JP3421955B2 - Copolyester - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copolyester having a relatively low melting point, excellent crystallinity and excellent productivity and is widely used for fibers, films and various molding materials.

[0002]

2. Description of the Related Art Polyethylene terephthalate (P
Since aromatic polyesters represented by ET) have excellent physical properties, they are widely used in fibers, films, drinking bottles and the like. On the other hand, since naphthalate-based aromatic polyesters represented by polyethylene 2,6 naphthalate (PEN) have higher physical properties and heat resistance than PET, they are expected to be applied to products that are difficult to use with PET. The melting point is about 10 ° C higher (273 ° C) than the PET that has been widely used in the past, and therefore the conventional PET
Depending on the equipment specifications, PE
It has the drawback of producing equipment that cannot be applied to the production of N. From the viewpoint of polymer deterioration and stability, it is preferable to polymerize at the lowest temperature possible,
Further, from the viewpoint of energy saving and cost, it is advantageous that the polymerization can be carried out at a low temperature. Incidentally, in order to improve PEN for various purposes, it is preferable to copolymerize various compounds with PEN in JP-A-50-135333 and JP-B-5.
7-45772, JP-B-55-41247, and the like. However, when PEN is copolymerized with an acid component or a glycol component for the above-mentioned purpose, there is a drawback that crystallinity is significantly impaired, and dimensional stability and heat resistance are deteriorated, which limits the use of the product.

[0003]

SUMMARY OF THE INVENTION The present invention is a copolymer PE
An object of the present invention is to overcome the above-mentioned drawbacks of N and to obtain a PEN copolymerized polyester having a lower melting point and excellent crystallization characteristics and mechanical characteristics at the same time.

[0004]

Means for Solving the Problems In order to solve the above-mentioned problems, the inventors of the present invention have finally made the present invention as a result of intensive research. That is, the present invention relates to a polyester consisting of an ethylene naphthalate unit mainly composed of a naphthalene dicarboxylic acid residue and an ethylene glycol residue, and 0.1 to 10 mol of a glycol represented by the following general formula 2 as a copolymerization component. %, And has a cooling crystallization peak.

[0005]

[Chemical 2] (In the formula, R ¹ is a divalent straight-chain aliphatic having 2 to 20 carbon atoms.
Hydrocarbon group, aliphatic hydrocarbon group having side chain and aliphatic group
A hydrocarbon group having a ring , m and n are the same or different integers and represent 3 ≦ m + n <10)

The copolymerized polyester of the present invention has at least 8
0 mol% or more is obtained by using 2,6 naphthalenedicarboxylic acid or its ester-forming derivative as a dicarboxylic acid component and ethylene glycol or its ester-forming derivative as a glycol component. The melting point is PET
In order to lower the amount, at least 5 mol% is required when copolymerizing a conventionally known polyalkylene glycol or the like, but in the case of PEN, the naphthalene skeleton is more rigid than the terephthalic acid skeleton of PET, so a small amount of copolymerization is required. Crystallinity is significantly impaired by the ingredients. Therefore, PEN has a limit in copolymerization of a general-purpose monomer that is inferior in thermal stability, dimensional stability, and mechanical properties and only causes a decrease in melting point. In view of this point, in the present invention, in order to improve the crystallinity of PEN without impairing the functionality of the copolymerized PEN, the glycol component represented by the general formula 2 is 0.1 to 0.1 in the copolymerization of PEN. 10 mol%, preferably 3-1
It is characterized by adding 0 mol% and more preferably 5 to 10 mol% for copolymerization.

In the formula (2), R ¹ has 2 to 2 carbon atoms.
0 divalent straight-chain aliphatic hydrocarbon group, aliphatic having side chain
The hydrocarbon group and the hydrocarbon group having an aliphatic ring , m and n are the same or different integers and represent 3 ≦ m + n <10. R ¹
Examples of the specifically _{- (CH 2) 6 -,} - (CH
₂ ) Having a linear aliphatic hydrocarbon group such as _10- , an aliphatic hydrocarbon group having a side chain such as 2-methylpropyl group, 1-methylpropyl group, neopentyl group, or an aliphatic ring such as cyclohexyl group Examples of the hydrocarbon group include an aliphatic hydrocarbon group having a side chain, of which a neopentyl group is most preferable.

In the present invention, the glycol represented by the general formula 2 does not distill during the polycondensation reaction when obtaining the copolyester, so that the content in the produced polyester is controlled to be constant. , Products with stable quality can be obtained. Further, the obtained polyester is excellent in crystallinity at the same time as the melting point is lowered. Note The synthesis of glycol represented by the general formalized 2, respectively HO-R ¹ -
It can be synthesized by adding ethylene oxide to a glycol represented by OH, such as neopentyl glycol or propylene glycol, by a conventional method. Further, glycols synthesized by adding other alkylene oxides such as propylene oxide may also be used in combination as long as the effects of the present invention are not impaired.

In the general formula 2, in the case of a glycol represented by HO-R ¹ -OH in which both m and n are 0 or a modified glycol having an average value of m + n smaller than 3, it is obtained together with the problem of distilling. In addition, there is a drawback that the melting point of polyester is large and the crystallinity is poor, and m + n
Is larger than 10, it is not preferable because it causes a problem of deterioration of light resistance and lacks practicality. The preferred range is 3-6.

In the present invention, 5-metal sulfoisophthalic acid, terephthalic acid and isophthalic acid are based on the glycol-copolymerized PEN represented by the general formula 2 but within the range not degrading the quality of the copolyester. , An aromatic dicarboxylic acid such as naphthalenedicarboxylic acid isomer, biphenyldicarboxylic acid or an ester-forming derivative thereof,
Aliphatic dicarboxylic acids such as glutaric acid, adipic acid, and azelaic acid, or ester-forming derivatives thereof, oxycarboxylic acids such as paraoxybenzoic acid, or ester-forming derivatives thereof, and the like can be used in small amounts as copolymerization components.

As the method for obtaining the copolyester of the present invention, there are conventional methods such as a method of transesterifying a dicarboxylic acid ester and a glycol and then polycondensing, a method of esterifying a dicarboxylic acid and a glycol and then polycondensing. It can be obtained according to the polyester manufacturing method. As the dicarboxylic acid, 2,6 naphthalenedicarboxylic acid or an ester-forming derivative thereof and a compound represented by the general formula 2
When a glycol component or an ester-forming derivative thereof represented by is used, these may be reacted at the same time, or these dicarboxylic acids may be separately reacted with the glycol component and mixed in the polycondensation reaction step. May be. The catalyst that accelerates these reactions is a catalyst usually used in polyester production, and for example, a metal compound such as sodium, magnesium, calcium, zinc, manganese, antimony, germanium, titanium is used.

There is no limitation on the additives such as catalysts, matting agents, stabilizers, etc. used for obtaining the copolyester of the present invention, and the obtained polyester is molded by a known method such as spinning, film formation, Molded.

[0013]

The reason why the copolyester of the present invention has excellent crystallization characteristics is that glycol as shown in the chemical formula 2 facilitates rearrangement of molecular chains required for crystallization due to its flexible molecular structure. It is considered to enhance crystallization.
That is, since PEN has a naphthalene ring that is more rigid than PET terephthalic acid, it is likely that a small amount of copolymerization hinders rearrangement of molecular chains associated with crystallization and tends to become amorphous.

[0014]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples. The method for evaluating polymer properties was as follows. a Intrinsic viscosity: The polymer was dissolved in a phenol / 1,1,2,2-tetrachloroethane = 3/2 mixed solution at a concentration of 0.4 g / dl and measured at 30 ° C. b Polymer crystallinity: differential scanning calorimeter (Shimadzu TA-5
0) under an argon atmosphere, the temperature rise crystallization temperature when the temperature is raised at 10 ° C./min, and the temperature decrease crystallization temperature when the polymer is melted at 300 ° C. and the temperature of the molten polymer is lowered at 10 ° C./min. Judged in.

Example 1 An autoclave was charged with 506 parts by weight of 2,6 dicarboxynaphthalenedimethyl ester and 295 parts of ethylene glycol.
By weight, 0.03 mol% of manganese acetate as a catalyst and 0.02 mol% of antimony trioxide (based on 2,6 dicarboxynaphthalenedimethyl ester) were added, and the transesterification reaction with ethylene glycol was conducted at 160 to 230 ° C.
I did it in. When the theoretical amount of methanol was deposited, 1.2 times molar amount of trimethyl phosphate was added to manganese acetate. Next, the temperature was maintained at 235 ° C., and the glycol compound (average m + n = 5) shown in the following general formula 3 was added to 6
3 parts by weight (10 mol% in copolymerized PEN) were added.

[0016]

[Chemical 3] Next, after reacting with stirring at the same temperature for 10 minutes, the pressure was reduced while raising the temperature to 285 ° C., and finally to 0.1 mmHg, and polymerization was performed at the same temperature for 30 minutes. After the completion, it was taken out as a strand. The obtained polymer has an intrinsic viscosity of 0.5.
3, the melting point by DSC is 261 ° C, the temperature rise crystallization temperature is 2
The crystallization temperature was 03 ° C, and the temperature-falling crystallization temperature was 193 ° C.

Example 2, Comparative Examples 1 to 4 In Example 1, polymerization was carried out by changing the amount of the glycol component represented by Chemical formula 3 (indicated as G3 component in the table) as shown in Table 1 to obtain crystals. The oxidization temperature (in the table, ND indicates that it is not detected) was evaluated. The results are also shown in Table 1.

[0018]

[Table 1]

[0019]

As is clear from Table 1, in Comparative Example 1 containing a small amount of G3 component, the melting point decrease was smaller than that of the PEN homopolymer in Comparative Example 2, and as in Comparative Examples 3 and 4, 5-sodium-sulfone was used. Isophthalic acid diethylene glycol ester (labeled DIS in Table 1) and terephthalic acid (Table 1
Among them, the crystallinity is obviously impaired by the copolymerization with TPA). On the other hand, as shown in Examples 1 and 2 which are Examples of the present invention, it can be seen that copolymerization of a specific glycol component in a specific amount makes it possible to achieve both lowering of melting point and crystallinity. The present invention also uses a specific glycol as P
By copolymerizing with EN, synthesis of low-melting-point PEN copolymer, which has hitherto been demanded from the viewpoint of polymer deterioration and stability, energy saving and cost, can be achieved without impairing crystallinity. became. As a result, it becomes possible to manufacture using a conventional device, which greatly contributes to productivity and cost. Further, the copolyester of the present invention can be used for producing fibers, films and other molded articles, and is particularly expected to be used as fibers and films since it is excellent in processability and crystallization characteristics.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C08G 63/00-63/91

Claims (3)

(57) [Claims] 1. A polyester comprising an ethylene naphthalate unit mainly composed of a naphthalene dicarboxylic acid residue and an ethylene glycol residue, wherein a glycol represented by the following general formula 1 is used as a copolymer component.
Copolymerized polyester having 10 to 10 mol% and having a temperature-falling crystallization peak. [Chemical 1] (In the formula, R ¹ is a divalent straight-chain aliphatic having 2 to 20 carbon atoms.
Hydrocarbon group, aliphatic hydrocarbon group having side chain and aliphatic group
A hydrocarbon group having a ring , m and n are the same or different integers and represent 3 ≦ m + n <10) 2. The copolyester according to claim 1, wherein m + n is in the range of 3 to 6. 3. The copolyester according to claim 1, wherein R ¹ is a neopentyl group.