JPH06211973A - Polyester resin for extrusion blow molding and hollow container made therefrom - Google Patents

Abstract

PURPOSE:To obtain a polyester resin which is transparent and impact-resistant, can be molded by direct blow molding, and can substitute for a polyvinyl choride resin. CONSTITUTION:This polyester resin for extrusion blow molding is produced by reacting a dicarboxylic acid component mainly comprising terephthalic acid with a glycol component contg. 5-80mol% compd. of the formula (wherein (m) and (n) are each an integer of 1-5). A hollow container is made from this resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin having transparency and heat resistance and capable of extrusion blow molding, and a hollow container using the same.

[0002]

2. Description of the Related Art Polyvinyl chloride is widely used as a material for packaging materials because it has excellent properties such as moldability and impact resistance. However, in recent years, there is a tendency that there is a problem that polyvinyl chloride containing chlorine atoms may have an adverse effect on the global environment, such as the generation of hydrogen chloride due to incineration. , Is on the decline.

At present, in addition to polyvinyl chloride, polyethylene terephthalate is mainly used as a material for highly transparent containers. However, the molding method is different for both, and in the case of polyvinyl chloride, container molding is performed by extrusion blow molding like polyethylene etc., but in the case of polyethylene terephthalate, the preform is once molded by injection molding and then stretched It is usual to perform container molding by injection biaxial stretch blow molding for blowing. When an extrusion blow molding of polyethylene terephthalate is attempted, there is a problem that a drawdown is large and crystallization occurs and it is difficult to obtain a uniform transparent container. Therefore, if a resin capable of direct blow molding, which has transparency and impact resistance, can be obtained instead of polyvinyl chloride, the capital investment of a molding machine can be dispensed with, and its significance is significant.

[0004]

As a result of intensive studies to solve the above problems, the present inventors have found a specific polyester resin suitable for extrusion blow molding and having transparency and impact resistance. The invention was completed. That is, the present invention is characterized in that the main component of the dicarboxylic acid component constituting the polyester is terephthalic acid, 5 to 80 mol% of the glycol component is a compound represented by the following formula (1) extrusion blow molding The present invention provides a polyester resin for use, and a hollow container using the polyester resin.

[0005]

[Chemical 2]

(In the formula, m and n each represent an integer of 1 to 5.) The main component of the dicarboxylic acid component constituting the polyester resin of the present invention is a terephthalic acid unit,
Besides, other dicarboxylic acid components may be contained within the range of less than 20 mol%. Other dicarboxylic acid components include isophthalic acid, 1,5-, 1,6-, 1,7-, 2,6-naphthalenedicarboxylic acid, phthalic acid, cyclohexanedicarboxylic acid, dibromoisophthalic acid, sodium -Sulfoisophthalic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenylketonedicarboxylic acid, diphenoxyethanedicarboxylic acid, aromatic dicarboxylic acids such as phenylenedioxydiacetic acid, adipic acid, sebacic acid, succinic acid, Examples thereof include aliphatic dicarboxylic acids such as glutaric acid, piperic acid, suberic acid, azelaic acid, undecadioic acid, and dodecadioic acid, or a mixture of two or more thereof.

The glycol component constituting the copolymerized polyester resin of the present invention is such that 5 to 80 mol% of the glycol component is composed of the compound represented by the above formula (1). Examples of the compound represented by the formula (1) include 1,4-bis (2-hydroxyethoxy) benzene and 1,4-bis (2-hydroxyethoxyethoxy) benzene.

In the formula (1), m and n are each 1 to
The integer of 5 is shown and the thing of 1-3 is especially preferable. m, n
Is more than 5, the polyester resin obtained by using it has a low glass transition temperature (Tg), which is not preferable because mechanical properties such as elastic modulus and tensile strength are deteriorated.

As the glycol component other than the compound of the above formula (1) which constitutes the copolyester resin of the present invention,
Aliphatic glycols such as ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, propylene glycol, neopentyl glycol, diethylene glycol and polyethylene glycol, and fats such as cyclohexanedimethanol Aromatic glycols such as cyclic glycols, o, m, p-xylylene glycols, ethylene oxide of 2,2-bis (4-hydroxyphenyl) propane, and propylene oxide adducts may be used alone or in admixture of two or more. . Of these, ethylene glycol is preferably used, and glycols other than ethylene glycol account for all glycol components of the copolyester resin.
It is preferably used within the range of less than 20 mol%.

The copolymerized polyester resin of the present invention contains the compound represented by the above formula (1) in an amount of 5 to 80 in its glycol component.
It is the one containing a mol%, preferably 25 to 70 mol%.
If the amount of the compound represented by the formula (1) in the glycol component is less than 5 mol%, the modifying effect is small. That is, the drawdown during molding is large, it is difficult to suppress crystallization, extrusion blow molding is difficult, and the impact strength is small. When the amount of the compound represented by the formula (1) introduced is more than 80 mol%, the glass transition temperature becomes low, the heat resistance becomes poor, and a uniform wall thickness cannot be obtained, which is not preferable.

Further, hydroxycarboxylic acids such as glycolic acid, hydroxybenzoic acid and hydroxynaphthoic acid,
You may copolymerize diphenols, such as hydroquinone, resorcinol, dihydroxydiphenyl, and dihydroxydiphenyl ether. As a method for synthesizing a polyester using these monomers, any method may be used as long as it is a general polyester synthesizing method such as a direct polycondensation method or a transesterification method.

The intrinsic viscosity (measured at 25 ° C. using a mixed solvent of phenol / tetrachloroethane (weight ratio: 6/4)) of the polyester resin of the present invention is preferably 0.5 dl / g or more. When it is less than 0.5 dl / g, the mechanical properties of the obtained container are deteriorated, which is not preferable.

The polyester resin of the present invention has a lower softening point and a lower crystallinity than polyethylene terephthalate, facilitates extrusion blow molding, and has impact resistance. Further, various additives such as a colorant, an antioxidant, an ultraviolet absorber, an antistatic agent, a flame retardant and the like can be blended with the polyester resin of the present invention as required.

The hollow container of the present invention can be manufactured by the usual extrusion blow molding method using the polyester resin of the present invention. Such a hollow container is transparent, heat resistant,
Since it has excellent mechanical strength, it is useful as an alternative container to a polyvinyl chloride container.

[0015]

The present invention is described in detail below with reference to examples, but these examples do not limit the present invention in any way. The intrinsic viscosity of the polymer was measured at 25 ° C. using a mixed solvent of phenol / tetrachloroethane (weight ratio 6/4). The glass transition temperature (Tg) was measured using a dynamic viscoelasticity measuring device RSA-2 manufactured by Rheometrics. The glass transition temperature was defined as the peak top of the loss elastic modulus when strain was applied at a cycle of 1 Hz. According to JIS-K7110, the impact resistance test was performed by notching an Izod impact test with a notch using a 2.5 mm-width injection-molded test piece for evaluation.

Example 1 100 mol (19.42 kg) of dimethyl terephthalate was placed in a reactor equipped with a stirring blade, a nitrogen inlet and a pressure reducing port, and 1,4-bis (2
20 mol (3.96 kg) of -hydroxyethoxy) benzene, 180 mol (11.17 kg) of ethylene glycol, and 10 g each of zinc acetate and germanium dioxide as catalysts were charged. Heat to 180 ℃ under nitrogen stream to conduct transesterification reaction,
The methanol was distilled off. After 4 hours, almost the theoretical amount of methanol was distilled off, so that the temperature was raised to 270 ° C. and the pressure was gradually reduced to polymerize at 0.1 to 0.3 Torr for 5 hours. As a result of ¹ H-NMR analysis of the obtained polymer, 100 mol% of the dicarboxylic acid component constituting the polyester was a terephthalic acid unit, and 19 mol% of the glycol component was 1,4-bis (2-hydroxyethoxy). 81 mol% of benzene was an ethylene glycol unit. The physical properties of the obtained polymer were measured and evaluated using an injection molded product. The results are shown in Table 1.

After crushing the obtained polymer with a crusher,
It was dried at 80 ° C for 1 day. After that, extrusion blow molding is performed, the capacity is 600 ml, the width of the body is about 96 mm, the depth of the body is about 52 m.
A flat container having m, a height of 235 mm and a mouth diameter of 27 mm was formed.
The extrusion blow molding was performed using a 70-mmφ extrusion screw using a Bu-7054M-P molding machine manufactured by Tahara Seisakusho KK. With respect to the obtained container, it can be molded by the following method, the uniformity of the wall thickness of the container,
The transparency and impact resistance were evaluated. The results are shown in Table 1 together with the cylinder temperature during molding.

<Moldability> Was it molded into a bottle shape?
It was evaluated whether or not. <Uniformity of thickness of container> The thickness of the body of the container was measured at several places, and the degree of variation from the average value was evaluated. ○ ・ ・ ・ ・ Width of variation is less than 20% of average value △ ・ ・ ・ ・ Width of variation is 20 to 50% of average value × ・ ・ ・ ・ ・ ・ Width of variation is 50% of average value % Or more <Transparency> It was evaluated by visual observation in three grades of ◯, Δ, and ×. ○ ・ ・ ・ ・ Transparency equivalent to PET △ ・ ・ ・ ・ ・ ・ Slightly hazy × ・ ・ ・ ・ Opaque <Impact resistance> Add 500 ml of ion-exchanged water to a 600 ml container and cap at 23 ° C, 65% The sample was left for 1 day under the condition of RH, and then dropped from a height of 1 m onto the concrete surface, and the degree of cracking of the container was evaluated in three levels. O: No cracks were generated at all. △ ・ ・ ・ ・ Although a slight crack was generated, the water inside did not leak. × ・ ・ ・ ・ A crack was generated and the water inside was scattered.

Example 2 1,4-bis (2-hydroxyethoxy) benzene and ethylene glycol were charged at 30 mol (5.94 kg), respectively.
A polymer was synthesized in the same manner as in Example 1 except that the amount was 170 mol (10.55 kg), and the container was molded by direct blow molding. The obtained polymer was analyzed by ¹ H-NMR, and as a result, ¹ % of the dicarboxylic acid component constituting the polyester
00 mol% is terephthalic acid unit and 27 mol% of glycol component is 1,4-bis (2-hydroxyethoxy)
The benzene unit and 73 mol% were ethylene glycol units. Physical properties of the obtained resin were evaluated in the same manner as in Example 1, and the container obtained by performing bottle molding was evaluated for moldability, uniformity of wall thickness of the container, transparency, and impact resistance in the same manner as in Example 1. evaluated. The results are shown in Table 1 together with the cylinder temperature during molding.

Example 3 1,4-bis (2-hydroxyethoxy) benzene and ethylene glycol were charged at 50 mol (9.90 kg) each,
A polymer was synthesized in the same manner as in Example 1 except that the amount was changed to 150 mol (9.31 kg), and the container was molded by direct blow molding. The obtained polymer was analyzed by ¹ H-NMR, and as a result, ¹ % of the dicarboxylic acid component constituting the polyester
00 mol% is terephthalic acid unit and 46 mol% of glycol component is 1,4-bis (2-hydroxyethoxy)
The benzene unit was 54 mol% ethylene glycol unit. Physical properties of the obtained resin were evaluated in the same manner as in Example 1, and the container obtained by performing bottle molding was evaluated for moldability, uniformity of wall thickness of the container, transparency, and impact resistance in the same manner as in Example 1. evaluated. The results are shown in Table 1 together with the cylinder temperature during molding.

Example 4 1,4-bis (2-hydroxyethoxy) benzene and ethylene glycol were charged at 70 mol (13.86 kg) each,
A polymer was synthesized in the same manner as in Example 1 except that the amount was 130 mol (8.06 kg), and the container was molded by direct blow molding. The obtained polymer was analyzed by ¹ H-NMR, and as a result, ¹ % of the dicarboxylic acid component constituting the polyester
00 mol% is terephthalic acid unit, 64 mol% of glycol component is 1,4-bis (2-hydroxyethoxy)
The benzene unit and 36 mol% were ethylene glycol units. Physical properties of the obtained resin were evaluated in the same manner as in Example 1, and the container obtained by performing bottle molding was evaluated for moldability, uniformity of wall thickness of the container, transparency, and impact resistance in the same manner as in Example 1. evaluated. The results are shown in Table 1 together with the cylinder temperature during molding.

Comparative Example 1 Polyethylene terephthalate was synthesized from dimethyl terephthalate and ethylene glycol alone, and a container was formed by direct blow molding as in Example 1. Physical properties of the obtained resin were evaluated in the same manner as in Example 1, and the container obtained by performing bottle molding was evaluated for moldability, uniformity of wall thickness of the container, transparency, and impact resistance in the same manner as in Example 1. evaluated. The results are shown in Table 1 along with the cylinder temperature during molding.
Shown in.

Comparative Example 2 1,4-bis (2-hydroxyethoxy) benzene and ethylene glycol were charged at 3 mol (0.59 kg), respectively.
A polymer was synthesized in the same manner as in Example 1 except that the amount was 197 mol (12.23 kg), and the container was molded by direct blow molding. The obtained polymer was analyzed by ¹ H-NMR, and as a result, ¹ % of the dicarboxylic acid component constituting the polyester
00 mol% is terephthalic acid unit and 3 mol% of glycol component is 1,4-bis (2-hydroxyethoxy)
The benzene unit and 97 mol% were ethylene glycol units. Physical properties of the obtained resin were evaluated in the same manner as in Example 1, and the container obtained by performing bottle molding was evaluated for moldability, uniformity of wall thickness of the container, transparency, and impact resistance in the same manner as in Example 1. evaluated. The results are shown in Table 1 together with the cylinder temperature during molding.

Comparative Example 3 1,4-bis (2-hydroxyethoxy) benzene and ethylene glycol were charged at 85 mol (16.83 kg) each,
The polymer was synthesized in the same manner as in Example 1 except that the amount was 115 mol (7.13 kg), and the container was molded by direct blow molding. The obtained polymer was analyzed by ¹ H-NMR, and as a result, ¹ % of the dicarboxylic acid component constituting the polyester
00 mol% is terephthalic acid unit and 83 mol% of glycol component is 1,4-bis (2-hydroxyethoxy)
The benzene unit was 17 mol% ethylene glycol unit. Physical properties of the obtained resin were evaluated in the same manner as in Example 1, and the container obtained by performing bottle molding was evaluated for moldability, uniformity of wall thickness of the container, transparency, and impact resistance in the same manner as in Example 1. evaluated. The results are shown in Table 1 together with the cylinder temperature during molding.

[0025]

[Table 1]

Claims (2)

[Claims] 1. The main component of the dicarboxylic acid component constituting the polyester is terephthalic acid, and 5 of the glycol component.
A polyester resin for extrusion blow molding, wherein -80 mol% is a compound represented by the following formula (1). [Chemical 1] (In the formula, m and n each represent an integer of 1 to 5.) 2. A hollow container comprising the polyester resin according to claim 1.