenylphosphite, 2-tert-butyl-α- (3-te
rt-butyl-4-hydroxyphenyl) -p-cumenylbis (p-nonylphenyl) phosphite, etc., (ii) flame retardant: tris- (2,3-dichloropropyl) phosphate, pentabromophenylallyl ether, etc. ) Ultraviolet absorber: p-tert-butylphenyl salicylate, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2′-carboxybenzophenone, 2,4,5-trihydroxybutyrophenone, etc. (iv) Antioxidant: butylhydroxyanisole, butylhydroxytoluene, distearylthiodipropionate, dilaurylthiodipropionate, hindered phenolic antioxidant, etc. (v) Antistatic agent: N, N-bis (hydroxy) Ethyl) alkylamine, alkylallylsulfo (Vi) inorganic substances: barium sulfate, alumina, silicon oxide, etc. (vii) higher fatty acid salts: sodium stearate, barium stearate, sodium palmitate, etc. (viii) organic compound: benzyl alcohol , Benzophenone, etc., (ix) Crystallization accelerator: highly crystallized polyethylene terephthalate, polytrans-cyclohexanedimethanol terephthalate, etc.

Next, the extrusion blow molding method will be described.

In the extrusion blow molding method, a resin is melted in a cylinder, and the molten resin is extruded from a nozzle to form a preformed body (parison), and a parison is put in a mold and at the same time. , A blowing step of blowing air into the parison to form a predetermined hollow body.

In the parison extrusion step, the melt flow index χ ((g / 10 min), hereinafter referred to as MFI) of the polyester resin when it is higher than the melting point of the polyester resin by 10 to 20 ° C. is 0.1 <χ <2. It is preferably within the range of 5.

When the MFI is 2.5 or more, the viscosity of the parison resin at the time of forming the parison is too low, so that the drawdown of the parison, that is, the descending speed of the parison tip is fast, and parison molding is impossible. When the MFI is 0.1 or less, the viscosity of the parison resin is too high at the time of forming the parison in extrusion blow molding, so that the parison resin is difficult to be extruded from the nozzle, and molding of the parison is difficult.
Even if the parison is formed, the resulting surface of the parison is non-uniform, dull, and the like, which causes problems on the resulting surface of the parison.

Next, the reason for using MFI at a temperature 10 to 20 ° C. higher than the melting point will be described.

That is, in actual molding, if the molding is carried out at a temperature higher than the melting point by 25 ° C. or more, the polyester resin is apt to undergo thermal decomposition, and if the molding is carried out at a temperature higher than the melting point by 5 ° C. or less This is because the insoluble portion remains in a part of the above and the surface property of the molded product is likely to be non-uniform.

Therefore, the temperature higher than the melting point of the polyester resin by 10 to 20 ° C. means the temperature range in which the polyester does not undergo thermal decomposition and melts uniformly. Generally, the melting point of the obtained polyester resin is 1
Since the temperature is 70 to 230 ° C, the resin temperature during the extrusion step is 180 to 250 ° C.

In the blowing step, when the temperature is 5 to 20 ° C. lower than the melting point of the polyester resin, the elastic modulus E '(Kgf
/ Cm ² ) is preferably in the range of 1 × 10 ⁶ <E ′ <1 × 10 ⁹ , and more preferably 5 × 10 ⁶ <E ′.
<1 × 10 ⁹ .

The elastic modulus E ′ is 1 × 10 ⁹ (Kgf / c
In the case of m ² ) or more, since the parison resin is too hard during the blowing step of the extrusion blow molding method, the parison does not swell even when blown, and thus the parison cannot be blown. When the elastic modulus E ′ is 1 × 10 ⁶ (Kgf / cm ² ) or less, the parison resin is too soft or the parison resin is in a semi-molten state at the time of the blowing step of the extrusion blow molding method. The blow of the parison is impossible, and it is impossible.

Next, the blowing condition is set to a temperature 5 to 20 ° C. lower than the melting point, and the elastic modulus E ′ is 1 × 10 ⁶ <E ′ <1 × 10 ^9.
The reason for limiting to within the range will be described.

When the parison resin is blown at a temperature 25 ° C. lower than the melting point in the blowing step, the parison resin has an elastic modulus E ′ of 1 × 10 ⁹ (Kgf / cm ² ) or more, which is too hard and the parison is It doesn't swell when blown, so it is impossible to blow a parison. When the parison resin temperature is blown at a temperature 5 ° C. lower than the melting point and the elastic modulus E ′ is 1 × 10 ⁶ (Kgf / cm ² ) or less at the same time, the parison resin is too soft during the blowing step.
Alternatively, since the parison resin is in a semi-molten state, there is a hole in the parison and it is impossible to blow the parison.

Therefore, the temperature lower than the melting point of the polyester resin by 5 to 20 ° C. means the temperature range in which the parison resin can be blown. In general, the melting point of the obtained polyester resin is 170 to 230 ° C, so the resin temperature during the blowing step is 150 to 225 ° C.

[0063]

EXAMPLES The present invention will be described below based on examples.

Example 1 87.1 g (0.5 mo) of methyl adipate was placed in a glass flask having an internal volume of 1 L equipped with a stirrer, a thermometer, a gas blowing port, and a distillation port.
l), 74.4 g of ethylene glycol (1.2 mo
1), and 17.8 g of 4,4 ′ ″-dihydroxy-p-quarterphenyl (hereinafter referred to as DHQ), methyl trimellitate (hereinafter referred to as TMT) 4 as a branching agent
70 mg (0.8 equivalent per 100 mol of dicarboxylic acid), 172 mg of calcium acetate and 36 mg of germanium oxide as a catalyst were added. After replacing the flask with nitrogen, the temperature of the flask was raised to 180 ° C. The temperature was kept for 2 hours to carry out the ester conversion reaction. During this reaction,
Methanol was distilled from the reaction mixture. Then, the flask is heated to 300 ° C., stirred for 30 minutes, and then 1 mm
The pressure was reduced to Hg or less, and the polycondensation reaction was performed for 15 minutes in this state. With the reaction, ethylene glycol was distilled out, and an extremely viscous liquid was produced in the flask.

Next, the intrinsic viscosity and melting point of the obtained resin were measured. The intrinsic viscosity [η] was measured by the ortho-chlorophenol method (30 ° C.), and the melting point was measured by the DSC method.

Further, using an extrusion blow molding machine, the nozzle set temperature was set to 210 ° C., and an extrusion blow molding test of the obtained resin was conducted. “Parison tip descent rate”, “MFI of parison resin” and “parison appearance” are important elements of the extrusion blow molding parison forming process.
Where the parison tip descent rate (unit (g / sec))
Measured the descent rate of the parison tip when a parison having a weight of 200 g was formed at the nozzle tip, and at the same time observed the appearance of the parison. Furthermore, the MFI (unit (g / 10 minutes)) of the parison resin was measured by a melt flow index tester.

(Examples 2 to 6) The same as Example 1 except that the amount of the branching agent TMT used and the nozzle temperature of the extrusion blow molding machine were changed as shown in Tables 1 and 2. The resin was obtained, and the physical properties of this resin were measured in the same manner as in Example 1.

Comparative Examples 1 to 18 Same as Example 1 except that the amount of branching agent TMT used and the nozzle temperature of the extrusion blow molding machine were changed as shown in Tables 1 and 2. The resin was obtained, and the physical properties of this resin were measured in the same manner as in Example 1.

TM of Examples 1-6 and Comparative Examples 1-18
Table 1 shows the T content, intrinsic viscosity and melting point, and Table 2 shows the results of the extrusion blow molding test in the parison extrusion step.

[0070]

[Table 1]

In Table 1, 1) TMT is 100% of dicarboxylic acid.
It is the number of equivalents per mol, and 2) the melting point is based on the DSC method.

[0072]

[Table 2]

In Table 2, 3) MFI is ASTM D1238
The measurement condition is a load of 2.16 Kg, 4)
The parison tip descent rate is measured under a parison weight of 200.
It is g.

From the results of Tables 1 and 2, the following can be seen.

When the branching agent TMT is not added (Comparative Example 1)
4), the MFI of the obtained resin tends to be 2.5 or more, the drawdown of the parison is severe, and the formation of the parison is impossible.

When the amount of the branching agent TMT added was small (Comparative Examples 5 to 8), the MFIs of the obtained resins were likely to be 2.5 or more, and the drawdown of the parison was severe. Even if the resin temperature of the parison is 5 ° C. higher than the melting point, the MFI becomes less than 2.5, but the parison resin is partially insoluble and the surface is not glossy.

Even when the addition amount of the branching agent TMT is appropriate (Comparative Examples 9 to 14), when the nozzle temperature of the extrusion blow molding machine is 5 ° C. higher than the melting point of the parison resin, the MFI of the obtained resin is It becomes 0.1 or less and extrusion of the parison is impossible.

When the nozzle temperature of the extrusion blow molding machine is 25 ° C. higher than the melting point of the parison resin, the drawdown is severe.

The branching agent TMT is added in an appropriate amount, and the nozzle temperature of the extrusion blow molding machine is 10 to 10 ° C above the melting point of the parison resin.
At 20 ° C. higher temperature (Examples 1 to 6), no abnormalities were observed in the extrusion and appearance of the parison.

When the amount of the branching agent TMT added is too large (Comparative Examples 15 to 18), the obtained resin gels, so that the MFI of the parison resin becomes 0.1 or less and extrusion of the parison is unsuccessful. It is possible.

Example 7 87.1 g (0.5 mo) of methyl adipate was placed in a glass flask having an internal volume of 1 L equipped with a stirrer, a thermometer, a gas blowing port, and a distillation port.
l), 74.4 g of ethylene glycol (1.2 mo
1), and 17.8 g of 4,4 ′ ″-dihydroxy-p-quarterphenyl (hereinafter referred to as DHQ), methyl trimellitate as a branching agent (hereinafter referred to as TMT) 1
175 mg (2.0 equivalents per 100 mol of dicarboxylic acid), 172 mg of calcium acetate and 36 mg of germanium oxide as catalysts were added. After replacing the flask with nitrogen, the temperature of the flask was raised to 180 ° C. The temperature was kept for 2 hours to carry out the ester conversion reaction. During this reaction,
Methanol was distilled from the reaction mixture. Then, the flask is heated to 300 ° C., stirred for 30 minutes, and then 1 mm
The pressure was reduced to Hg or less, and the polycondensation reaction was performed for 15 minutes in this state. With the reaction, ethylene glycol was distilled out, and an extremely viscous liquid was produced in the flask.

Next, the intrinsic viscosity and melting point of the obtained resin were measured. The intrinsic viscosity [η] was measured by the ortho-chlorophenol method (30 ° C.), and the melting point was measured by the DSC method.

Further, using an extrusion blow molding machine, the nozzle temperature was set to 210 ° C., and an extrusion blow molding test of the obtained resin was conducted. “Viscoelasticity E ′ of parison resin” and “blow state of parison” are important elements in the parison forming step of extrusion blow molding. Here, the viscoelasticity E ′ of the parison resin means that the obtained resin has a mold temperature of 70
℃, nozzle temperature of 210 ℃ extruded on the sheet,
Sheet-shaped resin was punched out and Shimadzu Autograph (AG-5000B) was used in accordance with JIS K6301.
It was measured. Further, the appearance of the blow-molded product was observed to observe the blown state of the parison.

(Examples 8 to 10) A resin was obtained in the same manner as in Example 7 except that the nozzle temperature of the extrusion blow molding machine was changed as shown in Table 3. About this resin, Example 7 was obtained. Each physical property was measured by the same method as.

Comparative Examples 19 to 20 Resins were obtained in the same manner as in Example 7 except that the nozzle temperature of the extrusion blow molding machine was changed as shown in Table 3. Each physical property was measured by the same method as.

Table 3 shows the physical properties of Examples 8 to 10 and Comparative Examples 19 to 20 during the blowing step.

[0087]

[Table 3]

In Table 3, 5) TMT was 100% of dicarboxylic acid.
It is the number of equivalents per mol, and 6) the melting point is based on the DSC method.

From the results shown in Table 3, the following can be seen.

When the parison resin was blown at a temperature 25 ° C. lower than the melting point (Comparative Example 19), the elastic modulus E ′ of the parison resin was as high as 2 × 10 ⁹ (Kgf / cm ² ), that is, the parison resin. Became hard and the parison did not swell, and it was impossible to blow the parison.

When the parison resin is blown at a temperature 20 ° C. lower than the melting point (Example 7), the parison can be blown, but it takes time to cool the parison resin and the high cycle property is deteriorated. To do.

The parison resin temperature is 5 to 15 ° C. higher than the melting point.
When blown at a low temperature (Examples 8 to 10), the parison can be blown and no abnormality is found in the molded product.

When the parison resin was blown at the temperature of the melting point (Comparative Example 20), the parison resin partially melted and was very flexible, so that the parison was perforated and the parison could not be blown.

[0094]

The extrusion blow-molded product of a highly viscous polyester resin having properties as a thermoplastic elastomer and having an appropriate amount of a branching agent can be manufactured by controlling the resin temperature and the MFI range of the resin during the parison extrusion process. By determining the resin temperature and the range of resin viscoelasticity E ′ during the blowing process,
It is possible.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Daishiro Kishimoto 2-24-23 Mishimaoka, Ibaraki City, Osaka Sunhits Mishimaoka 306

Claims (1)

[Claims] 1. An aliphatic dicarboxylic acid represented by the following general formula [I], an aliphatic diol, a dihydroxy compound represented by the following general formula [II], and a monohydric compound represented by the following general formula [III]. At least one hydroxy compound selected from the group consisting of hydroxy compounds, a polyol having 3 to 6 hydroxyl groups, a polycarboxylic acid having 3 to 4 carboxyl groups, and a hydroxyl group and a carboxyl group, At least one branching agent selected from the group consisting of oxy acids having a group number of 3 to 6 is used as a constituent component, and the branching agent is an aliphatic dicarboxylic acid 10
In a polyester resin containing 0.6 to 2.5 equivalents per 0 mol, when the temperature is 10 to 20 ° C. higher than the melting point, the melt flow index χ (g / 10 minutes) is 0.1 <χ <
In the range of 2.5 and 5-20 ° C above its melting point
When the temperature is low, the elastic modulus E '(Kgf / cm ² ) is
A polyester resin satisfying 1 × 10 ⁶ <E ′ <1 × 10 ⁹ is extruded in a temperature range 10 to 20 ° C. higher than the melting point,
A method for producing an extrusion blow-molded article of a polyester resin, comprising forming a preform and then blowing at a resin temperature 5 to 20 ° C. lower than the melting point. [Chemical 1] (In the formula, n represents an integer of 0 to 10.) (In the formula, R ¹ and R ² independently represent an alkylene group,
p is 3 or 4, q and r each independently represent 0 or an integer of 1 or more. ) [Chemical 3] (In the formula, R ³ represents an alkylene group, t is 2 or 3, and m is 0 or an integer of 1 or more.)