JPH05179016A - Film molded by using and molding high-molecular weight aliphatic polyester - Google Patents

Abstract

PURPOSE:To obtain a film, excellent in thermal stability and having practically sufficient tensile strength. CONSTITUTION:The objective film is molded by using a high-molecular weight aliphatic polyester obtained by reacting (1) 100 pts.wt. polyester, prepared by reacting three components of (a) a glycol component (e.g. ethylene glycol) with (b) an aliphatic (including a cycloaliphatic) dicarboxylic acid (or its acid anhydride) component (e.g. succinic acid) and (c) a trifunctional hydroxycarboxylic acid component (e.g. malic acid) and having >=10,000 number-average molecular weight, terminal groups substantially composed of hydroxyl groups and >=60 deg.C melting point with (2) 0.1-3 pts.wt. polyfunctional isocyanate (e.g. hexamethylene diisocyanate) in a molten state at >= the melting point of the polyester.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a practically sufficient strength formed by using a high molecular weight aliphatic polyester having a viscosity and a branched structure at the time of melting required for film formation and having a urethane bond. The present invention relates to a film.

[0002]

2. Description of the Related Art High molecular weight polyesters conventionally used for forming films, molded articles, fibers and the like (the high molecular weight polyesters referred to here are those having a number average molecular weight of 10,000).
It is no exaggeration to say that the term "0 or more" is limited to polyethylene terephthalate, which is a condensate of terephthalic acid (including dimethyl ester) and ethylene glycol. In some cases, 2,6-naphthalenedicarboxylic acid was used instead of terephthalic acid, but an aliphatic type dicarboxylic acid was used to synthesize polyester, and this was molded into films, molded products, fibers, etc. It can be said that there are no such cases.

One of the reasons why it has not been put to practical use is that, even if it is crystalline, the melting point of the aliphatic polyester is almost 100 ° C. or less, and moreover, it is poor in thermal stability during melting. Depending on the polyester component, for example, when ethylene glycol is used as the glycol component, the melt viscosity is relatively low and the film forming property, for example, the film forming property by the inflation method is not always sufficient, and more importantly, The properties of aliphatic polyesters, especially the properties represented by tensile strength, are extremely inferior even at the same level of number average molecular weight as polyethylene terephthalate, and no practical use has been found. Studies that expect higher physical properties by increasing the number average molecular weight of aliphatic polyesters do not seem to have made sufficient progress due to poor thermal stability.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a film having excellent thermal stability during melting and practical mechanical strength.

[0005]

In order to increase the melt viscosity required for film formation, the present inventors have found that the ratio of the number average molecular weight (M _N ) of polyester to the weight average molecular weight (M _W ) ( As a result of repeated studies to maximize M _W / M _N ), a trifunctional oxycarboxylic acid component was used in combination as a polyester component, and a glycol component and an aliphatic (including cycloaliphatic) dicarboxylic acid (or its 0.1 to 3 parts by weight to 100 parts by weight of a polyester having a number average molecular weight of 10,000 or more, preferably 15,000 or more and having a terminal substantially a hydroxyl group, obtained by reacting with (an acid anhydride). Obtained by reacting the polyvalent isocyanate of the above in a molten state above the melting point of the polyester, the high molecular weight aliphatic polyester has a practically sufficient high molecular weight, and has a viscosity at the time of melting necessary for film formation. The present invention has completed the present invention by finding that the film formed from the film has excellent thermal stability and practical mechanical strength.

That is, the present invention provides (1) (a) glycol component, (b) aliphatic (including cycloaliphatic) dicarboxylic acid (or acid anhydride thereof) component, and (c) trifunctional oxycarboxylic acid. The number average molecular weight obtained by reacting three components is 10,0.
100 parts by weight of polyester having a melting point of 60 ° C. or higher and having a hydroxyl group of 00 or more and a terminal group being substantially a hydroxyl group, (2) 0.1 to 100 parts by weight in a molten state of the polyester or higher.
Obtained by reacting 3 parts by weight of a polyvalent isocyanate,
The present invention relates to a film formed by using a high molecular weight aliphatic polyester.

When an appropriate amount of a trifunctional oxycarboxylic acid component is used in combination, a branched structure can be introduced into the polyester, and in combination with the addition and reaction of the polyvalent isocyanate, the weight average molecular weight is higher than the number average molecular weight. Can be significantly increased.

As the glycol component usable in the present invention, ethylene glycol, butanediol 1,4, hexanediol 1,6, 1,4-cyclohexanedimethanol and the like are generally used because the melting point of the polyester is 60 ° C. or more. In particular, ethylene glycol and butanediol 1,4 are suitable for the present invention.

The trifunctional oxycarboxylic acid component is (i)
A type having one hydroxyl group and two carboxyl groups in the same molecule, (ii) a type having two hydroxyl groups and one carboxyl group in the same molecule,
Although any of them can be used, malic acid (the following formula) is convenient and sufficient for the purpose of the present invention because it is commercially available, easily available, and low in cost.

[Chemical 1]

The proportion of the trifunctional oxycarboxylic acid component used is 5 mol% or less, 0.5 mol or less, based on 100 mol% of the glycol component or the aliphatic (including cycloaliphatic) dicarboxylic acid (or its acid anhydride) component. % Or more, preferably 1 to
It is 3 mol%. If the proportion of the trifunctional oxycarboxylic acid component used is less than 0.5 mol%, the meaning of addition is diminished, and if it exceeds 5 mol%, the risk of gelation during the reaction increases.

In the aliphatic (including cycloaliphatic) dicarboxylic acid (or acid anhydride thereof) component used in the present invention, a kind having an even number of methylene groups between carboxyl groups is kept at a melting point of 60 ° C. or higher. Is advantageous to. Examples of these are succinic acid, adipic acid, suberic acid, sebacic acid,
Dodecanoic acid (or its acid anhydride) is mentioned. Of course, these can be used together.

Polyester synthesis is generally carried out by esterification and deglycolization reaction, in which required amounts of inorganic and organic compounds of metals are used in combination. The number average molecular weight of the polyester thus obtained is
It should be 10,000 or more. When the number average molecular weight is less than 10,000, the amount of the polyvalent isocyanate added increases, and the risk of gelation increases rapidly.

Furthermore, the number average molecular weight of 10,000 or more produced, which is a constituent of the present invention, preferably 15,000.
There is no particular limitation on the polyvalent isocyanate added to the polyester whose 0 or more terminal groups are substantially hydroxyl groups to further increase the molecular weight, but the following types are commercially available. 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 preferable from the viewpoint of the hue of the produced resin and the reactivity when adding polyester. Further, a trifunctional isocyanate can also be used.

The addition amount of these polyvalent isocyanates depends on the molecular weight, but is 0.1 to 3 parts by weight, preferably 0.5 to 2 parts by weight, based on 100 parts by weight of the polyester. If the amount of polyvalent isocyanate added is less than 0.1 parts by weight, the effect of the present invention cannot be obtained, and if it is more than 3 parts by weight, there is a risk of gelation.

It is desirable that the addition is carried out under the conditions in which the polyester is in a uniformly molten state, does not contain a solvent, and can be easily stirred. Separately, it is not impossible to add it to solid polyester and melt and mix it through an extruder, but it is generally added in a polyester manufacturing apparatus or in a molten polyester (for example, in a kneader). Is practical.

The high molecular weight aliphatic polyester having a branched structure and containing a urethane bond of the present invention is formed into a film or sheet by a molding method such as an inflation method or a T-die method. Therefore, in the present invention, a film and a sheet are collectively referred to as a film.

In order to obtain a uniaxially or biaxially stretched film from a high molecular weight aliphatic polyester having a branched structure and containing a urethane bond, the polyester is produced in a flat or tubular shape from a conventional T-die or an annular die. ~ 2
The unstretched product obtained by extrusion molding at 00 ° C. is uniaxially or biaxially stretched. For example, in the case of uniaxial stretching, in the case of a film or sheet, it is stretched in the extrusion direction with a calendar roll or the like, or with a tenter in the direction orthogonal to the extrusion direction,
In the case of a tube, the tube is stretched in the extrusion direction or the circumferential direction.

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 with a roll and then in the transverse direction with a tenter or the like, and in the case of a tube, the extrusion direction of the tube. And in the circumferential direction of the tube, that is, in the direction perpendicular to the tube axis, either simultaneously or separately. The stretching temperature is room temperature to 90 ° C. and is selected as necessary. The draw ratio is appropriately selected depending on the application.

The uniaxially stretched or biaxially stretched film formed by using a high molecular weight aliphatic polyester having a branched structure and containing a urethane bond according to the present invention is extremely strong, and is a packaging film, agricultural mulch film. Is available for. The film of the present invention is also biodegradable.

When using the high molecular weight aliphatic polyester of the present invention, if necessary, lubricants, waxes,
Of course, a colorant, a filler and the like can be used together.

[0021]

EXAMPLES 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 fractionating condenser, a thermometer, and a gas introduction tube.
05 g, 354 g of succinic acid, 8 g (2 mol%) of malic acid, 0.06 g of tetraisopropyl titanate (about 30 ppm as titanium metal) were charged, and 200 to 20 in a nitrogen gas stream was introduced.
Esterified at 5 ° C, acid value 5.6, number average molecular weight 5,6
After synthesizing the polyester of 00, deglycolization reaction was performed at 220 ° C. under reduced pressure of 0.7 to 0.5 Torr for 3 hours, the number average molecular weight was 29,200, the weight average molecular weight was 90,
At 700, a polyester (a) having a M _W / M _N of about 3.1, a white wax and a melting point of about 97 ° C. was obtained.

500 g of polyester (a) was melted by heating in a heating kneader at 210 ° C. to 215 ° C., and 6 g (1.2 phr) of hexamethylene diisocyanate was added with stirring. The viscosity increased rapidly but did not gel.

The resulting polyester (A) having a branched structure and containing a urethane bond has a number average molecular weight of 39,30.
0, the weight average molecular weight was 281,000, the M _W / M _N was about 7.2, and it was a pale yellow wax and had a melting point of about 100 ° C.
In the melt flow measurement specified by JIS-K-7210, the amount of polyester (A) was 0.91 g / 10 min at a sample of 5 g, 190 ° C., and a load of 0.325 kg, but the total amount of polyester (a) was It spilled and a significant difference was observed.

The molecular weight is measured by Shodex GP.
According to C SYSTEM-11. Eluent CF ₃ COON
a, 5 mmol / HFIP (hexafluoroisopropanol, 1 l), column temperature 40 ° C., flow rate 1.0 mol / min,
Performed with a detector Shodex RI.

A polyester (A) film having a thickness of 70 μm produced by the T-die method at a temperature of 200 ° C.
Tensile strength when uniaxially stretched 3 times at 0 ° C is 14.4kg
At / mm ² , it was so strong that it could not be torn manually. However, when the polyester (a) was wound with a T-die, the polyester (a) was broken, and the desired film was not obtained.
When a film having a thickness of 75 to 80 [mu] obtained by press molding at 0 [deg.] C. was tried to be stretched, it was easily broken and a stretched film could not be obtained.

Example 2 Butanediol 1,4 was placed in a 1 liter separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas introduction tube.
200 g, succinic acid 189 g, adipic acid 58 g, malic acid 4.5 g (1.5 mol%), and titanium oxyacetylacetonate 0.05 g (about 18 ppm as metallic titanium) are charged at 205 to 210 ° C. in a nitrogen stream. After esterification to an acid value of 9.4 and a number average molecular weight of 6,900,
When the deglycolization reaction was carried out at 220 ° C. under reduced pressure of 0.5 to 0.6 Torr for 4 hours, the number average molecular weight was 32,000,
Polyester (b) having a weight average molecular weight of 93,800 and M _W / M _N of about 2.9 is a white wax and has a melting point of about 90.
Obtained at ° C.

5 g (1 phr) of isophorone diisocyanate was added while heating and melting 500 g of polyester (b) in a heating kneader at 210 ° C. to 215 ° C. The viscosity increased rapidly but did not gel.

The number average molecular weight of the obtained polyester (B) having a branched structure and containing a urethane bond is 44,000,
The weight average molecular weight is 317,000 and the M _W / M _N is about 7.
2. It was a pale yellow wax and had a melting point of about 94-95 ° C. In the melt flow measurement at a temperature of 190 ° C., a load of 2.16 kg and a sample amount of 5 g, the polyester (B) is 0.01 g /
In practice, almost no outflow was observed after 10 minutes, but the amount of polyester (b) was 4.0 g / 10 minutes.

Polyester molded as in Example 1
The film having a thickness of 70 μm from (B) was stretched 4 times at 80 ° C., and the tensile strength of the film was 13.9 kg / mm ² , which was extremely strong. Further, the polyester (B) is 200 to
It was confirmed that inflation molding was possible at 205 ° C. On the other hand, the polyester (b) broke when it was wound with a T-die and a film was not obtained, and thus was press-molded in the same manner as in Example 1 to obtain a film having a thickness of 75 to 80 μm, which was stretched. The film broke during stretching and the target film could not be obtained.

Example 3 In a 1-liter separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas inlet tube, 300 g of 1,4-cyclohexanedimethanol (manufactured by Eastman Chemical Company, USA) and dodecanoic acid were added. Charge 460 g, malic acid 9 g (about 3 mol%), tetrabutyl titanium 0.07 g (about 15 ppm as metallic titanium), and esterify in a nitrogen stream at 210 to 215 ° C., acid value 7.8, number average molecular weight 7 , 900, and under reduced pressure of 0.5 to 0.6 Torr, 220 to 225
The deglycol reaction was carried out at 0 ° C for 6 hours. Number average molecular weight 2
8,800, weight average molecular weight 90,200, M _W / M _N is about 3.2, pale ivory waxy form, melting point 72 ° C.
Polyester (d) of was obtained.

In a heating kneader, polyester (d) 50
7 g (1.4 phr) of xylylene diisocyanate was added while melting and kneading 0 g at 200 to 205 ° C. The viscosity increased rapidly but did not gel.

The obtained polyester (D) having a branched structure and containing a urethane bond has a yellowish brown waxy form and a melting point of 77.
At -78 ° C, the number average molecular weight was 39,800, the weight average molecular weight was 300,400, and M _W / M _N was about 7.5. Regarding the melt flow value of a sample amount of 5 g, 190 ° C. and a load of 2.16 kg, the polyester (D) was 0.01 g / 10 min or less, but the polyester (d) was 3.8 g / 10 min.

75 ~ obtained by press molding at 170 ° C
The tensile strength of the polyester (D) film obtained by stretching a 80 μ film at 50 ° C. 5 times was 12.7 kg / mm ² , and the elongation was 90 to 100%. On the other hand, the polyester (d) film obtained by press molding in the same manner as described above broke during the stretching, and the intended stretched film could not be obtained.

[0035]

The film of the present invention having a branched structure and formed from a high molecular weight aliphatic polyester containing a urethane bond has biodegradability, is excellent in thermal stability and tensile strength, and is packaged. It is useful as a film and agricultural mulch film.

Claims (2)

[Claims] 1. A component (1) (a) glycol component, (b) aliphatic (including cycloaliphatic) dicarboxylic acid (or acid anhydride thereof) component, and (c) trifunctional oxycarboxylic acid component. The number average molecular weight obtained by reacting
100 parts by weight of polyester having a melting point of 60 ° C. or higher and having a hydroxyl group of 00 or more and a terminal group being substantially a hydroxyl group, (2) 0.1 to 100 parts by weight in a molten state of the polyester or higher.
Obtained by reacting 3 parts by weight of a polyvalent isocyanate,
A film formed by using a high molecular weight aliphatic polyester. 2. The proportion of the trifunctional oxycarboxylic acid component used is 5 mol% or less with respect to 100 mol% of the glycol component or the aliphatic (including cycloaliphatic) dicarboxylic acid (or its acid anhydride) component. A film formed using the high molecular weight aliphatic polyester according to claim 1, which is 0.5 mol% or more.