JP3050963B2 - 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 useful for forming films, fibers and other molded articles, which 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 formability is high, 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 have relatively high strength, and if they are esterified with an aliphatic dicarboxylic acid such as adipic acid, sebacic acid or dodecanoic acid, sufficient strength can be obtained. Nevertheless, it has been found that film-forming polyesters can be produced. 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, which is unique compared to the fact that most of the aliphatic polyesters have a melting point of 70 ° C or less. It is a target. However, 1,4
-Aliphatic polyesters produced using butanediol and succinic acid are crystalline and undergo normal esterification and deglycolization reactions to a number average molecular weight of 10,000 to 1
Even at 5,000, there is a slight tendency to be fragile. 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 practical 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 done either in solution in a solvent or to obtain 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 for the synthesis of polyester,
Since this significantly promotes the reactivity of the isocyanate group, deteriorating the storage stability and causing undesired cross-linking (branching), low-molecular-weight polyester as a polyurethane raw material resin is generally 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,
It is an object of the present invention to provide a method for producing a polyester containing a urethane bond, which has a practically sufficient strength and a high melting point using a titanium-based catalyst and a diisocyanate, and can use an extremely small amount of a catalyst. Is what you do.

[0006]

The present inventors have conducted extensive studies on dicarboxylic acid, which is a constituent material of polyester, and glycols.
When cyclohexanedimethanol and the above-mentioned dicarboxylic acid (or an acid anhydride thereof) are used as raw materials and a deglycolization reaction is carried out using these, a titanium oxyacetylacetonate or an alkoxytitanium compound is used as a catalyst, and the obtained saturated By further reacting the polyester with a diisocyanate, the number average molecular weight of the polyester is increased by 2 to 5 times, and the difficulty of increasing the number average molecular weight of the polyester to a desired level based on it is solved. The inventors have found that a polyester having a urethane bond having high strength and a high melting point can be obtained, and the present invention has been completed. That is, the present invention relates to (a) 1,4-cyclohexanedimethanol and a compound represented by the general formula:

[0007]

Embedded image

In the process of esterifying a dicarboxylic acid or an acid anhydride thereof represented by the formula (wherein n represents 2 to 12) and then subjecting it to a deglycol reaction, 100 parts by weight of the produced saturated polyester is subjected to deglycidation. 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 the terminal group is substantially a hydroxyl group of 5,000.
The above saturated polyester is synthesized, (b) the obtained saturated polyester is melted, and 100 parts by weight thereof is reacted with 0.1 to 5 parts by weight of diisocyanate to make the number average molecular weight 10,000 or more. And a method for producing a polyester containing a urethane 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 1,4-cyclohexanedimethanol and the above dicarboxylic acid can be performed 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.

The 1,4-cyclohexanedimethanol used in the present invention has the general formula

[0012]

Embedded image

These are classified into cis-form and trans-form. In order to produce an aliphatic polyester having a high melting point, the trans-form is preferred. For example, from Eastman Industrial Chemicals of the United States,
A mixture of 1,4-cyclohexanedimethanol in a cis-to-trans ratio of 1: 2 is commercially available, but can also be used in the present invention.

Further, other glycols such as ethylene glycol, 1,4-butanediol, neopentyl glycol and the like can be used in combination as long as the physical properties (eg, high melting point) of the polyester obtained by the present invention are not impaired. . The amount of the glycol component used in the present invention is equimolar to the dicarboxylic acid component, but is generally used in a slightly excessive amount due to distillation during esterification.

The dicarboxylic acid used in combination with 1,4-cyclohexanedimethanol has the general formula

[0016]

Embedded image

(Where 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.
Question Please consider.

The catalyst used in the present invention has a 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

[0019]

Embedded image

[0020] The catalyst is used in an amount of 0.0001 to 0.1 part by weight, preferably 0.001 to 0.01 part by weight, based on 100 parts by weight of a saturated polyester obtained by reacting 1,4-cyclohexanedimethanol with dicarboxylic acid. Parts by weight are good. 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 added to further increase the molecular weight of the resulting polyester having a molecular weight of 5,000 or more, desirably 10,000 or more, which is a substantially hydroxyl group, which is a constituent element of the present invention, is not particularly limited, and it is commercially available. 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 depends on the molecular weight, but is 0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight, based on 100 parts of the saturated polyester in the molten state. 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, add diisocyanate to solid saturated polyester, melt through extruder,
It is not impossible to mix, but it is generally practical to add it to the saturated polyester production equipment or to the molten polyester (eg, in a kneader).

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.
000 or more is good. Saturated polyester has low molecular weight,
For example, when the molecular weight is about 2,500, even when using 0.1 to 5 parts by weight of diisocyanate used in the present invention,
Not only is it not possible to obtain a final resin having good physical properties, but also in the case of melt addition, when 0.1 to 5 parts by weight of diisocyanate is added, gelation is observed during the reaction. There is. Therefore, unless the terminal hydroxyl value is about 30 or less, a safe reaction cannot be performed. The saturated polyester having a molecular weight of 5,000 or more of the present invention necessarily has a hydroxyl value of this level or less, and can safely synthesize a high-molecular-weight polyester even under severe conditions such as a molten state by using a small amount of diisocyanate. be able to. Therefore, the polyester produced according to the present invention has a molecular weight of at least 5,000.
It will contain one urethane bond per zero. The polyester containing a urethane bond having a molecular weight of 10,000 or more, preferably 20,000 or more, produced as described above has sufficient strength and flexibility for practical use, and has a melting point of 70 or more.
Since the temperature is as high as ° C. or more, various molding methods can be used according to various uses. For example, when a film is formed using this, a known film forming method can be used, and 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.

[0023]

The present invention will be described below by way of examples. Example 1 A 1-liter separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas inlet tube was charged with 300 g of 1,4-cyclohexanedimethanol and 236 g of succinic acid, and esterified at 205 to 210 ° C. in a nitrogen stream. To 7.9
After that, 0.04 g of tetraisopropyl titanate was added, and finally the pressure was reduced to 0.6 Torr, and the pressure was reduced to 210 to 215.
A deglycol reaction was performed at 10 ° C. for 10 hours to obtain a polyester (A) having a molecular weight of 16,600. When cooled to room temperature,
It became a white wax, the melting point was about 115 ° C., and the acid value was almost 0. The analysis was performed by Shodex GPC SYSTEM-1.
1. GPC analysis using Showa Denko KK (the same applies hereinafter). The remaining amount of 10 g taken out from the obtained polyester (A) was heated to 200 to 201 ° C. and melted.
While stirring this, hexamethylene diisocyanate 7
g was added. The viscosity increased rapidly but no gelling occurred. The mixture was stirred for 20 minutes and cooled. Polyester (B) containing urethane bond obtained
Has a molecular weight of 38,100, is a white wax, and has a melting point of 11
5-117 ° C. The polyester (A) and the polyester (B) were each heated at 90 ° C. by a biaxial stretching device.
When it was attempted to produce a film having a thickness of about 30 μm under the stretching conditions of 3 × 4 times, the polyester (A) was broken and a film could not be formed, but the polyester (B) formed a transparent film. Was. The tensile strength of this transparent film (measured according to JIS K6760) is 1
It was 740 kg / cm ² .

EXAMPLE 2 300 g of 1,4-cyclohexanedimethanol, 292 g of adipic acid, 0.028 g of titanium oxyacetylacetonate were placed in a 1-liter separable flask equipped with a stirrer, a fractionating condenser, a thermometer and a gas inlet tube. And acidified at 205 to 210 ° C. in a nitrogen stream to make the acid value 5.1, and finally, the pressure was reduced to 0.6 Torr and the pressure was reduced to 210 to 21.
Perform a deglycol reaction at 5 ° C for 10 hours to obtain a molecular weight of 16,900.
The polyester (C) was obtained. Upon cooling to room temperature, it became a slightly yellowish white wax with a melting point of about 105 ° C. The remaining amount of 10 g taken out of the obtained polyester (C) was heated to 200 to 201 ° C. and melted, and 8 g of isophorone diisocyanate was added with stirring. The viscosity increased rapidly but no gelling occurred. The obtained polyester (D) containing a urethane bond had a molecular weight of 36,900, a light yellowish brown wax, and a melting point of about 108 ° C. Polyester (C)
And polyester (D) 4 × 3 times at 80 ° C.
The film is stretched in each direction by a biaxial stretching device, and the thickness is about 30μ.
When an attempt was made to produce a film of m, the polyester (C) was broken in the middle and a film could not be formed, but a transparent film was formed of the polyester (D). The tensile strength of this transparent film (JIS K6760)
Was 1590 kg / cm ² .

Example 3 A 1-liter separable flask equipped with a stirrer, a fractionating condenser, a thermometer and a gas inlet tube was charged with 288 g of 1,4-cyclohexanedimethanol, 55 g of 1,4-butanediol, 236 g of succinic acid, 115 g of dodecanoic acid and 0.04 g of titanium oxyacetylacetonate were charged and 205
After esterification at ~ 210 ° C to an acid value of 9.4, the pressure was finally reduced to 0.6 Torr, and
Deglycol-reaction was performed for 2 hours to obtain a polyester (E) having a molecular weight of 16,900. Upon cooling to room temperature, it became a pale yellow wax and had a melting point of 72 ° C. The obtained polyester (E) was heated to 201 to 202 ° C. and melted, and 7 g of diphenylmethane diisocyanate was added with stirring. The viscosity increased rapidly but no gelling occurred. The obtained polyester (F) containing a urethane bond had a molecular weight of 31,800, a yellowish brown wax, and a melting point of about 75 ° C.

[0026]

According to the present invention, there is provided a process for producing a polyester containing urethane bonds, which has sufficient strength for practical use, has a high melting point, uses a very small amount of catalyst, and has a film-forming ability. .

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08G 18/42 C08G 63/78-63/91

Claims (1)

(57) [Claims] (1) (a) 1,4-cyclohexanedimethanol and a compound represented by the general formula: (Wherein, n represents 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 whose terminal group is substantially a hydroxyl group is synthesized. (B) The obtained saturated polyester is A method for producing a polyester containing a urethane bond, wherein the polyester is brought into a molten state, and 100 parts by weight thereof is reacted with 0.1 to 5 parts by weight of diisocyanate to have a number average molecular weight of 10,000 or more.