JPH11323104A - Highly biodegradable pipe, joint and molding process thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly biodegradable pipe or joint which forms a void for rainwater storage and infiltration into underground and therefore greatly improves the penetrability of rainwater into the ground, and a molding process thereof SOLUTION: A highly biodegradable pipe or joint comprises a polyalkyl alkanoate resin, wherein the melt flow rate(MFR) at 190 deg.C under a load of 2.16 kgf is within the range of from 0.5 to 30 g/10 min, and is obtained by melting and extrusion molding a polyalkyl alkanoate resin which comprises as structural units an aliphatic dicarboxylic acid component or a derivative component thereof and an aliphatic diol component and has a moisture content of 2.0% or lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe and a joint excellent in biodegradability (hereinafter, simply referred to as a pipe) and a method of forming the same.

[0002]

2. Description of the Related Art Urban areas are vulnerable to torrential rain, roads are flooded in a short time, and floods such as indoor flooding are likely to occur. For this reason, in some cities, as a countermeasure against floods, permeation systems using rainwater soil to bury perforated polyvinyl chloride resin pipes in residential lands and prepare for temporary flooding during torrential rain have been promoted. There is a limit on the hole area, the penetration of rainwater into the soil is insufficient, and the control of the amount of rainwater flowing out of the residential land is not sufficient.

[0003]

SUMMARY OF THE INVENTION The present invention relates to a rainwater storage and storage system.
It is an object of the present invention to provide a pipe having excellent biodegradability that greatly improves rainwater permeability into soil by forming voids for infiltration in the ground, and a method for molding the pipe.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, polyalkylalkanoate-based resins have excellent biodegradability in soil. It has been found that the object can be achieved by burying it in the soil, and the present invention has been completed based on this finding.

That is, the pipe of the present invention has a temperature of 190.
A polyalkylalkanoate resin having a melt flow rate (hereinafter abbreviated as MFR) under a load of 2.16 kgf in the range of 0.5 to 30 g / 10 min.
Excellent biodegradability. Further, the pipe having excellent biodegradability of the present invention can be obtained by melting and extruding the polyalkylalkanoate resin having a water content of 2.0% or less. In particular, when the water content is suppressed to 2.0% or less, hydrolysis of the ester bond of the resin is suppressed, and molding can be performed while sufficiently maintaining the strength of the molded product.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The polyalkylalkanoate-based resin usable in the present invention is a biodegradable resin containing an aliphatic dicarboxylic acid component or a derivative thereof and an aliphatic diol component as constituent units.

The aliphatic dicarboxylic acids include, for example, succinic acid, adipic acid, suberic acid, sebacic acid,
Dodecane diacid and their anhydrides, derivatives and the like,
At least one is selected from these. Examples of the aliphatic diol include ethylene glycol, propylene glycol, butylene glycol, 1,4-butanediol, 1,6-hexanediol, decamethylene glycol, neopentyl glycol, cyclohexamethylene glycol, and derivatives thereof. And at least one of them is appropriately selected. All are compounds having an alkylene group, cyclocyclic group or cycloalkylene group having 2 to 20 carbon atoms, and the polyalkylalkanoate resin of the present invention is produced by condensation polymerization of these compounds.

Further, in order to improve the tension of the melt, a trifunctional or higher polyhydric alcohol such as glycerin, trimethylolpropane or pentaerythritol, or a trifunctional or higher functional oxycarboxylic acid such as citric acid or tartaric acid (or anhydride thereof) is used. ) And a tri- or higher-functional polycarboxylic acid (or an anhydride thereof) such as trimetic anhydride may be used to form a long-chain branch in the molecular chain. Further, a small amount of a diisocyanate compound such as hexamethylene diisocyanate, isophorone diisocyanate, or xylylene diisocyanate may be used as a chain extender.

The polyalkylalkanoate resin used in the present invention has an MFR at a temperature of 190 ° C. under a load of 2.16 kgf in a range of 0.5 to 30 g / 10 minutes. It is preferably in the range of 0.5 to 25 g / 10 minutes, and more preferably in the range of 0.5 to 20 g / 10 minutes. If the MFR exceeds 30 g / 10 minutes, melt extrusion molding is difficult, and the strength of the pipe is low, which is not preferable for practical use. In addition, those having an MFR of less than 0.5 g / 10 min are not usually commercially available and must be specially manufactured, which is undesirably high in cost.

When a pipe is formed from a polyalkylalkanoate-based resin, the resin has a water content of 2.0% or less. Preferably it is 1.5% or less, more preferably 1.0% or less. When the water content of the polyalkyl alkanoate resin exceeds 2.0%, the ester bond in the polyalkyl alkanoate resin undergoes a hydrolysis reaction during melt extrusion molding to decompose, and the toughness of the formed pipe is increased. Is not preferred in practice.

A lubricant, an antioxidant, a filler, and a polyhydroxyalkanoate resin may be added to the pipe made of the polyalkylalkanoate resin of the present invention, if necessary, so as not to impair desired physical properties. Can be.

Examples of the lubricant include fatty acids such as lauric acid, myristic acid, stearic acid, oleic acid and behenic acid, and metal salts of fatty acids having 12 to 30 carbon atoms such as lead stearate, zinc stearate, calcium stearate and calcium hydroxystearate. , Zinc stearate / barium stearate complex, zinc stearate / lead stearate / calcium stearate complex,
Aliphatic amides such as oleic acid amide, stearic acid amide, erucic acid amide, lauric acid amide, palmitic acid amide, behenic acid amide, ricinoleic acid amide, pentaerythritol mono / diester, pentaerythritol tetrastearate, dipentaerythritol hexastea Rate, pentaerythritol-adipic acid-
Stearate / complex ester (trade name: RIQUESTER EW)
-200, RIQUESTER EW-250, manufactured by Akishima Chemical Industry Co., Ltd., dipentaerythritol-adipic acid-stearic acid complex ester (trade name: RIQUESTER EW-10)
0, manufactured by Akishima Chemical Industry Co., Ltd.), an alkyl-modified silicone having a viscosity at 25 ° C. in the range of 10 to 10,000 cSt, a methylstyryl-modified silicone,
Polyether-modified silicone, higher fatty acid alkoxy-modified silicone, higher fatty acid-containing silicone, higher fatty acid ester-modified silicone, methacryl-modified silicone,
Modified silicone such as fluorine-modified silicone, dimethyl silicone or methyl phenyl silicone having a viscosity at 25 ° C. in the range of 10 to 10,000 cSt, paraffin and the like can be mentioned. Among them, fatty acids, modified silicones and composite esters are preferred.

The amount of the lubricant to be added is 5.0 parts by weight or less, preferably 3.0 parts by weight or less based on 100 parts by weight of the polyalkylalkanoate resin. If the amount exceeds 5.0 parts by weight, a bleeding phenomenon in which the additive floats out occurs, which adversely affects the appearance and mechanical properties.

As antioxidants, 2,6-di-tert-butyl-p-cresol, 2,2'-methylenebis (4-
Methyl-6-t-butylphenol), 4.4′-butylidenebis (3-methyl-6-t-butylphenol), pentaerythrityl-tetrakis [3- (3,5
-Di-t-butyl-4-hydroxyphenyl) propionate], bis [3,3'-bis- (4'-hydroxy-3'-t-butylphenyl) butyric acid] glycol ester, 3,9-bis [2- [3- (3-t
-Butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1-dimethylethyl] -2,4.
Phenols such as 8,10-tetraoxaspiro [5,5] undecane, and 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, diphenylisodecyl phosphite, tris (2,4- Di-t-butylphenyl) phosphite, cyclic neopentanetetraylbis (2,6-di-t-butyl-
Phosphorus such as 4-methylphenyl) phosphite.

The addition amount of the antioxidant is 20 parts by weight or less, preferably 1.0 part by weight or less based on 100 parts by weight of the polyalkylalkanoate resin. Even if it is added in excess of 20 parts by weight, no further effect of the antioxidant is recognized.

Further, a filler may be added, and the filler may be either an inorganic filler or an organic filler. Examples of the inorganic filler include, for example, at least one metal oxide selected from metals such as magnesium, calcium, barium, boron, aluminum, silicon, titanium, zirconium, and hafnium, as well as hydroxides and carbonates of these metals. Salts, sulfates or silicates can be mentioned. Among them, it is preferable to use calcium carbonate. The calcium carbonate may be either heavy calcium carbonate or light calcium carbonate.

On the other hand, examples of the organic filler include cereals such as wheat, corn, and rice; potato starch such as potato, sweet potato, and tapioca; and polysaccharides such as cellulose, chitin, and chitosan. These may be used alone or in combination of two or more. The above-mentioned inorganic filler is a silane coupling agent for the purpose of improving aggregation between particles and affinity with the polyalkylalkanoate-based resin,
The surface may be modified by a dry method, a wet method, or an integral blend method using a titanate coupling agent, an aluminate coupling agent, a surface modifier such as acetylene glycol or acetylene alcohol.

The amount of these fillers is not more than 80 parts by weight based on 100 parts by weight of the polyalkylalkanoate resin. Preferably it is 50 parts by weight or less. If it exceeds 80 parts by weight, the obtained pipe loses toughness, which is not preferable.

The average particle size of the inorganic filler used in the present invention is in the range of 0.01 to 10 μm. More preferably, it is in the range of 0.05 to 5 μm. If it is less than 0.01 μm, the state of dispersion of the filler in the resin is poor, and if it exceeds 10 μm, the strength of the pipe may be reduced.

Examples of the polyhydroxyalkanoate resin include a copolymer of 3-hydroxybutyric acid and 3-hydroxyvaleric acid, polylactic acid and poly (ε-caprolactone).

Further, the pipe having excellent biodegradability according to the present invention may contain, if necessary, a surfactant such as glycerin fatty acid ester, polyglycerin fatty acid ester, di-2-ethylhexyl azelate, sodium lactate, calcium lactate, etc. Lactic acid inorganic salts such as magnesium lactate and aluminum lactate, pigments, and other additives can be appropriately added. Further, the pipe can be formed by known extrusion molding. At this time, if the water content of the polyalkylalkanoate-based resin is 2.0% or less, a pipe having sufficient strength can be obtained.

[0022]

EXAMPLES Hereinafter, specific embodiments of the present invention will be described based on examples and comparative examples, but the present invention is not limited to these examples. The performance of the pipe was evaluated according to the following method. (1) JIS under conditions of MFR temperature 190 ° C and load 2.16kgf
It was measured according to K7210. (2) Moisture Content of Resin The resin was measured at a temperature of 200 ° C. and a N ₂ drive-out method using a gravimetric titration type moisture measuring device: Mitsubishi CA-06 (Mitsubishi Chemical Corporation, product name). (3) Biodegradability of pipe A 10 cm × 10 cm square specimen cut out from a pipe is buried in a 30 cm deep soil outdoors in Omiya City, Saitama Prefecture,
After leaving it for 6 months from April to September, it was taken out, washed with water and dried, and its biodegradation rate (%) was evaluated by the following formula.

The following polyalkylalkanoate resins were used. Bionore 1001 (trade name: polybutylene succinate, manufactured by Showa Kogyo) Bionore 3001 (trade name: polybutylene succinate adipate, manufactured by Showa Polymer) Bionore 1010 (trade name: polybutylene succinate, Showa Polymer) Bionole 1020 (trade name: polybutylene succinate, manufactured by Showa Kogyo Co.) Bionole 1030 (trade name: polybutylene succinate, manufactured by Showa Polymer Co.) Bionole 1903 (trade name having a long-chain branched structure: poly) Alkyl alkanoate resin, manufactured by Showa Polymer Co., Ltd.)

(Example 1) MFR was 1.0 g / 10 minutes,
75 m of Bionole 1001 with a moisture content of 0.16%
m twin screw extruder, cylinder temperature 190 ° C ~ 21
After melt-kneading at 0 ° C, the mixture was discharged from a mold heated to 210 ° C to produce a pipe having an outer diameter of 114 mm and a wall thickness of 3.1 mm. The resulting pipe had sufficient strength for use. Biodegradability was 63%.

(Example 2) MFR is 2.3 g / 10 minutes,
Bionole 3001 with a moisture content of 0.3% is 75 mm
Feed to twin screw extruder, cylinder temperature 180 ° C ~ 200
After melting and kneading at 200C, the mixture was discharged from a mold heated to 200C to produce a pipe having an outer diameter of 114 mm and a wall thickness of 3.1 mm. The resulting pipe had sufficient strength for use.
Biodegradability was 75%.

Example 3 MFR is 10.3 g / 10
Bionole 1010 (A) with a water content of 1.3%
And a bionore 1903 (B) having an MFR of 3.4 g / 10 min and a water content of 0.35% were obtained by weight composition ratio (A) /
The composition blended so that (B) = 85/15 (A + B = 100) is supplied to a 75 mm twin-screw extruder and melt-kneaded at a cylinder temperature of 150 ° C. to 170 ° C.
It was discharged from a mold heated to 0 ° C. to produce a pipe having an outer diameter of 114 mm and a wall thickness of 3.1 mm. The resulting pipe had sufficient strength for use. Biodegradability was 68%.

Example 4 MFR was 1.0 g / 10 min,
Calcium bicarbonate (trade name: Whiten SB, manufactured by Shiraishi Calcium Co.) having an average particle size of 1.84 μm based on 1001100 parts by weight of bionole having a water content of 0.16%.
20 parts by weight, behenic acid (trade name: ADK STAB EXL)
-5, manufactured by Asahi Denka Kogyo Co., Ltd.) 0.4 parts by weight, pentaerythritol adipate stearate / complex ester (trade name: RIQUESTER EW-200, manufactured by Akishima Chemical Industry Co., Ltd.)
The composition consisting of 4 parts by weight was melt-kneaded in a pressure kneader heated to 130 ° C. for 20 minutes, and immediately melt-kneaded in a mixing roll heated to 130 ° C. for 5 minutes to produce a sheet-like molded product. After cooling this sheet-shaped molded product to 70 ° C. or less at room temperature, it was pulverized with a pelletizer to form a pellet. The pellet was dried at 80 ° C. overnight. The moisture content of the pellets was 0.35%. Also, MF
R was 0.7 g / 10 minutes. 75 of these pellets
mm twin screw extruder, cylinder temperature 190 ° C ~ 2
After melt-kneading at 10 ° C., the mixture was discharged from a mold heated to 210 ° C. to produce a pipe having an outer diameter of 114 mm and a wall thickness of 3.1 mm. The resulting pipe had sufficient strength for use. Biodegradability was 83%.

(Example 5) MFR is 20.5 g / 10
Using a Bionole 1020 having a water content of 0.50%, a 90-degree elbow type inner diameter 107 mm joint was formed by an injection molding machine having a mold clamping force of 300 t. The injection conditions were as follows: barrel temperature: 175 ° C., nozzle temperature: 165 to 175 ° C., injection speed: 60%, injection pressure: 500 kg / cm ² . The obtained joint had sufficient strength and could withstand practical use. Biodegradability was 65%.

(Example 6) Using the pipe obtained in Example 1 and the joint obtained in Example 5, a facility for rainwater infiltration was constructed 70 cm in the soil. 1 from April to March of the following year
It was used as a rainwater infiltration facility for two months. After 12 months, when I dug a rainwater infiltration facility,
Both joints did not retain their original shape, and the existence of voids corresponding to these was confirmed in the buried place.

(Comparative Example 1) MFR is 23.4 g / 10
Of bionole 1020 having a water content of 0.15%
Feed to 5mm twin screw extruder, cylinder temperature 160 ~ 1
After melt-kneading at 70 ° C, the mixture was discharged from a mold heated to 107 ° C. As a result, the melt-kneaded material discharged from the mold had a remarkable drawdown, could not maintain its shape, and could not form a pipe.

(Comparative Example 2) Bionole 1001 having an MFR of 1.0 g / 10 min and a water content of 0.16% used in Example 1 was left in a thermo-hygrostat at 60 ° C. and 95% RH for 10 days. The obtained resin having a water content of 2.3% was molded using the same extruder as in Example 1 under the same conditions. The resulting pipe did not have the strength to withstand use.

[0032]

As described above, the pipe of the present invention is biodegraded in the soil as described above, and a void having an inner surface of the ground is formed at the mark, thereby facilitating the penetration of rainwater into the ground. For this reason, both the permeability of rainwater on the ground surface and the rate of penetration into the ground were significantly improved.

Claims (2)

[Claims] An excellent biodegradability characterized by comprising a polyalkylalkanoate resin having a melt flow rate at a temperature of 190 ° C. and a load of 2.16 kgf in a range of 0.5 to 30 g / 10 minutes. Pipes and fittings. 2. A polyalkylalkanoate resin having an aliphatic dicarboxylic acid component or a derivative component thereof and an aliphatic diol component as constituent units and having a water content of 2.0% or less is melted and extruded. A method for forming pipes and joints with excellent biodegradability.