JPH11279323A - Solvent-reclaimed cellulosic sponge molding and its preparation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively utilize natural cellulosic resources containing waste, by foaming a cellulosic base material dissolved in N-methylmorpholin-N-oxide through addn. of a foaming agent, followed by coagulation and removal of the solvent. SOLUTION: A cellulose solvent comprising >=72 wt.% of N-methylmorpholin- N-oxide is heated to 75-150 deg.C. A cellulosic base material and a foaming agent in an amt. of 1-15 pts.wt. based on the cellulosic base material are added to be dissolved to provide a cellulosic dissolved product. After the temp. of this cellulosic dissolved product is raised to 75-150 deg.C to form a sponge article, it is allowed to age at a temp. not higher than the dissolving temp., cooled and solidified, than allowed to age in the atmosphere. Next, it is made free of the liq. and rinsed to give a porous solvent-reclaimed cellulosic sponge molded article having a shape of particle, plate, mat, indefinite article or filler. This will simplify the process, greatly alleviate the accompanying environmental measures, and enable mass production, stable quality and added functions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a solvent-regenerated cellulose sponge molded product using N-methylmorpholine-N-oxide as a cellulose solvent system and a method for producing the same. The sponge molded article is used in various fields as a drug carrier, a medical absorbent, a sanitary article, a bio-related substrate, a kitchen article, a cleaning article, a pet article, a coating article, etc. .

[0002]

2. Description of the Related Art Cellulose sponge bodies are widely used from the safety and biocompatibility of raw materials to chemical carriers, medical absorbents, sanitary articles, bio-related base materials, and everyday kitchen articles. As a method for producing the same, a hydrocolloid foam by freeze-drying (JP-A-57-4735)
No. 5, Japanese Patent Application Laid-Open No. 2-102232), a method of producing viscose sponge in which carbon disulfide is allowed to act on cellulose raw material to form viscose via sodium xanthate, and then mixed with reinforcing fibers. Furthermore, a method for producing a cellulosic sponge using a surfactant in combination (see JP-A-3-52938) is disclosed.

[0003] The above freeze-drying method has poor productivity, and the method for producing cellulose sponge using viscose involves the following steps.
In the viscose production process, a sulfur compound is produced as a by-product, and in the method of mixing viscose with reinforcing fibers, it is difficult to obtain a uniform molded body, and the shape is restricted. However, the rationality of the method for producing a cellulose sponge body using viscose cannot be denied. Therefore, there is a need for a cellulose dissolved material that can be used in place of viscose, and a production method using the same.

It has long been known that tertiary amine oxides, especially N-methylmorpholine-N-oxide, are good solvents for cellulose.
In the publication, a method for obtaining a regenerated fiber using the solvent is also disclosed, but it is merely used for spinning. Further, in JP-A-7-189180 and JP-A-9-296392, only the application of cellulose dissolution composition to paper and the use of impregnation are observed, and when a molded body is formed from the dope composition, It becomes difficult to remove the solvent containing N-methylmorpholine-N-oxide,
This has resulted in narrowing the use of solvent systems containing methylmorpholine-N-oxide.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to obtain molded cellulose sponges having various shapes, a process and steps for producing the same. An object of the present invention is to provide a method for producing a solvent-regenerated cellulose sponge molded article that is environmentally friendly throughout the entire reuse.

[0006]

In order to solve the above-mentioned problems,
It has been found that a solvent containing N-methylmorpholine-N-oxide can be easily removed by forming a porous sponge body at the stage of forming a cellulose molded body. That is, the time required for complete removal of the solvent to form a molded article by the means for producing a solvent-regenerated cellulose sponge molded article is as follows:
It has been drastically shortened, and it has become possible to arbitrarily produce a micro- or macro-molded body having a particle shape, a thread shape, a plate shape, a mat shape, an irregular shape, and a shape forming a filler. Compared with a conventional method, for example, a viscose sponge manufacturing method, the steps are greatly simplified, and accompanying environmental measures can be greatly reduced. In the case of forming a cellulose molded body, the method of positively increasing the porosity at the production stage and facilitating the removal of the cellulose solvent is in line with the so-called paper and nonwoven fabric production principle, and enables mass production, stable quality and It has been found that it is possible to impart functionality and that it is possible to produce cellulose products in shapes that are difficult with paper and nonwoven fabric production methods, and that effective use of natural cellulose resources including waste can be achieved. The invention has been completed.

[0007] That is, the solvent-regenerated cellulose sponge molded article according to the present invention is obtained by dissolving a cellulose solution in a cellulose solvent containing N-methylmorpholine-N-oxide in the form of particles, plates, mats, irregular shapes or fillers. It is formed in a porous sponge body having the following.

The method for producing a solvent-regenerated cellulose sponge molded article according to the present invention is characterized in that a cellulose solution obtained by dissolving a cellulose substrate with a cellulose solvent system containing N-methylmorpholine-N-oxide is used. A method for producing a solvent-regenerated cellulose sponge molded article by forming into a porous sponge body having a particle shape, a plate shape, a mat shape, an irregular shape or a filler shape, wherein the foaming agent is dissolved before, during or after dissolving the cellulose. It is added after dissolution, and then the temperature of the cellulose melt is raised to the foaming temperature to form a sponge body, which is subjected to coagulation treatment and solvent removal to obtain a solvent-regenerated cellulose sponge molded body.

Further, the present invention is a method for producing a solvent-regenerated cellulose sponge molded article according to claim 2, wherein a foaming agent is raised to a foaming temperature and a foaming bath step is performed to form a sponge body.

Further, according to the present invention, there is provided a method for producing a solvent-regenerated cellulose sponge according to claim 2 or 3, wherein the cellulose melt is aged at a constant temperature, and thereafter the solvent is removed to form a sponge. Is the way.

Further, according to the present invention, the calcium carbonate powder is added before, during or after the dissolution of cellulose, and then the calcium carbonate fine powder is dissolved and removed in an acidic treatment bath. This is a method for producing a solvent-regenerated cellulose sponge molded article.

According to the present invention, there is provided a method according to claim 2, 3, 4 or 5.
A method for producing a molded article of a regenerated cellulose sponge, wherein a gel viscosity of a cellulose solution containing N-methylmorpholine-N-oxide is adjusted to carry out a mechanical foaming treatment.

[0013]

DETAILED DESCRIPTION OF THE INVENTION In Japanese Patent Application Laid-Open No. Hei 7-189019, tertiary amine oxides, especially N
A production method for regenerated cellulose spinning with -methylmorpholine-N-oxide is disclosed. Based on these, the present invention dissolves a cellulose base material whose form has been processed as necessary in a solvent system containing N-methylmorpholine-N-oxide, thereby forming a solvent-regenerated cellulose sponge molded body. As a manufacturing process, a cellulose base material adjusting process, a dissolving process, an aging process, a coagulation process, a dewatering process, and the addition of a foaming agent in any of the processes and a foaming process or a mechanical foaming process are combined to regenerate a solvent. It becomes a cellulose sponge molded body.

As the cellulose substrate, wood pulp, non-wood pulp, mercerized pulp, waste paper pulp, wood flour, newsprint, paper and paper products, laminated paper, resin-treated paper, vulcanized fiber, solvent-regenerated cellulose, solvent-regenerated cellulose sponge Cellulosic substrates selected from viscose products and processed products, alkali cellulose products and processed products, cellulose acetate products and processed products, cellulose fillers and the above wastes, and cellulosic materials including cellulose can be used. If necessary, the above-mentioned cut, coarsely crushed, crushed, finely crushed, flocculent, acid-treated and alkali-treated materials can also be used.

As the cellulose substrate, one of the substrates described in item [0014] or a combination of two or more thereof can be used. That is, the chemical properties of the cellulose substrate,
By combining cellulose base materials having different physical properties and shapes, it is possible to adjust the physical properties of the molded product.

As a solvent system for cellulose, a solvent system containing N-methylmorpholine-N-oxide is used. Other solvent-based components include water, ethanol, methanol, butanol, isopropanol, other alcohols, glycols, N, N-dimethylformamide,
N, N-dimethylacetamide, dimethylsulfoxide, N-methyl-2-propyridinone, sulfolane,
Acetonitrile, dimethylethanolamine N-oxide, dimethylhomopyridine N-oxide, peroxide, and antioxidant can be used in combination. The present invention is not limited to solvent-based components other than these N-methylmorpholine-N-oxides. The proportion of N-methylmorpholine-N-oxide in the solvent is preferably at least 72% by weight. Below this, a good cellulose melt cannot be obtained. The dissolution temperature is preferably in the range of 75 ° C to 150 ° C. If the temperature is lower than 75 ° C., a good cellulose solution cannot be obtained. If the temperature is higher than 150 ° C., self-heating of N-methylmorpholine-N-oxide occurs, so that it cannot be used. Further, a method of promoting dissolution at 120 ° C. or lower is more preferable. By adjusting the dissolution degree of cellulose by temperature and time, it is possible to leave a predetermined amount of undissolved fiber and use it as a reinforcing fiber.Various forms and characteristics depending on the combination, blending ratio and blending sequence of the cellulose base material Can be provided.

Azobisbutylnitrile as a foaming agent;
Azodicarbonamide, 5-morpholyl-1,2,2
3,4-thiatriazole, N, N-dimethyl-N, N
-Organic blowing agents such as dinitrosoterephthalamide, azide compounds and the like can be used. When using these foaming agents, a method of dissolving a predetermined amount of the cellulose base material below the decomposition temperature of the foaming agent, and then raising the temperature of the solution to the decomposition temperature of the foaming agent, or different from the solvent system used for dissolving the cellulose The foaming treatment can be performed by raising the temperature of the solution to the decomposition temperature of the organic foaming agent in the foaming bath solution. The addition of these foaming agents can be performed between the cellulose substrate adjusting step and the cellulose substrate dissolving step. In the case of using a foaming agent, it is necessary to sufficiently wash and completely remove the molded body.

As the foaming agent, sodium hydrogen carbonate and ammonium carbonate can be used. Addition of these carbonate inorganic foaming agents is carried out after the dissolution of cellulose is completed.
The temperature is kept at not less than 80 ° C and added.
The foaming is completed in the same manner as in [0017].

The liquid of item [0016] can be used as the foaming bath liquid. However, when the mixing ratio of N-methylmorpholine-N-oxide is in the range of 0% by weight to 70% by weight or less, slow foam coagulation occurs simultaneously with foaming, and a good sponge body is formed. The temperature of the foaming bath liquid is set to 70 ° C. or more and 150 ° C. or less. When such a foaming bath step is provided, a sponge body can be easily obtained.

After adding and using an organic compound in a solvent system and dissolving the cellulose, the dissolved cellulose is aged at a dissolution temperature or lower and then removed to obtain a sponge body.
As organic compounds that can be used in this system, C3 or higher alcohols can be used. When a low boiling point compound is used in combination as the organic compound, vacuum removal can be employed. 90 ° C or higher 1
The method for removing the organic compound dissolved at a temperature of 20 ° C. or lower is [0
[018].

A sponge molded body having micropores can be obtained by aging the dissolved cellulose at a temperature below the melting temperature, cooling and solidifying, and then aging in air, and then removing the solvent.

Calcium carbonate is added during the period from the preparation of the cellulose base material to the dissolution step, and the cellulose dissolution is aged at a dissolution temperature or lower, and then dissolved and removed in an acidic coagulation bath to improve the surface crater. You can get a good sponge body. The addition ratio of calcium carbonate is preferably from 1 part by weight to 15 parts by weight based on the cellulose raw material. If the amount is less than 1 part by weight, the effect is not clear and 1
If it exceeds 5 parts by weight, it will be difficult to remove calcium carbonate. As the oxidizing compound used in the acidic coagulation bath,
Organic and inorganic acids, such as acetic acid and phosphoric acid, can be used.

The sponge having continuous cells can be obtained by adjusting the gel strength of the dissolved cellulose and mechanically stirring and foaming. As a method of adjusting the gel strength, the cellulose content is adjusted to 15 parts by weight or more and 30 parts by weight or less, the gel strength of the cellulose dissolved product is kept high, and the mechanical stirring temperature is kept at 75 to 85 ° C. Sponge body can be obtained.

Chitosan can be used for the purpose of adjusting the gel strength and the sponge strength of the cellulose solution. Polyvinyl alcohol, a cellulose derivative such as methyl carboxycellulose, ethyl carboxycellulose, and a sodium salt thereof which can obtain the same effect can also be used. It is preferable that the raw materials used in combination for this purpose are previously stirred and mixed in a powder state, and dissolved together with cellulose in an NMMO solvent system. By this operation, a homogeneous dissolved composition of cellulose can be obtained. The mixing ratio is 0.05% based on the weight of cellulose.
It is more than weight part. If less than 0.05 parts by weight, no effect is exhibited. If it is at least 0.05 part by weight, there is no particular problem and a sponge body can be formed.

Next, the mixture is coagulated in a coagulation bath and subjected to a dewatering and washing step to complete sponge molded bodies having various shapes such as particles, threads, plates, mats, irregular shapes, and fillers. As the coagulation bath, the liquid of item [0016] can be used. However, the compounding ratio of N-methylmorpholine-N-oxide is in the range of 0 to 70 parts by weight, and in order to increase the solidification rate, the solution temperature is set to 10 ° C. or lower, or
Inorganic acids, organic acids, and salt compounds thereof can be added.

Examples of the regenerated cellulose sponge molded articles having various shapes of particles, plates, mats, irregular shapes and fillers will be described. The scope of the present invention is not limited by these examples.

[0027]

EXAMPLE 1 N-methylmorpholine-N-oxide monohydrate 100
15 parts by weight of cotton as a cellulose substrate and 1 part by weight of chitosan are mixed with pulverized N-methylmorpholine-N-oxide monohydrate, and the mixture is heated to 85 ° C. and left to stand for 30 minutes. Was placed. Thereafter, 0.05 parts by weight of azodicarbonamide was added, and the mixture was extruded and dropped into a glycerin foaming bath at 120 ° C. to perform a foaming treatment. Thereafter, the mixture was dehydrated in water to obtain a solvent-regenerated cellulose foam.
The shape of the molded body could be various shapes such as a particle shape, a plate shape, a mat shape, an irregular shape and a filler shape depending on the extrusion shape.

Example 2 Cotton 100 was used as a cellulose base per 100 parts by weight of ground N-methylmorpholine-N-oxide monohydrate.
5 parts by weight and 10 parts by weight of dimethyl sulfoxide as a solvent component were added to N-methylmorpholine-N-oxide 1
Mix with hydrate, warm to 85 ° C. and let stand for 30 minutes. Thereafter, 0.05 parts by weight of azodicarbonamide was added, and the mixture was extruded and dropped into a dimethyl sulfoxide foaming bath at 120 ° C. to perform a foaming treatment. Thereafter, the mixture was dewatered in water to obtain a solvent-regenerated cellulose sponge molded body. The shape of the molded body could be various shapes such as extruded particle shape, plate shape, mat shape, irregular shape and filler shape.

Example 3 N-methylmorpholine-N-oxide monohydrate 100
10 parts by weight of pulp powder and 1 part by weight of hemp fiber as a cellulose base were mixed with pulverized N-methylmorpholine-N-oxide monohydrate, and the mixture was heated to 85 ° C. Let stand for minutes. Thereafter, the temperature of the melt was lowered to 75 ° C., and mechanical stirring was performed. Thereafter, coagulation and dewatering were performed in water cooled to 10 ° C., to obtain a solvent-regenerated cellulose sponge molded body. The shape of the molded body is maintained before being put into the coagulation / dewatering bath.

Example 4 N-methylmorpholine-N-oxide monohydrate 100
10 parts by weight of pulp powder and 1 part by weight of methylcellulose as a cellulose base were mixed with pulverized N-methylmorpholine-N-oxide monohydrate, and the temperature was raised to 85 ° C. for 30 minutes. It was left still. Then 65 ° C
Ammonium carbonate powder was stirred and mixed by lowering the temperature of the melt until it was extruded into a polypropylene glycol foaming bath heated to 115 ° C, or foamed by dropping,
Thereafter, the mixture was dewatered in water to obtain a solvent-regenerated cellulose sponge molded body. The shape of the molded body could be various shapes such as a particle shape, a plate shape, a mat shape, an irregular shape and a filler shape depending on the extruded shape.

Example 5 N-methylmorpholine-N-oxide monohydrate 100
10 parts by weight of pulp powder, 1 part by weight of sodium carboxymethylcellulose as a cellulose substrate with respect to parts by weight,
20 parts by weight of glycerin were mixed with ground N-methylmorpholine-N-oxide monohydrate, the temperature was raised to 85 ° C., and the mixture was allowed to stand for 60 minutes. Then, after aging at room temperature for 10 hours, the solution was dewatered in water containing 10 parts by weight of ethanol cooled to 10 ° C. to obtain a solvent-regenerated cellulose sponge molded body. The shape of the molded body depends on the shape before being put into the coagulation / dewatering bath.

Example 6 N-methylmorpholine-N-oxide monohydrate 100
8 parts by weight of pulp powder as a cellulose substrate with respect to parts by weight,
2 parts by weight of the solvent-regenerated cellulose sponge was mixed with pulverized N-methylmorpholine-N-oxide monohydrate and 10 parts by weight of calcium carbonate, heated to 85 ° C., and allowed to stand for 30 minutes. . Thereafter, after aging at room temperature for 2 hours, the mixture was coagulated, drained, and dissolved in water containing 5 parts by weight of acetic anhydride cooled to 10 ° C. to obtain a solvent-regenerated cellulose sponge molded body. The shape of the molded body depends on the shape before being put into the coagulation / dewatering bath.

[0033]

According to the present invention, porous cellulose sponge molded articles of various shapes can be easily obtained. A method for producing a solvent-regenerated cellulose sponge molded body that can also contribute to the effective use of cellulose,
A molded product that can be used in many fields.

The present invention can be effectively used as a method for producing an environmentally friendly regenerated cellulose sponge molded product in all of its production steps, production steps and recycling.

Furthermore, the present invention provides a porous sponge body at the stage of forming a cellulose molded body,
The solvent containing -methylmorpholine-N-oxide can be easily removed. That is, according to the method for producing a solvent-regenerated cellulose sponge molded article according to the present invention, the time required for complete removal of the solvent for forming the sponge molded article is drastically reduced, and the particle-like, thread-like, plate-like, and mat-like shapes are obtained. It is possible to arbitrarily produce a micro or macro molded article having an irregular shape and a shape forming a filler.

As compared with a conventional method, for example, a method of manufacturing viscose sponge, the steps are greatly simplified, and accompanying environmental measures can be greatly reduced. In the case of forming a cellulose molded body, the method of the present invention, which facilitates the removal of the cellulose solvent by actively forming a porous material at the production stage, is mass-produced,
It is possible to provide stable quality and functionality, to manufacture a cellulose product having a shape that is difficult with a paper and nonwoven fabric manufacturing method, and to effectively utilize natural cellulose resources including waste.

Claims (6)

[Claims] Claims 1. A cellulose sponge having a particle shape, a plate shape, a mat shape, an irregular shape, or a filler shape formed from a cellulose solution by a cellulose solvent containing N-methylmorpholine-N-oxide. Characterized solvent-regenerated cellulose sponge molded product. 2. A cellulose solution obtained by dissolving a cellulose base material in a cellulose solvent system containing N-methylmorpholine-N-oxide is obtained in the form of particles, plates, mats, irregular shapes or fillers. A method for producing a solvent-regenerated cellulose sponge molded article by forming a porous sponge article having a foaming agent, before adding cellulose, during or after dissolving cellulose, and then adding the foaming agent to the foaming temperature. A method for producing a solvent-regenerated cellulose sponge molded body, comprising raising a temperature to form a sponge body, coagulating and removing a solvent to obtain a solvent-regenerated cellulose sponge molded body. 3. The method for producing a solvent-regenerated cellulose sponge molded article according to claim 2, wherein a foaming bath step is performed to raise the foaming agent to a foaming temperature to form a sponge body. 4. A method for producing a solvent-regenerated cellulose sponge molded product according to claim 2, wherein the cellulose dissolved product is aged at a constant temperature, and thereafter the solvent is removed to form a sponge. . 5. The calcium carbonate powder according to claim 2, 3 or 4, wherein the calcium carbonate powder is added before, during or after the dissolution of the cellulose, and then the calcium carbonate fine powder is dissolved and removed in an acidic treatment bath. A method for producing a solvent-regenerated cellulose sponge molded article. 6. The solvent-regenerated cellulose sponge according to claim 2, wherein the gel foaming of the cellulose solution containing N-methylmorpholine-N-oxide is adjusted to carry out mechanical foaming treatment. Manufacturing method of molded body.