JPH0224292B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing polyesters, particularly polyesters using aliphatic glycols as the glycol component. The aim is to improve the polymerization rate. Traditionally, polyesters that use tetramethylene glycol, for example, differ from the current general-purpose polyethylene terephthalate in that tetramethylene glycol tends to decompose (cyclodehydrate) into tetrahydrofuran, and how to suppress this has become a major manufacturing issue. Ta. For this reason, titanium compounds and tin compounds, which are active at relatively low temperatures, are generally used as reaction catalysts. However, although the boiling point of the glycol to be distilled off during the reaction is high, it is polymerized at a low temperature, so even if decomposition is suppressed, the polycondensation reaction rate is slow and productivity is low. The inventor of the present invention has kept this point in mind and, as a result of intensive studies to increase the reaction rate, has discovered that the problem can be solved by adding a specific substance to the titanium compound, and has thus arrived at the present invention. That is, the present invention involves a polycondensation reaction when producing a polyester by reacting a difunctional carboxylic acid mainly consisting of an aromatic dicarboxylic acid or a lower alkyl ester thereof with a diol compound mainly consisting of an aliphatic glycol. [A]: Titanium compound and [B]: Hydrazine compound or its salt represented by the following general formula () R-NHNH ₂ ... () (However, R is hydrogen or a phenyl group which may have a substituent) This is a method for producing polyester, characterized in that it is carried out in the presence of. The polyester targeted in the present invention has an aromatic dicarboxylic acid as the main acid component and an aliphatic glycol as the main glycol component. Here, "mainly" means more than 50 mol%. Therefore, less than 50 mol% of other components may be contained. In the present invention, "aromatic dicarboxylic acid" refers to
These are compounds in which a carboxylic acid is directly bonded to an aromatic nucleus, such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyl etherdicarboxylic acid, and terephthalic acid is particularly preferred. In the present invention, "aliphatic glycol" refers to
ethylene glycol, trimethylene glycol,
It refers to tetramethylene glycol, hexamethylene glycol, neopentyl glycol, etc. Among these, particularly remarkable effects are observed when using tetramethylene glycol and hexamethylene glycol. Examples of the third component (less than 50 mol%) that can be copolymerized in the present invention include oxalic acid, malonic acid,
Aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and dodecanedioic acid; alicyclic dicarboxylic acids such as hexahydroterephthalic acid, decalindicarboxylic acid, and tetralindicarboxylic acid; oxyacids such as glycolic acid and p-oxybenzoic acid ; Aliphatic diols other than the main constituents of the polyester, such as ethylene glycol, trimethylene glycol, propylene glycol, 1,3-butanediol, neopentyl glycol; cyclohexanedimethanol, Examples include alicyclic diols such as tricyclodecane dimethylol; aromatic diols such as bisphenol A, bisphenol S, bishydroxyethoxybisphenol A, and tetrabromobisphenol A. In addition, within the range where the polyester can be considered to be substantially linear, polyfunctional compounds such as trimellitic acid, trimesic acid, pyromellitic acid, tricarballylic acid, trimethylolpropane, glycerin, pentaerythritol, benzoic acid, naphthoic acid, stearyl alcohol, etc. , a monofunctional compound such as palmitic acid may be added. In addition, like normal polyester, heat stabilizers such as phosphorus, antioxidants such as hindered phenol, ultraviolet absorbers such as benzotriazole, hydroxybenzophenone, cyanoacrylate, titanium oxide, carbon black, terrasol blue, etc. There is no problem even if pigments, dyes, nucleating agents such as talc, crystal accelerators such as higher fatty acid salts, mold release agents, etc. are added. The titanium compound used in the present invention has the general formula

[Formula] MTi (OR) ₆ , M [HTi (OR) ₆ ] ₂ (where R, R ₁ , R ₂ , R ₃ , R ₄ are alkyl groups,
aryl group, hydrogen and M represents an alkaline earth metal), their hydrolysates (including partial hydrolysates), transesterified products,
Hydrolysis and transesterification are carried out simultaneously, specifically, for example, tetrabutyl titanate, tetraisopropyl titanate, tetra(2
-ethylhexyl) titanate, tetrastearyl titanate, di-isopropoxy bis(acetylacetonato) titanium, di-n-butoxy
Bis(triethanolaminate) titanium, dihydroxy bis(lactate) titanium, titanium-isopropoxyoctylene glycolate, isopropoxytitanium-tri-isostearate,
Tetrabenzoic acid titanate; magnesium titanium methylate, magnesium titanium butyrate, magnesium titanium octylate, calcium titanium butyrate, strontium titanium ethylate, etc., and also with the general formula Ti ₂ (C ₂ O ₄ ) ₃ , (M) _o Ti ( C ₂ O ₄ ) ₂ ,
(M) _o OTi(C ₂ O ₄ ) ₂ (here M represents a metal atom, H, NH ₄ , n
is 1 when M is a divalent metal, M is H, NH ₄ and 1
In the case of valent metals, compounds represented by 2), such as titanium oxalate, potassium dioxalate titanate (), ammonium dioxalate titanate (), hydrogen oxodioxalate titanate (), and titanium oxodioxalate Examples include, but are not limited to, sodium oxodioxalate titanate ()ate, barium oxodioxalate titanate ()ate, calcium trioxalate titanate ()ate, and hydrates thereof. In the present invention, together with the titanium compound,
A hydrazine compound represented by the following general formula () or a salt thereof is used. R-NHNH ₂ ...() (However, R is hydrogen or a phenyl group which may have a substituent) Such hydrazine compounds include hydrazine,
Examples include phenylhydrazine, tolylhydrazine, hydrazineanisole, p-hydrazinobenzoic acid, and salts thereof include inorganic acid salts such as hydrochloride, sulfate, and hydrobromide, acetate, and tartaric acid. Examples include organic acid salts such as salts. When a hydrazine compound is used together with a titanium compound, the reaction rate is significantly improved, although the reason is not clear. Incidentally, when only the hydrazine compound is used without the titanium compound, the reaction does not proceed at all.
It is completely unexpected and surprising that the reaction rate is improved by using these compounds in combination. The amount of these compounds added varies depending on the purpose and is not particularly limited, but is generally 0.001 to 0.5 mol%, preferably 0.005 to 0.1 mol%, based on the total acid components of the polyester. Polyesters containing aliphatic glycol as the main glycol component are generally produced by direct esterification of aromatic dicarboxylic acids and glycols, or by transesterification of lower alkyl esters of aromatic dicarboxylic acids with glycols, etc. There is. In the former case by direct esterification,
The esterification reaction proceeds without a catalyst, but in this case, a titanium compound and a hydrazine compound may be added to the oligomer after the esterification reaction to perform the polymerization reaction, or both may be added during the esterification reaction. You can leave it there. In addition, in the case of the latter transesterification reaction, it is preferable to add both at the beginning of the reaction. In addition, if a reaction mixture of a titanium compound and a hydrazine compound is added,
The effect of improving the reaction rate is small, and even if the hydrazine compound is added at a different time from the titanium compound (for example, the titanium compound is added during the esterification or transesterification reaction, and the hydrazine compound is added during the polymerization reaction), the effect is also small. Therefore, it is preferable to add the two separately at relatively close times (of course, they may be added at the same time). The present invention will be specifically explained below using Examples. In the examples, "parts" indicate parts by weight, and the intrinsic viscosity of the polymer is the temperature of the orthochlorophenol solution at 35°C.
It is calculated from the solution viscosity at . Examples 1 to 10, Comparative Examples 1 to 5 97.1 parts of dimethyl terephthalate and 67.6 parts of tetramethylene glycol were charged, a titanium compound and a hydrazine compound were added in a predetermined amount and at a predetermined time, and transesterification reaction (EI) was carried out at an internal temperature of 170°C. was carried out.
After a predetermined amount of methanol has been distilled off, the internal temperature is reduced to 245℃.
After 30 minutes at 30 mmHg, the system was reduced to a vacuum of 0.5
Polymerization was carried out for a predetermined time under a high vacuum of mmHg. The reaction steps and polymer quality are shown in Table 1.

【table】

[Table] In each of the Examples in which the reaction was carried out in the presence of a titanium compound and a hydrazine compound, a remarkable improvement in the polymerization rate was observed, but when only a hydrazine compound was present (Comparative Example 1), only a titanium compound (Comparative Example 2) or when a reaction product of a hydrazine compound and a titanium compound was present (Comparative Example 3), no improvement in the polymerization rate was observed. In Table 1, Example 9 uses 122.1 parts of dimethyl-2,6-naphthalene dicarboxylate instead of 97.1 parts of dimethyl terephthalate in Example 1, and the polymerization temperature is changed to 245°C.
These are the results of a reaction conducted in the same manner as in Example 1 except that the reaction was carried out at 260°C. In Example 9, when hydrazine sulfate was not used, the intrinsic viscosity of the polymer increased only to 0.750 after 70 minutes of high vacuum reaction (Comparative Example 4). Further, Example 10 is the result of a reaction conducted in the same manner as in Example 1, except that 88.9 parts of hexamethylene glycol was used instead of 67.6 parts of tetramethylene glycol. In Example 10, when hydrazine sulfate was not used, the intrinsic viscosity of the polymer increased only to 0.800 after 70 minutes of high vacuum reaction (Comparative Example 5). Example 11 97.1 parts of dimethyl terephthalate, 62.1 parts of ethylene glycol, 0.0142 parts of titanium acetate, 0.0065 parts of hydrazine sulfate, and 0.0025 parts of cobalt acetate were charged into a reactor, and the temperature was raised to perform a transesterification reaction.
At the point when almost the theoretical amount of methanol had finished coming out (40 c.c. of methanol, the internal temperature at this time was 235°C), 0.0098 part of orthophosphoric acid was added, the system was reduced to vacuum, and 30 mm
After carrying out the reaction for 20 minutes in a weak vacuum of Hg, the contents were
The temperature was raised to ℃ and the reaction was carried out for 60 minutes under high vacuum of 0.5 mmHg. The intrinsic viscosity of the obtained polymer was 0.70. For comparison, when the reaction was carried out without adding hydrazine sulfate, the intrinsic viscosity of the polymer was only 0.64 even after 65 minutes of high vacuum time.

Claims (1)

[Scope of Claims] 1. When producing a polyester by reacting a difunctional carboxylic acid mainly consisting of an aromatic dicarboxylic acid or a lower alkyl ester thereof with a diol compound mainly consisting of an aliphatic glycol, a polycondensation reaction is not carried out. , [A]: titanium compound and [B]: hydrazine compound or its salt represented by the following general formula () R-NHNH ₂ ... () (However, R is hydrogen or a phenyl group which may have a substituent. ) A method for producing polyester, characterized in that it is carried out in the presence of. 2. The method according to claim 1, wherein the aromatic dicarboxylic acid is terephthalic acid. 3. The method according to claim 1 or 2, wherein the aliphatic glycol is tetramethylene glycol. 4. The method according to claim 1, 2 or 3, wherein the titanium compound is a tetraalkyl titanate.