JP4831570B2 - Functional cellulose material having high functional particle content and method for producing the same - Google Patents

Description

  The present invention relates to a functional cellulose material having functions such as humidity control, VOC capture, deodorization, and antibacterial properties, and a method for producing the same.

It is known that cellulose microfibrils can be produced by grinding or beating cellulose-based fibers with a refiner, homogenizer, or the like (for example, Patent Document 1). A technique for manufacturing a sheet using cellulose microfibrils is also known. For example, a method for producing a high-strength microfibril sheet by making paper from a cellulose microfibril suspension (for example, Patent Document 2), a pulp sheet impregnated with warm water is kneaded to obtain a kneaded product, A method for producing a woody base material by adding water and mixing to obtain a molding preparation whose flowability is adjusted, putting the molding preparation into a mold, pressurizing and dehydrating, and drying (for example, patent document) 3) A method for producing an aliphatic polyester composition in which pulp is microfibrillated and dispersed in a resin component by melt-kneading pulp and aliphatic polyester in the presence of water (for example, Patent Document 4) It is. Microfibril sheets are light, strong, and highly biodegradable, so they can be used in a wide range of fields, including housings for home appliances such as personal computers and mobile phones, office equipment such as stationery, sports equipment, transportation equipment, and building materials. Is expected.
Japanese Patent Publication No. 50-38720 JP 2003-201695 A Japanese Patent No. 3522706 JP 2005-42283 A

  Sheets using these cellulose microfibrils have been developed from the viewpoints of strength, moldability, and biodegradability. However, as these commercialization approaches, the appearance of molded products having other functions has been desired. However, for the purpose of demonstrating the function, it is predicted that when a large amount of functional substance is added to cellulose microfibrils, the strength is predicted to be insufficient. When binders are used to compensate for the insufficient strength, the surface of the functional substance is Since it is covered with a binder, the function is reduced.

  Accordingly, an object of the present invention is to provide a highly functional cellulose material that is not impaired in strength as much as possible, a method for producing the same, and the like.

  The inventor mixes pulp and / or pretreated pulp with functional particles, kneads and pressurizes them to form the pulp, and / or the pretreated pulp incorporates functional particles. The inventors have found that a material that is microfibrillated, is light, has high strength, and contains a high proportion of functional particles can be obtained, thereby completing the present invention.

That is, the present invention provides the following production method.
Item 1. It includes kneading 3 to 50% by weight of pulp and / or pretreated pulp and 50 to 97% by weight of functional particles in the presence of water, pressurizing and kneading the kneaded product, and drying the molded product. A method for producing a functional cellulose material.
Item 2. Item 2. The method for producing a functional cellulose material according to Item 1, wherein the kneading, pressing, and molding are performed by a multiaxial kneading extruder.
Item 3. Item 2. The method for producing a functional cellulose material according to Item 1, wherein the average particle diameter of the functional particles is 2000 µm or less.
Item 4. The functional particles are at least one particle selected from the group consisting of wood powder, bark powder, natural zeolite, synthetic zeolite, artificial zeolite, titanium oxide, silica gel, activated carbon, crushed shell, diatomaceous earth, metal powder and tannin. Item 4. The method for producing a functional cellulose material according to any one of Items 1 to 3.
Item 5. The functional cellulose material manufactured by the method in any one of claim | item 1-4.
Item 6. A functional cellulose material containing 3 to 50% by weight of cellulose microfibrils and 50 to 97% by weight of functional particles and having a bending strength of 20 MPa or more.
Item 7. Item 7. The functional cellulose material according to Item 6, which contains 10 to 50% by weight of wood flour as functional particles and has a specific gravity of 0.6 to 1.3 g / cm ³ .
Item 8. Item 8. The functional cellulose material according to any one of Items 5 to 7, wherein the functional particles are at least one selected from the group consisting of wood powder, bark powder, and zeolite, and are for building interior materials.

  In the method for producing a functional cellulose material of the present invention, 3 to 50% by weight of pulp and / or pretreated pulp and 50 to 97% by weight of functional particles are kneaded in the presence of water, and the kneaded product is pressurized and dehydrated. , Including forming into a desired shape and drying, if necessary. Pulp and / or pretreated pulp is microfibrillated by kneading. Surprisingly, the microfibril has an action as an excellent binder capable of retaining a large amount of functional particles.

  In addition, the method of mixing and molding cellulose microfibril slurry and functional particles was also tried, but only cellulose microfibrils tend to condense and solidify (slurry tends to solidify), and dehydration is difficult to dehydrate. Conditions (temperature, pressure, etc.) tend to be severe.

  On the other hand, the production method of the present invention is advantageous in that the dispersion of the functional particles in the cellulose microfibril becomes more uniform and the dehydration is easier. And the molded product obtained by the production method of the present invention has a higher density and higher strength (particularly bending strength) than the molded product obtained by the method of molding by mixing cellulose microfibril slurry and functional particles, Functionality will be improved. In the present specification, the term “strength” means bending strength. The bending strength can be measured by the three-point support central concentrated load method described in JISK7171. The density can be measured by a bulk specific gravity measuring method described in JIS Z 8807.

  There is no restriction | limiting about the shape of the functional cellulose material of this invention, It can be set as a desired shape. Examples include, but are not limited to, fiber shapes, filament shapes, sheet shapes, rod shapes, column shapes, pipe shapes, column shapes, shapes of various containers, shapes of interior parts of transport equipment such as cars, etc. Can be molded.

Kneaded raw material In the present invention, the pulp used for kneading was recycled from chemical pulp such as kraft pulp, sulfite pulp, soda pulp, carbonated soda pulp, carbonated soda pulp, mechanical pulp, chemiground pulp, and waste paper Recycled pulp can be used. These pulps can be used alone or in combination of two or more. Examples of raw materials for these pulps include wood-based cellulose raw materials such as softwood chips, hardwood chips, and sawdust, and non-wood-based cellulose raw materials (for example, annual plants such as bagasse, kenaf, straw, reed, and esparto).

  Pretreated pulp is obtained by subjecting the above-mentioned pulp to a treatment advantageous for microfibrillation. When the pretreated pulp is used, the strength of the molded product obtained is higher than when a pulp that is not pretreated is used. Examples of the pretreatment include known refiner treatment, grinder treatment, medium stirring mill treatment, vibration mill treatment, and stone mill type treatment. In addition, although the pulp processed by refiner, grinder etc. may be classified as a semichemical pulp, the pretreated pulp in this invention includes this semichemical pulp. A preferred pretreatment is a refiner treatment. Further, among the refiner processes, a refiner process of 1 Pass to 10 Pass, preferably 5 Pass to 8 Pass is preferable. In the present invention, it can be used as a raw material for kneading whether it is only pulp, only pretreated pulp, or a combination of pulp and pretreated pulp.

  In the present specification, pulp and / or pretreated pulp may be referred to as pulps.

In the present invention, functional particles used for kneading include wood powder, bark powder, natural zeolite, synthetic zeolite, artificial zeolite, titanium oxide (preferably one having photocatalytic activity), silica gel, activated carbon, shell pulverized material, Particles such as diatomaceous earth, metal powder, and tannin are exemplified, and can be used singly or in combination of two or more. Preferred are wood powder, bark powder, natural zeolite, synthetic zeolite, artificial zeolite, tannin, and titanium oxide. By blending functional particles with pulp, the resulting material can be deodorized, deactivated oxygen, flame retardant, humidity control (moisture absorption / release), antibacterial, bactericidal, VOC (volatile organic compounds (formaldehyde, Functions such as toluene), xylene, ethylbenzene, etc.)) adsorbability can be imparted. In addition, it is also included in the present invention that these functional substances are combined with an appropriate carrier to form particles and are used for kneading. When wood powder is used as the functional particles, a functional material having a moisture absorption / release function is obtained, and when bark powder containing tannin is used, an active oxygen scavenging function, an antioxidant function, an antibacterial function, and an absorption / release function are obtained. A functional material having a moisture function is obtained. When zeolite is used, a functional material having a moisture absorption / release function, an adsorption function, and a flame retardant function is obtained, and when silica gel is used, a moisture absorption / release function is obtained. When activated carbon is used, a functional material having moisture absorption / release functions and adsorption functions is obtained, and when titanium oxide is used, oxidative decomposition functions, antibacterial functions, and deodorizing functions are obtained. A functional material having a sterilizing function is obtained when a crushed shell is used, and a functional material having a moisture absorbing / releasing function is obtained when diatomaceous earth is used.
The average particle size of the functional particles is not particularly limited, but is preferably 0.001 to 2000 μm, more preferably 0.01 to 1000 μm.

  In the present invention, the above pulps and functional particles are used as raw materials, and these are kneaded in the presence of water. The compounding quantity of pulp is 3 to 50 weight% of a raw material, Preferably it is 5 to 50 weight%, More preferably, it is 10 to 50 weight%. When the blending amount of the pulp is within the above range, a large amount of functional particles can be blended while maintaining the necessary strength. Moreover, the compounding quantity of a functional particle is 50 to 97 weight% of a raw material, Preferably it is 50 to 95 weight%, More preferably, it is 50 to 90 weight%. When the compounding amount of the functional particles is within the above range, the function of the functional particles is exhibited and the strength can be maintained.

  In addition to the above-described pulps and functional particles, additives can be added to the kneaded raw material within a range not impairing the effects of the present invention. Examples of additives include colorants, lubricants, stabilizers, and other various additives.

Kneading The raw materials are kneaded in the presence of water. By kneading, the pulps are microfibrillated while taking in functional particles. Water plays a role in swelling pulp and facilitating microfibrillation. The amount of water can be appropriately set in consideration of the means used for kneading, moldability and the like. For example, the amount of the solid content in the raw material is 20 to 60% by weight or the amount of water is 40 to 80% by weight, preferably 30 to 50% by weight. Examples of components that can be replaced with water or that can be added to water include ethylene glycol, butylene glycol, methyl alcohol, ethyl alcohol, and glycerin. These usage-amounts can be set according to the quantity of said water. When dehydration is necessary to adjust the amount of water, it can be dehydrated and adjusted by mechanical means such as a screw press, a disk press, a paper making machine, and a dewatering filter. Some of these dehydrating means also have a kneading function.

  In addition, operations such as pressurization, shearing, and compression are appropriately applied during kneading, and the pressure can be appropriately set according to the amount of pulp, the amount of functional particles, the amount of water, the shape of the molding, the kneading means, and the like. As a means for kneading, a Banbury mixer, screw press, kneader, multi-axis mixer (two-axis, three-axis, four-axis, etc.), disperser, etc. can be used. Alternatively, different means may be implemented in combination of two or more stages. A kneader equipped with means for subsequent molding can also be used. For example, a multi-screw kneading extruder such as a uniaxial kneading extruder and a biaxial kneading extruder. When a multiaxial kneading extruder is used, the dispersibility of the functional molecules is good, and the resulting material has a high density and bending strength, and a biaxial kneading extruder is particularly preferred.

  Here, the biaxial kneading extruder used is an apparatus used for mixing, plasticizing, and extruding general-purpose thermoplastic resins, and the rotation direction of the two screws may be either different direction or same direction rotation. . The engagement of the screw may be complete engagement or incomplete engagement. The screw length / screw diameter ratio may be 20 to 135. Specific examples of the biaxial kneading extruder include “KZW” manufactured by Technobel, “TEX” manufactured by Nippon Steel Works, “TEM” manufactured by Toshiba Machine, and “ZSK” manufactured by Coperion. The temperature at the time of kneading is not particularly limited, but is usually 10 to 80 ° C, preferably 20 to 60 ° C.

The kneaded and dehydrated kneaded product is molded. Prior to molding, the kneaded product may be dried. In molding, a molding method and a molding machine suitable for a desired shape may be appropriately selected. Extrusion molding and injection molding are particularly preferable, and extrusion molding is particularly preferable. As a means for extrusion molding, a known extrusion molding machine such as a screw extruder can be used. In the present invention, a multiaxial kneading extruder is preferred, and a biaxial kneading extruder is particularly preferred.

  Moreover, drying of a molded object is performed in order to remove the water | moisture content in a molded object. Usually, it is performed under a temperature condition of 80 to 110 ° C. Further, the air may be blown or depressurized during drying.

Functional cellulose material The functional cellulose material of the present invention is produced by the production method described above, and retains a large amount of functional particles with a small amount of cellulose microfibrils. For this reason, it has both high strength derived from cellulose microfibrils and high functionality derived from functional particles.

  Conventionally, it was thought that the strength was insufficient when the cellulose microfibrils were less than 50% by weight, but in the production method of the present invention, even when the cellulose microfibrils were 10% by weight (wood flour 90% by weight), the pressure was 28 MPa or more. A strong functional cellulose material was obtained.

In contrast to the material obtained by mixing and molding cellulose microfibril slurry and functional particles, the functional cellulose material of the present invention has a more uniform distribution of functional particles in cellulose microfibrils, a higher density, High strength (particularly bending strength). For example, the functional cellulose material of the present invention obtained by using a biaxial kneading extruder using 10% by weight of pretreated pulp and 90% by weight of wood flour as a raw material has a density of about 0.78 g / cm ³ and a bending strength of about 28 MPa. In contrast, the cellulose material obtained by kneading 10% by weight (solid content) of cellulose microfibrils and 90% by weight of wood flour has a density of about 0.5 g / cm ³ and a bending strength of about 1.9 MPa.

  The functional cellulose material of the present invention contains 3 to 50% by weight of cellulose microfibrils and 50 to 97% by weight of functional particles, and has a bending strength of 20 MPa or more.

  The functional cellulose material of the present invention has a function corresponding to the type of functional particles contained, and can be widely used in fields where the function can be utilized. For example, building interior materials, storage containers, interior materials for transport equipment such as automobiles, housings for home appliances such as personal computers and mobile phones, office equipment such as stationery, sports equipment, and packaging materials.

  According to the production method of the present invention, a functional cellulose material having high strength and high function can be obtained. Further, the functional cellulose material of the present invention has high functionality because of its high functional particle content, and has a sufficient strength although the cellulose microfibril content is small. In other words, the conflicting strength and functionality are compatible at a high level.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to an Example.

The setting of the apparatus used in the Example etc., material, a physical property, etc. are shown below.
<Wood flour>
“Cellulosin No. 100” (manufactured by Casino Co., Ltd.)
“Cellulosin No. 30” (Casino)

<Artificial zeolite>
“F _A Zeolite TypeCa” (Maeda Construction Co., Ltd.)
Cation conversion capacity (CEC) 150-400 cmol / kg
Specific surface area (SSA) 50-70 m ² / g
Median diameter 25μm
Particle size distribution 1-100μm

<Two-screw kneading extruder>
"KZW15TW" (manufactured by Technobel)
Screw diameter: 15mm
Screw length / screw diameter ratio: 30
Screw meshing type: Complete meshing type Screw rotation speed: 300rpm

<Stone mill grinder>
"Pure Fine Mill" (manufactured by Kurita Machinery Co., Ltd.)

<Refiner (conical refiner)>
“BEATFINER” (Satomi Manufacturing Co., Ltd.)

<Bending strength measuring machine (10Ton autograph)>
"AG-100kNG" (manufactured by Shimadzu Corporation)

Example 1: Biaxial kneading extrusion A molded product was produced from pulp and functional particles by biaxial kneading, and it was confirmed that the cellulose contained in the molded product was microfibrillated, and the specific gravity and bending strength were measured. did. First, toilet pulp was used as the pulp, and this was disaggregated at a ratio of water: pulp = 97 wt%: 3 wt%, and then subjected to a refiner treatment (5 Pass) with a conical refiner as a pretreatment. After this refiner-treated product (solid content concentration of 3 wt%) is mixed with wood flour (100 mesh) in a ratio of pulp (dry weight, the same in the following examples): wood flour = 50 wt%: 50 wt% Then, it was dehydrated with a centrifuge until the solid content became 30% by weight, and this was supplied to a twin-screw kneading extruder. An electron micrograph of a sample obtained by a biaxial kneading extruder (1 Pass) is shown in FIG.

What was kneaded in a mortar until it became uniform in a clay state while adding some water to this sample was put into a mold of a predetermined shape and dehydrated with a compression molding machine. The molded product was dried for 16 hours with a dryer at 105 ° C. to obtain a molded product (200 mm × 200 mm × plate thickness 8 mm). The obtained molded product was measured for specific gravity and bending strength (two samples). As a result, the specific gravity was 1.13 to 1.14 g / cm ³ (average value 1.14 g / cm ³ ), and the bending strength was 82.8 to 83.5 MPa (average value 83.10 MPa) (Table 1). . The specific gravity was a value obtained by dividing the weight of the molded sample by the volume. The bending strength was measured by processing a molded sample into a predetermined shape and measuring with a 10 Ton autograph.

Example 2: Biaxial kneading extrusion Pulp: Wood flour (100 mesh) = 10 wt%: 90 wt% A molded product was obtained in the same manner as in Example 1, and the specific gravity and bending strength of the molded product were evaluated. (The number of samples was three). As a result, the specific gravity was 0.77 to 0.78 g / cm ³ (average value 0.78 g / cm ³ ), and the bending strength was 26.6 to 29.5 MPa (average value 28.12 MPa) (Table 1).

Example 3: Biaxial kneading extrusion A molded product was obtained in the same manner as in Example 1 except that the functional particles were changed from wood flour to artificial zeolite, and pulp: artificial zeolite = 50 wt%: 50 wt%. The specific gravity and bending strength of the molded product were evaluated (two samples). As a result, the specific gravity was 1.42 to 1.47 g / cm ³ (average value 1.45 g / cm ³ ), and the bending strength was 60.2 to 65.6 MPa (average value 62.94 MPa) (Table 1).

Comparative Examples 1 to 6: Grinding and kneading treatment Toilet paper (pulp) was disaggregated at a ratio of water: pulp = 97% by weight: 3% by weight and then subjected to a refiner treatment without a refiner treatment (20 Pass). Then, microfibrillated cellulose was added, and functional particles (wood flour (30 mesh) and artificial zeolite) were added at a predetermined ratio and kneaded by hand. Molded products (solid content: 30% by weight) were obtained in the same manner as in Example 1, and the specific gravity and bending strength of these molded products were evaluated (two samples). The results are shown in Table 1 (specific gravity and bending strength are average values). In this example, the pulp was microfibrillated.

Comparative Examples 7 to 8: Non-kneading A refiner-treated product was obtained in the same manner as in Example 1, and wood flour (30 mesh) was added thereto at a predetermined ratio and mixed with a household mixer, but kneading was not performed. . Molded products were obtained from this mixture in the same manner as in Example 1, and the specific gravity and bending strength of these molded products were evaluated (the number of samples was 3 (50:50) and 2 (10:90)). The results are shown in Table 1 (specific gravity and bending strength are average values). In this example, the pulp is not microfibrillated. Moreover, although it was able to shape | mold in the sample of pulp: wood flour = 10: 90, since bending strength was very small, bending strength could not be measured.

Comparative Examples 9 to 10: Juicer Mixing A refiner-treated product was obtained in the same manner as in Example 1 (pulp solid content concentration 3 wt%), and wood flour (30 mesh) was added to this at a predetermined ratio, and the cooking juicer was used approximately. Stir and mix for 5 minutes. Molded products were obtained from the obtained mixture in the same manner as in Example 1, and the specific gravity and bending strength of these molded products were evaluated (the number of samples was 3). The results are shown in Table 1 (specific gravity and bending strength are average values). In this example, the pulp is not microfibrillated.

  As shown in Table 1, the molded product that had undergone the biaxial kneading extrusion treatment had a very high strength of 28 MPa or more in the bending strength test even though the pulp content was very small. For this reason, if a pulp compounding quantity can be decreased, many functional particles can be mix | blended, and it can be set as the functional material which has the high function derived from high intensity | strength and functional particles. On the other hand, in the comparative example, since the strength is 7.02 MPa or less, when the same amount of functional particles as in the example is blended, only a material having low strength can be obtained. When the content is increased, the functional particles are reduced, and only materials having a relatively lowered function can be obtained.

Example 4:
Kraft pulp was used as the pulp, and this was disaggregated at a ratio of water: pulp = 97 wt%: 3 wt%, and then subjected to a refiner treatment (8 Pass) with a disc refiner as a pretreatment. Wood refinement (100 mesh) is added to this refiner-treated product (solid content concentration 3 wt%) (pulp: wood flour = 10: 90) and dehydrated to a solid content of 30% by weight with a centrifuge. It supplied to the shaft kneading extruder. A sample obtained by a biaxial kneading extruder (1 Pass) was obtained in the same manner as in Example 1, and the specific gravity and bending strength of the molded product were evaluated (the number of samples was 2). As a result, the specific gravity was 0.68 to 0.71 g / cm ³ (average value 0.70 g / cm ³ ), and the bending strength was 20.9 to 23.6 MPa (average value 22.2 MPa).

Example 5:
A molded product was obtained in the same manner as in Example 4 except that the disc refiner treatment was not performed, and the specific gravity and bending strength of the molded product were evaluated (two samples). As a result, the specific gravity was 0.64 to 0.65 g / cm ³ (average value 0.65 g / cm ³ ), and the bending strength was 11.7 to 13.4 MPa (average value 12.6 MPa). The disc refiner treatment (Example 4) was advantageous in terms of bending strength.

Example 6:
Kraft pulp was used as the pulp, and this was disaggregated at a ratio of water: pulp = 97 wt%: 3 wt%, and then subjected to a refiner treatment (8 Pass) with a disc refiner as a pretreatment. Artificial zeolite is added to this refiner-treated product (solid content concentration: 3 wt%) (pulp: artificial zeolite = 50: 50) and dehydrated with a centrifuge until the solid content reaches 30% by weight. Supplied to. A sample obtained by a biaxial kneading extruder (1 Pass) was obtained in the same manner as in Example 1, and the specific gravity and bending strength of the molded product were evaluated (the number of samples was 3). As a result, the specific gravity was 1.39 to 1.42 g / cm ³ (average value 1.41 g / cm ³ ), and the bending strength was 53.1 to 75.1 MPa (average value 65.4 MPa).

Example 7:
A molded product was obtained in the same manner as in Example 6 except that the disc refiner treatment was not performed, and the specific gravity and bending strength of the molded product were evaluated (three samples). As a result, the specific gravity was 1.42 to 1.47 g / cm ³ (average value 1.44 g / cm ³ ), and the bending strength was 49.0 to 65.6 MPa (average value 58.3 MPa). The disc refiner treatment (Example 6) was advantageous in terms of bending strength.

  The present invention is useful in the field of functional materials containing cellulose microfibrils having both bending strength and high functionality.

The scanning electron micrograph (5000 times) of the functional cellulose material of this invention manufactured in Example 1 is shown.

Claims (3)

It includes kneading 3 to 50% by weight of pulp and / or pretreated pulp and 50 to 97% by weight of functional particles in the presence of water, pressurizing and kneading the kneaded product, and drying the molded product. A method for producing a functional cellulose material ,
A method for producing a functional cellulose material, wherein the kneading, pressurizing and molding are performed using a biaxial kneading extruder . The method for producing a functional cellulose material according to claim 1, wherein the average particle diameter of the functional particles is 2000 μm or less. The functional particles are at least one particle selected from the group consisting of wood powder, bark powder, natural zeolite, synthetic zeolite, artificial zeolite, titanium oxide, silica gel, activated carbon, crushed shell, diatomaceous earth, metal powder and tannin. The method for producing a functional cellulose material according to claim 1 or 2 .

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