KR20130132083A - Method for manufacturing hydroxypropyl chitosan and compositions for film using the same - Google Patents

Abstract

Provided are a method for producing hydroxypropyl chitosan and a composition for a film produced by using the same. The method for producing hydroxypropyl chitosan comprisies: a synthesis step of putting alkali chitosan and propylene oxide into a hexane solvent to make alkali chitosan and propylene oxide react to synthesize hydroxypropyl chitosan; a refining step of dissolving the synthesized hydroxypropyl chitosan in an acid solutioin; and a drying step of collecting precipitate by filtering after the refining sep and drying the precipitate. Therfore hydroxypropyl chitosan with enhanced filming function produced by the method is produced. [Reference numerals] (S1) Synthesis step of putting alkali chitosan and propylene oxide into hexane solvent and making alkali chitosan react with propylene oxide to synthesize hydroxypropyl chitosan;(S2) Refining step of dissolving synthesized hydroxypropyl chitosan in acid solution and dropping dissolved mixture into cyclohexane or hexane;(S3) Drying step of collecting precipitate by filtering after the refining step, and drying the precipitate

Description

TECHNICAL FIELD [0001] The present invention relates to a process for preparing hydroxypropyl chitosan and a composition for film using the same,

The present invention relates to a process for preparing hydroxypropyl chitosan and a film composition using the same, and more particularly, to a process for producing hydroxypropyl chitosan having improved film-forming ability and a film composition prepared therefrom.

Chitosan (poly-1,4- [beta] -D-glucosamine) is non-toxic, obtained by deacetylation of chitin under basic conditions (Journal of Biomedical Material Research 59, 2002, 585) and biodegradable (Biomaterials 20, ) Polysaccharide.

Chitin, which can be obtained from natural shellfish crust next to cellulose, and chitosan chains obtained by deacetylating it are reported to be chiral and more rigid than cellulose.

Unlike cellulose, chitin at the C-2 position of pyranose ring and chitosan have NHCOH ₃ and NH ₂ groups, respectively.

Among the cellulose derivatives, hydroxypropyl cellulose (HPC) is not only cheap, but also has the following characteristics. 1) It is safe for UV light. 2) Good film forming ability and easy chemical modification. 3) It has biodegradability. 4) Most of the HPC and its derivatives form a mammary and thermotropic liquid crystal phase. Therefore, researches for utilizing HPC as a material for various uses are being actively carried out.

Hydroxypropyl chitosan (HPCTO) obtained by introducing a hydroxypropyl group into chitosan like HPC is expected to be capable of producing a crosslinked gel having a liquid crystal substance and a liquid crystalline order having new characteristics as well as exhibiting properties possessed by HPC have.

However, the HPCTO produced in the prior art reported in the prior art (Polymer (Korea) Vol. 24, No. 3, pp 418-430 (2000)) has low film forming ability due to ion bridging, .

The present invention provides a process for producing hydroxypropyl chitosan having improved film forming ability.

Another object of the present invention is to provide a composition for a film comprising hydroxypropyl chitosan having improved film forming ability.

According to an aspect of the present invention, there is provided a process for preparing hydroxypropyl chitosan.

The production method of hydroxypropylchitosch acid is a process comprising the steps of synthesizing hydroxypropylchitosan by adding alkali chitosan and propylene oxide into a hexane solvent and dissolving the hydroxypropylchitosan synthesized in the acidic solution and then adding cyclohexane or hex And a drying step of recovering the precipitate using the filtration after the purification and drying the precipitate.

The step of synthesizing the hydroxypropyl chitosan may further include removing unreacted materials using water after the reaction, and drying the recovered product by filtration.

The acidic solution may include formic acid, acetic acid or boric acid.

The alkali chitosan is characterized in that it is prepared by adding a metal hydroxide powder to a solution containing chitosan, polyol and water and reacting.

The purification step is characterized in that it is repeated a plurality of times.

The purification step is repeatedly performed so that the concentration of the metal ion is less than 0.5 wt%.

The hydroxypropyl chitosan is in a sol state at room temperature.

Another aspect of the present invention provides a composition for a film. The composition for a film contains hydroxypropylchitosanic acid produced by the above-mentioned process for producing hydroxypropylchitosan, and the hydroxypropylchitosan contains less than 0.5 wt% metal ion.

The hydroxypropyl chitosan is in a sol state at room temperature.

The degree of substitution (DS) of the hydroxypropyl chitosan is 2.47 to 2.52, and the degree of substitution (MS) is 4.9 to 7.8.

According to the present invention, it is possible to produce hydroxypropylchitosan having improved film-forming ability.

The technical effects of the present invention are not limited to those mentioned above, and other technical effects not mentioned can be clearly understood by those skilled in the art from the following description.

1 is a flowchart illustrating a method for producing hydroxypropyl chitosan according to an embodiment of the present invention.
2 is a graph showing the transition temperature values of hydroxypropyl chitosan prepared in Comparative Example 1 and Production Example 1. FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It is to be understood, however, that the present invention is not limited to the embodiments described herein but may be embodied in other forms and includes all equivalents and alternatives falling within the spirit and scope of the present invention.

The terms used in the specification and claims should not be construed to be limited to ordinary or dictionary terms and the inventor may, in accordance with the principle of properly defining the concept of terms to describe his invention, It should be interpreted in terms of meaning and concept consistent with technical thought.

As used herein, the term "ambient temperature" means 15 deg. C to 25 deg.

As used herein, the term " degree of substitution (DS) "means the number of substituted OH and NH among two OH and one NH groups present per glucosamine unit.

As used herein, the term " molar substitution (MS) "means the number of moles of the average propylene oxide introduced per glucosamine unit.

Example  One

1 is a flowchart illustrating a method for producing hydroxypropyl chitosan according to an embodiment of the present invention.

1, hydroxypropyl chitosan is synthesized (S1) by synthesizing hydroxypropyl chitosan by reacting alkali chitosan and propylene oxide in a hexane solvent, dissolving the synthesized hydroxypropyl chitosan in an acidic solution A step (S2) of adding dropwise to cyclohexane or hexane, and a drying step (S3) of recovering the precipitate using the filtration after the purification and drying the precipitate.

Synthesis step (S1) of synthesizing hydroxypropylchitosan is carried out by reacting alkaline chitosan and propylene oxide in hexane solvent.

The alkali chitosan can be prepared by adding a metal hydroxide powder to a solution containing chitosan, polyol and water and reacting. The polyol may be t-butanol or ethylene glycol. The metal hydroxide may be NaOH, KOH or MgOH.

In addition, the step (S1) of synthesizing hydroxypropylchitosan may further include a step of removing unreacted materials using water after the reaction, and a step of drying the recovered product by filtration after the removal.

After the reaction of hydroxypropylchitosan and propylene oxide, water may be used to remove unreacted material, such as unreacted chitosan.

For example, the product is recovered by filtration after reaction of hydroxypropylchitosanic acid with propylene oxide. The recovered product can be removed by 1) precipitating in hot water, 2) tilting and then 3) dissolving in water at room temperature a plurality of times to remove unreacted materials.

However, the hydroxypropyl chitosan produced in the synthesis step (S1) may contain a part of metal ions such as Na ions. In the step of removing unreacted materials using water, the metal ions are not removed. Hydroxypropyl chitosan in which the metal ion is not removed has a film-forming ability lowered by crosslinking by the metal ion.

Therefore, in order to remove the metal ions, a purification step (S2) is required. The purification step (S2) is carried out by dissolving the synthesized hydroxypropyl chitosan in an acidic solution and adding dropwise to cyclohexane or hexane.

The acidic solution may include fomic acid, acetic acid or boric acid. Preferably, the acidic solution may comprise formic acid.

The purification step (S2) may be repeated a plurality of times. Further, the purification step (S2) can be repeatedly performed so that the concentration of metal ions is less than 0.5 wt%. If the concentration of the metal ion is 0.5 wt% or more, it is difficult to form a film because the film forming ability is low.

The concentration of the metal ion means the weight percentage of the metal ion with respect to the total weight of the hydroxypropyl chitosan and the metal ion.

In the drying step (S3), after the purification step (S2), filtrate is used to recover the precipitate, and the precipitate is dried.

For example, the precipitate recovered after the purification step may be dried under reduced pressure.

The dried final product may be in a sol state at room temperature. This is because the content of the metal ion and water remaining in the hydroxypropyl chitosan is reduced through the purification step (S2) and the drying step (S3) to remove the crosslinking substance and the glass transition temperature (T _g ) It is because.

Example  2

The film composition according to one embodiment of the present invention will be described.

The film composition contains the hydroxypropyl chitosan produced by the above-described preparation method, and the hydroxypropyl chitosan contains less than 0.5 wt% of the metal ion.

The metal ion may be Na ion, K ion or Mg ion.

When the content of the metal ion contained in the hydroxypropylchitosan is less than 0.5 wt%, film formation is possible. At this time, as the content of the metal ion decreases, the glass transition temperature (Tg) of the hydroxypropyl chitosan can be lowered because the effect of the crosslinking of the metal ion is reduced.

In addition, the transition temperature and glass transition temperature of cholesteric to liquid phase of hydroxypropyl chitosan are lowered as the molar substitution degree (MS) is increased. It is considered that this is caused by the plasticization of the main chain due to the decrease of the packing density of the side chain group by the increase of the molar substitution degree.

The degree of substitution (DS) of the hydroxypropyl chitosan may be 2.47 to 2.52, and the degree of molar substitution may be 4.9 to 7.8.

Since the hydroxypropyl chitosan contains less than 0.5 wt% of metal ions, when the molar substitution degree is 4.9 or more, the glass transition temperature becomes lower than the room temperature, so that the hydroxypropyl chitosan can be in a sol state at room temperature . In this case, film formation is easier than solid state at room temperature.

In addition, HPCTOs having a molar substitution degree of 4.9 to 7.8 form bicyclic cholesteric phases. For example, HPCTOs with a molar substitution degree of 4.9 form biaxial cholesteric phases, each having an optical pitch ([lambda] _m ) in the wavelength range from about 728 nm to 1090 nm. As another example, HPCTOs having a molar substitution degree of 5.4 to 7.8 form bifunctional cholesteric phases in which the optical pitch is in a wavelength range from about 795 nm to 2400 nm. That is, it is possible to form a thermotropic cholesteric phase having a wide optical pitch. On the other hand, when the molar substitution degree is more than 4.9 but less than 5.4, the optical pitch is decreased, but when the chitosan is cooled at a temperature which is isotropic, a solid phase is formed at room temperature.

Accordingly, the hydroxypropylchitosanic acid produced by the above-mentioned production method is easily formed into a film at room temperature when the molar substitution degree is 4.9 to 7.8, and is applied to a PVA protective film (multifunctional optical film) having an orientation film and a retardation compensation function This is possible.

On the other hand, even when the molar substitution degree is less than 4.9, it can be mixed with polyacrylic acid to be used as a wide view angle protective film and a high hardness optical functional film.

Manufacturing example  One

NaOH powder was added to a solution of chitosan, t-butanol (TB) and water in a weight ratio of 1: 10: 1.4, and the mixture was stirred at room temperature for 1 hour to prepare alkali chitosan.

The prepared alkali chitosan and propylene oxide (PO) were dispersed in a hexane solvent and stirred at 70 ° C under pressure (30 bar) for 16 hours. The weight ratio of alkali chitosan and hexane was 1: 9.5.

After completion of the reaction, the product recovered by filtration was gradually introduced into a large amount of hot water. To the solution H ₃ PO ₄ An aqueous solution (85 wt%) was added to bring the pH to 7, and then the solution was allowed to stand in hot water (85 DEG C to 95 DEG C).

Most of the water was removed by tilting and the product obtained was dissolved in a large amount of water at room temperature.

The aqueous solution recovered by filtration was subjected to 10 repetitions of 1) precipitation in hot water, 2) tilting, 3) dissolution in water at room temperature, and 4) filtration, and the obtained product was dried.

Then, a solution obtained by dissolving a sample treated with water 10 times and dried in formic acid was slowly added dropwise to a large amount of cyclohexane to purify the solution. The solution was stirred for about 3 hours and the precipitate was recovered by filtration. The purification procedure using formic acid and cyclohexane was repeated 6 times.

After the above purification process was repeated, the precipitate collected by filtration was dried under reduced pressure at 130 캜 for 48 hours to prepare hydroxypropyl chitosan having a degree of substitution of 2.47 and a degree of substitution of 4.9.

Comparative Example  One

The procedure of Preparation Example 1 was repeated, but the purification step using formic acid and cyclohexane was omitted.

Experimental Example  One

The color and Na ion content of the samples prepared in Comparative Example 1 and Production Example 1 were analyzed.

As a result, the samples prepared by the comparison 1 showed a light brown color and contained about 3 wt% of Na ions. Furthermore, the color of the samples and the Na ion content did not change even after the water-based removal process was repeated for the samples prepared in Comparative Example 1. In addition, even if a sample in aqueous solution was injected into a large amount of petroleum ether, the product did not precipitate well.

On the other hand, the samples prepared by Preparation Example 1 showed not only brownish but almost no Na ions.

Experimental Example  2

In the production method of Preparation Example 1, the content of Na ions was measured according to the number of times of repetition of the purification step using formic acid and cyclohexane.

The content of Na ions was measured by ICP-OES (Inductively Coupled Plasma-Optical Emission Spectrometers).

Table 1 below is a table showing the Na ion concentration according to cyclohexane repeated treatment. Referring to Table 1, it can be seen that the Na ion concentration continuously decreases as the number of cycles of cyclohexane is increased. Also, when the number of iterations of cyclohexane was 6 times or more, the Na ion concentration was reduced to less than 0.5 wt%.

Number of iterations of cyclohexane Na ion concentration (wt%) One 3.8 2 3.1 3 2.5 4 1.7 5 1.1 6 ~ 0.3 (within the error range) 7 ~ 0.1 (within tolerance)

ICP-OES measurement result

Experimental Example  3

The transition temperature values of the hydroxypropyl chitosan prepared in Comparative Example 1 and Production Example 1 were compared.

2 is a graph showing the transition temperature values of hydroxypropyl chitosan prepared in Comparative Example 1 and Production Example 1. FIG.

2, the glass transition temperature (T _g ) of the hydroxypropyl chitosan prepared in Comparative Example 1 was 47 ° C., the cholesteric-to-solid phase transition temperature (T _s) ) Is 89 ° C, and the isotropic-to-cholesteric phase transition temperature (T _i ) is 182 ° C.

The hydroxypropyl chitosan produced by Preparation Example 1 had a T _g of 23 ° C, a T _s of 57 ° C and a T _i of 153 ° C.

Therefore, the T _g of the hydroxypropyl chitosan prepared by Preparation Example 1 in which the metal ion was removed through the purification step was about 25 캜 higher than the T _g of the hydroxypropyl chitosan prepared by the Comparative Example 1 in which the purification step was omitted Respectively. Also, the temperatures of T _s and T _i of hydroxypropyl chitosan prepared in Preparation Example 1 were lower than those of Comparative Example 1.

Thus, by removing the metal ions remaining in the hydroxypropyl chitosan through the purification step, the transition temperature values are lowered and the film forming ability is improved.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, This is possible.

Claims (10)

A synthesis step of synthesizing hydroxypropyl chitosan by reacting alkali chitosan and propylene oxide in a hexane solvent;
A step of dissolving the synthesized hydroxypropyl chitosan in an acidic solution, followed by dropwise addition to cyclohexane or hexane; And
And recovering the precipitate using the filtration after the purification, and drying the precipitate. The method of claim 1,
The step of synthesizing the hydroxypropyl chitosan comprises:
Further comprising the step of removing unreacted materials using water after the reaction, and drying the recovered product by filtration after the removal. The method of claim 1,
Wherein the acidic solution comprises formic acid, acetic acid or boric acid. The method of claim 1,
Wherein the alkali chitosan is prepared by adding a metal hydroxide powder to a solution containing chitosan, polyol and water and reacting the solution. 5. The method of claim 4,
Wherein the purification step is repeated a plurality of times. The method of claim 5,
Wherein the purification step is repeatedly performed so that the metal ion concentration is less than 0.5 wt%. The method according to claim 6,
Wherein the hydroxypropyl chitosan is in a sol state at room temperature. A pharmaceutical composition containing the hydroxypropyl chitosan produced by the method of claim 1,
Wherein the hydroxypropyl chitosan comprises less than 0.5 wt% metal ion. 9. The method of claim 8,
Wherein the hydroxypropyl chitosan is in a sol state at room temperature. 9. The method of claim 8,
Wherein the degree of substitution (DS) of the hydroxypropyl chitosan is from 2.47 to 2.52 and the molar substitution degree (MS) is from 4.9 to 7.8.

Images