JP2698269B2 - Polyester block copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

This invention relates to a novel polyester block copolymer. More specifically, the present invention relates to a polyester block copolymer which is excellent in durability such as weather resistance and heat resistance, and is suitable for producing an elastic yarn having extremely excellent elastic recovery performance.

[0002]

2. Description of the Related Art An aromatic polyester is used as a hard component,
It is well known that a polyester block copolymer containing an aliphatic polyether or an aliphatic polyester as a soft component is used in various applications as a so-called polyester elastomer. However, these polyester elastomers have insufficient weather resistance and heat resistance. For example, the most commonly used polyester elastomer containing poly (oxytetramethylene) glycol as a soft component is used unless a stabilizer is used in combination. It has low stability and deteriorates until it becomes unusable in one to two months even at room temperature. This deterioration is further promoted when light is irradiated.

[0003] Polyester elastomers containing an aliphatic polyester as a soft component have better stability than the above-mentioned ones. However, unless a stabilizer is used, the molecular weight of the polyester elastomer is reduced within one week even at 100 ° C. In many cases, the initial characteristics deteriorate.

Therefore, when these conventional polyester elastomers are put to practical use, it is essential to use stabilizers such as ultraviolet absorbers and antioxidants in combination, but the stabilizing effect is small, and Unless increased, deterioration often occurs during long-term use. However, when a molded article to which a large amount of a stabilizer is added is post-processed and post-treated, a problem often occurs in that the stabilizer bleeds out or elutes.

In order to solve the above problems, the present inventors have previously considered that the conventional polyester block copolymers are inferior in durability, such as heat resistance and weather resistance, to soft components. It was found that the oxidation resistance and hydrolysis resistance of the aliphatic polyether or polyester were insufficient, and it was proposed to use a specific aromatic polyester component having excellent performance as a soft component ( Japanese Patent Application No. 2-137032).

[0006]

However, elastic yarns made of such a polyester block copolymer have good elastic recovery ability, but are required to have even higher elastic recovery ability depending on applications.

[0007] The present invention has been made in view of the above,
An object of the present invention is to provide a polyester block copolymer having improved weather resistance and heat resistance and excellent elastic recovery ability.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, it has been found that an aromatic polyester containing a specific diol compound having a methyl group in a side chain as a glycol component has excellent elastic recovery. The present invention has been found to have a function as a soft component for imparting performance and to be excellent in the above-mentioned durability, and reached the present invention.

That is, according to the present invention, phthalic acids are the main acid component, and the content of the diol compound represented by the following formula (I) is 50 mol% with respect to all glycol components.
A polyester segment (A) having a diol compound having 6 or more carbon atoms as a main glycol component,
Aromatic dicarboxylic acid component as main acid component, having 2 carbon atoms
A polyester block copolymer comprising an aliphatic α, ω-diol and / or a polyester segment (B) containing 1,4-cyclohexanedimethanol as a main glycol component;

[0010]

HOCH ₂ RCH ₂ OH (I) wherein R represents a C 4-7 aliphatic saturated hydrocarbon residue having at least one branched methyl group.

One component constituting the polyester block copolymer of the present invention is a diol compound having phthalic acids as a main acid component, a diol compound having 6 or more carbon atoms, and 50 mol% or more of the total glycol component represented by the following formula ( I)

[0012]

A diol compound represented by the formula: HOCH ₂ RCH ₂ OH (I) wherein R represents a C 4-7 aliphatic saturated hydrocarbon residue having at least one branched methyl group. It is a polyester segment (A) which is a main glycol component.

The phthalic acids include phthalic acid and isophthalic acid. The diol compounds having 6 or more carbon atoms include, in addition to the compound represented by the above general formula (I), HO ( Examples thereof include alkylene glycols such as hexamethylene glycol and decamethylene glycol represented by CH ₂ ) _n OH (n is 6 or more). Compounds represented by the general formula (I) include 3-methyl-1,5-pentanediol,
Methyl-1,8-octanediol, 4-methyl-1,
Examples thereof include 7-heptanediol, which may be used alone or in combination.

In the present invention, it is important that at least 50 mol% of the glycol component constituting the polyester segment (A) is a diol compound represented by the general formula (I). When the number of carbon atoms of R is 3 or less, and when the content of (I) is less than 50 mol%, the elastic recovery performance is undesirably reduced. On the other hand, when the carbon number of R is 8 or more, it is not preferable because it becomes difficult to obtain the diol compound. Here, the term “main” means at least 60 mol% or more, preferably 70 mol%.
The above components are composed of the above components, and the total of the acid components and / or glycol components composed of components other than the above components is 40 mol% with respect to the total acid components of the polyester segment (A).
Or less, preferably 30 mol% or less. Here, when an aliphatic dicarboxylic acid having 6 to 12 carbon atoms is used as a component other than the above, the elastic recovery performance at a low temperature is preferably improved.

Another component constituting the block copolymer of the present invention is an aliphatic α, ω-diol having 2 to 4 carbon atoms and / or 1,4-cyclohexanedimethanol as a main glycol component, and an aromatic component. A polyester segment (B) containing a dicarboxylic acid as a main acid component.
6 or more polyester (B ') has a melting point of 180 ° C or more,
It is important that the temperature is preferably 200 ° C. or higher. The term "main" means that other components may be copolymerized in an amount of 30 mol% or less, preferably 20 mol% or less, based on all the acid components of the polyester segment (B), as described above.

The aromatic dicarboxylic acid used in the polyester segment includes, for example, terephthalic acid,
Examples thereof include 2,6-naphthalenedicarboxylic acid and 4,4'-diphenyldicarboxylic acid, and examples of the aliphatic α, ω-diol include ethylene glycol, trimethylene glycol, and tetramethylene glycol. Above all, it has a characteristic that the crystallinity is good and the crystallization speed is high, so that the poly (tetramethylene terephthalate) segment, the poly (tetramethylene-2,6-naphthalenedicarboxylate) segment and the poly (1,4-)
(Cyclohexane dimethylene terephthalate) segment and the like are preferably used.

The block copolymer of the present invention comprises the polyester segment (A) and the polyester segment (B), and the ratio can be arbitrarily changed depending on the purpose. That is, in general, A: B may be set in the range of 90:10 to 30:70 in order to impart elastic recovery performance. In particular, when rubber elasticity is desired, the A portion is often 90:10 to 50:50. It is desirable (but weight ratio).

The above-mentioned block copolymer of the present invention can be obtained, for example, by polymerizing the high molecular weight polyesters (A ') and (B') consisting of the polyester segment (A) or the polyester segment (B) alone. It can be easily obtained by transesterification (redistribution). As a method of performing this transesterification reaction, a method of melt-mixing the above two polyesters in the presence of a catalyst is generally used.
Two important points are "how far to react" and "how to stop the reaction in that state".
The former point can be changed as appropriate depending on what kind of properties the polymer having is desired. The reaction conditions for that purpose are the type, amount and molecular weight of the polyester (A ') and polyester (B') used. It depends on various factors such as a stirring condition, a temperature, a catalyst and the like. Therefore, in practice, the polymer used, the composition,
After the equipment and the like are determined, the reaction conditions under which the desired polyester block copolymer can be obtained will be found.

At the time of this transesterification reaction, the melting point of the obtained polyester block copolymer is as follows:
It is important to react until the melting point of the used polyester (B ') becomes lower by 2 to 40C. If the decrease in the melting point is less than 2 ° C., the transesterification does not proceed sufficiently, and the resulting polymer is a mixture of polyester (A ′) and polyester (B ′) rather than a block copolymer. And no sufficient elastic recovery performance is exhibited. On the other hand, when the decrease in melting point is 40 ° C. or more, the transesterification reaction proceeds too much, the length of the polyester segment (B) of the obtained block copolymer becomes too short, and the crystallinity decreases and the elastic recovery is restored. It is not desirable because the performance becomes insufficient and becomes substantially equivalent to that of the random copolymer. Preferably, the obtained polymer has a 50% elongation elastic recovery of 80% when formed into fibers.
% Is desirable.

Next, "how to stop the transesterification reaction" is not necessarily a problem when the block copolymer after the reaction is molded immediately,
For example, in the case of once forming chips and then melting again to form a molded product, the transesterification reaction proceeds further during remelting and the properties of the block copolymer change, so it is necessary to stop the transesterification reaction. desirable. As a method for stopping this reaction, a method for deactivating the catalyst is generally used. For example, a titanium or tin catalyst is used as a transesterification catalyst, and phosphoric acid, phosphorous acid, phosphonic acid, phosphinic acid and derivatives thereof are used. Can be used to deactivate the catalytic ability.

In this method of deactivating the catalytic activity, the effect is reduced when the temperature becomes 260 ° C. or higher.
If the temperature exceeds 60 ° C., the catalytic activity cannot be completely stopped.) If the melting point of the polyester (B ′) exceeds 260 ° C., reaction and molding at a low temperature can be performed using a solvent, a plasticizer, or the like in advance. It is desirable to do so.

The intrinsic viscosity (measured in orthochlorophenol at 35 ° C.) of the polyester block copolymer thus obtained is preferably 0.4 or more, more preferably 0.6 or more. It can be easily achieved by using (A ') and (B') having high intrinsic viscosities and reacting them under such conditions that both polymers are not decomposed during the transesterification reaction to reduce the degree of polymerization. That is, for example, if the reaction temperature during the transesterification reaction is too high, thermal decomposition occurs,
If water, a glycol component and the like coexist in the reaction atmosphere, hydrolysis, glycol decomposition and the like will occur, and the intrinsic viscosity of the obtained block copolymer will decrease, which is not desirable.

The polyester block copolymer of the present invention comprises a branching agent, a sulfonate compound for imparting cationic dyeability, a phosphorus compound for imparting flame retardancy,
Other copolymerization components may be copolymerized, and
Pigments, dyes, fillers, flame retardants, stabilizers and the like may be contained.

[0024]

The polyester block copolymer of the present invention has the same elastic recovery performance as the conventional polyetherester block copolymer composed of polytetramethylene glycol and aromatic polyester. Despite this, it has extremely high oxidation resistance (long-term heat resistance, light resistance, etc.). Further, it has a feature that it is superior in hydrolysis resistance as compared with a polyester block copolymer containing an aliphatic polyester as a soft component.

Therefore, even if a stabilizer is not used in combination, it can be applied to a wide range of uses such as fibers, films and resins, taking advantage of the fact that it exhibits excellent flexibility and rubber elasticity and its durability is extremely improved. And its industrial value is extremely large.

[0026]

The present invention will be described in more detail with reference to the following examples. In the examples, "parts" indicates parts by weight, and the intrinsic viscosity is measured in orthochlorophenol at 35 ° C.

[0027]

Example 1 70 parts of dimethyl isophthalate, 12 parts of dimethyl terephthalate, 40 parts of decanedicarboxylic acid, 30 parts of hexamethylene glycol and 3-methyl-1,5
-120 parts of pentanediol was heated together with 0.07 parts of titanium tetrabutoxide to remove by-produced methanol and water. The reaction product was transferred to a reaction vessel capable of reducing pressure, and reacted under reduced pressure to obtain an amorphous polyester (A ') having an intrinsic viscosity of 0.97. This polyester (A ')
Then, polytetramethylene terephthalate (intrinsic viscosity 0.92) (polyester (B ')) obtained by separately polymerizing was added so as to be 75% by weight of polyester (A') and 25% by weight of polyester (B '). And 250 ° C
For 20 minutes under reduced pressure of 1 mmHg. The contents were cloudy at first, but became transparent from about 15 minutes. Twenty minutes later, 0.1 part of phenylphosphonic acid was added, and the mixture was stirred for another 10 minutes and then taken out. The intrinsic viscosity of the obtained polyester block copolymer was 0.98.

This polymer was discharged from a 12-hole die at 250 ° C. and wound at 400 m / min to obtain an elastic yarn. The elastic yarn had an elongation of 680% and a strength of 0.8 g / de. The elastic recovery was 99% when measured by recovering immediately after elongation by 50% (1.5 times the original length). .
This yarn was immersed in an aqueous solution of sodium hypochlorite at a pH of 7 adjusted to a chlorine concentration of 600 ppm at 60 ° C. for 2 hours, but the strength hardly decreased. When light irradiation was performed at 60 ° C. for 144 hours using a xenon tester, there was almost no coloring and the intensity was maintained at 80% or more.

[0029]

Example 2 70 parts of dimethyl isophthalate, 12 parts of dimethyl phthalate, 36 parts of azelaic acid, 2-methyl-
95 parts of 1,8-octanediol and 35 parts of hexamethylene glycol were heated together with 0.17 part of dibutyltin diacetate to remove by-produced methanol and water.
Thereafter, the reaction product was transferred to a reaction vessel capable of reducing the pressure, and reacted under reduced pressure to obtain a polyester (A ') having an intrinsic viscosity of 0.96. Polytetramethylene terephthalate (intrinsic viscosity 0.92) (polyester (B ')) obtained by polymerization in the same manner as the polyester (A') was 50% by weight of polyester (A ') and 5% by weight of polyester (B').
0% by weight, 1 mmHg at 250 ° C for 20 minutes
Under reduced pressure. The contents were cloudy at first, but became transparent from about 15 minutes. Twenty minutes later, 0.1 part of phenylphosphonic acid was added, and the mixture was stirred for another 5 minutes and then taken out. The intrinsic viscosity of this polyester block copolymer was 0.95.

The obtained polymer was discharged from a 12-hole die at 250 ° C. and wound at 400 m / min to obtain an elastic yarn. This elastic yarn has an elongation of 640% and a strength of 0.7 g / d.
e, the elastic recovery was 100%, as measured by immediate recovery after 50% elongation (1.5 times the original length). This yarn was immersed in an aqueous solution of sodium hypochlorite at a pH of 7 adjusted to a chlorine concentration of 600 ppm at 60 ° C. for 2 hours, but the strength hardly decreased. Light irradiation at 60 ° C. for 144 hours was carried out with a xenon tester, but there was almost no coloring and the strength was maintained at 75% or more.

[0031]

Examples 3 and 4 and Comparative Examples 1 and 2 Polyesters (A ') and (B') shown in Table 1 were melt-mixed in the same manner as in Example 1, and when the inside became transparent, phenylphosphonic acid was used. Was added to obtain a polyester block copolymer. Table 1 shows the properties of the obtained polymer and the elastic yarns composed of the polymer.

[0032]

[Table 1]

[0033]

Comparative Example 3 Dimethyl terephthalate 37.1 parts, tetramethylene glycol 23.9 parts, number average molecular weight 200
00.7 parts of polytetramethylene glycol and 0.03 parts of tetrabutyl titanate were charged into a reactor, and transesterification was carried out at an internal temperature of 190 ° C. And then to 3 mmHg over 30 minutes and then 24 hours at 245 ° C under a vacuum of 1 mmHg or less.
The reaction was performed for 0 minutes. This polymer was spun in the same manner as in Example 1 and treated, and the results are shown in Table 2.

[0034]

[Table 2]

Claims (1)

(57) [Claims] 1. A diol compound having a carbon number of 6 or more, wherein phthalic acids are the main acid component and the content of the diol compound represented by the following formula (I) is 50 mol% or more based on all glycol components. The polyester segment (A) as the component and the aromatic dicarboxylic acid component as the main acid components, and the aliphatic glycol having 2 to 4 carbon atoms as α, ω-diol and / or 1,4-cyclohexanedimethanol as the main glycol component. A polyester block copolymer comprising a polyester segment (B). HOCH ₂ RCH ₂ OH (I) (R represents a C 4-7 aliphatic saturated hydrocarbon residue having at least one branched methyl group)