JP2752876B2 - Polyester injection molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In recent years, plasticization of industrial parts, automobile parts, and household goods has progressed, while the waste of plastics used in large amounts has the potential to pollute rivers, oceans, and soil. , Has become a major social problem,
The emergence of biodegradable plastics for the prevention of this contamination has been anticipated and, for example, poly (3-hydroxybutyrate) produced by fermentation by microorganisms and starch, which is a natural polymer of a blend system, and general-purpose plastics And the like 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, since the natural polymer itself is not thermoplastic, there is a difficulty in moldability, and the use range 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 can also be used as high molecular weight compounds 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 automotive parts, automotive parts and household goods.

[0003] Most of these uses are injection molded articles of plastics, and high molecular weight polyesters usually used for them (herein, high molecular weight polyester means a number average molecular weight of 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, there is no idea that injection moldings are conventionally formed by using a biodegradable aliphatic polyester using an aliphatic type dicarboxylic acid as an aliphatic polyester.
One of the reasons why this idea of practical application has not been born is that, despite the fact that the injection molded article is required to have special molding conditions and molded article physical properties, even if it is crystalline, Most polyesters have a melting point of 100 ° C. or less, and have poor thermal stability upon melting.
More importantly, the properties of this aliphatic polyester, particularly the mechanical properties represented by tensile strength, show extremely poor values even at the same level of the number average molecular weight as the above polyethylene terephthalate, and the moldings requiring strength etc. It is thought that it was difficult to get the idea of obtaining something. Further, it is inferred that one of the reasons is that the research for further improving the physical properties by further increasing the number average molecular weight of the aliphatic polyester has not sufficiently progressed due to its 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. It is another object of the present invention to provide an injection molded article which is biodegradable as one of disposal means, that is, can be decomposed by microorganisms and is easily disposed after use.

[0005]

The present inventors have studied various reaction conditions for obtaining a polyester having a high molecular weight and sufficient practicality to form an injection-molded article, and as a result, the biodegradability was maintained. While obtaining a specific aliphatic polyester having a practically sufficient high molecular weight, the injection molded article molded therefrom has not only the above-mentioned biodegradability but also excellent thermal stability and mechanical strength. Thus, the present invention has been completed.

That is, the gist of the present invention is as follows.
6 ° C. and a melt viscosity of 6 × at a shear rate of 1000 sec ⁻¹
10 ^{2 to} 2 × 10 ⁴ poise, melting point 70 to 190
Injection molded product mainly composed of an aliphatic polyester at a temperature of ° C, (B) the aliphatic polyester having a number average molecular weight of 1
(A) an injection-molded article containing a urethane bond in an amount of 3,000 or more and 0.03 to 3.0% by weight, (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) an injection 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) a tensile strength of 200 to 100 parts by weight. In the injection molded articles of (A) to (C), which is 450 kg / cm ² . 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 an injection 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 the formation of the polyester prepolymer is unfavorable because it is not preferable, if the polyester prepolymer synthesized without a catalyst is used, the number average molecular weight is limited to about 2,500 even if it is high.

[0010] The polyester prepolymer for obtaining the aliphatic polyester used in the present invention has a number average molecular weight of 5,000 or more, which has a hydroxyl group at the terminal group containing the synthesis catalyst as described above. Preferably it has a relatively high molecular weight of 10,000 or more and a melting point of 6
A saturated aliphatic polyester having a temperature of 0 ° C. or higher, which is obtained by a catalytic reaction between glycols and a polybasic acid (or an anhydride thereof). When the number average molecular weight is less than 5,000,
With a small amount of coupling agent of 0.1 to 5 parts by weight used in the present invention, it is not possible to obtain a polyester for injection molded articles having good physical properties. Number average molecular weight is 5,000
A polyester prepolymer of 0 or more has a hydroxyl value of 30 or less and, even when used in a severe condition such as a molten state, is not affected by the remaining catalyst, and may form a gel during the reaction, even under severe conditions such as a molten state. And a high molecular weight polyester can be synthesized.

That is, the polymer constituting the injection 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 injection 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 a 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 includes (i) two carboxyl groups and one hydroxyl group.
And (ii) a type having one carboxyl group and two hydroxyl groups. However, from the viewpoint that a commercially available product can be easily obtained at low cost, (i) The malic acid which shares two carboxyl groups and one hydroxyl group in the same molecule of ()) is practically advantageous and is 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, (Iii) There is a type in which three hydroxyl groups and one carboxyl group are shared in the same molecule, and any type can be used, but a commercially available product is easily available at a low cost. From this, citric acid and tartaric acid are practically advantageous and are sufficient for the purpose 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, Examples thereof 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 relatively high molecular weight polyester prepolymer, 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, and examples thereof include the following 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 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 carried out under conditions in which the polyester prepolymer is in a homogeneous 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 specific melting properties for injection molding. That is, a temperature of 190 ° C. and a shear rate of 1000 sec ⁻¹
Is from 6 × 10 ² to 2 × 10 ⁴ poise, preferably from 2 × 10 ³ to 8 × 10 ³ poise, 2 × 1
0 ^{3 to} 6 × 10 ³ poise is particularly preferred. If it is less than 6 × 10 ² poise, the strength of the injection molded article becomes insufficient, and the injection molding becomes unstable. On the other hand, if it exceeds 2 × 10 ⁴ poise, injection molding becomes difficult, and the molded product is easily deformed due to residual strain. The melt viscosity was measured using a nozzle having a nozzle diameter of 1.0 mm and an L / D = 10 nozzle at a shear rate of 1000 sec ^-1 from a graph of the relationship between the shear rate measured at a resin temperature of 190 ° C. and the apparent viscosity. The viscosity was determined.

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 of the injection molded body is insufficient, and the injection molded body is easily deformed. In order to obtain a melting point of 70 ° C. or more, the melting point of the polyester prepolymer needs to be 60 ° C. or more.

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, 0.1 to 1.0% by weight is particularly preferred. The urethane bond amount is measured by C ₁₃ NMR and agrees well with the charged amount. When the amount is less than 0.03% by weight, the effect of increasing the molecular weight by urethane bonds is small, and the moldability is poor. When the amount exceeds 3.0% by weight, a gel is generated.

When using the above-mentioned aliphatic polyester to obtain the injection-molded article according to the present invention, if necessary, other lubricants such as antioxidants, heat stabilizers, ultraviolet absorbers, waxes, coloring agents, Needless to say, a crystallization accelerator, a reinforcing fiber and the like can be used in combination. That is, examples of the antioxidant include hindered phenol-based antioxidants such as pt-butylhydroxytoluene and pt-butylhydroxyanisole, and sulfur-based antioxidants such as distearylthiodipropionate and dilaurylthiodipropionate. And heat stabilizers such as triphenyl phosphite, trilauryl phosphite and trisnonyl phenyl phosphite; and ultraviolet absorbers such as pt-butylphenyl salicylate, 2-hydroxy-4-methoxybenzophenone, -Hydroxy-4-methoxy-2'-carboxybenzophenone, 2,4,5-trihydroxybutyrophenone and the like, as a lubricant, calcium stearate,
Examples of antistatic agents such as zinc stearate, barium stearate, and sodium palmitate include N, N-bis (hydroxyethyl) alkylamine, alkylamine, alkylallyl sulfonate, and alkyl sulfonate. Cyclododecane,
Tris- (2,3-dichloropropyl) phosphate,
Inorganic fillers such as pentabromophenyl allyl ether; calcium carbonate, silica, titanium oxide, talc, mica, barium sulfate, and alumina; crystallization promoters such as polyethylene terephthalate and poly-transcyclohexanedimethanol terephthalate; Examples thereof include inorganic fibers such as glass fiber, carbon fiber, boron fiber, silicon carbide fiber, graphite fiber, alumina fiber and amorphous fiber, and organic fibers such as aramid fiber.

The raw material mainly composed of the aliphatic polyester used in the present invention is molded by a usual injection molding machine, and the molding temperature is generally 170 to 240 ° C, preferably 180 to 230 ° C. Moldability is insufficient near the melting point, and when the temperature exceeds 240 ° C., deformation and thermal decomposition of the molded product are liable to occur.

The physical properties of the injection-molded article mainly containing the aliphatic polyester according to the present invention are as follows.
kg / cm ² , preferably 300 to 450 kg / cm ²
cm ² . When the tensile strength is 200 kg / cm ² or less, practical use is difficult.

[0027]

The present invention will be described below with reference to examples and comparative examples. In the following examples, the tensile strength was measured according to JIS.
Based on K-6758, the measurement was performed under the conditions of a tensile speed of 50 mm / min.

Example 1 A 700 L reactor was replaced with nitrogen, and 183 kg of 1,4-butanediol and 224 kg of succinic acid were charged. Raise the temperature under a nitrogen stream and
3.0 hours at 95 to 210 ° C.
The esterification reaction by dehydration condensation was performed under reduced pressure of 5 to 5 mmHg for 3.5 hours. The collected sample is
Acid value is 6.3 mg / g, number average molecular weight (Mn) is 5.2
The weight average molecular weight (Mw) was 10,100. Subsequently, 34 g of tetraisopropoxy titanium as a catalyst was added under a nitrogen stream at normal pressure. Raise the temperature,
The deglycol-reaction was performed at a temperature of 215 to 220 ° C. under a reduced pressure of 5 to 0.2 mmHg for 7.5 hours. The collected sample had a number average molecular weight (Mn) of 18,600 and a weight average molecular weight (Mw) of 50,300. The yield of this polyester (A1) is 339 kg excluding condensed water.
Met.

To a reactor containing 339 kg of polyester (A1), 4.07 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 270 kg. The obtained polyester (B1) is a slightly ivory-like white wax-like crystal having a melting point of 110 ° C. and a number average molecular weight (Mn) of 2
9,500, weight average molecular weight (Mw) of 127,00
0, MFR (190 ° C.) is 9.2 g / 10 min, viscosity of a 10% solution of orthochlorophenol is 170 poise, melt viscosity at 190 ° C. and shear rate 1000 sec ⁻¹ is 3.0 × 10 ³ poise. Was. The average molecular weight was measured using Shodex GPC System-11 (Showa Denko's gel chromatography), and the solvent was CF ₃ CO.
Ona in HIPPA 5 mmol solution, concentration 0.1 wt%, calibration curve is PMMA standard sample S manufactured by Showa Denko KK
The test was carried out on a HODEX Standard M-75.

The polyester (B1) is molded at a temperature of 210 ° C.
Then, an injection molded body was manufactured using an injection molding machine (IS-80A) manufactured by Toshiba Machine Co., Ltd. When the tensile strength of the obtained injection molded article was measured, it was found that the tensile strength was 370 kg / cm ² and the tensile elongation was 420%, which was extremely tough. In addition, when buried in soil for 5 months, it was decomposed into a state easily broken.

(Example 2) An injection molding machine (IS-80, manufactured by Toshiba Machine Co., Ltd.) was used to mold the polyester (B1) at a molding temperature of 180 ° C.
An injection molded article was produced using A). When the tensile strength of the obtained injection molded article was measured, the tensile strength was 390 kg /
It showed a value of cm ² and a tensile elongation of 400%, and was extremely tough. When this compact was buried in the soil for 5 months,
The state was the same as in Example 1.

Example 3 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.

To a reactor containing 333 kg of polyester (A2), 4.66 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 (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 000 sec ^-1 was 5.0 × 10 ³ poise.

Polyester (B2) is molded at 220 ° C.
Then, an injection molded body was manufactured using an injection molding machine (IS-80A) manufactured by Toshiba Machine Co., Ltd. When the tensile strength of the obtained injection-molded article was measured, it was found to be 390 kg / cm ² , tensile elongation 450%, and extremely tough. When this molded body was buried in the soil for 5 months, the molded product was decomposed and changed to a state where the shape was collapsed.

(Example 4) An injection molding machine (IS-80, manufactured by Toshiba Machine Co., Ltd.) was used at a molding temperature of 190 ° C for polyester (B2).
An injection molded article was produced using A). When the tensile strength of the obtained injection molded article was measured, the tensile strength was 410 kg /
It showed a value of cm ² and a tensile elongation of 430%, and was extremely tough. When this compact was buried in the soil for 5 months,
The same result as in Example 3 was obtained.

(Example 5) 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) is 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 10% solution of orthochlorophenol is 96 poise, temperature 190 ° C., shear rate 1000 s
The melt viscosity at ec ^-1 was 4.7 × 10 ³ poise.

Polyester (B3) is molded at 220 ° C.
Then, an injection molded body was manufactured using an injection molding machine (IS-80A) manufactured by Toshiba Machine Co., Ltd. When the tensile strength of the obtained injection-molded product was measured, it was found that the tensile strength was 365 kg / cm ² and the tensile elongation was 470%, which was extremely tough.

(Example 6) A 700 L reactor was purged with nitrogen, and then 200 kg of 1,4-butanediol, 250 kg of succinic acid and 2.8 kg of trimethylolpropane were used.
Was charged. The temperature was raised under a nitrogen stream,
At 4.5 ° C. for 4.5 hours, and further stop nitrogen for 15 to 5 mmH.
The esterification reaction by dehydration condensation was performed for 3.5 hours under reduced pressure of g. The collected sample had an acid value of 1.2.
mg / g, the number average molecular weight (Mn) was 8,990, and the weight average molecular weight (Mw) was 32,800. Subsequently, 37 g of tetraisopropoxytitanium as a catalyst was added under a nitrogen stream at normal pressure. Raise the temperature,
The deglycol-reaction was performed at 220 ° C. under a reduced pressure of 3 to 0.4 mmHg for 9 hours. The collected sample had a number average molecular weight (Mn) of 16,600 and a weight average molecular weight (M
w) was 46,800. This polyester (A
4) The yield is 367 theoretically excluding 76 kg of condensed water.
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 180 ° 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
The yield was 310 kg. The obtained polyester (B4) is a slightly ivory-like white wax-like crystal having a melting point of 110 ° C. and a number average molecular weight (Mn) of 27,1.
00, weight average molecular weight (Mw) is 148,000 (Mw
/ Mn = 5,5), MFR (190 ° C.) is 7.7 g / 1.
At 0 minute, at a temperature of 190 ° C. and a shear rate of 1000 sec ^−1, the melt viscosity was 2.0 × 10 ³ poise. The average molecular weight was measured using Shodex GPC System-1.
1 (gel chromatography manufactured by Showa Denko KK), solvent was C
2 mmol solution of F ₃ COONa in HFIPA, concentration 0.
The calibration curve was 1% by weight, and a calibration curve was obtained using Showa Denko KK PMMA standard sample Shodex Standard M-75.

The polyester (B4) was molded at a molding temperature of 210 ° C.
Then, an injection molded body was manufactured using an injection molding machine (IS-80A) manufactured by Toshiba Machine Co., Ltd. When the tensile strength of the obtained injection-molded product was measured, it was found to be 390 kg / cm ² , tensile elongation 400%, and extremely tough. In addition, when buried in soil for 5 months, it was decomposed into a state easily broken.

(Comparative Example 1) Polyester (A1) was molded under the same conditions as in Example 1, but an injection molded article having sufficient strength could not be obtained.

[0045]

According to the present invention, a temperature of 190 ° C. and a shear rate of 10 are used.
The melt viscosity at 00 sec ^-1 is 6 × 10 ² to 2 × 10
^An injection-molded article made of an aliphatic polyester having ⁴ poises and having a melting point of 70 to 190 ° 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, An injection molded article using an aliphatic polyester obtained by reacting 1 to 5 parts by weight of a diisocyanate has biodegradability when buried in soil or the like, and has thermal stability and mechanical strength. It is excellent and is useful as industrial parts, automobile parts, food containers, beverage containers, garden pots, and the like.

Continuation of the front page (56) References JP-A-5-271377 (JP, A) JP-A-3-111418 (JP, A) JP-A-3-115418 (JP, A) JP-A-55-145734 (JP) JP-A-54-21496 (JP, A) JP-A-51-49591 (JP, A) US Patent 2,998,851 (US, A) US Patent 3,508,862 (US, A)

Claims (10)

(57) [Claims] 1. A temperature of 190 ° C. and a shear rate of 1000 sec.
^An injection molded article comprising an aliphatic polyester having a melt viscosity at ^-1 of 6 × 10 ² to 2 × 10 ⁴ poise and a melting point of 70 to 190 ° C. 2. An aliphatic polyester having a number average molecular weight of 1
The injection molded article according to claim 1, which is not less than 000 and contains 0.03 to 3.0% by weight of urethane bonds. 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 injection molded article according to claim 1 or 2, wherein the injection molded article is made of an aromatic polyester. 4. A tensile strength of 200 to 450 kg / cm ²
The injection molded article according to claim 1, wherein 5. An aliphatic polyester comprising a number average molecular weight (Mn) comprising an aliphatic glycol and an aliphatic dicarboxylic acid.
The injection 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 injection 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 injection 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.
An injection 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 injection-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,
The method according to claim 6, comprising one or more members selected from the group consisting of trimesic acid, propanetricarboxylic acid, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride and cyclopentanetetracarboxylic anhydride. Injection molding.