KR100242886B1 - A biodegradable polycyclicester grafted lignocellulose derivatives and method thereof - Google Patents

Abstract

The present invention relates to a biodegradable cyclic ester-based polymer graft lignocellulose derivatives and a method for preparing the same.

That is, as a biodegradable cyclic ester polymer graft lignocellulosic derivative represented by the following general formula (I), if it is thrown away by nature after a certain period of use, it is decomposed to microorganisms and does not cause environmental pollution. .

here, Is a lignocellulose derivative in which a part of the reactive groups in lignocellulose are substituted in the range of 5% to 200% increase in lignocellulose: g is a cyclic ester system in the chain of lignocellulosic derivatives. State in which the polymer is grafted: Y is a portion excluding the ester group in the cyclic ester monomer: n is an integer of 5 or more, and indicates the degree of polymerization of the cyclic ester polymer.

Description

Biodegradable cyclic ester polymer graft lignocellulosic derivatives and preparation method thereof

The present invention relates to a biodegradable cyclic ester polymer graft lignocellulosic derivative [Biodegradable Poly (Cyclic Ester) Grafted Lignocellulose Derivatives] and a method for producing the same.

More specifically, the present invention provides a novel cyclic ester-based polymer graft lignocellulose derivatives and derivatives thereof that have a characteristic of being decomposed to microorganisms and causing no environmental pollution when discarded in nature after a certain period of use. To provide a way.

Recently, environmental wastes, especially plastic products that are thrown away in large quantities, are becoming a big social problem. Currently used waste plastics are landfilled, incinerated and recycled. However, the landfilling method has its limitations due to its limited capacity, and incineration wastes energy required for incineration and generates carbon dioxide. In addition to adversely affecting global warming, damage to incinerators is often caused, which raises the question of economic feasibility. On the other hand, recycling is recognized as a very good method, and a lot of research is underway and some studies are being carried out. However, due to problems such as collection, quality control, and standards, the economy is experiencing great difficulties.

On the contrary, efforts have been made to solve the problem of electricity by providing biodegradability or photodegradability to plastic so that it can be automatically circulated after being decomposed by natural microorganisms or sunlight after a certain time of use. In some countries, such as the United States and Italy, legal regulations are mandatory to mandate the use of degradable plastics in packaging and containers.

A representative example of a degradable plastic is a polybeta hydroxybutylate (POLY-β-HYDROXY BUTYLATE) resin synthesized by a microorganism developed by ICI of England, which has excellent mechanical properties and degradability. There is a problem that is difficult to be used in general because it is expensive. In addition, polycarprolactone from Union Carbide Corporation of the United States has been developed and marketed. Although it has excellent degradability, it is not suitable for general use, and its mechanical properties are rather poor and expensive. While trying to solve this problem by using a mixture with polypropylene, polystyrene, etc., there is a disadvantage in that degradability is poor.

Currently, relatively economical decomposable plastics, which are most frequently used, add starch or derivatives to about 10% of polyolefins to provide biodegradability or to add biodegradation accelerators to be biodegradable. However, this also does not satisfy the decomposition characteristics, there are still a lot of problems to be solved in this field.

On the other hand, lignocellulose (lignocellulose) refers to a mixture of cellulose, hemicellulose, lignin, such as wood flour, rice husk, rice straw, etc. It is a polymer composite that has a crystalline structure contributing to mechanical properties as well as being easily decomposed by. As such, although lignocellulose has the potential to be useful as a resource, there are a number of technical problems such as lack of thermoplastic, which has been rarely utilized until now, but it is relatively easy to obtain and the amount is enormous. As it is a waste resource, there is an urgent need for a method that can utilize it usefully.

The present inventors solve the above problems at the same time by efficiently utilizing so-called lignocellulose, such as wood powder, rice hull, etc., which can be obtained very cheaply, that is, not only excellent in decomposition properties and mechanical properties, but also good in economy. As a result of repeated studies to obtain a degradable resin, the present invention has been reached.

An object of the present invention is to provide a novel cyclic ester-based polymer graft lignocellulose derivatives having excellent biodegradability and a method for producing the same.

The present invention is obtained by subjecting at least one or more cyclic ester monomers to a ring-opening polymerization reaction at 100 to 230 ° C with a catalyst in a reaction system containing at least one lignocellulosic derivative. It is characterized by providing a graft copolymer represented by (I), that is, a cyclic ester polymer graft lignocellulosic derivative, and a method for producing the same.

here, Is a lignocellulose derivative in which a part of the reactive groups in the lignocellulose are substituted in the range of 5% to 200% by weight with respect to lignocellulose: g is a cyclic ester type in the chain of the lignocellulose derivative State in which the polymer is grafted: Y is a portion excluding the ester group in the cyclic ester monomer: n is an integer of 5 or more, and indicates the degree of polymerization of the cyclic ester polymer.

Hereinafter, the present invention will be described in detail.

In the present invention, the lignocellulose derivative refers to a substance produced by a chemical modification reaction such as etherification and esterification of reactive groups such as hydroxyl groups contained in lignocellulose, and the preparation method thereof is disclosed in Japanese Patent Application Laid-Open. So 57-103804, So 56-135552, So 57-2360, So 61-215675, So 61-215679, So 61-171714, So 61-138722, So 63-63769 and the like.

The degree of chemical modification of the reactive groups contained in lignocellulose is difficult to assess with the substitutions mentioned in the so-called cellulose derivatives because of the nonuniformity of the chemical composition of lignocelluloses, and thus, Expressed as a percentage increase in weight of the product.

The degree of chemical modification of the lignocellulosic derivatives suitable for the graft ring-opening polymerization of the cyclic ester monomers varies slightly depending on the type of the substituent, but is usually 5 to 200% by weight increase ratio, and is 20 to 100 % Is the most suitable. If less than 5%, a sufficient reforming reaction does not occur, so that the reactant is non-uniform, so that the graft polymerization of the cyclic ester monomer does not occur uniformly, whereas if it exceeds 200%, the graft polymerization of the cyclic ester monomer is too small. Not only does this occur smoothly, but also has the disadvantage of poor biodegradability of the product.

Briefly introducing the manufacturing method of the lignocellulorose derivatives, for example, lignocellulorose derivatives using wood flour, one of lignocellulorose, is finely ground in the presence of a solvent or swelling agent, including water. It is obtained by performing esterification, etherification, and the like on a hydroxyl group contained in lignocellulosic at room temperature or under heating, followed by filtration, washing with water or alcohol, and drying.

In esterification, various acids such as acid halides, dibasic acid anhydrides or aliphatic acids are used, and etherification includes methyl chloride, ethyl chloride, and aryl chlorides. halides such as (allyl chloride), benzyl chloride, epichlorohydrin, and alpha-halogen acids such as monochloro acetic acid, dimethyl acetic acid and diethyl acetate Epoxy compounds such as dialkyl acetic acid such as acetic acid, ethylene oxide and propylene oxide, vinyl compounds activated by negative groups such as acrylonitrile, diazomethane, formaldehyde Organometallic compounds, such as aldehydes, such as a), and titanium alklate, are used. In addition, the reaction is carried out without catalyst or under a catalyst. In the former, a catalyst such as sulfuric acid, pyridinium perchlorate, zinc chloride, and the like, in the latter, alkali such as sodium hydroxide, etc. Catalysts can be used.

Examples of the organic group to be introduced include aliphatic acyl groups such as acetyl group, propionyl group, butyryl group, valeryl group, and carboxy propenoyl. Lower alkyl groups such as dibasic acid monoester groups, benzoyl groups, and other aromatic acyl groups, methyl groups, metal groups, and ethyl groups, aryl groups, and carboxymethyl groups hydroxyalkyl groups such as methyl group, hydroxyethyl group, polyoxymethylene group such as polyoxymethylene group, polyoxyethyleneglycol group, benzyl group, benzyl group, pentyl (pentyl), long chain alkyl group of octyl group, cyanoethyl group, methylene ether group, etc. are mentioned. Moreover, it is also possible to introduce | transduce 2 or more types of such organic groups, for example, an acetyl group and a butyl group. Among the various treatment methods mentioned above, the derivative of lignocellulose suitable for the present invention is considered to be methyl, ethyl, benzyl, aryl, acetyl, hydroxyethyl, carboxy, considering the price of raw materials and physical properties of the final product. It is a chemical modifier which introduce | transduced the monoester group by methyl group, maleic acid, or phthalic acid.

What is necessary is just to carry out ring-opening reaction by a well-known method as a cyclic ester monomer used in this invention. Specific examples include β-propiolactone, β-butyrolactone, α, α-bischloromethyl propiolactone, α, α- Dimethyl-β-propiolactone (α, α-dimethyl-β-propiolactone), δ-valerolactone, β-ethyl-δ-valerolactone, 3 , 4,5-trimethoxy-δ-valerolactone (3,4,5-trimethoxy-δ-valerolactone), 1,4-dioxane-2-one (1,4-dioxane-2-one), Glycolide, lactide, 1,4-dithiane-2,5-dione, trimethylene carbonate, neophene Neopentylene carbonate, ethylene oxalate, propylene oxalate, ε-caprolactone, α-methyl-ε-caprolactone (α-methly-ε- caprolactone), β-methyl-ε-caprolactone, β-methly-caprolactone, γ-methyl-ε-caprolactone, 4-meth -7-isopropyl-ε-caprolactone (4-methyl-7-isopropyl-ε-caprolactone), 3,3,5-trimethyl-ε-caprolactone (3,3,5-trimethyl-ε-caprolactone), Cis-disalicylide, trisalicylide, di-0-cresotide and the like.

Among these cyclic ester monomers, it is preferable to use ε-caprolactone which is industrially easy to obtain, easy to handle, and excellent in solubility with lignocellulosic derivatives.

The cyclic ester polymer graft lignocellulosic derivatives in the present invention are catalysts which are generally used for ring-opening reaction of cyclic esters in the presence of at least one or more lignocellulosic derivatives, for example, organic acids, inorganic acids, and organic tin. Catalysts such as compounds, organic acid tin salts, alkali metals, organic alkali metal compounds, alkylaluminum compounds, organotitanium compounds, and halogen compounds such as tin chloride (Reference: “Course Polymerization 7. Ring-opening polymerization (II)” P.104 -P.128, issued by Chemical Co., Ltd., 1973), can be obtained by ring-opening polymerization of a cyclic ester monomer for about 0.1 to 100 hours in the temperature range of 100 to 230 ° C.

It is also possible to mix and react two or more types of above-mentioned cyclic ester monomers here.

In general, if the reaction temperature is increased, the reaction rate is faster, but the lignocellulosic derivatives are thermally decomposed, which leads to a deterioration in physical properties and a dark brown color. Therefore, the thermal properties of the lignocellulosic derivatives to be used in the reaction are considered. It is recommended to select the reaction temperature within the range of 100 ~ 230 ℃.

In general formula (I), the polymerization degree n of a cyclic ester polymer is about 5-5,000, Preferably it is about 50-1,000. If n is less than 5, the crystal structure of the lignocellulosic derivatives is not changed significantly, and the physical properties of the lignocellulorose derivatives having high strength and elongation are extremely small and brittle are not improved.

On the other hand, US Patent No. 3,797,690, US Patent No. 3,860,538, US Patent No. 4,121,025, US Patent No. 4,461,853 to further impart photodegradability to the cyclic ester polymer graft lignocellulose derivatives in the present invention. Known photodegradation accelerators such as cobalt dimethyl-diti, as shown in U.S. Patent No. 3,676,401, U.S. Patent No. 2,455,286, U.S. Patent No. 3,083,184, Japanese Patent Application No. 48-54153, Small 50-21079, Small 50-34340 Fatty acid metal carboxylates, such as cobalt dimethyldithiocarbamate, metal dialkyldithiocarbamate, cupric acetate, zinc stearate, ferric acetylacetonate, etc. ), Metal acetylacetonate (cobaltous acetylacetonate), anthraquinone (anthraquinone) and the like Derivatives, benzophenone and its derivatives, vinyl-ketone copolymers (ecolyte atlantic, product name: ECOLYTE), ethylene-carbon monoxide copolymers (Union Carbide, product name: DXM-439), etc. may be mixed and used. Do.

The obtained cyclic ester-based polymer graft lignocellulosic derivatives can be processed by a related molding apparatus and molding method such as known extrusion, injection, etc., and can be made into films, foams and other molded articles. In addition, it is possible to mix additives such as heat stabilizers, ultraviolet absorbers, antistatic agents, pigments, fluorescent agents, fillers, etc. according to known methods in the production of such molded articles.

Also known polymers, for example, polyethylene, polypropylene, polystyrene, polyvinylchloride, aliphatic or aromatic polyester, polyamide, etc. in view of other physical properties and economic considerations It is also possible to mix and use.

As described above, the polymers obtained by the present invention have excellent mechanical properties and are not easily decomposed by microorganisms in nature and do not cause environmental pollution. Can be.

EXAMPLE

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1-5

(1) Preparation of Methylated Wood Powder

Methylated wood flour was prepared as one of the lignocellulosic derivatives. First, 50 g of dried radiata pine wood powder (20 to 60 mesh) is placed in a 1 L reaction flask and 500 ml of toluene is added thereto. Subsequently, 40 g of caustic soda is added as a 40% aqueous solution, stirred at room temperature for 1 hour, and micelle-ized. Thereafter, 60 ml of methyl iodide (methyl iodide) was added, the vessel was sealed, the temperature was raised to 80 ° C, and reacted for 3 to 6 hours. When the stirrer is stopped at the end of the reaction, the reaction system is separated into two layers so that the homologous toluene is inclined to be removed, and the mixed solution of acetic acid acetone / methanol (volume ratio 3: 7) is injected and stirred to neutralize and the supernatant is removed. Excess acetone was added in the same form, stirred, washed twice, and then dried in a hot air dryer at 60 ° C. for one day and finally vacuum dried at 50 ° C. to obtain a sample. The obtained methylated wood powder was an orangeish yellow powdery solid with a weight increase rate of 10%.

(2) Preparation of poly (ε-caprolactone) graft methylated powder

Poly (ε-caprolactone) graft methyl saponified powder was prepared as one of the cyclic ester polymer graft lignocellulosic derivatives.

First, 100 parts by weight of ε-caprolactone containing 50 ppm of antimony trichloride was introduced while flowing dry nitrogen into a reactor equipped with a stirrer, a reflux cooler, and a thermometer, and then 100 parts by weight of the methyl wood powder previously dried sufficiently. Apply slowly while The temperature is raised to 150 ° C. with sufficient stirring and the reaction is carried out at 150 ° C. for 10 hours. Thereafter, the mixture was cooled to 70 ° C and dissolved by adding 300 parts by weight of dimethylformamide. When the obtained solution is slowly added dropwise while stirring 3,000 parts by weight of methanol contained in the beaker, a sample is obtained in a solid state. This is dried in a hot air dryer and a vacuum dryer to obtain a final sample. The sample obtained was dark yellow and the yield was 93%.

As shown in Table 1, the amount of methylated wood flour and ε-caprolactone was adjusted at various ratios to prepare poly (ε-caprolactone) graft methylated wood powder for various compositions. The sample obtained was dark yellow or pale brown and the yield was 90-95%.

(3) measurement of physical properties

The obtained sample was molded into a film having a thickness of about 100 mu on a hot press plate, and the following physical properties were measured.

1) Melt Index (Melt Idex)

Melt Idex (g / 10min) of the sample was measured according to ASTM D 1238.

2) tensile properties

The strength (Kg / cm ² ) and elongation (%) at break of the sample were measured according to ASTM D 638. Tensile Speed: 500mm / min, Measuring Temperature: 23 ± 1 ℃

3) biodegradable

After cutting the sample to a certain size, using agar as a medium, aspergillus niger, penicillum funiculosum, trichoderma sp and trichoderma sp. Biodegradation properties were measured by spraying a mixed mycelium suspension of Lularia Pullulans (1) and 4 weeks after the fungus was covered with the sample as follows.

0%: 0 10% or less: 1

10 to 30%: 2 30 to 60%: 3

60 to 100%: 4

TABLE 1

[Examples 6 to 10]

(1) Preparation of Benzylated Wood Powder

Benzylated wood flour was prepared as another example of the lignocellulosic derivative. In the preparation of the methylated wood powder was prepared in the same manner except using 150ml benzyl chloride instead of 50ml methyl iodide etherification agent. The obtained benzylated wood powder was in the form of a yellow powder with a weight increase of 50%.

(2) Preparation of Poly (ε-caprolactone) Graft Benzylated Wood Powder

The benzylated wood flour was subjected to ring-opening reaction of epsilon -caprolactone in the same manner as in Examples 1 to 5 (2) to obtain poly (ε-caprolactone) graft benzylated powder of various compositions as shown in Table 2. Prepared.

(3) measurement of physical properties

About the obtained sample, it carried out similarly to the method mentioned in Examples 1-5 (3), and measured physical property, The result is shown in Table 2.

TABLE 2

[Examples 11-15]

(1) Preparation of Acetylated Wood Powder

As another example of lignocellulosic derivatives, acetylated wood flour was prepared. To 10 g of dried tropical keruing wood flour (20 to 60 mesh), 6.0 ml of acetic anhydiride and 40.0 ml of acetic acid were added and allowed to stand overnight at room temperature. Subsequently, the acylating agent which mixed 100.0 ml of acetic anhydrides, 60.0 ml of acetic acid, and 0.2 ml of perchloric acid was cooled about -10 degreeC, and it added to the pretreated wood powder. The reaction was carried out in a 300 ml round bottom three neck flask. After mixed-acid injection, it was left to stand at room temperature for 1 hour and reacted for 6 hours while stirring at 30-45 degreeC. After the reaction, the mixture was washed with water, filtered through a glass filter, and prepared in the same manner as in the preparation of the methylated wood powder. The obtained acetylated wood flour was the same as the wood color, and the weight increase rate was 60%.

(2) Preparation of Poly (ε-caprolactone) Graft Acetylated Wood Powder

By using the acetylated wood powder in the ring-opening reaction of ε-caprolactone in the same manner as in Examples 1 to 5 (2) to prepare a poly (ε- caprolactone) graft acetylated wood powder of various compositions as shown in Table 3 It was. The sample obtained was pale yellow and the yield was about 90 to 95%.

(3) measurement of physical properties

Physical properties of the obtained samples were measured in the same manner as described in Examples 1 to 5 (3), and the results are shown in Table 3.

TABLE 3

[Examples 16-20]

(1) Preparation of arylated chaff

To about 30 g of dried rice husk powder (20 to 60 mesh), 50 g of 40% caustic soda prepared in advance was added and impregnated, and left for one day to obtain an alkali treated rice husk. Subsequently, the obtained alkali-treated chaff was transferred to a stainless pressure reactor, 400 ml of aryl fluoride was added and reacted at 80 ° C. for 3 hours. After completion of the reaction, the reaction product was added to an excess of methanol / water (1/4 by volume) mixture and washed sufficiently with the same solution several times. Finally it was filtered through a glass filter and dried in the same manner as in the methylated wood powder preparation to obtain the final allylated rice husk.

The sample obtained was dark yellow powder with a weight gain of 130%.

(2) Preparation of poly (β-butyrolactone) graft arylated chaff

Except for using the arylated chaff and tributyl titanate in place of the polymerization catalyst tin chloride, and β-butyrolactone in place of ε-caprolactone, Table 4 is the same as in Examples 1 to 5 (2). Various compositions of poly (β-butyrolactone) graft arylated wood powder as shown were prepared. The obtained samples were all dark yellow and the yield was about 90 to 93%.

(3) measurement of physical properties

About the obtained sample, it carried out similarly to the method mentioned in Examples 1-5 (3), and measured the physical property, and the result is shown in Table 4.

TABLE 4

Comparative Examples 1 to 6

For reference, in Comparative Examples 1 to 4, the lignocellulose derivatives in a state in which graft polymerization was not performed using cyclic esters, for example, each of the samples obtained in Examples 1 to 20 (1), were carried out in Examples 1 to 5 (3). The film was obtained in the same manner as described in) and the physical properties thereof were measured.

In Comparative Examples 5 and 6, a film was prepared using the same method for the low density polyethylene (LDPE, Samsung General Chemicals, product name: 530G) and the high density polyethylene (HDPE, Samsung General Chemicals, product name: 120A) resins, which are frequently used for general packaging films. The physical properties were measured. The obtained results are shown in Table 5. The samples in Comparative Examples 1 to 4 have some excellent biodegradability, but the melt index is so small that the workability is extremely poor, and the tensile strength is high and the elongation is extremely low. It can also be seen that polyethylene has very poor biodegradability.

TABLE 5

Claims (6)

Biodegradable cyclic ester polymer graft lignocellulosic derivative represented by the following general formula (I) Where [X] is a lignocellulose derivative in which a part of the reactive groups in the lignocellulose is substituted in a range of 5% to 200% increase in lignocellulose, and g is a lignocellulose derivative. State where the cyclic ester polymer is grafted to the chain: Y is the portion of the cyclic ester monomer excluding the ester group: n is an integer of 5 or more, and indicates the degree of polymerization of the cyclic ester polymer. The organic group, wherein the organic group substituted into part of the reactive group as lignocellulose is aliphatic acyl group, dibasic acid monoester group, aromatic acyl group, lower alkyl group, aryl group, carboxymethyl group, hydroxyalkyl group, poly At least one or more of an oxyalkylene glycol group, a benzyl group, a long chain alkyl group, a cyanoethyl group, and a methylene ether group. The method for producing a biodegradable cyclic ester polymer graft lignocellulose derivative according to claim 1, wherein wood flour, rice hull, and rice straw are used as lignocellulosic. The cyclic ester monomer is β-propiolactone, β-butyrolactone, α, α-bischloromethylpropiolactone, α, α-dimethyl-β-propiolactone, δ-valero Lactone, β-ethyl-δ-valerolactone, 3,4,5-trimethoxy-δ-valerolactone, 1,4-dioxan-2-one, glycolide, lactide, 1,4-diti AN-2,5-dione, trimethylene carbonate, neopentylene carbonate, ethylene oxalate, propylene oxalate, ε-caprolactone, α-methyl-ε-caprolactone, β-methyl-ε-capro Lactone, γ-methyl-ε-caprolactone, 4-methyl-7-isopropyl-ε-caprolactone, 3,3,5-trimethyl-ε-caprolactone, cis-disalicylide, trisalisilide, Biodegradable cyclic ester-based polymer graft lignocellulosic derivatives, characterized in that di-0-cresated. Biodegradable cyclic ester polymer graphs represented by the following general formula (I) obtained by subjecting at least one cyclic ester monomer to a ring-opening polymerization reaction at 100 to 230 ° C. together with a catalyst in the presence of at least one lignocellulosic derivative. Method for producing trilignocellulose derivatives. here, Is a lignocellulose derivative in which a part of the reactive groups in lignocellulose are substituted in the range of 5% to 200% increase in lignocellulose: g is a cyclic ester system in the chain of lignocellulosic derivatives. State in which the polymer is grafted: Y is a portion excluding the ester group in the cyclic ester monomer: n is an integer of 5 or more, and indicates the degree of polymerization of the cyclic ester polymer. The biodegradation method according to claim 2, wherein the catalyst of the ring-opening polymerization reaction is a halogen compound such as organic acids, inorganic acids, organic tin compounds, organic acid tin salts, alkali metals, organic alkali metal compounds, alkylaluminum compounds, organic titanium compounds, tin chlorides, and the like. Method for preparing a cyclic ester polymer graft lignocellulosic derivative.