JP6407674B2 - Nonionic polyhydric alcohol-containing binder - Google Patents

Description

  The present invention relates to a binder containing a polyacrylic acid polymer and a nonionic polyhydric alcohol. More specifically, the present invention relates to a binder containing a polyacrylic acid polymer and a nonionic polyhydric alcohol, which is useful as a binder for glass fibers and powdered glass.

  A heat-resistant molded body obtained by attaching a binder to glass fiber or the like and molding it into a mat shape is widely used as a heat insulating material for a residence, a warehouse, an apparatus or an appliance. As the binder, a phenol-formaldehyde binder is widely used. However, the phenol-formaldehyde binder has a problem in that unreacted formaldehyde remains in the molded body and formaldehyde is released after construction of a house or the like. Therefore, binders that do not release formaldehyde have been studied.

  For example, U.S. Patent No. 6,057,049 includes (a) a polyacid containing at least two carboxylic acid groups, acid anhydride groups, or salts thereof; (b) a polyol containing at least two hydroxyl groups; c) a phosphorus (III) -containing accelerator; and the ratio of the number of equivalents of the carboxylic acid group, acid anhydride group, or salt thereof to the equivalents of the hydroxyl group is about 1 / 0.0. Disclosed is a curable aqueous composition wherein the carboxylic acid group, anhydride group, or salt thereof is neutralized to a range of about 35% or less with a non-volatile base. Has been. Patent Document 1 discloses that the composition can be used as a binder for nonwoven fabric made of glass fibers or other heat-resistant fibers.

  For example, Patent Document 2 discloses that (co) polymer (A) having at least two carboxyl groups and / or latent carboxyl groups, polyol (B) having at least two hydroxyl groups, Lewis acid (C1) And at least one selected from the group consisting of proton acids (C2), a curing catalyst (C) containing no phosphorus atom, and water, derived from the carboxyl group and latent carboxyl group in (A) An aqueous binder for mineral fibers (X) in which the ratio (COOH / OH) of the total number of moles of carboxyl groups and the number of moles of hydroxyl groups in (B) is 0.5 to 2.0 is disclosed. . In Patent Document 2, the above-mentioned aqueous binder for mineral fibers includes (1) excellent adhesion of mineral fibers, (2) excellent water resistance and hydrolysis resistance, and (3) mineral fibers formed by bonding with the binder. It is disclosed that the mat is excellent in compressibility and (4) does not contain formaldehyde.

JP-A-6-184285 JP 2013-136864 A

  As described above, various binders such as glass fibers containing a compound having at least two carboxyl groups and a polyol having at least two hydroxyl groups have been proposed. However, the strength of glass fibers and the like treated with these binders cannot be said to be sufficiently satisfactory, and there has been a demand for improvement.

  The present invention has been made by paying attention to the above circumstances, and expresses excellent bonding strength of glass fibers and powdered glass (giving good strength to a bonded body of glass fibers and powdered glass). The object is to provide possible binders.

  As a result of intensive studies, the present inventors have found that the binder contains a polyacrylic acid polymer and a nonionic polyhydric alcohol at a predetermined ratio, so that the strength of the glass fiber or powder glass binder is increased. Was found to be satisfactory, and the present invention was completed based on these findings.

  That is, the present invention is a binder comprising (i) a polyacrylic acid polymer and (ii) a nonionic polyhydric alcohol, wherein the nonionic polyhydric alcohol is a compound having 3 or more carbon atoms. And a nonionic polyhydric alcohol content of 7 mol% or more and 40 mol% or less with respect to 100 mol% of the carboxyl group contained in the polyacrylic acid polymer.

  By treating with the bonded body of the present invention, glass fibers and powdered glass can exhibit good strength. Therefore, the binder of the present invention can be usefully used as, for example, a binder for residential heat insulating materials.

Hereinafter, the present invention will be described in detail.
A combination of two or more preferred embodiments of the present invention described below is also a preferred embodiment of the present invention.

[Acrylic acid polymer]
The binder of the present invention includes an acrylic acid polymer.
In the present invention, the “acrylic acid polymer” refers to a polymer containing a structural unit derived from acrylic acid (salt). The “structural unit derived from acrylic acid (salt)” means a structural unit having a structure formed by polymerization of acrylic acid (salt). For example, in the case of acrylic acid (CH2═CH—COOH), acrylic The structural unit derived from an acid is represented by —CH ₂ —CH (COOH) —.
The “structural unit derived from acrylic acid (salt)” may be a structural unit having the same structure as that formed by polymerizing acrylic acid (salt), and actually polymerizes acrylic acid (salt). It may be a structural unit formed by a method other than the above.
The above “acrylic acid (salt)” refers to acrylic acid and acrylate. Examples of the salt in the acrylic salt include metal salts, ammonium salts, and organic amine salts. Examples of the metal salts include alkali metal salts such as sodium salts and potassium salts; alkaline earth metal salts such as calcium salts; aluminum Examples thereof include transition metal salts such as salts and iron salts. Examples of the organic amine salt include salts of alkylamines such as methylamine and n-butylamine; alkanolamines such as monoethanolamine, diethanolamine, triethanolamine and dipropanolamine; polyamines such as ethylenediamine and diethylenetriamine; .

  The acrylic acid polymer that is an essential component of the binder of the present invention (hereinafter referred to as “the acrylic acid polymer of the present invention”) is derived from all monomers of the structural unit derived from acrylic acid (salt). It is preferable to have 60 mol% or more and 100 mol% or less with respect to 100 mol% of the structural unit (the structural unit derived from the above acrylic acid (salt) and the structural unit derived from the other monomer described later), More preferably, it has 80 mol% or more and 100 mol% or less, and more preferably 90 mol% or more and 100 mol% or less. The acrylic polymer of the present invention includes a structural unit derived from acrylic acid (salt) in the above range, so that the binder of the present invention is used as a binder for glass fiber or powder glass. It tends to improve the strength of the body.

  Although the acrylic acid polymer of the present invention has an acid group (for example, a carboxylic acid (salt) group contained in a structural unit derived from acrylic acid (salt)), the acrylic acid polymer of the present invention includes It is preferable that 50-100 mol% is an unneutralized acid group (namely, acid type acid group) with respect to 100 mol% of acid groups contained. More preferably, it is 55-100 mol%, More preferably, it is 60-100 mol%. By being the said range, it exists in the tendency for the intensity | strength of the to-be-bonded body at the time of using the binder of this invention for the binder of glass fiber or powder glass to improve.

The acrylic acid polymer of the present invention may have a structural unit derived from a monomer other than acrylic acid (salt) (hereinafter also referred to as “other monomer”).
The other monomer is not particularly limited as long as it is a monomer other than acrylic acid (salt). Specifically, methacrylic acid, crotonic acid, α-hydroxyacrylic acid, α-hydroxymethyl Unsaturated monocarboxylic acids such as acrylic acid and derivatives thereof, and salts thereof; Unsaturated dicarboxylic acids such as fumaric acid, maleic acid, methylene glutaric acid, itaconic acid, and salts thereof (mono- or di-salts) Sulfonic acid monomers such as 3-allyloxy-2-hydroxypropanesulfonic acid, (meth) allylsulfonic acid, isoprenesulfonic acid, vinylsulfonic acid, styrenesulfonic acid and salts thereof; vinyl Pyridine, vinylimidazole, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dimethylaminopropyl acrylate Amino group methacrylates such as acrylate, aminoethyl methacrylate, diallylamine, diallyldimethylamine, and quaternized compounds and salts thereof; N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, N-vinyl-N- N-vinyl monomers such as methylformamide, N-vinyl-N-methylacetamide, N-vinyloxazolidone; amide monomers such as (meth) acrylamide, N, N-dimethylacrylamide, N-isopropylacrylamide; 3 -Hydroxyl groups such as (meth) allyloxy-1,2-dihydroxypropane, 3-allyloxy-1,2-dihydroxypropane, (meth) allyl alcohol, isoprenol, hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate, etc. Monomer; top Polyalkylene glycol monomers having a structure in which alkylene oxide is added to unsaturated alcohol monomers; (meth) acrylic acids such as butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate Alkyl ester monomers; unsaturated glycidyl compounds such as (meth) allyl glycidyl ether and glycidyl (meth) acrylate; alcohol added to unsaturated glycidyl compounds such as 1-allyloxy-3-butoxypropan-2-ol Monomers having such a structure; vinyl aryl monomers such as styrene, indene and vinylaniline; alkenes such as isobutylene and octene; and vinyl carboxylates such as vinyl acetate and vinyl propionate. Moreover, when using the said other monomer, 1 type may be used independently or 2 or more types may be used together. As said salt, the salt similar to the salt in the said acrylic acid (salt) is illustrated.

In the present invention, the structural unit derived from the other monomer is a structural unit formed by polymerization of the other monomer, specifically, the carbon-carbon double bond of the other monomer. Is a structure with a single bond. For example, when the other monomer is butyl acrylate (CH ₂ ═CHCOOC ₄ H ₉ ), the structural unit derived from the other monomer is —CH ₂ —CH (COOC ₄ H ₉ ) —. Can be represented.

The acrylic acid polymer of the present invention may have a structural unit derived from another monomer of 0 mol% or more and 40 mol% or less with respect to 100 mol% of the structural unit derived from all monomers. Preferably, it is 0 mol% or more and 20 mol% or less, more preferably 0 mol% or more and 10 mol% or less. The polymer of the present invention can have one or more structural units derived from other monomers.
From the viewpoint of improving the storage stability of the binder of the present invention, the content of the structural unit derived from the hydroxyl group-containing monomer contained in the acrylic acid polymer of the present invention is derived from all monomers. The amount is preferably 20 mol% or less, more preferably 10 mol or less, relative to 100 mol% of the structural unit.

  Each structural unit in the polymer of the present invention may be present randomly, or may be present regularly such as in a block form.

Since the acrylic acid polymer of the present invention has a tendency to improve the strength of the bonded body when the binder of the present invention is used as a binder for glass fiber or powder glass, it tends to suppress moisture absorption deterioration. The average molecular weight is preferably 500 or more and 100,000 or less, preferably 1,500 or more and 15,000 or less, and more preferably 2,000 or more and 10,000 or less.
In addition, the said weight average molecular weight can be measured with the measuring method mentioned later.

  The acrylic acid polymer of the present invention is preferably produced by including a step of polymerizing acrylic acid (salt) and, if necessary, other monomers. In the above step, 60% of acrylic acid (salt) is used with respect to 100 mol% of the total amount of acrylic acid (salt) and other monomers (hereinafter also referred to as “total monomers”). It is preferable to set it as -100 mol%, It is more preferable to set it as 80-100 mol%, It is more preferable to set it as 90-100 mol%. The amount of other monomers used in the above step is preferably 0 to 40 mol%, more preferably 0 to 20 mol%, based on 100 mol% of the total amount of all monomers used. Preferably, it is more preferably 0 to 10 mol%.

  The polymerization in the polymerization step is performed by various conventionally known methods such as solution polymerization method, bulk polymerization, suspension polymerization method, reverse phase suspension polymerization method, cast polymerization method, thin film polymerization method, spray polymerization method, etc. Can be adopted. Although not particularly limited, solution polymerization is preferred. The polymerization step can be carried out either batchwise or continuously.

In the polymerization step, a polymerization initiator is preferably used when the polymerization is performed. Examples of the polymerization initiator include hydrogen peroxide; persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate; dimethyl 2,2′-azobis (2-methylpropionate), 2,2′- Azobis (isobutyronitrile), 2,2′-azobis (2-methylpropionamidine) dihydrochloride, 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate , 2,2′-azobis [2- (2-imidazolin-2-yl) propane], 2,2′-azobis (1-imino-1-pyrrolidino-2-methylpropane) dihydrochloride, etc. An organic peroxide such as benzoyl peroxide, lauroyl peroxide, peracetic acid, di-t-butyl peroxide, cumene hydroperoxide and the like is preferable. Of these polymerization initiators, hydrogen peroxide and persulfate are preferable, and persulfate is most preferable. These polymerization initiators may be used alone or in the form of a mixture of two or more.
The amount of the polymerization initiator used is preferably 0.1 g or more and 10 g or less, more preferably 0.1 g or more and 7 g or less with respect to 1 mol of the monomer (total monomer) used. More preferably, it is 0.1 g or more and 5 g or less.

In the polymerization step, a chain transfer agent may be used as necessary. Specific examples of chain transfer agents include thiol chain transfer agents such as mercaptoethanol, thioglycolic acid, mercaptopropionic acid, and n-dodecyl mercaptan; halogens such as carbon tetrachloride, methylene chloride, bromoform, and bromotrichloroethane. Secondary alcohols such as isopropanol and glycerin; hypophosphorous acid (salts) such as hypophosphorous acid and sodium hypophosphite (including hydrates thereof); phosphorous acid and sodium phosphite Phosphorous acid (salt) such as sodium sulfite, potassium sulfite and the like; bisulfite (salt) such as sodium hydrogen sulfite and potassium hydrogen sulfite; dithionic acid (salt) such as sodium dithionite; And pyrosulfurous acid (salt) such as potassium sulfite. The chain transfer agent may be used alone or in the form of a mixture of two or more.
The amount of the chain transfer agent used is preferably 0 g or more and 20 g or less, more preferably 1 g or more and 15 g or less, with respect to 1 mol of the monomer (total monomer) used. More preferably, it is 1 g or more and 10 g or less.

In the polymerization step, heavy metal ions may be used for the purpose of promoting the reaction. In the present invention, the heavy metal ion means a metal ion having a specific gravity of 4 g / cm 3 or more. By using heavy metal ions, the amount of polymerization initiator used can be reduced. The heavy metal ions are not particularly limited as long as they are included in the form of ions. However, it is preferable to use a method using a solution in which a heavy metal compound is dissolved because the handleability is excellent. Examples of the heavy metal compound include molle salt (Fe (NH ₄ ) ₂ (SO ₄ ) ₂ · 6H ₂ O), ferrous sulfate / pentahydrate, ferrous chloride, ferric chloride, manganese chloride, and the like. Illustrated.
The amount of the heavy metal ion used is preferably 0 ppm or more and 100 ppm or less, and more preferably 0 ppm or more and 50 ppm or less with respect to the total amount of the polymerization reaction solution.

The polymerization step preferably uses a solvent. The solvent preferably contains water, more preferably contains 50% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, based on the total amount of the solvent. Solvents usable in the polymerization step include water; lower alcohols such as methanol, ethanol and isopropyl alcohol; lower ketones such as acetone, methyl ethyl ketone and diethyl ketone; ethers such as dimethyl ether and dioxane; amides such as dimethylformaldehyde. Kind. These solvents may be used alone or in the form of a mixture of two or more.
As a usage-amount of a solvent, 40-200 mass% is preferable with respect to 100 mass% of monomers. More preferably, it is 45 mass% or more, More preferably, it is 50 mass% or more. Moreover, More preferably, it is 180 mass% or less, More preferably, it is 150 mass% or less. If the amount of the solvent used is less than 40% by mass, the molecular weight of the resulting polymer may be increased. If it exceeds 200% by mass, the concentration of the obtained polymer will be low, and the cost for storage and the like will be high. There is a risk.

The polymerization in the polymerization step is usually preferably performed at 0 ° C. or higher, and preferably 150 ° C. or lower. More preferably, it is 40 degreeC or more, More preferably, it is 60 degreeC or more, Most preferably, it is 80 degreeC or more. Moreover, More preferably, it is 120 degrees C or less, More preferably, it is 110 degrees C or less.
The polymerization temperature does not necessarily need to be kept almost constant in the polymerization reaction. For example, the polymerization is started from room temperature, the temperature is raised to a set temperature with an appropriate temperature increase time or rate, and then the set temperature is increased. You may make it hold | maintain and you may carry out temperature fluctuation (temperature rise or temperature fall) with time during a polymerization reaction according to dripping methods, such as a monomer component and an initiator.

  The polymerization time in the polymerization step is not particularly limited, but is preferably 30 to 420 minutes, more preferably 45 to 390 minutes, still more preferably 60 to 360 minutes, and most preferably 90 to 300 minutes. . In the present invention, “polymerization time” represents the time during which a monomer is added unless otherwise specified.

  In the polymerization step, the neutralization rate of the acid groups contained in the monomer during polymerization (number of moles of neutralized acid groups / (number of moles of neutralized acid groups + unneutralized acid groups) Is preferably 0% or more and 30% or less, and more preferably 0% or more and 20% or less.

  The pressure in the reaction system in the polymerization step may be any of normal pressure (atmospheric pressure), reduced pressure, and increased pressure, but in terms of molecular weight of the resulting polymer, the reaction may be performed under normal pressure or reaction. It is preferable to carry out under pressure while the system is sealed. Moreover, it is preferable to carry out under a normal pressure (atmospheric pressure) at the point of equipment, such as a pressurization apparatus, a pressure reduction apparatus, a pressure-resistant reaction container, and piping. The atmosphere in the reaction system may be an air atmosphere or an inert atmosphere. For example, the inside of the system may be replaced with an inert gas such as nitrogen before the start of polymerization.

  The acrylic acid polymer of the present invention is optional, but may be produced by including steps other than the polymerization step. For example, an aging step, a neutralization step, a deactivation step of a polymerization initiator or a chain transfer agent, a dilution step, a drying step, a concentration step, a purification step, and the like can be mentioned.

[Nonionic polyhydric alcohol]
The binder of the present invention contains a nonionic polyhydric alcohol as an essential component. The nonionic property means that the molecule does not have an anionic group such as a carboxylic acid group, a sulfonic acid group or a phosphoric acid group, or a cationic group such as an amino group or a quaternary amine group. When the binder of the present invention contains a nonionic polyhydric alcohol, the strength of the bonded body of glass fiber or powder glass can be improved.
The nonionic polyhydric alcohol has a main role of acting as a crosslinking agent for the acrylic acid polymer of the present invention in the binder of the present invention. However, since the polyhydric alcohol is nonionic, The storage stability tends to be improved by moderately interacting with the polymer of the present invention at the time of storage or crosslinking reaction of the invention, and the strength of the glass fiber or powder glass binder is remarkably improved. This is thought to be one of the reasons for this tendency.

  The nonionic polyhydric alcohol (hereinafter also referred to as “polyhydric alcohol of the present invention”), which is an essential component of the binder of the present invention, is used when the binder of the present invention is used as a binder for glass fibers or powdered glass. In view of the fact that the strength of the bonded body tends to be significantly improved, a compound having 3 or more carbon atoms is preferable. The reason why the above effect is obtained when the nonionic polyhydric alcohol contains 3 or more carbon atoms is not clear, but the nonionic polyhydric alcohol functions as a crosslinking agent for the acrylic acid polymer of the present invention. In this case, hydrolysis resistance is improved by making the vicinity of the ester bond as a crosslinking point relatively hydrophobic, and in the case of a polyhydric alcohol having a large distance between hydroxyl groups, the degree of freedom of the crosslinked chain is maintained. This is thought to be due to the fact that this is possible.

Examples of the polyhydric alcohol include bivalent alcohols (alcohols having two hydroxyl groups in the molecule) such as propanediol, butanediol, pentanediol, diethylene glycol, triethylene glycol, and polyalkylene glycol; glycerin, polyglycerin, erythritol, Examples include trivalent or higher alcohols (alcohol having three or more hydroxyl groups in the molecule) such as xylitol and sorbitol. A compound in which a part of hydroxyl groups of the trivalent or higher alcohol is esterified can also be used as the polyhydric alcohol as long as it has two or more hydroxyl groups in the molecule. The binder of the present invention may contain only one kind of polyhydric alcohol or two or more kinds. The polyhydric alcohol is preferably a dihydric alcohol and preferably a dihydric alcohol having 3 to 10 carbon atoms because the strength of the bonded body of glass fiber or powder glass tends to be further improved. More preferably, a compound represented by HO— (RO) _n —H (wherein R is a hydrocarbon having 3 to 10 carbon atoms, and n represents a number of 1 or more), propanediol, butane Diol and pentanediol are more preferable, and 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentanediol are particularly preferable.

The polyhydric alcohol is preferably a water-soluble polyhydric alcohol. Here, water-soluble means that the solubility in water (g number dissolved in 100 g of water) at 20 ° C. is 3 g / 100 g-H ₂ O or more.

  The polyhydric alcohol has a tendency to further improve the strength of the bonded body of glass fiber or powdered glass. Therefore, the molecular weight is preferably 1000 or less, more preferably 500 or less, and 300 or less. Is particularly preferred.

[Binder of the present invention]
The binder of the present invention essentially contains a nonionic polyhydric alcohol and the acrylic acid polymer of the present invention.
In the binder of the present invention, the polyhydric alcohol of the present invention is 7 mol% or more and 40 mol% with respect to 100 mol% of the carboxyl group contained in the acrylic acid polymer of the present invention contained in the binder of the present invention. It is preferably contained in an amount of 7 mol% or more and 30 mol% or less, more preferably 10 mol% or more and 30 mol% or less. By containing in the said range, it exists in the tendency for the intensity | strength of the coupling | bonding body of glass fiber or powder glass to improve notably.
The binder of the present invention preferably contains 25 to 93% by mass, more preferably 30 to 93% by mass, and more preferably 35 to 90% by mass of the acrylic acid polymer of the present invention with respect to 100% by mass of the binder. It is further preferable to include it. By containing in the said range, it exists in the tendency which the intensity | strength of the coupling | bonding body of glass fiber or powder glass improves more.

  Further, the hydroxyl group contained in the polyhydric alcohol contained in the binder of the present invention is 14 mol% or more and 80 mol relative to 100 mol% of the carboxyl group contained in the acrylic acid polymer contained in the binder of the present invention. % Or less, more preferably 14 mol% or more and 60 mol% or less, and particularly preferably 20 mol% or more and 60 mol% or less.

  The binder of the present invention may contain only the nonionic polyhydric alcohol and the acrylic acid polymer of the present invention, but when the binder of the present invention is used as a binder for glass fibers or powdered glass. Since the mechanical strength of the bonded body tends to be further improved, a phosphorus-containing compound may be included. The phosphorus compound is considered to have the effect of promoting the crosslinking of the acrylic acid polymer of the present invention.

  Phosphorus-containing compounds include acid groups such as hypophosphorous acid (salt), phosphorous acid (salt), phosphoric acid (salt), pyrophosphoric acid (salt), polyphosphoric acid (salt), and organic phosphoric acid (salt) Examples of the compound (including these hydrates); organophosphorus compounds such as trimethylphosphine, triphenylphosphine, triphenylphosphine oxide; When the binder of the present invention contains a phosphorus-containing compound, these may contain one kind or two or more kinds. Examples of the salt include those described above. The content of the phosphorus-containing compound in the binder of the present invention is preferably 0 to 20% by mass, more preferably 0 with respect to 100% by mass of the polymer (the polymer of the present invention) contained in the binder of the present invention. 0.1 to 10% by mass, more preferably 0.5 to 7% by mass.

The binder of the present invention may contain a curing accelerator other than the phosphorus-containing compound.
Curing accelerators other than phosphorus-containing compounds include proton acids [sulfuric acid, carboxylic acid, carbonic acid, etc.] and salts thereof [metal (alkali metal, alkaline earth metal, transition metal, 2B group, 4A group, 4B group, 4B group, 5B Group, etc.) salts, ammonium salts, etc.], metal (above) oxides, chlorides, hydroxides, alkoxides, etc., which may be used alone or in combination of two or more. The binder of this invention may contain 0-20 mass% of hardening accelerators other than the said phosphorus containing compound, for example.

The binder of the present invention may contain a solvent. The solvent may be an organic solvent, but preferably contains water, and 50% by mass or more is preferably water based on the total amount of the solvent.
The binder of the present invention preferably contains 0 to 75% by mass, more preferably 30 to 70% by mass, and 30 to 60% by mass of the solvent with respect to 100% by mass of the binder of the present invention. Further preferred.

[Use of the binder of the present invention]
The binder of the present invention includes inorganic fibers such as glass fibers, rock wool and carbon fibers; inorganic particles (inorganic powders) such as glass particles and mineral particles; organic fibers such as wool, cellulose, hemp, nylon and polyester; It can be used as a binder for organic particles such as nylon fine particles and polyester fine particles (organic powder); Preferably, it can be used as a binder for glass fibers or powdered glass.

[Method of using the binder of the present invention]
The treatment with the binder of the present invention requires a step of bringing the binder of the present invention into contact with a target substance (bonded substance) such as glass fiber or powdered glass. When the binder of the present invention contains a solvent, the above step is carried out as it is or after adjusting the concentration or the like as desired, and (i) the binder of the present invention is impregnated, or (ii) ) It is preferable to carry out by spraying the binder of the present invention on the substance to be bound. In the case where the binder of the present invention does not contain a solvent, the binder of the present invention may be heated and melted to be brought into contact with the substance to be bonded. Since it tends to be easy, it is preferable to carry out the above (i) or (ii) by dissolving in a solvent.
Among these, since it is easy to adjust the addition amount of the binder of the present invention to the bound substance, the above (i
i) is preferred.
In the step of bringing the binder of the present invention into contact with the bound substance, the amount of the binder of the present invention added to the bound substance is such that the solid content of the binder of the present invention is 100% by mass of the bound substance. It is preferably 1 to 40% by mass, more preferably 1 to 30% by mass, and further preferably 1 to 15% by mass. When the binder of the present invention is used in the above range, the mechanical strength of the bonded body tends to be improved.
The “addition amount of the binding agent of the present invention to the substance to be bonded in the step of contacting with the substance to be bonded” means that in step (i) above, the substance actually adheres to the substance to be bonded after impregnating the substance to be bonded. In the above step (ii), it means the amount of the binder that actually adheres to the bound substance after being sprayed on the bound substance.

The treatment with the binder of the present invention preferably includes a step of heat-treating the bonded body obtained in the step of contacting. By performing the heat treatment, the crosslinking reaction is promoted and the strength of the bonded body tends to be improved.
The heat treatment step is preferably performed at 100 to 400 ° C, more preferably 120 to 350 ° C, and further preferably 150 to 300 ° C.

When the binder of this invention contains a solvent, the process by the binder of this invention may include the process of drying the to-be-coupled body obtained at the process made to contact. The drying step may be performed under normal pressure or under reduced pressure. When drying is performed by heating, the conditions are the same as those in the heat treatment step.

  When the binder of this invention contains a solvent, the process by the binder of this invention may include the process of curing the to-be-coupled body obtained at the process made to contact.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples.

<Measurement conditions of weight average molecular weight>
Device: Tosoh HLC-8320GPC
Detector: RI
Column: Tosoh TSK-GEL G3000PWXL
Column temperature: 35 ° C
Flow rate: 0.5 ml / min
Calibration curve: POLY SODIUM ACRYLATE STANDARD
Eluent: A solution obtained by diluting a mixture of sodium dihydrogen phosphate 12 hydrate / disodium hydrogen phosphate dihydrate (34.5 g / 46.2 g) to 5000 g with pure water.

<Method for measuring solid content of binder>
The binder was left to dry for 60 minutes in an oven heated to 150 ° C. The solid content (%) was calculated from the weight change before and after drying.

<Content analysis of phosphorus-containing compounds (ion chromatography analysis)>
The content of the phosphorus-containing compound was analyzed by ion chromatography under the following conditions.
Apparatus: 762 Interface manufactured by Metrohm
Detector: 732 IC Detector manufactured by Metrohm
Ion analysis method: Suppressor method Column: Shodex IC SI-90 4E
Guard column: Shodex SI-90 G
Column temperature: 40 ° C
Eluent: NaHCO ₃ water (2 g diluted to 2000 g with water)
Flow rate: 1.0 mL / min.

<Creation of test piece for cured binder>
(I) Add water to the binder to adjust the solid content to 35%.
(Ii) To the glass beads having a particle size of 0.35 to 0.50 mm, add the binder obtained in (i) above so that the binder solid content is 7.5% of the weight of the glass beads. Mix.
(Iii) The mold obtained in (ii) is pressed into a 140 mm × 20 mm × 5 mm mold that has been subjected to mold release treatment, molded, dried in an oven at 200 ° C. for 30 minutes, then transferred to a desiccator and cooled for 30 minutes. Get a piece.

<Mechanical strength of specimen>
According to JISK7171, the bending strength was measured at a test speed of 2 mm / min. The bending strength of three test pieces was measured, and the average value was calculated.

<Production Example 1>
A 2.5-liter SUS separable flask equipped with a reflux condenser, a stirrer (paddle blade), and a thermometer was charged with 168.0 g of pure water (initial charge), and the temperature was raised to the boiling point with stirring. Next, under stirring, 416.8 g (that is, 4.63 mol) of an 80% by mass aqueous acrylic acid solution (hereinafter referred to as “80% AA”) in a polymerization reaction system in a boiling point reflux state for 180 minutes, (Hereinafter referred to as “15% NaPS”) 23.2 g for 195 minutes, 45% by weight sodium hypophosphite aqueous solution (hereinafter referred to as “45% SHP”) 6.4 g for 18 minutes, and then 30.3 g for 192 119.1 g of pure water was dropped from the tip nozzle through separate supply channels for 88 minutes after 92 minutes from the start of polymerization at a feed rate of 2 minutes for 2 minutes. The dropping of each component was continuously performed at a constant dropping rate except for 45% SHP. After the completion of the 80% AA dropwise addition, the reaction solution was maintained at the boiling point reflux state (aged) for another 30 minutes to complete the polymerization. The aqueous solution had a solid content of 46.3% and a weight average molecular weight (Mw) of 8,200.

<Example 1>
17.47 g of the polymer aqueous solution obtained in Production Example 1, 0.68 g of 45% SHP, 1.61 g of 1,3-propanediol (that is, 1,3-propanediol is 20 mol% with respect to the carboxyl group in the polymer) Then, 0.24 g of pure water was sufficiently stirred to obtain the binder 1 of the present invention having a solid content of 50%. The SHP content of the binder 1 was 4.0% by mass with respect to 100% by mass of the polymer. It was 12.1 MPa when the mechanical strength of the test piece created by the above-mentioned method was evaluated.

<Example 2>
18.00 g of the aqueous polymer solution obtained in Production Example 1, 0.64 g of 45% SHP, and 0.98 g of 1,4-butanediol (that is, 1,4-butanediol is 10 mol% with respect to the carboxyl group in the polymer). Then, 0.38 g of pure water was sufficiently stirred to obtain the binder 2 of the present invention having a solid content of 48%. The SHP content of the binder 2 was 4.0% by mass with respect to 100% by mass of the polymer. It was 12.8 Mpa when the mechanical strength of the test piece created by the above-mentioned method was evaluated.

<Example 3>
16.94 g of the polymer aqueous solution obtained in Production Example 1, 0.69 g of 45% SHP, and 1.85 g of 1,4-butanediol (that is, 1,4-butanediol is 20 mol% with respect to the carboxyl group in the polymer). Then, 0.52 g of pure water was thoroughly stirred to obtain the binder 3 of the present invention having a solid content of 50%. The SHP content of the binder 3 was 4.0% by mass with respect to 100% by mass of the polymer. It was 13.2 Mpa when the mechanical strength of the test piece created by the above-mentioned method was evaluated.

<Example 4>
14.81 g of the polymer aqueous solution obtained in Production Example 1, 0.71 g of 45% SHP, 2.83 g of 1,4-butanediol (that is, 1,4-butanediol is 35 mol% with respect to the carboxyl group in the polymer) Then, 1.66 g of pure water was thoroughly stirred to obtain the binder 4 of the present invention having a solid content of 50%. The SHP content of the binder 4 was 4.0% by mass with respect to 100% by mass of the polymer. The mechanical strength of the test piece prepared by the above method was evaluated and found to be 11.2 MPa.

<Comparative Example 1>
17.66 g of the polymer aqueous solution obtained in Production Example 1, 0.66 g of 45% SHP, 1.33 g of ethylene glycol (that is, ethylene glycol is 20 mol% with respect to the carboxyl group in the polymer), and 0.35 g of pure water Stirring gave comparative binder 1 of the invention with a solids content of 49%. The SHP content of Comparative Binder 1 was 4.0% by mass with respect to 100% by mass of the polymer. It was 10.2 MPa when the mechanical strength of the test piece created by the above-mentioned method was evaluated.

<Comparative example 2>
13.15 g of the aqueous polymer solution obtained in Production Example 1, 0.72 g of 45% SHP, 3.59 g of 1,4-butanediol (that is, 1,4-butanediol is 50 mol% with respect to the carboxyl group in the polymer) Then, 2.54 g of pure water was sufficiently stirred to obtain a comparative binder 2 of the present invention having a solid content of 50%. The SHP content of Comparative Binder 2 was 4.0% by mass with respect to 100% by mass of the polymer. It was 6.6 MPa when the mechanical strength of the test piece prepared by the above-mentioned method was evaluated.

  Table 1 summarizes the evaluation results of the test pieces.

  From the results shown in Table 1, it is clear that the cured product of glass beads treated with the binder of the present invention has better strength than the cured product of glass beads treated with the conventional binder. It was.

Claims (1)

A binder comprising (i) a polyacrylic acid polymer, (ii) a nonionic polyhydric alcohol, and (iii) a phosphorus-containing compound as a curing accelerator , wherein the nonionic polyhydric alcohol is: The compound having 3 or more carbon atoms and the nonionic polyhydric alcohol content is 7 mol% or more and 40 mol% or less with respect to 100 mol% of the carboxyl group contained in the polyacrylic acid polymer. Oh it is,
The binder, wherein the nonionic polyhydric alcohol contains at least one selected from the group consisting of propanediol, butanediol, and pentanediol .