JPH09227672A - Aliphatic ester-amide copolymer resin and resin solution - Google Patents

Abstract

(57) Abstract: [PROBLEMS] To provide a resin and a resin solution that can be dissolved in an organic solvent that is degradable or disintegratable by microorganisms, has low toxicity, and is highly safe for the human body. SOLUTION: The weight average molecular weight is 1,000 to 10,0.
An aliphatic ester-amide copolymer resin and a solution thereof which are soluble in an organic solvent having a low toxicity and a high safety to human body. [Effect] In addition to having degradability or disintegration by microorganisms,
It is soluble in organic solvents that have low environmental impact, low toxicity, and high safety to the human body. Therefore, it is possible to easily perform molding by a method such as a casting method using a resin solution in which the resin is dissolved in an organic solvent without applying excessive heat or shear to the resin, so that deterioration of the resin during processing or There is no problem due to disassembly.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an aliphatic ester
It relates to an amide copolymer resin and a resin solution. More specifically, the present invention has degradability or disintegration by microorganisms,
The present invention relates to an aliphatic ester-amide copolymer resin and a resin solution having a specific weight average molecular weight that can be dissolved in an organic solvent that has low toxicity and is highly safe for the human body.

[0002]

2. Description of the Related Art Biodegradable plastics represented by aliphatic polyester resins have been attracting much attention due to the recent growing interest in environmental issues, and are expected to be used in various applications. ing. However, aliphatic polyester resins do not have good solvents that are easy to handle,
It is extremely difficult to perform molding by a method generally used for general-purpose resins, for example, a solvent casting method in which a resin is in a solution state. For example, formic acid, hexafluoro-2-propanol, m-cresol and the like are known as solvents. However, since these are extremely harmful to the human body and have high environmental destructiveness such as ozone layer depletion, they are very difficult to handle and cannot be used unless expensive equipment is provided. Thus, the aliphatic polyester resin is difficult to mold from a solution state,
There is a drawback that its range of use is extremely limited.

The aliphatic ester-amide copolymer resin has both the toughness of the aliphatic amide resin and the good processability of the aliphatic ester resin, and further has the biodegradability of the aliphatic polyester resin. (JP-B-56-38115, JP-B-57-26688, and JP-A-6-200016).
Japanese Patent Laid-Open No. 6-192417, etc.).

[0004]

However, similar to the aliphatic polyester resin, the aliphatic ester-amide copolymer resin is also used as a solvent in a solution state, formic acid, hexafluoro-2-propanol, which is harmful to the human body and the environment, Only m-cresol and the like are known, and there is no good solvent that is easy to handle and has little harm to the human body and environment in molding. Therefore, at present, the use range of the aliphatic ester-amide copolymer resin is also extremely limited.

In view of the above-mentioned problems, the inventor of the present invention can form a resin component into a desired shape by a simple operation without using a solvent having strong toxicity or environmental pollution, and further can be decomposed or disintegrated by microorganisms. As a result of diligent studies on ester-amide copolymer resin and resin solution having properties, the present invention has been accomplished.

[0006]

The present invention is thus characterized by having a weight average molecular weight in the range of 1,000 to 10,000 and being soluble in an organic solvent having low toxicity and high safety to humans. An aliphatic ester-amide copolymer resin is provided. Further, there is provided an aliphatic ester-amide copolymer resin solution, characterized in that the aliphatic ester-amide copolymer resin is dissolved in an organic solvent having low toxicity and high safety to human body.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The copolymer resin of the present invention has a weight average molecular weight in the specific range of 1,000 to 10,000. When the weight average molecular weight is less than 1,000, the properties as a resin, particularly the strength becomes too weak to maintain its shape, which is not preferable. Further, if the weight average molecular weight is more than 10,000, it is not preferable since it is not possible to impart solubility to an organic solvent having low toxicity and high safety for human body. The weight average molecular weight is 4,000 to 9,000.
Is preferred, specifically 4,000, 4,500, 5,
000, 5,500, 6,000, 7,000, 8,000
00, 9,000.

The aliphatic ester-amide copolymer resin of the present invention comprises ester units and amide units. The copolymer resin of the present invention has an amide unit ratio of 10 to 8 in all units.
A content of 0 mol% is preferable because better biodegradability is imparted. Here, if the proportion of amide units exceeds 80 mol%, degradability or disintegration by microorganisms is lost, which is not preferable. Here, the term "disintegrability" means that the shape of the resin is disintegrated by microorganisms, and the resin pieces mainly containing amide units are stable against microorganisms. In order for the microorganism to be completely decomposed to the molecular level (hereinafter referred to as completely biodegradable), the upper limit of the ratio of the amide units is preferably 70 mol%, more preferably 60 mol%. The lower limit of the ratio of amide units is 10 mol%. When the proportion of the amide unit is less than 10 mol%, the amount of the amide group contained in the copolymer resin is too low, and the solubility in an organic solvent is lost, which is not preferable. Generally, a compound that is a raw material for an ester unit is more expensive than a compound that is a raw material for an amide unit, and therefore a completely biodegradable resin is more expensive. Make the copolymer resin disintegrable,
Whether to be completely biodegradable may be determined according to the performance required by the application and the cost.

The ester unit contains an aromatic ring.
Any ester unit can be used as long as it is not
For example, the following formula (1) or formula (2) -OR₁-CO- (1) (In the formula, R₁Is a linear alkylene group having 1 to 6 carbon atoms or
Is a part of hydrogen atoms of the straight chain alkylene group has 1 carbon atom.
A branched alkylene group substituted with an alkyl group of
Show. ) -OR_Two-OCO-R_Three-CO- (2) (In the formula, R_TwoIs a linear alkylene group having 2 to 6 carbon atoms or
Some of the hydrogen atoms of the straight-chain alkylene group have 1 to 3 carbon atoms.
A branched alkylene group substituted with an alkyl group, R _ThreeIs charcoal
Linear alkylene group having a prime number of 2 to 10 or the linear alkylene group
Part of the hydrogen atoms of is substituted with an alkyl group having 1 to 3 carbon atoms.
Is a branched alkylene group. ) Consisting of
Units are preferred. Formula (1) and formula (2) can be used alone or in combination.
You may let me.

Specific examples of R _{1 in} the above general formula (1) include --CH _2- , --CH (CH ₃ )-, --CH (C
_{H 3) CH 2 -, -} CH (C 2 H 5) CH 2 -, - CH
_{(CH 3) (CH 2)} 3 -, - (CH 2) 5 - , and the like. Specific examples of R _{2 in} the above general formula (2) include:
_{(CH 2) 2 -, CH} (CH 3) CH 2 -, - (C
H ₂ ) ₄ −, — (CH ₂ ) ₆ − and the like can be mentioned. Specific examples of R _{3 in} the above general formula (2) include — (CH ₂ )
_{2 -, CH (CH 3)} CH 2 -, - (CH 2) 4 -, -
_{(CH 2) 6 -, -} (CH 2) 8 - , and the like.

Any amide unit may be used as long as it does not contain an aromatic ring. For example, the following formula (3) or formula (4) --NH--R ₄ --CO-- (3) In the formula, R ₄ represents a linear alkylene group having 2 to 12 carbon atoms or a branched alkylene group in which a part of hydrogen atoms of the linear alkylene group is substituted with an alkyl group having 1 to 3 carbon atoms.) —NH—R ₅ —NHCO—R ₆ —CO— (4) (In the formula, R ₅ is a linear alkylene group having 2 to 6 carbon atoms, or a part of hydrogen atoms of the linear alkylene is carbon. A branched alkylene group substituted with an alkyl group having 1 to 3 atoms, R ₆ is a linear alkylene group having 2 to 10 carbon atoms, or a part of hydrogen atoms of the linear alkylene is 1 carbon atom. A branched alkylene group substituted with an alkyl group of 3 to 3). Units are preferred. The formulas (3) and (4) may be used alone or in combination.

R in the general formula (3)_FourAs a specific example of
Is-(CH_Two)_Three-,-(CH_Two) _Five-,-(C
H_Two)₁₁-And the like. Further, in the above general formula (4)
R_FiveAnd R₆Specific examples of_Twoas well as
R_ThreeThe groups exemplified in 1. can be mentioned. Furthermore, the aliphatic of the present invention
Ester-amide copolymer resin with low toxicity to human body
Resin solution by dissolving in highly safe organic solvent
Can be obtained. Here, the dissolution in the present invention and
Is at room temperature or within the boiling point of the organic solvent used.
1 part by weight to 100 parts by weight of solvent under heating
It means that the resin of becomes a uniform solution. In the present invention,
For dissolution, after dissolving, separate organic solvent and copolymer resin
Of the resin and the organic solvent without substantially causing the precipitation of
Substantially uniform state, some resin gelled or
Is in a state where some separation of organic solvent occurs (especially at room temperature)
Shall be included. The resin solution contains 100 parts by weight of a solvent.
In contrast, the aliphatic ester-amide copolymer resin is 1 to 70
Parts by weight, preferably 1 to 50 parts by weight, specifically quintuple
Quantity part, 10 parts by weight, 20 parts by weight, 30 parts by weight, 40 parts by weight
It may be partially dissolved. Where the amount of resin is relatively high
The resin solution is useful as an adhesive.

Further, the amount of the aliphatic ester-amide copolymer resin is preferably 1 to 40 parts by weight, more preferably 1 to 30 parts by weight, based on 100 parts by weight of the organic solvent. Is preferred. If the amount of the copolymer resin is too small, the reprecipitation amount of the copolymer resin is small. If the amount is too large, precipitation of the copolymer resin is apt to occur, and it is difficult to form a uniform solution.

[0014] In the present invention a high safety organic solvents on the human body with low toxicity, LD ₅₀ value (rat oral administration) is meant 2,000 (mg / Kg) or more organic solvents.
In particular, an aliphatic organic solvent is preferable, and more specifically, an aliphatic alcohol having 6 or less carbon atoms, the following chemical formula (A) R ₇ (OCH ₂ CH ₂ ) _n R ₈ (A) (wherein R ₇ Is an alkyl group having 1 to 4 carbon atoms, R ₈ is a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, an amino group or an acetyl group, and n represents an integer of 1 to 3), an aliphatic glycol ether represented by Number 2-6 fatty acid, carbon number 2
6 aliphatic sulfoxide and a C2-C6 aliphatic amide are mentioned.

R ₇ is --CH ₃ , --CH ₂ C.
H _{3 and the} like. Further, as R ₈ , -OH,-
_{OCH 3, -OCH 2 CH 3,} -NH 2, -OCOCH
_{3 and the} like. Specific examples of the above aliphatic alcohols include methanol, ethanol, propanol, butanol, ethylene glycol and hexanediol. Specific examples of the aliphatic glycol ethers include 2-ethoxyethanol, 2-methoxyethanol, 2-ethoxyethyl acetate, 2-methoxyethylamine and the like. Examples of the aliphatic sulfoxide include dimethyl sulfoxide. Examples of the aliphatic amide include dimethylformamide and N-methyl-2-
And pyrrolidone.

These aliphatic organic solvents can be used alone or in admixture. The boiling point of the aliphatic organic solvent is preferably in the range of 30 to 250 ° C. in consideration of handleability at room temperature and easiness of removing and drying the solvent. A preferred organic solvent is an alcohol having 1 to 6 carbon atoms,
In particular methanol, ethanol, 2-ethoxyethanol, 2-methoxyethanol and mixtures thereof.

The aliphatic ester-amide copolymer resin contains both an ester unit and an amide unit in one polymer main chain, and has a property that the molecules are firmly bound by the binding force acting between the two units. Have. Further, when the bond between the ester units is strong, the bond of the ester unit portion of the polymer main chain is hard to separate at room temperature, so that when the resin is mixed with a solvent such as a lower alcohol, the resin may not be dissolved or may become a gel. is there. In this case, the bond between the ester units is more easily separated from the bond between the amide units by heating. Therefore, if the copolymer resin does not dissolve in the solvent, heating may be performed.

The organic solvent may or may not contain water. Whether or not water is contained, or the content of water, may be appropriately selected depending on the usage form, coating thickness, and the like of the resin. However, in order to obtain a solution having a high resin content, it is preferable that the water content is low.

Furthermore, by adding a small amount of an inorganic metal salt to the above organic solvent, the dissolution or dispersion of the resin can be promoted, and a solution having a high resin content can be easily obtained. As the inorganic metal salt, halides, nitrates and thiocyanates of metals selected from the groups Ia, IIa, Ib and IIb having an atomic number of 38 or less are preferable. These may be used alone or in appropriate combination. Preferred metals include lithium chloride, calcium chloride, magnesium chloride, zinc chloride, potassium chloride, lithium bromide, calcium bromide, magnesium bromide, zinc bromide, calcium nitrate, magnesium nitrate, zinc nitrate or lithium thiocyanide. Can be mentioned.

The resin solution of the present invention contains an aliphatic ester-amide copolymer resin, an organic solvent and water, as well as a surface active agent commonly used for improving the stability of the solution and improving the reprecipitated resin. Agents, antioxidants, plasticizers, etc., and dyes, pigments, etc. for coloring the reprecipitated resin may be contained. Further, when the aliphatic ester-amide copolymer resin is dissolved in an organic solvent, it is preferable to heat it. By heating in this way, the aliphatic ester-amide copolymer resin can be dissolved in a short time.
The heating temperature range is particularly preferably within the range not exceeding the boiling point of the organic solvent. This is because heating can be performed without using a pressure vessel or the like. The temperature when using a pressure vessel is preferably within the range of not higher than 200 ° C. This is because if the temperature is too high, the resin may decompose or gel.

In order to reprecipitate the copolymer resin from the resin solution, the organic solvent may be removed from the solution. In particular,
After applying the resin solution to the substrate, immersing the substrate in the resin solution, or pouring the resin solution into a mold, a resin having a specific shape can be precipitated by a simple method such as drying and washing with water.
In the resin solution of the present invention, since it is possible to use an organic solvent having a low effect on the environment and a low toxicity and a high safety for the human body, it is used for application and coating of a biodegradable resin, which has been conventionally difficult. Is possible.

[0022]

The present invention will be described in more detail below with reference to examples, but these examples do not limit the scope of the present invention. In all Examples and Comparative Examples, the weight-average molecular weight was measured by a Tosoh GPC device (model H
LC-8020) and Tosoh GPC column (Part No.
TSKgel GMHHR-M) was attached to the column at a temperature of 40 ° C., and 10 mMol was added to Central Glass Hexafluoroisopropanol (HFIP) as an eluent.
A solution of trifluoroacetic acid at a concentration of 1 / l was added to 0.
It was measured at a pressure of 50 kg / cm ² using a flow rate of 5 ml / min. As a standard sample, a standard sample for GPC of polymethyl methacrylate manufactured by Showa Denko KK was used. The ratio of amide units in the polymer is F, manufactured by Nicolet.
It measured using the T-IR apparatus.

Example 1 16.9 g of ε-caprolactam was placed in a glass separable flask and heated at 130 ° C. for 90 minutes to dry, then 70 mg of sodium was added and the temperature was raised to 170 ° C.
Subsequently, 17.1 g of ε-caprolactone was added over 20 minutes, and the reaction was carried out for 60 minutes while continuing stirring. 180 ° C
Then, unreacted components were removed under reduced pressure of 10 mmHg or less for 60 minutes to obtain an aliphatic ester-amide copolymer resin having a weight average molecular weight of 8,900 and an amide unit ratio of 50 mol%.

5 parts by weight of this copolymer resin was added to 100 parts by weight of methanol, and the mixture was stirred for 6 hours while keeping the temperature at 30 ° C. to obtain a resin mixture in a semitransparent solution in which the resin components were uniformly dispersed. The mixture was heated to 60 ° C. and became a clear resin solution. When a small piece of a thin copper plate was dipped in the mixture and dried, a translucent resin film was obtained on the surface. The copper piece on which the film was formed was left as it was for one week, but no abnormality such as corrosion was observed on the copper surface.

Similarly, a glass plate having a resin film formed on its surface was sampled from the factory premises in Tenri City, Nara Prefecture.
It is buried at a depth of 10 mm from the surface in a petri dish filled with soil that has been sieved with a 7 mm sieve, and the water content of the soil is 50%.
It was left in an incubator at 30 ° C. After one month, a considerable part of the film had disappeared, and black filamentous fungi were found to be attached to the remaining surface. When the surface was observed with a scanning electron microscope, it was found that the resin around the mycelium of the filamentous fungi had disappeared.

Example 2 16.9 g of ε-caprolactam was placed in a glass separable flask and heated at 130 ° C. for 90 minutes to dry, then 140 mg of sodium was added and the temperature was raised to 170 ° C. Subsequently, 17.1 g of ε-caprolactone was added all at once and reacted for 60 minutes while continuing stirring. Unreacted components were removed under reduced pressure of 10 mmHg or less at 180 ° C. for 60 minutes to obtain an aliphatic ester-amide copolymer resin having a weight average molecular weight of 4,500 and an amide unit ratio of 45 mol%.

5 parts by weight of this copolymer resin was added to 100 parts by weight of methanol, and the mixture was stirred for 6 hours while maintaining the temperature at 30 ° C. to obtain a resin mixture in a transparent solution in which the resin components were uniformly dispersed. The mixture was heated to 60 ° C. and became a clear resin solution. When a small piece of a thin copper plate was dipped in the mixture and then dried, a substantially transparent resin film was obtained on the surface. The copper piece on which the film was formed was left as it was for one week, but no abnormality such as corrosion was observed on the copper surface.

Similarly, a glass plate having a resin film formed on its surface was sampled from the factory premises in Tenri City, Nara Prefecture.
It was embedded at a depth of 10 mm from the surface in a petri dish filled with soil that had been sieved with a 7 mm sieve, and left in an incubator at 30 ° C. while maintaining the soil water content at 50%.
After 1 month, most of the film had disappeared, and black filamentous fungi were found to be attached to the remaining surface. When the surface was observed with a scanning electron microscope, it was found that the resin around the mycelium of the filamentous fungi had disappeared.

Comparative Example 1 16.9 g of ε-caprolactam was placed in a glass separable flask and heated at 130 ° C. for 90 minutes to dry, then 41 mg of sodium was added and the temperature was raised to 170 ° C.
Subsequently, 17.1 g of ε-caprolactone was added over 5 minutes and the reaction was continued for 60 minutes while continuing stirring. Unreacted components were removed under reduced pressure of 10 mmHg or less at 190 ° C. for 60 minutes to obtain an aliphatic ester-amide copolymer having a weight average molecular weight of 15,900 and an amide unit ratio of 45 mol%.

When 1 part by weight of this copolymer was added to 100 parts by weight of methanol and stirred for 6 hours while maintaining the temperature at 30 ° C., a part of the resin component was dispersed in the liquid to give a milky white dispersion liquid. Remained undissolved, and when left standing, a precipitate was formed. Even when the mixture was heated to 60 ° C., precipitation was generated in a stationary state and a uniform resin solution was not obtained.

[0031]

INDUSTRIAL APPLICABILITY The aliphatic ester-amide copolymer resin of the present invention is soluble in an organic solvent that has a low environmental impact, low toxicity, and high safety to humans. Therefore, the resin can be easily molded by a method such as a casting method using a resin solution dissolved in an organic solvent without applying excessive heat or shearing. Therefore, there is no problem due to deterioration or decomposition of the resin during processing. Further, the copolymer resin having a specific ratio of ester units is degradable or disintegratable by microorganisms.

Claims (7)

[Claims] 1. A weight average molecular weight of 1,000 to 10,0.
An aliphatic ester-amide copolymer resin having a range of 00 and being soluble in an organic solvent having low toxicity and high safety to the human body. 2. A weight average molecular weight of 4,000 to 9,0.
The resin according to claim 1, which is in the range of 00. 3. An aliphatic ester-amide copolymer resin,
Formula (1) or Formula (2) -OR₁-CO- (1) (In the formula, R₁Is a linear alkylene group having 1 to 6 carbon atoms or
Is a part of hydrogen atoms of the straight chain alkylene group has 1 carbon atom.
A branched alkylene group substituted with an alkyl group of
Show. ) -OR_Two-OCO-R_Three-CO- (2) (In the formula, R_TwoIs a linear alkylene group having 2 to 6 carbon atoms or
Some of the hydrogen atoms of the straight-chain alkylene group have 1 to 3 carbon atoms.
A branched alkylene group substituted with an alkyl group, R _ThreeIs charcoal
Linear alkylene group having a prime number of 2 to 10 or the linear alkylene group
Part of the hydrogen atoms of is substituted with an alkyl group having 1 to 3 carbon atoms.
Is a branched alkylene group. ) Consisting of
Unit and Formula (3) or Formula (4) —NH—R_Four-CO- (3) (In the formula, R_FourIs a linear alkylene group having 2 to 12 carbon atoms
Alternatively, some of the hydrogen atoms of the linear alkylene group have carbon atoms.
Branched alkylene group substituted with 1 to 3 alkyl groups
Is shown. ) -NH-R_Five-NHCO-R₆-CO- (4) (In the formula, R_FiveIs a linear alkylene group having 2 to 6 carbon atoms
Alternatively, some of the hydrogen atoms of these linear alkylenes are carbon.
Branched alkyl substituted with an alkyl group having 1 to 3 atoms
Ren group, R₆Is a linear alkylene having 2 to 10 carbon atoms
Some of the hydrogen atoms of the groups or their straight chain alkylene are carbon
A branched alkyl substituted with an alkyl group having 1 to 3 elementary atoms
Indicates a xylene group. ) Consisting of an amide unit
The resin according to claim 1 or 2. 4. An aliphatic ester-amide copolymer resin,
The resin according to claim 1, which has biodegradability. 5. The aliphatic ester-amide copolymer resin,
The resin according to any one of claims 1 to 4, which has an amide unit in a proportion of 10 to 80 mol% in the main chain. 6. The organic solvent is an aliphatic alcohol having 6 or less carbon atoms, and the following chemical formula (A) R ₇ (OCH ₂ CH ₂ ) _n R ₈ (A) (wherein, R ₇ has 1 to 4 carbon atoms). Alkyl group, R ₈ is a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, an amino group or an acetyl group, and n is an integer of 1 to 3), an aliphatic glycol ether represented by 2 to 6 carbon atoms , Carbon number 2
The resin according to any one of claims 1 to 5, wherein one kind or a plurality of kinds are selected from the aliphatic sulfoxide of 6 and the aliphatic amide of 2 to 6. 7. A fat comprising the aliphatic ester-amide copolymer resin according to any one of claims 1 to 6 dissolved in an organic solvent having low toxicity and high safety for the human body. Group ester-amide copolymer resin solution.