Manufacturing method of aqueous binder for inorganic fiber heat insulating and sound absorbing material

Abstract

An object of the present invention is to provide a method for producing an aqueous binder for an inorganic fiber thermal insulation sound-absorbing material, which reduces the amount of ammonia gas emitted during the production of the inorganic fiber thermal insulation sound-absorbing material. [Solution] A method for producing an aqueous binder for inorganic fiber thermal insulation sound-absorbing materials, the method for producing an aqueous binder for inorganic fiber thermal insulation sound-absorbing materials, includes an acid addition step of adding an acid to a phenol-formaldehyde resin composition containing a resol-type phenol-formaldehyde resin and an amine compound, and a water addition step of adding water after the acid addition step to adjust the solids concentration, wherein the pH of the aqueous binder for inorganic fiber thermal insulation sound-absorbing materials is 8.1 to 9.4.

Description

[Technical field]

[0001] The present invention relates to a method for producing an aqueous binder for an inorganic fiber heat insulating and sound absorbing material. [Background technology]

[0002] Inorganic fiber heat insulating sound absorbing materials such as glass wool and rock wool are generally manufactured by attaching a binder to inorganic fibers and then curing the binder. As the binder, a binder mainly composed of phenol formaldehyde resin obtained by reacting phenols with formaldehydes (hereinafter also referred to as "phenolic resin binder") is widely used because it is relatively inexpensive and can produce inorganic fiber heat insulating sound absorbing materials with excellent performance such as mechanical strength. However, when a phenolic resin-based binder is used, there is a problem that formaldehyde volatilizes during the manufacturing process of the inorganic fiber heat insulating sound absorbing material, and that formaldehyde is emitted from the obtained inorganic fiber heat insulating sound absorbing material product. Formaldehyde is a substance that has adverse effects on the human body, and for example, aldehyde emitted from building materials is considered to be one of the substances that cause sick house syndrome.

[0003] As a measure to deal with the problem of formaldehyde volatilization during the manufacturing process of inorganic fiber heat insulation and sound absorbing materials (such as the binder application process), phenol formaldehyde resin is modified with urea. In this case, the free formaldehyde in the phenol formaldehyde resin is captured by the urea introduced into the phenol formaldehyde resin, reducing the amount of formaldehyde volatilization during the manufacturing process and improving the working environment. In addition, to address the problem of formaldehyde emitting from inorganic fiber heat insulating and sound absorbing material products, a formaldehyde scavenger such as adipic acid dihydrazide is applied to the product. The formaldehyde scavenger reacts with the generated formaldehyde and fixes it, thereby reducing the amount of formaldehyde emitted. However, with the above-mentioned conventional methods, it is difficult to produce inorganic fiber products with low formaldehyde emission and good performance at low cost.

[0004] For example, the method of modifying phenol-formaldehyde resin with urea is effective in reducing the amount of formaldehyde emitted during the manufacturing process, but the amount of formaldehyde emitted from the resulting inorganic fiber heat insulating and sound absorbing material tends to increase. This is thought to be because the formaldehyde source is fixed in the product and remains as latent formaldehyde, and is re-released by hydrolysis, etc. In addition, there is a problem that the performance of the resulting inorganic fiber heat insulating and sound absorbing material product, such as water resistance, is lower when a binder using phenol-formaldehyde resin modified with urea is used compared to when a phenol-formaldehyde resin that is not modified with urea is used. In addition, although the use of formaldehyde scavengers is effective in reducing the amount of formaldehyde emitted, they may cause quality abnormalities such as discoloration and stickiness. In addition, since formaldehyde scavengers are more expensive than phenol-formaldehyde resins, the cost benefits of phenolic resin-based binders are lost when a large amount is used. In addition, since formaldehyde scavengers are usually added after the binder has hardened, this also leads to the complication of the process.

[0005] Under these circumstances, as a method for reducing the amount of free formaldehyde, a method has been proposed in which formaldehyde and phenol are reacted in the presence of a base catalyst to synthesize a resol-type phenol-formaldehyde resin, and then an amine is added at 50 to 65° C. to cause the unreacted formaldehyde and phenol to react with the amine to form a condensate (see Patent Document 1). Furthermore, in order to suppress the decrease in water dilutability of the binder due to the formation of a condensate of the unreacted formaldehyde and phenol with the amine, a method has been proposed in which a monoamine is added at less than 50° C. after synthesizing a resol-type phenol-formaldehyde resin to suppress the formation of the condensate while reducing the amount of formaldehyde emitted (see Patent Document 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 5450070 [Patent Document 2] Patent No. 7082893 [Patent Document 3] Patent No. 3784067 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the amine added by the above method decomposes and generates ammonia gas when it comes into contact with high-temperature inorganic fibers or is exposed to heat from the immediately preceding fiberization step during the binder application step in the manufacturing process of the inorganic fiber heat insulation and sound absorbing material. Since discharging a large amount of ammonia gas into the atmosphere is an environmental problem, an ammonia removal step such as acid washing of the exhaust gas is required, which increases costs. As a method for reducing the amount of ammonia gas released from the binder, for example, a method of neutralizing the ammonia in a phenol-formaldehyde resin formulation by adding a sugar compound has been proposed (see Patent Document 3), but the addition of the sugar compound may cause undesirable discoloration of the product.

[0008] Therefore, an object of the present invention is to provide a method for producing an aqueous binder for an inorganic fiber thermal insulation sound-absorbing material, which reduces the amount of ammonia gas emitted during the production of the inorganic fiber thermal insulation sound-absorbing material. [Means for solving the problem]

[0009] That is, the present invention is as follows. [1] A method for producing an aqueous binder for inorganic fiber heat insulating and sound absorbing materials, An acid addition step of adding an acid to a phenol-formaldehyde resin composition containing a resol-type phenol-formaldehyde resin and an amine compound. The acid is added while stirring the phenol-formaldehyde resin composition, and the temperature of the phenol-formaldehyde resin composition at the time of adding the acid is less than 50° C. and, a step of adding other components after the acid addition step, in which other components other than the resol-type phenol-formaldehyde resin and the amine compound are added; The above Other IngredientsAfter the addition step, a water addition step is performed to adjust the solid content concentration by adding water. Including, the resol-type phenol-formaldehyde resin is a resol-type phenol-formaldehyde resin synthesized by reacting a phenol with a formaldehyde using a catalyst containing a tertiary amine and / or a cyclic amine, the amine compound contains an amine compound other than an amine compound contained in a catalyst used in the synthesis of the resol-type phenol-formaldehyde resin, The other components include a curing accelerator and a silane coupling agent, The pH of the aqueous binder for inorganic fiber heat insulation and sound absorption materials is 8.1 to 9.4. A method for producing an aqueous binder for an inorganic fiber heat insulating and sound absorbing material, comprising: [2] The method for producing an aqueous binder for an inorganic fiber heat insulating and sound absorbing material according to [1], wherein the resol type phenol formaldehyde resin is a resol type phenol formaldehyde resin synthesized by reacting a phenol with a formaldehyde using a catalyst containing triethylamine. [3 ] before The amine compound other than the amine compound contained in the catalyst is monoethanolamine. 1 ] Or [2] A method for producing the aqueous binder for an inorganic fiber heat insulating and sound absorbing material according to claim 1. [ 4 ] The acid is sulfuric acid. 3 13. A method for producing an aqueous binder for an inorganic fiber heat insulating and sound absorbing material according to any one of claims 1 to 12. [ 5 ] The step of adding other ingredients a urea addition step of adding urea; Including Mm, [1]~[ 4 13. A method for producing an aqueous binder for an inorganic fiber heat insulating and sound absorbing material according to any one of claims 1 to 12. Effect of the Invention

[0010] According to the present invention, it is possible to provide a method for producing an aqueous binder for an inorganic fiber thermal insulation sound-absorbing material, in which the amount of ammonia gas emitted during the production of the inorganic fiber thermal insulation sound-absorbing material is reduced. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention (hereinafter, simply referred to as the present embodiment) will be described in detail. The present invention is not limited to the following embodiment, and can be modified in various ways within the scope of the present invention.

[0012] [Manufacturing method of aqueous binder for inorganic fiber heat insulating and sound absorbing material] The manufacturing method of the aqueous binder for inorganic fiber thermal insulation sound-absorbing material of this embodiment (hereinafter, also simply referred to as "aqueous binder") is characterized by including an acid addition step of adding an acid to a phenol-formaldehyde resin composition containing a resol-type phenol-formaldehyde resin and an amine compound, and a water addition step of adding water after the acid addition step to adjust the solids concentration. The method for producing the aqueous binder of the present embodiment may include, in addition to the acid addition step and the water addition step, other steps such as a resin synthesis step, an amine compound addition step, and a step of adding other components (such as a urea addition step) as necessary. In this specification, the aqueous binder refers to a composition that contains a phenol-formaldehyde resin composition containing an amine compound, an acid, and water for adjusting the concentration, and optionally contains other components such as urea, a curing accelerator, a silane coupling agent, a dust inhibitor, an anti-rust agent, a water repellent, and a colorant within a range that does not impair the effects of the present invention.

[0013] (Phenol formaldehyde resin composition) The phenol-formaldehyde resin composition to which acid is added in the acid addition step is not particularly limited as long as it contains a resol-type phenol-formaldehyde resin and an amine compound, and may be an industrially available commercially available product, or an industrially available commercially available resol-type phenol-formaldehyde resin to which an amine compound has been added, or, as described below, a synthesized resol-type phenol-formaldehyde resin to which an amine compound has been added, or a resol-type phenol-formaldehyde resin containing an amine compound obtained by synthesizing a resol-type phenol-formaldehyde resin using a catalyst containing an amine compound.

[0014] ((Resol-type phenol formaldehyde resin)) The resol-type phenol-formaldehyde resin contained in the phenol-formaldehyde resin composition may be a single type alone or a combination of two or more types. The weight average molecular weight of the resol type phenol formaldehyde resin is preferably from 150 to 800, more preferably from 150 to 600, and even more preferably from 150 to 400. When the weight average molecular weight of the resol type phenol formaldehyde resin is equal to or more than the lower limit of the above range, there is a tendency for the yield reduction and strength reduction of the aqueous binder in the inorganic fiber heat insulating sound absorbing material to be reduced, and when it is equal to or less than the upper limit of the above range, there is a tendency for the water dilution property and stability over time of the aqueous binder to be improved. In this specification, the weight average molecular weight of the resol-type phenol formaldehyde resin is a value measured by gel permeation chromatography (GPC) using polystyrene as a standard substance. In addition, in this specification, the water dilutability of the aqueous binder can be evaluated by the miscibility with water (mass%) measured for an aqueous binder with a solid content concentration of 40 mass% in accordance with the provisions of 5.5 of JIS K6910:2007. If the miscibility with water of the aqueous binder is 600 mass% or more, the water dilutability is good and it is possible to prevent the aqueous binder from precipitating in the binder liquid delivery piping, for example.

[0015] ((Amine Compounds)) As described above, the amine compound contained in the phenol-formaldehyde resin composition may be the catalyst used in synthesizing the resol-type phenol-formaldehyde resin, or may be one added after the synthesis of the resol-type phenol-formaldehyde resin, or may be both.

[0016] When the amine compound is a catalyst used in synthesizing a resol-type phenol-formaldehyde resin, examples of the amine compound include tertiary amines such as triethylamine, trimethylamine, and triethanolamine, and cyclic amines such as DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) and DBN (1,5-diazabicyclo[4.3.0]non-5-ene).

[0017] In addition, when the amine compound is added later to the resol-type phenol-formaldehyde resin, the amine compound is not particularly limited, and examples thereof include aliphatic amines, alicyclic amines, aromatic amines, and amine derivatives. Examples of the aliphatic amine include alkanolamines and alkylamines. Examples of the alkanolamine include (mono-, di-, or tri-)ethanolamine, (mono-, di-, or tri-)isopropanolamine, N-methylethanolamine, and N-methyldiethanolamine. Examples of the alkylamine include (mono-, di-, or tri-)methylamine, (mono-, di-, or tri-)ethylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexamethylenediamine, tetramethylethylenediamine, hexaethyleneheptamine, heptaethyleneoctamine, N-(3-aminopropyl)butane-1,4-diamine, N,N-di(3-aminopropyl)butane-1,4-diamine, and bishexamethylenetriamine. Examples of the alicyclic amine include piperidine, piperazine, pyrrolidine, morpholine, pyrrole, pyridine, pyrazole, imidazole, and oxazole. Examples of aromatic amines include aniline, aminophenol, and toluidine. Examples of the amine derivatives include ether amines and amino acids. Examples of the amino acids include glycine, glutamine, and glutamic acid. Among these, since the effect of reducing the amount of formaldehyde emitted from the aqueous binder is easily obtained, monoamines are preferred, aliphatic monoamines are more preferred, primary or secondary aliphatic monoamines are even more preferred, and monoethanolamine is particularly preferred.

[0018] The amine compound may be used alone or in combination of two or more kinds.

[0019] The molecular weight of the amine compound is preferably 300 or less, more preferably 200 or less, and even more preferably 150 or less, from the viewpoint of reducing formaldehyde emission from the aqueous binder and suppressing a decrease in water dilutability.

[0020] The content of the amine compound in the phenol-formaldehyde resin composition is preferably 0.5 to 40 parts by mass, more preferably 5 to 25 parts by mass, based on 100 parts by mass of the solid content of the resol-type phenol-formaldehyde resin. When the content of the amine compound is equal to or greater than the lower limit of the above range, the content of free formaldehyde in the resol-type phenol-formaldehyde resin tends to be reduced, and the amount of formaldehyde emitted from the aqueous binder tends to be sufficiently reduced. When the content of the amine compound is equal to or less than the upper limit of the above range, an aqueous binder that is excellent in water dilutability and has a reduced amount of ammonia emitted tends to be obtained. In this specification, the term "solid content" refers to non-volatile content excluding volatile substances (water, organic solvents, etc.). The solid content concentration of the resol-type phenol-formaldehyde resin can be measured in accordance with the provisions of JIS K6910, 5.6. In this specification, free formaldehyde refers to unreacted formaldehyde measured in accordance with the provisions of JIS K6910, 5.17.

[0021] The method for producing an aqueous binder according to the present embodiment may further include a resin synthesis step of synthesizing a phenol-formaldehyde resin when a phenol-formaldehyde resin composition obtained by adding an amine compound to a synthesized phenol-formaldehyde resin or a phenol-formaldehyde resin containing an amine compound obtained by synthesizing a phenol-formaldehyde resin using a catalyst containing an amine compound is used as the phenol-formaldehyde resin composition to be subjected to the acid addition step.

[0022] [Resin synthesis step] In the resin synthesis step, a phenol-based compound and an aldehyde-based compound are reacted in the presence of an alkaline catalyst to synthesize a resol-type phenol-formaldehyde resin.

[0023] [[Synthesis of resol-type phenol-formaldehyde resin]] The method of synthesizing a resol-type phenol-formaldehyde resin by reacting a phenol with an aldehyde in the presence of an alkali catalyst is not particularly limited, and a known method can be used. For example, a method of charging a phenol, an aldehyde, an alkali catalyst, water, etc. into a reaction vessel having a stirrer, a reflux condenser, and a temperature control mechanism, and maintaining the reaction at a desired reaction temperature for a desired reaction time can be mentioned. After the start of the reaction, an additional alkali catalyst and any additives, etc. may be added as necessary.

[0024] Phenols are compounds having an aromatic ring and a hydroxyl group bonded to the aromatic ring. Examples of phenols include phenol, alkylphenols (o, m, p cresols, o, m, p ethylphenols, xylenol isomers, etc.), polyaromatic ring phenols (α, β naphthols, etc.), polyhydric phenols (bisphenol A, bisphenol F, bisphenol S, pyrogallol, resorcin, catechol, hydroquinone, etc.). Among these, the practical substances are phenol, o, m, p cresols, xylenol isomers, resorcin, and catechol. The phenols may be used alone or in combination of two or more kinds.

[0025] The aldehyde is at least one compound selected from the group consisting of compounds having a formyl group and their polymers. Examples of the aldehyde include formaldehyde, paraformaldehyde, acetaldehyde, propylaldehyde, benzaldehyde, salicylaldehyde, glyoxal, etc. Among these, the practical substances are formaldehyde and paraformaldehyde. The aldehydes may be used alone or in combination of two or more kinds.

[0026] The molar ratio of aldehydes to phenols (aldehydes / phenols) is preferably 1.0 to 4.0, more preferably 1.5 to 2.5. When the molar ratio of aldehydes to phenols is equal to or greater than the lower limit of the above range, odor generation or a decrease in yield due to volatilization of unreacted phenols is easily suppressed. When the molar ratio of aldehydes to phenols is equal to or less than the upper limit of the above range, a large amount of unreacted aldehydes is suppressed from remaining, and the risk of formaldehyde volatilizing in the working environment during the manufacturing process and harming the health of workers can be reduced. In addition, the amount of aldehydes emitted from the obtained inorganic fiber heat insulating sound absorbing material tends to be smaller.

[0027] The alkaline catalyst is not particularly limited as long as it can promote the reaction between phenols and aldehydes, and various alkaline substances can be used. Specific examples include inorganic alkaline substances such as hydroxides of alkali metals such as sodium and potassium (sodium hydroxide, potassium hydroxide, etc.), hydroxides of alkaline earth metals such as calcium, magnesium, and barium (calcium hydroxide, magnesium hydroxide, barium hydroxide, etc.), sodium carbonate, and ammonia; and organic alkaline substances such as tertiary amines such as triethylamine, trimethylamine, and triethanolamine, and cyclic amines such as DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) and DBN (1,5-diazabicyclo[4.3.0]non-5-ene). In general, when an alkaline earth metal is used, the water dilutability and stability over time of the resin are lower than when an alkaline metal is used, but the water resistance is improved. This is because alkaline earth metals and their salts are less soluble in water than alkali metals. The alkali catalyst may be used alone or in combination of two or more kinds.

[0028] The amount of the alkali catalyst used is preferably 1 to 30 parts by mass per 100 parts by mass of the phenols. When the amount of the alkali catalyst used is equal to or more than the lower limit of the above range, the reaction tends to proceed sufficiently, and when it is equal to or less than the upper limit of the above range, the reaction tends to be easily controlled.

[0029] The reaction temperature of the reaction between the phenols and the aldehydes is preferably 50 to 90° C., and more preferably 60 to 80° C. When the reaction temperature is equal to or higher than the lower limit of the above range, a sufficient reaction rate tends to be obtained, and when the reaction temperature is equal to or lower than the upper limit of the above range, the reaction tends to be easily controlled. The reaction time can be set to, for example, 2 to 8 hours since this makes it easy to control the molecular weight.

[0030] The method for producing an aqueous binder according to the present embodiment may further include an amine compound addition step of adding an amine compound to a resol-type phenol-formaldehyde resin when a synthesized resol-type phenol-formaldehyde resin to which an amine compound has been added or a commercially available resol-type phenol-formaldehyde resin to which an amine compound has been added is used as the phenol-formaldehyde resin composition to be subjected to the acid addition step.

[0031] [Amine compound addition step] In the amine compound adding step, an amine compound is added to the resol-type phenol-formaldehyde resin. Examples of the amine compound include those described above in ((Amine compound)).

[0032] When an amine compound is added after synthesizing the resol-type phenol-formaldehyde resin in the above [Resin synthesis step], it is preferable to add the amine compound after lowering the temperature of the resol-type phenol-formaldehyde resin to less than 50° C. By adding the amine compound at less than 50° C., it is possible to suppress the reaction of the free phenols and free aldehydes contained in the resol-type phenol-formaldehyde resin with the amine compound to form a condensate, and it is possible to obtain an aqueous binder with excellent water dilutability. In this specification, free phenols and free aldehydes refer to unreacted phenols and aldehydes measured in accordance with the provisions of JIS K6910, 5.16 and 5.17, respectively.

[0033] The temperature of the resol-type phenol-formaldehyde resin when the amine compound is added is preferably less than 50° C., more preferably 10 to 40° C., and even more preferably 20 to 35° C. When the temperature of the resol-type phenol-formaldehyde resin when the amine compound is added is equal to or lower than the upper limit of the above range, an aqueous binder with excellent water dilutability tends to be obtained, and when it is equal to or higher than the lower limit of the above range, the amine compound tends to be easily dissolved in the resol-type phenol-formaldehyde resin, the heat of dissolution when the amine compound is added is mitigated, and temperature control tends to be easier.

[0034] The amount of the amine compound added is preferably 0.5 to 40 parts by mass, more preferably 5 to 25 parts by mass, based on 100 parts by mass of the solid content of the resol-type phenol-formaldehyde resin. When the amount of the amine compound added is equal to or greater than the lower limit of the above range, the content of free formaldehyde in the resol-type phenol-formaldehyde resin tends to be reduced, and the amount of formaldehyde emitted from the aqueous binder tends to be sufficiently reduced. When the content of the amine compound is equal to or less than the upper limit of the above range, an aqueous binder that is excellent in water dilutability and has a reduced amount of ammonia emitted tends to be obtained.

[0035] [Acid addition step] In the method for producing the aqueous binder of this embodiment, in the acid addition step, an acid is added to the phenol formaldehyde resin composition containing an amine compound, so that in the binder application step of producing the inorganic fiber heat insulating sound absorbing material, the amount of ammonia gas released by the decomposition of the amine compound in the aqueous binder due to contact with the high temperature inorganic fiber or exposure to heat from the immediately preceding fiberization step can be reduced. In addition, since an acid is used, discoloration (browning) of the inorganic fiber heat insulating sound absorbing material hardly occurs, compared to the case where a sugar compound is added to suppress the amount of ammonia gas released, and an inorganic fiber heat insulating sound absorbing material with a good hue can be obtained. Regarding the amount of acid added, if the amount is large, the water dilutability of the obtained aqueous binder decreases and precipitates are generated, which may induce clogging of the binder liquid delivery pipe or corrosion of the equipment due to the acid, so the acid is added in a range where the pH of the phenol-formaldehyde resin composition is 8.1 to 9.4 (the pH of the phenol-formaldehyde resin composition before the addition of the acid is about 9.7). The pH of the phenol-formaldehyde resin composition after the addition of the acid is preferably 8.3 to 9.2, more preferably 8.5 to 9.0, since the amount of ammonia gas emitted is more effectively reduced. In the method for producing the aqueous binder of this embodiment, the pH of the phenol formaldehyde resin composition immediately after the addition of the acid in the acid adding step is approximately the same as the pH of the finally obtained aqueous binder.

[0036] The timing of the acid addition step is preferably performed immediately before using the binder, since the stability of the resol-type phenol formaldehyde resin (binder) decreases when an acid is added, and the pot life is shortened. Specifically, it is preferably performed within 48 hours before using the binder, more preferably within 24 hours, and even more preferably within 12 hours. In addition, the acid is preferably added while stirring the phenol-formaldehyde resin composition in order to prevent a decrease in the water dilutability of the resin due to local over-neutralization. The temperature of the phenol formaldehyde resin composition when the acid is added is preferably less than 50°C, more preferably from 10 to 40°C, and even more preferably from 15 to 35°C.

[0037] (acid) The acid added in the acid addition step is not particularly limited as long as it does not impair the properties of the aqueous binder for use in an inorganic fiber heat insulating sound absorbing material, and examples thereof include inorganic acids such as sulfuric acid, boric acid, hydrochloric acid, nitric acid, phosphoric acid, and sulfamic acid, and organic acids such as formic acid, oxalic acid, acetic acid, citric acid, lactic acid, sulfanilic acid, benzoic acid, phenolsulfonic acid, paratoluenesulfonic acid, methanesulfonic acid, and lauric acid. From the viewpoints of cost and ease of use, sulfuric acid, phosphoric acid, citric acid, and lactic acid are preferred, and sulfuric acid is particularly preferred. The acids may be used alone or in combination of two or more.

[0038] [Water addition step] In the method for producing the aqueous binder of the present embodiment, in the water adding step, water is added to the phenol formaldehyde resin composition to adjust the solid content concentration. Examples of the water to be added in the water addition step include well water, tap water, distilled water, deionized water (ion-exchanged water), RO water, etc., and it is preferable that the water does not contain solids. From the viewpoints of cost and ease of use, well water, tap water, and distilled water are particularly preferable. The solid content concentration after adding water to the phenol formaldehyde resin composition, i.e., the solid content concentration of the aqueous binder, is preferably 1 to 50 mass%, more preferably 3 to 45 mass%, and even more preferably 5 to 40 mass%. When the solid content concentration of the aqueous binder is equal to or higher than the lower limit of the above range, the water content is appropriate, so that the curing step does not take too much time, and good productivity tends to be maintained. In addition, when the solid content concentration of the aqueous binder is equal to or lower than the upper limit of the above range, the fluidity of the aqueous binder tends to be prevented from decreasing. The solids concentration of the aqueous binder (phenol formaldehyde resin composition) can be measured in accordance with the provisions of JIS K6910, 5.6.

[0039] [Addition step of other ingredients] The method for producing an aqueous binder of this embodiment may further include an other component addition step of adding other components other than the resol-type phenol formaldehyde resin and the amine compound, within a range that does not impair the effects of the present invention. The order of the other component addition step in the method for producing an aqueous binder of this embodiment is preferably after the acid addition step, and may be, for example, after the acid addition step and before the water addition step, or may be after the water addition step. The other components are added within a range that does not significantly change the pH adjusted in the acid addition step. The temperature of the phenol formaldehyde resin composition when other components are added is preferably less than 50°C, more preferably from 10 to 40°C, and even more preferably from 15 to 35°C.

[0040] The other components may be known components that are generally known to be blended into aqueous binders for inorganic fiber heat insulating sound absorbing materials, such as curing accelerators, silane coupling agents, urea, known formaldehyde scavengers, water repellents (silicone-based water repellents, fluorine-based water repellents, etc.), dust inhibitors (heavy oil water dispersions, etc.), rust inhibitors, colorants, and neutralizing agents for neutralizing alkaline components eluted from inorganic fibers such as glass. The other components may be used alone or in combination of two or more.

[0041] Examples of the hardening accelerator include ammonium salts such as ammonium sulfate, ammonium chloride, and ammonium phosphate. The amount of the curing accelerator added is preferably 0 to 10 parts by mass, and more preferably 3 to 6 parts by mass, based on 100 parts by mass of the solid content of the resol type phenol formaldehyde resin.

[0042] The silane coupling agent is not particularly limited, and examples thereof include aminosilane coupling agents such as γ-aminopropyltriethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, and γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, and epoxy silane coupling agents such as γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropylmethyldimethoxysilane. The amount of the silane coupling agent added is preferably 0 to 2 parts by mass, and more preferably 0.1 to 1 part by mass, based on 100 parts by mass of the solid content of the resol type phenol formaldehyde resin.

[0043] In the production of inorganic fiber heat insulating sound absorbing materials, there is a problem of formaldehyde volatilizing from the aqueous binder during the process of applying the aqueous binder to the inorganic fibers, but by adding urea or a known formaldehyde scavenger, the free formaldehyde in the phenolic resin is captured by the urea, reducing the amount of free formaldehyde, and the amount of formaldehyde volatilized during the production process can be reduced, improving the working environment. Known formaldehyde scavengers include, for example, the formaldehyde scavengers described in JP-A-2001-178805. In the following, the urea addition step of adding urea will be particularly described. A known formaldehyde scavenger can also be added in the same manner as in the urea addition step, and the preferred range of the amount of the formaldehyde scavenger to be added may be the same as the preferred range of the amount of urea to be added.

[0044] [[Urea addition step]] The urea addition step of adding urea to the phenol-formaldehyde resin composition is preferably performed after the acid addition step and before the water addition step, from the viewpoints of efficiently neutralizing the acid of the amine compound in the phenol-formaldehyde resin composition and efficiently reacting the urea with free formaldehyde.

[0045] The amount of urea added is preferably 5 to 100 parts by mass, more preferably 10 to 80 parts by mass, and even more preferably 20 to 70 parts by mass, relative to 100 parts by mass of the solid content of the resol-type phenol-formaldehyde resin. When the amount of urea added is equal to or greater than the lower limit of the above range, the content of free formaldehyde in the resol-type phenol-formaldehyde resin is reduced well, and the amount of formaldehyde emitted from the aqueous binder tends to be reduced well. When the amount of urea added is equal to or less than the upper limit of the above range, the aqueous binder tends to have excellent water dilution properties, and the pH of the phenol-formaldehyde resin composition does not change significantly (out of the range of pH 8.1 to 9.4) (pH of urea is about 9.0), and the pH of the phenol-formaldehyde resin composition immediately after adjusting the pH in the acid addition step and the pH of the finally obtained aqueous binder are almost the same, and the amount of ammonia gas emitted from the aqueous binder is reduced well.

[0046] [Water-based binder for inorganic fiber heat insulation and sound absorbing materials] The aqueous binder for an inorganic fiber heat insulating sound absorbing material of this embodiment is an aqueous binder produced by the above-mentioned method for producing an aqueous binder for an inorganic fiber heat insulating sound absorbing material of this embodiment. The aqueous binder of the present embodiment is used to bind inorganic fibers such as glass wool, rock wool, and ceramic fibers in inorganic fiber products. The aqueous binder of the present embodiment contains a phenol-formaldehyde resin composition containing the above-mentioned amine compound, an acid, and water for adjusting the concentration, and may further contain other components such as urea, a curing accelerator, a silane coupling agent, a dust inhibitor, a rust inhibitor, a water repellent, and a colorant, as necessary, within a range that does not impair the effects of the present invention.

[0047] The pH of the aqueous binder is 8.1 to 9.4, preferably 8.3 to 9.2, and more preferably 8.5 to 9.0. When the pH of the aqueous binder is in the above range, the amount of ammonia gas emitted is effectively reduced, and the risk of clogging of the binder liquid delivery pipe due to the formation of precipitates caused by a decrease in water dilution and acid corrosion of the equipment is reduced. The pH of the aqueous binder is approximately the same as the pH of the phenol formaldehyde resin composition immediately after the acid is added in the acid adding step.

[0048] As described in the above [Water Addition Step], the solid content concentration of the aqueous binder is preferably 1 to 50 mass%, more preferably 5 to 45 mass%, and even more preferably 10 to 40 mass%. When the solid content concentration of the aqueous binder is equal to or higher than the lower limit of the above range, the water content is appropriate, so that the curing step does not take too much time, and good productivity tends to be maintained. In addition, when the solid content concentration of the aqueous binder is equal to or lower than the upper limit of the above range, the fluidity of the aqueous binder tends to be prevented from decreasing.

[0049] The temperature of the aqueous binder before use is preferably less than 50°C, more preferably from 10 to 40°C, and even more preferably from 20 to 35°C.

[0050] [Manufacturing method of inorganic fiber heat insulation and sound absorbing material] The thermal insulating sound absorbing inorganic fiber material of the present embodiment can be obtained by applying the aqueous binder of the present embodiment described above to inorganic fibers, and then heating and curing the aqueous binder to form the material. More specifically, for example, molten inorganic raw materials are fiberized in a fiberizing device, and immediately thereafter, an aqueous binder is applied to the inorganic fibers. Next, the inorganic fibers to which the aqueous binder has been applied are piled up (collected) on a perforated conveyor to form a bulky intermediate for an inorganic fiber heat insulating sound absorbing material, which is then fed to a pair of upper and lower perforated conveyors spaced apart from each other to obtain a desired thickness, and heated while being compressed in a narrow space to harden the aqueous binder to form an inorganic fiber heat insulating sound absorbing material. If necessary, a skin material or the like is applied, and the inorganic fiber heat insulating sound absorbing material can be obtained by cutting the inorganic fiber heat insulating sound absorbing material to the desired width and length.

[0051] The method of applying the aqueous binder to the inorganic fiber includes a method of applying or spraying using a spray device or the like. The timing of applying the aqueous binder to the inorganic fiber may be after fiberization, and from the viewpoint of efficiently applying the aqueous binder, it is preferable to apply it immediately after fiberization. The amount of the aqueous binder applied varies depending on the density and use of the inorganic fiber heat insulating sound absorbing material, but is preferably 0.5 to 30 mass% in terms of solid content, and more preferably 0.5 to 20 mass%, based on the mass of the inorganic fiber heat insulating sound absorbing material to which the aqueous binder has been applied.

[0052] The method of heating the inorganic fiber to which the aqueous binder is applied includes, for example, heating with a hot air oven. The heating temperature in the hot air oven can be, for example, 200 to 350°C. When the heating temperature is equal to or higher than the lower limit of the above range, the curing of the aqueous binder tends to proceed sufficiently, and the amount of formaldehyde emitted tends to be sufficiently reduced. When the heating temperature is equal to or lower than the upper limit of the above range, the aqueous binder is less likely to decompose, and the decrease in yield and the decrease in mechanical strength tend to be suppressed. The heat curing time can be appropriately adjusted between 30 seconds and 10 minutes depending on the density and thickness of the inorganic fiber heat insulating sound absorbing material.

[0053] [Inorganic fiber heat insulation and sound absorbing material] The thermal insulation sound-absorbing inorganic fiber material of the present embodiment includes inorganic fibers and the cured product of the aqueous binder for the thermal insulation sound-absorbing inorganic fiber material of the present embodiment, which fixes (holds) the inorganic fibers. That is, the thermal insulation sound-absorbing inorganic fiber material can be obtained by applying the aqueous binder to inorganic fibers and molding the aqueous binder by heating and curing it. The inorganic fiber is not particularly limited, and glass wool, rock wool, etc., which are used in ordinary heat insulating sound absorbing materials, can be used. As a method for fiberizing the inorganic fiber, various methods such as a flame method, a blowing method, and a centrifugal method (rotary method) can be used. When the inorganic fiber is glass wool, it is preferable to use the centrifugal method. The inorganic fiber heat insulating sound absorbing material may be used as it is, or may be covered with a skin material such as paper, synthetic resin film, metal foil film, nonwoven fabric, woven fabric, or a combination of these. The density of the inorganic fiber heat insulating and sound absorbing material may be the density used for ordinary heat insulating and sound absorbing materials, and is preferably 5 to 300 kg / m 3 It is. EXAMPLES

[0054] The present invention will be described in more detail below with reference to examples. The present invention is not limited to the following examples as long as it does not depart from the gist of the present invention.

[0055] The measurement and evaluation methods used are as follows:

[0056] [Ammonia emission rate] (1) Laboratory evaluation 10 g of the aqueous binder (solid content concentration 40% by mass) was placed in a 20 mL glass bottle, and the bottle was left in a 250 mL plastic container without a lid. Next, 10 mL of 20 mmol / L methanesulfonic acid solution was placed in another 20 mL glass bottle, and the bottle was left in the plastic container without a lid. The plastic container was closed with a lid and heated at 80°C for 10 minutes, and the ammonia generated from the aqueous binder was dissolved in the methanesulfonic acid solution. After the heating was completed, the glass bottle containing the aqueous methanesulfonic acid solution was removed from the plastic container and the lid was immediately closed. The amount of ammonia dissolved in the methanesulfonic acid aqueous solution was quantified by ion chromatography under the following measurement conditions. The measurement was performed twice, and the average value was used as the measured value. In Table 1, the measurement results are shown as relative values, with the measured value of Comparative Example 1 taken as 100. -Measurement conditions- Apparatus: Dionex Aquion (Thermo Fisher Scientific) Column: Dionex IonPac CS12A (Thermo Fisher Scientific) Eluent: 20mmol / L methanesulfonic acid aqueous solution Detector: Electrical conductivity detector Flow rate: 1.0mL / min Injection volume: 25μL Calibration curve standard solution: 1000 mg / L ammonium ion standard solution (Kanto Chemical Co., Ltd.) (2) Actual machine evaluation Density 64kg / m 3 A glass wool heat insulating sound absorbing material with an aqueous binder adhesion rate of 6.0 mass% was manufactured, and the concentration (ppm by volume) of ammonia gas emitted from the aqueous binder in the aqueous binder application process was measured under the following measurement conditions using an ammonia detector tube. The measurement was performed by sucking the exhaust gas generated in the aqueous binder application process with the detector tube from inside a duct that sends the gas from the binder application process to the exhaust gas treatment equipment. The measurement was performed three times, and the average value was taken as the measured value. In Table 2, the measurement results are shown as relative values ​​with the measured value of Comparative Example 1 set at 100. -Measurement conditions- Detector tube: Ammonia No. 3La (manufactured by Gastec Corporation) Suction volume: 100mL

[0057] [pH] The pH of the phenol formaldehyde resin composition and the aqueous binder was measured using a pH meter "F-74" (manufactured by Horiba, Ltd.) in accordance with the provision of 5.4 of JIS K6910:2007.

[0058] [Example 1] As a phenol-formaldehyde resin composition containing an amine compound, "PL-7740" (manufactured by Gun-ei Chemical Industry Co., Ltd.) was used, in which triethylamine was used as the amine catalyst during resin synthesis and monoethanolamine was added as an amine compound other than the catalyst. Sulfuric acid was added to a phenol formaldehyde resin composition (23° C.) and stirred to adjust the pH to 9.3. Next, urea, ammonium sulfate, and aminosilane were added and mixed in this order so that the ratios relative to 60 parts by mass of the solid content of the phenol-formaldehyde resin composition (23°C) were 40 parts by mass of urea, 3.5 parts by mass of ammonium sulfate, and 0.2 parts by mass of aminosilane, and then distilled water was added to adjust the concentration to 40% by mass of the solid content, thereby obtaining an aqueous binder. The ammonia emission amount (laboratory evaluation) and pH measurement results of the obtained aqueous binder are shown in Table 1.

[0059] [Examples 2 to 10] Aqueous binders were obtained in the same manner as in Example 1, except that the type and amount of acid and the amount of each component were changed as shown in Table 1. The pH and ammonia emission amount (laboratory evaluation) of the obtained aqueous binder are shown in Table 1.

[0060] [Comparative Example 1] An aqueous binder was obtained in the same manner as in Example 1, except that sulfuric acid was not added. The pH and ammonia emission amount (laboratory evaluation) of the obtained aqueous binder are shown in Table 1.

[0061] [Examples 11 and 12] Aqueous binders were obtained in the same manner as in Example 1, except that the amount of acid added was changed as shown in Table 2 and well water was used instead of distilled water. Table 2 shows the measurement results of the pH and ammonia emission amount (evaluated using an actual machine) of the obtained aqueous binder.

[0062] [Comparative Example 2] An aqueous binder was obtained in the same manner as in Comparative Example 1, except that well water was used instead of distilled water. Table 2 shows the measurement results of the pH and ammonia emission amount (evaluated using an actual machine) of the obtained aqueous binder.

[0063] [Table 1]

[0064] [Table 2] [Industrial Applicability]

[0065] According to the method for producing an aqueous binder for an inorganic fiber thermal insulation sound-absorbing material of the present invention, it is possible to obtain an aqueous binder that effectively reduces the amount of ammonia gas emitted during the production of an inorganic fiber thermal insulation sound-absorbing material, and the aqueous binder can be suitably used for the production of an inorganic fiber thermal insulation sound-absorbing material.

Claims

1. A method for producing an aqueous binder for inorganic fiber heat insulating and sound absorbing materials, an acid addition step of adding an acid to a phenol-formaldehyde resin composition containing a resol-type phenol-formaldehyde resin and an amine compound, the acid being added while stirring the phenol-formaldehyde resin composition, and the temperature of the phenol-formaldehyde resin composition at the time of adding the acid being less than 50° C.; a step of adding other components after the acid addition step, in which other components other than the resol-type phenol-formaldehyde resin and the amine compound are added; After the step of adding other components, a water addition step of adding water to adjust the solid content concentration; Including, the resol-type phenol-formaldehyde resin is a resol-type phenol-formaldehyde resin synthesized by reacting a phenol with a formaldehyde using a catalyst containing a tertiary amine and / or a cyclic amine, the amine compound contains an amine compound other than an amine compound contained in a catalyst used in the synthesis of the resol-type phenol-formaldehyde resin, The other components include a curing accelerator and a silane coupling agent, The pH of the aqueous binder for inorganic fiber heat insulating and sound absorbing material is 8.1 to 9.

4. A method for producing an aqueous binder for an inorganic fiber heat insulating and sound absorbing material, comprising:

2. 2. The method for producing an aqueous binder for an inorganic fiber heat insulating sound absorbing material according to claim 1, wherein the resol type phenol formaldehyde resin is a resol type phenol formaldehyde resin synthesized by reacting a phenol with a formaldehyde using a catalyst containing triethylamine.

3. The method for producing an aqueous binder for a thermal insulating and acoustic inorganic fiber material according to claim 1, wherein the amine compound other than the amine compound contained in the catalyst is monoethanolamine.

4. The method for producing an aqueous binder for an inorganic fiber heat insulating and sound absorbing material according to claim 1, wherein the acid is sulfuric acid.

5. A method for producing an aqueous binder for inorganic fiber thermal insulation and sound-absorbing material as described in claim 1, wherein the other component addition step includes a urea addition step of adding urea.

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