JPS6329000A - Chitin body due to papermaking method - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a chitin-based paper product made of β-chitin that is extremely suitable for uses such as separation membranes, food wrapping paper, and medical materials.

[Prior art]

Chitin is poly(β(1,4)-2-acetamido-2-
It is a polysaccharide with a chemical structure expressed by deoxy-glucan), and is present in the epidermal structure of crustaceans such as crabs and shrimp, and arthropods including insects, and in the cell walls of grains. It is then produced in large quantities. However, while cellulose is widely used in various fields, chitin has hardly been used.

Recently, as a method to effectively utilize chitin,
A method has been proposed in which chitin extracted from the outer shells of crustaceans such as crabs and shrimp is disintegrated in water to prepare a chitin suspension, and then this is made into paper to obtain a chitin paper (Unexamined Japanese Patent Publication No. (Sho 56-68200).

However, the chitin obtained from crustaceans such as crabs and shrimps used in this method is α-chitin in which the molecular chains in its crystals are arranged in an antiparallel manner, and is highly crystalline and tightly packed. Because of its structure, it is hard and does not easily swell in water (R, A, A, Muzzarell
i“Chj, tin”F'ergamon Press
(see 1977).

Therefore, it is difficult to obtain a homogeneous chitin suspension even if α-chitin is disintegrated in water by applying strong mechanical shearing force, and for this reason, the resulting chitin paper product has a poor texture. It has disadvantages in that it has low strength and cannot be made into a thin sheet.

〔the purpose〕

The present invention differs from the conventional α-chitin-based paper products,
It has excellent texture uniformity and excellent strength characteristics,
Moreover, it is an object of the present invention to provide a β-chitin-based paper product that exhibits good transparency.

C Structure] According to the present invention, a chitin-based paper product characterized by being made of β-chitin is provided.

The chitin-based paper product of the present invention uses β-chitin, which has a structure in which the molecular chains in chitin crystals are arranged in parallel, as the main component, and is therefore different from conventional paper products based on α-chitin. On the contrary, it has excellent uniformity of texture, excellent strength characteristics, and good transparency, so it is extremely useful as a thin sheet-like paper product.

Although it is not clear why the paper product of the present invention exhibits such effects, the β-chitin used as the main component is
Unlike α-chitin, which is extracted from crustaceans such as shrimp, it has a flexible structure in which the molecular chains in its crystals are arranged in parallel, and it has the property of easily swelling in water. It easily disintegrates in water to form a stable and uniform chitin suspension, and since this is not granular but fibrous, they intertwine and form a mutually adhesive paper product. It is presumed that a product with excellent texture and strength properties can be obtained by this method.

Next, the present invention will be explained in more detail.

The β-chitin used in the present invention has a structure in which the molecular chains in the chitin crystal are arranged in parallel.

Examples of the raw material for this β-chitin include squid, callus, oligochaete, etc., but the soft carapace of squid is preferable from the viewpoint of easy availability.

β-chitin used in the present invention can be specifically purified as follows.

First, the raw material is washed with water to remove foreign matter, then treated with dilute hydrochloric acid or dilute acetic acid solution to remove inorganic salts, and then heated with dilute alkaline aqueous solution to remove proteins and lipids. Wash this appropriately with water to obtain pure purified β-chitin6
Since squid soft carapace contains almost no inorganic salts, the acid treatment step described above may be omitted, but if desired, it may be treated with dilute hydrochloric acid or dilute acetic acid aqueous solution. The order of the treatment step and the alkali treatment step may be reversed, and these treatments may be repeated.

In the present invention, a paper product can be obtained from this β-chitin in the following manner.

First, an appropriate amount of water is added to purified β-chitin and disintegrated. This disintegration step is preferably carried out by adding 1 to 100 parts by weight of purified β-chitin (equivalent to dry solid content) to 100 parts by weight of water and applying mechanical shear core force. In this case, the device for applying mechanical shear core force is a homomixer,
Examples include household mixers, pulp disintegrators or beaters.

In this disaggregation step, β-chitin is dispersed and floated in water in the form of fibrils, and this can be used as β-chitin paper stock as it is or after being appropriately diluted with water.

In addition, when using dry β-chitin as β-chitin, crush or crush the dry β-chitin in advance using a crusher or pulverizer to obtain fibrous β-chitin, and add an appropriate amount of this material. A β-chitin dispersion is obtained by adding the mixture to water and stirring.

Next, these suspensions or dispersions are treated with a screen, cleaner, etc. to remove fine fibers, fine particles, foreign matter, etc. in the same manner as in ordinary papermaking methods, and then used in the next papermaking process.

In this case, if necessary, the freeness may be adjusted to 5J, and a sizing agent, filler, etc. may be added. In the case of dried chitin, fine particles and fine fibers may be removed by crushing or crushing, followed by a screen or the like.

Next, the β-chitin paper stock obtained in this way is made into paper in the same manner as paper stock obtained from ordinary pulp to form a wet chitin paper product, which is then pressed and dehydrated. ,
A β-chitin paper product is obtained by drying.

In addition, during the disintegration treatment of purified β-chitin, a suspension of β-chitin obtained by mixing a predetermined amount of pulp and disintegrating and beating the mixture, or by disintegrating a pre-beaten pulp slurry, or A mixture of fibrous β-chitin obtained by crushing or pulverizing dry β-chitin can also be made into paper as described above.

In this case, the pulps used can be blended in any proportion, and by this method a β-chitin based paper product consisting of a mixture of β-chitin and cellulose fibers can be obtained.

Therefore, in the present invention, there is no need to particularly limit the blending ratio of pulp, but it is usually in the range of 0 to 1000 parts by weight, preferably 0 to 100 parts by weight, per 100 parts by weight of β-chitin.

In addition, as an alternative method to the above method, when disintegrating purified β-chitin, a predetermined amount of α-chitin obtained from the outer shell of crustaceans such as crabs and shrimps is mixed and the mixture is disintegrated;
- A suspension of chitin mixed with flocculent chitin obtained by pulverizing or crushing dry purified β-chitin can also be made into a paper as described above.

In this case, the α-chitin used can be blended in any proportion, and according to this method, a chitin paper product consisting of a mixture of α-chitin and β-chitin can be obtained. Therefore,
In the present invention, it is not necessary to particularly limit the blending ratio of α-chitin, but usually α-chitin is
It is desirable that the amount of chitin be in the range of 0 to 1.000 parts by weight, preferably 0 to 100 parts by weight.

〔effect〕

Since the chitin-based paper product of the present invention has β-chitin as its main component, it has excellent uniformity of texture and excellent strength properties, unlike conventional paper products whose main component is α-chitin. Moreover, since it shows good transparency, it has extremely high practical value as a thin sheet-like paper product.

Furthermore, a thin paper product made of β-chitin and pulp is a homogeneous mixture of chitin and cellulose fibers, and exhibits properties similar to paper.

Therefore, the thin chitin paper product of the present invention can be widely used in the same applications as general paper, and can also be used as a separation membrane, food packaging paper, etc.
It is also suitable as a medical material.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Squid carapace (approximately 30 cm long) containing 50 weight of water
Cut 300g of the mixture into 1-2cm lengths, add 1.5Q of 1N sodium hydroxide aqueous solution, and stir gently for 2 hours at a temperature of 65-70℃ to remove proteins and lipids. did. Next, the alkaline solution is filtered, washed repeatedly with water until the washing solution becomes neutral, and finally, centrifugal dehydration is performed to produce white purified β-chitin 128 containing 40% water.
I got g. The nitrogen content in this purified β-chitin was 7.1% based on the dry chitin content, and the residue after heating at 900° C. for 2 hours was 0.1 stone or less based on the dry chitin content.

When 2Q of water was added to 80 g of the purified β-chitin and stirred for 10 minutes using a household mixer, the mixture evenly swelled in a fibrous form, and the whole became a uniform slurry.

Take 14g of this, dilute it with water, use a paper machine to grind it with an 80-mesh circular wire with a diameter of 15cII+, layer it with filter paper, press it at a pressure of 3kg/d for 5 minutes, and dry it with air to make a 20μ thick melon. A thin sheet-like paper product was obtained which was translucent and had excellent texture. The basis weight of this thin leaf-like β-chitin paper product is 14 g/ffl, the tensile strength is 20°C, and the relative humidity is 60
．． % condition, it was 2.5 Kg/mrn''.

Example 2 β-chitin slurry liquid 25 after difficult treatment obtained in Example 1
& was removed, and paper was then made in the same manner as in Example 1 to obtain a 40 μm thick, translucent, thin sheet-like paper product with excellent texture. The basis weight of this thin leaf-like β-chitin paper structure is 2
4g/rr? The tensile strength was 3.3 Kg/mm2 under the conditions of 20° C. and 6 parts relative humidity.

Example 3 β-chitin slurry liquid 48 after disintegration obtained in Example 1
After that, paper was made in the same manner as in Example 1 to obtain a thin leaf-like paper product with a thickness of 60 μm, translucent and excellent in texture. The basis weight is 4
0g, /rn, tensile strength is 20℃, relative humidity Jf! :, 6
It was 4.2 Kg/in" under 0% condition.

Comparative Example 1 2Q of water was added to 32g of dried α-chitin obtained by treating the outer shell of a red snow crab, soaked overnight, and then stirred for 30 minutes using a household mixer. 42 g of this chitin dispersion was taken out, and then paper was made and dried in the same manner as in Example 1. The resulting α-chitin paper product had poor texture and a thickness of 80 mm.
mμ, basis weight 39 g/rri', and tensile strength 1.5 Kg/mm'' under conditions of 20° C. and 60% relative humidity.

Comparative Example 2 A portion of 62 g of the chitin dispersion obtained in Comparative Example 1 was taken, and thereafter paper was made and dried in the same manner as in Example 1.

The obtained α-chitin paper product had poor texture, had a thickness of 120 μm, a tsubo of 155 g/m, and a tensile strength of 1.8 Kg/mm 2 at 20° C. and 60% relative humidity.

FIG. 1 shows the relationship between the basis weight and tensile strength of the chitin paper products obtained in Examples 1 to 3 and Comparative Examples 1 to 2.

From FIG. 1, it can be seen that the β-chitin paper obtained from squid carapace has extremely superior strength properties compared to the α-chitin paper obtained from crab shell. In addition, in the case of α-chitin obtained from crab shells, if the basis weight is 39 g/m or less, the strength is low, so it was not possible to make a chitin paper article.

Example 4 The deproteinized β-chitin obtained in Example 1 was dried, and then ground in an ultracentrifuge (manufactured by Nippon Seiki) using a 0.75 mm screen. Obtained flocculent chitin 0.72
Add 100m of water to g, stir gently,
When paper is made and dried in the same manner as in Example 1, the thickness is 110I1.
A chitin paper product having a thickness of 1 μm and a basis weight of 41 g/m was obtained.

Comparative Example 3 100 IIQ of water was added to 0.72 g of purified α-chitin derived from crab shells obtained by crushing under the same conditions as in Example 4, and after gently stirring, paper was made in the same manner as in Example 1. A chitin paper structure could not be obtained.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the basis weight and tensile strength of chitin paper products obtained in the present invention and comparative examples.

Claims (2)

[Claims] (1) A chitin-based paper product characterized by being composed of β-chitin. (2) The chitin-based paper article according to claim 1, wherein the β-chitin is obtained from the soft carapace of squid.