WO2021125122A1

WO2021125122A1 - Aqueous polyamide dispersion

Info

Publication number: WO2021125122A1
Application number: PCT/JP2020/046467
Authority: WO
Inventors: 俊成水橋; 純一水川
Original assignee: 住友精化株式会社
Priority date: 2019-12-18
Filing date: 2020-12-14
Publication date: 2021-06-24
Also published as: JPWO2021125122A1

Abstract

Provided is an aqueous polyamide dispersion that suppresses occurrence of polyamide agglomerates even in regions having a neutral pH (approximately 7, for example). More specifically, provided is an aqueous polyamide dispersion containing an aqueous medium, a polyamide dispersed in the aqueous medium, and a polyalkylene polyamine alkylene oxide adduct having a melting point of 25°C or higher.

Description

Polyamide aqueous dispersion

This disclosure relates to an aqueous polyamide dispersion and the like.

Since the aqueous dispersion of polyamide can impart solvent resistance, chemical resistance, abrasion resistance, gas barrier property, adhesiveness, etc. by forming a polyamide coating coating on the base material. , Water-based inks, paper treatment agents, binders, lubricants, steel plate surface treatment agents, surface modifiers, hot melt adhesives such as interlining adhesives, etc. are widely used.

In particular, the aqueous dispersion of polyamide is used for the purpose of improving the adhesion with the matrix resin in the composite material in which the thermoplastic resin such as the polyamide resin is used as the matrix resin.

Japanese Unexamined Patent Publication No. 2014-105402 JP-A-2017-114942 International Publication No. 2014/136888

The conventional polyamide aqueous dispersion is an anionic (for example, about pH 9 to 10) aqueous dispersion, and when the pH of the aqueous dispersion becomes low, for example, by adding an acidic substance, polyamide aggregates are formed. Therefore, the usable pH range has been limited.

The present inventors can suppress the formation of polyamide agglomerates even in the neutral pH range if the aqueous polyamide dispersion contains a specific polyalkylene polyamine alkylene oxide adduct in addition to the polyamide. We found the sex and made further improvements. The findings obtained are disclosed herein.

The present disclosure includes, for example, the subjects described in the following sections.
Item 1.
A polyamide aqueous dispersion containing an aqueous medium, a polyamide dispersed in the aqueous medium, and a polyalkylene polyamine alkylene oxide adduct having a melting point of 25 ° C. or higher.
Item 2.
Polyamides are 6-nylon, 66-nylon, 610-nylon, 11-nylon, 12-nylon, 6/66 copolymerized nylon, 6/610 copolymerized nylon, 6/11 copolymerized nylon, 6/12 copolymerized nylon. , 6/66/11 copolymerized nylon, 6/66/12 copolymerized nylon, 6/66/11/12 copolymerized nylon, 6/66/610/11/12 copolymerized nylon, dimer acid-based polyamide, nylon-based Item 2. The aqueous polyamide dispersion liquid according to Item 1, which is at least one selected from the group consisting of elastomers.
Item 3.
Item 2. The polyamide according to Item 1 or 2, wherein the polyalkylene polyamine alkylene oxide adduct is a polyalkylene polyamine alkylene oxide adduct having a number average molecular weight of 5000 to 25000 and a solubility in water at 25 ° C. of 25% by mass or more. Aqueous dispersion.
Item 4.
Item 2. The aqueous polyamide dispersion liquid according to any one of Items 1 to 3, wherein 1 to 20 parts by mass of the polyalkylene polyamine alkylene oxide adduct is contained with respect to 100 parts by mass of the polyamide.
Item 5.
Item 2. The aqueous polyamide dispersion according to any one of Items 1 to 4, wherein the polyalkylene polyamine alkylene oxide adduct is a polyalkylene polyamine alkylene oxide adduct having a structure in which alkylene oxide is addition-polymerized to polyethyleneimine.
Item 6.
Item 2. The aqueous polyamide dispersion liquid according to any one of Items 1 to 5, wherein the volume average particle size of the polyamide is 1 μm or less.
Item 7.
Item 2. The aqueous polyamide dispersion according to any one of Items 1 to 6, wherein the amount of polyamide having a particle size of 2 μm or more is 15% by volume or less of the total amount of polyamide when the pH is lowered to 6.5.
Item 8.
A coating agent containing the polyamide aqueous dispersion according to any one of Items 1 to 7.
Item 9.
A molded body processed by using the coating agent according to Item 8.

Provided is a polyamide aqueous dispersion in which the formation of polyamide agglutinating is suppressed even in a region where the pH is neutral (for example, about 7).

The present disclosure preferably includes, but is not limited to, a polyamide aqueous dispersion containing a specific polyalkylene polyamine alkylene oxide adduct, a coating agent containing the polyamide aqueous dispersion, and the like. Includes everything disclosed herein and recognizable to those skilled in the art.

The polyamide aqueous dispersion included in the present disclosure includes an aqueous medium, a polyamide dispersed in the aqueous medium, and a polyalkylene polyamine alkylene oxide adduct. The polyamide aqueous dispersion may be referred to as "the polyamide aqueous dispersion of the present disclosure".

Water is preferable as the aqueous medium, and various types of water such as tap water, industrial water, ion-exchanged water, deionized water, and pure water can be used. Deionized water and pure water are particularly preferable. Further, as the aqueous medium, a pH adjuster, a viscosity regulator, a fungicide and the like may be appropriately added to water, if necessary.

As the polyamide, a known one or one manufactured by a known method can be used. Commercially available products may be used.

More specifically, examples thereof include polyamides produced by a method such as polycondensation of diamine and dicarboxylic acid, polycondensation of ω-amino-ω'carboxylic acid, or ring-opening polymerization of cyclic lactam. That is, examples thereof include polyamides in which diamine and dicarboxylic acid are polycondensed, polyamides in which ω-amino-ω'carboxylic acid is polycondensed, and polyamides in which cyclic lactam is ring-opened polymerized. At the time of polycondensation or ring-opening polymerization here, a dicarboxylic acid or a monocarboxylic acid can be used as a polymerization regulator.

The polyamide in which diamine and dicarboxylic acid are polycondensed is, in other words, a polyamide having diamine and dicarboxylic acid as a monomer structural unit, and the polyamide in which ω-amino-ω'carboxylic acid is polycondensed is, in other words, ω. A polyamide having -amino-ω'carboxylic acid as a monomer structural unit, and a polyamide in which cyclic lactam is ring-open polymerized is, in other words, a polyamide having cyclic lactam as a monomer structural unit.

Examples of the diamine include ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, and 1,10-diaminodecane. , Phenylenediamine, metaxylylenediamine and the like.

Examples of dicarboxylic acids include glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, nonandicarboxylic acid, decandicarboxylic acid, tetradecanedicarboxylic acid, octadecanedicarboxylic acid, fumaric acid, phthalic acid, and xylylene dicarboxylic acid. Examples thereof include acids and dimeric acids (unsaturated dicarboxylic acids having 36 carbon atoms synthesized from unsaturated fatty acids containing linoleic acid and oleic acid as main components).

Examples of the ω-amino-ω'carboxylic acid include 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and the like.

Examples of the annular lactam include ε-caprolactam, ω-enantractum and ω-lauryl lactam.

The dicarboxylic acid used as the polymerization regulator is the same as the dicarboxylic acid used in the production of the polyamide, for example, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, nonandicarboxylic acid. , Decandicarboxylic acid, tetradecanedicarboxylic acid, octadecanedicarboxylic acid, fumaric acid, phthalic acid, pimelic acid, dimeric acid and the like. Examples of the monocarboxylic acid include caproic acid, heptanic acid, nonanoic acid, undecanoic acid, dodecanoic acid and the like.

In the present invention, among the polyamides,-[NH (CH ₂ ) ₅ CO]-,-[NH (CH ₂ ) ₆ NHCO (CH ₂ ) ₄ CO]-,-[NH (CH ₂ ) ₆ NHCO (CH ₂ ) ₈ CO]-,-[NH (CH ₂ ) ₁₀ CO]-,-[NH (CH ₂ ) ₁₁ CO]-, _{and-[NH (CH 2} ) ₂ NHCO-D-CO]-( In the formula, D represents an unsaturated hydrocarbon having 34 carbon atoms), and a polyamide having at least one or two or more selected from the group consisting of structural units is preferably used.

Examples of such polyamides include nylon, specifically 6-nylon, 66-nylon, 610-nylon, 11-nylon, 12-nylon, 6/66 copolymerized nylon, 6/610 copolymerized nylon. , 6/11 Copolymerized Nylon, 6/12 Copolymerized Nylon, 6/66/11 Copolymerized Nylon, 6/66/12 Copolymerized Nylon, 6/66/11/12 Copolymerized Nylon, or 6/66/610 / 11/12 Copolymerized nylon and the like are exemplified. In addition, "/" here is a symbol used to indicate that it is a copolymer of each nylon. For example, 6/66 copolymerized nylon represents a copolymerized nylon of 6-nylon and 66-nylon.

Further, as an example of the polyamide that can be used, a dimer acid-based polyamide and a polyamide elastomer are also exemplified. Specific examples of the polyamide elastomer include a polyamide elastomer which is a copolymer of nylon and polyester or a copolymer of nylon and polyalkylene ether glycol. Examples of the polyalkylene ether glycol include polyethylene oxide glycol, polypropylene oxide glycol, polytetramethylene oxide glycol, polyhexamethylene oxide glycol and the like. Examples of the polyester include polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polytrimethylene naphthalate, and polybutylene naphthalate.

Polyamide can be used alone or in combination of two or more. The polyamide elastomer is not particularly limited, but a block copolymer containing a polyamide block and a polyether block is preferable. In particular, a block copolymer having a structure in which a polyamide and a polyether are copolymerized is preferable, and a block copolymer having a structure in which a polyamide and a polyether are copolymerized is particularly preferable. Examples of the constituent components of the polyether block include glycol compounds such as polyethylene oxide glycol, polypropylene oxide glycol, polytetramethylene oxide glycol and polyhexamethylene oxide glycol, and diamine compounds such as polyether diamine. Two or more kinds of these constituents may be used. As such a polyamide elastomer, several types having different molecular structures of the bonding portion between the polyamide block and the polyether block, that is, the bonding morphology, for example, "(polyamide block) -CO-NH- (polyamide block)" Examples thereof include a polyether block amide copolymer having a bonded form, a polyether ester block amide copolymer having a bonded form of "(polyamide block) -CO-O- (polyamide block)", and the like.

As the polyalkylene polyamine alkylene oxide adduct, for example, one having a structure in which an alkylene oxide is added to 1 to 3 active hydrogens in an amino compound is preferable. Specifically, for example, those having a structure in which alkylene oxide is addition-polymerized with amines such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine and polyethyleneimine are preferable, and ethylene oxide / propylene oxide is particularly preferable. Is more preferably blocked or randomly subjected to addition polymerization. The polyethyleneimine may be either linear or branched.

The polyalkylene polyamine alkylene oxide adduct is not particularly limited, but a polyethyleneimine alkylene oxide adduct having a structure in which polypropylene oxide and polyethylene oxide are added as alkylene oxide components to polyethyleneimine in a block is particularly preferably used. ..

As a polyethyleneimine alkylene oxide adduct, the following formula (1):

(In the formula, AO represents an alkylene oxide and n represents an integer), and those containing a repeating unit represented by the above are also preferably mentioned. As the AO (alkylene oxide) here, for example, -CH ₂ CH ₂ O-, -CH ₂ CH (CH ₃ ) O-, or a block or a random copolymer thereof is preferably mentioned.

The polyalkylene polyamine alkylene oxide adduct used in the aqueous polyamide dispersion of the present disclosure has a melting point of 25 ° C. or higher, preferably 25 to 100 ° C. The upper or lower limit of the range is, for example, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, It may be 97, 98, or 99 ° C. The range is, for example, more preferably 30 to 80 ° C, still more preferably 60 to 80 ° C.

The number average molecular weight of the polyalkylene polyamine alkylene oxide adduct is preferably 5000 to 25000. The upper or lower limit of the range is, for example, 6000, 7000, 8000, 9000, 10000, 11000, 12000, 13000, 14000, 15000, 16000, 17000, 18000, 19000, 20000, 21000, 22000, 23000, or 24000. May be good. The range is, for example, more preferably 10,000 to 20,000. When the number average molecular weight is 5000 or more, it works more preferably as a protective colloid around the particles as a polymer-type nonionic surfactant, and can preferably contribute to the stabilization of the aqueous dispersion. Further, when the number average molecular weight is 25,000 or less, not only contributes to the stabilization of the particles, but also the viscosity of the aqueous dispersion does not become too high, which can be a more practical and preferable viscosity.

The value of the number average molecular weight here is a value obtained by the measurement method described below. Number average molecular weight measurement method: A tetrahydrofuran solution containing a polyalkylene polyamine alkylene oxide adduct at a concentration of 0.2% by mass is prepared, and measurement is performed using a high performance liquid chromatograph. Then, a molecular weight marker (polystyrene) having a known molecular weight is measured under the same conditions, a calibration curve is created, and the number average molecular weight (Mn) is calculated. The measurement conditions are as follows.

Measuring machine: GPC-101 (Shodex)
Column: TSK GEL Multipore HZ-N manufactured by Tosoh Corporation
Column temperature: 40 ° C
Outflow: tetrahydrofuran Flow rate: 0.25 ml / min

The solubility of the polyalkylene polyamine alkylene oxide adduct in water is preferably 25% by mass or more, more preferably 26, 27, 28, or 29% by mass or more, and further preferably 30% by mass or more. Is. The solubility in water here is a value obtained as follows when examined using water at 25 ° C.

Solubility (% by mass) = A / (A + B) x 100
However, A: mass of polyalkylene polyamine alkylene oxide adduct B: mass of water in which the polyalkylene polyamine alkylene oxide adduct is dissolved.

Such a polyalkylene polyamine alkylene oxide adduct is commercially available as a polymer type nonionic surfactant, and for example, "Discol N" which is a polyalkylene polyamine alkylene oxide adduct manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. -518 ”can be used.

The polyalkylene polyamine alkylene oxide adduct can be used alone or in combination of two or more.

The amount of the polyalkylene polyamine alkylene oxide adduct used in the aqueous polyamide dispersion of the present disclosure is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the polyamide. The upper or lower limit of the range may be, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, or 19 parts by mass. Good. The range is, for example, more preferably 3 to 17 parts by mass, still more preferably 5 to 15 parts by mass.

The aqueous polyamide dispersion containing no polyalkylene polyamine alkylene oxide adduct is usually anionic (for example, pH 9 to 10). When an acidic substance is added to the polyamide aqueous dispersion, polyamide agglomerates are likely to be formed, whereas the polyamide aqueous dispersion also containing a polyalkylene polyamine alkylene oxide adduct has a neutral region (for example, about pH 7 or more acidic). It can maintain a stable state up to pH). Therefore, not only the range of use of the aqueous polyamide dispersion can be expanded, but also it can be mixed with an acidic additive or the like, and various performance improvements and the like can be easily performed.

Although we do not want a theoretical limitation, the reason why the stable state can be maintained up to the neutral region by adding the polyalkylene polyamine alkylene oxide adduct to the aqueous polyamide dispersion is that it is a general polymer type non-ion. When using a sex surfactant, these polymer chains are only freely present around the particles and have a weak chemical stabilizing effect, whereas a polyalkylene polyamine alkylene oxide adduct having a nitrogen atom is used. In this case, nitrogen atoms are attracted to the carbonyl group on the surface of the polyamide particles, and the polyalkylene polyamine alkylene oxide adduct is present relatively close to the particle surface, which contributes to a greater stabilizing effect. Guess.

The method for producing the aqueous polyamide dispersion liquid of the present disclosure is not particularly limited. For example, it can be produced by a method including a step of mixing an aqueous dispersion in which polyamide is dispersed (hereinafter, also referred to as a polyamide aqueous dispersion precursor) and a polyalkylene polyamine alkylene oxide adduct. It can also be produced by a method including a step of dispersing polyamide using an aqueous solution of a polyalkylene polyamine alkylene oxide adduct to obtain an aqueous dispersion.

The method for producing the polyamide aqueous dispersion precursor is not particularly limited, and any method may be used as long as the polyamide can be uniformly dispersed in the aqueous medium.

For example, a method of dispersing polyamide powder obtained by pulverizing polyamide by a pulverization method such as a mechanical pulverization method, a freezing pulverization method, or a wet pulverization method in an aqueous medium, or emulsifying using polyamide and a basic substance. Examples thereof include a method of producing an aqueous dispersion, a method of emulsifying polyamide using a surfactant, and producing an aqueous dispersion.

Below, as a typical production example, a method of emulsifying using polyamide and a basic substance to produce an aqueous dispersion is shown.

In this production method, for example, a polyamide, a basic substance, and an aqueous medium are put into a container to prepare a mixed solution thereof.

The container used for preparing the mixture is a pressure-resistant container provided with a heating means for heating the polyamide to a temperature higher than the temperature at which it softens in an aqueous medium and a stirring means capable of applying a shearing force to the contents. Is preferable. For example, a pressure resistant autoclave with a stirrer is preferable.

Next, the polyamide, basic substance and aqueous medium are mixed in this container to obtain a mixed solution. Then, the mixed solution is heated to a temperature equal to or higher than the softening temperature of the polyamide and stirred to emulsify the mixture to obtain an emulsion. Cooling the emulsion to room temperature gives a polyamide aqueous dispersion precursor.

The basic substance is not particularly limited, and examples thereof include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, ammonia, and amine compounds. The basic substance may be used alone or in combination of two or more. Of these, sodium hydroxide and / or potassium hydroxide are particularly preferably used from the viewpoint of excellent static stability of the dispersion.

The amount of the basic substance used is 0.1 to 2 mol per 1 mol of the terminal carboxyl group of the polyamide from the viewpoint of excellent static stability such as little change in the viscosity of the obtained aqueous dispersion with time. It is preferably 0.4 to 1 mol, more preferably 0.4 to 1 mol.

The amount of the polyamide used is not particularly limited, but is preferably set to 0.1 to 80 parts by mass, and set to 20 to 60 parts by mass with respect to 100 parts by mass of the obtained polyamide aqueous dispersion precursor. It is more preferable to do so.

Further, as long as the effect of the present invention is not impaired, a polyamide aqueous dispersion precursor can be obtained by using a basic substance and a surfactant (dispersion stabilizer) in combination.

As a surfactant (dispersion stabilizer) used to obtain a polyamide aqueous dispersion precursor (that is, to disperse polyamide in an aqueous medium), the effect of the obtained polyamide aqueous dispersion of the present disclosure can be used. Additives such as anionic surfactants, nonionic surfactants, and polymer-based dispersants can also be used as long as they are not impaired.

Examples of the anionic surfactant include aliphatic polyoxyalkylene alkyl ether sulfates, polyoxyalkylene alkylphenyl ether sulfates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyldiphenyl sulfonates, and α-olefins. Examples thereof include sulfonates, alkyl sulfates, naphthalene sulfonate formalin condensates, dialkyl sulfosuccinates, polyoxyethylene alkyl ether acetates, rosin salts and fatty acid salts.

Examples of the nonionic surfactant include polyethylene glycol, ethylene oxide / propylene oxide copolymer, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl thioether, polyoxyethylene sorbitan fatty acid monoester, and polyoxy. Examples thereof include ethylene alkyl amide and polyglycerin ester.

Examples of the polymer-based dispersion stabilizer include polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, hydroxypropyl cellulose, polyvinylpyrrolidone, polyacrylic acid salt, polyacrylic acid ester salt, alginate, and salts of ethylene / acrylic acid copolymers. (Especially ammonium salt), styrene / maleic anhydride copolymer salt, styrene-maleic acid monoester copolymer salt, isobutylene / maleic anhydride copolymer salt, carboxymethyl cellulose salt and the like can be mentioned.

Among these additives, a nonionic surfactant and a polymer-based dispersion stabilizer are preferably used from the viewpoint of enhancing the stability of the obtained aqueous dispersion liquid of the present disclosure. Above all, the obtained aqueous dispersion of the present disclosure has excellent heat resistance, is not easily decomposed even when processed at a high temperature for a long time, and has good adhesion between the laminate treated with the aqueous dispersion and the matrix resin. Ethylene oxide / propylene oxide copolymer, polyoxyethylene alkyl ether (eg polyoxyethylene lauryl ether, polyoxyethylene tridecyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene mi Listel ether, polyoxyethylene octyldodecyl ether, etc.), ethylene / acrylic acid copolymer ammonium salt, styrene / maleic anhydride copolymer ammonium salt, styrene-maleic acid monoester copolymer ammonium salt, isobutylene / maleic acid The ammonium salt of the ester copolymer is preferably used.

These additives can be used alone or in combination of two or more.

The amount of the additive used is preferably less than 10 parts by mass, more preferably 0.1 to 8 parts by mass with respect to 100 parts by mass of the polyamide. However, since the use of these additives may adversely affect the adhesiveness between the laminate treated with the obtained dispersion and the matrix resin, refer to the above amount and avoid using a relatively large amount. It is desirable to set it appropriately.

Note that these additives may be further added after the polyamide aqueous dispersion precursor is obtained in the manufacturing process.

The polyamide aqueous dispersion of the present disclosure can be obtained by mixing the polyalkylene polyamine alkylene oxide adduct with the polyamide aqueous dispersion precursor prepared as described above. The method for mixing the polyamide aqueous dispersion precursor and the polyalkylene polyamine alkylene oxide adduct is not particularly limited. For example, the polyamide aqueous dispersion precursor and the polyalkylene polyamine alkylene oxide adduct are put into the same container and stirred. Then, a method of mixing and the like can be mentioned.

The concentration (w / w%) of the polyamide in the aqueous polyamide dispersion of the present disclosure is preferably 0.1 to 80% by mass, more preferably 1 to 60% by mass, and further preferably 5 to 50% by mass. It is mass%. When the concentration of polyamide is 80% by mass or less, the stability of the aqueous polyamide dispersion can be further improved. Further, when the concentration is 0.1% by mass or more, the polyamide can be more easily adhered to the adherend of the laminated body.

In the aqueous polyamide dispersion of the present disclosure, the average particle size of the dispersed polyamide (particles) is, for example, preferably less than 2 μm. The lower limit of the average particle size is not particularly limited, but is, for example, 0.05 μm or more. For example, it is more preferably less than 2 μm and 0.05 μm or more. The upper or lower limit of the range is, for example, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0. It may be 9.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1 μm. Further, as described above, the lower limit does not have to be set. For example, it can be more preferably 1.5 μm or less, 1.0 μm or less, or 0.8 μm or less. In the present specification, the average particle size of the polyamide is the volume average particle size measured by the laser diffraction type particle size distribution measurement method. That is, it is a volume average particle diameter value obtained when the polyamide aqueous dispersion is measured by a laser diffraction type particle size distribution measuring device.

Further, the aqueous polyamide dispersion liquid of the present disclosure is preferably one in which agglomerates of polyamide are unlikely to be formed when the pH is lowered by using an acidic substance. The degree of aggregation of polyamide can be indicated by, for example, the ratio (volume%) of the total polyamide amount (volume) to the polyamide amount (volume) having a particle size of 2 μm or more. The value is obtained by measuring the particle size distribution by the laser diffraction / scattering method. For example, when the pH is lowered to 6.5, the amount of polyamide having a particle size of 2 μm or more is preferably 15% by volume or less of the total amount of polyamide, and is 14, 13, 12, 11, or 10% by volume or less. Is more preferable, and 9, 8, 7, 6, 5, 4, or 3% by volume or less is further preferable. Further, for example, when the pH is lowered to 6.4, the amount of polyamide having a particle size of 2 μm or more is preferably 15% by volume or less of the total amount of polyamide, and is 14, 13, 12, 11, or 10% by volume. It is more preferably 9, 8, 7, 6, 5, 4, or 3% by volume or less. Further, for example, when the pH is lowered to 6.2, the amount of polyamide having a particle size of 2 μm or more is preferably 15% by volume or less of the total amount of polyamide, and is 14, 13, 12, 11, or 10% by volume. It is more preferably 9, 8, 7, 6, 5, 4, or 3% by volume or less.

As the acidic substance used to lower the pH of the aqueous polyamide dispersion, an acidic substance that does not affect the aggregation of the polyamide is preferable, and more specifically, for example, ammonium sulfate and the like are preferably mentioned.

The aqueous polyamide dispersion liquid of the present disclosure preferably includes, for example, one having a pH of less than 6.7 and an average particle size of polyamide satisfying the above preferable range. The pH range is 6.65 or less, 6.6 or less, 6.55 or less, 6.5 or less, 6.45 or less, 6.4 or less, 6.35 or less, 6.3 or less, 6.25 or less, It may be 6.2 or less, 6.15 or less, or 6.1 or less. Further, as long as the average particle size of the polyamide satisfies the above preferable range, the lower limit of pH is not particularly limited. For example, 5, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, or 6.

Further, the aqueous polyamide dispersion liquid of the present disclosure preferably includes, for example, one having a pH of less than 6.7 and containing no polyamide particles having an average particle diameter of 2 μm or more. The pH range is 6.65 or less, 6.6 or less, 6.55 or less, 6.5 or less, 6.45 or less, 6.4 or less, 6.35 or less, 6.3 or less, 6.25 or less, It may be 6.2 or less, 6.15 or less, or 6.1 or less. Further, the lower limit of pH is not particularly limited as long as it does not contain polyamide particles having an average particle diameter of 2 μm or more. For example, 5, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, or 6.

In the present specification, the pH of the aqueous polyamide dispersion is a value measured at 25 ° C. using a pH meter.

Various molded products can be processed by using the coating agent containing the aqueous polyamide dispersion liquid of the present disclosure. The coating agent is useful as a material for producing various molded products.

The method for producing the molded product is not particularly limited, but the step of applying the aqueous polyamide dispersion liquid of the present disclosure to the base material or pouring it into a mold, and drying the aqueous dispersion of the coated or poured polyamide aqueous dispersion. It involves a step (ie, removing water). By a method for producing a molded product including such a step, it is possible to obtain a molded product having various forms such as a film, a film or a sheet containing an aqueous polyamide dispersion.

The method for applying the aqueous polyamide dispersion liquid of the present disclosure to the substrate is not particularly limited, and for example, a coating method using a brush, a spatula, a roller, a caulking gun, a silk screen, an air spray, a nozzle spray, a roll coater, or the like. Can be mentioned.

The amount of the polyamide aqueous dispersion applied to the base material is appropriately set according to the purpose, and for example, the film is applied so that the thickness of the film obtained from the polyamide aqueous dispersion of the present disclosure is 0.001 mm to 5 mm.

The method of pouring the aqueous polyamide dispersion into the mold is not particularly limited.

For example, a method of applying a polyamide aqueous dispersion to a substrate or pouring it into a mold and then removing water can be mentioned. The drying temperature in the step of removing water is not particularly limited, but is usually set to 40 to 300 ° C.

The drying time is not particularly limited, and for example, when drying at 100 ° C., it is 0.2 to 2 hours.

The base material used for manufacturing the molded product is not particularly limited, but is, for example, metal such as aluminum or copper, glass, wood, rubber, thermoplastic resin, thermosetting resin, and further reinforced with reinforcing fibers or fillers. Manufactured from resin or the like. The thickness and shape of the base material are not particularly limited.

The coating side of the aqueous polyamide dispersion in the molded product thus obtained (for example, a laminate obtained by coating on a base material and drying) and a further base material are combined, for example, hot pressing. A composite material in which base materials are bonded in layers can be produced by pressurizing the mixture at 120 to 300 ° C., if necessary, to 0.1 to 100 MPa and heating for 1 to 500 seconds. The base material to be bonded may be a different type of base material or the same type of base material.

The polyamide aqueous dispersion of the present disclosure includes materials for manufacturing automobile parts, sports-related products, medical instruments, etc., coating agents for paper and films, adhesives, surface modifiers, raw materials for foam rubber, coating agents, etc. Alternatively, in a wide range of applications such as manufacturing materials such as hoses, tubes, belts, gaskets and packings, sealants for connectors and sensors, thermal adhesives, cord coatings, materials for manufacturing electrical and electronic parts such as antenna covers, etc. It can be utilized.

The aqueous polyamide dispersion liquid of the present disclosure can form a film having excellent adhesiveness to the matrix resin on the substrate. Among the matrix resins, a polyamide resin is preferable, and a good composite material can be obtained.

In this specification, "including" also includes "consisting of" and "consisting of" (The term "comprising" includes "consisting essentially of" and "consisting of.").

Further, the various characteristics (property, structure, function, etc.) described for each of the above-described embodiments may be combined in any way in specifying the subject matter included in the present disclosure.

Hereinafter, the subject matter included in the present disclosure will be described in more detail, but the subject matter is not limited to the following examples.

Production of aqueous polyamide aqueous dispersion
Example 1
240 g of 6/66/12 copolymerized nylon (melting point 120 ° C.), 150 g of deionized water and 10 g of 10% sodium hydroxide aqueous solution as polyamide in a pressure resistant autoclave having an internal volume of 1 liter equipped with a turbine-type stirring blade having a diameter of 50 mm. It was prepared and sealed. Next, the stirrer was started, and the temperature inside the autoclave was raised to 160 ° C. while stirring at a rotation speed of 500 rpm. After stirring for another 30 minutes while maintaining the internal temperature at 160 ° C., the mixture was cooled, and 24.5 g of an aqueous dispersion (solid content concentration 29% by weight) of an ammonium salt of an ethylene-acrylic acid copolymer and 198 g of deionized water were added. .. Further, after cooling to room temperature, 120 g of "Discol N-518", which is an aqueous solution of a polyalkylene polyamine alkylene oxide adduct manufactured by Daiichi Kogyo Seiyaku Co., Ltd. (number average molecular weight: 16000, melting point 64.5 ° C., in water). Solubility was 30% by mass or more and less than 35% by mass, solid content concentration: 20% by mass) and 33.5 g of deionized water were added and mixed well to obtain a polyamide aqueous dispersion.

The solubility of the polyalkylene polyamine alkylene oxide adduct (Discol N-518) in water was determined by drying Discol N-518, adding a predetermined amount to water, stirring at 25 ° C. for 5 hours, and then stirring the mixture. It was examined whether it would dissolve and calculated by the following formula.

At 30% by mass, the solution was fluid, while at 35% by mass, a gel-like substance was formed and there was undissolved residue. Therefore, the solubility in water was judged to be 30% by mass or more and less than 35% by mass. ..

Further, the volume average particle size of the polyamide in the polyamide aqueous dispersion was measured using a diffraction type particle size distribution measuring device (Shimadzu Corporation, trade name "SALD-2300") and found to be 0.53 μm.

Example 2
An aqueous polyamide dispersion was obtained in the same manner as in Example 1 except that the amount of "Discol N-518" used was 90 g and the amount of deionized water used was 47.8 g.

The volume average particle size of polyamide in this aqueous dispersion was measured using a diffraction type particle size distribution measuring device (Shimadzu Corporation, trade name "SALD-2300") and found to be 0.53 μm.

Comparative Example 1
A polyamide dispersion was obtained in the same manner as in Example 1 except that 53 g of deionized water was added instead of 120 g of "Discol N-518" (solid content concentration: 20% by mass).

Comparative Example 2
Instead of 120 g of "Discol N-518" (solid content concentration: 20% by mass), 24 g (number average molecular weight) of "Discol N-206" which is a polyalkylene polyamine alkylene oxide adduct manufactured by Daiichi Kogyo Seiyaku Co., Ltd. 33,000, melting point less than 25 ° C, solubility in water 20% by mass or more and less than 25% by mass), and the amount of deionized water used was 96 g. Got

The solubility of Discol N-206 in water is a value examined in the same manner as the method for examining the solubility of Discol N-518 in water.

Comparative Example 3
In Example 1, 24 g of an ethylene oxide / propylene oxide copolymer (Pluronic F108 ADEKA Corporation) was used as a nonionic surfactant instead of 120 g of "Discol N-518" (solid content concentration: 20% by mass). A polyamide dispersion was obtained in the same manner as in Example 1 except that the amount of deionized water used was 96 g.

According to the catalog of Dai-ichi Kogyo Seiyaku Co., Ltd., both "Discol N-518" and "Discol N-206" used as the polyalkylene polyamine alkylene oxide adduct in the above example have the following formulas ( 1):

(In the formula, AO represents an alkylene oxide and n represents an integer.) It is described as a polyalkylene polyamine alkylene oxide adduct consisting of repeating units represented by.

Evaluation of Stability of Aqueous Polyamide Dispersion The aqueous polyamide dispersions (Examples 1 and 2 and Comparative Examples 1 to 3) obtained as described above were mixed with deionized water to have a polyamide concentration of 1 (w / w)%. 50 ml of the diluted polyamide aqueous dispersion was weighed out, and a 1 mol / L ammonium sulfate aqueous solution was gradually added as an acid component, and the amount of addition at which particle aggregation started was examined. Regarding the agglutination of particles, the agglutination state was confirmed by particle size distribution measurement using a diffraction type particle size distribution measuring device (Shimadzu Corporation, trade name “SALD-2300”).

Even if the pH of the polyamide dispersion was lowered to 6.4, those in which no agglomerates (particles of 2 μm or more) were not formed were evaluated as ◯, and those in which agglomerates were formed by 6.4 were evaluated as ×.

When ammonium sulfate, which is an acidic component, is added to the polyamide dispersion to reduce the pH, agglomerates are formed at a pH of 7.2 in Comparative Example 1 and agglomerates are formed at a pH of 7.2 in Comparative Example 2. In Comparative Example 3, agglomerates were formed at a pH of 6.7, whereas in Example 1, the dispersed state could be maintained up to pH 6.2, that is, the dispersed state was maintained even at a pH of 6.4. It was found that the content of particles of 2 μm or more was 0% by volume, and in Example 2, the dispersed state could be maintained up to pH 6.4, and the content of particles of 2 μm or more was 0% by volume.

Further, in Comparative Example 1, when 3 mmol of ammonium sulfate, which is an acidic component, was added to the polyamide dispersion, aggregates were formed, and in Comparative Example 2, when 3 mmol of ammonium sulfate, which was an acidic component, was added to the polyamide dispersion, aggregates were formed. In Comparative Example 3, when 9 mmol of ammonium sulfate, which is an acidic component, was added to the polyamide dispersion, aggregates were formed at a pH of 6.7, whereas in Example 1, ammonium sulfate, which is an acidic component, was added to the polyamide dispersion up to 50 mmol. It can be seen that the dispersed state can be maintained even if it is added, and in Example 2, the dispersed state can be maintained even if ammonium sulfate, which is an acidic component, is added to the polyamide dispersion liquid up to 30 mmol.

The "content (%) of particles of 2 μm or more" in Table 1 represents the volume% with respect to the total amount of polyamide contained in the dispersion liquid.

From the above results, it was found that the aqueous polyamide dispersion containing the polyalkylene polyamine alkylene oxide adduct can maintain the dispersed state even in a low pH region (a region having a pH of about 7 or lower).

Claims

A polyamide aqueous dispersion containing an aqueous medium, a polyamide dispersed in the aqueous medium, and a polyalkylene polyamine alkylene oxide adduct having a melting point of 25 ° C. or higher.
Polyamides are 6-nylon, 66-nylon, 610-nylon, 11-nylon, 12-nylon, 6/66 copolymerized nylon, 6/610 copolymerized nylon, 6/11 copolymerized nylon, 6/12 copolymerized nylon. , 6/66/11 copolymerized nylon, 6/66/12 copolymerized nylon, 6/66/11/12 copolymerized nylon, 6/66/610/11/12 copolymerized nylon, dimer acid-based polyamide, nylon-based The aqueous polyamide dispersion according to claim 1, which is at least one selected from the group consisting of elastomers.
The polyalkylene polyamine alkylene oxide adduct according to claim 1 or 2, wherein the polyalkylene polyamine alkylene oxide adduct is a polyalkylene polyamine alkylene oxide adduct having a number average molecular weight of 5000 to 25000 and a solubility in water at 25 ° C. of 25% by mass or more. Polyamide aqueous dispersion.
The aqueous polyamide dispersion according to any one of claims 1 to 3, wherein 1 to 20 parts by mass of a polyalkylene polyamine alkylene oxide adduct is contained with respect to 100 parts by mass of the polyamide.
The aqueous polyamide dispersion according to any one of claims 1 to 4, wherein the polyalkylene polyamine alkylene oxide adduct is a polyalkylene polyamine alkylene oxide adduct having a structure in which alkylene oxide is addition-polymerized to polyethyleneimine.
The aqueous polyamide dispersion according to any one of claims 1 to 5, wherein the average particle size of the polyamide is 1.0 μm or less.
The aqueous polyamide dispersion according to any one of claims 1 to 6, wherein the amount of polyamide having a particle size of 2 μm or more is 15% by volume or less of the total amount of polyamide when the pH is lowered to 6.5.
A coating agent containing the polyamide aqueous dispersion according to any one of claims 1 to 7.
A molded body processed by using the coating agent according to claim 8.