JPH06172620A - Polyester resin composition - Google Patents

Abstract

PURPOSE:To obtain a polyester resin composition for injection molding, excellent in mechanical strength represented by tensile strength and a low combustion calorific value even when disposed of after use and having the degradability with microorganisms and a sufficiently high molecular weight. CONSTITUTION:This resin composition is obtained by blending a polyester, synthesized from a glycol and an aliphatic dicarboxylic acid or its derivative and having >=10,000 molecular weight and >=70 deg.C melting point with a filter and regulating the melt viscosity at 190 deg.C temperature and 1000sec<-1> shearing rate to 10<3> to 10<5>P.

Description

Detailed Description of the Invention

[0001]

The present invention has a number average molecular weight of 10,
A polyester resin for injection molding that has a mechanical strength of less than 000 and has a small amount of heat when burned by blending an aliphatic polyester with a practically sufficient high molecular weight with a filler The present invention relates to a composition and a molded product thereof.

[0002]

2. Description of the Related Art High molecular weight polyesters conventionally used for molding injection moldings, films, fibers, and other molded articles (hereinafter, high molecular weight polyesters have a number average molecular weight of 10,000 or more). Shall be)
Polyethylene terephthalate, which is a condensate of terephthalic acid (including dimethyl terephthalate) and ethylene glycol, or terephthalic acid and butylene glycol
It is no exaggeration to say that it is limited to polybutylene terephthalate, which is a condensation product with 1,4.

Although there is an example in which 2,6-naphthalenedicarboxylic acid is used in place of terephthalic acid, there is no example in which a polymer using an aliphatic dicarboxylic acid in a dicarboxylic acid is molded and put into practical use. good.

One of the reasons why it has not been put to practical use is that, even if it is crystalline, the melting point of the aliphatic polyester is almost 100 ° C. or less, and moreover, the thermal stability upon melting is poor. , And more importantly, the properties of the aliphatic polyester, particularly the mechanical properties represented by the tensile strength, showed a significantly inferior value even at the same level of the number average molecular weight as polyethylene terephthalate, and the practicality was not found at all. Nothing else.

[0005] Researches for increasing the number average molecular weight of aliphatic polyesters to improve their physical properties seem to have not progressed satisfactorily due to their poor thermal stability.

[0006] Polyesters such as polyethylene terephthalate, which are generally used in large amounts in the industrial material field and packaging container field at present, are not biodegradable, so that they are not decomposed forever by simply discarding them after use, and rivers However, it has problems such as incineration for complete treatment because it pollutes the ocean and soil. But,
Although its calorific value is as low as 5,500 to 6,000 kcal / kg compared to polyethylene and polypropylene, the calorific value is still large compared to the average value of the calorific value of municipal waste, causing a large amount of wear in the incinerator. There is also.

[0007]

The present invention has a practically sufficient high molecular weight, excellent mechanical properties typified by tensile strength, and a small calorific value of combustion even if it is discarded after use. Furthermore, it is an object of the present invention to provide an aliphatic polyester resin composition for injection molding which can be decomposed by microorganisms and is easy to dispose, and an injection molded article thereof.

[0008]

The present invention relates to an aliphatic polyester having a number average molecular weight of at least 10,000 and a melting point of 70 ° C. or higher, which is synthesized from glycol and an aliphatic dicarboxylic acid or an acid derivative thereof. A polyester resin composition containing a filler and having a temperature of 190
Melt viscosity at ℃ and shear rate of 1,000 sec ^-1 is 1
The above object was achieved by developing a polyester resin composition for injection molding and a molded product thereof, which has a porosity of × 10 ³ to 1 × 10 ⁵ .

The aliphatic polyester referred to in the present invention is mainly composed of a polyester synthesized from glycols and an aliphatic dicarboxylic acid or its acid anhydride or an acid derivative such as a lower alkyl ester, and has a molecular weight of In order to make it sufficiently high, a relatively high molecular weight polyester prepolymer having hydroxyl groups at both ends is synthesized and then these prepolymers are further coupled by 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 a diisocyanate to form a polyurethane, which is used as a rubber, foam, paint or adhesive. Is widely practiced.

However, the polyester prepolymers used in these polyurethane type foams, paints and adhesives are low molecular weight prepolymers having a number average molecular weight of 2,000 to 2,500. The amount of diisocyanate used must be 10 to 20 parts by weight in order to obtain the practical physical properties of polyurethane based on 100 parts by weight of the low molecular weight prepolymer. 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 melt-moldable resin cannot be obtained.

Further, as in the case of polyurethane rubber,
A method of adding a diisocyanate to convert a hydroxyl group to an isocyanate group and further increasing the number average molecular weight with glycol can be considered, but the amount of the diisocyanate used is as described above. 10 parts by weight or more is necessary with respect to parts by weight. At this time, if a heavy metal-based catalyst is used for the synthesis of the polyester prepolymer,
The polyester prepolymer needs to be synthesized without a catalyst because it significantly promotes the reactivity with the isocyanate group, resulting in poor storage stability, cross-linking reaction, and branch formation.As a result, the number average molecular weight is high. The limit is about 2,500.

The polyester prepolymer for obtaining the aliphatic polyester used in the present invention has a terminal group obtained by reacting glycol with an aliphatic dicarboxylic acid or its derivative which is substantially a hydroxyl group, and has a number average molecular weight of Is a saturated aliphatic polyester having a relatively high molecular weight of 5,000 or more, preferably 10,000 or more, and a melting point of 60 ° C. or more.

If the number average molecular weight is less than 5,000, for example, about 2,500, a polyester having good physical properties cannot be obtained even if the amount of the coupling agent used is as small as 0.1 to 5 parts by weight. On the other hand, a polyester prepolymer having a number average molecular weight of 5,000 or more can be used to synthesize a high molecular weight polyester by using a small amount of a coupling agent without producing a gel during the reaction even under severe conditions such as a molten state. it can.

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.

Examples of the aliphatic dicarboxylic acid or its acid derivative which reacts with glycols to form an aliphatic polyester include succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedicarboxylic acid, succinic anhydride, adipic anhydride or There are lower alcohol esters such as dimethyl ester of these dibasic acids, which are commercially available and can be used in the present invention. You may use together dicarboxylic acid or its acid anhydride. These compounds may be previously made into low molecular weight esters and polymerized by a deglycol reaction.

These glycols and dicarboxylic 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, the 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 an aliphatic polyester used in the present invention has a terminal group which is substantially a hydroxyl group. For that purpose, use of glycols and dicarboxylic acids (or acid derivatives thereof) used in the synthetic reaction is used. The proportions require some excess use of glycols.

The synthesis of relatively high molecular weight polyester prepolymers requires the use of a deglycolization reaction 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 with respect to 100 parts by weight of the polyester prepolymer.
To 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.

As a result, the polyester prepolymer usually has a number average molecular weight of 5,000 or more, preferably 20,000.
It is more preferable that those having a melting point of 0 ° C. or higher and a melting point of 60 ° C. or higher can be easily obtained and have crystallinity.

In order to obtain the aliphatic polyester of the present invention, the number average molecular weight is more than 5,000, preferably 1.
Coupling agents are used to further increase the number average molecular weight of polyester prepolymers having 50,000 or more end groups which are substantially hydroxyl groups.

Examples of the coupling agent include diisocyanate, oxazoline, diepoxy compound and acid anhydride, and 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 diisocyanate is not particularly limited,
For example, the following types are listed. 2,4-tolylene diisocyanate, 2,4-tolylene diisocyanate and 2,
Examples include a mixture with 6-tolylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and the like. Among them, hexamethylene diisocyanate is preferable from the viewpoints of the hue of the produced resin, reactivity at the time of addition, 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 occurs.

The addition is preferably 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 device or to a molten polyester prepolymer (for example, in a kneader). Is practical.

In this case, the aliphatic polyester has a number average molecular weight of 10,000 or more, which makes the polyester resin and the polyester resin composition have sufficient mechanical properties.

The filler used in the present invention is generally widely used in the fields of synthetic resin and rubber.
As these fillers, inorganic compounds or metals that do not react with oxygen and water and those that do not decompose during kneading and molding are preferably used. As the filler, oxides of metals such as aluminum, copper, iron, lead, nickel, magnesium, calcium, barium, zinc, zirconium, molybdenum, silicon, antimony and titanium,
Compounds such as hydrates (hydroxides), sulfates, carbonates, and silicates, double salts thereof, mixtures thereof, carbon fibers, and the like can be given. A typical example of the filler is Japanese Patent Application No.
9-124481.

Of these fillers, the powdery ones preferably have a diameter of 30 μm or less (more preferably 10 μm or less). In the case of fibrous materials, the diameter is 1-100μ
m (preferably 1 to 80 μm) and a length of 0.1 to 1
A diameter of 0 mm (preferably 0.1 to 5.0 mm) is desirable. Further, the flat plate preferably has a major axis of 30 μm or less (preferably 10 μm or less). Among these fillers, flat plate-shaped (flake-shaped) and powdered ones are particularly preferable.

The composition ratio (content ratio) of the inorganic filler in the polyester resin composition is 10 to 70% by weight, preferably 15 to 65% by weight, and more preferably 20 to 60% by weight.
Weight percent is preferred. When the composition ratio of the inorganic filler in the polyester resin composition containing an inorganic filler exceeds 70% by weight, the impact resistance of the obtained injection-molded article is significantly lowered, and only a molded article suitable for practical use can be obtained. On the other hand, 10
If it is less than wt%, the combustion calorific value is 5,000 kcal / k.
It does not fall below g, and no improvement in rigidity or heat resistance is observed.

The aliphatic polyester resin composition thus obtained has a temperature of 190 ° C. and a shear rate of 1,000 (s).
The melt viscosity in ec ⁻¹ ) is 1 × 10 ³ to 1 × 10 ⁵ poise. The porosity is preferably 2 × 10 ³ to 8 × 10 ³ poises, particularly preferably 2 × 10 ^{3 to} 6 × 10 ³ poises. If it is less than 1 × 10 ³ poise, the strength of the injection-molded product will be insufficient and the injection molding will be unstable. On the other hand, if it exceeds 1 × 10 ⁵ poise, injection molding becomes difficult, and the molded product is easily deformed due to residual distortion.

The melt viscosity was measured with a nozzle diameter of 1.0.
mm, and using a capillary rheometer with a nozzle of L / D = 10, the shear rate measured at a resin temperature of 190.degree.
The viscosity at c ^-1 was determined.

The purpose of producing the polyester resin composition of the present invention can be achieved by uniformly mixing the polyester resin and the filler in a desired ratio.
As a mixing method, there is a method of kneading in a molten state using a mixer such as an extruder, a mixing roll, a kneader, a roll mill, a Banbury mixer, and a continuous mixer which are usually used in the field of olefin polymers. Alternatively, a masterbatch (mixture) obtained by producing a high-concentration filler masterbatch such as polyester resin
And polyester resin may be mixed.

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 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 urethane bond is small and the moldability is poor, and if it exceeds 3.0% by weight, gelation occurs.

The polyester resin composition thus obtained may be used as it is, but depending on the purpose of use, the antioxidants, heat stabilizers, and ultraviolet rays commonly used in the field of olefin polymers are used. The above-mentioned characteristics (effect) of the polyester resin composition of the present invention having additives such as a lubricant, a processability improving agent, a colorant, an antistatic agent, an electrical property improving agent or an adhesiveness improving agent in addition to the absorbent and the like. May be added as long as it does not impair.

The polyester resin composition according to the present invention is molded by an ordinary injection molding machine, and the molding temperature is generally 170 to 240 ° C, preferably 180 to 190 ° C. Formability is insufficient near the melting point, and if it exceeds 240 ° C, the molded product is likely to be deformed or thermally decomposed.

In the following examples, the flexural modulus was ASTM D790 and the tensile strength was JIS K-6758.
The heat generation amount of combustion was measured under the conditions of the pulling speed of 50 mm / min based on the calorimeter method of JIS M8814.

[0040]

【Example】

(Example 1) After purging a 700 L reactor with nitrogen,
1,4-butanediol 183 kg, succinic acid 224 k
I charged g. 195 the temperature is raised in a nitrogen stream.
~ 210 ° C for 3.0 hours, then stop nitrogen and 15 ~
The esterification reaction by dehydration condensation was performed for 3.5 hours under a reduced pressure of 5 mmHg. The sample collected had an acid value of 9.2 mg / g and a number average molecular weight (Mn) of 5,200.
The weight average molecular weight (Mw) was 10,100.
Subsequently, 34 g of tetraisopropoxytitanium as a catalyst was added under a nitrogen stream under normal pressure. The temperature is raised to 7.5-0.2 mmHg at a temperature of 215 to 220 ° C. and a reduced pressure of 7.5.
The deglycol reaction was performed for a period of time. 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) was 339 kg when condensed water was removed.

4070 g 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, 1700 g of Irganox 1010 (manufactured by Ciba Geigy) as an antioxidant and 1700 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. 90 ° C
The yield of the polyester (B1) after vacuum drying for 6 hours was 270 kg.

The obtained polyester (B1) is a slightly ivory white waxy crystal and has a melting point of 110.
C., the number average molecular weight (Mn) is 29,500, the weight average molecular weight (Mw) is 127,000, the MFR (190 ° C.) is 9.2 g / 10 minutes, and the viscosity of a 10% solution of orthochlorophenol is 170 poises. Temperature 190 ℃, shear rate 1,
The melt viscosity at 000 sec ⁻¹ was 3.0 × 10 ³ poise. The average molecular weight is measured by Shodex GP
C System-11, the solvent was 5 mmol solution of CF ₃ COONa in hexafluoroisopropyl alcohol, the concentration was 0.1% by weight, and the calibration curve was Showa Denko KK PMMA standard sample Shodex Standard M-7.
I went to 5.

Then, this polyester resin (B1) 70
After blending a mixture of wt% and 30 wt% of talc having an average particle size of 5.0 μm with a Henschel mixer, a resin temperature of 18 was obtained using a twin-screw extruder with a screw diameter of 50 m / m in the same direction.
The polyester resin composition (C
1) was obtained. This composition has a temperature of 190 ° C. and a shear rate of 1,
The melt viscosity at 000 sec ⁻¹ was 4.5 × 10 ³ poise.

<< Method and Conditions for Manufacturing Sheet Using Polyester Composition (C1) >> The polyester composition (C1) was molded at a molding temperature of 210 ° C. by an injection molding machine (IS- manufactured by Toshiba Machine Co., Ltd.).
80A) was used to produce injection molded bodies. The bending elastic modulus of the obtained injection-molded product was 7,600 kg / cm ² , the tensile strength was 580 kg / cm ² , and the calorific value of combustion was 4,200 kca.
It was 1 / kg. When this molded body was buried in soil for 5 months, it was decomposed into a state in which it was easily broken.

(Example 2) The filling amount of talc was 40% by weight.
The same procedure as in Example 1 was carried out except that The melt viscosity at a shear rate of 1,000 sec ⁻¹ is 5.3 × 10 ^3.
It was a poise and there was no problem in molding. The bending elastic modulus of the obtained molded body was 8,200 kg / cm ² , and the tensile strength was 60.
0 kg / cm ² , combustion calorific value 3,600 kcal / k
It was g. When this molded body was buried in soil for 5 months, it was decomposed into a state in which it was easily broken as in Example 1.

Example 3 The same procedure as in Example 1 was carried out except that the filler was calcium carbonate having an average particle size of 1 μm. The melt viscosity at a shear rate of 1,000 sec ⁻¹ was 3.9 × 10 ³ poise, and there was no problem in molding.
The flexural modulus of the obtained molded body is 7,000 kg / cm.
² , tensile strength 560 kg / cm ² , combustion calorific value 4.1
It was 50 kcal / kg. When this molded body was buried in soil for 5 months, the same results as in Example 1 were obtained.

(Example 4) A 700 L 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 2 mmHg. The sample collected had an acid value of 6.3 mg / g and a number average molecular weight (Mn) of 5,20.
0, and the weight average molecular weight (Mw) was 10,100. Subsequently, 34 g of tetraisopropoxytitanium as a catalyst was added under a nitrogen stream under 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 5.5 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 (A2) was 339 kg when condensed water was removed.

4.07 kg of hexamethylene diisocyanate was added to a reactor containing 339 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, 1.70 kg of Irganox 1010 (manufactured by Ciba Geigy) as an antioxidant 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. 90
The yield of polyester (B2) after vacuum drying at 6 ° C. for 6 hours was 270 kg.

The polyester (B2) obtained was a slightly ivory-like white wax-like crystal having a melting point of 110.
° C, number average molecular weight (Mn) is 29,500, weight average molecular weight (Mw) is 127,000, MFR (190 ° C) is 18 g / 10 minutes, viscosity of 10% solution of orthochlorophenol is 190 poise, temperature 190 ℃, shear rate 1,0
The melt viscosity at 00 sec ⁻¹ was 1.5 × 10 ³ poise.

Then, this polyester resin (B2) was blended with 70 wt% of this resin and 30 wt% of talc having an average particle size of 5 μm in the same manner as in Example 1 after blending with a Henschel mixer, and then biaxial twin screw with a screw diameter of 50 m / m. Using an extruder, the mixture was kneaded and pelletized at a resin temperature of 200 ° C. to obtain a polyester resin composition (C2). This composition has a temperature of 1
The melt viscosity at 90 ° C. and a shear rate of 1,000 sec ⁻¹ was 6.6 × 10 ³ poise.

Molding temperature of polyester (C2) 210 ° C.
Then, an injection molded body was manufactured using an injection molding machine (IS-80A) manufactured by Toshiba Machine Co., Ltd. The bending elastic modulus of the obtained injection-molded product was 6,100 kg / cm ² , and the tensile strength was 500 kg /.
cm ² , and the calorific value of combustion was 4,200 kcal / kg. When this molded body was buried in soil for 5 months, the shape of the molded body deteriorated and decomposed.

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. The calorific value of combustion was 4,140 kcal / kg.

[0053]

INDUSTRIAL APPLICABILITY The injection-molded article molded from the composition in which the aliphatic polyester resin of the present invention is mixed with a filler has biodegradability when buried in soil or the like, and generates combustion heat even if incinerated. The amount is about one-third as low as that of polyolefin resins such as polypropylene and polyethylene, it is about the same as paper, and it has excellent mechanical strength.
It is useful as a member for automobiles, food containers, beverage containers and the like.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location C08K 3/22 KJR 7242-4J // B29K 67:00 (72) Inventor Eiichiro Takiyama Kamakura City, Kanagawa Prefecture 4-12-4 Nishi-Kamakura

Claims (4)

[Claims] 1. A polyester resin composition comprising a filler and an aliphatic polyester having a number average molecular weight of at least 10,000 and a melting point of 70 ° C. or higher, which is synthesized from glycol and an aliphatic dicarboxylic acid or an acid derivative thereof. A polyester resin composition for injection molding, which has a melt viscosity of 1 × 10 ³ to 1 × 10 ⁵ poise at a temperature of 190 ° C. and a shear rate of 1,000 sec ⁻¹ . 2. A product obtained by reacting 0.1 to 5 parts by weight of 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. 1. The polyester resin composition according to 1. 3. A resin composition obtained by blending 10 to 70% by weight of a filler such as a metal oxide, a hydroxide, a sulfate or a silicate and having a combustion calorific value of 5,000 kcal /
below Ikg, Izod impact strength is 0.8kg · c
It is m / cm or more, The polyester resin composition of Claims 1-2. 4. An injection-molded article made of the polyester resin composition according to claim 1, which has a tensile strength of 250 kg / cm ² or more.