JPH06102736B2 - Polymer composite and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel polymer composite used for polymer membranes and a method for producing the same.

[Conventional technology]

Conventionally, polymer films such as pectin film, chitosan film, carrageenan film and pullulan film have been used for food casings and packaging films.

The polymer film is made, for example, by making a solution of a polymer substance such as pectin, chitosan, carrageenan, pullulan, etc. into a thin layer, drying and solidifying.

[Problems to be Solved by the Invention]

A conventional polymer film lacks resistance (solvent resistance) to water, an aqueous solution, an organic solvent, and the like, and has a problem that it is easily dissolved or broken by water, an acid solution, a base solution, or the like. Further, the polymer membrane is sometimes used for a membrane filter or the like, but in this case, the drawback of weak solvent resistance is also a problem.

Then, this invention makes it a 1st subject to provide the polymer composite_body | complex which has solvent resistance, and provides the manufacturing method of the polymer composite_body | complex which can obtain easily the polymer composite_body | complex which has solvent resistance. Is the second subject.

[Means for Solving the Problems]

In order to solve the first problem, the polymer complex according to the invention of claim 1 is composed of a neutralized salt of chitosan and pectin.

The polymer complex according to the invention of claim 2 is a thin film made of a neutralized salt of chitosan and pectin.

The polymer complex according to the third aspect of the present invention comprises a neutralized salt of chitosan and pectin, and is used as a food casing.

The polymer composite according to the invention of claim 4 further comprises:
Low methoxyl pectin is used as pectin.

In order to solve the second problem, in the method for producing a polymer complex according to the invention of claim 5, an acid solution of chitosan and a pectin solution are mixed to generate a neutralized salt of chitosan and pectin. It is characterized by having a process.

The method for producing a polymer complex according to the invention of claim 6 is characterized in that a polymer complex comprising a neutralized salt of chitosan and pectin is once dissolved in formic acid to form a thin film.

Further, in the method for producing a polymer complex according to the invention of claim 7, a solution of one of an acid solution of chitosan and a pectin solution in a thin layer is brought into contact with the other solution, It is characterized by comprising a step of producing a neutralized salt of chitosan and pectin.

Chitosan is a polyelectrolyte having an amino group in its molecule and having a positive charge when dissolved in an acid. Chitosan is obtained, for example, by deacetylating chitin. The degree of deacetylation of chitosan used in this invention is not particularly limited. According to the research by the inventors,
The degree of deacetylation of chitosan depends on the polymer complex (chitosan-
This is because it is considered that it has almost no effect on the formation of the pectin complex).

Pectin has a carboxyl group in the molecule and is a polyelectrolyte having a negative charge when dissolved in water. Pectin is a high methixyl pectin (hereinafter,
"HMP"), low methoxyl pectin (hereinafter referred to as "LM
Abbreviated as "P"). In this invention, HMP and LMP
Any of the above may be used, but it has a higher production rate of a polymer complex composed of a neutralized salt of chitosan and pectin, has a better acid resistance and alkali resistance, and has a large molecular weight. From the viewpoint of lowering the permeability of the substance, it is preferable to use LMP. However, from the viewpoint of increasing the swelling ratio of the polymer composite, it is preferable to use HMP. The molecular weight that can pass through the thin film of the polymer complex can be controlled by changing the methoxyl content of pectin.

A polymer complex composed of a neutralized salt of chitosan and pectin is produced, for example, as follows. An acid solution of chitosan and a pectin solution are prepared separately and both solutions are mixed in the desired proportions. For mixing, operations such as stirring may be performed. Since the reaction between chitosan and pectin is a neutralization reaction, the reaction time and reaction temperature are not particularly limited.

The mixing ratio of chitosan, acid solution, and pectin solution is not particularly limited in the present invention, and the neutralized salt is formed at any ratio. However, from the viewpoint of increasing the production rate of the neutralized salt, the following is preferable. That is, the pectin structural unit (glucturonic acid) and the chitosan structural unit (glucosamine) react at a ratio of 1: 1, and the degree of esterification of pectin is 1 to 100 and the degree of deacetylation of chitosan is 50 to 100. Then, the molar ratio of chitosan and pectin [P / (P + K)] is It is preferable that Here, P is the number of moles of the pectin monosaccharide per average molecular weight, and K is the number of moles of the chitosan monosaccharide per average molecular weight. If the molar ratio is out of this range, the neutralized salt production rate may be lower.

Chitosan is generally difficult to dissolve in water, but it dissolves in an acid solution, so it is preferable to dissolve it in an acid solution. As the acid solution, an inorganic acid such as hydrochloric acid or an organic acid such as acetic acid is used, and it is preferable to use acetic acid out of hydrochloric acid and acetic acid because the neutralization salt production rate is higher. Moreover, as the pH of the acid solution of chitosan changes from the strongly acidic side to the weakly acidic side,
The production rate of neutralized salts tends to increase. In particular, this tendency is remarkable when HMP is used as pectin. Therefore, in the present invention, it is preferable to set the pH value of the acid solution of chitosan on the weakly acidic side.

Pectin is soluble in water and is preferably dissolved in water, but it may be dissolved in something other than water.

Therefore, chitosan and pectin can be separately packaged and supplied as a material for producing a polymer composite. In this case, chitosan may be left in a solid state or may be dissolved in the acid solution.
Further, pectin may be left in a solid state, but may be in a solution as described above. Further, it is also possible to supply formic acid to be used after the formation of the polymer complex as a unit set.

A precipitate forms when the acid solution of chitosan and the pectin solution are mixed. The precipitate is recovered by a method such as centrifugation or filtration, washed appropriately and dried. The shape of the precipitate depends on the pH of the solution at the time of formation, for example, low pH
In the case of, it is fibrous, and in the case of high pH (under the acidic region of pH 6 or less), it is amorphous.

The precipitate is a neutralized salt of chitosan and pectin.
This neutralized salt is insoluble in water because the amino group of chitosan and the carboxyl group of pectin form an ionic bond and the ionic bond is unlikely to dissociate. The neutralized salt is an organic solvent such as dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMA), or an alkali such as sodium hydroxide or potassium hydroxide. It is also insoluble in a mixed solvent of the solution and an organic solvent such as acetone, and has good solvent resistance. However, the neutralized salt is easily dissolved in formic acid.
Therefore, the polymer complex composed of the neutralized salt can be processed or used by dissolving it in formic acid.

A polymer complex composed of a neutralized salt of chitosan and pectin is used, for example, in a thin film and a food casing. The thin film of the polymer composite includes what is called a film or a membrane, and the shape thereof is not limited to a flat shape, and may be a cylindrical shape.
The thin film of the polymer composite is used, for example, as a filtration film or a casing material. In addition, the casing of the polymer composite, which is a food casing, may be composed of only the composite, but may also contain a colorant and other substances that can be mixed in the food. As the food, for example,
There are kneaded products containing edible proteins such as ham and sausages, but other products may be used. Further, the polymer composite can be made into fibers by applying a spinning method of nylon (polyamide) fibers.

In order to make the polymer composite into a thin film or a food casing, for example, the following method is adopted,
It is not limited to these. The first method is to once dissolve the polymer composite in formic acid, form a thin layer of this solution, and dry and solidify. In the second method, one of the chitosan acid solution and the pectin solution is made into a thin layer, and the thin layer is brought into contact with the other solution to form a neutralized salt of chitosan and pectin. Is produced in the form of a thin film and dried. To thin the solution, apply,
An appropriate method such as a method such as casting, or a method of flowing out a solution in a tubular shape to solidify the solution can be adopted. When an acid dye is used as the colorant, it reacts with the amino group of chitosan, so that it can be colored so as not to lose color even during boiling cooking. Examples of edible acid dyes include red No. 2, 102, 104, 105
No. 106 and No. 106, yellow Nos. 4 and 5, blue Nos. 1 and 2, green No. 3, and the like, but are not limited thereto. When using an edible acid dye, if the same acid dye is added to the pectin solution, when the pectin solution and the chitosan solution are contacted with each other, the acid dye is added to the amino group of chitosan together with the neutralization reaction of pectin and chitosan. Can be attached for coloring. When applying and casting, etc., it is applied to a support with good mold release property, applied to a molded product of food, etc., dipped and attached,
When the fluidized food product is extruded, the solution can be extruded around the extruded product. After the neutralized salt of chitosan and pectin is formed, if necessary,
Washing (or purification) such as washing with water, or an additional step for improving physical properties may be performed.

The polymer complex of the present invention is not limited to one composed only of a neutralized salt of chitosan and pectin, and may contain impurities and other compounds within a range that does not impair the effects of the present invention.

[Action]

The neutralized salt produced by the reaction between chitosan and pectin is
The ionic bond between the amino group of chitosan and the carboxyl group of pectin is strong, it is insoluble in water, acid resistance, base resistance,
Has organic solvent resistance. Therefore, the polymer complex composed of the neutralized salt of chitosan and pectin has good solvent resistance.

〔Example〕

Specific examples and comparative examples of the present invention will be shown below, but the present invention is not limited to the following examples.

In Examples and Comparative Examples, the following pectin and chitosan were used.

HMP LMP Chitosan A Chitosan D (A) Formation of polymer complex when various kinds of pectin, kinds of chitosan and molar ratio are variously changed.

-Examples 1 to 12- To 20 ml of the pectin solution (dissolved in deionized water) shown in Table 1, 20 ml of the chitosan solution (dissolved in 0.2% by weight acetic acid solution) shown in Table 1 was added, and immediately stirred and left at room temperature. And reacted. The product obtained by the reaction is subjected to centrifugation at 10,000 rpm for 10 minutes, the precipitate is taken out, washed with an appropriate amount of 0.2 wt% acetic acid and deionized water, filtered with Toyo Roshi No.6, and at 100 ° C. It was dried overnight in an electric dryer. As a result, a polymer complex (chitosan-pectin complex) was obtained in the yields shown in Table 1.

(B) A first method for obtaining a polymer composite as a thin film.

-Example 13- HMP solution (1000 ppm) was applied on a Teflon (tetrafluoroethylene resin manufactured by DuPont (USA)) sheet laid on a glass petri dish, and in that state, Chitosan D was used.
It was immersed in a solution (1000 ppm) for 10 minutes to react pectin with chitosan. After the reaction, remove from the chitosan solution,
It was dried at room temperature. Then, it was immersed in deionized water for 1 day and then naturally dried, and peeled from the Teflon sheet to obtain a thin film of the polymer composite.

-Example 14- A solution of chitosan A (1000 ppm) was applied on a Teflon (tetrafluoroethylene resin manufactured by DuPont (USA)) sheet laid on a glass petri dish, and HM was used as it was.
It was soaked in P solution (1000 ppm) for 10 minutes to react pectin and chitosan. After the reaction, remove from the chitosan solution,
It was dried at room temperature. Then, in the same manner as in Example 13, a polymer composite thin film was obtained.

-Example 15- A polymer composite thin film was obtained in the same manner as in Example 13 except that LMP was used instead of HMP.

-Example 16-A polymer composite thin film was prepared in the same manner as in Example 13 except that LMP was used in place of HMP, and chitosan D was used in place of chitosan A in Example 14. Obtained.

When the polymer composites obtained in the above Examples were analyzed by infrared absorption spectrum, all the composites showed a decrease in absorption at 1740 cm ^-1 due to the presence of undissociated carboxyl groups of pectin, and an unresolved content of chitosan. 1620 cm ^-1 based on dissociated amino groups
The disappearance of absorption was observed. In addition, absorption at 1600 cm ^-1 , which is considered to be due to an ionic bond between the carboxyl group and the amino group, was observed.

In the above-mentioned embodiment, the time for leaving at room temperature is from 0 to 30.
After various changes up to 0 minutes, there was almost no effect on the formation of the polymer composite.

In addition, when the temperatures of both the pectin solution and the chitosan solution were changed from 10 ° C. to 90 ° C. in each of the above Examples, there was almost no effect on the formation of the polymer complex.

The solvent resistance of each polymer composite of Examples 1 to 16 was examined. Further, the solvent resistance was examined using HMP, LMP and chitosan A as Comparative Examples 1, 2 and 3, respectively. Solvent resistance is DMSO, DMF, DMA, formic acid, water, acetic acid (concentration 0.1N), hydrochloric acid (concentration 0.1N) and sodium hydroxide aqueous solution (concentration 0.
1N) is heated to room temperature (R: 30 ℃) and temperature 50 ℃ for 30 minutes (H), and the polymer complex is immersed in each solvent for an appropriate time to dissolve (×) or not (○). It was judged whether or not it was partially dissolved (Δ). The results are shown in Tables 1 and 2.

As can be seen from Tables 1 and 2, the degree of deacetylation of chitosan did not affect the polymer complex formation. Each polymer complex of the Examples is completely dissolved in formic acid, and when HMP is used,
It was soluble in 0.1N hydrochloric acid, but insoluble in other solvents.

(C) A second method for obtaining a polymer composite as a thin film.

-Examples 17 to 20-250 mg of each polymer complex of Examples 2, 4, 8 and 10 was dissolved in 25 ml of formic acid to prepare a solution. This solution was cast on a Teflon (tetrafluoroethylene resin manufactured by DuPont (USA)) sheet spread on a glass petri dish, and dried at room temperature. Then, it was immersed in deionized water for one day and then naturally dried to obtain a thin film of the polymer composite.

Each of the thin films obtained in the above examples was translucent, had a slightly brownish color, and had a thickness of about 50 to 250 μm.

The thin films of Examples 17 to 20 and the polymers of Comparative Examples 1 to 3 were examined for acid resistance and alkali resistance, and the results are shown in Table 3.

For acid resistance and alkali resistance, thin film in hydrochloric acid (pH = 1.
0, 2.0, 3.0, 4.0, 5.0 and 6.0 respectively) and sodium hydroxide aqueous solution (pH = 8.0, 9.0, 1)
Adjusted to 0.0, 11.0, 12.0 and 13.0 respectively)
Immerse in a suitable time and check for any change in appearance.
And nothing was indicated by a circle.

As can be seen from Table 3, the polymer composites of Examples are superior in acid resistance and alkali resistance to the polymers of Comparative Examples.

The polymer composites of Examples 17 to 20 were examined for swelling property, tensile strength and elongation, and the results are shown in Table 4.

The swelling property was measured by cutting each thin film of the polymer composite into a certain size and weighing it before and after soaking it in deionized water for 1 day, and showing the swelling ratio by weight ratio.

Tensile strength and elongation are shown in Shimadzu Autograph (F245-2
-1). The distance between the grips was 10 mm / min. The film piece had a length of 35 mm and a width of 15 mm, and its thickness was measured using a Sony Micromate (M-30). The tensile strength was calculated from the following formula.

Tensile strength = measured value / cross-sectional area [kg / cm ² ] As can be seen from Table 4, the one using HMP as the pectin showed a weight increase of 390 to 400% when immersed for 1 day, whereas the one using LMP had a weight increase of 120 to 130%.
%, Indicating that the swelling rate is higher when HMP is used. The tensile strength and elongation were higher with HMP than with LMP, which may be due to the average molecular weight of pectin.

The permeability of the substance was examined for each of the polymer composites of Examples 17 and 18, and the results are shown in Table 5.

The permeability of the substance was examined as follows. Using a diaphragm type experimental device in which the central portion was partitioned by a thin film, the thin film was sandwiched by O-rings and insulated from the outside. The effective transmission area of the device was 2.55 cm ² . The experiment was performed at room temperature by a static method. On one side of the membrane, 15 ml of deionized water (1 wt% solution) having different molecular weights dissolved therein was placed, and on the other side, 15 ml of deionized water was placed. Immediately collect 0.1 ml of each solution from both sides of the membrane to measure the initial concentration, and after a suitable time (150 to 200 hours), collect 0.1 ml of both solutions and quantify each sample. did. Samples are glucose, maltose, α
-Cyclodextrin (α-CD) and bovine serum albumin (BSA) were used. Glucose, maltose and α-C
D was quantified by the phenone sulfate method, and BSA was quantified by the Lowry method.

As can be seen from Table 5, the membranes of the examples are substances (solute).
There is a difference in the permeability of LMP, and it is considered that LMP is more dense than that using HMP. From this result, it is considered that the thin film of the polymer complex of the present invention is useful as a filtration membrane for molecular weight fractionation, etc., and the molecular weight can be adjusted more by changing the methoxyl content of pectin. . It should be noted that the degree of deacetylation of chitosan or the pH at the time of complex formation had little effect on acid resistance and alkali resistance, swelling property, and tensile strength and elongation.

(D) A third method for obtaining a polymer composite as a thin film.

-Example 21-LMP solution (2.0 wt%) was made into a cylindrical shape from a nozzle having a circular opening, and chitosan D solution (dissolved in 0.2 wt% acetic acid solution to 1.0 wt%) The mixture was extruded into the above and immersed in the same chitosan solution for 10 minutes to react pectin with chitosan. After the reaction, the chitosan solution was taken out and dried at room temperature. Thereafter, in the same manner as in Example 13, a cylindrical polymer composite thin film was obtained.

-Example 22-In Example 21, red 2 was added to the LMP solution at a ratio of 0.1% by weight.
A thin film of a cylindrical red polymer composite was obtained in the same manner as in Example 21 except that the acid dye was added.

(E) A method for obtaining the polymer composite as a sausage casing.

-Example 23-HMP solution (1000 ppm) and chitosan D solution (1000 ppm) were reacted at a molar ratio of 0.6, purified with a 0.2 wt% acetic acid solution and deionized water, and then dissolved in formic acid to form a cylindrical thin film. The sausage dough was filled in the above casing at a pressure of 6 kg / cm ² , and the sausage with the casing was prepared by a conventional method.

-Example 24-The sausage dough was extruded by a stuffer into a chitosan D solution (1.0% by weight) and dipped. Then, it was immersed in a 2.0 wt% HMP solution for 10 minutes, taken out, washed with water, dried, and then a casing-containing sausage was prepared by a conventional method.

-Example 25-Sausage dough was extruded by a stuffer into a chitosan D solution (1.0% by weight) and dipped. Then, it was immersed in a 2.0% by weight HMP solution containing red No. 2 acid dye at a ratio of 0.1% by weight for 10 minutes, taken out, stoppered with water, dried, and then a casing-containing sausage was prepared by a conventional method.

-Example 26-Sausage dough was extruded by a stuffer into a 2.0% by weight HMP solution and immersed therein. Then, it was immersed in a chitosan A solution (1.0% by weight) for 10 minutes, taken out, washed with water, dried, and then a sausage in a casing was prepared by a conventional method.

-Example 27-Sausage dough was extruded by a stuffer into a 2.0 wt% HMP solution containing 0.1 wt% of Red No. 2 acid dye, and dipped. Then, it was immersed in a chitosan A solution (1.0% by weight) for 10 minutes, taken out, washed with water, dried, and then a sausage in a casing was prepared by a conventional method.

In Example 23, sausage was obtained as in the case of using the conventional casing material, and it was not damaged when the sausage dough was filled.

The sausage dough used in Examples 23 to 27 had the following composition.

When the sausage dough is extruded as in Examples 24-27, the sausage dough may be extruded and simultaneously extruded so that the chitosan solution or the pectin solution is coated around the sausage dough.

〔The invention's effect〕

As described above, the polymer complex according to each of the first to third aspects of the present invention is composed of a neutralized salt of chitosan and pectin, and thus has good solvent resistance.

The polymer composite according to the invention of claim 4 has better acid resistance because it uses LMP.

As described above, in the method for producing a polymer composite according to each of the fifth to seventh aspects of the present invention, a polymer composite having good solvent resistance can be easily obtained.

Continuation of front page (56) References JP-A 61-159430 (JP, A) JP-A 63-36767 (JP, A) JP-A 63-164838 (JP, A)

Claims (7)

[Claims] 1. A polymer complex comprising a neutralized salt of chitosan and pectin. 2. The polymer composite according to claim 1, which is a thin film. 3. The polymer composite according to claim 1, which is a casing for food. 4. The polymer complex according to claim 1, wherein the pectin is low methoxyl pectin. 5. The method for producing the polymer complex according to claim 1, comprising a step of mixing an acid solution of chitosan and a pectin solution to produce a neutralized salt of chitosan and pectin. Method for producing polymer composite. 6. To obtain the polymer complex according to claim 2 or 3, a thin film is formed from a solution obtained by once dissolving a polymer complex composed of a neutralized salt of chitosan and pectin in formic acid. A method for producing a characteristic polymer composite. 7. To obtain the polymer complex according to claim 2 or 3, contact is made with a thin layer of either one of an acid solution of chitosan and a pectin solution and the other solution. And a step of producing a neutralized salt of chitosan and pectin, the method for producing a polymer complex.