JP3079713B2 - Film formed using polyester containing urethane bond - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an aliphatic (including a cycloaliphatic) having a practically sufficient high molecular weight and containing at least two urethane bonds in one molecule and having a melting point of 60 ° C. or more. The same applies to the following.) Polyester having a number average molecular weight of 10,000
The present invention relates to a film formed using the above polyester and having excellent thermal stability and mechanical strength.

[0002]

2. Description of the Related Art High-molecular-weight polyesters (hereinafter, referred to as "polyesters") conventionally used for molding films, fibers, and other molded articles.
The term "high molecular weight polyester" as used herein means that the number average molecular weight indicates 10,000 or more) is limited to polyethylene terephthalate which is a condensate of terephthalic acid (including dimethyl terephthalate) and ethylene glycol. It was no exaggeration to say.

There is an example in which 2,6-naphthalenedicarboxylic acid is used in place of terephthalic acid. However, there is no example in which an aliphatic type is used as a dicarboxylic acid to form a film, a fiber, or the like and put into practical use. It can be said. One of the reasons why it has not been put to practical use is that even if it is crystalline, the melting point of aliphatic polyester is almost 100 ° C. or less, and furthermore, it has poor thermal stability upon melting. What is important is that the properties of aliphatic polyesters, especially properties typified by tensile strength, show only extremely poor values even at the same level of number average molecular weight as polyethylene terephthalate,
It is nothing but practicality. It seems that the research for increasing the number average molecular weight of the aliphatic polyester to improve the physical properties has not sufficiently progressed due to its poor thermal stability.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a film having a practically sufficient high molecular weight, and excellent in thermal stability and tensile strength.

[0005]

SUMMARY OF THE INVENTION The present inventors have relied on a typical deglycolization reaction as a method for synthesizing a high molecular weight polyester, and have found that the aliphatic polyester having poor heat stability has a number average molecular weight of 20,000. It was found that it was extremely difficult to increase the above, and as a result of examining the reaction conditions for obtaining a film-forming polyester having sufficient practicality with a high molecular weight, the number average molecular weight was 5,000 or more, preferably 10 0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight of 100,000 parts by weight or more of a polyester having a terminal group substantially a hydroxyl group in a molten state at a temperature not lower than the melting point of the polyester. The isocyanate is reacted to have a number average molecular weight of 10,000 or more, preferably 2 or more.
A high molecular weight containing at least two urethane bonds per molecule having a viscosity of not less than 000, more desirably a 10% solution of orthochlorophenol (10 parts by weight of polyester, 90 parts by weight of orthochlorophenol) of 5 poise or more; It has been found that the above object can be achieved by synthesizing a polyester and forming it into a film, and has completed the present invention.

That is, according to the present invention, the number average molecular weight is 5,000.
0 or more, aliphatic polyester 100 having a melting point of 60 ° C. or more
The number average molecular weight obtained by reacting 0.1 to 5 parts by weight of diisocyanate in a molten state at a melting point or higher of the aliphatic polyester is not less than 10,000 and at least Both relate to a film formed using a polyester containing two urethane bonds.

Among the urethane-bonded polyesters used in the present invention, the viscosity of a 10% orthochlorophenol solution of the urethane-bonded polyester is 25.
It was found that when the temperature was 5 poise or more at ° C, the physical properties of the resulting film were excellent.

Conventionally, a polyester having a hydroxyl group at the terminal group and having a number average 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, Adhesives are widely used. However, the polyester used for the existing polyurethane has a number average molecular weight of 2,
It is a so-called prepolymer having a molecular weight of from 2,000 to 2,500. To obtain practical physical properties with respect to 100 parts by weight of this low-molecular-weight polyester, the amount of diisocyanate used depends on the molecular weight of the diisocyanate. Is at least 10 parts by weight
It must be as high as 5 to 20 parts by weight. However, when, for example, 10 parts by weight or more of diisocyanate is added to the molten polyester (almost 150 ° C. or more depending on the type), gelation always occurs regardless of whether the polyester is a low molecular weight polyester or a high molecular weight polyester. No resin that can be handled is obtained. In practice, the addition of more than 10 parts by weight of diisocyanate is carried out in the form of a solution dissolved in a solvent or, as in foam or RIM molding,
Whether to obtain the final cured resin at one time.

In the case of rubber, the hydroxyl group is converted to an isocyanate group (by adding diisocyanate), and the number average molecular weight is further increased with glycol. Thus, it is as large as 10 parts by weight or more. 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, even if the number average molecular weight is high, the limit is around 2,500.

In the present invention, the aliphatic polyester to be reacted with the diisocyanate must be a saturated polyester having a terminal group substantially a hydroxyl group and a number average molecular weight of 5,000 or more, preferably 10,000 or more. Must. If this is a low molecular weight polyester, for example, a number average molecular weight of about 2,500, a final resin having good physical properties can be obtained even when using 0.1 to 5 parts by weight of diisocyanate used in the present invention. Not only is it not possible, but also in the case of melt addition, there is a disadvantage that even in the case of 0.1 to 5 parts by weight, gelation may be caused during the reaction depending on the amount. Therefore, unless the terminal hydroxyl value is about 30 or less, a safe reaction cannot be performed. The aliphatic polyester having a number average molecular weight of 5,000 or more of the present invention necessarily has a hydroxyl value of this level or lower, and can safely be used under severe conditions such as a molten state by using a small amount of diisocyanate. High molecular weight polyesters can be synthesized. Therefore, the aliphatic polyester referred to in the present invention is calculated to have a number average molecular weight of at least 5,0.
It will contain one urethane bond per 00. Polyester containing a urethane bond having a number average molecular weight of 10,000 or more, desirably 20,000 or more obtained by the present invention can be formed into a tough film as long as it has a melting point of 60 ° C. or more and has crystallinity. Alternatively, it can be used as an agricultural multi-film.

The aliphatic polyester used in the present invention is synthesized from glycols and a polybasic acid (or an acid anhydride thereof).

The glycols used 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. These glycols may be used in combination.

The polybasic acids (or their anhydrides) which react with these glycols to form aliphatic 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.
Polybasic acids (or their acid anhydrides) may be used in combination.

The terminal group of the aliphatic polyester used in the present invention is substantially a hydroxyl group. For this purpose, the proportion of glycols and polybasic acids (or their anhydrides) used in the synthesis reaction is limited. Need to use some excess of glycols.

The method for synthesizing the aliphatic polyester is not particularly limited, and is generally increased to a high molecular weight by esterification followed by a glycol removal reaction. At the time of the deglycol reaction, it is necessary to use a deglycol reaction catalyst.

Examples of the deglycol-reaction catalyst include titanium compounds such as acetoacetoyl-type titanium chelate compounds and organic alkoxytitanium compounds.
These titanium compounds can be used in combination, but their necessity is small. Examples of these are diacetacetoxyoxytitanium (“Nasem Titanium” manufactured by Nippon Chemical Industry Co., Ltd.), tetraethoxytitanium, tetrapropoxytitanium, tetrabutoxytitanium, etc., all of which are commercially available and available. It is. The use ratio of the titanium compound is 0.001 to 1 with respect to 100 parts by weight of the polyester.
Parts by weight, desirably 0.01 to 0.1 parts by weight. The titanium compound may be added from the beginning of the esterification, or may be added immediately before the deglycolization reaction.

Further, the produced number average molecular weight which is a component of the present invention is 5,000 or more, preferably 10,000.
The diisocyanate added for further increasing the number average molecular weight to the aliphatic polyester having a hydroxyl group having 0 or more terminal groups is 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, and isophorone diisocyanate, particularly hexamethylene diisocyanate, are preferred from the viewpoint of the hue of the formed resin, the reactivity when adding polyester, and the like. The amount of these diisocyanates to be added is 0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the aliphatic polyester, depending on the molecular weight. The addition is desirably carried out under a condition in which the aliphatic polyester is in a homogeneous molten state, contains no solvent, and can be easily stirred. Separately, it is not impossible to add to a solid aliphatic polyester and melt and mix it through an extruder, but generally, it is in an aliphatic polyester production apparatus or in a molten aliphatic polyester (for example, in a kneader). Is practical.

The polyester containing a small amount of urethane bonds according to the present invention is formed into a film or a sheet by a molding method such as an inflation method and a T-die method. Therefore, in the present invention, a film and a sheet are referred to as a film.

In order to obtain a uniaxially or biaxially stretched film from a polyester containing a urethane bond, the polyester containing a urethane bond can be obtained from a conventional T-die or a cyclic die.
It is extruded into a flat or tube at 170 to 200 ° C., and the obtained unstretched product is monoaxially or biaxially stretched. For example, in the case of uniaxial stretching, in the case of a film or sheet, the film is stretched in the extrusion direction by a calendar roll or the like, or in a direction perpendicular to the extrusion direction by a tenter or the like, and in the case of a tube, in the extrusion direction or circumferential direction of the tube. Stretch.

In the case of biaxial stretching, in the case of a film or sheet, the extruded film or sheet is stretched in the longitudinal direction by a roll or the like, and then stretched in the transverse direction by a tenter or the like. And in the circumferential direction of the tube, that is, in the direction perpendicular to the tube axis, simultaneously or separately. The stretching temperature is from room temperature to 90 ° C., and is selected as necessary. The stretching ratio is appropriately selected depending on the application.

The uniaxially stretched or biaxially stretched film formed using the polyester containing a urethane bond of the present invention is tough and can be used for packaging films and agricultural multi-films.

When the polyester containing a urethane bond of the present invention is used, a lubricant, a wax, a coloring agent, a filler and the like can be used in combination, if necessary.

[0023]

EXAMPLES Next, examples will be shown below to facilitate understanding of the present invention.

Example 1 Ethylene glycol 2 was placed in a 1-liter separable flask equipped with a stirrer, a distillation condenser, a thermometer and a gas inlet tube.
10 g, 313 g of succinic acid, 44 g of adipic acid, and 0.06 g of tetraisopropoxytitanium were charged.
Esterification was advanced in a nitrogen stream at 10 ° C. to obtain an acid value of 9.0.
After that, the temperature is further increased to 210 to 215 ° C. and finally to 0.1.
A glycol removal reaction was performed for 10 hours at a reduced pressure of 6 Torr to synthesize a polyester (a) having a number average molecular weight of 15,500 and a melting point of 85 ° C. Next, 6 g of hexamethylene diisocyanate was added at a temperature of 215 ° C. to the remaining amount of the polyester (a) except for 5 g of the polyester (a) from the content. The viscosity increased rapidly but no gelling occurred.

The obtained polyester (A) containing a urethane bond was a slightly ivory white wax-like crystal having a melting point of 90 ° C. and a number average molecular weight of 32,000.

Measurement of the number average molecular weight was carried out by Shodex G
PC SYSTEM-11, eluent CF ₃ COONa,
Performed at 5 mmol / HFIP.

The viscosity of a 10% solution of the polyester (A) containing urethane linkages in orthochlorophenol was 18 poise.

The polyester (A) containing a urethane bond is melted at 200 ° C. and extruded with a T-die to form a film.
When a stretched film of 40 μm was manufactured and its tensile strength was measured, it showed a value of 13.9 to 16.1 kg / mm ² , which was extremely tough. However, a film made of polyester (a) produced in the same manner as polyester (A)
The film was cut during stretching, and the desired stretched film could not be obtained.

Example 2 A 2-liter separable flask equipped with a stirrer, a fractionating condenser, a thermometer and a gas inlet tube was charged with butanediol 1,4.
240 g, ethylene glycol 40 g, dodecane diacid 690 g, titanium oxyacetylacetonate 0.5 g
After esterification in a nitrogen stream at 205 to 210 ° C. to an acid value of 6.9, a glycol removal reaction is performed at a temperature of 210 to 215 ° C. and finally under a reduced pressure of 0.6 Torr,
Polyester (b) having a number average molecular weight of 16,800 and a melting point of about 68 ° C was synthesized. Next, the remaining amount of the polyester (b) excluding 5 g of the polyester (b) from the content
And at a temperature of 215 ° C., 12 g of isophorone diisocyanate
Was added. The viscosity increased rapidly but did not gel.

The obtained polyester (B) containing a urethane bond had a number average molecular weight of 34,100, was slightly ivory white wax, and had a melting point of about 70 ° C.

The viscosity of a 10% solution of the polyester (B) containing urethane linkages in orthochlorophenol is 134
Poise.

The polyester (B) containing a urethane bond was formed into a film in the same manner as in Example 1 and uniaxially stretched four times in the machine direction in the same manner as in Example 1 to obtain a film having a thickness of about 35 μm. Tensile strength is 10.1 to 13.4 kg / mm ² ,
The elongation percentage was 100 to 120%, which was extremely tough.
However, the film made of polyester (b) broke during the uniaxial stretching by a factor of four, and a stretched film was not obtained.

Example 3 Ethylene glycol 2 was placed in a 1-liter separable flask equipped with a stirrer, a distillation condenser, a gas inlet tube and a thermometer.
10 g, 606 g of sebacic acid and 0.4 g of tetraisopropoxytitanium were charged and esterified at a temperature of 205 to 210 ° C. to an acid value of 6.2, and finally under a reduced pressure of 0.5 Torr at a temperature of 210 to 215 ° C. Was subjected to a deglycol reaction for 10 hours to synthesize a polyester (c) having a number average molecular weight of 16,900 and a melting point of 72 ° C. Next, 5
At 210 ° C., 9 g of hydrogenated xylylene diisocyanate was added to the entire amount of polyester (c) except for g of polyester (c). The viscosity increased rapidly but did not gel.

The obtained polyester (D) containing a urethane bond was a slightly yellowish-brown white wax having a melting point of about 74 ° C. and a number average molecular weight of 36,000.

The viscosity of a 10% solution of the polyester (D) containing urethane bonds in orthochlorophenol was 13 poise.

The polyester (C) and the polyester (D) containing a urethane bond were formed into films in the same manner as in Example 1. When these films were uniaxially stretched in the machine direction in the same manner as in Example 1, the film made of polyester (c) was cut in the course of stretching four times, and a stretched film was not obtained. The film from (D) was not cut even when stretched 4 times, and the obtained stretched film having a thickness of about 35 μ had a tensile strength of 11.4 to 13.9 kg / mm ² and an elongation of about 100%.
It was a very tough film.

[0037]

The film molded from the polyester containing a urethane bond according to the present invention has biodegradability, excellent tensile strength and heat stability, and is useful as a packaging film and a multi-film for agricultural use. .

(56) References JP-A-61-195117 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 18/42 C08G 63/00-63/91 C08J 5 / 18

Claims (2)

(57) [Claims] 1. A diisocyanate having a number average molecular weight of 5,000 or more and a melting point of not less than 60 ° C. and 100 parts by weight of an aliphatic polyester having a melting point of not less than 0.1 to 5 parts by weight of an aliphatic polyester. And a film formed by using a polyester having a number average molecular weight of 10,000 or more and containing at least two urethane bonds in one molecule. 2. The film according to claim 1, wherein the viscosity of a 10% solution of a polyester containing urethane bonds in orthochlorophenol at 25 ° C. is 5 poise or more.