JP2006291068A - Soft copolyester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a soft polyester hard to bleed-out its polyester oligomer, and small in lowering of gloss over time. <P>SOLUTION: This soft copolyester is obtained by esterification and then polycondensation of a terephthalic acid component (a), a dicarboxylic acid component (b) other than the terephthalic acid component, an ethylene glycol component (c), a polyoxytetramethylene glycol component (e) having a number average molecular weight of 500-2,500, and a 5-sodium sulfoisophthalic acid or its diester derivative component (f), or a terephthalic acid component (a), an ethylene glycol component (c), a diol component (d) other than ethylene glycol and polyoxytetramethylene glycol, polyoxytetramethylene glycol component (e) having a number average molecular weight of 500-2,500, and a 5-sodium sulfoisophthalic acid or its diester derivative component (f). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a soft copolyester used for various molding materials.

  Polyesters represented by polyethylene terephthalate (PET) are widely used as materials for bottles and sheets because of their excellent transparency and mechanical properties. The polyester is usually obtained by esterification and / or transesterification of a dicarboxylic acid component and a diol component, and taking out the diol component out of the reaction system under reduced pressure and performing a polycondensation reaction. At this time, if a terephthalic acid component and an ethylene glycol component or a 1,4-butanediol component are used, a homopolymer of PET or polybutylene terephthalate (PBT) can be obtained, respectively, but these monomer components constituting PET or PBT Various copolyesters can be obtained by adding other dicarboxylic acid components and / or diol components. In particular, when polyoxytetramethylene glycol is copolymerized, flexibility can be imparted, and when another monomer is copolymerized to be amorphous, a soft copolyester resembling a soft vinyl resin can be obtained (for example, Patent Literatures 1 to 3).

However, the glass transition temperature (Tg) of such a soft copolymer polyester is often room temperature, that is, 25 ° C. or less, and after the molding, it is exposed to a temperature above the glass transition temperature for a long period of time. There has been a problem that the oligomer in the polyester bleeds out, part of which becomes fine crystals and the gloss of the surface of the molded article is lost.
Japanese Patent No. 3270185 JP 2000-302888 A JP 2002-363271 A

  An object of the present invention is to provide a soft polyester which is less likely to bleed out of a polyester oligomer and has little gloss deterioration over time.

In the present invention, at least the following (a), (b), (c), (e), and (f) components are subjected to esterification reaction, and then obtained by polycondensation. It is a soft copolyester having an intrinsic viscosity [η] of 25 ° C. and 0.80 to 1.20 dl / g.
(A) terephthalic acid component,
(B) Dicarboxylic acid components other than terephthalic acid: 20 to 80 mol parts (relative to 100 mol parts of terephthalic acid component),
(C) ethylene glycol component: 145 to 300 mol parts (relative to 100 mol parts of terephthalic acid component),
(E) Polyoxytetramethylene glycol component having a number average molecular weight of 500 to 2500: 1 to 15 mol parts (based on 100 mol parts of terephthalic acid component),
(F) 5-sodium sulfoisophthalic acid or its diester derivative component: 0.3 to 2.5 mol parts (based on 100 mol parts of terephthalic acid component).

Further, the present invention provides a glass transition temperature obtained by subjecting at least the following components (a), (c), (d), (e), and (f) to an esterification reaction and then polycondensation: It is a soft copolyester having an intrinsic viscosity [η] of 10 to 25 ° C. and a viscosity of 0.80 to 1.20 dl / g.
(A) terephthalic acid component,
(C) ethylene glycol component: 50 to 100 mol parts (based on 100 mol parts of terephthalic acid component),
(D) Diol components other than ethylene glycol and polyoxytetramethylene glycol: 20 to 70 mol parts (relative to 100 mol parts of terephthalic acid component),
(E) Polyoxytetramethylene glycol component having a number average molecular weight of 500 to 2500: 1 to 15 mol parts (based on 100 mol parts of terephthalic acid component),
(F) 5-sodium sulfoisophthalic acid or its diester derivative component: 0.3 to 2.5 mol parts (based on 100 mol parts of terephthalic acid component).

  Even when the soft copolymer polyester of the present invention is exposed to a temperature equal to or higher than the glass transition temperature, the bleed out of the oligomer hardly occurs, and the gloss of the surface of the molded product is hardly reduced over time.

  The component (a) used in the soft copolymer polyester of the present invention is a terephthalic acid component.

Next, the component (b) used in the soft copolymer polyester of the present invention will be described.
The component (b) is a dicarboxylic acid component other than the terephthalic acid component.
(B) The usage-amount of a component is 20-80 mol parts with respect to 100 mol parts of (a) terephthalic acid components. By using the component (b) within this range, the crystallinity of the copolyester can be sufficiently lowered without greatly reducing the glass transition temperature, and amorphousness tends to be imparted.

  The component (b) is not particularly limited as long as it is a dicarboxylic acid other than terephthalic acid. For example, isophthalic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, anthracene dicarboxylic acid, 4,4 ′ -Diphenyldicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, sebacic acid, azelaic acid, dodecanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4 -Cyclohexanedicarboxylic acid, cyclopentanedicarboxylic acid, 4,4'-dicyclohexyldicarboxylic acid and the like. Among these, at least one of isophthalic acid and adipic acid is particularly preferable.

The component (c) used in the soft copolymer polyester of the present invention is an ethylene glycol component.
When the component (c) is used in combination with the component (a) and the component (b) described above and the component (e) and the component (f) described later, (a) with respect to 100 parts by mole of the terephthalic acid component, When used in the range of 145 to 300 parts by mole, and when used in combination with the component (a) described above and the component (d), component (e) and component (f) described below, (a) a terephthalic acid component It is used in the range of 50 to 100 mol parts with respect to 100 mol parts. By using the component (c) within this range, the esterification reaction and the polycondensation reaction tend to proceed without problems.

Next, the component (d) used in the soft copolymer polyester of the present invention will be described.
The component (d) is a diol component other than ethylene glycol and polyoxytetramethylene glycol.
(D) The usage-amount of a component is 20-70 mol part with respect to 100 mol part of (a) terephthalic acid components. By using the component (d) within this range, the crystallinity of the copolyester can be sufficiently lowered without greatly reducing the glass transition temperature, and the transparency tends to be improved.

  The component (d) is not particularly limited as long as it is a diol component other than ethylene glycol and polyoxytetramethylene glycol. For example, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1 , 3-butanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,4-bis (2-hydroxyethoxy) Examples include benzene, bisphenol A ethylene oxide adduct, and bisphenol A propylene oxide adduct. Among these, at least one selected from 1,4-butanediol, 1,4-cyclohexanedimethanol, and neopentyl glycol is particularly preferable.

Next, (e) component used for the soft copolyester of this invention is demonstrated.
The component (e) is a polytetramethylene glycol component having a number average molecular weight of 500 to 2500, and is used in the range of 1 to 15 parts by mole with respect to 100 parts by mole of the (a) terephthalic acid component. By using the component (e) within this range, a soft copolymer polyester excellent in flexibility and transparency tends to be obtained without impairing the copolymerizability. (E) As for the lower limit of the usage-amount of a component, 5 mol part or more is preferable, and the upper limit of this usage-amount is preferable 11 mol part or less.

  Moreover, when the number average molecular weight of the polyoxytetramethylene glycol component is in the range of 500 to 2500, a soft copolymer polyester excellent in flexibility and transparency tends to be obtained without impairing the copolymerizability. The lower limit of the number average molecular weight is preferably 650 or more, and the upper limit is preferably 2000 or less.

  In addition, since the component (e) may cause thermal decomposition, it is preferably used together with one kind of general stabilizers such as hindered phenols, phosphorous acids, thioethers, or combinations thereof. These stabilizers are preferably used in an amount of 10 parts by mass or less with respect to 100 parts by mass of component (e) so that there is no problem in the progress of the polycondensation reaction.

Next, the component (f) used in the soft copolymer polyester of the present invention will be described.
The component (f) is 5-sodium sulfoisophthalic acid or a diester derivative thereof. By using the component (f), the bleed out of the oligomer can be suppressed, and the deterioration of the gloss of the surface of the molded product over time tends to be suppressed.

  In general, in a copolyester containing a terephthalic acid component and an ethylene glycol component as constituent units, even if there are multiple types of dicarboxylic acid components and diol components other than these, esterification reaction, transesterification reaction or polycondensation In the course of the reaction, ethylene terephthalate cyclic trimer is formed as a by-product with a certain probability commensurate with its composition. This cyclic trimer is crystalline and its melting point is about 320 ° C. Even when general PET is melted and molded, the cyclic trimer is released from the resin and is not easily melted in powder form. It may become. In the case of copolyester, the glass transition temperature is lower than that of PET, so it is in a rubber state even at room temperature or lower, and even if it is not melted, the polyester molecular chain is sewn and the cyclic trimer oozes out, and the resin surface A minute crystal is made in this, and glossiness is gradually lost.

  In the copolymerized polyester of the present invention, by copolymerizing the component (f), a part of the copolymerized polyester molecular chain and the cyclic trimer are constrained by ionic bonds, and the bleeding out of the cyclic trimer is inhibited. It is thought that there is.

(F) Although the usage-amount of a component is not restrict | limited in particular, 0.3-2.5 mol part is preferable with respect to 100 mol part of (a) terephthalic acid components. When the amount of component (f) used is within this range, the above-mentioned effects tend to be obtained.
The component (f) is not particularly limited, and examples thereof include dimethyl 5-sodium sulfoisophthalate, diethyl 5-sodium sulfoisophthalate, and bis (2-hydroxyethyl) 5-sodium sulfoisophthalate.

In the soft copolyester of the present invention, in addition to the components (a) to (f) described above, a trifunctional or higher monomer, for example, trimellitic acid, as long as it does not interfere with the polycondensation of the reaction mixture, if necessary. Polyhydric carboxylic acids such as pyromellitic acid and acid anhydrides thereof, and polyhydric alcohols such as glycerin, trimethylolpropane, pentaerythritol, and sorbitol can be used.
Although the usage-amount of a trifunctional or more monomer is not restrict | limited, It is preferable that it is 3 mol part or less with respect to 100 mol part of (a) terephthalic acid components.

  The glass transition temperature of the soft copolyester of the present invention is -10 to 25 ° C. When the glass transition temperature is within this range, the flexibility, roll peelability and transparency tend to be good. The lower limit of the glass transition temperature is preferably −5 ° C. or higher, and the upper limit is preferably 15 ° C. or lower.

  The intrinsic viscosity [η] of the soft copolymer polyester of the present invention is 0.80 to 1.20 dl / g. When the intrinsic viscosity is within this range, the soft copolyester has sufficient resin strength and tends to have a melt viscosity with no problem in melt molding by the T-die extrusion method or the like. The lower limit value of the intrinsic viscosity is preferably 0.85 dl / g or more, and the upper limit value of the intrinsic viscosity is preferably 1.15 dl / g or less.

  The soft copolyester of the present invention is obtained by subjecting the aforementioned component (a), component (b), component (c), component (e), and component (f) to an esterification reaction, followed by polycondensation. Polyester or polyester obtained by subjecting the component (a), component (c), component (d), component (e), and component (f) to an esterification reaction and then polycondensation.

  The reaction temperature of the esterification reaction is not particularly limited, but is preferably 220 to 265 ° C. When the esterification reaction is completed, the reaction mixture is transferred to a polycondensation reactor, a polycondensation catalyst is added, and ethylene glycol is finally added to the reactor under a pressure of 265 to 285 ° C. and 1.0 kPa or less. The polycondensation reaction is carried out by further distilling off.

  After the polycondensation reaction is completed, the soft copolyester of the present invention is preferably taken out from the reactor as a strand, cut into 8 to 18 ° C. cooling water, and pelletized. By using the cooling water in this temperature range, the pellets are not fused after draining, and the strands tend to be excessively cooled and not crushed during cutting. The lower limit value of the cooling water temperature is more preferably 10 ° C. or higher, and the upper limit value is more preferably 15 ° C. or lower.

  In the soft copolyester of the present invention, an additive of 0.4% by mass or less can be used with respect to the copolyester pellet so that fusion does not occur even during storage and transportation after the pellet is formed. .

  The additive used is not particularly limited as long as it prevents fusion of the pellets. For example, metal salts such as calcium stearate and zinc stearate, polyether, polyamide, polyolefin, polymethyl methacrylate, polycarbonate Resin powder such as silica, inorganic particles such as silica, talc, kaolin and calcium carbonate, pigments such as titanium oxide and carbon black, fluorescent brightener, ultraviolet absorber, antioxidant, mold release agent, antistatic agent, difficult A flame retardant, a light resistance agent, etc. are mentioned, These can be used individually or in combination of 2 or more types. In particular, powders of silica, calcium stearate, zinc stearate, polyolefin, polymethyl methacrylate resin, and the like are preferable.

  The average particle diameter of the additive is not particularly limited, but is preferably 0.3 to 20 μm. When the average particle size is within this range, there is no aggregation of additives, and when formed into a film or the like, there is less fuzz and the antiblocking effect tends to increase. The lower limit value of the average particle diameter of the additive is more preferably 0.5 μm or more, and the upper limit value is more preferably 15 μm or less.

Hereinafter, it demonstrates in detail based on an Example. In Examples and Comparative Examples, copolymer polyesters were evaluated using the following methods.
(1) Intrinsic viscosity [η] (dl / g)
Measurement was performed in a mixed solvent of equal mass of phenol / tetrachloroethane at 25 ° C.
(2) Glass transition temperature Tg (° C)
According to JIS K-7121, the shoulder value measured at a rate of temperature increase of 10 ° C./min with a differential scanning calorimeter (DSC) was defined as the glass transition temperature (° C.).

(3) Transparency Copolymerized polyester is formed into a film by an extrusion film forming machine (Thermo Plastic Industry Co., Ltd., 40 mm single screw extruder) so that the resin temperature is 250 ° C. and the chill roll temperature is 5 ° C. A 200 μm polyester sheet was obtained, and the transparency of the sheet was evaluated in five stages according to the following criteria.
“5”: Almost transparent, and characters and designs on the other side can be clearly identified through the sheet.
“4”: Almost transparent but inferior to evaluation “5”.
“3”: There is turbidity.
“2”: Slightly clouded, and characters and designs on the other side can be barely identified through the sheet, but it is not suitable for applications that require transparency.
“1”: Cloudy, and the characters and designs on the other side cannot be identified through the sheet.

(4) Sheet surface gloss A 15 cm side square was cut out from the polyester sheet produced in the transparency test, and this test piece was heated in an oven at 60 ° C. for 10 days to obtain a 75 ° glossiness before and after heat treatment as a handy gloss. It measured with the meter (Nippon Denshoku Industries PG-1). The gloss retention after heat treatment (gloss after heat treatment / gloss before heat treatment × 100%) is preferably 80% or more, more preferably 85% or more, further preferably 90% or more, and particularly preferably 95% or more.

Example 1
In an esterification reactor, 129 kg (779 mol) of terephthalic acid, 58.3 kg (351 mol) of isophthalic acid, 106 kg (1715 mol) of ethylene glycol, 0.209 kg (1.56 mol) of trimethylolpropane, dimethyl 5-sodium sulfoisophthalate 46 kg (11.7 mol), polyoxytetramethylene glycol 78.2 kg (78.2 mol) with a number average molecular weight of 1000, and tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4) as stabilizer -Hydroxyphenyl) propionate] 5.86 kg of methane was charged, a nitrogen pressure of 300 kPa was applied, the generated water was distilled out of the reaction system, the temperature was raised to 260 ° C., and an esterification reaction was performed for 180 minutes. The reactor was returned to atmospheric pressure, 90.0 g (0.860 mol) of germanium dioxide and 12.0 g (0.066 mol) of triethyl phosphate were added as polycondensation catalysts, and after 15 minutes, the reaction mixture was transferred to the polycondensation reactor. Liquid. After 5 minutes, depressurization was started, and finally at 0.10 kPa, polycondensation was performed at 260 ° C. while distilling ethylene glycol out of the reaction system. After 120 minutes, a predetermined axial torque was reached. The polycondensation reaction was stopped. Five minutes later, a nitrogen pressure of 0.2 MPa was applied, and the resin was taken out from the reactor in the form of a strand, and was cut in cooling water at 13 ° C. to obtain a copolyester 1 pellet.

In addition, Table 1 shows the mole parts of the feed when the terephthalic acid component is converted to 100 mole parts. However, about a stabilizer, the mass part of preparation when a polyoxytetramethylene glycol component is converted into 100 mass parts is shown.
The obtained copolyester 1 had an intrinsic viscosity [η] of 0.95 dl / g and Tg of −4 ° C.
Sheets of copolymerized polyester 1 were prepared and evaluated for transparency and gloss retention before and after heat treatment. These results are shown in Table 1. Copolyester 1 was rich in flexibility and had good transparency and gloss retention.

Examples 2-8
Except for changing the charged composition as shown in Table 1, the same operations as in Example 1 were performed to obtain copolymer polyester pellets 2 to 8. The evaluation results are shown in Table 1.

Comparative Example 1
Except for changing the charged composition as shown in Table 2, the same operation as in Example 1 was carried out to obtain pellets of copolymerized polyester 9. The evaluation results are shown in Table 2.
The sheet produced from the copolyester 9 pellets was flexible but had poor transparency due to the use of polyoxytetramethylene glycol having a high molecular weight.

Comparative Example 2
Except for changing the charged composition as shown in Table 2, the same operation as in Example 1 was performed to obtain pellets of copolymerized polyester 10. The evaluation results are shown in Table 2.
The sheet obtained from the copolyester 10 pellets had good gloss retention, but had a high Tg and no flexibility due to the small amount of polyoxytetramethylene glycol used. Moreover, transparency was also inferior.

Comparative Example 3
Except for changing the charged composition as shown in Table 2, the same operation as in Example 1 was carried out to obtain pellets of copolymerized polyester 11. The evaluation results are shown in Table 2.
The sheet obtained from the pellets of the copolyester 11 has a large amount of polyoxytetramethylene glycol and has a high intrinsic viscosity [η] of 1.25 and a poor film formation state. there were.

Comparative Example 4
Except for changing the charged composition as shown in Table 2, the same operation as in Example 1 was carried out to obtain pellets of copolymerized polyester 12. The evaluation results are shown in Table 2.
The sheet obtained from the copolyester 12 pellets was flexible, but because polyoxytetramethylene glycol having a high molecular weight was used, the transparency was poor and the gloss retention was poor.

Comparative Example 5
Except for changing the charged composition as shown in Table 2, the same operation as in Comparative Example 1 was carried out to obtain pellets of copolymerized polyester 13. The evaluation results are shown in Table 2.
The sheet obtained from the pellets of the copolyester resin 13 had a high Tg and was not flexible because the amount of polyoxytetramethylene glycol used was small. Moreover, it was inferior to transparency.

Comparative Example 6
Except for changing the charged composition as shown in Table 2, the same operation as in Example 1 was carried out to obtain pellets of copolymerized polyester 14. The evaluation results are shown in Table 2.
The sheet obtained from the pellets of the copolyester 14 was inferior in transparency because of its large intrinsic viscosity [η] and poor film formation. Moreover, since Tg was low and the amount of 5-sodium sulfoisophthalic acid derivative used was small, bleeding out of the solid oligomer occurred, and the gloss retention was extremely poor.

Comparative Example 7
Except for changing the charged composition as shown in Table 2, the same operation as in Example 1 was performed to obtain pellets of copolymerized polyester 15. The evaluation results are shown in Table 2.
The sheet obtained from the pellets of copolymerized polyester 15 had a large amount of 5-sodium sulfoisophthalic acid derivative, so that solid oligomers bleed out and gloss retention was extremely poor.

Comparative Example 8
Except for changing the charged composition as shown in Table 2, the same operation as in Example 1 was performed to obtain pellets of copolymerized polyester 16. The evaluation results are shown in Table 2.
Since the sheet obtained from the pellets of the copolymerized polyester 16 has a large amount of the component (d), the intrinsic viscosity and Tg are lowered, the solid oligomer is bleed out, and the gloss retention is poor.

In addition, the stabilizers 1-3 in Tables 1-2 are the following compounds, respectively.
Stabilizer 1: Tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4-hydroxyphenyl) propionate] methane stabilizer 2: 3,9-bis [1,1-dimethyl-2- [ β- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] 2,4,8,10-tetraoxaspiro [5,5] -undecane stabilizer 3: 1,3,5 -Trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene

Claims (2)

At least the following (a), (b), (c), (e), and (f) components are esterified and then polycondensed to obtain a glass transition temperature of −10 to 25 ° C. A soft copolyester having a viscosity [η] of 0.80 to 1.20 dl / g.
(A) terephthalic acid component,
(B) Dicarboxylic acid components other than terephthalic acid: 20 to 80 mol parts (relative to 100 mol parts of terephthalic acid component),
(C) ethylene glycol component: 145 to 300 mol parts (relative to 100 mol parts of terephthalic acid component),
(E) Polyoxytetramethylene glycol component having a number average molecular weight of 500 to 2500: 1 to 15 mol parts (based on 100 mol parts of terephthalic acid component),
(F) 5-sodium sulfoisophthalic acid or its diester derivative component: 0.3 to 2.5 mol parts (based on 100 mol parts of terephthalic acid component). At least the following (a), (c), (d), (e), and (f) components are esterified and then polycondensed to obtain a glass transition temperature of −10 to 25 ° C. A soft copolyester having a viscosity [η] of 0.80 to 1.20 dl / g.
(A) terephthalic acid component,
(C) ethylene glycol component: 50 to 100 mol parts (based on 100 mol parts of terephthalic acid component),
(D) Diol components other than ethylene glycol and polyoxytetramethylene glycol: 20 to 70 mol parts (relative to 100 mol parts of terephthalic acid component),
(E) Polyoxytetramethylene glycol component having a number average molecular weight of 500 to 2500: 1 to 15 mol parts (based on 100 mol parts of terephthalic acid component),
(F) 5-sodium sulfoisophthalic acid or its diester derivative component: 0.3 to 2.5 mol parts (based on 100 mol parts of terephthalic acid component).