JPH03152130A - Powdery or granular fine fiber material and production thereof - Google Patents

Abstract

PURPOSE:To obtain the subject material, excellent in handleability and capable of disaggregating and rehydrating by stirring in a short time in placing thereof in water substantially without reblocking by providing a powdery or granular material using microfibrillated fiber in a state wetted with a medium. CONSTITUTION:The objective material obtained by dispersing a fibrous substance such as cellulose, chitin, chitosan or collagen in a medium (e.g. water), treating the resultant dispersion in a high-pressure homogenizer, microfibrillating the aforementioned fibrous substance and having the thickness of the fibrillated fiber having D<1mum and the formula 500<L/D<100000 (D is the fineness of the microfibrillated fiber; L is the length), providing a slurry in 0.5-10wt.% concentration, then subjecting the aforementioned slurry to dehydration treatment such as draining with a filter press, etc., to afford a caky solid in 10-60wt.% solid concentration and pulverizing the resultant caky solid into a powdery or granular material having 3-200 mesh particle diameter under wet conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a microfiber material that can be handled as powder or granules and a method for producing the same. The microfiber material of the present invention has a wide range of applications, and is useful, for example, in the food industry, cosmetics industry, ceramic industry, paper industry, textile industry, etc.

[Prior art and problems to be solved by the invention] As an example of a microfiber material made of cellulose,
There is a microfibrous cellulose described in Japanese Patent No. 19921. In this prior art, the microfibrous material is obtained as an aqueous suspension containing less than 10% by weight of cellulose, usually less than 5% by weight, and must normally be used in that form. However, such highly viscous suspensions with large amounts of dispersion medium are disadvantageous in transportation, storage, and handling during use, and also introduce unnecessary or undesirable dispersion medium into the use system in excess of the allowable amount. In some cases, the aqueous suspension described in Japanese Patent Publication No. 60-19921 could not be said to be satisfactory.

Furthermore, as an example of a fine fiber material made of chitin instead of cellulose, there is one described in JP-A-61-149237, but the fine particle suspension described in this publication is also basically based on the above-mentioned JP-A-60-19921. It has the same problems as the suspension described in the publication.

Another example of a microfibrous material made of cellulose is microfibrillated cellulose described in Japanese Patent Application Laid-Open No. 189141/1983. In this prior art, the microfibrous material microfifurylated cellulose is obtained as a dry product and is usually used in that form. However, this microfibrous material consisting of dried microfifurylated cellulose is usually prepared with a large amount of additives other than cellulose, i.e., compounds that substantially prevent hydrogen bonding between the cellulose fibers, such as sycoclose, glycerin, polyethylene glycol, etc. , starch, and other additives, which limit the uses of microfifurylated cellulose. For example, if the additive is saccharide, there are some fields such as cement where the strength is not developed due to the presence of bran during the hardening reaction, so the disadvantage is that it can only be used in extremely limited fields such as food additives. However, it has the disadvantage that it can only be used for limited purposes. On the other hand, if it does not contain any additives other than cellulose, it is difficult to commercialize it because the functional protection of the fine fibers is not sufficient in the dry state and the original performance is lost. On the other hand, in the conventional technology of dispersing with a large amount of water, the dispersion liquid is 3.000 cp to 50.000 cp.
Due to its high viscosity, it cannot be handled as a normal liquid and requires special high viscosity fluid equipment. In addition, for water suspensions that contain a large amount of water, if the amount of water itself used in the manufacturing process is limited, such as when added to cement by extrusion molding, the amount added to the cement, etc. may be kept low. However, it had the disadvantage of not being able to express sufficient functionality.

Furthermore, a microfiber material made of dried microfifurylated chitin or chitosan instead of dried microfifurylated cellulose is described in JP-A-61-159430, but this prior art also basically There are the same problems as those described in the above-mentioned Japanese Patent Application Laid-Open No. 59-189141.

The present inventors have made a thorough study of the problems that conventional microfiber materials have, and found that they can be handled substantially as powder or granules, so they can be used with ordinary powder handling machines (e.g., belt conveyors, rotary valves, etc.). As a result of our research, we have developed a product that has a shape that is suitable for use in microfibers, scale hoppers, and other charging equipment, maintains the original functions of fine fibers, and has properties that meet the demands of the field of use. This led to an invention.

[Means to solve the problem]

Microfifurylated fibers, such as microfifurylated cellulose or microfibrillated chitin or chitosan, form stable, highly viscous suspensions in water or other polar solvents, but when dried, they As such, its essential properties of dispersibility, hydration and viscosity are lost or substantially reduced. However, the present inventors removed the liquid from a suspension obtained by suspending microfibrillated fibers in a medium by using a filter press or centrifugation to obtain a solid content of 10 to 60.
% cake-like material, and the powder obtained by crushing this is a fine fiber material that can be handled as a powder or granule without substantially reblocking, and is disclosed in JP-A-59-
The present invention was based on the discovery that the properties such as dispersibility, hydration, and viscosity of microfifurylated fibers do not substantially change even if additives such as polyhydroxy compounds as described in Publication No. 189141 are not blended. This led to an invention.

That is, the present invention provides a microfibrous material which is made of microfibrillated fibers wetted with a medium and which can be handled as a powder or granule material without substantially reblocking, and which, when redispersed in a medium, produces a powder or granule material. The present invention relates to a granular microfiber material having a viscosity of at least 50% of the viscosity of the same concentration of microfibrillated fibers dispersed in a medium before microfibrillation. The above-mentioned powder-like material is produced by deliquifying a suspension of fifurlated fibers in a medium, and crushing the obtained cake-like material to obtain a powder-like material. A method of manufacturing a microfiber material is provided.

The microfibrous material of the present invention contains an amount of medium necessary to maintain redispersibility in the medium as shown by the fact that the viscosity does not substantially change or decrease, and its form is such that it can be handled as a powder or granule. It is characterized by being in the form of a powder or granule that does not substantially reblock, and such a fine fiber material in the form of a powder or granule has not been known so far.

Next, the outline of the manufacturing process of the microfiber material according to the present invention will be explained.

A raw material fibrous material (eg, cellulose) is dispersed in a medium (eg, water) and treated with a high-pressure homogenizer to obtain a microfifurylated suspension of the fibrous material (first step). Next, this suspension is dehydrated (for example, by filter press dehydration) to form a hard cake (second step). This cake-like material is then pulverized to a degree that is convenient to handle, so that it forms blocks that are not mutually adhesive, even when wet with a liquid medium, and that the packaged materials can be stacked on top of each other. The microfiber material is made into a fine fiber material that can be handled as a powder or granular material without causing any damage (third step).

Hereinafter, the structure and operation of the present invention will be explained in detail in order.

(First step) There is no need to specifically limit the fibrous material as a raw material, but
Cellulose is practically the most commonly used material due to its economic efficiency and wide range of applications. The raw materials for cellulose include not only pulp and linters but also those derived from other plants, animals, and microorganisms.

Fibrous substances other than cellulose may be selected depending on their features, functions, and uses; chitin, chitosan, leather, etc. are particularly useful, but soybean fiber, wool, silk, etc. may also be useful. . It is also possible to use synthetic fibers, such as aramid fibers.

Water is usually the most suitable medium for reasons of economy, ease of handling, and versatility. Organic solvents such as methanol, ethanol, and mixed media of these organic solvents and water may be useful (such as when obtaining microfiber materials).

The method of obtaining a suspension of microfibrillated fibers by treatment with a high-pressure homogenizer is a conventional technique (Japanese Patent Publication No. 60-1992).
1, Japanese Unexamined Patent Publication No. 61-149237). That is, a slurry of raw material fibrous material having a concentration of 0.5 to 10% by weight is prepared, and when the slurry is passed through a small-diameter orifice, a small amount (both 200 k
The shearing and cutting action is achieved by applying a high velocity with a pressure difference of g/cm 2 and then colliding with the wall near the orifice exit and rapidly decelerating it. Then, by repeating the process of passing through this orifice to perform a shearing and cutting action until the fibrous material is microfifurilized and becomes a substantially stable g, m liquid, the desired microfifurils are produced. A stable suspension of composite fibers is obtained.

In such microfibrillated fibers, a large number of fine fibers are observed over the entire length according to an electron micrograph. The fineness does not necessarily have to be perfect, and slightly thicker and bundled fibers may be mixed in.

Microfibrillated fiber size
The length and length (hereinafter abbreviated as ri) are subject to restrictions depending on the intended use of the solidified microfiber material, but as a rough guide, if expressed numerically, D<1.
μm1 preferably 0.02 to 0.3 μm, 500<
L/D<100.600.

(Second Step) As a method for removing liquid from the suspension, a physical solid-liquid separation method, such as filter press deliquid or centrifugal deliquid, can be applied.

The degree of liquid removal is arbitrary as long as it satisfies the properties and functions of the final product, but taking into account the cost of liquid removal and the cost of the next process, the solid content concentration should be about 10 to 60%, preferably 20 to 60%.
Approximately 50% is desirable. Usually, the deliquate is obtained as a hard cake-like solid.

(Third Step) The granular material of the present invention is obtained by pulverizing a cake-like solid moistened with a medium while maintaining that state.

To explain specifically by way of example, the centrifugal dehydrated product or the press dehydrated product obtained in the form of a cake is not completely dried, but is pulverized under such pulverizing conditions that it is kept moist with a liquid medium. The obtained material can be handled as a powder or granules, and can also be redisaggregated and rehydrated.

Normally, pulverization generates heat and tends to partially dry out, causing the microfiber material to lose its surface characteristics. It was not previously known that there could be a material that was compatible with both.

The method and degree of pulverization of the deliquid product should be selected depending on the intended use, but the pulverizing equipment may be of a commercially available type and does not require any special equipment. The size of the pulverized material is preferably such that it can be handled by a commercially available powder handling machine, and it is desirable that the size of the pulverized product be such that it can pass through 3 meshes and not pass through 200 meshes, preferably pass through 5 meshes and not pass through 100 meshes. A material that does not pass through 3 meshes is not only inconvenient to handle, but also requires a large amount of energy for stirring and homogenizing when redispersing and resuspending in the system used. On the other hand, fine particles that pass through 200 meshes pose no particular problem in practice, but making them finer than necessary not only requires a special grinder but also increases the grinding cost, which is disadvantageous.

The following processing may be performed in this third step. In other words, by humidifying the surface of the fine fiber aggregate by blowing steam or spraying water during the crushing process, the redispersibility of the surface of the fine fiber aggregate can be further improved, or conversely, by crushing in a large amount of dry air or heated air. This process involves keratinizing the surface of the fine fiber aggregate, suppressing dispersion during use, and creating a material that does not thicken.

(Fourth Step) Among the processing treatments described above, a treatment for keratinizing the surface of the fine fiber aggregate can also be carried out as the fourth step. That is, the surface of the easily dispersible fine fibers obtained in the third step can be keratinized by blowing heated and dry air, thereby suppressing dispersion during use and producing a material that does not thicken.

The microfiber material obtained by blowing heated dry air to keratinize the surface and preventing redispersion/resuspension in the usage system is sterilized at the same time, and is relatively effective. It is suitable for food applications where it is used in high concentrations.

〔Effect of the invention〕

The powdery microfiber material of the present invention has excellent handling properties during transportation, storage, and use, and also has excellent disintegration properties in water. shows stable performance. Furthermore, since it does not substantially contain any solid content other than fiber materials, there are no disadvantages associated with conventional additives such as sugars or starch.

〔Example〕

EXAMPLES The present invention will be described below with reference to Examples, but it goes without saying that the present invention is not limited to these Examples.

Example 1 [Microfifurylated chitin] Using purified chitin as a raw material, a 3.5% aqueous suspension of chitin that has been pretreated so that it can pass through the nozzle of the device is prepared at room temperature (25°C).
) with a high-pressure homogenizer (Gaulin 15M-8T^
) and treated 10 times at a pressure of 500 kg/cm"G. The resulting fine fiber material suspension was adjusted to a concentration of 2%, and the viscosity was measured using a viscometer (model BL, manufactured by Tokyo Keiki).
It was 1.650 cpS (25°C).

Next, this suspension is subjected to deliquification treatment using a filter press (manufactured by Kurita Kikai) under the conditions of a pressure cuff of 0 kg/cm2G and a time of 20 minutes. The solid content of the resulting cake was 25%. This cake is crushed in a pulverizer (tabletop high-speed rotating mixer, manufactured by Kodaira Seisaku Shin) at a low speed of 30 seconds and a high speed of 1 minute. When the particle size of the obtained powder and granular material was measured using a test sieve,
97% of the samples passed through 6 meshes and did not pass through 48 meshes.

This granular material was re-disaggregated using Homo Disper (manufactured by Tokushu Kika Kogyo) at a concentration of 2% and a rotational speed of 5.00 rpm for 10 minutes, and the viscosity was measured using a viscometer: 1,570c
ps (25°C).

Example 2 (Microfifurylated cellulose (linter)) Using purified link (Barakai HVE) as a raw material, it was pretreated in the same manner as in Example 1, and then processed using a high-pressure homogenizer at a concentration of 2% and a pressure of 500 kg/cm2G. The viscosity of the resulting microfibrous material suspension is 1.950 cp.
s (25°C). As in Example 1, this suspension was subjected to deliquification treatment using a filter press under the conditions of a pressure of 4 kg/cm''G and a time of 1 minute.The solid content of the resulting cake was 25%.

This cake is crushed using a crusher. When the particle size of the obtained granular material was measured in the same manner as in Example 1, it was found that 81% of the particles passed through 6 meshes and did not pass through 48 meshes. Similarly to Example 1, this granular material was re-disaggregated at a concentration of 2% and its viscosity was measured to be 2.050 cps (25°C).

Example-3 [Microfifurylated cellulose (wood pulp)
] Wood bulbs (Renia, Alphania F) were used as raw materials, and after being pretreated in the same manner as in Example-1, the mixture was heated to 12% using a high-pressure homogenizer at a concentration of 4% and a pressure of 500 kg/cm"G.
Process times. The resulting microfibrous material suspension had a viscosity of 3.500 cps (25° C.) at a concentration of 2%. This suspension was applied to a centrifuge (Tanabe Tekko rupture), and the centrifugal effect G
= 670, and the dewatering process is performed for 3 hours. The solid content of the resulting cake was 25%. This cake was pulverized with a pulverizer and the particle size distribution was measured, and it was found that 99% of the particles passed through 6 meshes and did not pass through 48 meshes. The obtained granular material was re-disaggregated at a concentration of 2% in the same manner as in Example 1, and the viscosity was measured.
．． It was 400 cps (25°C).

Example 4 [Microfifurillated leather] Shaving waste (50% moisture content) generated from the manufacturing process of chrome-rubbed leather products is processed using a centrifugal pulverizer (newly manufactured by Nippon Seiki Seisakusho).
Pre-grind with. The wire mesh used has a hole diameter of 1 mm. The pulverized skin powder is applied to a high-pressure homogenizer and treated 20 times at a concentration of 2% and a pressure of 500 kg/cm'G. The viscosity of the resulting microfibrous material suspension was 1.200 cps (25
℃). This suspension is deliquified in advance using a centrifugal separator, and then squeezed and deliquified using a press. The solid content of the resulting cake was 25%. This deliquified cake was pulverized with a pulverizer and the particle size distribution was measured, and it was found that 90% of the particles passed through 5 meshes and did not pass through 80 meshes. The obtained granular material was re-disaggregated at a concentration of 2% in the same manner as in Example 1, and the viscosity was measured to be 700 cps (25°C).

Example-5 [Microfifurylated aramid fiber] Kevlar (
Kevlar (trade name of aramid fiber manufactured by Du Pant, USA) was used as a raw material, pretreated in the same manner as in Example 1, and then heated to a concentration of 2% and a pressure of 500 using a high-pressure homogenizer.
kg/crn" G 10 times. The viscosity of the obtained microfiber suspension was 2.200 cps at a concentration of 1%. This suspension was centrifuged and the centrifugal effect G = 670
, the liquid removal process is performed for 60 minutes. The solid content of the resulting cake was 25%. Grind this cake with a grinder,
When the particle size distribution was measured, 95% of the particles passed through 5 meshes and did not pass through 80 meshes. In addition, the obtained powder and granule material had a concentration of 1
%, and the viscosity was measured, it was 2.500CpS.
(25°C).

Claims (1)

[Scope of Claims] 1. A fine fiber material in the form of a powder or granule, which is made of microfibrillated fibers moistened with a medium and can be handled as a powder or granule without substantially reblocking. 2. The microfibrous material according to claim 1, wherein some or all of the microfibrillated fibers consist of a natural or synthetic fibrous material. 3. The microfibrous material according to claim 1, wherein part or all of the microfibrillated fibers consist of chitin and/or chitosan. 4. The microfibrous material according to claim 1, wherein part or all of the microfibrillated fibers are made of cellulose. 5. The microfibrous material according to claim 1, wherein part or all of the microfibrillated fibers are made of leather fibers (collagen). 6. Claim 1, characterized in that a suspension in which microfifurylated fibers are suspended in a medium is deliquified, and the resulting cake-like material is crushed under humid conditions to form a granular material. A method for producing the powdery microfiber material described above. 7. The method for producing a microfibrous material according to claim 6, wherein part or all of the microfibrillated fibers are made of a natural or synthetic fibrous material. 8. The method for producing a microfibrous material according to claim 6, wherein part or all of the microfibrillated fibers are composed of chitin and/or chitosan. 9. The method for producing a microfibrous material according to claim 6, wherein part or all of the microfibrillated fibers are made of cellulose. 10. The method for producing a microfiber material according to claim 6, wherein part or all of the microfibrillated fibers are made of leather fibers (collagen). 11. The method for producing a microfiber material according to claim 6, wherein the dewatering treatment is filter press dewatering or centrifugal dewatering. 12. The method for producing a fine fiber material according to claim 6, wherein the cake-like substance has a solid content concentration of 10 to 60%. 13. The method for producing a fine fiber material according to claim 6, wherein the size of the powder or granule material is 3 mesh to 200 mesh.