JPS591290B2 - Polyester Noseizouhouhou - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for producing polyester, particularly polybutylene terephthalate (hereinafter referred to as "PBT").
The present invention relates to a method for producing a copolymer.

PBT is used in many fields such as mechanical parts and electrical parts due to its excellent physical properties and processability, but depending on the application, it is often required to further improve specific physical properties.

Physical properties that require improvement include impact resistance, transparency, and flame retardancy. Generally, the physical properties of polymers are improved by adding fillers, auxiliary agents, etc., blending them with other polymers, or copolymerizing them with different monomers.

Addition of fillers, auxiliary agents, etc. not only has the possibility of reducing the excellent physical properties originally possessed by the polymer, but also poses problems such as elution of fillers and auxiliary agents from the polymer. is not very desirable as it causes environmental problems.

However, despite these disadvantages, it is most commonly used industrially because desired physical properties can be improved very easily. Furthermore, when blending with other polymers, it is necessary to select polymers that have good compatibility with each other, so it is difficult to improve the desired physical properties while satisfying this restriction.

On the other hand, the method of improving the physical properties of a polymer by copolymerization with a different type of monomer does not have the disadvantages mentioned above and is the most desirable method, but it is difficult to produce such a copolymer depending on the monomer. There are major drawbacks in this respect.

For example, PBT is 1,4-butanediol (hereinafter referred to as “1
・4BG") and terephthalic acid (hereinafter referred to as "TPA")
) or its alkyl ester, and the molar ratio of 1.4BG to TPA or its alkyl ester is 1.05.
By esterifying or transesterifying the above, bis(ω-hydroxybutyl) terephthalate or its low polymer (hereinafter referred to as "BHBT") is obtained, and this BHBT
However, when 1.4BG and a diol represented by the general formula are copolymerized together as a diol, the degree of polymerization is high enough to be practically applicable. For example, only [η] of 0.5 can be obtained.

Of course, if a copolymer having an extremely low content of diol represented by the above general formula is also produced, the degree of polymerization will be improved, but the desired improvement in physical properties cannot be expected. The reason for this is probably that the diol represented by the above general formula, although difunctional, has poor polymerization reactivity and acts as an end-sealing agent to stop the polymerization reaction. The present inventors conducted extensive research on a method for producing PBT using the diol represented by the general formula shown above as a copolymerization component, and found that first, the diol represented by the general formula shown above was reacted with TPA or an alkyl ester thereof, and then, The inventors have now discovered that PBT having a high degree of polymerization and a relatively high content of the diol component represented by the above general formula can be obtained by reacting it with 1.4BG and then performing polycondensation, thereby achieving the present invention.

That is, the present invention is based on the general formula (wherein R is an alkylene group having 1 to 6 carbon atoms,
7 cycloalkylene group, -0-, -S-SO2-, or -NZ- (Z is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms): A, . B represents an aromatic nucleus which may be substituted with a halogen atom: X and Y are FO-(CH2)l
+m (l represents a number from 1 to 4, m represents a number from 1 to 10, X and Y may be the same or different) and terephthalic acid or its alkyl ester, The molar ratio of the diol component to terephthalic acid or its alkyl ester is less than 1.0, and after reacting until the esterification rate for the hydroxyl group of the diol is 70% or more, A method for producing a polyester is characterized in that 1,4-butanediol is added and reacted so that the molar ratio is 1.05 or more, and the resulting reaction product is polycondensed.

The present invention will be explained in more detail below.

In the present invention, first, in the general formula, R is an alkylene group having 1 to 6 carbon atoms, a cycloalkylene group having 5 to 7 carbon atoms, -0-, -S-, -SO2- or -NZ- (Z is hydrogen A, . B represents an aromatic nucleus which may be substituted with a halogen atom; X and Y are {0-(CH2)l+Rr)
(1 indicates a number from 1 to 4, m indicates a number from 1 to 10,
and Y may be the same or different).

A diol component containing at least a portion of the diol represented by is reacted with TPA or an alkyl ester thereof such as dimethyl terephthalate.

Among the diols represented by the above general formula, those in which R is -Cno01 or -SO2-, l-2 to 4, and m = 2 to 5 are preferred from the viewpoint of availability or effectiveness.

Compounds represented by formula I or HObe(8)XRbe8Xx 0H, which are similar to the diols represented by the general formula shown above, cannot be used because they have extremely poor reactivity with TPA.

Next, Table 1 lists specific examples of diols represented by the above general formula.

Of course, these diols may be a mixture. The use of the above monomers makes it possible to obtain transparent polybutylene terephthalate.

Among the diols represented by the above general formula, those in which aromatic nuclei A and B are substituted with halogen atoms such as fluorine, chlorine, and bromine impart flame retardancy to the final polymer. In particular, those that provide excellent flame retardancy are those substituted with bromine atoms, and those that are substituted at the 3rd and 5th positions of the aromatic nucleus.

Next, Table 2 lists bromine compounds as specific examples of diols represented by the above general formula substituted with halogen atoms.

In the present invention, the first reaction may be carried out by reacting the diol represented by the above general formula alone with TPA or an alkyl ester thereof, or by reacting a mixture of the diol represented by the above general formula with another diol, such as 1.4BG. You may make it react with the diol component consisting of TPA or its alkyl ester.

In any case, it is necessary that this reaction be carried out at a molar ratio of diol component to terephthalic acid of less than 1.0.

Preferably it ranges from 0.1 to 0.8, optimally from 0.2 to 0.6. If the molar ratio is 1 or more, the object of the present invention cannot be achieved.

That is, it becomes impossible to obtain a polymer with a high degree of polymerization that can be put to practical use. The diol represented by the above general formula differs depending on its type and the degree of improvement in physical properties expected, but it usually accounts for 4 to 70 mol%, particularly 5 to 60 mol%, of the diol component in the PBT main chain. is desired.

However, in the case of a halogen-substituted diol represented by the general formula shown above, it is desirable that the content be 4 to 50 mol%, particularly 5 to 30 mol%, and most preferably 5 to 20 mol%. Therefore, the molar ratio of the diol represented by the above general formula to TPA or its alkyl ester is 0.04 to 0.7, particularly 0.05.
It is preferable to use ˜0.6.

On the other hand, among the diols represented by the above general formula, those whose aromatic nucleus is substituted with a halogen atom have a molar ratio of 0.04 to 2 to TPA or its alkyl ester.
0.5, especially 0.05 to 0.3, most preferably 0.05 to 0.
It is preferable to use 2. It goes without saying that when 1.4BG is used in combination, the amount used must be such that the sum of 1.4BG and the diol represented by the general formula shown above satisfies the above-mentioned requirements.

The conditions for this reaction are no different from the well-known BHBT production conditions; for example, in the case of the direct esterification method, 150 to 2
80℃, 10T0rr~10atm, especially 100T0r
r ~ 5 atm, or transesterification method in this case 150 ~ 2
30℃, 10T0rr to 3 atmospheres, especially 100T0rr
~Performed under normal pressure conditions.

Of course, a catalyst may be used, and various known catalysts for producing PBT can be used, but Ti-containing compounds are preferred. Examples of Ti-based catalysts include tetraalkoxytitanium represented by Ti(0R)4 (i.e., te*7traalkyl titanate) and tetrahydroxytitanium (R is H.CH3, n-C3
H7, IsOC3H7, n-C4H, ISO-C4H
9, SecC4H,,Tert-C4H9,n-C5H
llXnC6Hl3) ISO-C8H7) C6H5-
);TiCl(0C2H5)3.HCl;(RO)3T
Examples include inorganic titanium compounds such as i-0Ti(0R)3; titanate represented by TiO(0R)2; K2TiF6. This reaction needs to be carried out to an esterification rate of 70% or more, particularly 80% or more with respect to the hydroxyl group of the diol. In the present invention, the esterification rate of hydroxyl groups of diol is also expressed as the ratio of esterified hydroxyl groups to the total hydroxyl groups of diol. Next, in the present invention, 1.4BG is added so that the molar ratio of the diol component to TPA or its alkyl ester is 1.05 or more, particularly 1.1 to 1.6.

Then, the reaction is further continued, using the reaction conditions as described above, until the esterification rate of carboxyl groups is 80% or more, particularly 90% or more.

Here, the esterification rate for carboxyl groups is also expressed as the ratio of carboxyl groups esterified with diol to the total carboxyl groups.

The reaction product thus obtained is bis(ω-hydroxybutyl terephthalate) or a low polymer with a degree of polymerization of 20 or less, particularly 10 or less, and is subjected to polycondensation. Polycondensation can be carried out by various well-known methods, and usually 22
It is carried out at a temperature of 0 to 280°C and a reduced pressure of 0.01 to 10T0rr.

As explained above in detail, the present invention involves first reacting a diol represented by the general formula shown above with poor polymerization reactivity under conditions in which TPA or an alkyl ester thereof is in excess.
The present invention provides a method for producing a useful PBT copolymer with a high degree of polymerization by preventing the action of the terminal sealing agent of the diol represented by the general formula.

Hereinafter, the present invention will be explained in further detail with reference to Examples.

Example 1 Dimethyl terephthalene 97y (0.5mol),
2.2'-(3'.5'-dibromo4'-hydroxyethoxyphenyl)propane (BA-50TM'' manufactured by Gray Lakes) 14.6 V (
0.023 mol), 1.4 BG2
o. 5y (0.227mol), 1 vol. tetrabutyl titanium catalyst (0.6% 1.4BG solution with Ti) 1
．． 7 ml (120 ppm of Ti per 1 volume of dimethyl terephthalene) was placed in a polymerization reactor and placed in a foil bath heated to 16°C to carry out the reaction at normal pressure. After approximately 5 minutes, the system became transparent and the reaction continued for 25 minutes. The temperature was then raised to 200°C for 30 minutes, and the temperature was maintained at 200°C for 30 minutes.

(The esterification rate for the hydroxyl group of the diol was 85%) Therefore, 4 o. 6 y (0.4 51 mol) of 1.
Add 4BG, hold at 200°C for 30 minutes, raise the temperature to 210°C, and react for 1 hour. (Total esterification reaction time: 3.0 hours) The esterification rate for carboxyl groups at this time was 92%.

Next, the temperature of this reaction product was increased to 245°C in 1 hour, and at the same time the pressure was reduced to 1 Torr or less, and after the 1st hour, the temperature was maintained at 245°C, and the pressure was also reduced to 0.5°C after 1.5 hours. 0 5 Torr, maintain this pressure from now on,
A polycondensation reaction was carried out.

The reaction was stopped 4.0 hours after the start of pressure reduction. [η] of the obtained polymer = 0.9 4, terminal [COO
H]=18eq/106V. Furthermore, the polymer is transparent when cooled rapidly, but becomes white crystallized when cooled slowly.

No browning due to thermal decomposition of 2.2'-(3'.5'=dibromo4'=hydroxyethoxyphenyl)propane was observed, and the color tone was also good.

Example 2 TPA 3 3.2 5 y (0.2 0 mol
), 2 ・2'-(4'-hydroxyethoxyphenyl)propane (Nippon Nyukazai Co., Ltd. "New Coal 1900'
') 3 2.5 y (0.10 mol), tetrabutoxytitanium catalyst (0.6% 1·4BG solution in Ti)
Pour 0.7ml into a polymerization tank and after replacing with N2, reduce the system pressure to 5.
It was maintained at 0 0 Torr and placed in a 260°C oil bath for reaction.

After 3 hours, the system internal pressure was returned to normal pressure.

(Esterification rate of diol hydroxyl group: 83%) Next, 16.2 y (0.18 mol) of 1.4BG
was added and reacted for 30 minutes.

(Esterification rate for carboxyl groups: 93%) Next, 0.7 ml of tetrabutoxytitanium catalyst was added, the temperature was lowered to 245° C. in 10 minutes, and polymerization was carried out according to the reduced pressure schedule shown in Example 1.

The reaction was stopped 4.0 hours after the start of polymerization.

[η] of the obtained polymer was 0.6. Comparative example
1 TPA33.25V) 2.2'-(4'-hydroxyphenyl)propane3 2.5 y) 1.4 BG
16.27, 0.7 ml of tetrabutoxytitanium catalyst was charged into a polymerization reactor, and the reaction was carried out at 500 T0 rr at 1260° C. for 3.5 hours. Polymerization was carried out in the same manner as in Example 2, and the reaction was stopped after 4 hours of polymerization.

[η] of the obtained polymer was −0.18.

Claims (1)

[Claims] 1 General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R is an alkylene group having 1 to 6 carbon atoms, 5 to 6 carbon atoms
7 cycloalkylene group, -O-, -S-, -SO_2
-, or -NZ- (Z is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms); A and B represent an aromatic nucleus which may be substituted with a halogen atom; X and Y are ■O- (CH_
2) A diol component represented by __l■m (l represents a number from 1 to 4, m represents a number from 1 to 10, and X and Y may be the same or different) and terephthalic acid or its After reacting the alkyl ester until the molar ratio of the diol component to terephthalic acid or its alkyl ester is less than 1.0 and the esterification rate to the hydroxyl group of the diol is 70% or more, 1. A method for producing polyester, which comprises adding 1,4-ptadiol to the alkyl ester and causing the reaction so that the molar ratio to the alkyl ester is 1.05 or more, and polycondensing the resulting reaction product.