JPH06246767A - Polyester injection molded form - Google Patents

Abstract

PURPOSE:To provide an injection molded form such as an industrial component, an automotive member, a food vessel, a drinking vessel, a horticultural pot, etc., having a biodegradable properties when buried in soil, etc., excellent ther mal stability and mechanical strength. CONSTITUTION:An injection molded form is formed of aliphatic polyester having melted viscosity of 6X10<-2> G<4> poise at 1000sec<-1> of a shearing speed at 190 deg.C and a melting point of 70-190 deg.C. Thus, the form having biodegradable properties and excellent thermal stability and mechanical strength is obtained.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an injection molding excellent in thermal stability and mechanical strength using an aliphatic polyester which is biodegradable and has a practically sufficient high molecular weight and specific melting characteristics. Regarding the body

[0002]

2. Description of the Related Art In recent years, industrial parts, automobile parts, and household products have been made into plastics. On the other hand, plastic wastes, which are used in large quantities, have a possibility of contaminating rivers, oceans and soils. Has become a big social problem,
The advent of biodegradable plastics for the prevention of this pollution has long been awaited, and for example, poly (3-hydroxybutyrate) produced by a fermentation method using microorganisms and starch, which is a blend type natural polymer, and general-purpose plastics have already been demanded. Blends with are known. However, the former has a drawback that the raw material unit is very bad because the thermal decomposition temperature of the polymer is close to the melting point, the moldability is poor, and microorganisms produce it. Further, in the latter, since the natural polymer itself is not thermoplastic, moldability is difficult and the range of use is greatly restricted. On the other hand, it has been known that aliphatic polyester has biodegradability, but it has hardly been used because a high-molecular-weight substance sufficient to obtain practical physical properties of molded articles cannot be obtained. Recently, ε-caprolactone was found to have a high molecular weight by ring-opening polymerization and has been proposed as a biodegradable resin, but its melting point is as low as 62 ° C. and the raw material is expensive, so it is limited to special applications. ing. Glycolic acid and lactic acid can be obtained as a high molecular weight product by ring-opening polymerization of glycolide and lactide, and are used in medical fibers and the like, but they have melting points and decomposition temperatures close to each other, and have molding processability defects. It has not been used in large quantities for automobile parts, automobile parts and household products.

Most of these applications are injection moldings of plastics, and high molecular weight polyesters usually used for them (the high molecular weight polyesters referred to herein mean a number average molecular weight of 10,000 or more). It is no exaggeration to say that 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 was used instead of terephthalic acid, but none of them has reported the attempt to impart biodegradability to the present situation. Therefore, conventionally, there is no idea to mold an injection-molded article by using an aliphatic polyester having a dicarboxylic acid of an aliphatic type and having biodegradability and put it into practical use.
One of the reasons why the idea of practical application has not been born is that, even though the injection-molded body is required to have special molding conditions and physical properties of the molded product, even if it is crystalline, Most polyesters have a melting point of 100 ° C. or less, and moreover have poor thermal stability when melted,
More importantly, the properties of this aliphatic polyester, particularly the mechanical properties represented by the tensile strength, show a significantly inferior value even at the same level of the number average molecular weight as the above polyethylene terephthalate, and molding requiring strength etc. It is thought that it was difficult to think of how to get things. One of the reasons for this is that the research for further improving the number average molecular weight of the aliphatic polyester to improve its physical properties has not progressed sufficiently due to its poor thermal stability.

[0004]

DISCLOSURE OF THE INVENTION The present invention uses these aliphatic polyesters as its 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 an injection-molded article that is biodegradable as one of the means for disposal, that is, that can be decomposed by microorganisms and the like, and that can be easily disposed of after use.

[0005]

Means for Solving the Problems As a result of various studies on reaction conditions for obtaining a polyester having a high molecular weight and sufficient practicability for an injection-molded article, the biodegradability was maintained. In addition, it was found that a specific aliphatic polyester having a practically sufficient high molecular weight was obtained, and an injection-molded article molded from this had excellent thermal stability and mechanical strength as well as having the above-mentioned biodegradability. The present invention has been completed.

That is, the gist of the present invention is (A) a temperature of 190
Melt viscosity at shear rate of 1000 sec ^{-1 at} 6 ° C
10 ^{2 to} 2 × 10 ⁴ poises, melting point 70 to 190
The injection-molded product containing aliphatic polyester as the main component at (° C.), (B) the aliphatic polyester has a number average molecular weight of 1
(A) injection-molded article of (A) containing 30,000 or more and 0.03 to 3.0% by weight of a urethane bond, (C) 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) injection-molded article obtained by using 100 parts by weight of an aliphatic polyester obtained by reacting 0.1 to 5 parts by weight of diisocyanate, (D) tensile strength of 200 to The injection-molded article of (A) to (C) has a weight of 450 kg / cm ² . Hereinafter, the content of the present invention will be described in detail.

The term "aliphatic polyester" as used in the present invention means two components of glycols and dicarboxylic acid (or acid anhydride thereof), or, if necessary, a trifunctional or tetrafunctional polyfunctional compound as a third component. The main component is a polyester obtained by reacting with at least one polyfunctional component selected from a polyhydric alcohol, an oxycarboxylic acid and a polyvalent carboxylic acid (or an acid anhydride thereof), and the end of the molecule. A relatively high-molecular-weight polyester prepolymer having a hydroxyl group in is prepared, and this is further polymerized with a coupling agent.

Conventionally, a low molecular weight polyester prepolymer having a hydroxyl group as a terminal group and a number average molecular weight of 2,000 to 2,500 is reacted with diisocyanate as a coupling agent to obtain a polyurethane, a rubber, It is widely used as foam, paint and adhesive. However, the polyester prepolymers used in these polyurethane foams, paints and adhesives are
The maximum number average molecular weight that can be synthesized without catalyst is 20,
It is a low molecular weight prepolymer having an amount of 0 to 2,500, and the amount of diisocyanate used is 10 to 20 parts by weight for 100 parts by weight of this low molecular weight prepolymer in order to obtain practical physical properties as a polyurethane. When such a large amount of diisocyanate is added to the melted low molecular weight polyester at 150 ° C. or higher, gelation occurs and a usual melt-moldable resin cannot be obtained.
Therefore, a polyester obtained by reacting such a low molecular weight polyester prepolymer as a raw material with 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 adding a diisocyanate to convert a hydroxyl group into an isocyanate group and further increasing the number average molecular weight with glycol can be considered. As described above, in order to obtain practical physical properties, the amount is 10 parts by weight or more based on 100 parts by weight of the prepolymer, and there is the same problem as above. If a relatively high molecular weight polyester prepolymer is used, the heavy metal-based catalyst necessary for the synthesis of the prepolymer remarkably promotes the reactivity of the above-mentioned amount of the isocyanate group, resulting in poor storage stability, crosslinking reaction, and branching. If the polyester prepolymer synthesized without a catalyst is used because it causes generation, it is not preferable that the polyester prepolymer has a number average molecular weight of about 2,500.

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 contains a catalyst for the synthesis thereof and whose end group has a substantial hydroxyl group. It preferably has a relatively high molecular weight of 10,000 or more and a melting point of 6
It is a saturated aliphatic polyester at 0 ° C. or higher, and is obtained by catalytic reaction of glycols and polybasic acid (or its anhydride). When the number average molecular weight is less than 5,000,
With a small amount of the coupling agent of 0.1 to 5 parts by weight used in the present invention, it is not possible to obtain a polyester for an injection-molded article having good physical properties. Number average molecular weight is 5,000
A polyester prepolymer having a value of 0 or more has a hydroxyl value of 30 or less, and a small amount of a coupling agent is used, so that even under severe conditions such as a molten state, it is not affected by the remaining catalyst, so that a gel is formed during the reaction. Without, high molecular weight polyesters can be synthesized.

That is, the polymer constituting the injection-molded article of the present invention is a polyester prepolymer comprising 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 through a urethane bond derived from diisocyanate as a coupling agent. Furthermore, in the polymer constituting the injection-molded article of the present invention, the above 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. It has a structure chained via. When an oxazoline, diepoxy compound or acid anhydride is used as the coupling agent, the polyester prepolymer has a chain structure via an ester bond.

Examples of glycols used include ethylene glycol, 1,4-butanediol, and 1,6.
-Hexanediol, decamethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol and the like can be mentioned. Ethylene oxide can also be utilized. You may use these glycols together.

The polybasic acid (or its acid anhydride) which reacts with glycols to form an aliphatic polyester includes
Succinic acid, adipic acid, suberic acid, sebacic acid, dodecanoic acid, succinic anhydride, adipic anhydride, etc. are generally commercially available and can be used in the present invention. You may use together polybasic acid (or its acid anhydride).

(Third component) In addition to these glycols and dicarboxylic acids, a trifunctional or tetrafunctional polyhydric alcohol, oxycarboxylic acid and polycarboxylic acid (as a third component) may be added, if necessary. Or its acid anhydride)
At least one polyfunctional component selected from the above may be added and reacted. Addition of this third component causes branching of the long chain in the molecule, increasing the molecular weight and increasing the Mw.
/ Mn becomes large, that is, the molecular weight distribution becomes wide,
Desired properties can be imparted to film forming and the like. The amount of the polyfunctional component added is, in order to eliminate the risk of gelation, in the case of trifunctional with respect to 100 mol% of the total components of the aliphatic dicarboxylic acid (or its acid anhydride), it is 0. 1 to 5 mol%, and 0.1 to 4 in the case of tetrafunctionality
It is 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. Typical examples of the trifunctional polyhydric alcohol component are trimethylolpropane, glycerin and their anhydrides, and typical examples of the tetrafunctional polyhydric alcohol component are pentaerythritol. The trifunctional oxycarboxylic acid component has (i) two carboxyl groups and one hydroxyl group.
There are two types, one having one carboxyl group and the other having two hydroxyl groups in the same molecule, and (ii) commercially available products that are easily available at low cost. Malic acid, which shares two carboxyl groups and one hydroxyl group in the same molecule), 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 in which three carboxyl groups and one hydroxyl group are shared in the same molecule, (ii) a type in which two carboxyl groups and two hydroxyl groups are shared in the same molecule, (Iii) There is a type that shares three hydroxyl groups and one carboxyl group in the same molecule, and any type can be used, but commercial products are easily available at low cost. From the above, citric acid and tartaric acid are practically advantageous and are sufficient for the purpose of the present invention. As the trifunctional polyvalent carboxylic acid (or its acid anhydride) component, for example, trimesic acid, propanetricarboxylic acid, etc. can be used, but trimellitic anhydride is advantageous from the practical viewpoint, and for the purpose of the present invention. Is enough. There are various types of tetrafunctional polycarboxylic acid (or acid anhydride thereof) such as aliphatic, cycloaliphatic, and aromatic in the literature, but from the viewpoint of easy availability of commercially available products, for example, Examples include pyromellitic dianhydride, benzophenonetetracarboxylic acid anhydride, and cyclopentanetetracarboxylic acid anhydride, which are sufficient for the purpose of the present invention.

These glycols and polybasic acids are mainly of an aliphatic type, but a small amount of other components such as an aromatic type may be used together. However, if other components are introduced, biodegradability deteriorates, so the content is 20% by weight or less, preferably 10% by weight or less, and more preferably 5% by weight or less. The polyester prepolymer for the aliphatic polyester used in the present invention has a terminal group substantially a hydroxyl group,
For this purpose, the glycols and polybasic acid (or its acid anhydride) used in the synthesis reaction must be used in a somewhat excess amount.

The synthesis of relatively high molecular weight polyester prepolymers requires the use of a deglycolization catalyst during the deglycolization reaction following esterification. Examples of the deglycolization reaction catalyst include titanium compounds such as acetoacetoyl type titanium chelate compounds and organic alkoxy titanium compounds. These titanium compounds can be used in combination. Examples of these include diacetoacetoxyoxytitanium (“Narsem titanium” manufactured by Nippon Kagaku Sangyo Co., Ltd.), tetraethoxytitanium, tetrapropoxytitanium, tetrabutoxytitanium and the like. The titanium compound is used in an amount of 0.001 to 100 parts by weight of the polyester prepolymer.
It is 1 part by weight, preferably 0.01 to 0.1 part by weight.
The titanium compound may be added from the beginning of esterification or immediately before the deglycolization reaction.

Further, the number average molecular weight is 5,000 or more,
Coupling agents are preferably used to increase the number average molecular weight of polyester prepolymers having 10,000 or more end-groups which are substantially hydroxyl groups. Examples of the coupling agent include diisocyanate, oxazoline, diepoxy compound, acid anhydride, and the like.
Diisocyanate is particularly preferable. In the case of an oxazoline or diepoxy compound, it is necessary to react the hydroxyl group with an acid anhydride or the like to convert the terminal into a carboxyl group before using the coupling agent. The type of diisocyanate is not particularly limited, but 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 preferable from the viewpoint of the hue of the produced resin, the reactivity at the time of adding polyester, and the like.

The amount of these coupling agents 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 it is less than 0.1 part by weight, the coupling reaction is insufficient, and if it exceeds 5 parts by weight, gelation tends to occur.

It is desirable that the addition is carried out under the condition that the polyester prepolymer is in a uniform molten state and can be easily stirred. It is not impossible to add it to a solid polyester prepolymer and melt and mix it through an extruder, but add it to an aliphatic polyester production apparatus or to a molten polyester prepolymer (for example, in a kneader). It is practical to do so.

The aliphatic polyester used in the present invention is required to have specific melting characteristics for injection molding. That is, the temperature is 190 ° C., the shear rate is 1000 sec ^−1.
Has a melt viscosity of 6 × 10 ² to 2 × 10 ⁴ poise, preferably 2 × 10 ³ to 8 × 10 ³ poise, 2 × 1.
Especially preferred is 0 ^{3 to} 6 × 10 ³ poise. If it is less than 6 × 10 ² poise, the strength of the injection-molded article is 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 at a shear rate of 1000 sec ⁻¹ from a graph of the relationship between the shear rate and the apparent viscosity measured at a resin temperature of 190 ° C. with a nozzle diameter of 1.0 mm and a nozzle of L / D = 10. The viscosity was determined.

Further, the melting point of the aliphatic polyester used in the present invention is required 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 injection molded article lacks heat resistance and is easily deformed, and if the temperature exceeds 190 ° C, it is difficult to manufacture. In order to obtain a melting point of 70 ° C or higher, the polyester prepolymer needs to have a melting point of 60 ° C or higher.

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 0. 0.1 to 1.0% by weight is particularly preferable. The amount of urethane bond 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 moldability is poor, and if it exceeds 3.0% by weight, gel is generated.

When the above-mentioned aliphatic polyester is used to obtain the injection-molded article according to the present invention, if necessary, other lubricants such as antioxidants, heat stabilizers and ultraviolet absorbers, waxes, colorants, It goes without saying that a crystallization accelerator, a reinforcing fiber, etc. can be used in combination. That is, as antioxidants, hindered phenolic antioxidants such as pt-butylhydroxytoluene and pt-butylhydroxyanisole, sulfur-based antioxidants such as distearylthiodipropionate and dilaurylthiodipropionate. As heat stabilizers such as agents, triphenyl phosphite, trilauryl phosphite, trisnonyl phenyl phosphite, and the like, and as ultraviolet absorbers, pt-butylphenyl salicylate, 2-hydroxy-4-methoxybenzophenone, 2 -Hydroxy-4-methoxy-2'-carboxybenzophenone, 2,4,5-trihydroxybutyrophenone, etc., as a lubricant, calcium stearate,
Zinc stearate, barium stearate, sodium palmitate, etc., as the antistatic agent, N, N-bis (hydroxyethyl) alkylamine, alkylamine, alkylallyl sulfonate, alkyl sulfonate, etc., and hexabromo as a flame retardant. Cyclododecane,
Tris (2,3-dichloropropyl) phosphate,
Inorganic fillers such as pentabromophenyl allyl ether, calcium carbonate, silica, titanium oxide, talc, mica, barium sulfate, alumina and the like, crystallization accelerators such as polyethylene terephthalate, poly-transcyclohexanedimethanol terephthalate, reinforcing fibers Examples thereof include inorganic fibers such as glass fibers, carbon 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 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 if it exceeds 240 ° C., the molded product is likely to be deformed or thermally decomposed.

The physical properties of the injection-molded article containing an aliphatic polyester as a main component according to the present invention have a tensile strength of 200 to 450.
kg / cm ² , preferably 300 to 450 kg /
cm ² . If the tensile strength is 200 kg / cm ² or less, practical use is difficult.

[0027]

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

(Example 1) A 700-liter reactor was purged with nitrogen, and then 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 95-210 ℃, stop nitrogen further 1
The esterification reaction by dehydration condensation was performed for 3.5 hours under a reduced pressure of 5 to 5 mmHg. The sample collected is
Acid value 6.3 mg / g, number average molecular weight (Mn) 5,2
00, and the weight average molecular weight (Mw) was 10,100. Subsequently, 34 g of tetraisopropoxy titanium as a catalyst was added under a nitrogen stream under normal pressure. Raise the temperature,
The deglycolization reaction was carried out at a temperature of 215 to 220 ° C. under a reduced pressure of 5 to 0.2 mmHg for 7.5 hours. The sample collected 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.

4.07 kg of hexamethylene diisocyanate was added to a reactor containing 339 kg of polyester (A1), and a coupling reaction was carried out at 180 to 200 ° C. for 1 hour. The viscosity increased rapidly but no gelation occurred. Next, Irganox 1010 as an antioxidant
(Manufactured by Ciba Geigy) and 1.70 kg of calcium stearate as a lubricant were added, and stirring was continued for another 30 minutes. This reaction product was extruded into water with an extruder and cut into pellets with a cutter. The yield of polyester (B1) after vacuum drying at 90 ° C. for 6 hours was 270 kg. The obtained polyester (B1) was a slightly ivory-like white waxy crystal having a melting point of 110 ° C. and a number average molecular weight (Mn) of 2
9,500, weight average molecular weight (Mw) is 127,000
0, MFR (190 ° C.) was 9.2 g / 10 minutes, the viscosity of a 10% solution of orthochlorophenol was 170 poise, the melt viscosity at a temperature of 190 ° C. and a shear rate of 1000 sec ⁻¹ was 3.0 × 10 ³ poise. It was Measurement of average molecular weight, Shodex GPC System-11 (Showa Denko KK gel chromatography), the solvent is CF ₃ CO
ONa HFIPA 5 mmol solution, concentration 0.1% by weight, calibration curve is PMMA standard sample S manufactured by Showa Denko KK
It was performed on a hodex Standard M-75.

Molding temperature of polyester (B1) is 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 showed a value of a tensile strength of 370 kg / cm ² and a tensile elongation of 420%, and was extremely tough. Also, when it was buried in soil for 5 months, it decomposed into a state where it was easily destroyed.

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

(Example 3) A 700-liter reactor was purged with nitrogen, and then 177 kg of 1,4-butanediol, 198 kg of succinic acid, and 25 kg of adipic acid were charged. The temperature is raised under a nitrogen stream and the temperature is set at 190 to 210 ° C for 3.5 hours.
Further, nitrogen is stopped, and under reduced pressure of 20 to 2 mmHg, 3.
The esterification reaction by dehydration condensation was performed for 5 hours. The sample collected 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 tetraisopropoxy titanium as a catalyst was added under a nitrogen stream under normal pressure. Raise the temperature to 15-
The deglycol reaction was performed for 6.5 hours under a reduced pressure of 0.2 mmHg. The collected sample has a number average molecular weight (Mn)
Is 17,300, and the weight average molecular weight (Mw) is 46,
It was 400. The yield of this polyester (A2) was 337 kg when condensed water was removed.

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 gelation occurred. Next, Irganox 1010 as an antioxidant
(Manufactured by Ciba Geigy) and 1.70 kg of calcium stearate as a lubricant were added, and stirring was continued for another 30 minutes. This reaction product was extruded into water with an extruder and cut into pellets with a cutter. After vacuum drying at 90 ° C. for 6 hours, the yield of polyester (B2) was 300 kg.

The obtained polyester (B2) is a slightly ivory white waxy crystal and has 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 minutes, 10% of orthochlorophenol.
Viscosity of the solution is 680 poise, temperature 190 ℃, shear rate 1
The melt viscosity at 000 sec ⁻¹ was 5.0 × 10 ³ poise.

Molding temperature of polyester (B2) 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 showed a tensile strength of 390 kg / cm ² and a tensile elongation of 450%, and was extremely tough. When this molded body was buried in the soil for 5 months, it was decomposed and changed to a state where the shape was lost.

Example 4 Polyester (B2) was molded at a temperature of 190 ° C. at an injection molding machine (IS-80 manufactured by Toshiba Machine Co., Ltd.).
Injection moldings were 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 molded body was buried in the soil for 5 months,
The same result as in Example 3 was obtained.

(Example 5) A 700 L reactor was replaced with nitrogen, and then 145 kg of ethylene glycol and 2 parts of succinic acid 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 carried out at 190 to 210 ° C. for 3.5 hours, and further, nitrogen was stopped and the pressure was reduced to 20 to 2 mmHg under a reduced pressure 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 tetraisopropoxy titanium as a catalyst was added under a nitrogen stream under normal pressure.
Raise the temperature to 15-0.2 at a temperature of 210-220 ° C.
The deglycol reaction was performed for 4.5 hours under reduced pressure of mmHg. The sample collected has a number average molecular weight (Mn) of 3
3,400, and the weight average molecular weight (Mw) is 137,0
It was 00. The yield of this polyester (A3) was 323 kg when condensed water was removed.

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 gelation occurred. Next, Irganox 1010 as an antioxidant
1.62 kg (manufactured by Ciba Geigy) and 1.62 kg calcium stearate as a lubricant were added, and stirring was continued for another 30 minutes. This reaction product was extruded into water with an extruder and cut into pellets with a cutter. The yield of polyester (B3) after vacuum drying at 90 ° C. for 6 hours was 300 kg.

The polyester (B3) thus obtained was a slightly ivory white waxy 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 minutes, 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 x 10 ³ poise.

Molding temperature of polyester (B3) 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 showed values of a tensile strength of 365 kg / cm ² and a tensile elongation of 470%, and was tough.

(Example 6) After replacing a 700 L reactor with nitrogen, 200 kg of 1,4-butanediol, 250 kg of succinic acid and 2.8 kg of trimethylolpropane.
Was charged. The temperature is raised under a nitrogen stream to reach 195-210.
4.5 hours at ℃, stop nitrogen further, 15 ~ 5mmH
The esterification reaction by dehydration condensation was carried out for 3.5 hours under reduced pressure of g. The sample collected has 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 under normal pressure. Raise the temperature to a temperature of 215-
The deglycol reaction was performed at 220 ° C. under a reduced pressure of 3 to 0.4 mmHg for 9 hours. The sample collected had a number average molecular weight (Mn) of 16,600 and a weight average molecular weight (M
w) was 46,800. This polyester (A
The theoretical yield of 4) is 367 when 76 kg of condensed water is removed.
It was kg.

3.67 kg of hexamethylene diisocyanate was added to a reactor containing 367 kg of polyester (A4), and a coupling reaction was carried out at 160 to 180 ° C. for 1 hour. The viscosity increased rapidly but no gelation occurred. Next, Irganox 1010 as an antioxidant
367 g (manufactured by Ciba Geigy) and 367 g of calcium stearate as a lubricant were added, and stirring was continued for another 30 minutes. This reaction product was extruded into water with an extruder and cut into pellets with a cutter. 9
Polyester (B4) after vacuum drying at 0 ° C for 6 hours
The yield was 310 kg. The obtained polyester (B4) was a slightly ivory-like white waxy 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
The melt viscosity at 0 minutes, a temperature of 190 ° C., and a shear rate of 1000 sec ⁻¹ was 2.0 × 10 ³ poise. The average molecular weight is measured by Shodex GPC System-1.
1 (Showa Denko gel chromatography), solvent C
F ₃ HFIPA2mmol solution COONa, concentration 0.
1% by weight, and the calibration curve was performed using Showa Denko KK-made PMMA standard sample Shodex Standard M-75.

Molding temperature of polyester (B4) is 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 showed values of a tensile strength of 390 kg / cm ² and a tensile elongation of 400%, and was extremely tough. Also, when it was buried in soil for 5 months, it decomposed into a state where it was easily destroyed.

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

[0045]

According to the present invention, the temperature is 190 ° C. and the shear rate is 10
Melt viscosity at 00 sec ⁻¹ is 6 × 10 ² to 2 × 10
^An injection-molded article composed of an aliphatic polyester having a poise of ⁴ poise and a melting point of 70 to 190 ° C., in particular, 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 diisocyanate has biodegradability when buried in soil or the like, and has excellent thermal stability and mechanical strength. It is excellent and useful as industrial parts, automobile parts, food containers, beverage containers, pots for gardening, etc.

Claims (10)

[Claims] 1. A temperature of 190 ° C. and a shear rate of 1000 sec.
^-1 is an injection-molded article made of an aliphatic polyester having a melt viscosity of 6 × 10 ² to 2 × 10 ⁴ poise and a melting point of 70 to 190 ° C. 2. The aliphatic polyester has a number average molecular weight of 1.
The injection-molded article according to claim 1, wherein the injection-molded article has a content of 10,000 or more and contains 0.03 to 3.0% by weight of a urethane bond. 3. A fat obtained by reacting 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 with 0.1 to 5 parts by weight of diisocyanate. The injection-molded article according to claim 1 or 2, which comprises a group-polyester. 4. The tensile strength is 200 to 450 kg / cm ^2.
The injection-molded article according to any one of claims 1 to 3. 5. The number average molecular weight (Mn) of the aliphatic polyester comprising an aliphatic glycol and an aliphatic dicarboxylic acid.
The injection-molded article according to claim 1 or 2, wherein the polyester has a structure in which 5,000 or more polyester prepolymers are linked via urethane bonds. 6. The aliphatic polyester is at least one polyfunctional selected from an aliphatic glycol, an aliphatic dicarboxylic acid and a trifunctional or tetrafunctional polyhydric alcohol, an oxycarboxylic acid and a polycarboxylic acid or an anhydride thereof. Number average molecular weight (Mn) obtained by adding and reacting components
The injection-molded article according to claim 1 or 2, wherein the polyester has a structure in which 5,000 or more polyester prepolymers are linked via urethane bonds. 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. 6. 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.
Alternatively, the injection-molded article according to claim 6. 8. The polyester prepolymer as a third component, as a trifunctional or tetrafunctional polyhydric alcohol, one or more selected from the group consisting of trimethylolpropane, glycerin, pentaerythritol.
The injection-molded article according to. 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, containing at least one kind. 10. A polyester prepolymer as a trifunctional or tetrafunctional polycarboxylic acid as a third component,
7. The composition according to claim 6, containing at least one member selected from the group consisting of trimesic acid, propanetricarboxylic acid, trimellitic acid anhydride, pyromellitic acid anhydride, benzophenonetetracarboxylic acid anhydride and cyclopentanetetracarboxylic acid anhydride. Injection molded body.