JP2662492B2 - Polyester hollow molded body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow molding having excellent thermal stability and mechanical strength using an aliphatic polyester having biodegradability, a practically sufficient high molecular weight and specific melting characteristics. About the body.

[0002]

2. Description of the Related Art In recent years, plastic molding containers have been developed for industrial use and household use in terms of productivity, versatility, fashionability, chemical resistance and rust prevention. Waste plastics, rivers,
It has the potential to contaminate the oceans and soil, and has become a major social problem. For the prevention of this pollution, the emergence of biodegradable plastics has been anticipated. (3-Hydroxybutyrate) and blends of starch, which is a blend-type natural polymer, and general-purpose plastics are known. However, the former has a drawback in that since the thermal decomposition temperature of the polymer is close to the melting point, the molding processability is inferior, and microorganisms create the raw material unit, which is very poor. In the latter case, since the natural polymer itself is not thermoplastic, moldability is difficult and the range of use is greatly restricted. On the other hand, although aliphatic polyesters are known to have biodegradability, they have hardly been used because a high molecular weight product sufficient for obtaining practical molded article properties cannot be obtained. Recently, ε-caprolactone has been found to have a high molecular weight by ring-opening polymerization, and has been proposed as a biodegradable resin. However, the melting point is as low as 62 ° C. ing. Glycolic acid and lactic acid also have high molecular weights obtained by ring-opening polymerization of glycolide and lactide, and are slightly used for medical fibers, etc. It has not been used in large quantities in hollow containers.

[0003] High-molecular-weight polyesters generally used for the molding of these industrial and household hollow molded articles (the high-molecular-weight polyester referred to here has a number average molecular weight of 10,10).
000 or more) is limited to polyethylene terephthalate, which is a condensate of terephthalic acid (including dimethyl terephthalate) and ethylene glycol. In some cases, 2,6-naphthalenedicarboxylic acid is used in place of terephthalic acid. However, in any case, attempts to impart biodegradability have not yet been reported. Therefore, it can be said that there is no idea that a hollow molded article is formed by using a biodegradable aliphatic polyester using an aliphatic type dicarboxylic acid as a conventional dicarboxylic acid, and that it is to be put to practical use. One of the reasons why the idea of this practical use has not been born is that, despite the fact that the plastic hollow molded body is required to have special molding conditions and physical properties of the molded article, even if it is crystalline, Most aliphatic polyesters have a melting point of 100 ° C. or less, and furthermore, have poor thermal stability upon melting, and more importantly, are represented by the properties of the aliphatic polyester, particularly its tensile strength. It is thought that the mechanical properties showed a remarkably inferior value even at the same level of the number average molecular weight as that of the polyethylene terephthalate, and it was thought that it was difficult to give an idea to obtain a molded product requiring strength or the like. Further, it is inferred that one of the reasons is that the study for further improving the physical properties by further increasing the number average molecular weight of the aliphatic polyester has not sufficiently progressed due to poor thermal stability.

[0004]

SUMMARY OF THE INVENTION The present invention uses these aliphatic polyesters as components, has a practically sufficient high molecular weight, and is excellent in mechanical properties represented by thermal stability and tensile strength. Another object of the present invention is to provide a hollow molded body which is biodegradable as one of the disposal means, that is, can be decomposed by microorganisms or the like, and is easily disposed after use.

[0005]

The present inventors have conducted various studies on the reaction conditions for obtaining a polyester having a moldability of a hollow molded article having a high molecular weight and sufficient practicality.
While retaining biodegradability, a specific aliphatic polyester having a practically sufficient high molecular weight is obtained, and the hollow molded article molded therefrom has not only the above biodegradability but also excellent heat stability and mechanical strength And completed the present invention.

That is, the gist of the present invention is as follows.
C. and a melt viscosity at a shear rate of 100 sec ^-1 is 3.0.
× 10 ^{3 to} 2.0 × 10 ⁵ poise, with a melting point of 70 to
A hollow molded article made of an aliphatic polyester at 190 ° C .; (B) an aliphatic polyester having a number average molecular weight of 10.0
(A) a hollow molded article containing 0.03 to 3.0% by weight of urethane bonds, and (C) an aliphatic polyester prepolymer having a number average molecular weight of 5,000 or more and a melting point of 60 ° C. or more. (A) or (B) a hollow molded article obtained by using an aliphatic polyester obtained by reacting 0.1 to 5 parts by weight of diisocyanate with 100 parts by weight, and (D) tensile strength at break. Not less than 320 kg / cm ² , elongation at break of 300% or more, rigidity of not less than 3000 kg / cm ² and notched Izod impact strength at 23 ° C. measured with a press of not less than 1.0 kg · cm / cm ² (A ), (B) or (C). Hereinafter, the contents of the present invention will be described in detail.

The aliphatic polyester referred to in the present invention is a trifunctional or tetrafunctional polyfunctional component comprising a glycol and a dicarboxylic acid (or an acid anhydride thereof) as two components or, if necessary, a third component. A polyester obtained by adding and reacting at least one polyfunctional component selected from a polyhydric alcohol, an oxycarboxylic acid and a polycarboxylic acid (or an acid anhydride thereof) as a main component; A polyester prepolymer having a relatively high molecular weight and having a hydroxyl group is prepared, and this is further increased in molecular weight by a coupling agent.

Conventionally, a low molecular weight polyester prepolymer having a number average molecular weight of 2,000 to 2,500 having a hydroxyl group as a terminal group is reacted with a diisocyanate as a coupling agent to form a polyurethane, Foams, paints and adhesives are widely used. However, polyester prepolymers used for these polyurethane foams, paints and adhesives are:
The maximum number average molecular weight that can be synthesized without a catalyst is 2,0
It is a low molecular weight prepolymer of 100 to 2,500, and in order to obtain practical physical properties as a polyurethane with respect to 100 parts by weight of the low molecular weight prepolymer, the amount of diisocyanate used is 10 to 20 parts by weight. When such a large amount of diisocyanate is added to a low-molecular-weight polyester melted at 150 ° C. or higher, gelation occurs and a normal melt-moldable resin cannot be obtained.
Therefore, a polyester obtained by using such a low molecular weight polyester prepolymer as a raw material and reacting a large amount of diisocyanate cannot be used as a raw material for a hollow molded article of the present invention.

As in the case of polyurethane rubber, a method of converting a hydroxyl group into an isocyanate group by adding a diisocyanate and further increasing the number average molecular weight with a glycol may be considered. As described above, the amount is 10 parts by weight or more based on 100 parts by weight of the prepolymer, so that practical properties are obtained. If a polyester prepolymer having a relatively high molecular weight is to be used, the heavy metal catalyst required for the synthesis of the prepolymer significantly promotes the reactivity of the isocyanate group used in the above amount, resulting in poor storage stability, crosslinking reaction, and branching. Since it is not preferable to use a polyester prepolymer synthesized without a catalyst as a polyester prepolymer, the number average molecular weight is limited to about 2,500 at the highest even if it is high.

The polyester prepolymer for obtaining the aliphatic polyester used in the present invention has a terminal group containing a catalyst for the synthesis substantially having a hydroxyl group.
The number average molecular weight is 5,000 or more, preferably 10,000
This is a saturated aliphatic polyester having a relatively high molecular weight of 0 or more and a melting point of 60 ° C. or more, and is obtained by a catalytic reaction between glycols and a polybasic acid (or anhydride thereof).
When the number average molecular weight is less than 5,000, for example, about 2,500, a small amount of coupling agent of 0.1 to 5 parts by weight used in the present invention can provide a polyester for a hollow molded article having good physical properties. Can not do. A polyester prepolymer having a number average molecular weight of 5,000 or more has a hydroxyl value of 30 or less, and is not affected by the remaining catalyst even under severe conditions such as a molten state by using a small amount of a coupling agent. A high molecular weight polyester can be synthesized without generating a gel therein.

That is, the polymer constituting the hollow molded article of the present invention is a polyester prepolymer composed of an aliphatic glycol and an aliphatic dicarboxylic acid and having a number average molecular weight (Mn) of 5,000 or more, preferably 10,000 or more, For example, it has a structure linked via a urethane bond derived from diisocyanate as a coupling agent. Furthermore, in the polymer constituting the hollow molded article of the present invention, the polyester prepolymer has a long-chain branch derived from a polyfunctional component, and this has a urethane bond derived from diisocyanate as a coupling agent, for example. It has a structure that is linked via When an oxazoline, a diepoxy compound, or an acid anhydride is used as a coupling agent, the polyester prepolymer takes a chain structure via an ester bond.

The glycols used include, for example, ethylene glycol, 1,4-butanediol, 1,6
-Hexanediol, decamethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol and the like. Ethylene oxide can also be used. These glycols may be used in combination.

Polybasic acids (or their anhydrides) which react with 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 acid anhydrides thereof) may be used in combination.

(Third component) In addition to these glycols and dicarboxylic acids, if necessary, as a third component, a trifunctional or tetrafunctional polyhydric alcohol, oxycarboxylic acid and polycarboxylic acid ( Or its acid anhydride)
And at least one kind of polyfunctional component selected from the above may be reacted. By adding this third component, long-chain branching occurs in the molecule, so that the molecular weight is increased and Mw is increased.
/ Mn increases, that is, the molecular weight distribution increases,
Desirable properties can be imparted to film forming and the like. The amount of the polyfunctional component to be added is 0.1 in the case of trifunctional with respect to 100 mol% of all components of the aliphatic dicarboxylic acid (or an acid anhydride thereof) so that there is no danger of gelling. 1 to 5 mol%, and 0.1 to
3 mol%.

(Polyfunctional Component) Examples of the polyfunctional component used as the third component include trifunctional or tetrafunctional polyhydric alcohols, oxycarboxylic acids and polycarboxylic acids. The trifunctional polyhydric alcohol component is typically trimethylolpropane, glycerin or its anhydride, and the tetrafunctional polyhydric alcohol component is pentaerythritol.

The trifunctional oxycarboxylic acid component comprises (i)
There are two types of carboxyl groups and one hydroxyl group in the same molecule, and (ii) a type having one carboxyl group and two hydroxyl groups. In terms of being available at
Malic acid which shares two carboxyl groups and one hydroxyl group in the same molecule of (i) is practically advantageous and sufficient for the purpose of the present invention. There are the following three types of tetrafunctional oxycarboxylic acid components. That is, (i)
A type sharing three carboxyl groups and one hydroxyl group in the same molecule, (ii) a type sharing two carboxyl groups and two hydroxyl groups in the same molecule, and (iii) three types. There is a type in which a hydroxyl group and one carboxyl group are shared in the same molecule, and any type can be used. However, from the viewpoint that a commercially available product can be easily obtained at low cost, citric acid And
Tartaric acid is practically advantageous and is sufficient for the purposes of the present invention. As the trifunctional polycarboxylic acid (or an acid anhydride thereof) component, for example, trimesic acid, propanetricarboxylic acid, or the like can be used. From the practical viewpoint, trimellitic anhydride is advantageous. Is enough. There are various types of tetrafunctional polycarboxylic acids (or acid anhydrides thereof) in the literature, such as aliphatic, cycloaliphatic, and aromatic, but from the viewpoint that commercially available products can be easily obtained, for example, Examples include pyromellitic anhydride, benzophenonetetracarboxylic anhydride, and cyclopentanetetracarboxylic anhydride, which are sufficient for the purpose of the present invention.

These glycols and polybasic acids are mainly composed of aliphatic compounds, but may be used in combination with small amounts of other components such as aromatic compounds. However, if other components are introduced, the biodegradability deteriorates, so the content is 20% by weight or less, preferably 10% by weight or less, more preferably 5% by weight or less. The polyester prepolymer for aliphatic polyester used in the present invention has a terminal group substantially a hydroxyl group,
For that purpose, the glycols and polybasic acids (or acid anhydrides) used in the synthesis reaction need to be used in a slightly excessive amount of glycols.

In order to synthesize a polyester prepolymer having a relatively high molecular weight, it is necessary to use a deglycol-reaction catalyst during the deglycolization reaction following the esterification. 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. Examples of these include diacetacetoxyoxytitanium ("Narcem Titanium" manufactured by Nippon Chemical Industry Co., Ltd.), tetraethoxytitanium, tetrapropoxytitanium, tetrabutoxytitanium and the like. The use ratio of the titanium compound is 0.001 to 100 parts by weight of the polyester prepolymer.
1 part by weight, desirably 0.01 to 0.1 part 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 number average molecular weight is 5,000 or more,
Desirably, a coupling agent is used to further increase the number average molecular weight of the polyester prepolymer in which 10,000 or more terminal groups are substantially hydroxyl groups. Examples of the coupling agent include diisocyanates, oxazolines, diepoxy compounds, acid anhydrides, and the like.
Particularly, diisocyanate is preferable. In the case of an oxazoline or diepoxy compound, it is necessary to react a hydroxyl group with an acid anhydride or the like and convert the terminal to a carboxyl group before using a coupling agent. The type of diisocyanate is not particularly limited, for example, 2,4.
-Tolylene diisocyanate, a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, xyl hydride Examples thereof include range isocyanate, hexamethylene diisocyanate, and isophorone diisocyanate, and hexamethylene diisocyanate is particularly preferable in terms of the hue of the formed resin, reactivity when adding polyester, and the like.

The amount of the coupling agent 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 polyester prepolymer. If the amount is less than 0.1 part by weight, the coupling reaction is insufficient, and if it exceeds 5 parts by weight, gelation is liable to occur.

The addition is desirably performed under conditions where the polyester prepolymer is in a uniform molten state and can be easily stirred. It is not impossible to add to the solid polyester prepolymer and melt and mix through an extruder, but it is added to the aliphatic polyester production equipment or to the molten polyester prepolymer (for example, in a kneader). It is practical to do.

The aliphatic polyester used in the present invention is required to have a specific melting property in order to perform hollow molding. That is, the melt viscosity at a temperature of 190 ° C. and a shear rate of 100 sec ⁻¹ is 3.0 × 10 ^{3 to} 2.0 × 10 ⁵ poise, preferably 1.2 × 10 ^{4 to} 3.0 × 10 ⁴ poise. 6 × 10 ^{4 to} 2.6 × 10 ⁴ poise is particularly preferred. If it exceeds 2.0 × 10 ⁵ poise, a parison having a good appearance cannot be obtained, and if it is less than 3.0 × 10 ³ poise, a drawdown property is poor and a good thick product cannot be obtained.

Further, the melting point of the aliphatic polyester used in the present invention needs to be 70 to 190 ° C, more preferably 70 to 150 ° C, and particularly preferably 80 to 135 ° C. If the temperature is lower than 70 ° C., the heat resistance is insufficient, and deformation during use becomes a problem.
Those exceeding 0 ° C. are difficult to manufacture. In order to obtain a melting point of 70 ° C. or more, the melting point of the polyester prepolymer is 60
It is necessary to be higher than or equal to ° C.

When the aliphatic polyester used in the present invention contains a urethane bond, the amount of the urethane bond is 0.03 to 3.0% by weight, preferably 0.05 to 2.0% by weight, and more preferably 0.1 to 2.0% by weight. Particularly preferred is 1 to 1.0% by weight.
The urethane bond amount is measured by C ₁₃ NMR and agrees well with the charged amount. If it is less than 0.03% by weight, the effect of increasing the molecular weight by the urethane bond is small, and the molding processability is poor,
If it exceeds 3.0% by weight, a gel is generated.

When using the above aliphatic polyester to obtain the hollow molded article according to the present invention, if necessary, other lubricants such as antioxidants, heat stabilizers, ultraviolet absorbers, waxes, coloring agents ( It goes without saying that a coloring pellet, a dry color, a master batch, etc.), a foaming agent, a crystallization accelerator, a reinforcing fiber and the like can be used in combination. That is, as antioxidants, pt-butylhydroxytoluene, p-
hindered phenolic antioxidants such as t-butylhydroxyanisole, distearylthiodipropionate,
As heat stabilizers such as sulfur-based antioxidants such as dilaurylthiodipropionate, triphenyl phosphite,
Examples of ultraviolet absorbers such as trilauryl phosphite and trisnonylphenyl phosphite include pt-butylphenyl salicylate, 2-hydroxy-4-methoxybenzophenone, and 2-hydroxy-4-methoxy-2′-.
Examples of lubricants such as carboxybenzophenone and 2,4,5-trihydroxybutyrophenone include calcium stearate, zinc stearate, barium stearate, and sodium palmitate. Antistatic agents include N, N
-Bis (hydroxyethyl) alkylamine, alkylamine, alkylallyl sulfonate, alkyl sulfonate, etc., as a flame retardant, hexabromocyclododecane, tris- (2,3-dichloropropyl) phosphate, pentabromophenyl allyl ether, etc. As an inorganic filler, calcium carbonate, silica, titanium oxide, talc, mica, barium sulfate, alumina, etc., as a crystallization accelerator, polyethylene terephthalate, poly-transcyclohexane dimethanol terephthalate, etc., as a reinforcing fiber, glass fiber, carbon Inorganic fibers such as fibers, boron fibers, silicon carbide fibers, graphite fibers, alumina fibers, and amorphous fibers; and organic fibers such as aramid fibers.

The raw material containing an aliphatic polyester as a main component used in the hollow molded article according to the present invention is obtained by a direct hollow molding method, an accumulator hollow molding method, an injection hollow molding method, a stretch hollow molding method, or a multilayer hollow molding method. Become a hollow product. In the case of direct blow molding, the temperature of the parison resin to be plasticized is 70 to 220 ° C, preferably 160 ° C.
To 200 ° C, more preferably 170 ° C to 190 ° C
It is. In the vicinity of the melting point, inconvenience occurs because the resin is not sufficiently plasticized and becomes unmelted, and the parison has a rough skin phenomenon. On the other hand, when the temperature exceeds 220 ° C., the drawdown property is deteriorated, which is inconvenient. Here, the drawdown property means the ratio of the time when the parison length reaches 60 cm and 12 cm when extruded at a shear rate of 100 sec ^-1 at the tip of the die and the core.

[0027]

The present invention will be described below with reference to examples and comparative examples. (Example 1) After replacing a 700 L reactor with nitrogen,
183 kg of 1,4-butanediol, 224 k of succinic acid
g. The temperature is increased under a nitrogen stream, and
At 0 ° C. for 3.5 hours, further stop nitrogen, and then 20 to 2 mm
The esterification reaction by dehydration condensation was performed under reduced pressure of Hg for 3.5 hours. The collected sample had an acid value of 9.
The number average molecular weight (Mn) was 5,160, and the weight average molecular weight (Mw) was 10,670. Subsequently, 34 g of tetraisopropoxy titanium as a catalyst was added under a nitrogen stream at normal pressure. Raise the temperature to 215
5.5 at 220 to 220 ° C under a reduced pressure of 15 to 0.2 mmHg.
The deglycol reaction was performed for a time. The collected sample had a number average molecular weight (Mn) of 16,800 and a weight average molecular weight (Mw) of 43,600. The yield of this polyester (A1) was 339 kg excluding condensed water.

To a reactor containing 339 kg of polyester (A1), 5.42 kg of hexamethylene diisocyanate was added, and a coupling reaction was carried out at 180 to 200 ° C. for 1 hour. The viscosity increased rapidly but no gelling occurred. Then, Irganox 1010 was used as an antioxidant.
1.70 kg (manufactured by Ciba Geigy) and 1.70 kg of calcium stearate as a lubricant were added, and stirring was further continued for 30 minutes. This reaction product was extruded into water with an extruder and cut into a pellet by a cutter. The yield of the polyester (B1) after vacuum drying at 90 ° C. for 6 hours was 300 kg.

The obtained polyester (B1) is a slightly ivory white wax-like crystal having a melting point of 110.
° C, the number average molecular weight (Mn) is 35,500, the weight average molecular weight (Mw) is 170,000, the MFR (190 ° C) is 1.0 g / 10 min, the viscosity of a 10% solution of orthochlorophenol is 230 poise, Temperature 190 ° C, shear rate 10
The melt viscosity at ⁰ sec ^-1 was 1.5 × 10 ⁴ poise. The average molecular weight is measured by Shodex GPC
System-11 (Showa Denko KK gel chromatography)), solvent of CF ₃ COONa HFIPA5mm
ol solution, concentration 0.1% by weight, calibration curve is Showa Denko KK
PMMA standard sample Shodex Standard
d Performed on M-75.

Using the polyester (B1), a hollow molded container was manufactured under the following conditions. Screw-φ50mm, L
A flat container having an average product thickness of 0.8 mm and a capacity of 400 ml was molded by a molding machine with / D = 26 and CR = 3. Molding resin temperature is 160 ° C, 180 ° C, 200 ° C, mold temperature is 20 ° C, blow pressure is 5kg / cm ² , cooling time is 1
The test was performed in 5 seconds.

Molding resin temperature 160 ° C., 180 ° C., 200
Drawdown property at ℃ is 2.5 or more and molding is good,
The outer surface of the product was good without melt fracture. Further, the obtained hollow molded container was filled with 100% of water and dropped from a height of 1.2 m at an ambient temperature of 5 ° C., but it was not broken even by repeated 10 drops, so that it can be used sufficiently for practical use. there were. When the product was subjected to a tensile test, the breaking strength was 320 kg / cm ² or more and the elongation was 300% or more. When the product was buried in soil for 5 months, biodegradability was recognized to the extent that water could not be filled.

Example 2 A 700 L reactor was purged with nitrogen, and 177 kg of 1,4-butanediol, 198 kg of succinic acid and 25 kg of adipic acid were charged. The temperature is increased under a nitrogen stream, and the temperature is increased to 190 to 210 ° C. for 3.5 hours.
2. Further stop nitrogen, and under a reduced pressure of 20 to 2 mmHg.
The esterification reaction by dehydration condensation was performed for 5 hours. The collected sample had an acid value of 9.6 mg / g, a number average molecular weight (Mn) of 6,100, and a weight average molecular weight (M
w) was 12,200. Subsequently, 20 g of tetraisopropoxytitanium as a catalyst was added under a nitrogen stream at normal pressure. Raise the temperature, 15 ~
The glycol removal reaction was performed under a reduced pressure of 0.2 mmHg for 6.5 hours. The collected sample is number average molecular weight (Mn)
Is 17,300, and the weight average molecular weight (Mw) is 46,
400. The yield of this polyester (A2) was 337 kg excluding condensed water.

4.66 kg of hexamethylene diisocyanate was added to a reactor containing 333 kg of polyester (A2), and a coupling reaction was carried out at 180 to 200 ° C. for 1 hour. The viscosity increased rapidly but no gelling occurred. Then, Irganox 1010 was used as an antioxidant.
1.70 kg (manufactured by Ciba Geigy) and 1.70 kg of calcium stearate as a lubricant were added, and stirring was further continued for 30 minutes. This reaction product was extruded into water with an extruder and cut into a pellet by a cutter. The yield of the polyester (B2) after vacuum drying at 90 ° C. for 6 hours was 300 kg.

The obtained polyester (B2) is a slightly ivory white wax-like crystal having a melting point of 103.
° C, number average molecular weight (Mn) is 36,000, weight average molecular weight (Mw) is 200,900, MFR (190 ° C) is 0.52 g / 10 min, and 10% of orthochlorophenol.
The solution has a viscosity of 680 poise, a temperature of 190 ° C. and a shear rate of 1.
The melt viscosity at 00 sec ^-1 was 2.2 × 10 ⁴ poise.

Example 1 using polyester (B2)
A hollow molded container was manufactured under the same conditions as described above. Molding resin temperature 1
The drawdown at 60 ° C, 180 ° C, and 210 ° C is 2.
The moldability was good at 5 or more, no melt fracture occurred on the outer surface of the product, and the result of the repeated drop test was good. When the obtained product was buried in soil for 5 months, the same result as in Example 1 was obtained.

(Example 3) A 700 L reactor was purged with nitrogen, and then 145 kg of ethylene glycol and succinic acid 2 were added.
51 kg and 4.1 kg of citric acid were charged. The temperature was raised under a nitrogen stream, and the esterification reaction by dehydration condensation was performed at 190 to 210 ° C. for 3.5 hours, and further with the nitrogen stopped, under a reduced pressure of 20 to 2 mmHg for 5.5 hours. The collected sample had an acid value of 8.8 mg / g, a number average molecular weight (Mn) of 6,800, and a weight average molecular weight (Mw) of 13,500. Subsequently, 20 g of tetraisopropoxytitanium as a catalyst was added under a nitrogen stream at normal pressure.
Raise the temperature to 15-0.2 at a temperature of 210-220 ° C.
The glycol removal reaction was performed under reduced pressure of mmHg for 4.5 hours. The sample collected had a number average molecular weight (Mn) of 3
3,400, and a weight average molecular weight (Mw) of 137,0
00. The yield of this polyester (A3) was 323 kg excluding condensed water.

3.23 kg of hexamethylene diisocyanate was added to a reactor containing 323 kg of polyester (A3), and a coupling reaction was carried out at 180 to 200 ° C. for 1 hour. The viscosity increased rapidly but no gelling occurred. Then, Irganox 1010 was used as an antioxidant.
1.62 kg (manufactured by Ciba Geigy) and 1.62 kg of calcium stearate as a lubricant were added, and stirring was further continued for 30 minutes. This reaction product was extruded into water with an extruder and cut into a pellet by a cutter. The yield of the polyester (B3) after vacuum drying at 90 ° C. for 6 hours was 300 kg.

The obtained polyester (B3) was a slightly ivory white wax-like crystal having a melting point of 96 ° C.
The number average molecular weight (Mn) is 54,000, the weight average molecular weight (Mw) is 324,000, and the MFR (190 ° C.) is 1.
1 g / 10 min, viscosity of a 10% solution of orthochlorophenol is 96 poise, temperature 190 ° C., shear rate 100 sec.
The melt viscosity at c ^-1 was 1.6 × 10 ⁴ poise.

A hollow molded container was produced in the same manner as in Example 1 except that the polyester (B3) was used and the molding resin temperature was 170 ° C., 180 ° C., and 200 ° C. Draw-down property at molding resin temperature of 170 ° C, 180 ° C, 200 ° C is 2.5 or more, good moldability, no melt fracture on the outer surface of the product, good results of repeated drop test Met. As a result of the tensile test of the product, the breaking strength is 3
20 kg / cm ² or more and elongation of 300% or more were good. When the obtained product was buried in the soil for 5 months, the product was decomposed and changed to a state where the shape of the container was lost.

Example 4 After purging a 700 L reactor with nitrogen, 200 kg of 1,4-butanediol, 250 kg of succinic acid and 2.8 kg of trimethylolpropane were used.
Was charged. The temperature is increased under a nitrogen stream, and
At 4.5 ° C. for 4.5 hours, and further stop nitrogen for 20 to 2 mmH.
The esterification reaction by dehydration condensation was performed under reduced pressure of 5.5 g for 5.5 hours. The collected sample has an acid value of 10.
The number average molecular weight (Mn) was 4,900, and the weight average molecular weight (Mw) was 10,000. Subsequently, 37 g of tetraisopropoxytitanium as a catalyst was added under a nitrogen stream at normal pressure. Raise the temperature to 210
8.0 to 220 ° C. under reduced pressure of 15 to 1.0 mmHg.
The deglycol reaction was performed for a time. The collected sample had a number average molecular weight (Mn) of 16,900 and a weight average molecular weight (Mw) of 90,300 (Mw / Mn = 5.
4). This polyester (A4) is theoretically condensed water 7
Excluding 6 kg, the yield was 367 kg.

3.67 kg of hexamethylene diisocyanate was added to a reactor containing 367 kg of polyester (A4), and a coupling reaction was performed at 160 to 200 ° C. for 1 hour. The viscosity increased rapidly but no gelling occurred. Then, Irganox 1010 was used as an antioxidant.
367 g (manufactured by Ciba Geigy) and 367 g of calcium stearate as a lubricant were added, and stirring was further continued for 30 minutes. This reaction product was extruded into water with an extruder and cut into a pellet by a cutter. 9
Polyester (B4) after vacuum drying at 0 ° C. for 6 hours
Was 350 kg.

The obtained polyester (B4) is a slightly ivory white wax-like crystal having a melting point of 110.
° C, the number average molecular weight (Mn) is 17,900, and the weight average molecular weight (Mw) is 161,500 (Mw / Mn = 9.
0), the MFR (190 ° C.) was 0.21 g / 10 min, the temperature was 180 ° C., and the melt viscosity at a shear rate of 100 sec ⁻¹ was 2.0 × 10 ⁴ poise. The measurement of the average molecular weight is
Shodex GPC System-11 (manufactured by Showa Denko KK, gel chromatography), and the solvent is CF ₃ COON
a 2 mmol solution of HFIPA, concentration: 0.1% by weight, and the calibration curve is PMMA standard sample Shod manufactured by Showa Denko KK
ex Standard M-75.

Using the polyester (B4), a hollow molded container was produced under the following conditions. Screw φ50mm,
A flat container having an average product thickness of 0.8 mm and a capacity of 400 ml was molded by a molding machine with L / D = 26 and CR = 3. Molding resin temperature is 160 ° C, 180 ° C, 200 ° C, mold temperature is 20 ° C, blow pressure is 5kg / cm ² , cooling time is 1
Performed in 5 seconds.

Molding resin temperature 160 ° C., 180 ° C., 200
Drawdown at 3.5 ° C. is 3.5 or more and molding is good.
The outer surface of the product was good without melt fracture. Further, the obtained hollow molded container was filled with 100% of water and dropped from a height of 1.2 m at an ambient temperature of 5 ° C. You. When the product was subjected to a tensile test, the breaking strength was 430 kg / cm ² or more and the elongation was 360% or more. When the product was buried in soil for 5 months, biodegradability was recognized to the extent that water could not be filled.

Comparative Example 1 Using the polyester (A1) in Example 1, the molding resin temperature was set to 140 ° C.
A hollow molded container was manufactured at ℃, but the drawdown property was 2.0 or less and molding was impossible.

[0046]

According to the present invention, a temperature of 190 ° C. and a shear rate of 10 are used.
The melt viscosity at ⁰ sec ^-1 is 3.0 × 10 ^{3 to} 2.0
X 10 ⁵ poise, a hollow molded article made of an aliphatic polyester having a melting point of 70 to 200 ° C, particularly 100 parts by weight of an aliphatic polyester prepolymer having a number average molecular weight of 5,000 or more and a melting point of 60 ° C or more. The hollow molded article made of aliphatic polyester obtained by reacting 0.1 to 5 parts by weight of diisocyanate has biodegradability when buried in soil or the like, even if it is incinerated. The calorific value of combustion is lower than that of polyethylene and polypropylene, and it is excellent in thermal stability and mechanical strength, and is useful as various containers such as detergents and cosmetics and industrial products.

Claims (10)

(57) [Claims] 1. A temperature of 190 ° C. and a shear rate of 100 sec ⁻¹
A hollow molded article made of an aliphatic polyester having a melt viscosity of 3.0 × 10 ^{3 to} 2.0 × 10 ⁵ poise and a melting point of 70 to 190 ° C. 2. An aliphatic polyester having a number average molecular weight of 1
2. The hollow molded article according to claim 1, which has a urethane bond of not less than 000 and 0.03 to 3.0% by weight. 3. A fat obtained by reacting 0.1 to 5 parts by weight of a diisocyanate with 100 parts by weight of an aliphatic polyester prepolymer having a number average molecular weight of 5,000 or more and a melting point of 60 ° C. or more. The hollow molded article according to claim 1 or 2, wherein the hollow molded article is made of an aromatic polyester. 4. A tensile breaking strength of at least 320 kg / cm ² , a breaking elongation of at least 300%, and a rigidity of 3000 kg / c.
The hollow molded article according to claim 1 to claim 3 the value of the notched Izod impact strength at 23 ° C. as measured by m ² or more and the press is 1.0kg · cm / cm ² or more. 5. An aliphatic polyester comprising a number average molecular weight (Mn) comprising an aliphatic glycol and an aliphatic dicarboxylic acid.
The hollow molded article according to claim 1 or 2, wherein a polyester prepolymer having a molecular weight of 5,000 or more has a structure linked via a urethane bond. 6. The aliphatic polyester is at least one polyfunctional selected from aliphatic glycols, aliphatic dicarboxylic acids and trifunctional or tetrafunctional polyhydric alcohols, oxycarboxylic acids and polycarboxylic acids or anhydrides thereof. Number average molecular weight (Mn) obtained by adding components and reacting
The hollow molded article according to claim 1 or 2, wherein a polyester prepolymer having a molecular weight of 5,000 or more has a structure linked via a urethane bond. 7. The polyester prepolymer is selected from the group consisting of ethylene glycol, 1,4-butanediol, 1,6-hexanediol, decamethylene glycol, neopentyl glycol and 1,4-cyclohexanedimethanol as glycol units. The dicarboxylic acid unit has a unit selected from the group consisting of succinic acid, adipic acid, suberic acid, sebacic acid, dodecanoic acid, succinic anhydride, and adipic anhydride.
Or the hollow molded article according to claim 6. 8. The polyester prepolymer according to claim 6, wherein the third component comprises, as a trifunctional or tetrafunctional polyhydric alcohol, at least one selected from the group consisting of trimethylolpropane, glycerin and pentaerythritol.
The hollow molded article according to the above. 9. The polyester prepolymer as a trifunctional or tetrafunctional oxycarboxylic acid as a third component,
1 selected from the group consisting of malic acid, citric acid and tartaric acid
The hollow molded article according to claim 6, comprising at least one species. 10. The polyester prepolymer as a trifunctional or tetrafunctional polycarboxylic acid as a third component,
7. The composition according to claim 6, comprising one or more selected from the group consisting of trimesic acid, propanetricarboxylic acid, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride and cyclopentanetetracarboxylic anhydride. Hollow molded body.