JP3064057B2 - Method for producing polyester containing urethane bond - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a polyester containing a urethane bond which is useful for forming films, fibers, and other molded products, has sufficient strength for practical use, has a high melting point, and uses very little catalyst. It relates to a manufacturing method.

[0002]

BACKGROUND OF THE INVENTION Aliphatic saturated polyesters are:
In general, the melting point is low, most of which are 70 ° C. or less, and even if the number average molecular weight is in the high molecular range of 10,000 or more, a polyester containing a saturated aromatic structure, such as polyethylene terephthalate, has sufficient mechanical properties for practical use. It has not been practical until now because it does not show physical properties. In fact, even when the film has a film forming property, the produced film has low tear strength and tensile strength and is not practical. Among these, aliphatic polyesters containing 1,4-butanediol as a glycol component are:
It has been found that a polyester having a relatively high strength and capable of producing a film-forming polyester, though not having sufficient strength, can be produced by esterification with an aliphatic dicarboxylic acid such as adipic acid, sebacic acid or dodecanoic acid. In particular, in the case of an aliphatic polyester produced using succinic acid as a dicarboxylic acid, the melting point is as high as 110 to 115 ° C,
This is unique in that most aliphatic polyesters have a melting point below 70 ° C. However, 1,
Aliphatic polyester produced using 4-butanediol and succinic acid is crystalline, and undergoes a normal esterification and deglycolization reaction to have a number average molecular weight of 10,000 to
Even at 15,000, a fragile tendency is observed. This fragility can be improved by using other dicarboxylic acids such as adipic acid, sebacic acid, dodecanoic acid and the like, but there is still a problem in providing a practically usable film strength. As the number of methylene bonds between the carboxyl groups increases, the flexibility increases, but the melting point decreases.

Conventionally, in order to produce a high molecular weight polyester, for example, in the case of polyethylene terephthalate, an organic alkoxy compound of a heavy metal such as titanium, zinc, manganese, iron, lead and antimony, and a metal salt of an organic acid are deglycolized. It is known to be used as a catalyst for reactions. If these catalysts are used in a sufficient amount, it may be possible to increase the molecular weight to the required molecular weight in a short time, and if so, there is no problem, but for example, the obtained polyester is used as a food-related packaging material In such a case, it is desired that the amount of these catalysts used is as small as possible.

[0004] Titanium compounds are not considered to have the toxicity shown by heavy metals represented by lead, tin, antimony, cadmium, chromium and the like (for example, “Zachs” toxic substance data book,
(Translated by Yoshio Fujiwara, Maruzen Co., Ltd., p. 360), if a practically usable high molecular weight polyester can be produced using as little titanium compound as possible, it is expected that it can be suitably used, for example, as a food-related packaging material.

[0005] In order to make polyester high molecular weight,
It is also conceivable to combine the polyester with a diisocyanate to achieve a high molecular weight. For example, conventionally, the number average molecular weight of which the terminal group is a hydroxyl group is 2,000 to 2,500.
Polyester as a raw material component of polyurethane resin, reacted with diisocyanate, rubber, foam,
Paints and adhesives are widely used. But,
The polyester used for the existing polyurethane is a so-called prepolymer having a number average molecular weight of 2,000 to 2,500. To obtain practical physical properties with respect to 100 parts by weight of the low molecular weight polyester, the molecular weight of diisocyanate is required. However, the amount of diisocyanate used is 10
Up to 20 parts by weight. However, as mentioned above,
For example, when 10 parts by weight or more of a diisocyanate is added to a molten polyester (about 150 ° C. or more depending on the type), both low-molecular-weight and high-molecular-weight polyesters gel without fail, and a handleable resin cannot be obtained. In practice, the addition of more than 10 parts by weight of the diisocyanate is either in solution in a solvent or obtains the final cured resin at one time, as found in foam or RIM molding. In the case of rubber, the hydroxyl group in the polyester is converted into an isocyanate group (by adding diisocyanate), and the molecular weight is further increased with glycol. However, the amount of isocyanate is changed as described above. It is as large as 10 parts by weight or more. At this time, if a heavy metal-based catalyst is used in the synthesis of the polyester, it significantly promotes the reactivity of the isocyanate group, thereby deteriorating the storage stability and causing undesirable cross-linking (branching). Is synthesized without a catalyst. Therefore, the number average molecular weight is limited to about 2,500 at the highest. The present invention solves the conventional problems as described above, using a titanium-based catalyst and a diisocyanate,
It is an object of the present invention to provide a method for producing a polyester containing a urethane bond, which has sufficient strength for practical use, has a high melting point, and can use a very small amount of a catalyst.

[0006]

DISCLOSURE OF THE INVENTION The present inventors have conducted extensive studies on dicarboxylic acids, which are constituent materials of polyesters, and glycols. As a result, ethylene glycol and the above dicarboxylic acids (or acid anhydrides thereof) were used as glycol components. Product) as a raw material, and when performing a deglycolization reaction using these, a titanium oxyacetylacetonate or an alkoxytitanium compound is used as a catalyst, and the resulting saturated polyester is further reacted with diisocyanate to obtain a polyester. Number average molecular weight of 2
To increase the number average molecular weight of the polyester to a desired level based on the above, to eliminate the difficulty of increasing the number average molecular weight of the polyester to a desired level, and to obtain a polyester containing urethane bonds having practically sufficient strength and a high melting point. As a result, the present invention has been completed. That is, the present invention relates to (a) ethylene glycol and a compound represented by the general formula:

[0007]

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In the process of esterifying a dicarboxylic acid or an acid anhydride thereof represented by the formula (where n is an integer of 2 to 12) and then subjecting it to a deglycol reaction, 100 parts by weight of the produced saturated polyester is removed. As the catalyst for the glycol reaction, 0.0001 to 0.1 parts by weight of a titanium oxyacetylacetonate or an alkoxytitanium compound is used, and the number-average molecular weight of which the terminal group is substantially a hydroxyl group is 5,000.
Synthesize a saturated polyester having a melting point of 60 ° C. or higher,
(B) urethane, characterized in that the saturated polyester obtained is melted, and 100 parts by weight thereof is reacted with 0.1 to 5 parts by weight of diisocyanate so that the number average molecular weight is 10,000 or more. It is intended to provide a method for producing a polyester containing a bond.

Hereinafter, the present invention will be described in more detail.
Unless otherwise specified, the number average molecular weight is simply expressed as molecular weight.

The production of a saturated polyester using ethylene glycol and the above dicarboxylic acid can be carried out by a known technique. The conditions for the esterification reaction and the deglycolization reaction when producing this saturated polyester can be set to appropriate conditions conventionally used, and are not particularly limited.

Further, other glycols such as 1,4-cyclohexanedimethanol, 1,4-butanediol, neopentyl glycol and the like may be used as long as the physical properties (eg, high melting point) of the polyester obtained by the present invention are not impaired. They can be used together. The amount of the glycol component used in the present invention is equimolar to the dicarboxylic acid component, but generally there is distilling during esterification,
Used slightly excessively.

The dicarboxylic acid used in combination with ethylene glycol has the general formula

[0013]

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Wherein n is an integer of 2 to 12 or an acid anhydride thereof, such as succinic acid,
Adipic acid, suberic acid, sebacic acid, dodecanoic acid and the like can be mentioned, among which succinic acid, and further, a mixed acid of succinic acid and other dicarboxylic acids, for example, adipic acid, suberic acid, sebacic acid, dodecanoic acid. It is suitable.
When a mixed acid is used, for example, a suitable mixing ratio of each component of a two-component system or more composed of succinic acid and another dicarboxylic acid is usually 50 mol% or more of succinic acid, preferably 60 mol% or more, The content of dicarboxylic acids other than succinic acid is 50 mol% or less, preferably 40 mol% or less.

The catalyst used in the present invention has the general formula Ti
(OR) _{4 wherein} R represents an alkyl group having 1 to 4 carbon atoms, or an alkoxytitanium compound or titanium oxyacetylacetonate. Titanium oxyacetylacetonate has the general formula

[0016]

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## EQU1 ## The amount of the catalyst used is 0.0001 parts by weight based on 100 parts by weight of a saturated polyester obtained by reacting ethylene glycol and dicarboxylic acid.
The amount is preferably 0.1 to 0.1 part by weight, more preferably 0.001 to 0.01 part by weight. If the amount is less than 0.0001 part by weight, the action of the catalyst becomes weak, and it becomes difficult to obtain a target molecular weight. Further, even if the amount is more than 0.1 part by weight, the effect is not largely changed, and only the catalyst residue increases, which is not preferable. The deglycolization catalyst may be added from the beginning of the esterification reaction between glycol and dicarboxylic acid, or may be added after the esterification reaction is completed.

Next, the addition and reaction of the diisocyanate will be described. The diisocyanate used to further increase the molecular weight of the produced polyester having a molecular weight of 5,000 or more, desirably 10,000 or more, which is a component of the present invention, and having a substantially hydroxyl group, is not particularly limited. A commercially available product can be used as it is. Examples include 2,4-tolylene diisocyanate, a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, hydrogenated Xylylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate are preferable. Among them, hexamethylene diisocyanate is preferable from the viewpoint of the hue of the formed resin, the reactivity when added to the saturated polyester, and the like. The amount of the diisocyanate used depends on the molecular weight, but is preferably 0.1 to 5 parts by weight based on 100 parts of the saturated polyester in a molten state.
Preferably it is 0.5 to 3 parts by weight. The addition of the diisocyanate is preferably performed under a condition in which the saturated polyester is in a uniform molten state, does not contain a solvent, and can be easily stirred. Separately, it is not impossible to add diisocyanate to solid saturated polyester and melt and mix it through an extruder, but generally, in a saturated polyester production apparatus or in a molten polyester (for example, in a kneader). Is practical.

In the present invention, the saturated polyester to be reacted with the diisocyanate has a molecular weight of at least 5,000, preferably at least 10,000, whose terminal group is substantially a hydroxyl group.
Those having a melting point of at least 000 and a melting point of at least 60 ° C. are preferred. When the saturated polyester has a low molecular weight, for example, a molecular weight of about 2,500, even if 0.1 to 5 parts by weight of the diisocyanate used in the present invention is used, a final resin having good physical properties cannot be obtained. In addition, in the case of melt addition, if 0.1 to 5 parts by weight of diisocyanate is added, there is an inconvenience that gelation occurs during the reaction. Therefore, unless the terminal hydroxyl value is about 30 or less, a safe reaction cannot be performed. The molecular weight of the present invention is 5,000.
Saturated polyester of 0 or more necessarily has a hydroxyl value of this level or lower, and the use of a small amount of diisocyanate enables safe synthesis of a high molecular weight polyester even under severe conditions such as a molten state. Therefore, the polyester produced according to the present invention will contain at least one urethane bond per 5,000 molecular weight. The molecular weight of 10,000 or more produced as described above,
Preferably, a polyester containing at least 20,000 urethane bonds has practically sufficient strength and flexibility and a high melting point, so that various molding methods can be used according to various uses. For example, when forming a film using this, a known film forming method can be used,
There is no particular limitation. The film can be used as a packaging material. Further, at the time of molding, various molding auxiliaries, for example, fillers (inorganic and organic), coloring agents, reinforcing materials, waxes, thermoplastic polymers, oligomers, and the like can be used in combination depending on the use.

[0020]

The present invention will be described below by way of examples. Example 1 Ethylene glycol 2 was placed in a 1-liter separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas inlet tube.
After adding 04 g, 354 g of succinic acid, and 0.03 g of tetraisopropyl titanate, the mixture was esterified in a nitrogen stream at 195 to 205 ° C. to adjust the acid value to 8.9, and finally to 0.5.
The pressure was reduced to Torr, and the glycol was deglycoled at 210 to 215 ° C. for 10 hours.
(Shodex GPC SYSTEM-11, GPC using Showa Denko
As a result of the analysis, the same applies hereinafter). Upon cooling to room temperature, it became a white wax with a melting point of about 105 ° C. and an acid value of almost 0. The remaining amount of 10 g taken out of the obtained polyester (A) was heated to 205 to 206 ° C. and melted, and 6 g of hexamethylene diisocyanate was added with stirring. The viscosity increased rapidly,
No gelling occurred. The mixture was stirred for 20 minutes and cooled. The obtained polyester (B) containing a urethane bond had a molecular weight of 26,000, a slightly yellowish white wax, and a melting point of 107 to 108 ° C. The polyester (A) and the polyester (B) were each stretched 3 × 4 times in each direction by a biaxial stretching apparatus to produce a film having a thickness of about 30 μm at 80 ° C. Shortly after the start of stretching, the film was broken, and a film could not be formed. However, the polyester (B) formed a transparent film. The tensile strength of this transparent film (measured according to JIS K6760) is
It was 1,640 kg / cm ² .

Example 2 Ethylene glycol 1 was placed in a 1-liter separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas inlet tube.
40 g, 176 g of succinic acid, 58 g of adipic acid and 0.015 g of titanium oxyacetylacetonate were charged and esterified in a nitrogen stream at 195 to 205 ° C. to give an acid value of 7.1.
After that, the pressure was finally reduced to 0.5 Torr,
A deglycol reaction was performed at 220 ° C for 10 hours, and a molecular weight of 1
2,100 polyesters (C) were obtained. Upon cooling to room temperature, it turned into a pale tan wax, with a melting point of about 75 ° C. The remaining amount of 10 g taken out of the obtained polyester (C) was heated to a temperature of 205 to 206 ° C. and melted.
g was added. The viscosity increased rapidly but no gelling occurred. After stirring for 20 minutes, the polyester (D) containing a urethane bond obtained by cooling has a molecular weight of 31,400,
It was a pale yellowish white wax with a melting point of about 80 ° C. As in Example 1, the polyester (C) and the polyester (D) were each stretched 3 × 4 times at 80 ° C. using a biaxial stretching apparatus to produce a film having a thickness of about 30 μm. C) was broken immediately after the start of stretching, and a film could not be formed, but polyester (D) formed a transparent film. The tensile strength of this transparent film (measured according to JIS K6760) is
It was 1,820 kg / cm ² .

Example 3 Ethylene glycol 1 was placed in a 1-liter separable flask equipped with a stirrer, a distillation condenser, a thermometer, and a gas inlet tube.
15 g, 1,4-butanediol 40 g, dodecanoic acid 46
0 g and 0.02 g of tetrabutoxytitanate were esterified in a nitrogen stream at 200 to 205 ° C. to give an acid value of 5.
4 and finally reduce the pressure to 0.6 Torr,
Perform a deglycol reaction at ~ 220 ° C for 10 hours,
16,400 polyesters (E) were obtained. Upon cooling to room temperature, it became a slightly brownish wax and had a melting point of about 65 ° C. The whole amount of the obtained polyester (E) was heated to 200 to 202 ° C. and melted, and 5 g of xylylenemethane diisocyanate was added with stirring. The viscosity increased rapidly but no gelling occurred.
After stirring for 20 minutes, the obtained polyester (F) containing a urethane bond had a molecular weight of 39,400, a pale yellowish brown wax, and a melting point of about 68 to 70 ° C. As in Example 1, the tensile strength (JIS) of a 30 μm thick film obtained by biaxially stretching the polyester (F) 5 times in each direction.
(Measured by K6760) was 1,440 kg / cm ² .

[0023]

According to the present invention, there is provided a method for producing a polyester containing a urethane bond, which has sufficient strength for practical use, has a high melting point, and can use a very small amount of a catalyst.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08G 18/42 C08G 63/00-63/91

Claims (1)

(57) [Claims] (A) ethylene glycol and a compound represented by the general formula: (Where n is an integer of 2 to 12), in the process of esterifying a dicarboxylic acid or an acid anhydride thereof, followed by a deglycol reaction, with respect to 100 parts by weight of the produced saturated polyester, 0.0001 ~ as catalyst
Using 0.1 part by weight of a titanium oxyacetylacetonate or an alkoxytitanium compound, a saturated polyester having a number average molecular weight of 5,000 or more and a melting point of 60 ° C. or more, whose terminal group is substantially a hydroxyl group, is synthesized. The saturated polyester obtained in a molten state is reacted with 0.1 to 5 parts by weight of diisocyanate with respect to 100 parts by weight of the saturated polyester to have a number average molecular weight of 10,000 or more. Production method.