JP2007077320A - Cellulose sponge and method for producing cellulose sponge product or commodity - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide cellulose sponge which does not have a problem of mold growth or the like as a new cellulose sponge commodity or product form, and almost solves the problems of contracting and staining in comparison with an original size or original shape just after produced as the cellulose sponge, and can especially optimally be used for the uses of medical equipments, and to provide a method for producing the same. <P>SOLUTION: This cellulose sponge is characterized in that the whole shape of the cellulose sponge is freeze-dried and held in a product form or commodity form. The method for producing the cellulose sponge product or commodity comprises supplying a cellulose sponge molded article produced in a production process in a wet state to a freeze-dry process as such in a state holding the water of the wet state to form the product form or commodity form. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cellulose sponge and a method for producing a cellulose sponge product or product.

  Cellulose sponge is generally known as a highly functional material consisting of cellulose (fibrin) derived from pulp and natural fibers such as flax and cotton that are added appropriately as reinforcing fibers. It is used for sponges for wiping moisture when washing dishes at home, and for washing and wiping plates and films in the photographic and platemaking fields, as well as for mops and puffs.

Such cellulose sponge is substantially made of 100% natural material, and since cellulose has a hydrophilic group (OH group), it has a property that it is easily compatible with moisture. It has excellent properties as described in (7).
(1) Water-absorbing ability Having a hydrophilic group makes it easy to become familiar with water, and it has self-water-absorbing property by capillary action due to microbubbles and can quickly absorb water. In particular, because of the continuous bubbles, moisture can be taken into almost all the bubbles, and generally has a water absorption power 20 to 30 times its own weight. It retains the absorbed water appropriately and does not flow down.
(2) Heat resistance Heat resistance is higher than that of urethane-based sponge, and there is generally no change in physical properties up to about 140 ° C.
(3) Chemical resistance Stable against common organic solvents.
(4) Flexibility Since the surface becomes soft in the wet state, it is difficult to damage the object.
(5) Biodegradability Since the composition is only natural cellulose and natural fiber, it is decomposed by microorganisms in the soil. It also exhibits excellent performance as a culture carrier for microorganisms.
(6) Buffering characteristics There is moderate elasticity in the wet state.
(7) Non-polluting flammability No toxic gas is generated during combustion, and only a small amount of ash is left behind.

  Taking advantage of these characteristics, as mentioned above, cellulose sponge has been developed into various applications and products, and new applications include porous beads, cushioning materials, paint rollers, abrasive materials, kitchen sponges, etc. Have been proposed (see Patent Documents 1-4, etc.).

  Recently, new applications are being developed, and one of the applications that attracts attention is the use of medical devices and medical device materials (hereinafter referred to as “medical devices” that utilize the above-mentioned properties). In the present invention, these are collectively referred to as “medical device applications”).

  However, there is a problem when using cellulose sponge as a material in the medical device field. Generally, cellulose sponge is completely wet during the manufacturing process, so the manufacturing process is completed. After that, the finished cellulose sponge is also in a wet state (generally, a wet state with a moisture content of about 60%).

  Such a wet cellulose sponge product is sealed and packaged in a wet / wet state as it is, commercialized and commercialized, and put on a sales route as usual. In that case, an antifungal agent is applied to prevent the adhesion and propagation of mold.

  In general, such an antifungal agent is, for example, a quaternary ammonium salt or OPP (orthophenylphenol), and the cellulose sponge provided with the antifungal agent cannot be used for medical device applications.

  On the other hand, with the aim of preventing the occurrence of mold without specially providing antifungal agents and other chemicals, we are also developing products in which the finished cellulose sponge product in a wet state is dried immediately after production. However, in the conventional method of drying in the drying chamber, even if the drying is performed slowly at a low temperature, the sponge shrinks by about 10 to 20% in length in each direction. In terms of form, there is also a disadvantage that distortion occurs.

  For example, when a sheet-like product is dried, the cross section is distorted three-dimensionally so as to draw an arc, and it is difficult to say that the individual product form after such distortion is constant. There are problems such as product image as an industrial product, points of individual packaging and difficulty in packing and transporting a plurality of items together, and the dried product is further dimensioned appropriately. However, there was a problem that it was not possible to cut to the size and form as planned.

  Against this background, when cellulose sponge is conventionally used for medical device applications, it is not possible to use fungicides or the like, so the wet state immediately after production as described above is immediately dried. Commercialization and commercialization are being carried out. However, as described above, when dried, the volume contracts to about 60%, and distortion is caused in terms of form and shape, which is not preferable.

  Conventionally, even if the shape shrinks and is distorted and dried, if it is re-hydrated, it will return to its original size and shape. However, if you want to use it while it is dry, or if you want to use it as it is after it is cut and dried, or if you want to use it again with moisture, the shape other than the thickness changes. There was an inconvenience that there were some cases, and it was not desirable in terms of products and products.

  In particular, in medical equipment applications, there are various usage scenarios, such as when you want to use the product as it is dry, or when you want to use it as it is or after it has been cut and dried again. This is very different from the field where strictness is not required in terms of form and shape.

Incidentally, cellulose sponges that have been used in medical device applications have been used for adhesive bandages, low-frequency treatment pads, and the like due to their gentle touch and excellent water absorption. In particular, in the case of an adhesive bandage pad, what was pressed and formed into a thin pad sucks blood when it is applied to the wound and restores it to its original thick shape. It has been. That is, in such an application (an application in which shape restoration is expected), what the original state is is important because it affects the expression of the expected performance.
JP-A-5-305967 JP-A-7-236607 JP-A-7-185448 JP-A-7-11007

  In view of the above-mentioned points, the object of the present invention is to provide a novel cellulose sponge product / product form, which does not have the problem of mold generation and the like, and the original dimensions and shape immediately after being produced as a cellulose sponge. It is an object of the present invention to provide a cellulose sponge that can be used optimally for medical device applications, and a method for producing the same, in which the problems of shrinkage and distortion in comparison are substantially solved.

The cellulose sponge of the present invention that achieves the above-mentioned object has the following constitution (1) or (2).
(1) A cellulose sponge characterized in that the entire shape is freeze-dried and held to form a product.
(2) A cellulose sponge characterized in that the entire shape is freeze-dried and held into a product form.

In addition, the cellulose sponge of the present invention preferably has the following specific structures (3) to (5).
(3) The cellulose sponge as described in (1) or (2) above, which is used for medical equipment.
(4) The above (1), (2) or (3), wherein the cellulose sponge comprises cellulose and cotton, flax, ramie, pulp as a reinforcing fiber alone or in combination thereof The cellulose sponge as described.
(5) The cellulose as described in (1), (2), (3) or (4) above, which is formed into a product form or a product form without being given a chemical for preventing mold generation sponge.
(6) The above-mentioned (1), (1), wherein a cellulose sponge is formed in a large size, then cut into small dimensions, and then freeze-dried to form a product or product. 2) The cellulose sponge according to (3), (4) or (5).
(7) The above (1), (2), (3), (4), (5) or (5) characterized by being freeze-dried and then pressed to form a product or product (6) The cellulose sponge as described.

In addition, the method for producing a cellulose sponge product or product of the present invention that achieves the above-described object has the following configuration (8).
(8) The cellulose sponge molded body manufactured in the manufacturing process in a wet state is subjected to a freeze-drying process with the moisture in the wet state maintained, and is made into a product form or a product form. Cellulose sponge product or product manufacturing method.

  According to the present invention according to claim 1, as a product / product form of a novel cellulose sponge, there is no problem of mold generation, etc., and compared with the original dimensions and shape immediately after being produced as a cellulose sponge. The present invention makes it possible to obtain a novel cellulose sponge that can be used optimally for medical device applications, in particular, in which the problems of shrinkage generation and strain generation are substantially solved.

  Further, according to the cellulose sponge product or the method for producing a product of the present invention according to claim 8, there is no problem of mold generation as a novel product / product form of the novel cellulose sponge, and immediately after being produced as a cellulose sponge. In particular, there is provided a method for producing a cellulose sponge that can be used optimally for medical device applications, in which the problems of shrinkage and distortion as compared with the original size and shape of the film are almost solved.

  Hereinafter, the cellulose sponge of the present invention and the method for producing the cellulose sponge product or product will be described in more detail.

  The cellulose sponge of the present invention is characterized in that the entire shape is freeze-dried and held, and is formed into a product form or a product form.

  The cellulose sponge used in the present invention may be a cellulose sponge produced by a conventional production process as it is, and in particular, the cellulose sponge has generally left the production line because the production process is in a wet state. What is necessary is just to use the cellulose sponge of the wet state immediately after that for a freeze-drying process as it is.

  According to the study by the present inventors, the product manufactured in a wet state and freeze-dried as it is has no problem of mold adhesion and propagation, and is further dried over a long period of time. In the case of the present invention, the problem of shrinkage and distortion is substantially eliminated in the present invention.

  Specifically, in the freeze-dried cellulose sponge of the present invention, even if there is a change in size and shape due to the freeze-drying, the shrinkage is at most several percent (shrinkage: 2 to 10%). In addition, almost no morphological distortion occurs. As a result, it becomes possible to manufacture cellulose sponge products / commodities with planned quantities and shapes.

  The cellulose sponge according to the present invention is most preferably used for medical device applications where strictness is required rather than just the water-absorbing material field where strictness is not required in size, shape and the like.

  In order to give strength to the cellulose sponge, the cellulose sponge of the present invention comprises cellulose as a base fiber and cotton (cotton), flax, ramie, pulp as a reinforcing fiber, or a combination thereof. It is preferable. Preferably, about 50 to 20% by weight of a reinforcing fiber such as cotton is used with respect to 50 to 80% by weight of cellulose.

  The cellulose sponge according to the present invention employs freeze-drying as a method for preventing the occurrence of mold, and the basic technical idea is not to use a mold generation preventing agent. Quaternary ammonium salts and OPP (ortho) (Phenylphenol) is preferably not used. This is because it is desired not to use drugs particularly for medical materials and medical materials.

  Cellulose sponges are generally produced as large sized blocks using a suitably sized mold. In the present invention, it may be freeze dried and commercialized or commercialized with the large dimensions taken out from the mold. On the other hand, freeze-dry in a large size state to produce a block-like product, and then cut appropriately to produce a small-sized block-like product or a thin sheet-like product. Is also good.

  Alternatively, after forming a cellulose sponge with a large size, it may be cut into a small size block or sheet, and then freeze-dried to form a product or product. . In the present invention, “cutting” is a concept including not only cutting but also slice cutting.

  In addition, after freeze-drying, press treatment at an appropriate pressure causes a slight dimensional variation in thickness, width, or length between individual products or products. May be compressed to suppress or align as much as possible.

  According to the present invention, since it is freeze-dried, even if the press treatment is performed, the cellulose sponge itself before the press is less contracted and less distorted. It can be done effectively and accurately.

  The press treatment can be performed either before or after the above-described cutting.

  The freeze-drying process can be performed by freeze-drying under the same conditions as in the case of food using a freeze-drying apparatus that has been conventionally used, typically used in the food industry. it can.

In the following, specific configurations and effects of the present invention will be described in accordance with examples.
In the following, the dimensions of the cellulose sponge are obtained by averaging the n number of samples as 10 sheets, and the actual dimensional measurement in each sample is obtained by taking the average value as n number 5.

A rectangular parallelepiped cellulose sponge was obtained by the following (a) to (j).
(A) Preparation of natural pulp 194 g of natural pulp (α cellulose 94% or more) was prepared.
(B) Immersion pulverization The natural pulp was put into an immersion machine, immersed in 18.8% caustic soda solution, and pulverized by a pulverizer.
(C) Aging Sulfur Furthermore, the pulp was aged by placing it at room temperature of 18 ° C. for 24 hours. Furthermore, 89 g of carbon disulfide was added to sulfidize the cellulose.
(D) Dissolution Aging Cotton fibers were mixed as reinforcing fibers so as to have a weight ratio of natural pulp: cotton fibers = 65: 35, and dissolved by adding 8% caustic soda solution and water.
(E) Mixing of mirabilite Furthermore, 10,800 g of mirabilite (sodium sulfate decahydrate) was prepared and mixed.
(F) Molding boiling The obtained mixed liquid was put into a mold having a rectangular parallelepiped shape (dimensions 110 mm × 180 mm × 395 mm), boiled, and solidified.
(G) Regeneration A rectangular parallelepiped cellulose regenerated material was obtained through the above steps.
(H) Washing with water Further washing with water and washing out of sodium sulfate (sodium sulfate decahydrate) gave a cellulose sponge structure.
(I) Post-treatment Further, as post-treatment, warm water washing, acid treatment, bleaching, and water washing were performed.
(J) Product From the above (a) to (j), a rectangular parallelepiped cellulose sponge having a moisture content of approximately 60% and a wet state was obtained as a product.

  The size and shape of this cellulose sponge body was a rectangular parallelepiped shape (height ratio: 61.7%) having a height of 95 mm, a width of 171 mm, and a length of 370 mm.

  From this rectangular parallelepiped shape, sliced parallel to the width direction, 10 sheets of wet cellulose sponge having a thickness (height) of 7.4 mm × width of 171 mm × length of 370 mm and a moisture content of approximately 60% are obtained. Obtained.

And this sheet | seat was used for the freeze-drying process demonstrated below.
That is, first, the wet cellulose sponge sheet was placed on a tray while keeping the horizontal state accurately, and placed in a freezer to perform quick freezing at minus 30 ° C.

  Thereafter, the frozen cellulose sponge sheet was placed on a tray in a drying furnace, and the inside of the drying furnace was evacuated by a vacuum pump to be in a vacuum state. In this state, steam was sent to the pipe under the tray to raise the temperature to about 80 ° C.

  The vacuum state was continuously maintained, and freeze drying was terminated when the temperature of the tray and the temperature of the frozen cellulose sponge sheet became substantially the same.

  The freeze-dried cellulose sponge sheet thus obtained has a thickness (height) of 6.7 mm (90.5% in terms of the above-mentioned slice sheet size ratio) × width of 163 mm (95.3% of the same) × length. It was a 363 mm (98.1%) thickness, and the overall shape was neither a distortion nor a twist, a good flatness, and a high quality sheet.

  From this result, the freeze-drying caused a contraction of about 10% in thickness, about 5% in width, and about 2% in the length direction.

  Adjust the thickness (height) of the final product (product) among multiple products (products) to improve the product quality and make the dimensions (especially thickness (height)) uniform as much as possible. For the purpose of illustration, press treatment in the thickness direction (thickness after pressing: about 0.7 mm) was performed to obtain a final cellulose sponge sheet product (product).

  The dimensions of the cellulose sponge sheet product (product) after the pressing were thickness (height) 0.7 mm × width 163 mm × length 362 mm.

  In order to evaluate the cellulose sponge sheet product (product) thus obtained, water was absorbed, and the water absorption was restored and dehydrated. The restored cellulose sponge sheet had a thickness (height) of 6.8 mm (91.9% in terms of the above-mentioned slice sheet size ratio) × width of 169 mm (98.8% of the same) × length of 370 mm (100 of the same). %)Met.

  As a result, it was confirmed that the thickness was recovered to about 90% by restoring the water absorption, and the width and length could be restored to the state of the wet cellulose sponge sheet.

  All of the 10 sheets were substantially the same, and it could be said that the product (product) was uniform.

Claims (8)

  A cellulose sponge, characterized in that the entire shape is freeze-dried and held to form a product.   A cellulose sponge characterized in that the whole shape is freeze-dried and held to be commercialized.   The cellulose sponge according to claim 1 or 2, which is used for medical equipment.   The cellulose sponge according to claim 1, 2 or 3, wherein the cellulose sponge comprises cellulose and cotton (cotton), flax, ramie, and pulp as reinforcing fibers alone or in combination thereof.   The cellulose sponge according to claim 1, 2, 3, or 4, wherein the cellulose sponge is formed into a product form or a product form without being provided with a chemical for preventing mold generation.   A cellulose sponge having a large size is formed, then cut into small sizes, and then freeze-dried to form a product or a product. Or the cellulose sponge of 5.   7. The cellulose sponge according to claim 1, wherein the cellulose sponge is formed into a product form or a product form after being freeze-dried and further pressed.   A cellulose sponge product characterized in that a cellulose sponge molded product produced in a production process in a wet state is subjected to a freeze-drying process while retaining the moisture in the wet state to form a product or a product. Or the manufacturing method of goods.