JPH0762068B2 - Copolyester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a copolyester having excellent physical properties, particularly toughness, which is suitable for molding.

[Conventional technology]

Polyethylene terephthalate has been used for various purposes from the past, but it has the advantage of having a higher second-order transition point and melting point than polybutylene terephthalate, which is the same thermoplastic polyester, but its molecular chains are non-oriented. If it is sufficiently crystallized in a state, it exhibits brittleness, and an injection-molded product or an extrusion-molded product of polyethylene terephthalate that has been crystallized without being reinforced with a reinforcing material such as glass fiber cannot be put to practical use. Is the actual situation. As a method of imparting ductility to polyethylene terephthalate, for example, a method of adding a copolymer of α-olefin and a neutralized metal ion of α, β ethylenically unsaturated carboxylic acid (Japanese Patent Laid-Open Publication No. S60-12065)
52-84244), the melt viscosity of the composition is remarkably increased by this method, which causes a problem particularly in injection molding. Further, the obtained composition had a problem of color deterioration upon heating.

[Problems to be Solved by the Present Invention]

An object of the present invention is to improve the toughness by improving the drawback of polyethylene terephthalate, which is the drawback of polyethylene terephthalate, without impairing the excellent properties of polyethylene terephthalate such as high melting point and high rigidity.

[Means for solving problems]

The present inventors have begun the research to improve the toughness by improving the brittleness of polyethylene terephthalate, and the advantages of polyethylene terephthalate in comparison with polybutylene terephthalate, which is a polyester having relatively high toughness, are the advantages of high melting point and high rigidity. We set a constraint to achieve toughness while maintaining. The most important feature of the copolyester of the present invention is that it can impart toughness without substantially impairing the high melting point and high rigidity of polyethylene terephthalate.

The present inventors tried to impart ductility by copolymerizing polyethylene terephthalate with various polyalkylene glycols. As a result, some effect was observed with poly (tetramethylene oxide) glycol, but it was insufficient. However, surprisingly, when an aliphatic dicarboxylic acid having 9 or more carbon atoms or its ester-forming derivative is copolymerized with polyethylene terephthalate together with poly (tetramethylene oxide) glycol, a small amount of the copolymerization component is present. The present invention has been accomplished by finding that the tensile elongation of polyethylene terephthalate in a substantially non-oriented crystallized state greatly increases.

That is, the present invention is a copolyester substantially consisting of structural units represented by the following (I) to (IV), _{(III) OCH 2 -CH 2 -O} (IV) OCH 2 CH 2 CH 2 CH 2 -O n ( where, R represents a divalent group obtained by removing a carboxyl group from an aliphatic dicarboxylic acid or 9 carbon atoms And n is an integer of 8 to 84.) (I) is bound to (III) and / or (IV), (II) is bound to (III) and / or (IV) And substantially the total number of moles of (I) and (II) is (III)
Is equal to the total number of moles of (IV) and (II) is 0.2 to 5 moles per 100 moles of (I) in the copolyester, and (IV) is CH ₂ CH ₂ CH ₂ CH ₂ O. Unit is 3
The copolyester is characterized in that it is contained in a proportion of ˜15 mol and has an intrinsic viscosity in the range of 0.5 to 1.5.

The reason why the effect of the aliphatic dicarboxylic acid having 9 or more carbon atoms used in combination in the present invention is not clearly understood at present, but when poly (tetramethylene oxide) glycol alone is copolymerized with polyethylene terephthalate, Whereas a polymerization reaction product having a coarse phase-separated structure is obtained, when it is used in combination with an aliphatic dicarboxylic acid having 9 or more carbon atoms, it may change into a polymerization reaction product exhibiting a fine particulate dispersion structure. , Was observed by transmission electron microscope observation employing the osmium acid staining method. The inventors presume that this change in phase-separated morphology is related to the improvement of ductility property, that is, toughness.

The present invention will be described in more detail below.

In the copolyester of the present invention, the unit represented by (I) is a unit derived from terephthalic acid or its ester-forming derivative such as dimethyl terephthalate or diethyl terephthalate. The unit (I) may be replaced with a small amount of a unit based on a dicarboxylic acid component other than terephthalic acid or an ester-forming derivative thereof within a range that does not impair the effects of the present invention.

The unit represented by (II) in the copolyester of the present invention is a unit derived from an aliphatic dicarboxylic acid having 9 or more carbon atoms or an ester-forming derivative thereof, and examples thereof include azelaic acid, sebacic acid, dodecanedicarboxylic acid, and hexadecane. Examples include linear dicarboxylic acids such as dicarboxylic acids and eicosane dicarboxylic acids, and hydrogenated products of timer acids and dimer acids, and ester-forming derivatives thereof. The aliphatic dicarboxylic acids or their ester-forming derivatives may be used alone or in admixture of two or more. Particularly preferred dicarboxylic acids in the present invention are dimer acids and hydrogenated dimer acids.

The dimer acid in the present invention is produced from an unsaturated fatty acid containing 18 carbon atoms such as linoleic acid and linolenic acid, or a monohydric alcohol ester thereof, and is mainly composed of dimer acid having 36 carbon atoms. However, some monobasic acids and trimer acids are also included. In order to achieve the object of the present invention, it is preferable to use dimer acid having a low content of monobasic acid and trimer acid.

In the copolyester of the present invention, the unit (II) is preferably contained in a proportion of 0.2 mol or more and 5 mol or less with respect to 100 mol of the unit (I). Within this range, the crystallized product of the copolyester exhibits excellent ductility while maintaining high rigidity, and as a result, toughness is imparted. 0.2
If the proportion is less than the molar amount, the improvement of the toughness cannot be sufficiently achieved as in the case of using polytetramethylene glycol alone as the copolymerization component. On the other hand, if the amount exceeds 5 mols, the melting point of the crystallized product is greatly lowered and the rigidity is impaired, which is not suitable for the purpose of the present invention.

Further, in the present invention, when modified with the above-mentioned proportion of the unit (II), the brittleness of the crystallized polyethylene terephthalate, which is slightly improved by modification with only poly (tetramethylene oxide) glycol, is dramatically improved.
This effect is not achieved with aliphatic dicarboxylic acids having less than 9 carbon atoms. Further, there is no particular upper limit on the carbon number of the aliphatic dicarboxylic acid.

In the copolyester of the present invention, the unit represented by (III) is a unit derived from ethylene glycol.

The unit represented by (IV) in the copolymerized polyester of the present invention is a unit derived from poly (tetramethylene oxide) glycol. The use of poly (tetramethylene oxide) glycol as a copolymerization component is necessary in order to improve the brittleness of a substantially non-oriented crystallized product of polyethylene terephthalate, and it is necessary to improve the brittleness of the copolymerization reaction product with respect to 100 moles of terephthalic acid units. poly repeating units in (tetramethylene oxide) glycol _{CH 2 CH 2 CH 2 CH 2} -O
Is preferably contained in a proportion of 3 mol or more and 15 mol or less. If it is less than 3 mol, the brittleness of polyethylene terephthalate cannot be improved, and if it exceeds 15 mol, the rigidity of the crystallized product is lowered and the melting point is also lowered, which is contrary to the object of the present invention. .

The molecular weight of poly (tetramethylene oxide) glycol needs to be about 600 to 6000 (degree of polymerization (n): 8 to 84). Use of poly (tetramethylene oxide) glycol having a molecular weight outside the above range is not preferable because ductility is reduced. A more preferred molecular weight range is about 600
-2000 (degree of polymerization (n): 8-28).

A small amount, for example, glycerin, trimethylolpropane, pentaerythritol, hexanetriol 1,2,6, trimethylolethane, etc., is used in a range that does not impair the effects of the present invention when obtaining the copolymerized polyethylene terephthalate of the present invention. Triol or tetraol, benzenetricarboxylic acid typified by trimellitic acid, trimesic acid, pyromellitic acid, or benzenetetracarboxylic acid, or a polyvalent hydroxycarboxylic acid having 3 to 4 hydroxyl groups and carboxyl groups bonded thereto Polyfunctional monomers such as and stearic acid, aliphatic monocarboxylic acids such as oleic acid, benzoic acid, phenylacetic acid, diphenylacetic acid,
A monofunctional monomer of aromatic monocarboxylic acid such as β-naphthoic acid can also be used in combination.

The copolymerized polyester in the present invention is usually produced by a known method used in producing polyester. Generally, copolymerized polyethylene terephthalate is produced by heating a mixture of reaction components in the presence or absence of a catalyst, at atmospheric pressure or under pressure, in an inert gas atmosphere. The temperature employed to carry out these reactions is in the range of 200 ° C to 270 ° C, preferably 23
It is in the range of 0 ° C to 260 ° C. After completion of this reaction, the obtained oligomer product is polycondensed. The polycondensation reaction is carried out by the known antimony, titanium, iron, zinc, cobalt, lead,
It is carried out in the presence of a polycondensation catalyst such as a manganese or germanium catalyst at a pressure of 15 mmHg or less, preferably 1 mmHg or less at a temperature in the range of about 270 ° C to about 300 ° C.

The poly (tetramethylene oxide) glycol and the aliphatic dicarboxylic acid having 9 or more carbon atoms or their ester-forming derivatives can be added before transesterification or during the esterification reaction and during the condensation reaction. It is preferably added after the reaction or the esterification reaction, that is, in the condensation step.

The intrinsic viscosity of the polyester of the present invention is in the range of about 0.5 or more and about 1.5 or less, preferably about 0.5 or more and about 1.0 or less, when measured in a 50/50 weight mixed solvent system of phenol and tetrachloroethane at 30 ° C.

500 MHz of copolyester obtained according to the invention
^{In the 1} H-NMR spectrum, absorption of ethylene glycol bound to aliphatic dicarboxylic acid separated from absorption of ethylene glycol bound to terephthalic acid was observed, and ester of terminal hydroxyl group of poly (tetramethylene oxide) glycol was observed. Due to the newly formed absorption not observed in poly (tetramethylene oxide) glycol due to the formation of the bond, both aliphatic dicarboxylic acid and poly (tetramethylene oxide) glycol are linked to the polymer chain by an ester bond. Therefore, it can be confirmed that the polymerization reaction product is copolymerized polyethylene terephthalate.

The copolyester of the present invention has excellent toughness while maintaining the high melting point and high rigidity of polyethylene terephthalate itself, and is suitable as a material for various molded products such as films and sheets. Further, the copolyester of the present invention may contain other polymers within a range not impairing the effects of the present invention. Further, if necessary, various additives usually added to polyester, for example,
Colorants, mold release agents, antioxidants, UV stabilizers, flame retardants,
It is also possible to add a reinforcing filler and the like. The present invention will be described below with reference to examples.

Example 1 1.5 kg (9.03 mol) of terephthalic acid and 0.67 k of ethene glycol were placed in an esterification tank heated by a heating medium heated to 260 ° C.
g (10.8 mol) antimony trioxide 0.69 g, phosphorous acid 0.13 g
The content of the carboxyl groups in the slurry is 600 μeq / g.
Reduced to below. The reaction product was pressure fed into a polymerization tank, and 43 g of poly (tetramethylene oxide) glycol having a molecular weight of about 860 and dimer acid (Henkel Japan Versadim 2
88) 43 g and Irganox 1010 (trade name, manufactured by Ciba Geigy) 3.5 g were added. The jacket temperature of the polymerization tank is 280 ℃
Up to 0.3m
The pressure was reduced to mHg, and polymerization was carried out for 60 minutes in this state to obtain a copolyester, and the polymer was taken out in a strand form from a nozzle with a gear pump, cooled with water and made into pellets with a cutter. The polymer obtained had an intrinsic viscosity of 0.74 dl / g.

The obtained polymer was dissolved in hexafluoropropanol and subjected to 500 MHz ¹ H-NMR analysis, and as a result, dimer acid units were 1.13 mol and poly (tetramethylene oxide) glycol repeating units were 100 mol per terephthalic acid unit.
It contained 7.61 mol.

Also, this copolyester is heated to 280 ° C to form a film of about 50μ in a hot press, which is then quenched with water to obtain a substantially amorphous quenched film, which is heated at a rate of 20 ° C / min.
DSC measurement is performed, and the melting point (T
m) was determined to be Tm of 249 ° C.

The copolyester pellet obtained was heated at 120 ° C for 12 hours.
rs After vacuum drying, sandwich between Teflon-coated iron plates, use a 1m / m thick spacer to heat press mold at 280 ℃, and immediately transfer to another heat press set at 150 ℃ and hold for 5 minutes. After that, the sheet was cooled and formed into a substantially non-oriented and fully crystallized sheet having a thickness of 1 m / m.

Tensile test pieces were prepared from this sheet with a preheated rubber No. 2 dumbbell punching die.

This test piece was subjected to a tensile test using an Instron universal tester at 23 ° C. and a tensile speed of 0.5 cm / min. An average value was obtained by performing n = 5. Table 1 shows the tensile property values.

Example 2 After the esterification reaction of terephthalic acid and ethylene glycol was carried out in the same manner as in Example 1, the solution was fed to a polymerization tank and 43 g of sebacic acid, 43 g of poly (tetramethylene oxide) glycol having a molecular weight of about 2000, and Irganox. 3.5 g of 1010 (trade name, manufactured by Ciba Geigy) was added. After that, polycondensation was performed in the same manner as in Example 1 to obtain a pellet of copolyester. The intrinsic viscosity of the obtained polymer is 0.72.
It was dl / g. Compositional analysis from ¹ H-NMR spectrum showed that terephthalic acid 100
The sebacic acid unit was 2.81 mol and the repeating unit of poly (tetramethylene oxide) glycol was 7.48 mol per mol.

Example 3 After the esterification reaction of terephthalic acid and ethylene glycol was carried out in the same manner as in Example 1, 10 g of dimer acid (Versadim 288 made by Henkel Japan Ltd.) and a poly (tetra-tetrahydrofuran) having a molecular weight of about 2000 were fed to the polymerization tank. Methylene oxide) glycol
43 g and 3.5 g of Irganox 1010 (trade name, manufactured by Ciba Geigy) were added. After that, polycondensation was performed in the same manner as in Example 1 to obtain a pellet of copolyester. The intrinsic viscosity of the obtained polymer was 0.76 dl / g. Terephthalic acid unit 1 in composition analysis from ¹ H-NMR spectrum
With respect to 00 mol, 0.23 mol of dimer acid units and 7.70 of repeating units of poly (tetramethylene oxide) glycol
It was contained in moles.

Example 4 After the esterification reaction of terephthalic acid and ethylene glycol was carried out in the same manner as in Example 1, 43 g of dimer acid and 65 g of poly (tetramethylene oxide) glycol having a molecular weight of about 2000 were fed to the polymerization tank. 3.5 g of Irganox 1010 (trade name, manufactured by Ciba-Geigy) was added. After that, polycondensation was performed in the same manner as in Example 1 to obtain a copolyester. The intrinsic viscosity of the obtained polymer was 0.84 dl / g. Terephthalic acid unit 1 in composition analysis from ¹ H-NMR spectrum
The dimer acid unit was 1.07 mol and the repeating unit of poly (tetramethylene oxide) glycol was 10.2 mol per 00 mol.

Example 5 After the esterification reaction of terephthalic acid and ethylene glycol was carried out in the same manner as in Example 1, the solution was fed to a polymerization tank,
43 g of azelaic acid, 43 g of poly (tetramethylene oxide) glycol having a molecular weight of about 2000, and 3.5 g of Irganox 1010 (trade name, manufactured by Ciba-Geigy) were added. After that, polycondensation was performed in the same manner as in Example 1 to obtain a pellet of copolyester. The obtained polymer has an intrinsic viscosity of 0.65
It was dl / g. Composition analysis from ¹ H-NMR spectrum showed that azelaic acid unit was 2.98 per 100 mol of terephthalic acid.
It contained 7.42 mol of repeating units of poly (tetramethylene oxide) glycol.

Example 6 After carrying out an esterification reaction of terephthalic acid and ethylene glycol in the same manner as in Example 1, the solution was fed to a polymerization tank,
Okamura Oil Co., Ltd.SL-20 (HOOC (CH ₂ ) ₁₈ COOH 85-9
5%, HOOC (CH ₂ ) ₁₄ COOH 4-10%) 43g, molecular weight about 2
43 g of 000 poly (tetramethylene oxide) glycol,
Irganox 1010 (trade name, manufactured by Ciba Geigy) 3.5 g
Was added. After that, polycondensation was performed in the same manner as in Example 1 to obtain a pellet of copolyester. The polymer obtained had an intrinsic viscosity of 0.70 dl / g. The composition of the ¹ H-NMR spectrum was analyzed by using the signal of the CH ₂ group adjacent to the carbonyl group, and the unit of the aliphatic dicarboxylic acid was 1.70 mol per 100 mol of terephthalic acid, poly (tetramethylene oxide). It contained 7.52 moles of glycol repeating units.

Comparative Example 1 By the polymerization method of Example 1, pure PET having an intrinsic viscosity of 0.72 dl / g was polymerized.

Comparative Example 2 After the esterification reaction of terephthalic acid and ethylene glycol was carried out in the same manner as in Example 1, 43 g of only poly (tetramethylene oxide) glycol having a molecular weight of about 2000 was added to the polymerization tank. After that, polycondensation was performed in the same manner as in Example 1 to obtain a copolyester. The intrinsic viscosity of the obtained polymer was 0.74 dl / g. Also, ¹ H-NM
Composition analysis from the R spectrum revealed that 7.58 mol of repeating units of poly (tetramethylene oxide) glycol were contained per 100 mol of terephthalic acid units.

Comparative Example 3 A copolyester was obtained in the same manner as in Example 1 except that only 43 g of dimer acid was added. Intrinsic viscosity is 0.68dl / g
It was. Composition analysis from ¹ H-NMR spectrum revealed that dimer acid unit was contained in an amount of 0.89 mol per 100 mol of terephthalic acid unit.

Comparative Example 4 After the esterification reaction of terephthalic acid and ethylene glycol was carried out in the same manner as in Example 1, the solution was fed to a polymerization tank and dimer acid 155 g, poly (tetramethylene oxide) glycol 155 g having a molecular weight of about 2000, and Irganox. 3.5 g of 1010 (trade name, manufactured by Ciba Geigy) was added. After that, polycondensation was performed in the same manner as in Example 1, and the intrinsic viscosity was 0.90 dl / g.
Of polyester was obtained. Compositional analysis by ¹ H-NMR spectrum revealed that the dimer acid unit was 4.02 mol and the repeating unit of poly (tetramethylene oxide) glycol was 24.8 mol based on 100 mol of the terephthalic acid unit.

Comparative Example 5 After the esterification reaction of terephthalic acid and ethylene glycol was carried out in the same manner as in Example 1, 43 g of adipic acid and 43 g of poly (tetramethylene oxide) glycol having a molecular weight of about 2000 were added to the polymerization tank. It was After that, polycondensation was performed in the same manner as in Example 1 to obtain a polyester having an intrinsic viscosity of 0.65 dl / g. ^{From 1} H-NMR spectrum, based on 100 moles of terephthalic acid units, 3.12 moles of adipic acid and 6.52 moles of repeating units of poly (tetramethylene oxide) glycol were used.
It was contained in moles.

For the samples of Examples 1 to 6 and Comparative columns 1 to 5, Tm (melting point) was determined by DSC measurement by the method described in Example 1,
Further, a tensile test was conducted. The results are shown in Table 1.

[Effects of the Invention] According to the present invention, a copolymerized polyethylene terephthalate having improved toughness and improved brittleness, which is a drawback thereof, can be obtained without impairing the high melting point and high rigidity which are characteristics of conventional polyethylene terephthalate.

Claims (5)

[Claims] 1. A copolymerized polyester substantially composed of structural units represented by the following (I) to (IV): _{(III) OCH 2 -CH 2 -O} (IV) OCH 2 CH 2 CH 2 CH 2 -O n ( where, R represents a divalent group obtained by removing a carboxyl group from an aliphatic dicarboxylic acid or 9 carbon atoms And n is an integer of 8 to 84.) (I) is bound to (III) and / or (IV), (II) is bound to (III) and / or (IV) And substantially the total number of moles of (I) and (II) is (III)
Is equal to the total number of moles of (IV), and (II) is 0.2 to 5 moles per 100 moles of (I) in the copolyester, and (IV) is CH ₂ CH ₂ CH ₂ CH ₂ O. 3 repeat units
The copolyester is characterized by being contained in a proportion of up to 15 mol and having an intrinsic viscosity in the range of 0.5 to 1.5. 2. In the structural unit (II), R is selected from the group consisting of azelaic acid, sebacic acid, dodecanedicarboxylic acid, hexadecanedicarboxylic acid, eicosandicarboxylic acid, dimer acid and hydrogenated dimer acid. The copolyester according to claim 1, which is a divalent group obtained by removing a carboxyl group from one or more dicarboxylic acids. 3. In the structural unit (II), R is a carboxyl group selected from at least one dicarboxylic acid selected from the group consisting of azelaic acid, sebacic acid, dodecanedicarboxylic acid, hexadecanedicarboxylic acid, and eicosandicarboxylic acid. The copolyester according to claim 1, which is a divalent group excluding. 4. In the structural unit (II), R is a divalent group obtained by removing a carboxyl group from at least one dicarboxylic acid selected from the group consisting of dimer acid and hydrogenated products thereof. The copolyester according to item 1. 5. In the structural unit (IV), n is 8 or more and 28.
The copolyester according to claim 1, which is as follows.