JP7368249B2 - Thermosetting binder compositions and inorganic fiber products - Google Patents

Description

The present invention relates to a thermosetting binder composition and an inorganic fiber product using the same.

Conventionally, inorganic fiber products made by bonding inorganic fibers such as glass wool, rock wool, and ceramic fibers with binders are used for insulation materials, sound absorbing materials, and various other molded products (automobile roofs, bonnet liners, etc.) . Inorganic fiber products are generally manufactured by attaching a thermosetting binder to inorganic fibers, aggregating them to form an aggregate in the shape of the desired inorganic fiber product, and then heating to harden the thermosetting binder. be done. As a thermosetting binder, one whose main component is a phenolic resin obtained by the reaction of phenols and formaldehyde (hereinafter also referred to as "phenolic resin binder") is relatively inexpensive and has good mechanical strength etc. It is widely used because it produces products with excellent performance.

However, phenolic resin binders have a problem in that formaldehyde is easily released during the manufacturing process of inorganic fiber products and the like. The causes include that formaldehyde used as a raw material in the production of phenol resin remains unreacted, and that formaldehyde is generated during thermal curing of the phenol resin binder.
Therefore, so-called non-formaldehyde type binders that do not use raw materials containing formaldehyde are being considered.
Patent Document 1 proposes a thermosetting binder containing carbohydrates, ammonium salts, and phenols (Patent Document 1). This thermosetting binder can exhibit good binder performance (normal strength after thermosetting, etc.) without using raw materials containing formaldehyde.

Japanese Patent Application Publication No. 2014-173085

However, many of the thermosetting binders disclosed in Patent Document 1 are acidic with a pH of around 4. A thermosetting binder having a pH of around 8 is also described, but according to studies by the present inventors, the pH of this thermosetting binder decreases over time during storage after production and becomes acidic. Therefore, these thermosetting binders may corrode metals (such as iron) that constitute the manufacturing equipment for inorganic fiber products.

One aspect of the present invention is to provide a thermosetting binder composition that exhibits good binder performance without using raw materials containing formaldehyde and does not easily corrode metals, and an inorganic fiber product using the same. purpose.

The present invention has the following aspects.
[1] Contains non-reducing sugars, phenols, water, ammonium ions, and anions that can form salts with the ammonium ions,
A thermosetting binder composition having a pH of 7 to 10.
[2] The thermosetting binder composition according to [1] above, wherein the proportion of the anion to the total of the non-reducing sugar and the phenol is 4 to 20% by mass.
[3] The thermosetting binder composition of [1] or [2] above, wherein the proportion of the phenol relative to the total of the non-reducing sugar and the phenol is 0.1 to 20% by mass.
[4] The thermosetting binder composition according to any one of [1] to [3] above, which does not contain a raw material containing formaldehyde.
[5] The thermosetting binder composition according to any one of [1] to [4], wherein the non-reducing sugar contains at least one selected from the group consisting of sucrose and trehalose.
[6] The thermosetting binder composition according to any one of [1] to [5], wherein the anion contains at least one selected from the group consisting of phosphate ions and phenolsulfonate ions.
[7] The thermosetting binder composition according to any one of [1] to [6], wherein the phenol is soluble in a 25% by mass ammonia aqueous solution.
[8] The thermosetting binder composition according to any one of [1] to [7], wherein the phenol contains at least one selected from the group consisting of resorcinol and tannin.
[9] An inorganic fiber product comprising a molded body formed by bonding inorganic fibers with a binder,
An inorganic fiber product, wherein the binder is a cured product of the thermosetting binder composition according to any one of [1] to [8].
[10] The inorganic fiber product of [9] above, wherein the inorganic fiber is glass wool or rock wool.

According to one aspect of the present invention, it is possible to provide a thermosetting binder composition that exhibits good binder performance without using raw materials containing formaldehyde and does not easily corrode metals, and an inorganic fiber product using the same. .

3 is a graph showing the results of Test Example 1. It is a graph showing the results of Test Example 7 (relationship between tannin ratio and tensile strength in binder composition).

<Thermosetting binder composition>
A thermosetting binder composition (hereinafter also simply referred to as a "binder composition") according to one embodiment of the present invention comprises non-reducing sugars, phenols, water, ammonium ions (NH ₄ ⁺ ), and the Contains ammonium ions and anions that can form salts.
Further, the pH of the binder composition of this embodiment is 7 to 10.

[Non-reducing sugar]
Non-reducing sugars are carbohydrates other than reducing sugars. Non-reducing sugars include, but are not limited to, sucrose, trehalose, raffinose, and the like. These non-reducing sugars may be used alone or in combination of two or more.
The non-reducing sugar is preferably at least one selected from the group consisting of sucrose and trehalose from the viewpoint of stability under alkaline conditions, and sucrose is particularly preferred from the viewpoint of ease of heat curing.

[Phenols]
Phenols are aromatic hydroxy compounds in which the hydrogen atoms of the aromatic hydrocarbon nucleus are replaced with hydroxy groups. Phenols, together with non-reducing sugars, form the skeleton of the cured product. Note that phenol resin is not included in phenols.
Examples of phenols include phenols derived from plant materials, phenols derived from fossil fuels, and the like.
Phenols derived from plant materials include flavonoid tannins, catechins, anthocyanins, rutin, isoflavones, phenolic acids such as chlorogenic acid, ellagic acid, lignans, curcumin, coumarin, polyphenols such as lignin, cardanol, cashew nut shell liquid, etc. Can be mentioned.
Fossil fuel phenols include phenol, cresol, xylenol, trimethylphenol, ethylphenol, propylphenol, butylphenol, butylcresol, phenylphenol, cumylphenol, methoxyphenol, bromophenol, bisphenol A, bisphenol F, bisphenol S, Examples include catechol, resorcinol, hydroquinone, pyrogallol, phloroglucinol, and the like.
These phenols may be used alone or in combination of two or more.
Among these, polyhydric phenols (phenols having two or more hydroxyl groups) are preferred because they have better binder performance.

It is preferable that the phenol is soluble in a 25% by mass ammonia aqueous solution. If the phenol is soluble in the 25% by mass ammonia aqueous solution, the phenol will dissolve in the binder composition and will be more easily mixed with the non-reducing sugar, resulting in better binder performance.
"Soluble in a 25% by mass ammonia aqueous solution" indicates that the solubility in a 25% by mass ammonia aqueous solution is 2 g/100 mL or more at 20°C.
Examples of phenols soluble in a 25% by mass ammonia aqueous solution include tannin, phenol, cresol, catechol, resorcinol, hydroquinone, pyrogallol, phloroglucinol, and the like.

As the phenols, polyhydric phenols that are soluble in a 25% by mass ammonia aqueous solution are more preferable because they have better binder performance, and at least one kind selected from the group consisting of tannins and resorcinol is more preferable because they have better binder performance. Tannins are particularly preferred because they are superior, inexpensive, and environmentally friendly.

[anion]
The anion capable of forming a salt with ammonium ion functions as an acid catalyst in the curing reaction of the binder composition of this embodiment. The curing reaction will be explained in detail later.
The anion may be any anion as long as it can form a salt with ammonium ion, and includes inorganic acid anions, organic acid anions, and the like. Examples of inorganic acid anions include sulfate ions, phosphate ions, and the like. Examples of the organic acid anion include phenolsulfonate ion, citrate ion, and the like. These anions may be used alone or in combination of two or more.
In terms of practicality, the anion is preferably at least one selected from the group consisting of phosphate ions and phenolsulfonate ions, and more preferably phosphate ions or a mixture of phosphate ions and phenolsulfonate ions. .
Note that under the condition of pH 7 to 8, phosphate ion mainly exists in the state of HPO ₄ ^2- , and under the condition of pH 8 to 10, it mainly exists in the state of PO ₄ ^3- .

[Other ingredients]
The binder composition may further contain components other than the above-mentioned non-reducing sugars, phenols, ammonium ions, and anions, as necessary, within a range that does not impair the effects of the present invention.
Other components can be selected and used as appropriate from among those known as components that can be incorporated into thermosetting binder compositions used in the production of inorganic fiber products, etc., such as carbohydrates other than non-reducing sugars, ammonium Basic compounds other than ions (organic amines, etc.), surfactants, silane coupling agents, water repellents, dust prevention oils, hardening modifiers, hardening accelerators, urea, melamine, furfural, furfuryl alcohol, etc. It will be done. Any one of these may be used alone or two or more may be used in combination.

Examples of the surfactant include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. Examples of the anionic surfactant include linear sodium alkylbenzene sulfonate, sodium alkyl sulfate, sodium alkyl ether sulfate, sodium alpha olefin sulfonate, sodium alkyl sulfonate, sodium fatty acid, potassium fatty acid, and the like. Examples of the cationic surfactant include alkyltrimethylammonium salts, dialkyldimethylammonium salts, and the like. Examples of amphoteric surfactants include sodium alkylamino fatty acids, alkyl betaines, and alkyl amine oxides. Examples of the nonionic surfactant include sucrose fatty acid ester sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, fatty acid alkanolamide, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, alkyl polyglucoside, and the like. These surfactants may be used alone or in combination of two or more.

Examples of silane coupling agents include amino group-containing silane coupling agents, epoxy group-containing silane coupling agents, vinyl group-containing silane coupling agents, methacryloyl group-containing silane coupling agents, acryloyl group-containing silane coupling agents, and ureido group-containing silane coupling agents. Examples include silane coupling agents, isocyanate group-containing silane coupling agents, and the like. As the amino group-containing silane coupling agent, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxy Silane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2 Examples include hydrochloride of -aminoethyl-3-aminopropyltrimethoxysilane. Epoxy group-containing silane coupling agents include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxy Examples include propylmethyldiethoxysilane and 3-glycidoxypropyltriethoxysilane. Examples of the vinyl group-containing silane coupling agent include vinyltriethoxysilane. Examples of the methacryloyl group-containing silane coupling agent include 3-methacryloxypropyltrimethoxysilane and the like. Examples of the acryloyl group-containing silane coupling agent include 3-acryloxypropyltrimethoxysilane. Examples of the ureido group-containing silane coupling agent include 3-ureidopropyltriethoxysilane and the like. Examples of the isocyanate group-containing silane coupling agent include 3-isocyanatepropyltriethoxysilane and the like. These silane coupling agents may be used alone or in combination of two or more.

Examples of the water repellent include silicone water repellents, fluorine water repellents, hydrocarbon water repellents, and the like. These water repellents may be used alone or in combination of two or more.
Examples of the dust prevention oil include mineral oil-based oil emulsions.
The curing modifier is preferably a water-soluble high boiling point solvent, such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, 1,4-butylene glycol, glycerin, diglycerin (also referred to as diglycerol), or polyester. Examples include glycerin and the like. These curing regulators may be used alone or in combination of two or more.
As the curing accelerator, phosphoric acid compounds are preferred. Examples of the phosphoric acid compound include alkali metal hypophosphites, alkali metal phosphites, alkali metal polyphosphates, alkali metal hydrogen phosphates, alkyl phosphates, and the like. As the alkali metal salt, sodium salt or potassium salt is preferable, and examples thereof include sodium hypophosphite, sodium phosphite, and the like.

The binder composition of this embodiment can exhibit good binder performance without using raw materials containing formaldehyde. Therefore, it is preferable that the binder composition of this embodiment does not contain a raw material containing formaldehyde (for example, formaldehyde or a phenol resin obtained by reacting phenols with formaldehyde). If the binder composition does not contain formaldehyde-containing raw materials, the generation of odors during the production of inorganic fiber products can be further reduced.

[composition]
In the binder composition of this embodiment, the total content of non-reducing sugars and phenols is preferably 75 to 99% by mass, and 80 to 95% by mass, based on the entire solid content (100% by mass) of the binder composition. is more preferable, and even more preferably 85 to 90% by mass. Non-reducing sugars and phenols are components that form the skeleton of the cured product. If the total content of non-reducing sugars and phenols is equal to or higher than the lower limit, the binder performance will be efficiently exhibited, and the resulting inorganic fiber product will have good properties such as tensile strength. On the other hand, if the total content of non-reducing sugars and phenols is below the above-mentioned upper limit, when molding an inorganic fiber product, curing is completed within predetermined molding conditions (temperature, time) and required. It is easy to achieve the desired performance.

The ratio of phenols to the total of non-reducing sugars and phenols (100% by mass) is preferably 0.1 to 20% by mass, more preferably 1 to 20% by mass, even more preferably 2 to 15% by mass, and 7% by mass. Particularly preferred is .5 to 12.5% by weight. If the proportion of phenols is within the above range, the binder performance will be better, and the obtained inorganic fiber products will have better properties such as tensile strength.

The water content is set depending on the solid content concentration of the binder composition.
The solid content concentration of the binder composition can be appropriately set in consideration of the solubility of non-reducing sugars and phenols, the usage form of the binder composition, etc. It may be %.

The ammonium ions react with reducing sugars produced after hydrolysis of non-reducing sugars in the curing reaction of the binder composition. Additionally, the pH of the binder composition is adjusted.
The content of ammonium ions is set depending on the type and content of anions so that the pH of the binder composition is 7 to 10 (further preferred range described below).
For example, when the anion is a phosphate ion, the content of ammonium ions is preferably 20 to 40% by mass, more preferably 25 to 35% by mass, based on the total of phosphate ions and ammonium ions.
When the anion is a mixture of phosphate ions and phenolsulfonate ions, the content of ammonium ions is preferably 10 to 30% by mass, based on the total of phosphate ions, phenolsulfonate ions, and ammonium ions, and 15% by mass. ~25% by mass is more preferred.

The ratio of anions to the total of non-reducing sugars and phenols (100% by mass) is preferably 4 to 20% by mass, more preferably 5 to 17.5% by mass, and even more preferably 6 to 15% by mass. If the proportion of anions is at least the lower limit, curing is completed within predetermined molding conditions (temperature, time) when molding an inorganic fiber product, and required performance is easily achieved. On the other hand, if the proportion of anions is below the above-mentioned upper limit, the binder performance will be efficiently exhibited, and the obtained inorganic fiber products will have good properties such as tensile strength.

The content of other components may be, for example, 0 to 10% by mass based on the total solid content of the binder.
When the binder composition contains reducing sugar, the pH of the binder composition may decrease over time. From the viewpoint of suppressing pH decrease over time, the content of reducing sugar is preferably 5% by mass or less, particularly preferably 0% by mass, based on the entire solid content of the binder. That is, it is particularly preferable that the binder composition of this embodiment does not contain reducing sugars.

The contents of non-reducing sugars, phenols, ammonium ions, anions, and other components are based on solid content.
"Solid content" is the total of components other than water.
“Solid content concentration” is a value calculated by {(total mass−mass of water)/total mass}×100 (mass%).
For example, in the case of non-reducing sugars, when preparing a binder composition, if powdered non-reducing sugar is used, all of it is handled as solid content, and when a non-reducing sugar aqueous solution is used, it is treated as solid content (non-reducing sugar). Sugar) and water are handled separately.

[pH]
The pH of the binder composition of this embodiment is 7 to 10, preferably 7 to 9. If the pH is above the lower limit, metals such as iron are less likely to corrode. In addition, phenols are easily dissolved, and binder performance (tensile strength, etc.) is better. If the pH is below the upper limit, the gelation time of the binder composition can be shortened sufficiently for practical purposes.
pH is the value at 25°C.

[Method for manufacturing binder composition]
The binder composition of this embodiment can be prepared by mixing non-reducing sugars, phenols, water, ammonium ions, anions, and other components as necessary.
Each component may be mixed all at once or sequentially.
To give an example of a method for producing a binder composition, first, an acid corresponding to an anion (such as phosphoric acid) or an ammonium salt thereof is dissolved in water to obtain an aqueous solution containing an anion. An ammonia aqueous solution is added to the resulting aqueous solution to adjust the pH to 7-10. Phenols are dissolved in a pH-adjusted aqueous solution, and the resulting solution and non-reducing sugar (powder or aqueous solution) are mixed. Add water as necessary to adjust the solid content concentration. A binder composition is thus obtained.

The binder composition of this embodiment has curability that can be cured by heating.
The thermosetting mechanism of the binder composition of this embodiment is considered to be a mechanism similar to caramelization. When the binder composition is heated, first, non-reducing sugars are hydrolyzed to become reducing sugars, and the reducing sugars react with ammonium ions to become glucosylamines. 1-amino-1-deoxy-2-ketose is then formed with ring opening. This is generally referred to as Amadori metastasis. Subsequently, under the influence of anion (acid catalyst) and heating, the ring is closed with dehydration to produce hydroxymethylfurfural (hereinafter referred to as HMF). HMF is a thermally unstable compound, and the generated HMF reacts with other HMF and phenols under continuous heating and with further dehydration. As this reaction progresses, curing progresses and is eventually completed. It is assumed that the resulting cured product has a caramel-like structure in which a phenolic skeleton is introduced into a part of the structure.
It is thought that water is the only by-product produced in the above reaction. Therefore, when the binder composition of this embodiment is used in the manufacturing process of inorganic fiber products, etc., the gas generated during curing of the binder composition is considered to be mostly only water vapor.

<Inorganic fiber products>
An inorganic fiber product according to one aspect of the present invention includes a molded article formed by bonding inorganic fibers with a binder. This binder is a cured product of the binder composition described above.
The inorganic fibers are not particularly limited, and include, for example, glass wool, rock wool, ceramic fibers, and the like. Any one of these may be used alone or two or more may be used in combination. As the inorganic fiber, glass wool or rock wool is preferable in terms of versatility and heat insulation performance.
The inorganic fiber product may be made of the molded body, or may further include other members other than the molded body. Examples of the other members include a skin material for packaging.
Inorganic fiber products can be used, for example, as heat insulating materials, sound absorbing materials, and various other molded products (automobile roofs, bonnet liners, etc.).

[Method for manufacturing inorganic fiber products]
Inorganic fiber products can be manufactured by a manufacturing method that includes a step of molding inorganic fibers using the binder composition described above to obtain a molded article.
In the production of inorganic fiber products, known methods conventionally used in the production of inorganic fiber products can be used, except for using the above-mentioned binder composition as a binder.
As an example of a method for manufacturing inorganic fiber products, there is a step of attaching a binder composition to inorganic fibers (hereinafter referred to as an adhesion step), and a step of accumulating the inorganic fibers to which the binder composition has been attached and forming a structure corresponding to the inorganic fiber product to be manufactured. An example of a method is to sequentially perform a step of forming a shaped aggregate, then heating the aggregate and curing the binder composition to obtain a molded body (hereinafter referred to as a forming process). Each step will be explained in more detail below.

(Adhesion process)
The inorganic fibers used in the attachment step include those mentioned above.
The fiber length and fiber diameter of the inorganic fibers may be appropriately set depending on the inorganic fiber product to be manufactured, and are not particularly limited. Usually, those having a fiber diameter in the range of 3 to 10 μm are used.
Commercially available inorganic fibers may be used, or those produced by known methods may be used as they are. Inorganic fibers are generally produced by fiberizing raw materials (waste glass, basalt, iron furnace slag, etc.). Examples of the fiberization method include a flame method and a centrifugal method. Fiberization by these various methods can be performed using corresponding fiberization equipment.

Examples of methods for attaching the binder composition to the inorganic fibers include a method of spraying the binder composition onto the inorganic fibers using a spray device, a method of impregnating the inorganic fibers with the binder composition, etc. A method may also be used.
The amount of the binder composition to be attached to the inorganic fibers is not particularly limited, but is usually in the range of 0.5 to 20% by mass, based on the nonvolatile content of the binder composition, based on the inorganic fibers (100% by mass). This amount affects the physical properties (mechanical strength, etc.) of the molded product obtained. For example, the larger the amount of the binder composition attached to the inorganic fibers, the higher the mechanical strength of the resulting molded article tends to be.
"Nonvolatile content" refers to a value measured in accordance with the provisions of JIS K6910 5.6.

(molding process)
Next, the inorganic fibers to which the binder composition has been attached are aggregated to form an aggregate having a shape corresponding to the inorganic fiber product to be manufactured, and then the aggregate is heated to cure the binder composition.
The molding process can be performed by a known method. For example, when manufacturing a plate-shaped inorganic fiber product, inorganic fibers are deposited on a conveyor, and this deposit is compressed by pressing from above and below the conveyor to form an aggregate. A plate-shaped molded body is obtained by sending the aggregate to a heating furnace (hardening furnace) and heating to harden the binder composition.
The amount of inorganic fiber used (the amount of inorganic fiber deposited on the conveyor) and compression conditions are set depending on the thickness, bulk density, etc. of the inorganic fiber product to be manufactured.
The heating conditions (heating temperature, heating time) for the aggregate are not particularly limited as long as the binder composition in the aggregate is cured, but the heating temperature is preferably within the range of 180 to 270°C. If the temperature is less than 180°C, curing may be insufficient and mechanical strength may be insufficient.
If the temperature exceeds 270°C, there is a risk that the binder composition will decompose, resulting in a decrease in yield and mechanical strength. The heating time varies depending on the size of the aggregate, heating temperature, etc., and is not particularly limited.

The obtained molded product may be used as an inorganic fiber product as it is, or may be further subjected to treatments such as cutting and packaging with a skin material, if necessary.

EXAMPLES Below, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the examples. Example 20 is a reference example.
In each of the following examples, "parts" and "%" indicate "parts by mass" and "% by mass," respectively, unless otherwise specified.
The measurement methods and materials used in each example described below are shown below.

<pH>
The pH was measured at a measurement temperature of 25° C. according to the provisions of JIS K6910 5.4.

<Gelification time>
The gelation time of the binder composition was measured at a measurement temperature of 150° C. according to the provisions of JIS K6910 5.14.1 (gelation time method A).

<Tensile strength>
The tensile strength was measured according to the following procedure.
12 g of ion-exchanged water was added to 18 g of the binder composition adjusted to a solid content concentration of 50% to prepare a binder solution with a solid content concentration of 30%.
A glass filter paper (manufactured by Whatman) cut into 90 mm x 25 mm was impregnated with the binder solution, excess binder solution was removed on paper waste (Kim Towel, manufactured by Nippon Paper Industries), and the paper was dried in a dryer at 100°C for 30 minutes. After that, it was cured at 190°C for 15 minutes. The amount of binder attached is about 60±2%.
Both sides of the cured test piece were cut to obtain a 90 mm x 20 mm test piece. The top and bottom 20 mm of this test piece were held in the chuck of a tensile tester, and the test piece was pulled at a head speed of 5 mm/min to measure its strength (N). The tensile strength was calculated from the measurement results using the following formula.
Tensile strength (MPa) = measured value (N)/6 (mm ² )
The denominator on the right side of the above equation is the cross-sectional area of the test piece (20 mm x 0.3 mm).
The tensile strength was determined for a total of five test pieces, and the average value was calculated.

<Materials used>
Sucrose: Powder, manufactured by Fujifilm Wako Pure Chemical Industries, reagent, special grade.
Sucrose aqueous solution: solid content concentration 67%, prepared by dissolving the above sucrose in ion exchange water.
Isomerized high fructose sugar: liquid, manufactured by Gun-ei Chemical Industry Co., Ltd., 75FG, solid content concentration 75%, contains glucose at a ratio of 45% and fructose at a ratio of 42% to the total carbohydrate.
Trehalose dihydrate: Powder, manufactured by Hayashibara.
Tannin (1): Powder, UCL Company Pty Ltd. , manufactured by Mimosa NT.
Tannin (2): powder, NTE Company Pty Ltd. , manufactured by Bontite 241.
Tannin (3): Powder, UCL Company Pty Ltd. , manufactured by ME Powder.
Tannin (4): Powder, TUPAPIN NTO.
Tannin (5): Powder, Silvateam S. p. a. Manufactured by FINTAN 737.
Resorcinol: Powder, manufactured by Sumitomo Chemical.
Triammonium phosphate: Manufactured by Fujifilm Wako Pure Chemical Industries, reagent, special grade.
Ammonium dihydrogen phosphate: Manufactured by Fujifilm Wako Pure Chemical Industries, reagent, special grade.
85% phosphoric acid aqueous solution: manufactured by Katakura Co-op Agri.
65% phenolsulfonic acid aqueous solution: manufactured by Nihon Kagaku Sangyo Co., Ltd.
25% ammonia aqueous solution: manufactured by Mitsubishi Chemical Corporation.

<Test Example 1>
This test was conducted to evaluate the effect of carbohydrates on the pH of the binder composition.

Binder compositions (Example 1, Comparative Example 1) having the compositions shown in Table 1 were prepared according to the following procedure. The composition shown in Table 1 shows the mass (g) of each component per 100 g of the binder composition.
First, 3.6 g of an 85% phosphoric acid aqueous solution was dissolved in 9.2 g of ion-exchanged water. A 25% ammonia aqueous solution was added thereto while checking the pH (by inserting the electrode of a pH meter and stirring), and finally the pH was adjusted to 9.0. Next, 2.2 g of tannin (1) was added and dissolved. Next, 64.5 g of a sucrose aqueous solution with a solid content concentration of 67% (Example 1) or 57.6 g of isomerized sugar syrup with a solid content concentration of 75% (Comparative Example 1) were added and uniformly dissolved. Thereafter, ion-exchanged water was added so that the total amount of the binder composition was finally 100 g to obtain a binder composition. Table 1 shows the pH (initial pH) of the obtained binder composition.

The resulting binder composition was stored at 25°C. The pH of the binder composition was measured 1 day, 3 days, 7 days, and 14 days after the start of storage. The measurement results are shown in Figure 1.
As shown in FIG. 1, the pH of the binder composition of Comparative Example 1 in which the carbohydrate was high fructose sugar (reducing sugar) decreased over time. In contrast, the binder composition of Example 1, in which the carbohydrate was sucrose (non-reducing sugar), maintained its initial pH.

<Test Example 2>
This test was conducted to evaluate the relationship between pH and metal (iron) corrosivity.

(1)
Solutions having the compositions shown in Table 2 (Comparative Examples 2 to 6) were prepared according to the following procedure. The composition shown in Table 2 shows the mass (g) of each component per 50 g of solution.
Sucrose, ammonium dihydrogen phosphate or triammonium phosphate, and water were mixed according to the composition shown in Table 2 to obtain a solution. Table 2 shows the pH of the obtained solution (initial solution pH).
50 g of each solution was placed in a transparent wide-mouth bottle with a lid (made of polypropylene, capacity 200 mL), and an iron nail (a round nail with a length of 35 mm, degreased with acetone) was placed therein, and the bottle was allowed to stand at 25° C. for 24 hours. Thereafter, the appearance of the iron nail in the solution was visually observed and evaluated based on the following criteria. The results are shown in Table 2.
○: No change.
×: Black rust or red rust occurred.
Note that black rust is an oxide film formed on the surface of iron, and is represented by the chemical formula Fe ₃ O ₄ . Black rust does not occur naturally on ordinary iron.

<Test Example 3>
Similar to Test Example 2, this test was conducted to evaluate the relationship between pH and metal (iron) corrosivity.

Ammonium dihydrogen phosphate was dissolved in ion-exchanged water to prepare a 10% aqueous ammonium dihydrogen phosphate solution. A 25% ammonia aqueous solution was added to a 10% aqueous ammonium dihydrogen phosphate solution so as to have the pH shown in Table 3 to obtain a solution.
50 g of each solution was placed in a transparent wide-mouth bottle with a lid (made of polypropylene, capacity 200 mL), and an iron nail (a round nail with a length of 35 mm, degreased with acetone) was placed therein, and the bottle was allowed to stand at 25° C. for 24 hours. Thereafter, the appearance of the iron nail in the solution was visually observed. The results are shown in Table 3.

From the results of Test Examples 2 and 3, it can be determined that if the pH is 7 or higher, it is difficult to corrode metal (iron).

<Test Example 4>
This test was conducted to evaluate the relationship between pH and tannin solubility.

Ammonium dihydrogen phosphate was dissolved in ion-exchanged water to prepare a 10% aqueous ammonium dihydrogen phosphate solution. A 25% ammonia aqueous solution was added to a 10% aqueous ammonium dihydrogen phosphate solution so as to have the pH shown in Table 4 to obtain a solution.
0.5 g of tannin (2) was added to 10 g of each solution and stirred well. After 1 hour, the solution was visually observed, and the solubility of tannin (2) was evaluated using the following criteria. The results are shown in Table 4.
○: Completely dissolved.
×: Insoluble matter was present.

<Test Example 5>
This test was conducted to evaluate the solubility of phenols in water or alkaline water.

0.5 g of the phenols shown in Table 5 was added to 10 g of water (ion-exchanged water) or alkaline water (25% ammonia aqueous solution), and the mixture was thoroughly stirred. After 1 hour, the solution was visually observed, and the solubility of phenols was evaluated using the same criteria as in Test Example 4. The results are shown in Table 5.

<Test Example 6>
This test was conducted to evaluate the effect of pH and phenols on binder properties.

Binder compositions (Comparative Examples 7 to 8, Examples 2 to 7) having the compositions shown in Table 6 were prepared according to the following procedure. The composition shown in Table 6 shows the mass (g) of each component per 100 g of the binder composition.
First, 4.6 g of an 85% phosphoric acid aqueous solution was dissolved in 9.2 g of ion-exchanged water. While checking the pH (inserting the electrode of a pH meter and stirring), 25% ammonia aqueous solution was added, and the final pH was adjusted to 5.0 (Comparative Example 7) or 9.0 (Comparative Example). 8, Examples 2 to 7). Next, for Examples 2 to 7, 4.5 g of the phenols shown in Table 6 (any of tannins (1) to (5) and resorcinol) were added and dissolved. Next, 67.9 g (Comparative Examples 7-8) or 61.3 g (Examples 2-7) of a sucrose aqueous solution with a solid content concentration of 67% was added and uniformly dissolved. Thereafter, ion-exchanged water was added so that the total amount of the binder composition was finally 100 g to obtain a binder composition.
Table 6 shows the pH of the obtained binder composition (binder pH). Moreover, the gelation time and tensile strength of the obtained binder composition were evaluated. The results are shown in Table 6.

A comparison between Comparative Example 7 and Comparative Example 8 shows that tensile strength is improved by setting the binder pH to 7 to 10.
A comparison between Comparative Example 8 and Examples 2 to 7 shows that when the binder composition contains phenols, the tensile strength is improved and the gelation time is shortened.

<Test Example 7>
This test was conducted to evaluate the effect of the ratio of phenols to the sum of carbohydrates and phenols on binder properties.

Binder compositions (Comparative Example 9, Examples 8 to 12) having the composition shown in Table 7 were prepared according to the following procedure. The composition shown in Table 7 shows the mass (g) of each component per 100 g of the binder composition.
First, 5.5 g of an 85% phosphoric acid aqueous solution was dissolved in 13.2 g of ion-exchanged water. While checking the pH (by inserting the electrode of a pH meter and stirring), a 25% ammonia aqueous solution was added, and the pH was finally adjusted to 8.0. Next, for Examples 8 to 12, tannin (2) was added and dissolved to have the composition shown in Table 7. Next, an aqueous sucrose solution having a solid content concentration of 67% was added so as to have the composition shown in Table 7, and was uniformly dissolved. In Examples 8 to 12, the total amount of sucrose (solid content) and tannin (2) was 43.5 g. Thereafter, ion-exchanged water was added so that the total amount of the binder composition was finally 100 g to obtain a binder composition.
Table 7 shows the pH (binder pH) and tannin ratio (%) of the obtained binder composition. The tannin ratio is the ratio of tannin (2) to the total (100%) of sucrose (solid content) and tannin (2). Moreover, the gelation time and tensile strength of the obtained binder composition were evaluated. The results are shown in Table 7. Further, FIG. 2 shows a graph in which the horizontal axis represents the tannin ratio (%) and the vertical axis represents the tensile strength (MPa) in Comparative Example 9 and Examples 8 to 12.

A comparison between Comparative Example 9 and Examples 8 to 12 shows that when the binder composition contains phenols, the tensile strength is improved and the gelation time is shortened.

<Test Example 8>
This test was conducted to evaluate the effects of pH, phenols and anions on binder properties.

Binder compositions (Comparative Examples 10 to 11, Examples 13 to 18) having the compositions shown in Table 8 were prepared according to the following procedure. The composition shown in Table 8 shows the mass (g) of each component per 100 g of the binder composition.
First, 2.2 g of an 85% phosphoric acid aqueous solution and 6.0 g of a 65% phenolsulfonic acid aqueous solution were dissolved in 10.2 g of ion-exchanged water. While checking the pH (inserting the electrode of a pH meter and stirring), 25% ammonia aqueous solution was added, and the final pH was adjusted to 5.0 (Comparative Example 10) or 9.0 (Comparative Example). 11, Examples 13 to 18). Next, for Examples 13 to 18, 2.2 g of the phenols shown in Table 8 (any of tannins (1) to (5) and resorcinol) were added and dissolved. Next, 64.9 g (Comparative Examples 10-11) or 61.6 g (Examples 13-18) of a sucrose aqueous solution with a solid content concentration of 67% was added and uniformly dissolved. Thereafter, ion-exchanged water was added so that the total amount of the binder composition was finally 100 g to obtain a binder composition.
Table 8 shows the pH of the obtained binder composition (binder pH). Moreover, the gelation time and tensile strength of the obtained binder composition were evaluated. The results are shown in Table 8.

From the above results, even when phosphate ions and phenolsulfonate ions are used together as anions, by setting the binder pH to 7 to 10, as in Test Example 6 using only phosphate ions as anions, It can be seen that the tensile strength is improved and that the inclusion of phenols in the binder composition improves the tensile strength and shortens the gelation time.

<Test Example 9>
This test was conducted to evaluate the effects of pH, carbohydrates and phenols on binder properties.

Binder compositions (Example 19, Comparative Example 12) were prepared in the same manner as in Example 2, except that the amounts of each material added were changed so as to have the compositions shown in Table 9.
A binder composition (Example 20) was prepared in the same manner as in Example 19, except that 47.7 g of powdered trehalose dihydrate (43.2 g in terms of anhydride) was used instead of the sucrose aqueous solution with a solid content concentration of 67%. ) was prepared.
Binder compositions (Comparative Examples 13 to 14) were prepared in the same manner as Comparative Example 7, except that the amounts of each material added were changed so as to have the compositions shown in Table 9.
The amount of 85% phosphoric acid aqueous solution added was 4.6 g in all Examples 19-20 and Comparative Examples 12-14.
Table 9 shows the pH of the obtained binder composition (binder pH). Moreover, the gelation time and tensile strength of the obtained binder composition were evaluated. The results are shown in Table 9.

Comparing Example 19 and Comparative Example 12, which had different pH values, Example 19, which had a pH of 7 or more, had better tensile strength than Comparative Example 12, which had a pH of less than 7. Although the gelation time of Example 19 was slightly longer than that of Comparative Example 12, it was a practically sufficient value.
Comparing Comparative Example 12 and Comparative Example 13, which differ in the presence or absence of tannin (1), shows that although the pH is about the same, Comparative Example 12, which contains tannin (1), has superior tensile strength and gelation time. It was getting shorter. A similar tendency was confirmed in a comparison between Example 19 and Comparative Example 14.

The thermosetting binder composition of the present invention can exhibit good binder performance without using raw materials containing formaldehyde. It also does not corrode metal easily.

The thermosetting binder composition of the present invention is useful for producing inorganic fiber products. However, the uses of the binder composition of the present invention are not limited thereto, and can be used in various uses where thermosetting binders such as phenolic resin binders have conventionally been used. Examples include applications for casting, friction materials, grindstones, filter paper, molding materials, plywood processing, decorative boards, and laminated boards.

Claims (8)

Contains non-reducing sugars, phenols, water, ammonium ions, and anions that can form salts with the ammonium ions, and does not contain reducing sugars,
the non-reducing sugar is sucrose,
The anion includes at least one selected from the group consisting of phosphate ions and phenolsulfonate ions,
A thermosetting binder composition having a pH of 7 to 10. The thermosetting binder composition according to claim 1, wherein the proportion of the anion to the total of the non-reducing sugar and the phenol is 4 to 20% by mass. The thermosetting binder composition according to claim 1 or 2, wherein the ratio of the phenol to the total of the non-reducing sugar and the phenol is 0.1 to 20% by mass. The thermosetting binder composition according to any one of claims 1 to 3, which does not contain a raw material containing formaldehyde. The thermosetting binder composition according to any one of claims 1 to 4 , wherein the phenol is soluble in a 25% by mass ammonia aqueous solution. The thermosetting binder composition according to any one of claims 1 to 5 , wherein the phenol contains at least one selected from the group consisting of resorcinol and tannin. An inorganic fiber product comprising a molded body formed by bonding inorganic fibers with a binder,
An inorganic fiber product, wherein the binder is a cured product of the thermosetting binder composition according to any one of claims 1 to 6 . The inorganic fiber product according to claim 7 , wherein the inorganic fiber is glass wool or rock wool.

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