WO2019111611A1

WO2019111611A1 - Adhesive composition

Info

Publication number: WO2019111611A1
Application number: PCT/JP2018/040980
Authority: WO
Inventors: 橋本　雅彦; 孝介森谷
Original assignee: 株式会社Moresco
Priority date: 2017-12-08
Filing date: 2018-11-05
Publication date: 2019-06-13
Also published as: CN111448277A; CN111448277B; JPWO2019111611A1; JP6721801B2

Abstract

The purpose of the present invention is to provide an adhesive composition having exceptional color changeability, storage stability, and compatibility. The adhesive composition contains an acrylic block copolymer, a surfactant, a color reagent, and a pH adjuster.

Description

Adhesive composition

The present invention relates to adhesive compositions that indicate wetness.

An adhesive composition containing a coloring reagent or the like that changes color in response to a change in pH is used in disposable nonwoven absorbent articles such as diapers. The adhesive composition is useful as an indicator for notifying the presence of water because it changes color in response to a change in pH when urine or water infiltrates. As the said adhesive composition, the adhesive composition which added the coloring reagent etc. to the water-soluble polymer or the water-insoluble polymer is known.

For example, U.S. Pat. No. 5,958,015 discloses an adhesive composition formulation comprising a water sensitive polymer such as vinyl pyrrolidone / vinyl acetate copolymer.

Patent Document 2 discloses a water-soluble polymer or ethylene vinyl acetate (EVA), styrene-isoprene-styrene (SIS) block copolymer, styrene-butadiene-styrene (SBS) block copolymer, styrene-ethylene-butylene-styrene (SEBS) ) Block copolymers, styrene-ethylene / ethylene-propylene-styrene (SEEPS) block copolymers, high density polyethylene, low density polyethylene, chemically modified polyethylene, amorphous polyalphaolefins (APAO), ethylene / styrene interpolymers (ESI) and A heat melt-type wettability indicator adhesive composition is disclosed that contains a water insoluble polymer such as APAO using a metallocene catalyst.

Japanese Published Patent Publication "JP-A-64-31884" (published February 2, 1989) Japan Published Patent Gazette "Special Table 2012-506915 Gazette" (published on March 22, 2012)

However, adhesive formulations containing the water-sensitive polymer disclosed in Patent Document 1 are considered to have insufficient storage stability because of poor water resistance, heat resistance and oil retention. Therefore, when the diaper using such an adhesive composition is exposed to a high temperature and high humidity environment for a long time during transportation or inventory storage, the exudation of components occurs and the performance as an indicator is impaired. And the design of the diaper may be impaired.

Further, the adhesive composition containing the non-water-soluble polymer disclosed in Patent Document 2 has a low polarity of the non-water-soluble polymer which is the main component, and thus the non-water-soluble polymer and a surfactant imparting hydrophilicity, It is considered that the compatibility with the acidic material (such as fatty acid and rosin acid) for adjusting the pH is poor. Therefore, when the adhesive composition of Patent Document 2 is stored, there is a risk that the active ingredient may leak, and the applied adhesive composition may not be uniform and may not exhibit sufficient performance.

One aspect of the present invention has been made in view of the above-mentioned problems, and its object is to exhibit long-term stability even under high temperature and high humidity environment, and under severe environment associated with import and export. An object of the present invention is to realize an adhesive composition which is resistant to change with time due to a long inventory period and is excellent in quality maintenance.

MEANS TO SOLVE THE PROBLEM In order to solve said subject, this inventor diligently investigates about the component which comprises an adhesive composition, and an adhesive composition is an acryl block copolymer, surfactant, a coloring reagent, and a pH adjuster. It has been found that the above problems can be solved by containing and to complete the present invention. That is, the present invention includes the following configurations.
[1] An adhesive composition for indicating a wetness, which comprises an acrylic block copolymer, a surfactant, a coloring reagent, and a pH adjuster.
[2] The main chain of the acrylic block copolymer is characterized by having a polymer block having a glass transition temperature higher than 40 ° C. and a polymer block having a glass transition temperature lower than 20 ° C. [1] Adhesive composition.
[3] The main chain of the acrylic block copolymer has a structure represented by [A1]-[B]-[A2] or [A]-[B], and the above-mentioned [A1], [A2] and [A] ] Is a polymer block having a glass transition temperature higher than 40 ° C., and the above [B] is a polymer block having a glass transition temperature lower than 20 ° C. [2] object.
[4] The above [A1], [A2] and [A] are polymer blocks derived from methyl methacrylate, and the above [B] is derived from an alkyl (meth) acrylate having 2 to 12 carbon atoms in the alkyl group The adhesive composition according to [3], which is a polymer block.
[5] The proportion of the acrylic block copolymer is 5 to 75% by weight with respect to 100% by weight of the adhesive composition, according to any one of [1] to [4]. Adhesive composition.
[6] The adhesive composition according to any one of [1] to [5], wherein the HLB value of the surfactant is 3 to 20.
[7] The composition according to any one of [1] to [6], wherein the proportion of the surfactant is 3 to 30% by weight with respect to 100% by weight of the adhesive composition. Adhesive composition.
[8] The adhesive composition as described in any one of [1] to [7], wherein the coloring reagent has a color changing region at pH 3 to 8.
[9] The color reagent is selected from the group consisting of methyl red, bromophenol blue, bromocresol green, bromocresol purple, methyl yellow, congo red, methyl orange, litmus, bromothymol blue, cochineal dye and anthocyanin dye The adhesive composition according to any one of [1] to [8], which is at least one kind of
[10] The ratio of the coloring reagent is 0.01% by weight or more based on 100% by weight of the adhesive composition, according to any one of [1] to [9]. Adhesive composition as described. [11] The adhesive composition according to any one of [1] to [10], wherein the pH adjuster is an acidic material.
[12] A water-absorbent article coated at least in part with the adhesive composition according to any one of [1] to [11].

According to one aspect of the present invention, it is possible to provide an adhesive composition which is excellent in color-changeability, storage stability and compatibility.

It is the schematic which shows the structure of the hue change test apparatus of the adhesive composition which concerns on the Example of this invention.

Although one embodiment of the present invention is described below, the present invention is not limited to this. The present invention is not limited to the configurations described below, and various modifications can be made within the scope of the claims, and technical means disclosed in different embodiments and examples can be used. Embodiments and examples obtained by combining as appropriate are also included in the technical scope of the present invention. Also, all the academic and patent documents described in the present specification are incorporated herein by reference.

Further, unless otherwise specified in the present specification, “A to B” representing a numerical range intends “A or more and B or less”. Also, "mass" and "weight" are considered to be synonymous. Moreover, when both "acrylic" and "methacrylic" are meant, it is described as "(meth) acrylic", and when both "acrylate" and "methacrylate" are meant, it is described as "(meth) acrylate."

[1. Adhesive composition]
An adhesive composition according to an embodiment of the present invention is an adhesive composition for indicating wetness, which comprises (a) an acrylic block copolymer, (b) a surfactant, and (c) a color reagent. And (d) a pH adjuster. Thereby, the said adhesive composition is excellent in discoloration property, storage stability, and compatibility. Specifically, by containing the acrylic block copolymer, the adhesive composition is excellent in compatibility with other additives such as a surfactant, a coloring reagent and a pH adjuster, and is separated at the time of melting. It is hard to occur. This is because the polarity of the acrylic block copolymer is high. In addition, the adhesive composition exhibits storage stability by containing the acrylic block copolymer. This is because the acrylic block copolymer can improve the cohesion of the entire adhesive composition so that shape stability can be imparted to the adhesive composition, as well as water resistance, heat resistance and oil retention. It is because it is excellent. By containing the surfactant, the adhesive composition has hydrophilicity and can react to the presence of moisture. The adhesive composition has a discoloring property by containing the coloring reagent. By containing the pH adjuster, in the adhesive composition, the difference in color change before and after the reaction with water becomes larger. In the present specification, "an adhesive composition that indicates the degree of wetness" intends an adhesive composition that changes color in response to the presence of moisture.

The adhesive composition has a viscosity of 150,000 mPa · s or less, more preferably 30,000 mPa · s or less, more preferably 5,000 mPa · s or less at 180 ° C. or less, more preferably 120 ° C. or less, still more preferably 100 ° C. or less. -It is preferable that it is s or less. By the said structure, an adhesive composition can be directly apply | coated to the low heat resistant substance, such as a polyethylene film which is a constituent material of a disposable diaper. That is, the adhesive composition exhibits excellent coatability.

The adhesive composition is preferably in a state where there is no separation of the solution at 180 ° C. and no generation of precipitate and insoluble component (sludge). With this configuration, variations in quality do not occur, and the yield can be increased.

<1-1. Acrylic block copolymer>
As used herein, "acrylic block copolymer" intends a polymer having at least one block structure containing an alkyl (meth) acrylate monomer. That is, the acrylic block copolymer may be an acrylic block copolymer having one block structure, or may be an acrylic block copolymer having a diblock structure, a triblock structure, or four or more multiblock structures. . The acrylic block copolymer may be used alone or in combination of two or more. Hereinafter, the “block structure containing an alkyl (meth) acrylate monomer” is also referred to as a “polymer block derived from an alkyl (meth) acrylate”. The alkyl (meth) acrylate monomer is preferably an alkyl (meth) acrylate monomer in which the alkyl group has 1 to 12 carbon atoms. The acrylic block copolymer may have two or more types of acrylic polymer blocks, and may contain polymer blocks other than acrylic polymer blocks, but is preferably composed of only acrylic polymer blocks.

The main chain of the acrylic block copolymer preferably comprises a polymer block having a glass transition temperature higher than 40 ° C. and a polymer block having a glass transition temperature lower than 20 ° C. With such a configuration, the adhesive composition has the property of low viscosity at a low temperature (for example, 100 to 120 ° C.), and is excellent in coatability. In the present specification, a polymer block having a glass transition temperature higher than 40 ° C. is referred to as a “hard block”, and a polymer block having a glass transition temperature lower than 20 ° C. is referred to as a “soft block”. The hard block more preferably has a glass transition temperature of 100 to 120 ° C. More preferably, the soft block has a glass transition temperature of -80 to -40.degree.

Preferably, the proportion of hard blocks is 7 to 50% by weight, the proportion of soft blocks is 50 to 93% by weight, and the proportion of hard blocks is 15 to 35% by weight, based on the total amount of the acrylic block copolymer. It is more preferable that the proportion of the soft block is 65 to 85% by weight. If the proportion of hard block is 7% by weight or more, the adhesive composition is less likely to cause penetration and bleeding even in a high temperature (50 ° C.) / High humidity (60% RH) environment, so that the storage stability is more excellent. Demonstrate the nature. Moreover, the adhesive composition also having the outstanding coatability is realizable because the ratio of the said hard block is 50 weight% or less.

The molecular weight of the acrylic block copolymer is preferably 10,000 to 400,000, more preferably 40,000 to 200,000, and still more preferably 40,000 to 120,000. When the molecular weight is 10,000 or more, the adhesive composition exhibits excellent storage stability without causing bleeding and bleeding even in a high temperature (50 ° C.) / High humidity (60% RH) environment Do. By the said molecular weight being 400,000 or less, an adhesive composition also combines the outstanding coatability.

The main chain of the acrylic block copolymer preferably has a structure represented by [A1]-[B]-[A2] or [A]-[B], and in [A1]-[B]-[A2] It is more preferred to have the structure shown. Here, the [A1], [A2] and [A] are polymer blocks (hard blocks) having a glass transition temperature higher than 40 ° C., and the [B] has a glass transition temperature lower than 20 ° C. It is a polymer block (soft block). Since the said acrylic block copolymer is water-insoluble and has a diblock structure or a triblock structure, the said adhesive composition is excellent in water resistance, heat resistance, oil retention, and is high temperature (50 degreeC) / high humidity. Excellent storage stability under (60% RH) environment. [A1] and [A2] may be the same polymer block or different polymer blocks, as long as they are polymer blocks having a glass transition temperature in the above range. The acrylic block copolymer may contain a multifunctional coupling agent such as a silane coupling agent as long as it has the above-described structure, but the acrylic block copolymer is preferably linear.

The above [A1], [A2] and [A] are not particularly limited as long as they are polymer blocks having a glass transition temperature in the above range, and examples thereof include methyl methacrylate, ethyl methacrylate, acrylonitrile, acrylamide, acrylic acid, and the like And polymer blocks derived from combinations of and the like. [A1], [A2] and [A] are preferably polymer blocks derived from methyl methacrylate because they are hard blocks having a high glass transition temperature.

The above [B] is not particularly limited as long as it is a polymer block having a glass transition temperature in the above range, but the above [B] is a polymer derived from an alkyl (meth) acrylate having 2 to 12 carbon atoms in the alkyl group. It is preferably a block. As the polymer block derived from the alkyl (meth) acrylate, for example, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, s-butyl acrylate, t-butyl acrylate, amyl acrylate, isoamyl acrylate, n-Hexyl (meth) acrylate, 2-ethylhexyl acrylate, lauryl acrylate, i-octyl acrylate, decyl methyl acrylate, cyclohexyl acrylate, nonyl acrylate, n-octyl (meth) acrylate, n-decyl methacrylate, n-dodecyl methacrylate, n Polymer block derived from tetradecyl methacrylate, isobornyl methacrylate, and combinations thereof And the like. [B] is preferably a polymer block derived from n-butyl acrylate, 2-ethylhexyl acrylate, and a combination thereof because it is a soft block having a low glass transition temperature.

The same alkyl (meth) acrylate monomer may be included in both the hard block and the soft block. The said acrylic block copolymer is hard block and soft as long as it does not prevent complete phase separation between the hard block and the soft block upon cooling, except for the hard block and the monomer constituting the soft block. It may be included in the block. As said other monomer, a vinyl monomer is mentioned, for example. In the present specification, the vinyl monomer may also include, for example, (meth) acrylate, vinyl ester, vinyl ether, styrene monomer, (meth) acrylamide and the like. The other monomer is preferably methyl methacrylate, butyl acrylate or 2-ethylhexyl acrylate.

The glass transition temperature (Tg) of the polymer block derived from alkyl (meth) acrylate means the glass transition temperature of a single polymer of each monomer constituting the polymer block derived from alkyl (meth) acrylate and the content ratio (weight The value obtained from the equation of Fox (FOX) is intended based on the fraction). The glass transition temperature of a single polymer can be, for example, the glass transition temperature described in “Adhesion technology handbook” of Nikkan Kogyo Shimbun.

The acrylic block copolymer preferably has a MFR value of 0 g / 10 min to 150 g / 10 min at 190 ° C. and a load of 2.16 kg measured according to ISO 1133, and more preferably 1 g / 10 min to 100 g / 10 min. When the MFR value of the acrylic block copolymer at 190 ° C. and 2.16 kg is 0 g / 10 min to 150 g / 10 min, seepage and bleeding occur even in a high temperature (50 ° C.) and high humidity (60% RH) environment Not exert excellent storage stability.

The proportion of the acrylic block copolymer is preferably 5 to 75% by weight, more preferably 10 to 40% by weight, based on 100% by weight of the adhesive composition. When the proportion of the acrylic block copolymer is 5% by weight or more, the adhesive composition is excellent in storage without bleeding and bleeding even in a high temperature (50 ° C.) / High humidity (60% RH) environment. Demonstrate stability. When the proportion of the acrylic block copolymer is 75% by weight or less, the adhesive composition also has excellent coatability.

<1-2. Surfactant>
The HLB value of the surfactant is preferably 3 to 20, and more preferably 5 to 19. If it is the said structure, the adhesive composition which is more excellent in compatibility can be provided. In the present specification, the HLB value is intended to be a value calculated by the Griffin equation shown below.

Examples of the surfactant include nonionic surfactants, ionic surfactants and amphoteric surfactants.

Examples of the nonionic surfactant include ester type, ether type, ester ether type, alkanolamide type and fluorine type. Examples of the ester type include glycerin fatty acid ester, sorbitan fatty acid ester and sucrose fatty acid ester. Examples of the ether type include polycondensate of polydimethylsiloxane group and alkylene oxide adduct, polysiloxane-polyoxyalkylene copolymer, polyoxyethylene lauryl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ether And polyoxyethylene polyoxypropylene block polymers. Examples of the ester ether type include polyethylene glycol fatty acid ester and polyoxyethylene sorbitan fatty acid ester. Examples of the alkanolamide type include aliphatic alkanolamides and the like. Examples of the fluorine type include perfluorodecanoic acid-diglycerin ester and perfluoroalkyl alkylene oxide compounds.

Examples of the ionic surfactant include anionic surfactants and cationic surfactants.

Examples of the anionic surfactant include hydrocarbon-based anionic surfactants, fluorine-based anionic surfactants, and silicone-based anionic surfactants having an anionic group. As said hydrocarbon type anionic surfactant, a carboxylic acid type, a sulfonic acid type, a sulfuric acid ester type, a phosphoric acid ester type, a borate ester type etc. are mentioned, for example. Examples of the carboxylic acid type include aliphatic monocarboxylates and N-acyloyl glutamates. Examples of the sulfonic acid type include alkyl benzene sulfonate, naphthalene sulfonate-formaldehyde condensate, and sulfosuccinic acid dialkyl ester. Examples of the sulfate ester type include alkyl sulfates and alkyl polyoxyethylene sulfates. As said phosphoric acid ester type | mold, a phosphoric acid alkyl salt etc. are mentioned, for example. As said boric-acid-ester type | mold, a boric-acid alkyl salt etc. are mentioned, for example. Examples of the fluorinated anionic surfactant include sodium perfluorodecanoate and sodium perfluorooctyl sulfonate. As a silicone type anionic surfactant which has the said anionic group, the polymer etc. which have a polydimethylsiloxane group and carboxylic acid metal salt are mentioned, for example.

Examples of the cationic surfactant include amine salt type and quaternary ammonium salt type. As said amine salt type, the alkylamine salt etc. are mentioned, for example. As said quaternary ammonium salt type, the alkyl trimethyl ammonium salt, the dialkyl dimethyl ammonium salt, the alkyl dimethyl benzyl ammonium salt etc. are mentioned, for example.

Examples of the amphoteric surfactant include betaine type and imidazoline type. Examples of the betaine type include dimethyl stearyl betaine, dimethyl lauryl betaine and dihydroxy lauryl betaine. Examples of the imidazoline type include di-sodium N-lauryl-p-iminodipropionate and the like.

The proportion of the surfactant is preferably 3 to 30% by weight, and more preferably 5 to 15% by weight with respect to 100% by weight of the adhesive composition. When the proportion of the surfactant is 3% by weight or more, it has excellent color-changing property, which can confirm a clear color change due to moisture. When the proportion of the surfactant is 30% by weight or less, the adhesive composition is excellent in storage without bleeding and bleeding even in a high temperature (50 ° C.) / High humidity (60% RH) environment. Demonstrate stability.

<1-3. Coloring reagent>
In the present specification, the term "coloring reagent" is intended to mean an agent whose hue changes with a chemical change, such as a pH indicator which is an indicator capable of changing color in response to a change in pH. The color reagent preferably has a color-changed region at pH 3-8, and more preferably has a color-changed region at pH 3-7. By virtue of this configuration, when the adhesive composition is acidic, reaction with moisture causes a color change from acidic to neutral. Specifically, the color reagent is preferably a pH indicator, and the pH indicator is methyl red, bromophenol blue, bromocresol green, bromocresol purple, methyl yellow, congo red, methyl orange, litmus, It is preferably at least one selected from the group consisting of bromothymol blue, cochineal dyes and anthocyanin dyes.

The proportion of the coloration reagent is preferably 0.01% by weight or more, and more preferably 0.1% by weight or more based on 100% by weight of the adhesive composition. If it is the said structure, the change of the color of the said coloring reagent can be visually confirmed. The upper limit of the content of the coloring reagent is not particularly limited, but from the viewpoint of maintenance of other properties such as heat stability, odor, compatibility and adhesion, and cost, 100 weight of the adhesive composition It is preferable that it is 3 weight% or less with respect to%.

<1-4. pH adjuster>
The pH adjuster is preferably an acidic material. The acidic material is not particularly limited as long as it can reduce the pH of the adhesive composition to less than 7, but an acid dissociation multiplier (pKa) is preferably 2 to 6, and a carboxyl group or phosphorus is preferable. It is more preferable that the material has an acid group such as an acid group, a phosphorous group, a sulfonic group, or a phenolic hydroxyl group in the molecule. With this configuration, the pH of the adhesive composition becomes acidic, and when it reacts with water, the pH becomes closer to neutral, and the difference in pH becomes large before and after the reaction with water. The change in color due to the reaction becomes large. Examples of the acidic material include fatty acids, hydroxy acids, aromatic carboxylic acids, dicarboxylic acids, tricarboxylic acids, rosin acids, maleic acids, phthalic acids and malic acids. Examples of the fatty acid include stearic acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, oleic acid, linoleic acid, linolenic acid, stearic acid, behenic acid, 12-hydroxystearic acid, isostearin Examples thereof include acids, undecynic acid, tall acid, eicosapentaenoic acid and docosahexaenoic acid. The pH adjuster may be a material having a function as another additive such as a tackifier and a softener.

The proportion of the pH adjuster is not particularly limited as long as the adhesive composition can be adjusted to a target pH, but it is preferably 3 to 90% by weight with respect to 100% by weight of the adhesive composition. .

<1-5. Other additives>
The adhesive composition may further contain an additive other than the above-described components, if necessary, as long as the color-changing property, storage stability, compatibility, coatability, and the like are not impaired. Examples of the additives include tackifiers, softeners, stabilizers, fillers, fluorescent agents, antioxidants, ultraviolet light absorbers, colorants, and the like.

The tackifier may be a natural system, a petroleum system, or a combination thereof, and examples thereof include rosin acid, rosin ester, hydrocarbon resin, synthetic polyterpene resin, natural terpene resin, and a combination thereof.

Moreover, as the tackifier, for example, rosin alcohol, methyl ester rosin, diethylene glycol ester rosin, glycerin ester rosin and partially hydrogenated rosin thereof, completely hydrogenated rosin or polymerized rosin, pentaerythritol ester and partially hydrogenated thereof Rosins, derivatives of rosins consisting of fully hydrogenated rosins or polymerized rosins and the like; derivatives of modified rosins; natural resins marketed under the trade names of gum rosins, wood rosins, tall oil rosins, etc .; modified rosins such as polymerized rosins, partially hydrogenated rosins; Polyterpene resins such as polymers of α-pinene, polymers of β-pinene, polymers of dipentene; terpene-modified products such as terpene-phenol copolymer, α-pinene-phenol copolymer; aliphatic petroleum resin; Family petroleum resin; cyclopentadiene resin; Group petroleum resin; phenol-based resins; alkylphenol - acetylene resin; a styrene resin; xylene resin; coumarone-indene resin; co critical condition such as the vinyl toluene and α- methyl styrene. When the tackifier has an acidic functional group, it also functions as a pH adjuster.

The proportion of the tackifier is not particularly limited, but is preferably 90% by weight or less based on 100% by weight of the adhesive composition.

The softening agent preferably has a melting point of 100 ° C. or less and a softening point of 90 ° C. or less, more preferably 80 ° C. or less, and still more preferably 70 ° C. or less. Most preferably, the temperature is not higher than ° C. By the said structure, the outstanding coating property which can apply | coat an adhesive agent composition directly to low heat resistant substances, such as a polyethylene film which is a constituent material of a paper diaper, is exhibited. The softener preferably has high compatibility with the acrylic block copolymer and is highly polar. Examples of the softener include fatty acids and derivatives thereof, waxes, and oils. As said fatty acid, the fatty acid mentioned above as said acidic material can be used, for example. As the waxes, for example, plant-derived waxes such as carnauba wax, candelilla wax, wood wax, rice wax and beeswax are preferably used. Examples of the oils include vegetable oils, animal oils, ester oils, alcohols, alkenyl succinic anhydrides, chlorinated paraffins and derivatives thereof (including hydrogenated oils). Examples of the vegetable oil include castor oil and castor oil. Examples of the ester oil include palm aliphatic ester, phthalic acid ester, adipic acid ester, sebacic acid ester and azelaic acid ester. Examples of the alcohol include polyalkylene glycols such as polyethylene glycol and polypropylene glycol, and glycerin diacetomonolaurate. When the softener is a fatty acid, it has a carboxyl group as a functional group, and thus also functions as a pH adjuster.

Examples of the stabilizer include 1,3,5-trimethyl 2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene and pentaerythrityl tetrakis-3- (3,5-). Di-t-butyl-4-hydroxyphenyl) propionate, pentaerythritol tetrakis (3-laurylthiodipropionate), n-octadecyl- (3,5-di-t-butyl-4-hydroxyphenol) propionate, 4, 4'-methylenebis (2,6-t-butylphenol), 4,4'-thiobis (6-t-butyl-o-cresol), 2,6-di-t-butylphenol, 6- (4-hydroxyphenoxy) -2,4-bis (n-octyl-thio) -1,3,5-triazine, di-n-octadecyl 3,5-di-t-butyl-4-hydride X-Benzyl-phosphonates, 2- (n-octylthio) ethyl 3,5-di-t-butyl-4-hydroxy-benzoate and sorbitol hexa [3- (3,5-di-t-butyl-4-hydroxyphenyl) ) -Propionate] and the like.

Examples of the filler include talc, calcium carbonate, clay silica, mica, wollastonite, feldspar, aluminum silicate, alumina, alumina hydrate, glass microspheres, ceramic microspheres, thermoplastic microspheres, bicrystals. Stone and wood flour etc. are mentioned.

<1-6. Method of producing adhesive composition>
The means for producing the adhesive composition is not particularly limited. For example, the above materials are mixed by heating and kneading using a melting tank, a roll, a Banbury mixer, a kneader, an extruder or the like. The method is mentioned.

[2. Absorbent article]
The adhesive composition according to an embodiment of the present invention can be suitably used for a water-absorbent article because it changes color in response to water such as urine. Therefore, a water-absorbent article comprising the adhesive composition according to an embodiment of the present invention is also included in the present invention. A water-absorbent article according to an embodiment of the present invention comprises an acrylic block copolymer, a surfactant, a coloring reagent, and a pH adjuster, and is at least partially made of an adhesive composition for indicating a wetness. It is coated. Regarding the adhesive composition, [1. The description overlapping with the contents described in the adhesive composition] will be omitted.

The water absorbent article according to one embodiment of the present invention is at least partially coated with the adhesive composition described above. Therefore, the water absorbent article is excellent in discoloration and storage stability. Specifically, when the adhesive composition contains the acrylic block copolymer excellent in water resistance, heat resistance and oil retention, the water absorbent article exhibits storage stability. When the adhesive composition contains the surfactant, the water absorbent article has hydrophilicity. As a result, water can be rapidly diffused in the adhesive composition, so that the color reagent can react to the presence of water. When the adhesive composition contains the coloring reagent, the water-absorbent article has a color-changing property. When the adhesive composition contains the pH adjuster, the water absorbent article reacts with a large amount of water such as urine while the reaction with a slight amount of water in the atmosphere is suppressed. The difference in color change before and after the reaction is greater.

As said water absorbent article, a disposable nonwoven fabric water absorbent article etc. are mentioned, for example. Examples of the disposable non-woven absorbent article include disposable diapers for children or adults, and pet sheets. Moisture such as urine changes the pH of the adhesive composition coated on a part of the water-absorbent article. The color change of the adhesive composition can indicate the presence of moisture.

The disposable non-woven absorbent article is not particularly limited. For example, a hydrophobic non-woven fabric, a back sheet such as polyethylene, a tissue paper, an absorbent body, a tissue paper, and a hydrophilic non-woven fabric are laminated in this order. It may be The adhesive composition is preferably coated on at least a portion of the backsheet. The range in which the adhesive composition is coated is preferably an area where a change in color can be confirmed visually. When used for children's or adult diapers and pet sheets, it is preferable that the side directly in contact with the skin is a hydrophilic non-woven fabric. According to the configuration, the disposable nonwoven absorbent article absorbs moisture such as urine without giving irritation to the skin, and leakage does not occur in a range not exceeding the absorption amount of the disposable nonwoven absorbent article.

As the pH adjuster, it is preferable to appropriately select one that does not easily irritate the skin.

The method for applying the adhesive composition to the disposable nonwoven absorbent article is not particularly limited, but a general hot melt adhesive application method can be used. For example, a die coater, a spray coating, a bead, a roll coater and a flexographic printing method etc. may be mentioned.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

Hereinafter, the present invention will be described in more detail by way of examples. The present invention is not limited to the following examples.

Example 1
20% by weight of a triblock copolymer of poly n-butyl acrylate (PnBA) and polymethyl methacrylate (PMMA) (hereinafter referred to as PMMA-PnBA-PMMA) (Klarity LA 2140, manufactured by Kuraray Co., Ltd., MFR (190 ° C.) 2.16 kg): 31 g / 10 min), 8% by weight of polyoxyethylene lauryl ether (DKS NL-80, Dai-ichi Kogyo Seiyaku Co., Ltd., HLB value: 12.9), 0.15% by weight of bromocresol Green (manufactured by Wako Pure Chemical Industries, Ltd., color change range: pH 3.8 to 5.4), 7% by weight of stearic acid (stearic acid 48, manufactured by Miyoshi Yushi Co., Ltd., acid value: 207 mg KOH / g), 14 weight % Rosin acid (Chinese rosin X, manufactured by Arakawa Chemical Industries, Ltd., acid value: 168 mg KOH / g), 25 weight Hydrogenated castor oil (hydrogenated castor oil, manufactured by Ito Oil Co., Ltd.), 25.85% by weight of rosin ester (Superester A-75, manufactured by Arakawa Chemical Industries, Ltd.) at 180 ° C. in a heating kneader To make a 100% by weight adhesive composition.

Example 2
Instead of PMMA-PnBA-PMMA (MFR (190 ° C., 2.16 kg): 31 g / 10 min), PMMA-PnBA-PMMA (Klarity LA 4285, manufactured by Kuraray Co., Ltd., MFR (190 ° C., 2.16 kg)): 1. An adhesive composition was produced in the same manner as in Example 1 except that 5 g / 10 min) was used.

[Example 3]
An adhesive composition was produced in the same manner as in Example 1 except that 70.85% by weight of PMMA-PnBA-PMMA was used and castor hydrogenated oil and rosin ester were not added.

Example 4
An adhesive composition was produced in the same manner as in Example 1 except that the amount of PMMA-PnBA-PMMA was 5% by weight and the amount of rosin ester was 40.85% by weight.

[Example 5]
PMMA-PnBA-PMMA is 30% by weight, 40.85% by weight of a diblock copolymer of PnBA and PMMA (hereinafter referred to as PnBA-PMMA) (Klarity LA 1114, manufactured by Kuraray Co., Ltd., viscosity (160 ° C.): An adhesive composition was produced in the same manner as in Example 1 except that 5,000 mPa · s) was further added and castor hydrogenated oil and rosin ester were not added.

[Example 6]
An adhesive composition was prepared in the same manner as in Example 1 except that the polyoxyethylene lauryl ether was 3% by weight and the rosin ester was 30.85% by weight.

[Example 7]
An adhesive composition was prepared in the same manner as in Example 1 except that the polyoxyethylene lauryl ether was 30% by weight and the rosin ester was 3.85% by weight.

Example 8
An adhesive composition was produced in the same manner as in Example 1 except that PnBA-PMMA (MFR (190 ° C., 2.16 kg): 11.4 g / 10 min) was used instead of PMMA-PnBA-PMMA.

[Example 9]
A polymer block (P (2EHA-co-nBA)) randomly copolymerized with 2-ethylhexyl acrylate (2EHA) and n-butyl acrylate (nBA) instead of PMMA-PnBA-PMMA, and a triblock of PMMA Bonding in the same manner as in Example 1 except that a copolymer (hereinafter referred to as PMMA-P (2EHA-co-nBA) -PMMA) (MFR (190 ° C., 2.16 kg): 3.8 g / 10 min) was used The agent composition was made.

[Example 10]
It is carried out except using polyoxyethylene lauryl ether (DKS NL-15, Dai-ichi Kogyo Seiyaku Co., Ltd., HLB value: 5.1) instead of polyoxyethylene lauryl ether (HLB value: 12.9). An adhesive composition was prepared as in Example 1.

[Example 11]
It was carried out except using polyoxyethylene lauryl ether (DKS NL-600F, Dai-ichi Kogyo Seiyaku Co., Ltd., HLB value: 18.6) instead of polyoxyethylene lauryl ether (HLB value: 12.9). An adhesive composition was prepared as in Example 1.

[Example 12]
An adhesive composition was prepared in the same manner as in Example 1 except that bromophenol blue (manufactured by Wako Pure Chemical Industries, Ltd., color change range: pH 3.0 to 4.6) was used instead of bromocresol green. did.

[Example 13]
An adhesive composition was prepared in the same manner as Example 1 except that methyl red (Wako Pure Chemical Industries, Ltd., color change range: pH 4.4 to 6.2) was used instead of bromocresol green. .

Comparative Example 1
An adhesive composition was produced in the same manner as in Example 1 except that polyethylene glycol (PEG) (PEG 20000, manufactured by Kishida Chemical Co., Ltd.) was used instead of PMMA-PnBA-PMMA.

Comparative Example 2
Triblock copolymer (SBS) of styrene and butadiene instead of PMMA-PnBA-PMMA (Asaprene T-420, manufactured by Asahi Kasei Co., Ltd., styrene: 30% by weight, MFR (190 ° C., 2.16 kg): 1.1 g An adhesive composition was produced in the same manner as in Example 1 except that (/ 10 min) was used.

Comparative Example 3
An adhesive composition was produced in the same manner as in Example 1 except that PnBA (Alphon UP 1000, manufactured by Toagosei Co., Ltd.) was used instead of PMMA-PnBA-PMMA.

Comparative Example 4
A random copolymer of ethylene and methyl methacrylate (EMMA) (Aclift CM5022, manufactured by Sumitomo Chemical Co., Ltd., MFR (190 ° C., 2.16 kg): 450 g / 10 min) is used instead of PMMA-PnBA-PMMA. An adhesive composition was prepared in the same manner as Example 1.

Comparative Example 5
An adhesive composition was prepared in the same manner as in Example 1 except that the rosin ester content was 33.85% by weight, and polyoxyethylene lauryl ether was not added.

Comparative Example 6
An adhesive composition was prepared in the same manner as in Example 1 except that the rosin ester content was 26% by weight and bromocresol green was not added.

The compositions of the adhesive compositions prepared in Examples 1 to 13 and Comparative Examples 1 to 6 are shown in Tables 1 and 2.

〔Test method〕
<1. Color change>
FIG. 1 shows a cross-sectional view of the configuration of a hue change test apparatus for evaluating the color change of an adhesive composition. As shown in FIG. 1, a glass plate, a polyethylene (PE) film having a thickness of 20 μm, an adhesive composition having a thickness of 20 to 30 μm, and a cotton puff (made by Cotton Lab Co., Ltd.) are installed in this order from the bottom. 200 μL of pure water was dropped from above the cotton puff, and after 1 and 2 minutes, the color change of the adhesive composition through the glass plate and the PE film was visually confirmed and evaluated according to the following criteria.
◎: The state in which the color of the adhesive composition is totally changed from the original color to a different color after 1 minute.
○: The color of the adhesive composition is changed from the original color to a different color after 2 minutes.
X: The color of the adhesive composition has not changed from the original color after 2 minutes.

<2. Storage stability>
<1. Using the apparatus used in the evaluation of “color change”, the sample was allowed to stand in an environment of temperature 50 ° C. and humidity 60 RH%, and after 24 hours, the state was visually confirmed and evaluated according to the following criteria.
A: After 24 hours, even if the temperature is raised to 60 ° C., transfer of the adhesive composition component to the cotton puff surface, oil stain of the PE film, and stain leakage of the adhesive composition component passing through the PE film There is no condition.
Good: Transfer of adhesive composition component to cotton puff surface, oil stain of PE film, and no stain of adhesive composition component having passed through PE film.
X: A state in which there is at least one of transfer of the adhesive composition component to the cotton puff surface, oil stain of PE film, and adhesive composition component having passed through the PE film.

<3. Compatibility>
50 g of the adhesive composition was charged into a 100 mL beaker, and was allowed to stand in a thermostat heated to 180 ° C. After 2 hours, the molten state of the adhesive composition was visually confirmed and evaluated according to the following criteria.
○: No separation of the solution, no precipitate and no sludge generation.
X: Condition in which there is at least one of separation of solution, generation of precipitate and sludge.

〔result〕
The test results of the samples produced in Examples 1 to 13 and Comparative Examples 1 to 6 are shown in Table 3 below.

From the above results, it was recognized that the adhesive composition of each example is excellent in color change, storage stability and compatibility. The adhesive compositions of Examples 3 and 5 were found to be superior in storage stability to other adhesive compositions due to the high proportion of acrylic block copolymer and high oil retention. The adhesive compositions of Examples 2 and 9 were also found to be superior in storage stability to the adhesive compositions of the other examples because the MFR value of the acrylic block copolymer is small. The adhesive composition of Example 7 was found to be more excellent in discoloration than other adhesive compositions because it had a high proportion of surfactant and high hydrophilicity.

The adhesive compositions of Comparative Examples 5 and 6 showed no discoloration after 2 minutes of dropping. After 24 hours, the adhesive compositions of Comparative Examples 1 to 4 were found to have a bleed and stain state to the PE film. In the adhesive composition of Comparative Example 2, separation of the solution was also observed. In particular, Comparative Example 4 is considered to be inferior in storage stability because it uses a random copolymer having a large MFR value.

The present invention can be suitably used for disposable nonwoven absorbent articles such as children's or adult paper diapers and pet sheets.

Claims

An adhesive composition for indicating wetness, which comprises an acrylic block copolymer, a surfactant, a coloring reagent, and a pH adjuster.
The main chain of the acrylic block copolymer is
A polymer block having a glass transition temperature above 40 ° C.
A polymer block having a glass transition temperature below 20 ° C .;
The adhesive composition according to claim 1, comprising:
The main chain of the acrylic block copolymer is
[A1]-[B]-[A2] or [A]-[B]
Has the structure shown by
The above [A1], [A2] and [A] are polymer blocks having a glass transition temperature higher than 40 ° C.,
The adhesive composition according to claim 2, wherein the [B] is a polymer block having a glass transition temperature lower than 20 ° C.
The above [A1], [A2] and [A] are polymer blocks derived from methyl methacrylate,
The adhesive composition according to claim 3, wherein the [B] is a polymer block derived from an alkyl (meth) acrylate in which the alkyl group has 2 to 12 carbon atoms.
The adhesive composition according to any one of claims 1 to 4, wherein the proportion of the acrylic block copolymer is 5 to 75% by weight with respect to 100% by weight of the adhesive composition.
The adhesive composition according to any one of claims 1 to 5, wherein the HLB value of the surfactant is 3 to 20.
The adhesive composition according to any one of claims 1 to 6, wherein a ratio of the surfactant is 3 to 30% by weight with respect to 100% by weight of the adhesive composition.
The adhesive composition according to any one of claims 1 to 7, wherein the color change reagent has a color change area at a pH of 3 to 8.
The color reagent is at least one selected from the group consisting of methyl red, bromophenol blue, bromocresol green, bromocresol purple, methyl yellow, congo red, methyl orange, litmus, bromothymol blue, cochineal dye and anthocyanin dye. Adhesive composition according to any one of the preceding claims, characterized in that it is of the type.
The adhesive composition according to any one of claims 1 to 9, wherein a proportion of the coloration reagent is 0.01% by weight or more based on 100% by weight of the adhesive composition. .
The adhesive composition according to any one of claims 1 to 10, wherein the pH adjuster is an acidic material.
A water absorbent article at least partially coated with the adhesive composition according to any one of claims 1 to 11.