Aqueous binder for inorganic fiber heat insulation sound absorption material, and inorganic fiber heat insulation sound absorption material

Abstract

To provide an aqueous binder for an inorganic fiber heat insulation sound absorption material reduced in stickiness more than a prior polycarboxylic acid-based binder, and an inorganic fiber heat insulation sound absorption material using the same.SOLUTION: An aqueous binder for an inorganic heat insulation sound absorption material contains a polycarboxylic acid and a crosslinking agent thereof, wherein the crosslinking agent includes (crosslinking agent 1) an alkanolamine, and (crosslinking agent 2) a hydroxycarboxylic acid having a carbon number of a part except for a carboxyl group of 5 or less and / or a lactone obtained by subjecting the hydroxycarboxylic acid to dehydration condensation, the polycarboxylic acid includes a polycarboxylic acid having a weight average molecular weight and an acid value of specific ranges, a ratio of a total mole number of hydroxyl groups, amino groups and imino groups of the polycarboxylic acid, and the crosslinking agents 1 and 2 to a total mole number of carboxyl groups of the polycarboxylic acid, and the crosslinking agents 1 and 2 is 0.2 or more, and the ratio of the crosslinking agents 1 and 2 to a total mole number of carboxyl groups is 6.0 or less (the lactone has a value of the hydroxycarboxylic acid before dehydration condensation).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an aqueous binder for inorganic fiber heat insulating and sound absorbing materials and an inorganic fiber heat insulating and sound absorbing material.

Background Art

[0002] Inorganic fiber heat insulating and 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 phenol-urea-formaldehyde-based binder (hereinafter also referred to as "phenol-based binder") and an aqueous binder are known. However, since formaldehyde may be generated during or after curing of the phenol-based binder, an aqueous binder free of formaldehyde has been preferably used in response to the demand for reducing environmental load. As such an aqueous binder, for example, a polycarboxylic acid-based binder as described in Patent Documents 1 to 9 is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

Patent Document 9

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, although the above polycarboxylic acid-based binder does not emit formaldehyde, since its main component is a polymer, it has a higher viscosity and is stickier compared to a phenolic binder with a low molecular weight main component. Therefore, when manufacturing an inorganic fiber heat insulating and sound absorbing material, the mixture of fibers and the uncured binder easily adheres to the production equipment, resulting in a decrease in yield due to adhesion loss, a decrease in productivity due to the cleaning time required to remove the adhered matter caused by stickiness, a large amount of cleaning water used to clean a large amount of adhered matter, and high costs due to these, which have been problems.

[0005] Therefore, an object of the present invention is to provide an aqueous binder for an inorganic fiber heat insulating and sound absorbing material with reduced stickiness compared to conventional polycarboxylic acid-based binders, and an inorganic fiber heat insulating and sound absorbing material using the same.

Means for Solving the Problems

[0006] As a result of intensive studies, the present inventors have found that by containing a polycarboxylic acid and a crosslinking agent containing a specific hydroxycarboxylic acid and / or a lactone which is its dehydration condensate, and setting the ratio of the total number of moles of hydroxyl groups, amino groups, and imino groups of the specific crosslinking agent to the total number of moles of carboxyl groups of the polycarboxylic acid and the specific crosslinking agent, and the ratio of the total number of moles of hydroxyl groups, amino groups, and imino groups of the specific crosslinking agent to the total number of moles of carboxyl groups of the specific crosslinking agent within specific ranges, the above problems can be solved, and the present invention has been completed.

[0007] That is, the present invention is as follows. [1] An aqueous binder for an inorganic fiber heat insulating and sound absorbing material containing a polycarboxylic acid and a crosslinking agent for the polycarboxylic acid, wherein the crosslinking agent is (Crosslinking Agent 1) an alkanolamine, and It contains a hydroxycarboxylic acid in which the carbon number of the portion other than the carboxyl group is 5 or less and / or a lactone formed by dehydration condensation of the hydroxycarboxylic acid, The polycarboxylic acid contains a polycarboxylic acid having a weight average molecular weight of 1,000 to 20,000 and an acid value of 500 to 900 mgKOH / g, The ratio of the total number of moles of hydroxyl groups, amino groups and imino groups of the polycarboxylic acid, the crosslinking agent 1 and the crosslinking agent 2 to the total number of moles of carboxyl groups of the polycarboxylic acid, the crosslinking agent 1 and the crosslinking agent 2 is 0.2 or more, The ratio of the total number of moles of hydroxyl groups, amino groups and imino groups of the crosslinking agent 1 and the crosslinking agent 2 to the total number of moles of carboxyl groups of the crosslinking agent 1 and the crosslinking agent 2 is 6.0 or less An aqueous binder for an inorganic fiber heat insulating and sound absorbing material, characterized in that. When the crosslinking agent 2 contains a lactone, the number of moles of each functional group in the hydroxycarboxylic acid before dehydration condensation is taken as the number of moles of each functional group in the lactone. [2] Comprising inorganic fibers and a cured product of the aqueous binder for an inorganic fiber heat insulating and sound absorbing material according to [1] for fixing the inorganic fibers An inorganic fiber heat insulating and sound absorbing material, characterized in that. [3] A method for reducing the stickiness of an aqueous binder for an inorganic fiber heat insulating and sound absorbing material containing a polycarboxylic acid and a crosslinking agent for the polycarboxylic acid, As the crosslinking agent (Crosslinking agent 1) An alkanolamine, (Crosslinking agent 2) Containing a crosslinking agent containing a hydroxycarboxylic acid in which the carbon number of the portion other than the carboxyl group is 5 or less and / or a lactone formed by dehydration condensation of the hydroxycarboxylic acid, The ratio of the total number of moles of hydroxyl groups, amino groups and imino groups of the polycarboxylic acid, the crosslinking agent 1 and the crosslinking agent 2 to the total number of moles of carboxyl groups of the polycarboxylic acid, the crosslinking agent 1 and the crosslinking agent 2 is 0.2 or more, The ratio of the total number of moles of hydroxyl groups, amino groups, and imino groups of the crosslinking agent 1 and the crosslinking agent 2 to the total number of moles of carboxyl groups of the crosslinking agent 1 and the crosslinking agent 2 is 6.0 or less. A method characterized by this. When the crosslinking agent 2 contains a lactone, the number of moles of each functional group in the hydroxycarboxylic acid before dehydration condensation is taken as the number of moles of each functional group in the lactone. [4] A method for producing an aqueous binder for an inorganic fiber heat insulating and sound absorbing material containing a polycarboxylic acid and a crosslinking agent for the polycarboxylic acid, with reduced stickiness, As the crosslinking agent (Crosslinking agent 1) An alkanolamine, (Crosslinking agent 2) A crosslinking agent containing a hydroxycarboxylic acid in which the carbon number of the portion other than the carboxyl group is 5 or less and / or a lactone obtained by dehydration condensation of the hydroxycarboxylic acid is included, The ratio of the total number of moles of hydroxyl groups, amino groups, and imino groups of the polycarboxylic acid, the crosslinking agent 1, and the crosslinking agent 2 to the total number of moles of carboxyl groups of the polycarboxylic acid, the crosslinking agent 1, and the crosslinking agent 2 is 0.2 or more, The ratio of the total number of moles of hydroxyl groups, amino groups, and imino groups of the crosslinking agent 1 and the crosslinking agent 2 to the total number of moles of carboxyl groups of the crosslinking agent 1 and the crosslinking agent 2 is 6.0 or less A production method characterized by this. When the crosslinking agent 2 contains a lactone, the number of moles of each functional group in the hydroxycarboxylic acid before dehydration condensation is taken as the number of moles of each functional group in the lactone.

Advantages of the Invention

[0008] According to the present invention, it is possible to provide an aqueous binder for an inorganic fiber heat insulating and sound absorbing material with reduced stickiness compared to conventional polycarboxylic acid-based binders, and an inorganic fiber heat insulating and sound absorbing material using the same.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, the embodiments for carrying out 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 embodiments and can be variously modified and implemented within the scope of the gist thereof.

[0010] 〈Aqueous Binder for Inorganic Fiber Heat Insulating and Sound Absorbing Material〉 The aqueous binder for inorganic fiber heat insulating and sound absorbing material of the present embodiment (hereinafter also simply referred to as "aqueous binder") contains a polycarboxylic acid and a crosslinking agent for the polycarboxylic acid. The crosslinking agent includes (crosslinking agent 1) an alkanolamine and (crosslinking agent 2) a hydroxycarboxylic acid in which the carbon number of the portion other than the carboxyl group is 5 or less and / or a lactone obtained by dehydration condensation of the hydroxycarboxylic acid. The ratio of the total number of moles of the hydroxyl group, amino group, and imino group of the polycarboxylic acid, crosslinking agent 1, and crosslinking agent 2 to the total number of moles of the carboxyl group of the polycarboxylic acid, crosslinking agent 1, and crosslinking agent 2 is 0.2 or more, and the ratio of the total number of moles of the hydroxyl group, amino group, and imino group of crosslinking agent 1 and crosslinking agent 2 to the total number of moles of the carboxyl group of crosslinking agent 1 and crosslinking agent 2 is 6.0 or less. However, when crosslinking agent 2 contains a lactone, the number of moles of each functional group in the hydroxycarboxylic acid before dehydration condensation is taken as the number of moles of each functional group in the lactone. The aqueous binder for inorganic fiber heat insulating and sound absorbing material of the present embodiment has a lower viscosity and less stickiness than conventional polycarboxylic acid-based binders. Therefore, it is possible to suppress the adhesion of the mixture of fibers and uncured binder to the production equipment during the production of inorganic fiber heat insulating and sound absorbing materials. As a result, it is possible to improve the yield reduction due to adhesion loss, improve productivity by shortening the cleaning time for removing the adhered matter from the production equipment, reduce the amount of cleaning water for cleaning the adhered matter, and lead to cost reduction.

[0011] [Polycarboxylic Acid] The polycarboxylic acid contained in the aqueous binder of the present embodiment includes a polycarboxylic acid (hereinafter also referred to as "high molecular weight polycarboxylic acid") having a weight average molecular weight of 1000 to 20000 and an acid value of 500 to 900 mgKOH / g.

[0012] [[High Molecular Weight Polycarboxylic Acid]] The high molecular weight polycarboxylic acid preferably has an ethylenically unsaturated monomer having a carboxyl group as a monomer unit, that is, it is preferably obtained by polymerizing an ethylenically unsaturated monomer having a carboxyl group. The high molecular weight polycarboxylic acid having an ethylenically unsaturated monomer having a carboxyl group as a monomer unit may consist only of monomer units derived from an ethylenically unsaturated monomer having a carboxyl group, or may consist of monomer units derived from an ethylenically unsaturated monomer having a carboxyl group and monomer units derived from a copolymer monomer having no carboxyl group. The content of the monomer unit derived from the ethylenically unsaturated monomer having a carboxyl group is preferably 90% by mass or more, more preferably 95% by mass or more, and may be 100% by mass, based on 100% by mass of the total amount of the monomer units of the high molecular weight polycarboxylic acid.

[0013] Examples of the ethylenically unsaturated monomer having a carboxyl group include (meth)acrylic acid, crotonic acid, fumaric acid, maleic acid, 2-methylmaleic acid, itaconic acid, 2-methylitaconic acid, α-β-methyleneglutaric acid, maleic acid monoalkyl, fumaric acid monoalkyl, maleic anhydride, acrylic anhydride, β-(meth)acryloyloxyethyl hydrogen phthalate, β-(meth)acryloyloxyethyl hydrogen maleate, and β-(meth)acryloyloxyethyl hydrogen succinate. Among these, (meth)acrylic acid is preferred from the viewpoint of easy control of the molecular weight of the polycarboxylic acid. Also, when adjusting the acid value of the polycarboxylic acid to a high value (for example, around 900 mgKOH / g), it is preferable to use maleic acid or fumaric acid. Note that "(meth)acryl" means acrylic or methacryl, and the same applies to similar compounds. The ethylenically unsaturated monomer having a carboxyl group may be used alone or in combination of two or more.

[0014] Examples of the copolymerization monomer having no carboxyl group include acrylic monomers such as methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cetyl (meth) acrylate, n-stearyl (meth) acrylate, diethylene glycol ethoxy (meth) acrylate, methyl-3-methoxy (meth) acrylate, ethyl-3-methoxy (meth) acrylate, butyl-3-methoxy (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, tetrahydrofurfuryl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, mono (meth) acrylate of polyol with trivalent or higher valency, aminoalkyl (meth) acrylate, N-alkylaminoalkyl (meth) acrylate, N,N-dialkylaminoalkyl (meth) acrylate; vinyl monomers such as vinyl alkyl ether, N-alkylvinylamine, N,N-dialkylvinylamine, N-vinylpyridine, N-vinylimidazole, N-(alkyl)aminoalkylvinylamine; amide monomers such as (meth)acrylamide, N-alkyl (meth)acrylamide, N,N-dialkyl (meth)acrylamide, N,N-dialkylaminoalkyl (meth)acrylamide, diacetone (meth)acrylamide, N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone; aliphatic unsaturated hydrocarbons such as ethylene, propylene, isobutylene, isoprene, butadiene; styrene monomers such as styrene, α-methylstyrene, p-methoxystyrene, vinyltoluene, p-hydroxystyrene, p-acetoxystyrene; vinyl ester monomers such as vinyl acetate, vinyl propionate; acrylonitrile, glycidyl (meth) acrylate, etc. The copolymerization monomer having no carboxyl group may be used alone or in combination of two or more.

[0015] The weight-average molecular weight of the high-molecular-weight polycarboxylic acid is from 1,000 to 20,000, preferably from 1,500 to 15,000, more preferably from 2,000 to 10,000. When the weight-average molecular weight of the polycarboxylic acid is 1,000 or more, it is easy to obtain an aqueous binder with high strength. When it is 20,000 or less, the fluidity (viscosity) of the aqueous binder tends to be good. The weight-average molecular weight is a value based on standard polyacrylic acid measured by gel permeation chromatography (GPC), and specifically, it can be measured by the method described in the examples below.

[0016] The acid value of the high-molecular-weight polycarboxylic acid is from 500 to 900 mgKOH / g, preferably from 500 to 850 mgKOH / g, more preferably from 550 to 800 mgKOH / g. When the acid value of the polycarboxylic acid is within the above range, the strength of the cured product obtained by heating the aqueous binder tends to be improved. The acid value means the mass (mgKOH) of potassium hydroxide required to neutralize 1 g of the polycarboxylic acid.

[0017] The content of the high-molecular-weight polycarboxylic acid in the total amount of the polycarboxylic acid is preferably 90% by mass or more, more preferably 95% by mass or more, and may be 100% by mass.

[0018] The content (in terms of solid content) of the polycarboxylic acid in the aqueous binder of this embodiment is preferably 25 to 80% by mass, more preferably 35 to 75% by mass, still more preferably 40 to 70% by mass, based on the total mass (in terms of solid content) of the polycarboxylic acid and the crosslinking agent. When the content of the polycarboxylic acid is within the above range, the viscosity is more reduced and the aqueous binder tends to be less sticky.

[0019] [Crosslinking agent] The crosslinking agent contained in the aqueous binder of this embodiment is not particularly limited as long as it contains (crosslinking agent 1) alkanolamine and (crosslinking agent 2) hydroxycarboxylic acid in which the carbon number of the portion other than the carboxyl group is 5 or less and / or a lactone formed by dehydration condensation of the hydroxycarboxylic acid, and may contain a crosslinking agent of polycarboxylic acid other than crosslinking agent 1 and crosslinking agent 2. By containing, as a crosslinking agent, crosslinking agent 2 which has a low molecular weight, low viscosity, and good water solubility in the aqueous binder of this embodiment, the ratio of the polymer component (polycarboxylic acid) in the aqueous binder decreases, so that the viscosity is reduced and the aqueous binder has less stickiness. The content (in terms of solid content) of the crosslinking agent in the aqueous binder of this embodiment is preferably 20 to 75% by mass, more preferably 25 to 65% by mass, and still more preferably 30 to 60% by mass with respect to the total mass (in terms of solid content) of the polycarboxylic acid and the crosslinking agent. When the content of the crosslinking agent is within the above range, the viscosity tends to be further reduced and the aqueous binder has less stickiness.

[0020] [[Crosslinking agent 1]] The alkanolamine of crosslinking agent 1 is not particularly limited, but those having 1 to 6 carbon atoms in the alkanol group are preferable, and those having 1 to 3 carbon atoms are more preferable. Specific examples of the alkanolamine include monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, N-methylethanolamine, N-methyldiethanolamine, etc. Among them, diethanolamine and triethanolamine are preferable, and diethanolamine is more preferable.

[0021] The content (in terms of solid content) of crosslinking agent 1 in the total amount of the crosslinking agent is preferably 10 to 70% by mass, more preferably 20 to 65% by mass, and still more preferably 25 to 60% by mass based on the total mass of the crosslinking agent in terms of solid content. When the content of crosslinking agent 1 is within the above range, the viscosity tends to be further reduced and the aqueous binder has less stickiness.

[0022] [Crosslinking agent 2] (Hydroxycarboxylic acid) A hydroxycarboxylic acid is a compound having at least one carboxyl group and at least one hydroxyl group other than the hydroxyl group in the carboxyl group respectively. The hydroxycarboxylic acid of the crosslinking agent 2 is not particularly limited as long as the number of carbon atoms in the portion other than the carboxyl group is 5 or less. The number of carbon atoms in the portion other than the carboxyl group of the hydroxycarboxylic acid is preferably 1 to 5, more preferably 1 to 4, and still more preferably 2 to 4. Also, the molecular weight of the hydroxycarboxylic acid is preferably 75 to 300, more preferably 75 to 250, and still more preferably 85 to 200.

[0023] Examples of the hydroxycarboxylic acid include aliphatic hydroxycarboxylic acids or alicyclic hydroxycarboxylic acids. Among them, aliphatic hydroxycarboxylic acids are preferred from the viewpoint of water solubility. Specific examples of the aliphatic hydroxycarboxylic acid include lactic acid, citric acid, hydroxybutyric acid, glycolic acid, tartaric acid, malic acid, glyceric acid, lactyl lactic acid, isocitric acid, 3-hydroxypropionic acid, tartronic acid, etc. Among them, lactic acid (the mixing ratio of L-form and D-form is not particularly limited), citric acid, etc., which are hydroxycarboxylic acids obtained from plants (such as corn and sugarcane) as raw materials, are particularly preferred because the substantial carbon dioxide emission amount becomes zero during incineration and the environmental load can be reduced.

[0024] (Lactone) The lactone of the crosslinking agent 2 is not particularly limited as long as it is a lactone obtained by dehydration condensation of the above-mentioned hydroxycarboxylic acid. For example, γ-butyrolactone, β-propiolactone, δ-valerolactone, γ-valerolactone, ε-caprolactone, etc. can be mentioned.

[0025] The crosslinking agent 2 preferably consists only of hydroxycarboxylic acid, but may also consist of both hydroxycarboxylic acid and lactone, or may consist only of lactone. When the crosslinking agent 2 contains both a hydroxycarboxylic acid and a lactone, when the hydroxycarboxylic acid is the main component, the content (in terms of solid content) of the hydroxycarboxylic acid in the total amount of the crosslinking agent 2 (in terms of solid content) is preferably 85% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass or more. Also, when the crosslinking agent 2 contains both a hydroxycarboxylic acid and a lactone, when the lactone is the main component, the content (in terms of solid content) of the lactone in the total amount of the crosslinking agent 2 (in terms of solid content) is preferably 85% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass or more.

[0026] The content (in terms of solid content) of the crosslinking agent 2 in the total amount of the crosslinking agent is preferably 30 to 90% by mass, more preferably 35 to 80% by mass, and still more preferably 40 to 75% by mass based on the total mass of the crosslinking agent in terms of solid content. When the content of the crosslinking agent 2 is within the above range, the ratio of the polymer component (polycarboxylic acid) in the aqueous binder is favorably reduced, and the viscosity is further reduced, resulting in an aqueous binder with less stickiness.

[0027] [Other Additives] The aqueous binder of this embodiment preferably contains a silane coupling agent in addition to the polycarboxylic acid and the crosslinking agent, and may contain other additives such as a curing accelerator, a rust inhibitor, a neutralizing agent, a dustproof agent (such as a heavy oil aqueous dispersion), a coloring agent, and a pH adjuster as needed.

[0028] The silane coupling agent acts at the interface between the inorganic fiber and the cured product of the aqueous binder, and can improve the adhesion of the cured product of the aqueous binder to the inorganic fiber. Examples of the silane coupling agent include aminosilane coupling agents such as γ-aminopropyltriethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, and epoxy silane coupling agents such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane. These can be used alone or in combination of two or more.

[0029] Examples of the curing accelerator include Bronsted acids, Lewis acids or their salts, and these can be used alone or in combination of two or more. Preferred examples are hypophosphites or sulfites. Examples of the hypophosphite include sodium hypophosphite, lithium hypophosphite, potassium hypophosphite, ammonium hypophosphite, calcium hypophosphite, magnesium hypophosphite, and strontium hypophosphite. Examples of the sulfite include lithium hydrogen sulfite, sodium hydrogen sulfite, potassium hydrogen sulfite, magnesium hydrogen sulfite, calcium hydrogen sulfite, and ammonium hydrogen sulfite. Among them, lithium hydrogen sulfite, sodium hydrogen sulfite or ammonium hydrogen sulfite having a high content of sulfite ions having a curing accelerating action is preferred.

[0030] The rust inhibitor can suppress the corrosion of the production equipment by the acid component in the aqueous binder. Examples of the rust inhibitor include thiourea-based compounds such as thiourea, thiosemicarbazide, N-phenylthiourea, o-tolylthiourea, N-methylthiourea, 1,3-dimethylthiourea, N,N'-diethylthiourea, 1,3-dibutylthiourea, tetramethylthiourea, 1,3-diphenyl-2-thiourea, 1,3-diisopropylthiourea, ethylene thiourea, 2-mercaptobenzothiazole, and trimethylthiourea. These can be used alone or in combination of two or more. Although alkanolamine may function as a rust inhibitor, when the aqueous binder contains alkanolamine, alkanolamine is not included in the rust inhibitor and is treated as a crosslinking agent.

[0031] Examples of the neutralizing agent include inorganic sulfates (such as ammonium sulfate) for neutralizing the alkali components eluted from inorganic fibers such as glass, and these can be used alone or in combination of two or more.

[0032] The content (in terms of solid content) of other additives in the aqueous binder is preferably 1 to 20 parts by mass with respect to a total of 100 parts by mass (in terms of solid content) of the polycarboxylic acid and the crosslinking agent.

[0033] In the aqueous binder of the present embodiment, the ratio of the total number of moles of the hydroxyl groups, amino groups, and imino groups of the polycarboxylic acid, crosslinking agent 1, and crosslinking agent 2 to the total number of moles of the carboxyl groups of the polycarboxylic acid, crosslinking agent 1, and crosslinking agent 2 ((hydroxyl group + amino group + imino group) / carboxyl group, hereinafter also referred to as "molar ratio 1") is 0.2 or more. When the molar ratio 1 is 0.2 or more, an aqueous binder with lower viscosity and less stickiness than conventional polycarboxylic acid-based binders is obtained. The molar ratio 1 is preferably 0.3 or more, more preferably 0.5 or more. The upper limit of the molar ratio 1 is not particularly limited, and for example, it may be 5.0 or less, 3.0 or less, or 1.0 or less. When the upper limit of the molar ratio 1 is 5.0 or less, an aqueous binder with higher adhesive strength tends to be obtained. When the crosslinking agent 2 contains lactone, the number of moles of the carboxyl group, hydroxyl group, amino group, and imino group in the hydroxycarboxylic acid before dehydration condensation to form lactone is used as the number of moles of the carboxyl group, hydroxyl group, amino group, and imino group in the lactone to calculate the molar ratio 1. In addition, the hydroxyl group in calculating the molar ratio 1 shall not include the hydroxyl group in the carboxyl group.

[0034] The aqueous binder of this embodiment has a ratio ((hydroxyl group + amino group + imino group) / carboxyl group, hereinafter also referred to as "molar ratio 2") of the total molar number of hydroxyl groups, amino groups and imino groups of crosslinking agent 1 and crosslinking agent 2 to the total molar number of carboxyl groups of crosslinking agent 1 and crosslinking agent 2, which is 6.0 or less. When the molar ratio 2 is 6.0 or less, an aqueous binder with lower viscosity and less stickiness than conventional polycarboxylic acid-based binders can be obtained. The molar ratio 2 is preferably 5.0 or less, more preferably 3.5 or less. The lower limit of the molar ratio 2 is not particularly limited, and for example, it may be 1.0 or more, may be 1.2 or more, or may be 1.5 or more. When the lower limit of the molar ratio 2 is 1.0 or more, an aqueous binder with higher adhesive strength tends to be obtained. When the crosslinking agent 2 contains a lactone, the molar ratio 2 is calculated using the number of moles of carboxyl groups, hydroxyl groups, amino groups and imino groups in the hydroxycarboxylic acid before dehydration condensation to form the lactone as the number of moles of carboxyl groups, hydroxyl groups, amino groups and imino groups in the lactone. In addition, the hydroxyl group in calculating the molar ratio 2 shall not include the hydroxyl group in the carboxyl group.

[0035] The form of the aqueous binder is not particularly limited, and examples include emulsions, colloidal dispersions, water-soluble compositions, and the like. An emulsion means one emulsified with an emulsifier different from the resin component (such as polycarboxylic acid) in the aqueous binder, for example, a surfactant. A colloidal dispersion means one in which the resin component is dispersed in water by the functional groups in the resin component. Generally, both emulsions and colloidal dispersions exhibit a milky white appearance. A water-soluble composition means one in which the resin component is dissolved in water, and the appearance is also transparent or nearly transparent.

[0036] As the form of the aqueous binder, as described below, since process control is easy, a water-soluble composition is more advantageous than an emulsion or a colloidal dispersion. That is, in an emulsion or a colloidal dispersion, the dispersed resin component (such as polycarboxylic acid) has properties of low solubility and swelling property with water. When the water as the medium volatilizes, it is easy to form a film. If the resin component in the aqueous binder forms a film before curing, the fluidity of the aqueous binder on the surface of the inorganic fiber is easily impaired. Not only is it impossible to obtain a homogeneous inorganic fiber heat-insulating and sound-absorbing material with an even adhesion amount of the aqueous binder, but there are also many parts lacking the binding by the aqueous binder between the inorganic fibers, and it may be difficult to maintain the shape as a product. Also, in a colloidal dispersion or an emulsion, once the water as the medium volatilizes to form a film, it is difficult to return to the aqueous material again. Therefore, if the aqueous binder adheres to the manufacturing equipment etc., cleaning becomes complicated and productivity tends to decrease.

[0037] On the other hand, when the aqueous binder is a water-soluble composition, film formation does not occur immediately even if water gradually volatilizes from the aqueous binder, so the above problems do not occur. Therefore, it is preferable to prepare the aqueous binder as a water-soluble composition.

[0038] Although there are the above circumstances, for an emulsion or a colloidal dispersion, it is also possible to use it without practical problems by using it under humid conditions or adjusting the moisture content. Therefore, which form of emulsion, colloidal dispersion, or water-soluble composition should be used can be appropriately determined according to the use environment of the aqueous binder.

[0039] The solid content of the aqueous binder is preferably 1 to 50% by mass, more preferably 45% by mass or less, and still more preferably 40% by mass or less. When the solid content is 1% by mass or more, since the amount of water is appropriate, the curing does not take too much time and good productivity can be maintained. When the solid content is 50% by mass or less, a decrease in the fluidity of the aqueous binder can be prevented. In this specification, the solid content refers to the components that do not volatilize when the aqueous binder is heated at 210°C for 20 minutes. The heating is carried out using SPHH-102 manufactured by Espec Corporation, with the opening degree of the exhaust damper set at 50%. The components other than the solid content (volatile components) are preferably water.

[0040] <Method for Reducing Stickiness of Aqueous Binder for Inorganic Fiber Heat Insulating and Sound Absorbing Material and Method for Producing Aqueous Binder for Inorganic Fiber Heat Insulating and Sound Absorbing Material> In this embodiment, the method for reducing the stickiness of an aqueous binder for an inorganic fiber heat insulating and sound absorbing material containing a polycarboxylic acid and a crosslinking agent for the polycarboxylic acid includes containing, as the crosslinking agent, (crosslinking agent 1) an alkanolamine and (crosslinking agent 2) a hydroxycarboxylic acid in which the carbon number of the portion other than the carboxyl group is 5 or less and / or a lactone obtained by dehydration condensation of the hydroxycarboxylic acid, and the ratio of the total number of moles of the hydroxyl group, amino group, and imino group of the polycarboxylic acid, crosslinking agent 1, and crosslinking agent 2 to the total number of moles of the carboxyl groups of the polycarboxylic acid, crosslinking agent 1, and crosslinking agent 2 is 0.2 or more, and the ratio of the total number of moles of the hydroxyl group, amino group, and imino group of the crosslinking agent 1 and crosslinking agent 2 to the total number of moles of the carboxyl groups of the crosslinking agent 1 and crosslinking agent 2 is 6.0 or less. However, when the crosslinking agent 2 contains a lactone, the number of moles of each functional group in the hydroxycarboxylic acid before dehydration condensation is used as the number of moles of each functional group in the lactone. Also, when expressing the above method from another aspect, it is a method for producing an aqueous binder for an inorganic fiber heat-insulating and sound-absorbing material containing a polycarboxylic acid with reduced stickiness and a cross-linking agent for the polycarboxylic acid, the method including a step of containing, as the cross-linking agent, (cross-linking agent 1) an alkanolamine and (cross-linking agent 2) a hydroxycarboxylic acid having 5 or less carbon atoms in a part other than the carboxyl group and / or a lactone obtained by dehydration condensation of the hydroxycarboxylic acid, and the ratio of the total number of moles of the hydroxyl group, amino group, and imino group of the polycarboxylic acid, cross-linking agent 1, and cross-linking agent 2 to the total number of moles of the carboxyl group of the polycarboxylic acid, cross-linking agent 1, and cross-linking agent 2 is 0.2 or more, and the ratio of the total number of moles of the hydroxyl group, amino group, and imino group of cross-linking agent 1 and cross-linking agent 2 to the total number of moles of the carboxyl group of cross-linking agent 1 and cross-linking agent 2 is 6.0 or less.

[0041] In the method for reducing the stickiness of the aqueous binder for the inorganic fiber heat-insulating and sound-absorbing material and the polycarboxylic acid and cross-linking agent used in the method for producing the aqueous binder for the inorganic fiber heat-insulating and sound-absorbing material, they have the characteristics of the polycarboxylic acid and cross-linking agent contained in the aqueous binder for the inorganic fiber heat-insulating and sound-absorbing material of the above-described present embodiment.

[0042] In the method for producing the aqueous binder for the inorganic fiber heat-insulating and sound-absorbing material of the present embodiment, the method of containing the cross-linking agent is not particularly limited, and a conventionally known method can be used. For example, an aqueous binder can be obtained by adding a cross-linking agent and, if necessary, other additives to a resin solution in which a polycarboxylic acid is dissolved in water, mixing them to obtain a water-soluble composition, and then diluting with water.

[0043] 〈Inorganic Fiber Heat-Insulating and Sound-Absorbing Material〉 The inorganic fiber heat-insulating and sound-absorbing material of the present embodiment includes inorganic fibers and a cured product of the above-described aqueous binder of the present embodiment that fixes (holds) the inorganic fibers. That is, the inorganic fiber heat-insulating and sound-absorbing material can be obtained by applying the above aqueous binder to the inorganic fibers and heating and curing the aqueous binder to form it. As the inorganic fiber, glass wool, rock wool, etc. that are used in ordinary heat insulating and sound absorbing materials can be used. As the method for fiberizing the inorganic fiber, for example, 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 and sound absorbing material may be used in its original form, or may be used after being covered with a skin material. As the skin material, for example, paper, a synthetic resin film, a metal foil film, a nonwoven fabric, a woven fabric, or a combination thereof can be used. The density of the inorganic fiber heat insulating and sound absorbing material may be the density used in ordinary heat insulating materials and sound absorbing materials, and is preferably 5 to 300 kg / m 3 is.

[0044] <Method for manufacturing inorganic fiber heat insulating and sound absorbing material> The inorganic fiber heat insulating and sound absorbing material of the present embodiment can be obtained by applying the aqueous binder of the present embodiment described above to the inorganic fiber and heating and curing the aqueous binder to form it. More specifically, for example, the molten inorganic raw material is fiberized by a fiberizing device, and immediately thereafter, the aqueous binder is applied to the inorganic fiber. Next, the inorganic fiber to which the aqueous binder is applied is deposited on a perforated conveyor to form an intermediate body for a bulky inorganic fiber heat insulating and sound absorbing material, and it is sent to a pair of upper and lower perforated conveyors or the like provided with intervals so as to have a desired thickness, and heated while being narrowly pressed to cure the aqueous binder to form an inorganic fiber heat insulating and sound absorbing material. If necessary, by covering with a skin material or the like and cutting to a desired width and length, an inorganic fiber heat insulating and sound absorbing material can be obtained.

[0045] Examples of the method for applying the aqueous binder to the inorganic fiber include a method of coating or spraying using a spray device or the like. The timing for applying the aqueous binder to the inorganic fiber may be after fiberization, and from the viewpoint of efficiently applying the aqueous binder, it is preferably applied immediately after fiberization. The application amount of the aqueous binder varies depending on the density and use of the inorganic fiber heat insulating and sound absorbing material, but based on the mass of the inorganic fiber heat insulating and sound absorbing material to which the aqueous binder is applied, it is preferably 0.5 to 30% by mass in terms of solid content, and more preferably 0.5 to 20% by mass.

[0046] As a method for heating inorganic fibers provided with an aqueous binder, for example, heating with a hot air oven can be mentioned. The heating temperature in the hot air oven can be, for example, 200 to 350°C. 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 and sound absorbing material.

Example

[0047] Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to the following examples as long as the gist thereof is not exceeded.

[0048] The measurement and evaluation methods used in the examples and comparative examples are as follows.

[0049] [Water solubility] Regarding the water solubility of the aqueous binder (solid content 35%), the aqueous binder was prepared while stirring at 400 RPM using a glass container, the stirring was stopped 30 minutes after the preparation, and the presence or absence of precipitates was visually confirmed at room temperature (25°C) for evaluation. A state where precipitates occur at a solid content of 35% is not preferable because it causes clogging of the binder liquid supply piping and nozzles during the production of the inorganic fiber heat insulating and sound absorbing material.

[0050] [Stickiness] (Sample preparation) The glass filter paper (manufactured by Advantec Toyo Co., Ltd., ADVANTEC GA-100, φ55 mm) was impregnated with the aqueous binder so that the solid content of the aqueous binder was 75% by mass with respect to the total mass of the glass filter paper and the solid content of the aqueous binder, and the aqueous binder was concentrated by heating at 130°C for 7 minutes. In Example 1, 2.14 g of a binder with a solid content of 35% was dropped onto 0.25 g of the glass filter paper with a pipette and impregnated throughout the glass filter paper. Samples were prepared in the same manner for the other examples. The concentration of the samples was carried out using SPHH-102 manufactured by Espec Co., Ltd. with the opening degree of the exhaust damper set at 50%. The heated samples were stored in a sealed container, cooled to room temperature, and taken out from the sealed container for use during measurement. (Probe Tack Test) Using the obtained samples, a probe tack test was carried out under the following measurement conditions. The probe tack test is a test method used to measure the adhesiveness and adhesion of an adhesive tape, and is also used to evaluate stickiness. Apparatus: Manufactured by Eihong Seiki Co., Ltd., Texture Analyzer TA-XT Plus Probe: Made of SUS, φ0.75in spherical probe Load cell: 5 kg Measurement conditions: Descending at 0.5 mm / sec. Pressing at 500 gf × 10 sec. Ascending at 10 mm / sec. Measurements were made on 6 samples for each level, and the median value of the maximum tack force (gf) was taken as the maximum tack force of the aqueous binder. The maximum tack forces of each example and comparative example were shown as relative values with the maximum tack force of Comparative Example 1 (a conventional polycarboxylic acid-based aqueous binder not containing crosslinking agent 2) taken as 100. A relative value of 60 or less indicates low viscosity and less stickiness, which is preferable.

[0051] The raw materials used in the examples and comparative examples are as follows.

[0052] [Polycarboxylic Acid] · Polyacrylic acid: Acrylic acid was radically polymerized using sodium hypophosphite as a chain transfer agent to obtain polyacrylic acid (weight average molecular weight 4700, acid value 708 mgKOH / g). The weight average molecular weight was measured using GPC (manufactured by Tosoh Corporation, "HLC-8420GPC") and two columns connected in series (manufactured by Tosoh Corporation, "TSKgel G3000PWXL"), with the column temperature at 40°C, the solvent as 0.2M phosphate buffer (pH 7.0), and the solvent flow rate at 0.5 mL / min. It was determined using a calibration curve obtained from the measurement of commercially available standard polyacrylic acid (created using the peak molecular weight of the standard polyacrylic acid). The acid value was determined as the value (mgKOH / g) in terms of the solid content of the polycarboxylic acid, which was obtained by neutralizing 3 g of a 50% aqueous solution of polycarboxylic acid with potassium hydroxide and using the mass of potassium hydroxide (mgKOH) required for neutralization.

[0053] [Crosslinking agent] [[Crosslinking agent 1]] · Diethanolamine · Triethanolamine [[Crosslinking agent 2]] · Lactic acid · Citric acid [[Other crosslinking agents]] · Salicylic acid · Polyethyleneimine · Triethylenetetramine

[0054] [Other additives] · Ammonium sulfate · γ-Aminopropyltriethoxysilane

[0055] [Example 1] Polyacrylic acid was dissolved in water to obtain a resin solution (solid content 46%). The resin solution and crosslinking agents (diethanolamine (crosslinking agent 1) and lactic acid (crosslinking agent 2)) were mixed so as to have the mass ratios shown in Table 1 to obtain a water-soluble composition. Further, with the total solid content of polyacrylic acid and crosslinking agents being 100 parts by mass, 8 parts by mass of ammonium sulfate as a neutralizing agent and 0.6 parts by mass of γ-aminopropyltriethoxysilane as a silane coupling agent were added, and the water-soluble composition was diluted with water so that the solid content became 35% to obtain an aqueous binder. These formulations were carried out while stirring at 400 RPM in a glass container. Note that the mass ratios of the respective components are values in terms of the solid content. The evaluation results of the aqueous binder are shown in Table 1. Also, the following molar ratios 1 and 2 (composition) obtained from the ratios of the respective components are shown in Table 1 Molar ratio 1 = (Total number of moles of hydroxyl groups, amino groups and imino groups of polycarboxylic acid, crosslinking agent 1 and crosslinking agent 2) / (Total number of moles of carboxyl groups of polycarboxylic acid, crosslinking agent 1 and crosslinking agent 2) Molar ratio 2 = (total number of moles of hydroxyl, amino, and imino groups in crosslinking agent 1 and crosslinking agent 2) / (total number of moles of carboxyl groups in crosslinking agent 1 and crosslinking agent 2)

[0056] [Examples 2 to 6, Comparative Examples 1 to 6] An aqueous binder was obtained in the same manner as in Example 1, except that the proportions of the respective components were as shown in Table 1. Comparative Examples 1, 2, and 3 are conventional polycarboxylic acid-based aqueous binders produced with reference to the compositions of the examples in Patent Documents 7, 8, and 9, respectively. The salicylic acid used in Comparative Example 6 is a crosslinking agent having 6 carbon atoms other than the carboxyl group. The mass ratio of each component is a value in terms of solid content. In the same manner as in Example 1, the evaluation results of each aqueous binder and Molar ratios 1 and 2 (composition) are shown in Table 1. For comparative examples using other crosslinking agents, Molar ratio 1' and Molar ratio 2' were determined by the following formulas instead of Molar ratio 1 and Molar ratio 2. Molar ratio 1' = (total number of moles of hydroxyl, amino, and imino groups in polycarboxylic acid, crosslinking agent 1, crosslinking agent 2, and other crosslinking agents) / (total number of moles of carboxyl groups in polycarboxylic acid, crosslinking agent 1, crosslinking agent 2, and other crosslinking agents) Molar ratio 2' = (total number of moles of hydroxyl, amino, and imino groups in crosslinking agent 1, crosslinking agent 2, and other crosslinking agents) / (total number of moles of carboxyl groups in crosslinking agent 1, crosslinking agent 2, and other crosslinking agents) Note that in Comparative Example 6, there were many precipitates, and the measurement of the maximum tack force was not performed. Adhesion strength is cited as another performance required for the aqueous binder for the inorganic fiber heat insulating and sound absorbing material. However, Examples 1 to 6 and Comparative Examples 1 to 5 had sufficient strength.

[0057]

Table 1

Industrial Applicability

[0058] The aqueous binder for the inorganic fiber heat insulating and sound absorbing material of the present invention has less stickiness than conventional polycarboxylic acid-based binders and can be suitably used for producing inorganic fiber heat insulating and sound absorbing materials.

Claims

1. An aqueous binder for an inorganic fiber heat insulating and sound absorbing material, comprising a polycarboxylic acid and a crosslinking agent for the polycarboxylic acid, The crosslinking agent (Crosslinking agent 1) an alkanolamine, (Crosslinking agent 2) containing a hydroxycarboxylic acid having 5 or less carbon atoms other than the carboxyl group and / or a lactone obtained by dehydration condensation of the hydroxycarboxylic acid, The polycarboxylic acid includes a polycarboxylic acid having a weight average molecular weight of 1,000 to 20,000 and an acid value of 500 to 900 mgKOH / g, a ratio of the total number of moles of hydroxyl groups, amino groups, and imino groups of the polycarboxylic acid, the crosslinking agent 1, and the crosslinking agent 2 to the total number of moles of carboxyl groups of the polycarboxylic acid, the crosslinking agent 1, and the crosslinking agent 2 is 0.2 or more; The ratio of the total number of moles of hydroxyl groups, amino groups, and imino groups of the crosslinking agent 1 and the crosslinking agent 2 to the total number of moles of carboxyl groups of the crosslinking agent 1 and the crosslinking agent 2 is 6.0 or less. An aqueous binder for an inorganic fiber heat insulating and sound absorbing material, comprising: When the crosslinking agent 2 contains a lactone, the number of moles of each functional group in the hydroxycarboxylic acid before dehydration condensation is defined as the number of moles of each functional group in the lactone.

2. The present invention relates to a heat insulating and sound absorbing material for an inorganic fiber. An inorganic fiber heat insulating and sound absorbing material.

3. A method for reducing stickiness of an aqueous binder for an inorganic fiber heat insulating and sound absorbing material, the method comprising the steps of: As the crosslinking agent (Crosslinking agent 1) an alkanolamine, (Crosslinking agent 2) A crosslinking agent containing a hydroxycarboxylic acid having 5 or less carbon atoms in a portion other than a carboxyl group and / or a lactone obtained by dehydration condensation of the hydroxycarboxylic acid, a ratio of the total number of moles of hydroxyl groups, amino groups, and imino groups of the polycarboxylic acid, the crosslinking agent 1, and the crosslinking agent 2 to the total number of moles of carboxyl groups of the polycarboxylic acid, the crosslinking agent 1, and the crosslinking agent 2 is 0.2 or more; The ratio of the total number of moles of hydroxyl groups, amino groups, and imino groups of the crosslinking agent 1 and the crosslinking agent 2 to the total number of moles of carboxyl groups of the crosslinking agent 1 and the crosslinking agent 2 is 6.0 or less. A method comprising: When the crosslinking agent 2 contains a lactone, the number of moles of each functional group in the hydroxycarboxylic acid before dehydration condensation is defined as the number of moles of each functional group in the lactone.

4. A method for producing an aqueous binder for an inorganic fiber heat insulating and sound absorbing material, which contains a polycarboxylic acid and a crosslinking agent for the polycarboxylic acid and has reduced stickiness, comprising: As the crosslinking agent (Crosslinking agent 1) an alkanolamine, (Crosslinking agent 2) A step of incorporating a crosslinking agent containing a hydroxycarboxylic acid having 5 or less carbon atoms in a portion other than a carboxyl group and / or a lactone obtained by dehydration condensation of the hydroxycarboxylic acid, a ratio of the total number of moles of hydroxyl groups, amino groups, and imino groups of the polycarboxylic acid, the crosslinking agent 1, and the crosslinking agent 2 to the total number of moles of carboxyl groups of the polycarboxylic acid, the crosslinking agent 1, and the crosslinking agent 2 is 0.2 or more; The ratio of the total number of moles of hydroxyl groups, amino groups, and imino groups of the crosslinking agent 1 and the crosslinking agent 2 to the total number of moles of carboxyl groups of the crosslinking agent 1 and the crosslinking agent 2 is 6.0 or less. A manufacturing method comprising: When the crosslinking agent 2 contains a lactone, the number of moles of each functional group in the hydroxycarboxylic acid before dehydration condensation is defined as the number of moles of each functional group in the lactone.

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