Binder and Method for Manufacturing a Formed Body

Abstract

The present invention provides an adhesive and a method for manufacturing a formed body, which can manufacture a formed body with sufficient strength when used as an adhesive for binding fibers or the like to form a formed body. The adhesive (C10) is an adhesive containing binder material particles (C2) and inorganic oxide particles (C3). The binder material particles (C2) are capable of binding fibers to each other by being supplied with moisture. The adhesive (C10) contains composite particles (C1) in which the binder material particles (C2) and the inorganic oxide particles (C3) are integrated. The inorganic oxide particles (C3) contain carbon, and the content of the carbon is 2% by mass or more relative to the mass of the inorganic oxide particles (C3).

Description

Technical Field

[0001] The present invention relates to an adhesive and a method for manufacturing a formed body. Background Art

[0002] As a method for manufacturing a formed body such as a cushioning material by recycling waste paper without using a large amount of water as in the papermaking method, a method for manufacturing a formed body of a formed body has been proposed in which water in a mist form is added to a substance obtained by defibrating waste paper into a cotton-like substance and further a powdery or granular adhesive is added (for example, refer to Patent Document 1). Such a method for manufacturing a formed body has the following advantages: compared with the papermaking method, a formed body can be manufactured using only a small amount of water, and thus, energy and time spent on dehydration, drying, etc. can be saved.

[0003] However, in the above-described method for manufacturing a formed body, there is a case where even if only a powdery adhesive is mixed in the fibers, it is difficult to uniformly distribute the adhesive in the formed body, and as a result, it is difficult to sufficiently ensure the strength of the obtained formed body. In particular, in the case of manufacturing a thin sheet-like formed body such as recycled paper as a formed body, there is a problem that when there is a region where the amount of the adhesive is small, the formed body breaks starting from this part, thereby reducing the strength of the sheet.

[0004] Patent Document 1: Japanese Patent Laid-Open No. 5-246465 Summary of the Invention

[0005] The adhesive is an adhesive containing binder material particles and inorganic oxide particles, the binder material particles contain a binder material that binds fibers to each other by being given moisture, the adhesive contains composite particles in which the binder material particles and the inorganic oxide particles are integrated, the inorganic oxide particles contain carbon, and the content of the carbon is 2% by mass or more relative to the mass of the inorganic oxide particles.

[0006] The method for manufacturing a formed body includes: a stacking step of stacking a mixture containing fibers and the above-described adhesive; a humidifying step of giving moisture to the stacked mixture; and a forming step of obtaining a formed body by heating and pressurizing the mixture to which moisture has been given. Brief Description of the Drawings

[0007] Figure 1 It is a schematic view of the adhesive according to the embodiment.

[0008] Figure 2 It is a schematic side view showing the structure of a manufacturing apparatus suitable for implementing the method for manufacturing a formed body. Detailed Description

[0009] 1. Binder

[0010] As shown in Figure 1 , the binder C10 is a binder C10 comprising binder material particles C2 and inorganic oxide particles C3. The binder material particles C2 comprise a binder material that causes the fibers to bond to each other upon being given moisture. The binder C10 comprises composite particles C1 in which the binder material particles C2 and the inorganic oxide particles C3 are integrated. The inorganic oxide particles C3 contain carbon, and the content of carbon is 2% or more by mass relative to the mass of the inorganic oxide particles C3.

[0011] Thus, when using the binder C10 to bond fibers to each other to form a shaped body, a shaped body having sufficient strength can be obtained. Specifically, by making the inorganic oxide particles C3 contained in the composite particles C1 contain 2% or more by mass of carbon relative to the mass of the inorganic oxide particles C3, the surface free energy of the inorganic oxide particles C3 is effectively reduced. As a result, the binder C10 can be better fused to the surface of the fibers. Thus, the finally obtained shaped body becomes a shaped body with more excellent adhesion between the fibers and the binder C10, and thus the strength of the shaped body can be made excellent. Moreover, since the binder C10 of the present invention has excellent dispersibility, it is possible to effectively suppress the unintentional aggregation of the binder C10 with each other during the storage of the binder C10 or the conveyance of the binder C10 during the manufacturing process of the shaped body.

[0012] In addition, in the present invention, the state in which at least a part of the inorganic oxide particles C3 is attached to the surface of the binder material particles C2 or at least a part of the inorganic oxide particles C3 is contained inside the binder material particles C2 to form the composite particles C1 is referred to as "composite particles C1 in which the binder material particles C2 and the inorganic oxide particles C3 are integrated". That is, the case where the binder C10 contains binder material particles C2 and inorganic oxide particles C3 that do not form composite particles C1 is not excluded.

[0013] In the illustrated structure, in the composite particles C1 contained in the binder C10, the inorganic oxide particles C3 are attached to the surface of the binder material particles C2.

[0014] Thus, a repulsive force acts between the inorganic oxide particles C3, making it difficult for the binder material particles C2 to aggregate with each other. In addition, the arrangement of the inorganic oxide particles C3 can be confirmed by, for example, various electron microscopes.

[0015] 1.1. Composite particles

[0016] The composite particle C1 included in the binder C10 may also be a composite particle in which a single inorganic oxide particle C3 is attached to the surface of a single binder particle C2. However, preferably, the binder C10 contains particles in which a plurality of inorganic oxide particles C3 are attached to the surface of a single binder particle C2 as the composite particle C1.

[0017] As a result, a repulsive force effectively acts between the inorganic oxide particles C3, making it more difficult for the binder particles C2 to agglomerate.

[0018] The average particle diameter of the composite particle C1 is preferably 1.0 μm or more and 100.0 μm or less, more preferably 2.0 μm or more and 70.0 μm or less, and still more preferably 3.0 μm or more and 50.0 μm or less. Thus, it is easy to uniformly distribute the composite particle C1 with respect to the formed body.

[0019] In addition, in this specification, unless otherwise specified, the average particle diameter refers to the median diameter (D50 value at a cumulative frequency of 50%). The average particle diameter can be obtained, for example, by measurement using Microtrac UPA (manufactured by Nikkiso Co., Ltd.).

[0020] 1.1.1. Binder particles

[0021] The binder particle C2 is a particle containing a binder that causes fibers to bind to each other by being given moisture.

[0022] Examples of the binder constituting the binder particle C2 include components derived from natural products such as starch, dextrin, glycogen, amylose, hyaluronic acid, kudzu, konjac, potato starch, etherified starch, esterified starch, natural gum pastes (etherified tamarind gum, etherified locust bean gum, etherified guar gum, gum arabic), fiber-responsive pastes (etherified carboxymethyl cellulose, hydroxyethyl cellulose), seaweeds (sodium alginate, agar), animal proteins (collagen, gelatin, hydrolyzed collagen, sericin), etc., polyvinyl alcohol, polyacrylic acid, polyacrylamide, etc. One or a combination of two or more substances selected from the above materials can be used, but preferably, components derived from natural products are used, and more preferably, starch is used.

[0023] By using components derived from natural products as the binder, the use of petroleum-derived materials is suppressed, and CO2 emissions are reduced. In addition, the biodegradability of materials derived from natural products is excellent.

[0024] In particular, starch is a material that undergoes gelatinization by heating after being given moisture, thereby appropriately exerting its binding force. That is, it is a binding material that appropriately exerts the binding force that causes fibers to bind to each other when moisture is given. In addition, starch exerts a binding force through non-covalent bonds such as hydrogen bonds between fibers, especially fibers composed of materials having functional groups such as hydroxyl groups like cellulose fibers. And because of its excellent binding force with fibers and excellent covering property with respect to fibers, it can make the strength of the molded body manufactured using binder C10 and the like more excellent.

[0025] Preferably, the binding material contains starch having a weight-average molecular weight of 50,000 or more and 400,000 or less. The weight-average molecular weight of the starch is more preferably 70,000 or more and 300,000 or less, and even more preferably 80,000 or more and 200,000 or less.

[0026] Thereby, the water absorption efficiency of binder C10 can be made more excellent, and a molded body having sufficient strength can be further manufactured. More specifically, even when a small amount of water is given, the gelatinization of starch caused by heating can proceed appropriately, and the productivity of the molded body using binder C10 is excellent. In addition, the strength of the manufactured molded body can be made excellent. Moreover, starch having a weight-average molecular weight within the above range is not likely to cause unintended modification due to the addition of moisture.

[0027] In addition, the weight-average molecular weight of starch can be determined by measurement performed by gel permeation chromatography. The weight-average molecular weight shown in the examples described later is also a value determined by measurement performed by gel permeation chromatography.

[0028] Starch having a weight-average molecular weight controlled to be within a predetermined range can be appropriately obtained in the following manner. For example, after suspending natural starch in water, sulfuric acid, hydrochloric acid, or sodium hypochlorite is allowed to act under conditions where the starch does not gelatinize, thereby obtaining starch having a weight-average molecular weight controlled to be within a predetermined range. In addition, for example, when natural starch is directly diluted with water or a very small amount of volatile acid such as hydrochloric acid is added and thoroughly mixed and ripened, and then dried at a low temperature, starch having a weight-average molecular weight controlled to be within a predetermined range can be obtained by heating at 120 to 180 °C. In addition, for example, by performing a treatment of hydrolyzing the paste obtained by heating natural starch and water together with an acid or an enzyme, starch having a weight-average molecular weight controlled to be within a predetermined range can be appropriately obtained.

[0029] Starch is a high-molecular material in which multiple α-glucose molecules are polymerized through glycosidic bonds. Starch contains at least one of amylose and amylopectin.

[0030] In addition to the binder, the binder material particles C2 may contain components other than the binder, that is, components that do not exhibit a binding force for binding fibers to each other even when moisture is imparted. Examples of such components include fibrous materials, pigments, dyes, color materials such as toners, and the like.

[0031] The content rate of the binder in the binder material particles C2 is preferably 80% or more by mass, more preferably 90% or more by mass, and further preferably 95% or more by mass.

[0032] The average particle diameter of the binder material particles C2 is preferably 1.0 μm or more and 50.0 μm or less, more preferably 3.0 μm or more and 30.0 μm or less, and further preferably 5.0 μm or more and 15.0 μm or less.

[0033] Thus, in the case of manufacturing a shaped body by binding fibers using the binder C10, the fibers and the binder C10 can be more uniformly mixed in the step of mixing the fibers and the binder C10. In addition, when moisture is imparted to the mixture of the fibers and the binder C10, the absorption of moisture proceeds more smoothly, and the strength and reliability of the finally obtained shaped body can be made more excellent. In particular, when the particle diameter of the binder material particles C2 is such a small particle diameter, the surface area per unit mass of the binder material particles C2 becomes larger, and the water absorption efficiency achieved by the binder is more excellent. As a result, even when the amount of moisture imparted is small, a shaped body having sufficient strength can be manufactured.

[0034] In addition, when the binder material particles C2 having a relatively small average particle diameter do not coexist with the inorganic oxide particles C3 in the binder C10 in such a manner, aggregation of the binder material particles C2 occurs frequently. However, in the present invention, by providing the composite particles C1 in which the binder material particles C2 and the inorganic oxide particles C3 are integrated, aggregation of the binder material particles C2 can be effectively prevented. That is, since the average particle diameter of the binder material particles C2 is within the above range, even when aggregation of the binder material particles C2 is likely to occur, aggregation between the binder material particles C2 can be suppressed by providing the composite particles C1 in which the binder material particles C2 and the inorganic oxide particles C3 are integrated.

[0035] Although in the binder C10, binder material particles C2 not attached with inorganic oxide particles C3, in other words, binder material particles C2 not constituting the composite particles C1, may also be included, the proportion of the binder material particles C2 constituting the composite particles C1 in the total binder material particles C2 included in the binder C10 is preferably 50% or more by mass, more preferably 60% or more by mass, and further preferably 70% or more by mass.

[0036] Thereby, aggregation of the binder material particles C2 with each other can be more effectively suppressed, and a molded body with excellent strength can be manufactured.

[0037] 1.1.2. Inorganic Oxide Particles

[0038] The binder C10 contains inorganic oxide particles C3. In addition, the binder C10 contains composite particles C1 in which the inorganic oxide particles C3 and the binder material particles C2 are integrated. Thus, when using the binder C10 to bond fibers to each other to manufacture a molded body, aggregation of the composite particles C1 can be suppressed and a high dispersion state can be maintained. Therefore, the particle surface of the composite particles C1 as the charged part can be widened. In addition, by including the inorganic oxide particles C3 in the composite particles C1, the surface of the composite particles C1 can be kept in a dry state, and the loss of charge due to moisture can be suppressed. As a result of these situations, the binder C10 can be effectively charged, the adhesion of the binder C10 to the fibers becomes larger, and the bonding force between the fibers also increases, so that a molded body with excellent strength can be manufactured.

[0039] The inorganic oxide particles C3 are mainly composed of inorganic oxides. As materials constituting the inorganic oxides, metal oxides such as silica, alumina, zirconia, titanium dioxide, and magnetite can be cited. Among these substances, silica, alumina, and titanium dioxide are preferred in terms of excellent chemical and thermal stability, and silica is more preferred.

[0040] Since the inorganic oxide particles C3 are mainly composed of silica, the dispersibility of the composite particles C1 is further improved. As a result, it is possible to effectively suppress the unintentional aggregation of the binder C10 during storage of the binder C10 or transportation of the binder C10 during the manufacturing process of the molded body. In addition, since silica has a relatively small specific gravity among inorganic oxides, the fluidity of the composite particles C1 is improved. In addition, silica is a material that is not likely to have an adverse effect on the color tone of the molded body manufactured using the binder C10. In particular, when the molded body is paper, this effect is significantly exerted.

[0041] In addition to containing inorganic oxides, the inorganic oxide particles C3 also contain carbon. Thereby, the surface free energy of the inorganic oxide particles C3 can be effectively reduced. As a result, when the binder C10 is used in the manufacture of the formed body, the binder C10 can be better fused to the surface of the fiber. Thereby, the binder C10 can be evenly distributed over the entire formed body, and the strength of the formed body can be made more excellent.

[0042] Preferably, the carbon contained in the inorganic oxide particles C3 is carbon derived from a hydrocarbon group. More specifically, the inorganic oxide particles C3 are hydrophobized inorganic oxide particles C3 obtained by treating mother particles composed of inorganic oxides with a surface treatment agent having a hydrocarbon group. That is, preferably, the carbon contained in the hydrophobized inorganic oxide particles C3 is carbon derived from a hydrocarbon group imparted to the surface of the inorganic oxide by surface treatment. Since the inorganic oxide particles C3 are such hydrophobized inorganic oxide particles C3, the surface free energy of the inorganic oxide particles C3 can be more effectively reduced. As a result, when the binder C10 is used to bind the fibers to each other to form a formed body, the binder C10 can be better fused to the surface of the fiber. Thereby, the binder C10 can be evenly distributed over the entire formed body, and the strength of the formed body can be made more excellent.

[0043] As the surface treatment agent, as long as it is a surface treatment agent having a hydrocarbon group, it can be used under conditions not particularly limited. For example, fluorine-containing compounds, silicon-containing compounds, etc. can be cited. By using such a surface treatment agent, carbon can be effectively introduced into the mother particles, and the surface free energy of the inorganic oxide particles C3 can be more effectively reduced. Thereby, the fluidity of the binder C10 and the ease of treatment are improved. Moreover, the binder C10 can be more evenly distributed on the finally obtained formed body, and the strength of the formed body can be made more excellent.

[0044] As the fluorine-containing compound, for example, perfluoropolyether, fluorine-modified silicone oil, etc. can be cited.

[0045] As the silicon-containing compound, for example, silane coupling agent, titanate coupling agent, silicone oil, cyclic siloxane, hexamethyldisilazane, alkyldichlorosilane, etc. can be cited. Among them, due to the high treatment effect and the difficulty of elution or exudation of the surface treatment agent, preferably, treatment is carried out with hexamethyldisilazane or alkyldichlorosilane. Since the reactivity of the above-mentioned treatment agent is high, even when the amount of reactive groups such as silanol groups present on the surface of the inorganic oxide particles C3 is small, the necessary amount of carbon can be introduced into the inorganic oxide particles C3 with an appropriate treatment efficiency.

[0046] When using a surface treatment agent, either one surface treatment agent or multiple surface treatment agents can be used.

[0047] When using multiple surface treatment agents, for a single mother particle, multiple surface treatment agents can also be used, and the binder C10 can also contain particles obtained by treating inorganic oxide particles C3 with different surface treatment agents.

[0048] Relative to 100 parts by mass of the mother particles contained in the binder C10, the content of the surface treatment agent is preferably 0.5 parts by mass or more and 7.0 parts by mass or less, more preferably 1.0 parts by mass or more and 5.0 parts by mass or less.

[0049] By treating the mother particles composed of inorganic oxides with a surface treatment agent having a hydrocarbon group, carbon is introduced into the mother particles via chemical bonds, and inorganic oxide particles C3 containing 2% or more of carbon by mass percentage can be obtained.

[0050] In addition, the inorganic oxide particles C3 contain 2.0% or more of carbon by mass relative to the mass of the inorganic oxide particles C3. The inorganic oxide particles C3 are preferably those containing 2.5% or more of carbon by mass relative to the mass of the inorganic oxide particles C3, more preferably those containing 3.0% or more of carbon by mass. In addition, the inorganic oxide particles C3 are preferably those containing 7.0% or less of carbon by mass relative to the mass of the inorganic oxide particles C3, more preferably those containing 5.0% or less of carbon by mass. In addition, the carbon content of the inorganic oxide particles C3 can be quantified based on the reduction in mass when the inorganic oxide particles are burned.

[0051] The average particle size of the inorganic oxide particles C3 is preferably 1.0 nm or more and 20.0 nm or less, more preferably 3.0 nm or more and 18.0 nm or less, and further preferably 5.0 nm or more and 10.0 nm or less.

[0052] As a result, the situation where excessive unevenness is generated on the surface of the composite particle C1 in which the inorganic oxide particles C3 are attached to the surface of the binder particle C2 is appropriately suppressed. Therefore, when the composite particle C1 is mixed with fibers, the fluidity of the binder C10 can be made more excellent, and the composite particle C1 and the fibers can be mixed more uniformly. In addition, the inorganic oxide particles C3 can be more appropriately attached to the surface of the binder particle C2, and the situation where the inorganic oxide particles C3 are unintentionally detached from the surface of the binder particle C2 or unintentionally buried inside the binder particle C2 can be prevented.

[0053] Moreover, since the average particle size of the inorganic oxide particles C3 is 1.0 nm or more and 20.0 nm or less, the effect of suppressing the aggregation of the binder particles C2 and improving the dispersibility of the composite particles C1 by integrating the binder particles C2 and the inorganic oxide particles C3 is more significantly exerted. That is, a repulsive force acts between the inorganic oxide particles C3, thereby suppressing the aggregation of the binder particles C2 and improving the dispersibility of the composite particles C1.

[0054] Although the inorganic oxide particles C3 not attached to the binder particles C2, in other words, the inorganic oxide particles C3 not constituting the composite particles C1, may also be included in the binder C10, the proportion of the inorganic oxide particles C3 constituting the composite particles C1 in the inorganic oxide particles C3 included in the binder C10 is preferably 50% or more by mass, more preferably 60% or more by mass, and further preferably 70% or more by mass. Thereby, the aggregation of the binder particles C2 is suppressed, and the dispersibility of the composite particles C1 is improved.

[0055] As the inorganic oxide particles C3, commercially available products can also be used. Examples of the commercially available products of the inorganic oxide particles C3 include fused silica manufactured by Tokuyama Corporation, trade names: Leorosil (registered trademark) DM-30S, KS-20SC, HM-20L, HM-30S, ZD-30ST, and fused silica manufactured by Nippon Aerosil Co., Ltd., trade names: Aerosil (registered trademark) RY50, RY-51, NY-50, NY-50L, RA200H, RA200HS, etc.

[0056] The mass of the inorganic oxide particles C3 in the binder C10 is preferably 0.3% or more and 8.0% or less by mass relative to the mass of the binder particles C2, more preferably 0.5% or more and 5.0% or less by mass, and further preferably 0.7% or more and 4.0% or more by mass.

[0057] Thereby, the dispersion stability of the composite particles C1 is improved. That is, by setting the mass of the inorganic oxide particles C3 relative to the mass of the binder particles C2 within the above range, the aggregation of the composite particles C1 and the formation of coarse particles are suppressed, so that the dispersion stability of the composite particles C1 is more excellent.

[0058] 1.1.3. Other structures

[0059] The binder C10 can also be configured to include the aforementioned composite particles C1 and further include other structures. For example, the binder C10 can also be configured to include the aforementioned composite particles C1, and include binder particles C2 to which inorganic oxide particles C3 are not attached, and can also include inorganic oxide particles C3 that are not attached to the binder particles C2.

[0060] However, the content rate of the composite particles C1 in the binder C10 is preferably 50% or more by mass, more preferably 70% or more by mass, and further preferably 80% or more by mass. Thus, the aforementioned effects are more significantly exerted.

[0061] 1.1.4. Other Conditions

[0062] Preferably, the binder C10 satisfies the following conditions.

[0063] For example, the content rate of the binder particles C2 in the binder C10 is preferably 90.0% or more and 99.9% or less by mass, more preferably 95.0% or more and 99.7% or less by mass, and further preferably 97.0% or more and 99.4% or less by mass.

[0064] Thus, the aforementioned effects are more significantly exerted.

[0065] In addition, the content rate of the inorganic oxide particles C3 in the binder C10 is preferably 0.1% or more and 10.0% or less by mass, more preferably 0.3% or more and 5.0% or less by mass, and further preferably 0.6% or more and 3.0% or less by mass.

[0066] Thus, the effects obtained by integrating the binder particles C2 and the inorganic oxide particles C3 are more significantly exerted, that is, the effects that repulsive forces act between the inorganic oxide particles C3 to inhibit the aggregation of the binder particles C2 with each other and improve the dispersibility of the composite particles C1.

[0067] 2. Manufacturing Method of Binder

[0068] The binder C10 can be manufactured by mixing the binder particles C2 and the inorganic oxide particles C3 using methods well-known to those skilled in the art.

[0069] In the case where starch granules are used as the binding material particles C2, the weight-average molecular weight of starch can be adjusted by the above-described method, and the average particle size of the starch granules can be adjusted by classification using a known method, and used for the production of the binder C10. In addition, carbon is introduced into the inorganic oxide particles C3 by preparing the material of the above-described inorganic oxide particles C3 and using a surface treatment agent containing a hydrocarbon. Further, as a method for introducing carbon into the inorganic oxide particles C3, a known method for introducing a hydrophobic substance into the surface can be used without particular limitation.

[0070] Using a stirrer such as a super mixer, a Henschel mixer, or a turbulator, the inorganic oxide particles C3 into which a predetermined amount of carbon has been introduced and the binding material particles C2 prepared in the above-described manner are mixed and stirred. By stirring the binding material particles C2 and the inorganic oxide particles C3 under a fixed shearing force, frictional heat is generated on the particle surface, and the binding material particles C2 and the inorganic oxide particles C3 are integrated. After mixing, sieving can be performed using a sieve with a mesh of 20 μm to 100 μm, and the binder C10 can be obtained.

[0071] 3. Method for manufacturing a formed body

[0072] Hereinafter, a method for manufacturing a formed body in which fibers are bonded to each other using the binder C10 to form a formed body will be described. The method for manufacturing a formed body includes: a stacking step of stacking a mixture containing fibers and the binder C10; a humidifying step of imparting moisture to the stacked mixture; and a forming step of obtaining a formed body by heating and pressing the mixture to which moisture has been imparted.

[0073] 3.1. Stacking step

[0074] In the stacking step, a mixture containing fibers and the binder C10 is stacked in the air.

[0075] Although the mixing ratio of the fibers and the binder C10 in this step is not particularly limited, the content of the binder C10 in the mixture obtained in this step is preferably 1% by mass or more and 50% by mass or less, more preferably 2% by mass or more and 45% by mass or less, and still more preferably 3% by mass or more and 40% by mass or less.

[0076] Thereby, the fiber content in the finally obtained formed body can be made sufficiently high, and the strength of the formed body can be made more excellent. In addition, the conveyance of the binder C10 in the manufacturing process of the formed body can be carried out more smoothly.

[0077] In this process, the fibers mixed with the binder C10 may also be, for example, fibers that have been pre-humidified prior to the subsequent humidification process, i.e., the process of performing humidification treatment on the mixture. In addition, the fibers may be fibers that are humidified during the stacking of the mixture obtained by this mixing, starting from the mixing with the binder C10.

[0078] In the above-described case, the moisture content in the fibers supplied to this process is preferably 0.1% by mass or more and 12.0% by mass or less, more preferably 0.2% by mass or more and 10.0% by mass or less, and further preferably 0.3% by mass or more and 9.0% by mass or less.

[0079] Thereby, for example, it is possible to effectively prevent the situation where the fibers are adversely affected by static electricity before this process, for example, it is possible to effectively prevent the situation where the fibers adhere to the wall surface of the manufacturing apparatus of the formed body due to static electricity, etc. In addition, it is possible to mix the fibers and the binder C10 more uniformly.

[0080] The fibers are the main component of the formed body manufactured by the manufacturing method of the formed body, and are components that greatly contribute to the maintenance of the shape of the formed body and have a great influence on the properties such as the strength of the formed body.

[0081] Although the fibers may also be fibers made of any material, fibers that can maintain the fiber state even by heating in the forming process are preferred.

[0082] Although the fibers may also be synthetic fibers made of synthetic resins such as polypropylene, polyester, and polyurethane, natural fibers, especially cellulose fibers, are more preferred.

[0083] Cellulose fibers are fibers that can be recycled. As the raw material of the fibers, by recycling cellulose fibers such as waste paper and old cloth that have been used more than once, it is related to the protection of forest resources. In addition, cellulose fibers are fibers with particularly high theoretical strength among various fibers, and are also advantageous from the viewpoint of further improving the strength of the formed body.

[0084] Although cellulose fibers are usually fibers mainly composed of cellulose, they may also contain components other than cellulose. As such components, for example, hemicellulose, lignin, etc. can be cited.

[0085] In particular, it is preferred that the fibers are composed of a substance containing at least one chemical structure among a hydroxyl group, a carbonyl group, and an amino group.

[0086] Thus, for example, when starch is used as the binding material, hydrogen bonds are likely to form between the fibers and the binding material, enabling the bonding strength between the fibers and the binder C10 to be more excellent, and enabling the strength of the entire shaped body, such as the breaking strength of the sheet-shaped shaped body, to be more excellent.

[0087] In addition, as the cellulose fiber, a fiber that has been subjected to treatments such as bleaching can also be used.

[0088] In addition, the fiber can also be a fiber that has been subjected to treatments such as ultraviolet irradiation treatment, ozone treatment, and plasma treatment. Thus, the hydrophilicity of the fiber can be improved, and the affinity with the binding material can be improved. More specifically, through these treatments, functional groups such as hydroxyl groups can be introduced to the surface of the fiber, and hydrogen bonds can be formed more effectively between the fiber and the binding material.

[0089] Although the average length of the fiber is not particularly limited, it is preferably 0.1 mm or more and 50.0 mm or less, more preferably 0.2 mm or more and 5.0 mm or less, and further preferably 0.3 mm or more and 3.0 mm or less.

[0090] Thus, the shape stability, strength, etc. of the manufactured shaped body can be made more excellent.

[0091] Although the average thickness of the fiber is not particularly limited, it is preferably 0.005 mm or more and 0.500 mm or less, more preferably 0.010 mm or more and 0.050 mm or less.

[0092] Thus, the shape stability, strength, etc. of the manufactured shaped body can be made more excellent. In addition, the situation of generating unintended unevenness on the surface of the shaped body can be more effectively prevented.

[0093] Although the average aspect ratio of the fiber, that is, the ratio of the average length to the average thickness, is not particularly limited, it is preferably 10 or more and 1000 or less, more preferably 15 or more and 500 or less.

[0094] Thus, the shape stability, strength, etc. of the manufactured shaped body can be made more excellent. In addition, the situation of generating unintended unevenness on the surface of the manufactured shaped body can be more effectively prevented.

[0095] 3.2. Humidifying process

[0096] In the humidifying process, water is given to the mixture stacked in the stacking process, that is, the mixture containing fibers and the binder C10, to humidify it.

[0097] Accordingly, in the subsequent forming process, the bonding strength between the fibers and the binding material and the bonding strength between the fibers via the binding material can be made excellent, and the strength of the finally obtained formed body can be made sufficiently excellent. In addition, the forming in the forming process can be appropriately carried out under relatively stable conditions.

[0098] Although the method of humidifying the mixture is not particularly limited, it is preferably carried out in a non-contact manner. For example, methods such as placing the mixture in a high-humidity environment, passing the mixture through a high-humidity space, blowing a mist of a liquid containing water onto the mixture, and passing the mixture through a space in which a mist of a liquid containing water floats can be cited, and one or more methods selected from these methods can be combined and carried out. More specifically, the humidification of the mixture can be carried out using various humidifiers such as vaporization type and ultrasonic type. The humidification of the mixture can also be carried out in multiple stages, for example, during the process of manufacturing the formed body. In addition, in the liquid containing water, for example, preservatives, antifungal agents, insecticides, etc. can also be contained.

[0099] Although the amount of moisture imparted to the mixture in the humidification process is not particularly limited, relative to 100 parts by mass of the mixture supplied to the humidification process, it is preferably 1 part by mass or more and 50 parts by mass or less, more preferably 5 parts by mass or more and 40 parts by mass or less, and still more preferably 10 parts by mass or more and 30 parts by mass or less.

[0100] Accordingly, compared with the existing papermaking method, a formed body with sufficient strength can be manufactured with significantly less moisture, and the effects brought by the present invention can be more significantly exerted.

[0101] 3.3. Forming process

[0102] In the forming process, the mixture humidified in the humidification process is pressurized and heated. Thereby, a formed body is obtained. In addition, the humidification process and the forming process can also be carried out simultaneously.

[0103] Although the pressure applied to the mixture in the forming process is not particularly limited, it is preferably 0.1 MPa or more and 100.0 MPa or less, more preferably 0.3 MPa or more and 80.0 MPa or less.

[0104] Accordingly, the binder C10 can be better fused to the surface of the fibers. As a result, the strength of the manufactured formed body can be made more excellent.

[0105] Although the heating temperature in the forming process is not particularly limited, it is preferably 50°C or higher and 200°C or lower, more preferably 60°C or higher and 150°C or lower, and further preferably 70°C or higher and 120°C or lower.

[0106] Thereby, it is possible to effectively prevent unintentional deterioration, modification, etc. of the fibers or the components of the binder C10, and at the same time, the binder C10 can be better integrated with the surface of the fibers. As a result, the strength and reliability of the manufactured formed body can be made more excellent. In addition, it is also preferable from the viewpoint of energy saving. In particular, when the combined material particles C2 are particles composed of a material containing starch as a combined material, the gelatinization of the starch being absorbed can be appropriately carried out, and the case where the constituent materials of the formed body are unintentionally deteriorated can be effectively prevented, etc.

[0107] The forming process can be carried out, for example, using hot stamping, hot rollers, etc. Thereby, it is possible to effectively prevent unintentional deterioration, modification, etc. of the fibers or the components of the binder C10, and at the same time, the binder C10 can be better integrated with the surface of the fibers. As a result, the strength and reliability of the manufactured formed body can be made more excellent.

[0108] Regarding the binder C10, since the inorganic oxide particles C3 contain carbon in a mass percentage of 2% or more with respect to the mass of the inorganic oxide particles C3, the angle of repose of the binder C10 can be reduced. Thereby, in the manufacturing method of the formed body, when the binder C10 is used as the binder C10 that binds the fibers to each other, the composite particles C1 and the fibers can be uniformly mixed. Therefore, a formed body with the binder C10 uniformly distributed can be obtained, and a formed body with sufficient strength can be manufactured.

[0109] The manufacturing method of the formed body described above can be appropriately implemented, for example, using the following manufacturing apparatus for the formed body.

[0110] 4. Manufacturing Apparatus for Formed Body

[0111] Next, the manufacturing apparatus for the formed body will be described.

[0112] Figure 2 Fig. is a schematic explanatory diagram showing the structure of a manufacturing apparatus that is preferable in the implementation of the manufacturing method of the formed body. In addition, hereinafter, for the sake of convenience of explanation, sometimes the upper side in Figure 2 is referred to as "upper" or "above", the lower side is referred to as "lower" or "below", the left side is referred to as "left" or "upstream side", and the right side is referred to as "right" or "downstream side".

[0113] In the following description, as an example of a manufacturing apparatus for a formed body, an example of a sheet manufacturing apparatus 100 that manufactures a sheet S as the formed body will be described.

[0114] As Figure 2 shown, the sheet manufacturing apparatus 100, which is a manufacturing apparatus for a formed body, includes a raw material supply unit 11, a coarse crushing unit 12, a defibrating unit 13, a screening unit 14, a first sheet forming unit 15, a subdividing unit 16, a mixing unit 17, an unwinding unit 18, a second sheet forming unit 19, a sheet forming unit 20, a cutting unit 21, and a storage unit 22. In addition, the sheet manufacturing apparatus 100 includes a humidifying unit 231, a humidifying unit 232, a humidifying unit 233, and a humidifying unit 234.

[0115] The operations of the respective units included in the sheet manufacturing apparatus 100 are controlled by a control unit (not shown).

[0116] The method for manufacturing the sheet S as the formed body includes a raw material supply process, a coarse crushing process, a defibrating process, a screening process, a first sheet forming process, a dividing process, a mixing process, an unwinding process, a second sheet forming process, a humidifying process, a sheet forming process, and a cutting process. Moreover, the sheet manufacturing apparatus 100 can sequentially execute these processes.

[0117] Hereinafter, the structures of the respective units included in the sheet manufacturing apparatus 100 will be described.

[0118] The raw material supply unit 11 is a part that performs the raw material supply process of supplying the sheet-like material M1 to the coarse crushing unit 12. The sheet-like material M1 is a sheet-like material containing fibers such as cellulose fibers.

[0119] The coarse crushing unit 12 is a part that performs the coarse crushing process of coarsely crushing the sheet-like material M1 supplied from the raw material supply unit 11 in air or other gases. The coarse crushing unit 12 has a pair of coarse crushing blades 121 and a hopper 122.

[0120] The pair of coarse crushing blades 121 can rotate in opposite directions to each other, and coarsely crush, that is, cut, the sheet-like material M1 between them to produce coarse fragments M2. The shape or size of the coarse fragments M2 is preferably suitable for the defibrating process in the defibrating unit 13. For example, it is preferably a small piece with a side length of 100 mm or less, and more preferably a small piece with a side length of 10 mm or more and 70 mm or less.

[0121] The hopper 122 is disposed below the pair of coarse crushing blades 121 and is, for example, funnel-shaped. Thereby, the hopper 122 can receive the coarse fragments M2 that are coarsely crushed by the coarse crushing blades 121 and fall.

[0122] Furthermore, a humidifying unit 231 is disposed above the hopper 122 so as to be adjacent to the pair of coarse crushing blades 121. The humidifying unit 231 is a device for humidifying the coarse fragments M2 in the hopper 122. The humidifying unit 231 is composed of a vaporizing humidifier having a filter (not shown) containing moisture, and the humidified air with increased humidity is supplied to the coarse fragments M2 by passing air through the filter. By supplying the humidified air to the coarse fragments M2, it is possible to control the coarse fragments M2 from being attached to the hopper 122 or the like due to static electricity.

[0123] The hopper 122 is connected to the defibrating unit 13 via a pipe 241 as a flow path. The coarse fragments M2 collected in the hopper 122 pass through the pipe 241 and are transported to the defibrating unit 13.

[0124] The defibration section 13 is a section for carrying out a defibration process in which the coarse fragments M2 are defibrated in a gas such as air, i.e., in a dry manner. The defibration process in the defibration section 13 can generate a defibrated material M3 from the coarse fragments M2. Here, "defibration" means that the coarse fragments M2 formed by bonding a plurality of fibers are disentangled into individual fibers. And, the disentangled material becomes the defibrated material M3. The defibrated material M3 is in the shape of a line or a belt. In addition, the defibrated materials M3 may exist in a state of being entangled with each other and forming a block, i.e., in a state of forming a so-called "clump".

[0125] In the present embodiment, the defibrating unit 13 is composed of, for example, an impeller mill having a rotor that rotates at high speed and a bushing located on the outer periphery of the rotor. The coarse fragments M2 that flow into the defibrating unit 13 are sandwiched between the rotor and the bushing and are defibrated.

[0126] The defibrating unit 13 can generate a flow of air, i.e., an airflow, from the coarse crushing unit 12 toward the screening unit 14 by the rotation of the rotor. Thus, the coarse crushing pieces M2 can be sucked from the pipe 241 into the defibrating unit 13. After the defibration process, the defibrated material M3 can be sent to the screening unit 14 through the pipe 242.

[0127] A blower 261 is provided in the middle of the tube 242. The blower 261 is an airflow generating device that generates an airflow toward the screening unit 14. Thus, the delivery of the defibrated material M3 to the screening unit 14 is promoted.

[0128] The screening section 14 is a part for implementing a screening process for screening the defibrated material M3 according to the length of the fiber. In the screening section 14, the defibrated material M3 is screened into a first screened material M4-1 and a second screened material M4-2 larger than the first screened material M4-1. The first screened material M4-1 is a material of a size suitable for manufacturing the subsequent sheet S. The second screened material M4-2 includes, for example, a material that is insufficiently defibrated or a material in which the defibrated fibers are excessively agglomerated.

[0129] The screening unit 14 has a drum unit 141 and a housing unit 142 that houses the drum unit 141.

[0130] The drum unit 141 is a sieve formed of a cylindrical net body and rotating about its central axis. In this drum unit 141, the defibrated material M3 flows in. Moreover, by rotating the drum unit 141, the defibrated material M3 smaller than the mesh of the net is screened as the first screened material M4-1, and the defibrated material M3 larger than the mesh of the net is screened as the second screened material M4-2.

[0131] The first screened material M4-1 falls from the drum unit 141.

[0132] The second screened material M4-2 is sent to a flow path connected to the drum unit 141, that is, the pipe 243. The side of the pipe 243 opposite to the drum unit 141 is connected to the pipe 241. The second screened material M4-2 that has passed through the pipe 243 converges with the coarse fragments M2 in the pipe 241, and thus flows into the defibrating unit 13 together with the coarse fragments M2. Thereby, the second screened material M4-2 returns to the defibrating unit 13 and is subjected to defibrating treatment together with the coarse fragments M2.

[0133] In addition, the first screened material M4-1 falls while being dispersed in the air and falls toward a separating unit located below the drum unit 141, that is, the first sheet forming unit 15. The first sheet forming unit 15 is a part that performs the first sheet forming process of forming the first sheet M5 from the first screened material M4-1. The first sheet forming unit 15 has a mesh belt 151 as a separating belt, three tension rollers 152, and a suction unit 153.

[0134] The mesh belt 151 is a seamless belt and accumulates the first screened material M4-1. The mesh belt 151 is wound around the three tension rollers 152. Moreover, the first screened material M4-1 on the mesh belt 151 is conveyed to the downstream side by the rotational drive of the tension rollers 152.

[0135] The first screened material M4-1 is larger than the mesh of the mesh belt 151. Thus, the first screened material M4-1 is restricted from passing through the mesh belt 151, and therefore, can be accumulated on the mesh belt 151. In addition, since the first screened material M4-1 is accumulated on the mesh belt 151 and is conveyed to the downstream side together with the mesh belt 151, the first sheet M5 is formed into a layer.

[0136] In addition, in the first sieve M4-1, there are sometimes mixtures such as dust or dirt. For example, dust or dirt may be mixed in with the sheet-like material M1 when the sheet-like material M1 is supplied from the raw material supply unit 11 to the coarse crushing unit 12. This dust or dirt is smaller than the mesh of the mesh belt 151. Thus, the dust or dirt passes through the mesh belt 151 and further falls downward.

[0137] The suction unit 153 can suck air from below the mesh belt 151. Thus, the dust or dirt passing through the mesh belt 151 can be sucked together with the air.

[0138] The suction unit 153 is connected to the recovery unit 27 via a pipe 244 serving as a flow path. The dust or dirt sucked by the suction unit 153 is recovered into the recovery unit 27.

[0139] A pipe 245 serving as a flow path is also connected to the recovery unit 27. In addition, a blower 262 is provided in the middle of the pipe 245. The working of this blower 262 can generate a suction force in the suction unit 153. Thus, the formation of the first sheet M5 on the mesh belt 151 is promoted. This first sheet M5 becomes a sheet after dust or dirt and the like have been removed. In addition, the dust or dirt passes through the pipe 244 due to the working of the blower 262 and then reaches the recovery unit 27.

[0140] The housing part 142 is connected to the humidifying part 232. The humidifying part 232 is composed of the same vaporizing humidifier as the humidifying part 231. Thus, humidified air is supplied into the housing part 142. The first sieve M4-1 can be humidified by using this humidified air. Thus, it is also possible to suppress the situation where the first sieve M4-1 adheres to the inner wall of the housing part 142 due to electrostatic force.

[0141] A humidifying part 235 is arranged on the downstream side of the screening part 14. The humidifying part 235 is composed of an ultrasonic humidifier that sprays water in a spray manner. Thus, moisture can be supplied to the first sheet M5. Therefore, the moisture content of the first sheet M5 is adjusted. Through this moisture adjustment, it is possible to suppress the adsorption of the first sheet M5 to the mesh belt 151 due to electrostatic force. Thus, the first sheet M5 is easily peeled off from the mesh belt 151 at the position where the mesh belt 151 is turned back at the tension roller 152.

[0142] Downstream of the humidifying section 235, a subdividing section 16 is arranged. The subdividing section 16 is a part that performs a dividing process of dividing the first sheet M5 peeled off from the mesh belt 151. The subdividing section 16 has a propeller 161 rotatably supported and a housing section 162 that houses the propeller 161. Moreover, the first sheet M5 can be divided by being drawn into the rotating propeller 161. The divided first sheet M5 becomes a subdivided body M6. In addition, the subdivided body M6 descends within the housing section 162.

[0143] The housing section 162 is connected to the humidifying section 233. The humidifying section 233 is composed of the same vaporizing humidifier as the humidifying section 231. Thus, humidified air is supplied into the housing section 162. This humidified air can also be used to suppress the situation where the subdivided body M6 adheres to the propeller 161 or the inner wall of the housing section 162 due to electrostatic force.

[0144] Downstream of the subdividing section 16, a mixing section 17 is arranged. The mixing section 17 is a part that performs a mixing process of mixing the subdivided body M6 and the resin P1. The mixing section 17 has a binder supply section 171, a pipe 172 as a flow path, and a blower 173.

[0145] The pipe 172 is a flow path that connects the housing section 162 of the subdividing section 16 and the housing section 182 of the unwinding section 18 and through which the mixture M7 of the subdivided body M6 and the binder C10 passes.

[0146] In the middle of the pipe 172, the binder supply section 171 is connected. The binder supply section 171 has a screw feeder 174. By rotating the screw feeder 174, the binder C10 can be supplied to the pipe 172. The binder C10 supplied to the pipe 172 is mixed with the subdivided body M6 to become the mixture M7.

[0147] In addition, in the substance supplied from the binder supply section 171, together with the binder C10, for example, a colorant for coloring the fibers, an aggregation inhibitor for suppressing the aggregation of the fibers or the binder C10, a flame retardant for making the fibers, etc. difficult to burn, etc. may also be included.

[0148] Moreover, in the middle of the pipe 172 and on the downstream side compared to the binder supply section 171, a blower 173 is provided. The blower 173 can generate an air flow toward the unwinding section 18. This air flow can be used to stir the subdivided body M6 and the binder C10 in the pipe 172. Thus, the mixture M7 can flow into the unwinding section 18 in a state where the subdivided body M6 and the binder C10 are uniformly dispersed. In addition, the subdivided body M6 in the mixture M7 is unwound during the process of passing through the pipe 172 and thus becomes finer fibrous.

[0149] The unwinding section 18 is the part that performs the unwinding process of unwinding the fibers intertwined with each other in the mixture M7. The unwinding section 18 has a drum section 181 and a casing section 182 that houses the drum section 181.

[0150] The drum section 181 is a sieve formed of a cylindrical net body and rotating around the central axis of the net body. The mixture M7 flows into the drum section 181. Moreover, by rotating the drum section 181, fibers and the like in the mixture M7 smaller than the mesh of the net can pass through the drum section 181. At this time, the mixture M7 is unwound.

[0151] The casing section 182 is connected to the humidifying section 234. The humidifying section 234 is composed of the same vaporizing humidifier as the humidifying section 231. Thus, humidified air is supplied into the casing section 182. The inside of the casing section 182 can be humidified using this humidified air, and thus, the situation where the mixture M7 adheres to the inner wall of the casing section 182 due to electrostatic force can also be suppressed.

[0152] The mixture M7 unwound by the drum section 181 is dispersed and falls in the gas and falls toward the second sheet forming section 19 located below the drum section 181. The second sheet forming section 19 is the part that performs the second sheet forming process of forming the second sheet M8 from the mixture M7. The second sheet forming process in the present embodiment is a stacking process of stacking the mixture M7 containing fibers and the binder C10 in the air. The second sheet forming section 19 has a mesh belt 191 as a separating belt, a tension roller 192, and a suction section 193.

[0153] The mesh belt 191 is a seamless belt and is for stacking the mixture M7. The mesh belt 191 is wound around four tension rollers 192. Moreover, the mixture M7 on the mesh belt 191 is conveyed to the downstream side by the rotational drive of the tension roller 192.

[0154] In addition, almost all of the mixture M7 on the mesh belt 191 is larger than the mesh of the mesh belt 191. Thus, the mixture M7 is restricted from passing through the mesh belt 191, and thus, can be stacked on the mesh belt 191. In addition, since the mixture M7 is stacked on the mesh belt 191 and conveyed to the downstream side together with the mesh belt 191, the second sheet M8 is formed into a layer.

[0155] The suction section 193 can suck air from below the mesh belt 191. Thus, the mixture M7 can be sucked onto the mesh belt 191, and thus, the stacking of the mixture M7 onto the mesh belt 191 is promoted.

[0156] A pipe 246 serving as a flow path is connected to the suction part 193. In addition, a blower 263 is provided midway in the pipe 246. A suction force can be generated in the suction part 193 by the operation of the blower 263.

[0157] A humidifying part 236 is arranged on the downstream side of the unwinding part 18. The humidifying part 236 is the part where the aforementioned humidifying process is carried out. The humidifying part 236 is composed of the same ultrasonic humidifier as the humidifying part 235. Thus, moisture can be supplied to the second sheet M8, and accordingly, the moisture content of the second sheet M8 is adjusted. Through this moisture adjustment, the bonding strength between the fibers and the binding material in the sheet S as the finally obtained formed body can be made appropriate.

[0158] In addition, through humidification, the adsorption of the second sheet M8 to the mesh belt 191 due to electrostatic force can be suppressed. Thus, the second sheet M8 is easily peeled off from the mesh belt 191 at the position where the mesh belt 191 is turned back by the tension roller 192.

[0159] A sheet forming part 20 is arranged on the downstream side of the second sheet forming part 19. The sheet forming part 20 is the part where the forming process of forming the sheet S from the second sheet M8, that is, the sheet forming process, is carried out. The sheet forming part 20 has a pressing part 201 and a heating part 202.

[0160] The pressing part 201 has a pair of calender rolls 203 and can press the second sheet M8 between the pair of calender rolls 203. Thus, the density of the second sheet M8 increases. Moreover, the second sheet M8 is conveyed toward the heating part 202. In addition, one of the pair of calender rolls 203 is a driving roll driven by the operation of a motor (not shown), and the other is a driven roll.

[0161] The heating part 202 has a pair of heating rolls 204 and can heat and press the second sheet M8 between the pair of heating rolls 204. Through this heating and pressing, the binder C10 melts in the second sheet M8, and the fibers are bonded to each other via the melted binder C10. Thus, the sheet S as the formed body is formed. Moreover, the sheet S is conveyed toward the cutting part 21. In addition, one of the pair of heating rolls 204 is a driving roll driven by the operation of a motor (not shown), and the other is a driven roll.

[0162] A cutting part 21 is arranged on the downstream side of the sheet forming part 20. The cutting part 21 is the part where the cutting process of cutting the sheet S is carried out. The cutting part 21 has a first cutter 211 and a second cutter 212.

[0163] The first cutter 211 cuts the sheet S in a direction crossing the conveying direction of the sheet S.

[0164] The second cutter 212 cuts the sheet S on the downstream side of the first cutter 211 in a direction parallel to the conveying direction of the sheet S.

[0165] Through the cutting by such first cutter 211 and second cutter 212, the sheet S as a formed body of a desired size is obtained. Moreover, this sheet S is further conveyed toward the downstream side and stored in the storage unit 22.

[0166] 5. Embodiments

[0167] Next, embodiments of the present invention will be described.

[0168] 5.1. Preparation of the binder

[0169] 5.1.1. Preparation of the raw material starch

[0170] After suspending starch with a weight average molecular weight of 1,300,000 (manufactured by Nippon Starch Chemical Co., Ltd., G-800) in water, sulfuric acid is allowed to act under the condition that the starch is not gelatinized, and they are sufficiently mixed and stirred for 12 hours. They are dried at 50 °C for 24 hours, and after the moisture content is made 10% by mass or less, paste-like starch is obtained by heating at 120 to 180 °C. Then, the paste-like starch is washed with water, freeze-dried, and coarsely pulverized to obtain raw material starch 1 with a weight average molecular weight of 100,000. In addition, for starch with a weight average molecular weight of 1,300,000 (manufactured by Nippon Starch Chemical Co., Ltd., G-800), except for changing the treatment conditions (concentration of sulfuric acid, stirring time), it is treated in the same manner as when manufacturing raw material starch 1, thereby obtaining raw material starch 2 (weight average molecular weight 20,000), raw material starch 3 (weight average molecular weight 55,000), raw material starch 4 (weight average molecular weight 380,000), and raw material starch 5 (weight average molecular weight 470,000) having different weight average molecular weights from raw material starch 1.

[0171] 5.1.2. Preparation of the starch granules

[0172] Using a fluidized bed opposed jet mill (AFG-R counter jet mill, manufactured by Hosokawa Micron Corporation), raw material starch 1 was pulverized under a processing pressure of 4.0 bar to obtain starch particles 1-1 with an average particle size of 10 μm as binder particles C2. In addition, for raw material starches 2 to 5, the same processing as that performed on raw material starch 1 was carried out to obtain starch particles 2-1, 3-1, 4-1, and 5-1, respectively. Moreover, for raw material starch 1, except for changing the processing pressure during pulverization, the same processing as when manufacturing starch particles 1-1 was carried out to obtain starch particles 1-2 with an average particle size of 2 μm (processing pressure 8.0 bar), starch particles 1-3 with an average particle size of 40 μm (processing pressure 1.5 bar), and starch particles 1-4 with an average particle size of 55 μm (processing pressure 1.0 bar).

[0173] 5.1.3. Preparation of Binder

[0174] 99 parts by mass of starch particles 1-1 as binder particles C2 and 1 part by mass of fused quartz as inorganic oxide particles C3 (manufactured by Tokuyama Corporation, trade name: Rheoseal (registered trademark), product number: DM-30S) were filled into a Henschel mixer (FM mixer FM 20C / I manufactured by Nippon Coke Industry Co., Ltd.) and subjected to a mixing process for 10 minutes at a frequency of 60 Hz. Then, screening was carried out using a sieve with a mesh size of 30 μm to prepare binder C10 of composite particle C1 of Example 1 in which starch particles 1-1 as binder particles C2 and fused quartz as inorganic oxide particles C3 were integrated.

[0175] Except for setting the ratio of binder particles C2, inorganic oxide particles C3, and binder particles C2 and inorganic oxide particles C3 as shown in Table 1, binders C10 of Examples 2 to 16 and Comparative Example 1 were prepared in the same manner as in Example 1. In addition, the inorganic oxide particles C3 in Table 1 are as follows.

[0176] · DM-30S, Tokuyama Corporation, Rheoseal, product number: DM-30S, fused quartz

[0177] · HM-20L, Tokuyama Corporation, Rheoseal, product number: HM-20L, fused quartz

[0178] · HM-30S, Tokuyama Corporation, Rheoseal, product number: HM-30S, fused quartz

[0179] · ZD-30ST, Tokuyama Corporation, Rheoseal, product number: ZD-30ST, fused quartz

[0180] ·DM-30 Tokuyama Corporation, Leorosil, Product No.: DM-30, fused quartz

[0181] ·NY-50 Nippon Aerosil Co., Ltd., Aerosil (registered trademark), Product No.: NY-50, fused quartz

[0182] Table 1

[0183]

[0184] 5.1.4. Manufacture of the sheet as a shaped body

[0185] Using the binder of Example 1, a sheet as a shaped body was manufactured.

[0186] A modified machine was prepared by modifying a sheet manufacturing apparatus 100 (PaperLab (registered trademark) A-8000 manufactured by Seiko Epson Corporation) so as to be able to humidify the sheet before pressurization after forming. In addition, as the source of the fibers, a sheet on which a commercial document was printed with an inkjet printer on commercially available copy paper (manufactured by Fuji Xerox Co., Ltd., GR70-W) was used as the sheet-like material M1.

[0187] Next, the above-described sheet-like material M1 was supplied to the raw material supply unit 11 of the sheet manufacturing apparatus 100, and the binder C10 manufactured by the above-described modulation of the binder was supplied to the binder supply unit 171. The operation of the sheet manufacturing apparatus 100 was carried out, and the processes of a coarse crushing process, a defibrillation process, a screening process, a first sheet forming process, a cutting process, a mixing process, an unraveling process, a second sheet forming process as a stacking process, a humidifying process, a sheet forming process as a forming process, and a cutting process were carried out to manufacture an A4-sized sheet S as a shaped body. The basis weight of the obtained sheet S was 90 g / m 2 .

[0188] At this time, adjustment was made so that the finally obtained sheet S as a shaped body became a sheet containing 10 parts by mass of the binder C10 with respect to 90 parts by mass of the fibers.

[0189] Except that the binder of Example 2 to 16 or Comparative Example 1 was used as the binder C10, an A4-sized sheet S as a shaped body was manufactured in the same manner as in Example 1.

[0190] 5.2. Evaluation

[0191] 5.2.1. Fluidity of the binder

[0192] Regarding the binders of Examples 1 to 16 and Comparative Example 1, the angle of repose and compressibility were measured using a powder property evaluation device (Powder Tester (registered trademark) PT-X, manufactured by Hosokawa Micron Corporation). Based on the measurement results, the flowability value, which is the product of the angle of repose [°] and compressibility [%], was calculated and evaluated according to the following criteria. Additionally, it can be said that the smaller the flowability value, the better the flowability.

[0193] A: The flowability value is less than 10.

[0194] B: The flowability value is 10 or more and less than 12.

[0195] C: The flowability value is 12 or more and less than 14.

[0196] D: The flowability value is 14 or more and less than 17.

[0197] E: The flowability value is 17 or more.

[0198] The results are shown in Table 2.

[0199] 5.2.2. Strength of the Formed Body

[0200] A 100 mm × 20 mm strip was cut out from the sheet S as the formed body manufactured in Examples 1 to 16 and Comparative Example 1 above, and the breaking strength was measured in the length direction of the strip. In the measurement of the breaking strength, an autograph AGS-1N manufactured by Shimadzu Corporation was used, and the breaking strength was measured at a tensile speed of 20 mm / sec. Accordingly, the specific tensile strength was calculated and evaluated according to the following criteria. Additionally, it can be said that the larger the specific tensile strength, the better the strength.

[0201] A: The specific tensile strength is 25 Nm / g or more.

[0202] B: The specific tensile strength is 20 Nm / g or more and less than 25 Nm / g.

[0203] C: The specific tensile strength is 15 Nm / g or more and less than 20 Nm / g.

[0204] D: The specific tensile strength is 10 Nm / g or more and less than 15 Nm / g.

[0205] E: The specific tensile strength is less than 10 Nm / g.

[0206] The results are shown in Table 2.

[0207] Table 2

[0208]

[0209] As is clear from Table 2, Examples 1 to 16 achieved good results of Evaluation C or higher in the strength test of the formed body. On the other hand, the strength of the formed body of Comparative Example 1 was Evaluation D, and satisfactory results were not obtained. In addition, in the powder fluidity test, the binders of Examples 1 to 16 also achieved Evaluation C or higher. In contrast, the binder of Comparative Example 1 was Evaluation D, confirming the results of the strength test of the formed body.

[0210] Symbol Explanation

[0211] C10... Binder; C1... Composite particle; C2... Binding material particle; C3... Inorganic oxide particle.

Claims

1. A binder, wherein, the binder is a binder comprising binder material particles and inorganic oxide particles, the binder material particles comprising a binder material that causes fibers to bind to each other by being given moisture, the binder comprises composite particles in which the binder material particles and the inorganic oxide particles are integrated, the inorganic oxide particles comprise carbon and an inorganic oxide, the content of the carbon being 2% by mass or more relative to the mass of the inorganic oxide particles, and the material constituting the inorganic oxide being selected from silica, alumina, zirconia, titanium dioxide, and magnetite.

2. The binder according to claim 1, wherein, the binder material comprises starch having a weight average molecular weight of 50,000 or more and 400,000 or less.

3. The binder according to claim 1 or 2, wherein, the average particle size of the binder material particles is 1.0 μm or more and 50.0 μm or less.

4. The binder according to claim 1, wherein, the average particle size of the inorganic oxide particles is 1.0 nm or more and 20.0 nm or less.

5. The binder according to claim 1, wherein, the mass of the inorganic oxide particles in the binder is 0.5% by mass or more and 5.0% by mass or less relative to the mass of the binder material particles.

6. The binder according to claim 1, wherein, the inorganic oxide particles are particles composed of a material containing silica.

7. A method for manufacturing a shaped body, comprising the following steps: a stacking step of stacking a mixture comprising fibers and the binder according to any one of claims 1 to 6; a humidifying step of giving moisture to the stacked mixture; a shaping step of obtaining a shaped body by heating and pressing the mixture to which moisture has been given.

Images