JP2860182B2 - Method for producing polyester containing urethane bond - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a process for producing a saturated aliphatic polyester having a practically sufficient high molecular weight and containing a small amount of urethane bonds (including alicyclic glycol, hereinafter simply referred to as polyester). In particular, the present invention relates to the production of a polyester which requires a light color and is free from harmful heavy metals.

[0002]

2. Description of the Related Art When synthesizing polyethylene terephthalate having a practically sufficient molecular weight, titanium, zinc, manganese, iron,
It is well known to use organic alkoxy compounds of heavy metals such as lead and antimony, and metal salts of organic acids as catalysts. 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 there is no problem if such a catalyst is used. It is desired that the amount be as small as possible. However, it has been reported that germanium compounds have low activity (for example, see “Synthetic Polymers, Vol. 5,” p. 214, published by Asakura Shoten). On the other hand, germanium compounds are not considered to have the toxicity shown by various heavy metals typified by lead, tin, antimony and the like, and for example, dioxide is known to have a pharmacological action to promote the formation of red blood cells ("Zachs"). Hazardous Substances Data Book, translated by Norio Fujiwara,
Maruzen Co., Ltd., p.197). Therefore, if a practical high-molecular-weight polyester can be synthesized using a germanium compound, it is expected to be very desirable for food-related packaging materials.

For example, conventionally, a polyester having a hydroxyl group at the terminal group and having a molecular weight of about 2,000 to 2,500 has been used as a raw material component of a polyurethane resin and reacted with diisocyanate to form a rubber, foam, paint, adhesive or the like. Is widely practiced. However, the polyester used for the existing polyurethane has a molecular weight of 2,000 to 2,500.
0, a so-called prepolymer. With respect to 100 parts by weight (hereinafter, weight is omitted) of this low molecular weight polyester, in order to obtain practical physical properties, although it depends on the molecular weight of the diisocyanate, 10 to 15 copies
It needs to reach ~ 20 parts. However, for example, 1
When 0 parts or more of diisocyanate is added to the molten polyester (almost 150 ° C. or more, depending on the type), if it is a low molecular weight polyester, it always gels and can be handled regardless of the high molecular weight polyester. No resin is obtained. In practice, the addition of 10 parts or more of the diisocyanate is carried out in solution in a solvent or to obtain the final cured resin at one time, as in foam or RIM molding. . In the case of rubber, the hydroxyl group is converted to an isocyanate group (by adding diisocyanate), and the molecular weight is further increased with glycol. However, the amount of isocyanate is 10 parts or more as described above. That's a lot. In such a case, when a heavy metal-based catalyst is used in the synthesis of the polyester, it greatly promotes the reactivity of the isocyanate group, resulting in poor storage stability and undesired crosslinking (branching). The raw material low molecular weight polyester is synthesized without a catalyst. Therefore, the molecular weight is at most 2,500
Place is the limit.

[0004]

Means for Solving the Problems The present inventors have synthesized a polyester having a number average molecular weight of 5,000 or more, preferably 10,000 or more, using a germanium compound as a catalyst for a deglycolization reaction. By adding 0.01 to 5 parts by weight of diisocyanate in the molten state of the above, the molecular weight of the polyester becomes 2 to 2.
The present invention has been completed by finding that the activity is increased by a factor of five, thereby eliminating the poor activity of the germanium catalyst and the difficulty of increasing the molecular weight of the polyester based thereon to a desired level. That is, the present invention
(A) In the course of synthesizing a saturated aliphatic polyester resin, 0.01 to 3 parts by weight of a germanium compound is used as a deglycolization catalyst with respect to 100 parts by weight of a produced resin, and the terminal group is substantially a hydroxyl group. Number average molecular weight 5,
(B) synthesizing 000 or more saturated aliphatic polyesters;
An object of the present invention is to provide a method for producing a polyester containing a urethane bond having a number average molecular weight of 10,000 or more, comprising adding 0.1 to 5 parts by weight of diisocyanate to the saturated aliphatic polyester in a molten state. Hereinafter, the present invention will be described in more detail.

(Saturated polyester) In the present invention,
The saturated polyester to be reacted with the diisocyanate must be a saturated polyester having a number average molecular weight of 5,000 or more, preferably 10.000 or more, wherein the terminal groups are substantially hydroxyl groups. If this is a low molecular weight polyester, for example, the number average molecular weight is about 2500,
Even with the use of 0.1 to 5 parts by weight of the 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, the aforementioned 0.1 resin is used.
Even in the case of 1 to 5 parts by weight, there is an inconvenience that gelation occurs during the reaction depending on the amount. Therefore, unless the number of terminal hydroxyl groups per unit weight (ie, the size of the molecule) is about 30 or less, a safe reaction cannot be performed. The 5,000 or higher molecular weight polyesters of the present invention necessarily have a hydroxyl number at this level or below,
By using a small amount of diisocyanate, a high molecular weight polyester can be synthesized safely even under severe conditions such as a molten state. Therefore, the polyester referred to in the present invention contains at least one urethane bond per 5,000 molecular weight. Polyester having a molecular weight of 10,000 or more, preferably 20,000 or more, obtained by the present invention can be made into a tough film as long as it has a melting point of 60 ° C. or more and is crystalline, and can be used as a packaging material. It is. Glycols used for this purpose include, for example, ethylene glycol, butanediol 1,4, hexanediol 1,6, decamethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol and the like. Ethylene oxide can also be used. Polybasic acids (or their anhydrides) that react with these glycols to form polyesters include succinic acid, adipic acid, suberic acid, sebacic acid,
Dodecanoic acid, succinic anhydride, adipic anhydride, and the like are generally commercially available and can be used in the present invention.
In particular, butanediol 1,4 and succinic acid (melting point 110-
115 ° C.), and a combination of ethylene glycol and succinic acid (melting point about 105 ° C.) shows a melting point similar to that of polyethylene, and is the most desirable combination for the present invention. Naturally, as long as the purpose is not impaired,
Glycol and polybasic acid can be used together. In the saturated polyester of the present invention, the terminal group is substantially a hydroxyl group. For this purpose, the proportion of the glycol component and the acid component used in the synthesis reaction requires a slight excess of glycol. The method for synthesizing the polyester is not particularly limited, and is generally increased in molecular weight by a deglycolization reaction following esterification.

(Catalyst) The germanium compound used as a catalyst in the synthesis of the saturated aliphatic polyester of the present invention is as follows:
There are inorganic and organic compounds, but in fact availability,
Commercially available types are limited due to cost, stability, and the like. Examples thereof include germanium oxide and germanium phosphate as inorganic compounds, and tetrabutylgermanium, tetraphenylgermanium, tetraethoxygermanium and tetrabutoxygermanium as organic compounds. Handling, price,
Taking into account the activity as a catalyst, tetraethoxygermanium, tetrabutoxygermanium, germanium oxide and the like are suitable. The usage ratio of the germanium compound is 0.01 to 3 parts by weight, preferably 0.5 to 2 parts by weight, based on 100 parts by weight of the saturated aliphatic polyester to be produced. The germanium compound may be added from the beginning of the esterification or may be added immediately before the deglycolization reaction.

(Diisocyanate component) Further, the molecular weight of the resulting polyester, which is a constituent element of the present invention and has a molecular weight of 5,000 or more, preferably 10,000 or more, is substantially a hydroxyl group, is further increased. The diisocyanates added for this purpose are not particularly limited, and examples thereof include the following commercially available types. 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, isophorone diisocyanate, particularly hexamethylene diisocyanate, the color of the formed resin It is preferable from the viewpoint of the reactivity at the time of adding the polyester. The amount of these diisocyanates depends on the molecular weight,
The amount is 0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight based on 100 parts of the polyester. The addition is desirably performed under conditions in which the polyester is in a homogeneous molten state, does not contain a solvent, and can be easily stirred. Separately, it is not impossible to add to a solid polyester and melt and mix through an extruder, but generally, it is added to a polyester manufacturing apparatus or to a molten polyester (for example, in a kneader). Is practical. The polyester containing a small amount of urethane bonds according to the present invention can be formed into films, sheets, etc., and is mainly used for coloring. However, when used, lubricants, coloring agents, other polymers, release agents, fillers, reinforcing materials, etc. Can be used if necessary.

[0008]

EXAMPLES Next, examples will be shown below to facilitate understanding of the present invention. Example 1 315 g of butanediol 1,4 and 348 g of succinic acid were charged into a 1 liter separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas inlet tube, and then heated to 190 to 200.
After esterification in a nitrogen gas stream to give an acid value of 8.1 (number average molecular weight of about 2,600), 2 g of tetra-n-butoxygermanium manufactured by Nippon Kagaku Sangyo Co., Ltd. was added, and the mixture was heated at 200 to 205 ° C. About 18 hours and finally 0.1
The pressure was reduced to 6 Torr to increase the molecular weight by a glycol removal reaction. The obtained polyester (A) had a number-average molecular weight of 16,200 at room temperature and was a white hard wax, and the melting point was 110 to 115 ° C. For the measurement of molecular weight, refer to “Shocle
x GPC SYSTEM-11 ”and eluent 5mM CF ₃ COONa4HFTP
I went in. Further, 6 g of hexamethylene diisocyanate was added to the polyester (A) in a molten state at 206 ° C., and the mixture was stirred and reacted. No gelling occurred. The number average molecular weight of the resulting polyester (B) containing a small amount of urethane bonds was 33,000. 5 g of polyester (A) and (B) on a hot plate coated with a release agent at 130 ° C.
Was press-molded at 10 kg / cm ² to form an opaque disk and cut into 3 cm × 3 cm at room temperature. When this was stretched at a temperature of 80 ° C. in a biaxial stretching machine of 5 × length and width, the polyester (A) was torn in the middle and a stretched film could not be obtained. Gave a transparent stretched tough film having a thickness of about 30 μm, and its tensile strength was 500 kg / cm ² .

Example 2 Ethylene glycol 21 was placed in a 1 l separable flask equipped with a stirrer, a distillation condenser, a thermometer and a gas inlet tube.
5 g, 354 g of succinic acid and 1.2 g of germanium oxide were charged and esterified at 195 to 200 ° C. to an acid value of 9.2, and then at a temperature of 205 to 210 ° C. for a total of 16 hours, and finally a reduced pressure of 0.4 Torr. Deglycolization was performed below. At room temperature, a white solid polyester (C) has a number average molecular weight of 15,
000. 201 ° C for polyester (C)
Then, 5.7 g of diphenylmethane diisocyanate is added,
Urethane conversion was performed. After the reaction for 10 minutes, the number average molecular weight was 39,000, and upon cooling to room temperature, a light yellow wax-like polyester (D) containing a small amount of urethane bonds was obtained. 5 g each of polyester (C) and polyester (D)
Is sandwiched between polyethylene terephthalate films having a thickness of 100 μm and a thickness of about 1 at 130 ° C. under a pressure of 10 kg / cm ^2.
It was formed into a 50μ opaque disk. Polyester (C)
In this state, polyester (D) containing a small amount of urethane bonds is very tough, and can not be torn by hand, while it can be easily torn by hand and gives a fragile feeling. A transparent film having a thickness of about 30 μm was obtained by stretching 5 times each in the vertical and horizontal directions at ℃, and its tensile strength was 560 kg / cm ² .

Example 3 Into a 1 l separable flask equipped with a stirrer, a distillation condenser and a thermometer, 272 g of hexanediol 1.6 and 460 g of dodecanoic acid were charged and esterified at 200 to 205 ° C. in a nitrogen stream. After adjusting the acid value to 7.3, 1.5 g of tetra-n-ethoxygermanium manufactured by Nippon Chemical Industry Co., Ltd.
In addition, the pressure was finally reduced to 0.4 Torr at 210 to 215 ° C., and the mixture was deglycolized for 18 hours to obtain a number average molecular weight of 1
At room temperature, 6,100 polyesters (E) were obtained as white waxy polymers. Melting point was about 80-85 ° C. When the temperature was lowered to 200 ° C. and 10 g of isophorone diisocyanate was added, the viscosity increased rapidly. 1
After stirring at the same temperature for 0 minutes, a polyester (F) containing a small amount of urethane bonds was obtained as a slightly yellowish white wax at room temperature at a molecular weight of about 45,000. As in Example 2,
120 ° C, 1 between polyethylene terephthalate films
Pressing was performed at 0 kg / cm ² to obtain a 120 to 130 μ sheet on a disk. Sheets from polyester (E) could be easily torn by hand, but polyester (F) containing urethane linkages could not be torn manually. 5x5
The tensile strength of the transparent stretched film having a thickness of about 30 μm was 410 kg / cm ² .

[0011]

As described above, the present invention is constructed as described above, so that high-molecular-weight polyester containing no harmful heavy metals can be produced, and its use can be expanded to food-related packaging and the like.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C08G 18/42 C08G 63/685 C08G 63/91

Claims (1)

(57) [Claims] (1) In the process of synthesizing a saturated aliphatic polyester resin, 0.01 parts by weight based on 100 parts by weight of a resin formed.
A saturated aliphatic polyester having a number-average molecular weight of 5,000 or more whose terminal group is substantially a hydroxyl group by using 3 parts by weight of a germanium compound as a deglycolization catalyst; (b) the saturated aliphatic polyester in a molten state; Group polyester
A method for producing a polyester containing a urethane bond having a number average molecular weight of 10,000 or more, comprising adding 5 parts by weight of a diisocyanate.