JPH09165441A - Production of polyhydroxycarboxylic acid resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a biodegradable resin by heating a hydroxycarboxylic acid in the presence of a 1,3-substd. 1,1,3,3-tetraalkyldistannoxane under a reduced pressure to cause the polymn., adding a silane coupling agent to the polymn. system, and further continuting the polymn. SOLUTION: A biodegradable polyhydroxycarboxylic acid resin is obtd. by feeding a hydroxycarboxylic acid (e.g. L-lactic acid) and a 1,3-substd. 1,1,3,3- tetraalkyldistannoxane represented by the formula (wherein R is CH3 , C2 H5 , etc.; X is Cl, Br, NCS, etc.; and Y is Cl, Br, OH, etc.) as the polymn. catalyst into a sample sphere of a glass tube oven, evacuating the sphere to about 50mmHg or lower while rotating it to remove water, heating it to about 120-220 deg.C to conduct the polymn., returning the inside of the polymn. system to normal pressure, and further continuing the polymn. in the presence of a silane coupling agent (e.g. tetrabutoxysilane) in an amt. of 0.001-10 pts.wt. pref. 0.1-10 pts.wt., based on 100 pts.wt. final resin.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a biodegradable resin using a hydroxycarboxylic acid such as lactic acid as a starting material.

[0002]

2. Description of the Related Art A polyhydroxycarboxylic acid obtained by polymerizing a hydroxycarboxylic acid such as lactic acid has already been produced as a biodegradable resin by the following method.
That is, a) After synthesizing a hydroxycarboxylic acid oligomer, a cyclization reaction is performed to synthesize a lactone such as lactide, and after distillation and purification, ring-opening polymerization is further performed. B) After synthesizing the lactic acid oligomer, the molecules are crosslinked with a compound having a functional group such as isocyanate. C) Hydroxycarboxylic acid is subjected to dehydration condensation reaction using molecular sieves in a reaction mixture containing an organic solvent such as anisole.

However, in any of the conventional methods for producing a polylactic acid resin as described above, when a catalyst is directly added to hydroxycarboxylic acid, the catalyst is deactivated, so that dehydration is required first, and a high molecular weight polymer is obtained. On the other hand, you can get
The reaction route is long, the reaction is complicated, and a large number of man-hours are required for the production facility and separation / recovery of organic solvents and catalysts.
There is a problem that the cost becomes large.

[0004]

The problem to be solved by the present invention is to provide a method for producing a polyhydroxycarboxylic acid resin having a short reaction route, a simple reaction, and a small production cost and man-hours. is there.

[0005]

[Means for Solving the Problems] The first invention provides a hydroxycarboxylic acid with 1,3-substituted-1,1,3,1 as a polymerization catalyst.
3-tetraalkyl distannoxane

Embedded image , A heat treatment under reduced pressure, and a silane coupling agent are further added to synthesize the polyhydroxycarboxylic acid resin.

Embedded image It is a manufacturing method of.

[0006]

Embedded image

[0007]

Embedded image

The second invention relates to a hydroxycarboxylic acid,
As a polymerization catalyst, 1,3-substituted-1,1,3,3-tetraalkyl distannoxane is added, heat-treated in an organic solvent, and a silane coupling agent is further added to synthesize. Is a method for producing a polyhydroxycarboxylic acid resin.

The third invention is to use as a polymerization catalyst,
1,3-substituted-1,1,3,3-alkyl group bonded to a tin atom of tetraalkyl distannoxane, methyl group, ethyl group, propyl group, butyl group, octyl group, allyl group, benzyl group, Either a phenyl group or a naphthyl group,
Preferred is the method for producing a polyhydroxycarboxylic acid resin according to the first or second invention, which is a butyl group.

The fourth invention is to use as a polymerization catalyst,
A 1,3-substituted-1,1,3,3-tetraalkyldistannoxane wherein the substituents at the 1,3 position are halogens, thiocyano groups, hydroxyl groups, alkoxy groups, or carboxyl groups; A method for producing a polyhydroxycarboxylic acid resin according to the second or third invention.

A fifth aspect of the present invention is a silane coupling agent,
1st or 2nd or 3rd or 4th invention description which consists of at least 1 type or more of alkoxysilanes, aminosilanes, carboxysilanes, acetoxysilanes, oximesilanes, vinylsilanes, or the oligomer of these compounds. It is a method for producing a polyhydroxycarboxylic acid resin.

A sixth aspect of the present invention is the first or second aspect, wherein the amount of the silane coupling agent added is 0.001 to 50 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the polyhydroxycarboxylic acid resin. Alternatively, it is a method for producing a polyhydroxycarboxylic acid resin according to the third, fourth or fifth invention.

The hydroxycarboxylic acid used in the present invention is an aliphatic carboxylic acid having a hydroxyl group in the molecule,
When it has an asymmetric carbon, it may be in the D-form, L-form or racemic form. Further, two or more kinds of hydroxycarboxylic acids may be used in combination. Further, it is not necessary to remove water from the hydroxycarboxylic acid in advance, and it can be used regardless of the presence of water.

In the present invention, as a condition for heat treatment under reduced pressure, there is no problem if the degree of reduced pressure is 50 mmHg or less, but 15 mmHg or less is more preferable. The heating temperature is 12
0 ° C to 220 ° C is preferable. If the temperature is 120 ° C or lower, the reaction rate becomes extremely slow, which is not preferable. If it is 220 ° C. or higher, the catalyst is decomposed, which is not preferable.

In the present invention, any organic catalyst may be used as long as it has a boiling point higher than that of water and is not compatibilized with water during the polymerization of hydroxycarboxylic acid in a solution. It is preferable that D-limonene has little adverse effect on the environment and human body even if it remains in the resin.

[0016]

Example A glass tube oven GTO-250RS (manufactured by Shibata Kagaku Kikai Kogyo) was used for solventless polymerization,
For polymerization in solution, 200 ml eggplant type flask, T-shaped tube,
A 20 ml eggplant-shaped flask for receiving water and an air cooling tube were used. The GPC device for measuring the molecular weight of the polymer is a high performance liquid chromatograph pump Shodex DS-
4. A differential refractive index detector Shodex RI-71 and a column GPCK806M (manufactured by Showa Denko) were used.

[0017]

[Example 1] 90 in a sample bulb of a glass tube oven
% L-lactic acid 100 mmol (10 g) and 1,3-dichloro-1,1,3,3-
0.01 mmol (0.005 g) of tetrabutyl distannoxane was added, and while rotating the sample sphere, the pressure inside the system was reduced to 1 mmHg using a vacuum pump. After the water is removed, the temperature in the glass tube oven is set to 190 ° C. and the polymerization reaction is performed for 20 hours. The weight average molecular weight of the obtained polylactic acid was 22,0.
00. The temperature of the sample sphere is set to 150 ° C., the pressure in the system is set to normal pressure, 0.3 g of tetrabutoxysilane is added, and the reaction is continued for 8 hours. The weight average molecular weight of the obtained polylactic acid was 30,000.

[Example 2] 90 on a sample sphere of a glass tube oven
% L-lactic acid 100 mmol (10 g) and 1-chloro-3-hydroxy-1,1,3,3-tetrabutyl distannoxane 0.01 mmol (0.0
05g), and while rotating the sample sphere, use a vacuum pump to reduce the pressure in the system to 1 mmHg. After the water is removed
Set the temperature in the glass tube oven to 190 ° C and 2
The polymerization reaction is performed for 0 hours. The weight average molecular weight of the obtained polylactic acid was 27,000. Bring the sample sphere to 150 ° C, bring the system to normal pressure, add 0.3 g of tetrabutoxysilane, and add 8
Perform a time reaction. The weight average molecular weight of the obtained polylactic acid is
It was 33,000.

Example 3 90% L-lactic acid 1 in a 200 ml eggplant-shaped flask
Mol (100 g) and 1,3-dichloro-1,1,3,3-tetrabutyl distannoxane 0.1 mmol (0.05 g) were added, and D-limonene was added.
After adding 100 ml, a T-shaped tube, a 20 ml eggplant-shaped flask for receiving water, and an air cooling tube were attached, and the mixture was heated to reflux and stirred while allowing water to flow out of the system to carry out a polymerization reaction for 24 hours. The weight average molecular weight of the obtained polylactic acid was 44,000. The flask was heated to 160 ° C and tetrabutoxysilane was added.
0.3 g is added and the reaction is continued for 8 hours. The weight average molecular weight of the obtained polylactic acid was 50,000.

Example 4 90% L-lactic acid 1 in a 200 ml eggplant-shaped flask
Add mol (100g) and 1,3-dichloro-1,1,3,3-tetrabutyldistannoxane 0.1mmol (0.05g), decalin 100m
After the addition of 1, a T-shaped tube, a 20 ml eggplant-shaped flask for receiving water, and an air cooling tube were attached, and the mixture was heated under reflux and stirred while allowing water to flow out of the system to carry out a polymerization reaction for 24 hours. The obtained polylactic acid had a weight average molecular weight of 70,000. The flask was heated to 160 ° C and tetrabutoxysilane was adjusted to 0.
Add 3 g and carry out the reaction for an additional 8 hours. The weight average molecular weight of the obtained polylactic acid was 77,000.

[0018]

The obtained polyhydroxycarboxylic acid resin is
Agricultural and horticultural materials, paints for preventing the attachment of shellfish and algae for fishing,
It can also be used as a hot melt adhesive or the like. Also,
Even if it is discarded after use, over time, it is hydrolyzed and decomposed into carbon dioxide, silicon dioxide and water by microorganisms in the soil, etc., and it can be put into a material cycle cycle in a natural environment.

[0019]

EFFECTS OF THE INVENTION Since the present invention is constituted as described above, a polyhydroxycarboxylic acid resin can be easily manufactured.

Claims (6)

[Claims] 1. A hydroxycarboxylic acid to which 1,3-substituted-1,1,3,3-tetraalkyldistannoxane is added as a polymerization catalyst, and the mixture is heat-treated under reduced pressure, and a silane coupling agent is further added. A method for producing a polyhydroxycarboxylic acid resin, which comprises adding and synthesizing. 2. A hydroxycarboxylic acid to which 1,3-substituted-1,1,3,3-tetraalkyldistannoxane is added as a polymerization catalyst, which is heat-treated in an organic solvent, and further a silane coupling agent. A method for producing a polyhydroxycarboxylic acid resin, which comprises synthesizing by adding. 3. 1,3-Substitution-1, used as a polymerization catalyst
The alkyl group bonded to the tin atom of 1,3,3-tetraalkyldistannoxane is any of a methyl group, an ethyl group, a propyl group, a butyl group, an octyl group, an allyl group, a benzyl group, a phenyl group, and a naphthyl group. And preferably,
The method for producing a polyhydroxycarboxylic acid resin according to claim 1, which is a butyl group. 4. 1,3-Substitution-1, used as a polymerization catalyst
The polyhydroxy group according to claim 1, 2 or 3, wherein the substituent at the 1,3 position of 1,3,3-tetraalkyldistannoxane is any of halogens, thiocyano group, hydroxyl group, alkoxy group and carboxyl group. Method for producing carboxylic acid resin. 5. The silane coupling agent comprises at least one kind of alkoxysilanes, aminosilanes, carboxysilanes, acetoxysilanes, oximesilanes, vinylsilanes, or oligomers of these compounds. The method for producing a polyhydroxycarboxylic acid resin according to 2 or 3 or 4. 6. The amount of the silane coupling agent added is 0.001 to 100 parts by weight of the polyhydroxycarboxylic acid resin.
50 weight part, Preferably it is 0.1-10 weight part, The manufacturing method of the polyhydroxycarboxylic acid resin of Claim 1 or 2 or 3 or 4 or 5.