JPH0570578A - Production of polyester having urethane bonds - Google Patents

Abstract

PURPOSE:To increase strengths and m.p. by esterifying 1,4- cyclohexanedimethanol with a dicarboxylic acid (anhydride), eliminating the glycol molecules from the resulting ester in the presence of a specific catalyst, and reacting the resulting polyester with a diisocyanate. CONSTITUTION:A hydroxyl-terminated, satd. polyester having a number-average mol.wt. of least 5,000 is produced by esterifying 1,4-cyclohexanedimethanol of formula I with a dicarboxylic acid for formula II (wherein n is 2-12) or its anhydride, adding 0.0001-0.1 pt.wt (based on 100 pts.wt the satd polyester) catalyst consisting of an alkoxytitanium compd. of the formula: Ti (OR) 4 (wherein R is 1-4C alkyl) or titanium oxyacetylacetonate of formula III to the reaction system, and eliminating the glycol molecules from the resulting ester. 100 pts.wt. thus obtd. polyester in a molten state is reacted with 0.1-5 pts.wt. diisocyanate to give the title polyester having a number-average mol.wt. of 10,000 or higher.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyester having a urethane bond, which has a practically sufficient strength, a high melting point, and a very small amount of a catalyst, and which is useful for forming films, fibers and other molded articles. The present invention relates to a manufacturing method.

[0002]

BACKGROUND OF THE INVENTION Aliphatic saturated polyesters are
Generally, the melting point is low, most of them are 70 ° C. or less, and even if the number average molecular weight is in the high molecular weight region of 10,000 or more, a polyester having a saturated aromatic structure, such as polyethylene terephthalate, has practically sufficient mechanical properties. Until now, it has been considered impractical because it has no physical properties. In fact, even if the film-forming property was good, the produced film was weak in tear strength and tensile strength and could not be used practically. Among these, aliphatic polyesters containing 1,4-butanediol as a glycol component have relatively high strength, and if they are esterified with aliphatic dicarboxylic acids such as adipic acid, sebacic acid, and dodecanoic acid, sufficient strength can be obtained. However, it has been found that a film-formable polyester can be produced. Particularly, in the case of an aliphatic polyester produced by using succinic acid as a dicarboxylic acid, the melting point is as high as 110 to 115 ° C., and most of the aliphatic polyesters show a melting point of 70 ° C. or less, which is specific. Target. However, 1,4
-The aliphatic polyester produced using butanediol and succinic acid is crystalline and undergoes the usual esterification and deglycolization reaction to give a number average molecular weight of 10,000 to 1
Even at 5,000, a slightly fragile tendency is recognized. This brittleness can be improved by using other dicarboxylic acids such as adipic acid, sebacic acid and dodecanoic acid in combination, but there is still a problem in providing practical film strength. As the number of methylene bonds between the carboxyl groups increases, the flexibility tends to increase, 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 a reaction. If these catalysts are used in sufficient amounts, 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 the obtained polyester is used as a packaging material for foods. In this case, it is desired that the amount of these catalysts used is as small as possible.

Titanium compounds are not considered to be toxic by heavy metals represented by lead, tin, antimony, cadmium, chromium, etc. (for example, "Zachs" hazardous substance data book,
If a high-molecular-weight polyester having a practical use can be produced by using a titanium compound in an extremely small amount, it is expected that it can be suitably used as a packaging material for food, for example.

In order to make polyester have a high molecular weight,
It is also conceivable to combine the polyester with a diisocyanate to a high molecular weight. For example, conventionally, a number average molecular weight of 2,000 to 2,500 in which a terminal group is a hydroxyl group
Polyester is used as a raw material component of polyurethane resin and reacted with diisocyanate to produce rubber, foam,
It is widely used as a paint or an adhesive. 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 100% by weight of this low molecular weight polyester, in order to obtain practical physical properties, the molecular weight of diisocyanate is Depending on the amount, the amount of diisocyanate used is 10
~ 20 parts by weight. However, as mentioned above,
For example, when 10 parts by weight or more of diisocyanate is added to molten polyester (depending on the kind, it is about 150 ° C. or higher), both low molecular weight and high molecular weight polyesters are necessarily gelated, and a handleable resin cannot be obtained. In practice, the addition of 10 parts by weight or more of the diisocyanate is carried out in solution in a solvent, or to obtain the final cured resin in one go, as found in foam or RIM molding. Further, in the case of rubber, it has also been carried out to convert the hydroxyl group in the polyester into an isocyanate group (adding diisocyanate) and further increase the molecular weight with glycol, but the amount of isocyanate is as described above. A large amount of 10 parts by weight or more. At this time, if a heavy metal-based catalyst is used for the synthesis of polyester,
Since this greatly accelerates the reactivity of the isocyanate group, deteriorates the storage stability, and causes undesired crosslinking (branching), low molecular weight polyesters as polyurethane raw material resins are generally synthesized without catalyst. Therefore, the maximum number average molecular weight is about 2,500 at the maximum. The present invention solves the conventional problems as described above,
An object of the present invention is to provide a method for producing a polyester containing a urethane bond, which has a titanium-based catalyst and a diisocyanate, has practically sufficient strength, has a high melting point, and can use a very small amount of the catalyst. To do.

[0006]

Means for Solving the Problems As a result of extensive studies of dicarboxylic acid, which is a constituent raw material of polyester, and glycols, the present inventors have found that 1,4-
Cyclohexanedimethanol and the above-mentioned dicarboxylic acid (or its acid anhydride) are used as raw materials, and when a deglycolization reaction is performed using them, a titanium oxyacetylacetonate or alkoxytitanium compound is used as a catalyst to obtain a saturated saturation. By further reacting the polyester with diisocyanate, the number average molecular weight of the polyester is increased to 2 to 5 times, and based on this, the difficulty of increasing the number average molecular weight of the polyester to a desired level is solved, and it is practically sufficient. It was found that a polyester having a urethane bond having strength and a high melting point can be obtained, and the present invention was completed. That is, the present invention relates to (a) 1,4-cyclohexanedimethanol and the general formula

[0007]

[Chemical 2]

In the process of esterifying a dicarboxylic acid represented by the formula (n represents 2 to 12) or an acid anhydride thereof and then performing a deglycol reaction, 100 parts by weight of the produced saturated polyester is deprotected. 0.0001 to 0.1 part by weight of titanium oxyacetylacetonate or alkoxytitanium compound is used as a catalyst for glycol reaction, and the number average molecular weight of the end group is substantially hydroxyl group is 5,000.
The above saturated polyester is synthesized, and (b) the obtained saturated polyester is made into a molten state, and 0.1 to 5 parts by weight of diisocyanate is reacted with 100 parts by weight thereof to make the number average molecular weight 10,000 or more. The present invention provides a method for producing a polyester containing a urethane bond.

The present invention will be described in more detail below.
Unless otherwise specified, the number average molecular weight is simply referred to as the molecular weight.

The production of a saturated polyester using 1,4-cyclohexanedimethanol and the above dicarboxylic acid can be carried out by a known technique. The esterification reaction and deglycolization reaction conditions for 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]

[Chemical 3]

## STR1 ## This is classified into a cis type and a trans type, and the trans type is preferable for producing an aliphatic polyester having a high melting point. Also, for example, from Eastman Industrial Chemicals, Inc.,
A mixture of cis and trans forms of 1,4-cyclohexanedimethanol in a ratio of 1: 2 is commercially available, but it can also be used in the present invention.

Further, other glycols such as ethylene glycol, 1,4-butanediol, neopentyl glycol and the like may be used in combination as long as the physical properties (for example, 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 it is generally used in a slight excess because distilling during esterification occurs.

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

[0016]

[Chemical 4]

(Wherein n is an integer of 2 to 12) or an acid anhydride thereof is preferable. For example, succinic acid,
Adipic acid, suberic acid, sebacic acid, dodecanoic acid and the like can be mentioned. Among them, succinic acid and further, succinic acid and other dicarboxylic acids, for example, mixed acid of adipic acid, suberic acid, sebacic acid, dodecanoic acid It is suitable.
When the mixed acid is used, for example, a suitable mixing ratio of each component of a two-component system or more consisting of succinic acid and another dicarboxylic acid is usually 50 mol% or more, preferably 60 mol% or more, for succinic acid. The dicarboxylic acid other than succinic acid is 50 mol% or less, preferably 40 mol% or less.
Please consider the question.

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

[0019]

[Chemical 5]

Can be represented by The amount of this catalyst used is 0.0001 to 0.1 part by weight, preferably 0.001 part by weight to 0.01 part by weight, relative to 100 parts by weight of a saturated polyester obtained by reacting 1,4-cyclohexanedimethanol and dicarboxylic acid. Good parts by weight. If the amount used is less than 0.0001 parts by weight, the action of the catalyst becomes weak and it becomes difficult to obtain the target molecular weight. Further, even if the amount used exceeds 0.1 part by weight, the action does not largely change, and only the catalyst residue increases, which is not preferable. The deglycolization catalyst may be added from the beginning of the esterification reaction of glycol and dicarboxylic acid, or may be added after the completion of the esterification reaction.

Next, the addition and reaction of diisocyanate will be described. The diisocyanate added to further increase the molecular weight is added to the polyester having a molecular weight of 5,000 or more, preferably 10,000 or more, whose end groups are substantially hydroxyl groups, which is a component of the present invention, and is not particularly limited. The one can be used as it is. Examples thereof 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, hydrogenation. Examples thereof include xylylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate. Among them, hexamethylene diisocyanate is preferable from the viewpoint of the hue of the produced resin, reactivity when added to saturated polyester, and the like. The addition amount of 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 diisocyanate is preferably added under a condition that the saturated polyester is in a uniformly molten state, does not contain a solvent, and can be easily stirred. Separately from this, diisocyanate is added to solid saturated polyester and melted through an extruder,
It is not impossible to mix them, but it is generally practical to add them to a saturated polyester production apparatus or to a molten polyester (for example, in a kneader).

In the present invention, the saturated polyester to be reacted with the diisocyanate has a terminal group which is substantially a hydroxyl group and has a molecular weight of 5,000 or more, preferably 10,
More than 000 is good. Saturated polyester has a low molecular weight,
For example, when the molecular weight is about 2,500, even if 0.1 to 5 parts by weight of diisocyanate used in the present invention is used,
In addition to the fact that the final resin having good physical properties cannot be obtained, in the case of addition of melt, addition of 0.1 to 5 parts by weight of diisocyanate may cause gelation during the reaction. There is. Therefore, a safe reaction cannot be performed unless the terminal hydroxyl value is about 30 or less. 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 lower, and a small amount of diisocyanate is used to safely synthesize a high molecular weight polyester even under severe conditions such as a molten state. 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 0. 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 practically sufficient strength and flexibility and has a melting point of 70.
Since it is as high as ℃ or higher, various molding methods can be used according to various applications. 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 aids such as fillers (inorganic or organic), colorants, reinforcing materials, waxes, thermoplastic polymers, oligomers and the like can be used in combination depending on the application.

[0023]

EXAMPLES The present invention will be described below with reference to examples. Example 1 A 1-liter separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas introduction tube was charged with 300 g of 1,4-cyclohexanedimethanol and 236 g of succinic acid, and the ester was heated at 205 to 210 ° C. in a nitrogen stream. Acid value to 7.9
After that, 0.04 g of tetraisopropyl titanate was added, and finally the pressure was reduced to 0.6 Torr, and 210 to 215
The glycol removal 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 and had a melting point of about 115 ° C. and an acid value of almost zero. In addition, the analysis is Shodex GPC SYSTEM-1
1. By GPC analysis using Showa Denko (the same applies below). The total amount of the remaining 10 g of the obtained polyester (A) was heated to 200 to 201 ° C. and melted,
Hexamethylene diisocyanate 7 while stirring this
g was added. The viscosity increased rapidly but no gelation occurred. The mixture was stirred for 20 minutes so as to be uniform and then cooled. Polyester (B) containing the obtained urethane bond
Has a molecular weight of 38,100, is a white wax, and has a melting point of 11
It was 5-117 degreeC. The polyester (A) and the polyester (B) are each biaxially stretched at 90 ° C.
When a film having a thickness of about 30 μm was tried to be produced under the stretching condition of 3 × 4 times, the polyester (A) was broken and the film could not be formed, but the polyester (B) formed a transparent film. It was The tensile strength of this transparent film (measured by JIS K6760) is 1
It was 740 kg / cm ² .

Example 2 300 g of 1,4-cyclohexanedimethanol, 292 g of adipic acid, and 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 introduction tube. Was charged, and the acid value was adjusted to 5.1 by esterification in a nitrogen stream at 205 to 210 ° C., and finally the pressure was reduced to 0.6 Torr and 210 to 21.
Deglycolization reaction at 5 ℃ for 10 hours, molecular weight 16,900
Polyester (C) was obtained. When cooled to room temperature, it became a slightly yellowish white wax and had a melting point of about 105 ° C. The total amount of the remaining 10 g of the obtained polyester (C) was heated to 200 to 201 ° C. to melt it, and 8 g of isophorone diisocyanate was added thereto while stirring. The viscosity increased rapidly but no gelation occurred. The obtained polyester (D) containing a urethane bond had a molecular weight of 36,900, a light tan wax-like form, and a melting point of about 108 ° C. Polyester (C)
And polyester (D) each 4 × 3 times 80 ℃
The film is stretched in each direction with 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 for the polyester (D). 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, and 236 g of succinic acid. Dodecanoic acid (115 g) and titanium oxyacetylacetonate (0.04 g) were charged, and the mixture was put in a nitrogen stream to give 205
After esterification at ~ 210 ° C to acid value of 9.4, the pressure is finally reduced to 0.6 Torr, and 210 ~ 215 ° C for 1 hour.
The glycol removal reaction was carried out for 2 hours to obtain a polyester (E) having a molecular weight of 16,900. When cooled 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. to melt it, and 7 g of diphenylmethane diisocyanate was added while stirring this. The viscosity increased rapidly but no gelation 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]

EFFECTS OF THE INVENTION The present invention provides a method for producing a polyester having a urethane bond having a film-forming ability, which has a practically sufficient strength, a high melting point, and a very small amount of catalyst. ..

Claims (1)

[Claims] 1. (a) 1,4-Cyclohexanedimethanol and a compound represented by the general formula: (In the formula, n represents 2 to 12) In the process of esterifying a dicarboxylic acid or an acid anhydride thereof and then performing a deglycol reaction, 100 parts by weight of the produced saturated polyester is subjected to the deglycol reaction. 0.0001 ~ as a 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, and (b) the obtained saturated polyester is synthesized. A process for producing a polyester containing a urethane bond, which comprises bringing the melted state into 100 parts by weight and reacting 0.1 to 5 parts by weight of diisocyanate to make the number average molecular weight 10,000 or more.