JPS5839166B2 - Polyester - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing polyester.

More specifically, the present invention relates to a method for producing polyester having a low content of terminal carboxyl groups.

Conventionally, polyesters, especially polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6
- It is well known that aromatic polyesters such as naphthalene dicarboxylate are useful as molding materials for fibers, films, molded articles, etc.

For example, in the case of polyethylene terephthalate, the method for producing such polyester usually involves transesterification of ethylene glycol and dimethyl terephthalate, but it is also possible to react ethylene glycol and terephthalic acid or to carry out an addition reaction between ethylene oxide and terephthalic acid. A method is used in which bisglycol of terephthalic acid or a low polymer thereof is formed, and then the bisglycol ester or low polymer thereof is heated and polymerized in a molten state under reduced pressure.

In the above-mentioned polymerization reaction, the reaction proceeds even without a catalyst, but it is extremely slow, so a polymerization catalyst such as antimony trioxide, titanium tetraalkoxide, etc. is generally used to increase the speed of the polymerization reaction.

Also, the rate of this polymerization reaction is faster at high temperatures than at low temperatures, which is the same as in general esterification reactions or transesterification reactions, and the polymerization temperature is usually 250 to 300°C.
high temperature is used.

However, heating an organic compound at 250° C. or higher, especially near 300° C. for a long time cannot avoid thermal decomposition of reaction products and side reactions.

Since the synthesis of polyester is generally carried out at high temperatures as mentioned above, decomposition occurs constantly at the same time as polymerization, and at this time, the number of terminal carboxyl groups increases.

This tendency becomes more pronounced as the polymerization temperature increases. Therefore, even if the polymerization temperature is raised for the purpose of quickly obtaining a polyester with a high degree of polymerization, a decomposition reaction occurs significantly and a polyester with a high degree of polymerization cannot be obtained.

The present inventors have arrived at the present invention as a result of intensive research to produce a polyester with fewer terminal carboxyl groups.

That is, the present invention uses a polyester in a molten state with an intrinsic viscosity of 0.4 or more and a formula for the ratio of the polycarboxylic acid component to 0.1 to 1 mol % based on the total acid components constituting the polyester [however, the formula R1, R2, R3, R4, R, inside.

R6 and R7 are organic residues that do not have a hydrogen atom or an ester-forming functional group, and they may be the same or different (only when 7=1, R1 and R3゜R1 and R, R
1 and R5J R1 and R7 may be bonded to each other)
, and R8 is a monovalent organic residue having no ester-forming functional group.

l is 1 or 2, m, n, p, q and r are O
or 1, and m+n≧1.

This is a method for producing a highly polymerized polyester, which is characterized by reacting the polyester with an ester of at least one polycarboxylic acid selected from the group consisting of polycarboxylic acids represented by the above formula.

The polyester referred to in the present invention mainly refers to linear homopolyesters or copolyesters such as (1) polyesters composed of dicarboxylic acids and dihydroxy compounds, (2) polyesters composed of oxycarboxylic acids, but branched Examples of agents include glycerin, pentaerythritol, dipentaerythritol, sorbitol, butane-1,2,4-tricarboxylic acid, trimellitic acid, pyromellitic acid, 5-oxyisophthalic acid,
It may also be one obtained by copolymerizing a trifunctional or higher polyfunctional compound such as 2,4-dioxy-terephthalic acid or the like in such a proportion that the polymer is substantially linear.

The dicarboxylic acid component constituting the polyester in (1) above includes (a) aliphatic dicarboxylic acids such as succinic acid, pimelic acid, sepatic acid, decamethylene dicarboxylic acid, etc.; (b) cyclohexanedicarboxylic acid, biscyclohexyl-4 , 4-dicarboxylic acid, cyclobutanedicarboxylic acid,
Decalin-1,4-dicarboxylic acid, Decalin-2,6-
Alicyclic dicarboxylic acids such as dicarboxylic acids: () → Phthalic acid, isophthalic acid, terephthalic acid, methylterephthalic acid, methylisophthalic acid, naphthalene-2
, 6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, tetralin-
1,5 dicarboxylic acid, tetralin-2,6-dicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, biphenyl-3,4'-dicarboxylic acid, 1.2,3,4,5,6
-hexahydrobiphenyl-4,4'-dicarboxylic acid,
Aromatic dicarboxylic acids such as diphenylsulfone-4,4'-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, diphenylketone-4,4'-dicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, etc. Examples include acids.

In addition, dihydroxy compound components include (a) aliphatic glycols such as ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, etc.; (b) cyclohexane; Alicyclic glycols such as -1,4-diol, cyclohexane-1,4-dimetatool, decalin-2,6-dimetatool, etc.: ()→ Hydroquinone, bisphenol-Jl 4゜4'-dioxybiphenyl, 4,4 'Aromatic dioxy compounds such as dioxydiphenyl sulfone, 1,1-bis(p-oxyphenyl)cyclohexane, etc.) 1,4-bis(β-hydroxyethoxy)benzene, 4,4'-bis( Aliphatic glycols containing aromatic nuclei such as p-β-hydroxyethoxyphenyl)-sulfone, 2,2-bis(p-β-hydroxy-ethoxyphenyl)propane, etc.: (Polyethylene glycol, polypropylene glycol, polytetra Polyether glycols such as methylene glycol, polyhexamethylene glycol, etc. Also, as the oxycarboxylic acid component constituting the polyester in (2), (a) aliphatic acids such as ω-oxycaproic acid, ω-oxyundecic acid, etc. Oxycarboxylic acids: (b) Aromatic oxycarboxylic acids such as p-oxybenzoic acid, p-β-hydroxyethoxybenzoic acid, p-(p-β-hydroxyethoxy)phenyl-benzoic acid, etc. I can do it.

The above polyester can be produced by, for example, 1) reaction of dicarboxylic acid or its lower alkyl ester or aryl ester with a dioxy compound, 2) reaction of oxycarboxylic acid or its lower alkyl ester or aryl ester, 3) reaction of dicarboxylic acid or oxycarboxylic acid with ethylene. Reaction of a low polymer obtained by reaction with oxide or ethylene carbonate, 4) Reaction of dicarboxylic acid halide with dioxy compound, 5) Reaction of dicarboxylic acid with lower fatty acid ester of aromatic dioxy compound such as hydroquinone diacetate, etc. Manufactured by a conventionally known method.

In the present invention, particularly preferred polyesters are polyesters containing at least an aromatic nucleus in the molecule and having a melting point of 150°C or higher.

As mentioned above, such polyesters undergo decomposition at the same time as polymerization in the melt polymerization reaction, resulting in many terminal carboxyl groups. However, by applying the method of the present invention, it is possible to easily obtain a polyester with a small number of terminal carboxyl groups and high heat-and-moisture resistance. I can do it.

The polycarboxylic acid esters used in the present invention have the above formulas (1), (2), (3), (4).
, (5) and (6) are esters of polycarboxylic acids and hydroxy compounds.

R1 and R4 in the above formula are organic residues that do not have a hydrogen atom or an ester-forming functional group, and the organic residues include r
Or when q is 1, for example, methyl, ethyl, n-propyl, isopropyl, methoxyethyl, cyclohexylmethyl, benzyl, cyclohexyl, methylcyclohexylphenyl, p-1-IJ, 2,4-dichlorophenyl group When r or q is O, examples thereof include alkylidene groups such as ethylidene, propylidene, inpropylidene, butylidene, benzylidene groups and the like.

Furthermore, examples of R2 and R3 include the same hydrogen atom, alkyl, cycloalkyl, or aryl group as mentioned above for R1 and R4.

R,, R6, R7 are R1, R. It may be the same hydrogen atom, alkyl, cycloalkyl or aryl group.

Furthermore, when R1 and R2 are bonded, the group to which R1 and R2 are bonded includes, for example, an alkylene group such as trimethylene, tetramethylene, pentamethylene, 2,4-dimethylpentamethylene group, etc., and l= 1 and R1 and R3 are bonded, the group to which R1 and R3 are bonded includes, for example, an alkylene group such as ethylene, propylene, trimethylene group, etc., and when R1 and R4 are bonded, Examples of the group to which R1 and R4 are bonded include divalent hydrocarbon residues such as methylene, ethylidene, propylidene, and impropylidene;
When R2 and R5 are bonded, examples of the group bonded to R2 and R5 include methylene, ethylidene, ethylene, propylene,
Examples include divalent hydrocarbon residues such as 1,2-dimethylethylene and trimethylene groups, and when R1 and R7 are bonded, examples of groups where R1 and R7 are bonded include methylene, ethylidene, propylidene, Divalent hydrocarbon residues such as ethylene, propylene, trimethylene groups and the like may be mentioned.

Examples of R8 include methylene, ethylidene, propylidene, ethylene, propylene, 1,2-dimethylethylene, trimethylene, 2-methyltrimethylene, tetramethylene, hexamethylene, 1,4-cyclohexylene,
1,3-cyclohexylene, 1,4-phenylene, 2,
5-dimethyl-1,4-phenylene, 2-chloro-1,
Divalent organic residues such as 4-phenylene, 2,6-naphthylene, 1,5-naphthylene groups and the like can be mentioned.

Preferred examples of the polycarboxylic acids include R1, R
2, R3, R,, R,, the molecular weight of R6 and R7 is 100
Examples of polycarboxylic acids below and in which R8 has a molecular weight of 200 or less, and more preferable polycarboxylic acids include q=1 and R1
-The molecular weight of R7 is 100 or less and the molecular weight of R8 is 200
These include:

Specific examples of such polycarboxylic acids are illustrated below.

Particularly preferred polycarboxylic acids in the present invention are those in which 7=1 in formula (1): 1)
In formula (1), n = O polycarboxylic acid, 2X (
2) a polycarboxylic acid, 3) a polycarboxylic acid in which n=1 in formula (3), and a more preferred polycarboxylic acid is 1) a polycarboxylic acid in which n = O in formula (1).

Furthermore, as the hydroxy compound that forms the polycarboxylic acid ester, those having a molecular weight of 500 or less are usually used, such as methanol, ethanol, propatool, etc.
Monohydric aliphatic alcohols such as butanol, etc.; polyhydric aliphatic alcohols such as ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, etc.; benzyl alcohol, cyclohexane dimetatool, etc. Examples include monovalent and polyvalent aromatic oxy compounds such as alicyclics, aromatic alcohols, phenol, cresol, xylenol, propylphenol, butylphenol, and octylphenol.

Among these, polyhydric aliphatic alcohols with a molecular weight of 150 or less, aromatic oxy compounds with a molecular weight of 250 or less, and the like are particularly preferred.

When the hydroxy compound is a monohydric alcohol and/or phenol, the ester of polycarboxylic acid is a monomer (tetraester of tetracarboxylic acid, triester of tricarboxylic acid, diester of dicarboxylic acid, etc.)
However, in the case of polyhydric alcohols, the esters of polycarboxylic acids can be monomers, oligomers and/or polymers.

Preferred esters of such polycarboxylic acids are esters of polycarboxylic acids represented by formulas (1) to (6) above and polyhydric alcohols and/or phenols, particularly esters of monohydric phenols among phenols. It is.

A monohydric phenol ester of polycarboxylic acid is preferable because it has the effect of increasing the polymerization rate in addition to the effect of reducing the terminal carboxyl group of the polyester.

When the ester of the polycarboxylic acid represented by formulas (1) to (6) above is a polymer, it may be a homopolymer, or it may be a copolymer containing the polycarboxylic acid as part of the acid component. .

In this case, the copolymer can be produced using the carboxylic acid component and/or dihydroxy compound component used in producing the polyester referred to in the present invention.

The copolymerization ratio is not particularly limited, but it is preferable that the polycarboxylic acid represented by the above formula accounts for 50 mol% or more, preferably 70 mol% or more of the total acid component.

In the present invention, a small proportion of polycarboxylic acid esters represented by formulas (1) to (6) are added to a molten polyester having an intrinsic viscosity of 0.4 or more and reacted.

Here, a small proportion means that the amount of the polycarboxylic acid component in the ester of the polycarboxylic acid represented by the formulas (1) to (6) is 0 with respect to the total acid components constituting the polyester in a molten state.
, 1 to 1 mol%, particularly preferably 0.1 to 064 mol%
This is the ratio.

If the amount of the polycarboxylic acid component is too large, the amount of terminal carboxyl groups in the resulting polyester will be reduced, but this is not preferable because the hydrolytic stability will be poor.

The reaction temperature between the polyester and the polycarboxylic acid ester can be any temperature as long as the polyester can be kept in a molten state, but it is usually higher than the melting point of the polyester, and even 18
The temperature is preferably 0 to 320°C, particularly 240 to 300°C.

If the temperature is too low, the reaction rate will be slow, making it difficult to achieve the object of the present invention, and if the temperature is too high, the resulting polyester will become more discolored, which is not preferable.

The reaction time may be 1 minute or less, but is usually 1 minute or more and 10 hours, preferably 15 minutes or more and 8 hours, particularly preferably 30 minutes or more and 5 hours. 50% or more, preferably 70%
% or more is the time until it reacts with polyester and decomposes, under reduced pressure (for example, absolute pressure 10 = 0.1 mmHg
) is preferable.

In particular, it is preferable to add and react a polycarboxylic acid ester during the polyester polymerization reaction step.

According to the method of the present invention, a polyester having a low content of terminal carboxyl groups, particularly a high degree of polymerization polyester having a low content of terminal carboxyl groups and excellent hydrolytic stability, can be easily obtained.

In the present invention, the intrinsic viscosity of polyester is determined by dissolving the polyester in orthochlorophenol and measuring it at 35°C, and the amount of terminal carboxyl groups is determined by the method of A. Conix (A, Con1x) (Makr.
o mol, Chem, 26, 226 (195
8)).

Next, the present invention will be explained in detail using actual cases.

Note that "parts" in actual cases mean "parts by weight."

Examples 1-14 97 parts of dimethyl terephthalate, 6 parts of ethylene glycol
9 parts of antimony trioxide, 0.04 parts of calcium acetate hydrate, and 0.07 parts of calcium acetate hydrate were charged into a rectification column and an autoclave with a stirrer, and heated to 160 to 225°C to distill out methanol produced as a result of the transesterification reaction. I let it happen.

After the transesterification reaction was completed, the same mole of ring phosphoric acid was added to calcium acetate, and the transesterified product was transferred to a polymerization reactor, and the internal temperature was raised to 265°C over 30 minutes in a nitrogen stream, and then The internal temperature was raised to 275° C. over a period of minutes, and during this time the pressure of the reaction system was gradually reduced to an absolute pressure of 0.3 mmHg.

Subsequently, at 275°C and under reduced pressure of 0.3 miHg absolute pressure,
Polymerization was carried out for 0 minutes to obtain a polymer having an intrinsic viscosity of 0.5.

Here, the pressure of the reaction system was returned to normal pressure with nitrogen gas, and 0.2 to 0.3 mol% of the various polycarboxylic acid esters of the method of the present invention were added to the total acid components constituting the polyester. After stirring for a minute, the absolute pressure was increased to 0.3 mmH again.
Polymerization was carried out for 30 minutes at a reduced pressure of 1.3 g.

Table 1 shows the intrinsic viscosity, terminal carboxyl group content, etc. of the obtained polyester.

Comparative Examples 1 to 4 Comparisons were carried out in exactly the same manner as in Example 1 except that a conventionally known additive was used instead of the polyarylester of polycarboxylic acid.

The results obtained are shown in Table 2. Actual cases 15-28 83 parts of terephthalic acid, 69 parts of ethylene glycol, and 0.05 parts of manganese acetate are placed in a rectification column and an autoclave with a stirrer, and heated to 240°C under nitrogen pressure to produce water as a result of the esterification reaction. was distilled out.

After the esterification reaction was completed, trimethyl phosphate was added in 1.3 times the mole of manganese acetate, followed by 0.04 parts of antimony trioxide, and the esterification reaction product was transferred to a polymerization pot for 30 minutes in a nitrogen stream. and the internal temperature to 265
℃, then take 30 minutes to bring the internal temperature to 275℃.
During this time, the pressure of the reaction system was gradually reduced to 0.3 m.
It was set as mHg.

Continued at 275°G and 60°C under reduced pressure of 0.3 miHg.
Polymerization was carried out for a minute to obtain a polymer having an intrinsic viscosity of about 0.5.

Here, the pressure of the reaction system was returned to normal pressure with nitrogen gas, and 0.2 to 0.3 mol% of esters of various polycarboxylic acids shown in Table 3 were added to the total acid component that intercepts the polyester, After stirring for 2 minutes at normal pressure, the mixture was stirred again under reduced pressure of 0.3 mπHg.
Polymerization was carried out for 00 minutes.

The intrinsic viscosity and terminal carboxyl group content of the obtained polyester are shown in Table 3.

Here, in the synthesis of polycarboxylic acid ester, a dihydroxy compound is added to the polymethyl ester of the corresponding polycarboxylic acid at a ratio of 1.1 to the ester group in the polycarboxylic acid.
Add twice the mole and 0.02 mol% of manganese acetate to 150
The transesterification reaction was carried out by heating to ~180°C, and then a portion of the dihydroxy compound was removed from the reaction system under reduced pressure.

The amount of polycarboxylic acid ester to be added to polyethylene terephthalate can be determined by hydrolyzing a portion of the obtained polycarboxylic acid ester with an aqueous solution of caustic soda and then titrating with acid to determine the amount of the polycarboxylic acid component in the polycarboxylic acid ester. I went to find the content.

Comparative Examples 5 to 8 Comparative examples 5 to 8 were carried out in exactly the same manner as in Actual Case 15, except that conventionally known additives were used instead of polycarboxylic acid esters, and the additives were synthesized in the same manner as Actual Case 15.

The results obtained are shown in Table 4. Example 29 and Comparative Example 9 115 parts of dimethyl sebacate, 118 parts of hexamethylene glycol, and 0.04 parts of tetrabutyl titanate were charged into a rectification column and an autoclave with a stirrer, and 170 to 2
The methanol produced as a result of the transesterification reaction was distilled off by heating to 20°C.

Then, transfer the transesterified product to a polymerization kettle and add 270% of bath salt.
℃ and gradually reduce the pressure in the reaction system to an absolute pressure of 0.1
Polymerization was carried out for 60 minutes under mmHg to obtain a polymer having an intrinsic viscosity of 0.52.

Here, the pressure of the reaction system was brought to normal pressure with nitrogen gas, 0.76 part of triphenyl ester (0.3 mol% based on the total acid components constituting the polyester) was added, and the reaction system was again brought to absolute pressure. Polymerization was carried out for 30 minutes under reduced pressure of 0.1 mmHg.

The intrinsic viscosity of the obtained polyester was 0.935. The amount of terminal carboxyl groups was 40 g equivalent/106 g.

For comparison, the same procedure as in Example 29 was carried out, except that the triphenyl ester in (1) was not used and the polymerization reaction was carried out under reduced pressure of 0.1 mmHg absolute pressure for 90 minutes.

The resulting polyester had an intrinsic viscosity of 0.73° and a terminal carboxyl group weight of 18 equivalents/106 g.

Example 30 and Comparative Example 10 98 parts of methyl β-cedroxyethoxybenzoate, 34 parts of ethylene glycol, and 0.02 parts of tetrapropyl titanate were charged into a rectification column and an autoclave with a stirrer, and the mixture was heated to 160 to 225°C for transesterification. Methanol produced as a result of the reaction was distilled off.

The transesterified product was then transferred to a polymerization kettle, and the bath was heated to 285°C.
The pressure in the reaction system was gradually reduced to an absolute pressure of 0.2 mm.
Polymerization was carried out for 600 minutes under Hg to obtain a polymer with an intrinsic viscosity of 0.42.

Here, the pressure of the reaction system was brought to normal pressure with nitrogen gas, 2 parts of 0% tetraphenyl ester (0.4 mol% based on the total acid components constituting the polyester) was added, and the reaction system was again brought to the absolute pressure. Polymerization was carried out for 120 minutes under reduced pressure of 0.2 mmHg.

The intrinsic viscosity of the obtained polyester was 0.73. The amount of terminal carboxyl groups was 3.5 equivalents/10'g.

For comparison, the polymerization reaction was carried out at reduced pressure of 0.2 mrrtHg without using 0 tetraphenyl ester.
The same procedure as in Example 30 was conducted except that the test was carried out for 0 minutes.

The intrinsic viscosity of the obtained polyester was 0.48, and the amount of condensed carboxyl groups was 16.0 equivalents/10'! It was i2.

Example 31 and Comparative Example 11 A reaction was carried out in the same manner as in Example 1 using 97 parts of dimethyl terephthalate, 144 parts of cyclohexanedimethanol (1,4), and 0.007 parts of titanium tetraisopropyl oxide.

Next, the transesterified product was transferred to a polymerization reactor, and the internal temperature was set at 285°C, and the pressure of the reaction system was gradually reduced to an absolute pressure of 0.3 ii
Polymerization was performed under Hg for 60 minutes, and the intrinsic viscosity was 0.52. A polymer having a terminal carboxyl group weight of 20.2 equivalents/106 g was obtained.

Here, the pressure of the reaction system was brought to normal pressure with nitrogen gas, 1.38 parts of 0% tetraphenyl ester was added, and the reaction system was again reduced to an absolute pressure of 0.3 iiHg and polymerized for 30 minutes.

The intrinsic viscosity of the obtained polyester was 0.92. The amount of terminal carboxyl groups was 9.2 equivalents/106 g.

For comparison, the same procedure as in Example 31 was carried out, except that 0 tetraphenyl ester was not used and the polymerization reaction was carried out under reduced pressure of 0.3 mπHg absolute pressure for 90 minutes.

The resulting polyester had an intrinsic viscosity of 0.65° and a terminal carboxyl group weight of 25.8 equivalents/106 g.

Comparative Example 12 The addition of 0 tetraphenyl ester in Example 6 was carried out at the start of the transesterification reaction, and the absolute pressure was 0.3 mmHg.
The same procedure as in Example 6 was conducted except that the polymerization time under reduced pressure was changed to 90 minutes.

The intrinsic viscosity of the obtained polyester was 0.75. The amount of terminal carboxyl groups was 1 g equivalent/10'g.

Claims (1)

[Scope of Claims] 1 A formula for the ratio of a polyester in a molten state with an intrinsic viscosity of 0.4 or more and a polycarboxylic acid component of 0.1 to 1 mol % based on the total acid components constituting the polyester [However, , R1, R2, R3, R4, R, in the formula. Hiki and R7 are organic residues that do not have a hydrogen atom or an ester-forming functional group, and these may be the same or different.
Note that only in the case of 7=1, R1 and R3゜R1 and R4, R1
and R, R1 and H may be bonded to each other), and R3 is a divalent organic residue having no ester-forming functional group. l is 1 or 2, m, n, p, q and r are O
or 1, and m-1-n≧1. A method for producing a highly polymerized polyester, which comprises reacting with an ester of at least one polycarboxylic acid selected from the group consisting of the polycarboxylic acids represented by the following.