JP6403379B2 - Acrylic resin emulsion for hairdressing agent, hairdressing agent containing the same, and hairdressing method - Google Patents

Description

  The present invention relates to an acrylic resin emulsion useful for a hair styling agent (hair styling agent).

There are various types of hairdressing agents such as liquid, gel, foam, mist, cream and wax.
Usually, hair styling agents are based on a polymer (set polymer) for maintaining a desired shape by forming a film on the hair surface, and depending on the additives and dosage forms applied for various purposes. A polymer composition containing a solvent, a base, and the like. In recent years, hair styling agents can be freely arranged at the time of hair styling, and hair creams and hair waxes, which are emulsifiers using oil and water, have become mainstream as dosage forms that can be easily modified after styling. Yes.

  In addition, hairdressing agents are required to have performance in styling (conditioning hair) such as the ability to give the hair a desired shape and hold it for a long time, excellent appearance performance, and excellent tactile feel. In addition, the convenience of washing and removing the hairdressing agent from the hair after use is also required as a performance, and various hairdressing agents have been developed.

  For example, Patent Document 1 describes an aqueous hair styling agent using a polyvinyl alcohol-based resin having a specific structure as a main component of a polymer component as a main ingredient. Patent Document 2 describes beeswax and an interface. A hair cosmetic is described in which polyvinyl alcohol is blended as a blending agent in an emulsion composition comprising an active agent and water.

Japanese Unexamined Patent Publication No. 2009-286724 Japanese Unexamined Patent Publication No. 2011-148721

The hair styling agent of the above-mentioned patent document 1 has the performance that the polyvinyl alcohol-based resin having a specific structure has a good curl holding power under high humidity conditions, has less stickiness, has a moisturizing power, and has little damage to hair. In addition, the hairdressing agent of Patent Document 2 described above improves the aesthetics at the time of use by blending a polyvinyl alcohol-based resin in the emulsion composition, and does not impart unnatural shine to the hair after application. It calls for performance. However, the hair styling agent described in Patent Document 1 still has room for improvement in terms of poor hand-comb (finger), comb, brush, and the like, and the point of re-styling when hair is broken once. Further, the hair styling agent described in Patent Document 2 has a large stickiness and a poor usability, and further improvement is required.
In addition, hair styling agents are required to be easily washed after use, but when exposed to moisture, sweat, rain, etc., the hair styling flows down and the hair styling collapses, the forehead and cheeks are sticky, Since there should be no inconveniences such as inability to re-hair, it was also necessary to have an appropriate performance for washing.

  Therefore, in the present invention, under such a background, an acrylic that is effectively used as a hair styling agent having a good balance between styling performance (hair styling performance (setting power), re-hair styling performance (re-setting power), tactile sensation) and washing performance. The purpose is to provide a resin emulsion.

  However, as a result of intensive studies in view of such circumstances, the present inventors have used a polyvinyl alcohol resin, which has been conventionally used as a main polymer or as a compounding agent, as a dispersion stabilizer for an acrylic resin. Found that the hair-styling agent containing the emulsion obtained by the above has excellent balance between styling performance (hair-styling performance (setting power), re-hair-styling performance (re-setting power), tactile sensation) and washable performance, and completed the present invention. .

（式（１）中、Ｒ ¹ 〜Ｒ ⁶ はそれぞれ独立して水素原子又は有機基を表し、Ｘは単結合又は結合鎖を示す。）
That is, the gist of the present invention includes an acrylic resin (A) dispersed and stabilized by a polyvinyl alcohol resin [I] , and the polyvinyl alcohol resin [I] is represented by the following general formula (1). It is a polyvinyl alcohol resin containing a chain 1,2-diol structural unit, and the acrylic resin (A) contains 40 wt% or more of an aliphatic (meth) acrylate monomer having an alkyl group with 4 to 12 carbon atoms. The present invention relates to an acrylic resin emulsion for hairdressing agent , which is obtained by polymerizing the monomer component to be contained, and has a glass transition temperature of -80 to 0 ° C. of the acrylic resin (A). .

(In Formula (1), R < ¹ > -R < ⁶ > represents a hydrogen atom or an organic group each independently, and X shows a single bond or a bond chain.)

  Further, the present invention relates to a hair styling agent and a hair styling method using the acrylic resin emulsion for hair styling agent.

  Since the acrylic resin emulsion for hairdressing agents of the present invention is excellent in water-solubility and / or redispersibility in water, the hairdressing agent using such an acrylic resin emulsion for hairdressing agents is excellent in cleaning performance. And has an excellent balance with styling performance.

The present invention will be described in detail below, but these show examples of desirable embodiments.
In the present invention, (meth) acryl means acryl or methacryl, (meth) acryloyl means acryloyl or methacryloyl, and (meth) acrylate means acrylate or methacrylate. It is a resin obtained by polymerizing a monomer component containing at least one (meth) acrylic monomer.

  The acrylic resin emulsion for hairdressing agents of the present invention contains an acrylic resin (A) dispersed and stabilized by a polyvinyl alcohol resin (hereinafter sometimes referred to as “PVA resin”) [I]. It is.

  In the present invention, the dispersion-stabilized state refers to a dispersion state in which the emulsion is not settled and separated even if it is allowed to stand at 23 ° C. for 1 month, and is kept in a uniform state.

<Polyvinyl alcohol resin [I]>

  As said PVA-type resin [I], the PVA-type resin which has the following specific average saponification degree and average polymerization degree is preferable.

The average degree of saponification of the PVA resin [I] is preferably 70 to 99.9 mol%, particularly preferably 80 to 99.5 mol%, and more preferably 85 to 99.0 mol%. .
When the average degree of saponification is too low, it is difficult for the polymerization to proceed stably, and even when the polymerization is completed, there is a tendency that the storage stability of the emulsion is lowered, the emulsion stability is too high, and the production is There is a tendency to become difficult.

  In the present invention, the average saponification degree can be determined according to the saponification degree calculation method described in JIS K 6726 (1994).

The average degree of polymerization of the PVA resin [I] is preferably 50 to 3,000, particularly preferably 100 to 2,000, more preferably 200 to 1,000, Preferably it is 200-500.
If the average degree of polymerization is too low, the protective colloid ability at the time of emulsion polymerization will be insufficient and the polymerization will tend not to proceed stably.If it is too high, the reaction system will become unstable due to thickening during the polymerization. Dispersion stability tends to decrease.

  In the present invention, the average degree of polymerization can be determined according to the method for calculating the average degree of polymerization described in JIS K 6726 (1994).

  In the present invention, PVA-based resin [I] means PVA itself or, for example, one modified by various modified species, and the degree of modification is usually 20 mol% or less, preferably 15 mol% or less, More preferably, it is 10 mol% or less.

  Examples of the modified PVA resin include an anion modified PVA resin modified with an anionic group including a carboxylic acid group, a sulfonic acid group, and a phosphoric acid group, and modified with a cationic group such as a quaternary ammonium group. Cationic modified PVA resin, modified PVA resin modified with various functional groups such as acetoacetyl group, diacetone acrylamide group, mercapto group, silanol group, etc., and 1,2-diol structural unit in side chain PVA-based resin to be used.

The PVA resin [I] in the present invention is a PVA resin containing a side chain 1,2-diol structural unit represented by the following general formula (1), when the acrylate monomer is polymerized. , not preferable in terms of dispersion stability is excellent.

(In formula (1), R ^{1 to} R ⁶ each independently represents a hydrogen atom or an organic group, and X represents a single bond or a bond chain.)

In the general formula (1), R ^{1 to} R ⁶ each independently represent a hydrogen atom or an organic group. R ^{1 to} R ⁶ are preferably all hydrogen atoms, but may be organic groups as long as the resin properties are not significantly impaired. Although it does not specifically limit as this organic group, For example, C1-C4 alkyl groups, such as a methyl group, an ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, are preferable, You may have substituents, such as a halogeno group, a hydroxyl group, an ester group, a carboxylic acid group, and a sulfonic acid group, as needed.

In the general formula (1), X is a single bond or a bonded chain, and is preferably a single bond from the viewpoints of set retention, non-stickiness, familiarity with hair, and the like. The bonding chain is not particularly limited, but other hydrocarbons such as alkylene, alkenylene, alkynylene, phenylene, naphthylene (these hydrocarbons may be substituted with halogen such as fluorine, chlorine, bromine, etc.) , —O—, — (CH ₂ O) _m —, — (OCH ₂ ) _m —, — (CH ₂ O) _m CH ₂ —, —CO—, —COCO—, —CO (CH ₂ ) _m CO— _{, -CO (C 6 H 4)} CO -, - S -, - CS -, - SO -, - SO 2 -, - NR -, - CONR -, - NRCO -, - CSNR -, - NRCS -, - _{NRNR -, - HPO 4 -,} - Si (OR) 2 -, - OSi (OR) 2 -, - OSi (OR) 2 O -, - Ti (OR) 2 -, - OTi (OR) 2 -, - _{OTi (OR) 2 O -,} - Al (OR) -, - OAl ( R) -, - OAl (OR) O- and the like (R is each independently optional substituents, a hydrogen atom, an alkyl group preferably, and m is a natural number). Among these, an alkylene group having 6 or less carbon atoms, particularly a methylene group, or —CH ₂ OCH ₂ — is preferable from the viewpoint of viscosity stability during production, heat resistance, and the like.

  The PVA resin containing the 1,2-diol structural unit represented by the formula (1) is, for example, (I) a method for saponifying a copolymer of vinyl acetate and 3,4-diacetoxy-1-butene , (II) a method of saponifying and decarboxylating a copolymer of vinyl acetate and vinyl ethylene carbonate, and (III) a copolymer of vinyl acetate and 2,2-dialkyl-4-vinyl-1,3-dioxolane. Can be obtained by a method of saponifying and deketalizing, and (IV) a method of saponifying a copolymer of vinyl acetate and glyceryl monoallyl ether.

The content of the 1,2-diol structural unit in the PVA-based resin containing the 1,2-diol structural unit represented by the formula (1) is preferably 1 to 15 mol%, particularly preferably 1 to It is 12 mol%, more preferably 2 to 10 mol%, particularly preferably 2 to 9 mol%.
If the content of the 1,2-diol structural unit is too low, the mechanical stability of the emulsion tends to be lowered. If it is too high, the stability during polymerization is lowered, and a stable emulsion having a high nonvolatile content can be obtained. There is a tendency to become difficult.

In addition, the content of the side chain 1,2-diol unit in the PVA resin is determined from ¹ H-NMR spectrum (solvent: DMSO-d6, internal standard: tetramethylsilane) of PVA completely saponified. Specifically, it can be calculated from the peak area derived from the hydroxyl proton, methine proton, and methylene proton in the 1,2-diol unit, the methylene proton in the main chain, the proton in the hydroxyl group linked to the main chain, etc. Good.

The average saponification degree of the PVA resin containing the 1,2-diol structural unit represented by the formula (1) is preferably 85 mol% or more, more preferably 86.5 to 99.8 mol. %, Particularly preferably 95 to 99 mol%.
If the degree of saponification is too small, the stability of the emulsion during polymerization tends to decrease, making it difficult to obtain the desired emulsion.

Furthermore, the average degree of polymerization of the PVA resin containing the 1,2-diol structural unit represented by the formula (1) is preferably 50 to 3,000, more preferably 100 to 2,500, and still more preferably 200 to 2,000, particularly preferably 200 to 500.
If the average degree of polymerization is too small, it tends to be difficult to produce a PVA resin industrially, and if it is too large, the viscosity of the emulsion tends to be too high, or the polymerization stability of the emulsion tends to decrease.

  In the present invention, the PVA resin [I] is usually made into an aqueous solution using an aqueous medium, and this is used in the process of emulsion polymerization. Here, the aqueous medium refers to water or an alcoholic solvent mainly composed of water, preferably water.

  The amount (nonvolatile content) of the PVA-based resin [I] in the aqueous solution is not particularly limited, but is preferably 5 to 30% by weight from the viewpoint of easy handling.

<Acrylic resin (A)>
The acrylic resin (A) in the present invention is obtained by polymerizing a monomer component containing the (meth) acrylic monomer (a1) as a main component.
The main component is preferably 40% by weight or more, more preferably 50% by weight or more, particularly preferably 60% by weight or more, and further preferably 70% by weight or more based on the whole monomer component.

Examples of the (meth) acrylic monomer (a1) include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, and t-butyl (meth) acrylate. , 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, lauryl (meth) acrylate, octyl (meth) acrylate, stearyl (meth) acrylate, and other aliphatic (meth) acrylate monomers, and phenoxy (meth) acrylate And aromatic (meth) acrylate monomers such as trifluoroethyl (meth) acrylate. In addition, these can be used individually or in combination of 2 or more types.
Among these, from the viewpoint of the hair bundle feeling and restyled, the number of carbon atoms of A alkyl group 4 to 12 aliphatic (meth) acrylate monomer is important, particularly preferably n- butyl acrylate, 2- Ethyl hexyl acrylate. Moreover, the combined use of 2-ethylhexyl acrylate and methyl methacrylate or the combined use of n-butyl acrylate and methyl methacrylate can be suitably used.

Further, the functional group-containing monomer (a2) may be copolymerized with the (meth) acrylic monomer (a1). As the functional group-containing monomer (a2), for example, two or more vinyl groups are included in the molecular structure. And the like, a glycidyl group-containing monomer, an allyl group-containing monomer, a hydrolyzable silyl group-containing monomer, an acetoacetyl group-containing monomer, a hydroxyl group-containing monomer, a carboxyl group-containing monomer, and the like.
Among these, it is preferable to copolymerize a monomer having two or more vinyl groups or a hydrolyzable silyl group-containing monomer in the molecular structure from the viewpoint of improving the washing performance without degrading the hairstyling property.

Examples of the monomer having two or more vinyl groups in the molecular structure include divinylbenzene, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, ethylene glycol di (meth) acrylate, 1,2-propylene glycol di ( (Meth) acrylate, 1,3-propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, tri Examples include methylolpropane tri (meth) acrylate and allyl (meth) acrylate.
Among these, ethylene glycol di (meth) acrylate, 1,2-propylene glycol di (meth) acrylate, 1,3-propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, neopentylglycol di (meth) acrylate, and trimethylolpropane tri (meth) acrylate are preferable in terms of good copolymerizability with the (meth) acrylate monomer.

  Examples of the glycidyl group-containing monomer include glycidyl (meth) acrylate, glycidyl (meth) allyl ether, 3,4-epoxycyclohexyl (meth) acrylate, and the like.

  Examples of the allyl group-containing monomer include monomers having two or more allyl groups such as triallyloxyethylene, diallyl maleate, triallyl cyanurate, triallyl isocyanurate, tetraallyloxyethane, allyl glycidyl ether, and allyl acetate. Etc.

Examples of the hydrolyzable silyl group-containing monomer include vinyl-based silyl group-containing monomers such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, and vinylmethyldimethoxysilane; γ- (meth) (Meth) acryloxy systems such as acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, γ- (meth) acryloxypropylmethyldiethoxysilane Examples thereof include silyl group-containing monomers.
Among these, a (meth) acryloxy-based silyl group-containing monomer is preferable in terms of excellent copolymerizability with the (meth) acrylate-based monomer (a1).

  Examples of the acetoacetyl group-containing monomer include acetoacetate vinyl ester, acetoacetate allyl ester, diacetoacetate allyl ester, acetoacetoxyethyl (meth) acrylate, acetoacetoxyethyl crotonate, acetoacetoxypropyl (meth) acrylate, acetoacetoxy Examples thereof include propyl crotonate and 2-cyanoacetoacetoxyethyl (meth) acrylate.

  Examples of the hydroxyl group-containing monomer include (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate, and protection during emulsion polymerization. From the viewpoint of colloidal action and water washability, 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate are preferred.

  Examples of the carboxyl group-containing monomer include (meth) acrylic acid, acrylic acid dimer, crotonic acid, maleic acid, maleic anhydride, fumaric acid, citraconic acid, glutaconic acid, itaconic acid, acrylamide N-glycolic acid, and cinnamon. Among these, acrylic acid and methacrylic acid are preferable from the viewpoint of protective colloidal action and water washability during emulsion polymerization.

The content ratio of the functional group-containing monomer (a2) is preferably 0.01 to 10% by weight, particularly preferably 0.05 to 5% by weight, more preferably, based on the entire monomer component. 0.1 to 3% by weight.
If the content is too high, the acrylic resin becomes too hard and sufficient adhesive force does not appear and hair styling tends to be reduced. If the content is too low, the effect of washing properties tends to be difficult to understand.

  Further, when the functional group-containing monomer (a2) is a monomer having two or more vinyl groups in the molecular structure, it is preferably 0.01 to 5% by weight based on the whole monomer component, Especially preferably, it is 0.05 to 3 weight%, More preferably, it is 0.1 to 1 weight%.

  In addition, a small amount of styrene monomer such as styrene and α-methylstyrene, vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, pivalin within the range not impairing the effects of the present invention. Vinyl ester monomers such as vinyl acid, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl versatate, vinyl 2-ethylhexanoate and the like may be used.

  In the acrylic resin emulsion according to the present invention, in addition to the above-mentioned monomer components, other components can be further used as necessary. Such other components can be appropriately selected depending on the purpose, and examples thereof include a polymerization initiator, a polymerization regulator, an auxiliary emulsifier, and a plasticizer.

As the polymerization initiator, those that can be used for usual emulsion polymerization can be used, for example, inorganic peroxides such as potassium persulfate, sodium persulfate, and ammonium persulfate; organic peroxides, azo-based initiators, peroxides Examples thereof include peroxides such as hydrogen and butyl peroxide; and redox polymerization initiators obtained by combining these with reducing agents such as acidic sodium sulfite and L-ascorbic acid. These may be used alone or in combination of two or more.
Among these, ammonium persulfate and potassium persulfate are preferable in terms of easy polymerization.

  As said polymerization regulator, it can select suitably from well-known things. Examples of such a polymerization regulator include a chain transfer agent and a buffer.

  Examples of the chain transfer agent include alcohols such as methanol, ethanol, propanol, and butanol; aldehydes such as acetaldehyde, propionaldehyde, n-butyraldehyde, furfural, and benzaldehyde; and dodecyl mercaptan, lauryl mercaptan, normal mercaptan, thiol, and the like. And mercaptans such as glycolic acid, octyl thioglycolate, and thioglycerol. These may be used alone or in combination of two or more. The use of a chain transfer agent is effective in that the polymerization is performed stably, and it is desirable to use it to adjust the degree of polymerization of the acrylic resin.

  Examples of the buffer include sodium acetate, ammonium acetate, dibasic sodium phosphate, sodium citrate and the like. These may be used alone or in combination of two or more.

  Any auxiliary emulsifier can be used as long as it is known to those skilled in the art as being usable for emulsion polymerization. Therefore, auxiliary emulsifiers are, for example, known anionic, cationic and nonionic surfactants, water-soluble polymers having protective colloid ability other than PVA resin [I], and water-soluble oligomers. Can be selected as appropriate.

  Examples of the surfactant include anionic surfactants such as sodium lauryl sulfate and sodium dodecylbenzenesulfonate, and nonionic surfactants such as those having a pluronic structure and those having a polyoxyethylene structure. Agents. Moreover, the reactive surfactant which has a radically polymerizable unsaturated bond in a structure can also be used as a surfactant. These may be used alone or in combination of two or more.

  The use of the surfactant has an effect of facilitating the emulsion polymerization smoothly, making it easy to control (effect as an emulsifier), and suppressing the generation of coarse particles and block-like substances generated during the polymerization. However, if many of these surfactants are used as emulsifiers, the graft rate tends to decrease. For this reason, when using a surfactant, it is desirable that the amount used is auxiliary to the PVA resin [I], that is, as small as possible.

  Examples of the water-soluble polymer having protective colloid ability other than the PVA-based resin [I] include PVA-based resins other than the PVA-based resin [I], hydroxyethyl cellulose, polyvinyl pyrrolidone, methyl cellulose, and the like. These may be used alone or in combination of two or more. These are effective in that the viscosity is changed by increasing the viscosity of the emulsion or changing the particle size of the emulsion.

  As said water-soluble oligomer, the polymerization degree which has hydrophilic groups, such as a sulfonic acid group, a carboxyl group, a hydroxyl group, and an alkylene glycol group, is preferable, for example, About 10-500 polymers or copolymers are mentioned suitably. . Specific examples of the water-soluble oligomer include, for example, amide copolymers such as 2-methacrylamide-2-methylpropanesulfonic acid copolymer, sodium methacrylate-4-styrenesulfonate copolymer, styrene / maleic acid copolymer. Examples include polymers, melamine sulfonic acid formaldehyde condensates, poly (meth) acrylates, and the like. Furthermore, specific examples include a monomer having a sulfonic acid group, a carboxyl group, a hydroxyl group, an alkylene glycol group or the like, a water-soluble oligomer obtained by copolymerizing a radical polymerizable reactive emulsifier in advance alone or with another monomer, and the like. It is done. These may be used alone or in combination of two or more.

  As the plasticizer, an adipate plasticizer, a phthalic acid plasticizer, a phosphoric acid plasticizer, or the like can be used.

  The usage-amount of these other components can be suitably selected according to the objective in the range which does not impair the effect of this invention.

<Method for producing acrylic resin emulsion>
Below, the manufacturing method of the acrylic resin emulsion of this invention is demonstrated.

  The acrylic resin emulsion of the present invention can be produced, for example, by emulsion polymerization of the above monomer components using PVA resin [I] as a dispersion stabilizer. In this polymerization process, an acrylic resin emulsion using the dispersion stabilized acrylic resin (A) as a dispersoid is produced using PVA resin [I] as a dispersion stabilizer.

In this invention, it is preferable that the usage-amount of PVA-type resin [I] is 0.01-40 weight part with respect to 100 weight part of the whole monomer component which comprises acrylic resin (A), especially. Preferably it is 0.1-30 weight part, More preferably, it is 0.5-20 weight part.
If the amount of the PVA resin [I] used is too small, the amount of protective colloid at the time of emulsion polymerization will be insufficient, and the polymerization stability tends to decrease. The viscosity of the resin emulsion tends to increase and the stability tends to decrease.

  Here, the PVA resin [I] used is usually present in the entire amount in the acrylic resin emulsion formed by polymerization.

  Usually, emulsion polymerization is carried out using the above-described other components such as a polymerization initiator, a polymerization regulator, and an auxiliary emulsifier as needed in addition to the PVA resin [I] and the monomer component. The polymerization reaction conditions can be appropriately selected according to the type and purpose of the monomer.

As a method of emulsion polymerization, for example, water and PVA-based resin [I] are charged into a reaction can, and a monomer dropping type emulsion polymerization method in which a monomer component and a polymerization initiator are dropped by raising the temperature; The mixed monomer of the monomer component is dispersed and emulsified in advance with water-soluble polymer having protective colloid ability other than PVA resin [I] and / or PVA resin [I] and water, and then dispersed and emulsified. An emulsified monomer dropping type emulsion polymerization method in which a monomer is dropped, and the like. The emulsified monomer dropping type polymerization method is advantageous in terms of reactivity when using a hydrophobic monomer, management and controllability of the polymerization process, and the like.
In addition, it has protective colloid ability other than PVA-based resin [I] and / or PVA-based resin [I] at the end of the polymerization reaction in order to impart stability of the emulsion and water-dispersibility and / or re-dispersibility in water. It is also possible to add a water-soluble polymer later.

  The emulsion polymerization process will be described more specifically as follows.

  In the monomer dropping emulsion polymerization, for example, first, water, PVA resin [I], and an auxiliary emulsifier as necessary are charged into a reaction can, and this is heated (usually 40 to 90 ° C.), then the monomer A part of the components and a polymerization initiator are added to the reaction vessel to carry out initial polymerization. Next, the remaining monomer components are added to the reaction can while dropping all at once, and the polymerization is allowed to proceed while further adding a polymerization initiator as necessary. When it is determined that the polymerization reaction is completed, the reaction can is cooled, and the target acrylic resin emulsion can be taken out.

  In the emulsion monomer dropping type emulsion polymerization method, for example, first, water, if necessary, PVA resin [I] and an auxiliary emulsifier are charged into the reaction vessel, and this is heated (usually 40 to 90 ° C.). , A water-soluble polymer having protective colloid ability other than PVA-based resin [I] and / or PVA-based resin [I], a part of a monomer component emulsified and dispersed with an auxiliary emulsifier and water as necessary A polymerization initiator is added to the reaction vessel to carry out initial polymerization. Next, the remaining monomer components are added to the reaction can while dropping all at once, and the polymerization is allowed to proceed while further adding a polymerization initiator as necessary. When it is determined that the polymerization reaction is completed, the reaction can is cooled, and the target acrylic resin emulsion can be taken out.

  Alternatively, the initial polymerization may be performed without adding the total amount of the monomer components and the polymerization initiator to the reaction can while dropping. In addition, when the reaction temperature is less than 70 ° C., it is preferable that a redox polymerization reaction system using a reducing agent is used because the reaction proceeds smoothly.

  In the present invention, the acrylic resin emulsion obtained by emulsion polymerization is typically milky white, and the average particle size of the acrylic resin (A) in the acrylic resin emulsion is 0.2 to 2 μm. It is preferable that the thickness is 0.3 to 1.5 μm.

  Here, the average particle diameter can be measured by a conventional method, for example, a laser analysis / scattering particle size distribution measuring apparatus “LA-950S2” (manufactured by Horiba, Ltd.).

The acrylic resin (A) in the acrylic resin emulsion has a glass transition temperature of −80 to 0 ° C.
When the glass transition temperature is too high, the acrylic resin becomes hard and becomes brittle when it dries, so that the re-hairing performance tends to be lowered.
Further, the lower the glass transition temperature, the better the hair styling property tends to be because the polymer becomes sticky, but the lower limit is −80 ° C., preferably −70 ° C.
In addition, the one where the content ratio of PVA-type resin [I] is large, the one where the glass transition temperature of acrylic resin (A) is low is preferable at the point of re-styling.

  The glass transition temperature of the acrylic resin (A) in the present invention is a value obtained by calculating the glass transition temperature of a homopolymer composed of each polymerization component constituting the acrylic resin by the Fox equation. It can adjust by adjusting suitably the weight ratio of each polymerization component which comprises A). In addition, when using together a functional group containing monomer, it may be calculated by the formula of Fox based on the main monomer component except this functional group containing monomer.

  Furthermore, in the present invention, at least a part of the PVA-based resin [I] is grafted to the acrylic resin (A). This is preferable from the viewpoint of reducing variations in measured values in intensity measurement.

  When the PVA resin [I] is grafted to the acrylic resin (A), the value (W) represented by the following formula (2) is preferably 90% by weight or less, more preferably 85% by weight. Or less, more preferably 80% by weight or less. In addition, as a minimum, it is 1 weight% normally, Preferably it is 5 weight%, More preferably, it is 10 weight%. This value is a measure of the degree of grafting, and if this value is too low, the degree of grafting is low, the protective colloid action during emulsion polymerization is reduced, and the polymerization stability tends to decrease. If it is too high, it tends to be difficult to form a stable emulsion at a high concentration.

The value (W) of equation (2) is calculated as follows.
That is, a target emulsion or the like is dried at room temperature to prepare a film, and the film is extracted in boiling water and acetone for 8 hours, respectively, to remove ungrafted resin and the like. In this case, the absolute dry weight of the film before extraction is w ₁ (g), and the absolute dry weight of the film after extraction is w ₂ (g), which is obtained from the following formula (2).

W (% by weight) = (w ₂ ) / (w ₁ ) × 100 (2)

  As a method of adjusting the value (W) of the above formula (2), the emulsion polymerization temperature may be changed (higher (W) is higher, lower (W) is lower), or excessively used as a polymerization catalyst. Examples thereof include a method in which a very small amount of reducing agent (for example, acidic sodium sulfite) is used in combination with sulfate or the like ((W) increases).

  In this invention, you may further add various additives to the acrylic resin emulsion after emulsion polymerization as needed. Examples of such additives include organic pigments, inorganic pigments, water-soluble additives, pH adjusters, preservatives, and antioxidants.

Thus, the acrylic resin emulsion of the present invention is obtained, and when used, it is preferably adjusted to 0.1 to 65% by weight as the non-volatile content.
Moreover, when using such an acrylic resin emulsion as a hair styling agent, when used in combination with other compounding components (resin and additives described later), the non-volatile content is usually 30 to 60% by weight. This is preferable in that the use of the resin and additives is not easily restricted.
In addition, when using this acrylic resin emulsion independently as a hairdressing agent, it is preferable that a non volatile matter shall be 1 to 10 weight% normally at the point which is easy to apply | coat uniformly with respect to hair.

  Thus, the acrylic resin emulsion of the present invention is obtained. Such an acrylic resin emulsion is used for hairdressing agents, and hairdressing agents using the emulsion exhibit desired performance.

  The hairdressing agent of the present invention may be one using an acrylic resin emulsion alone, or may be a combination of an acrylic resin emulsion and various compounding agents.

  In the hair styling agent of the present invention, the acrylic resin emulsion for hair styling agent of the present invention preferably contains 1% by weight or more (in terms of solid content) in the hair styling agent, more preferably 3% by weight or more (in terms of solid content). Yes, more preferably 5% by weight or more (in terms of solid content). In addition, as an upper limit, it is 70 weight% (solid content conversion) normally, Preferably it is 60 weight% (solid content conversion), More preferably, it is 50 weight% (solid content conversion). If the amount of the acrylic resin emulsion for hairdressing agent of the present invention is too small, the hairstyling power tends to decrease, and if it is too large, the cleaning property tends to decrease.

  In the hair styling agent of the present invention, various blending components used in known general hair styling agents such as oils, polyhydric alcohols, lower alcohols, surfactants, ultraviolet absorbers, fragrances, antioxidants are added to the acrylic resin emulsion. An agent, a moisturizer, a refreshing agent, vitamins, a plant extract and the like can be appropriately blended according to the purpose.

  Examples of the oil include sunflower oil, cottonseed oil, soybean oil, olive oil, coconut oil, castor oil, jojoba oil, camellia oil, mink oil and the like; beeswax, carnauba wax, candelilla wax, rice bran wax, shellac wax, whale wax, lanolin Waxes such as ceresin, paraffin wax, liquid paraffin, liquid isoparaffin, microcrystalline wax, polyethylene powder, polyethylene wax, Fischer-Tropsch wax, petrolatum, squalane, etc .; lauric acid, myristic acid, palmitic acid, stearin Higher fatty acids such as acid, oleic acid, behenic acid, 2-ethylbutanoic acid, isopentanoic acid, 2-methylpentanoic acid, 2-ethylpentanoic acid, isostearic acid, 12-hydroxystearic acid; lauryl alcohol, milli Higher alcohols such as til alcohol, cetyl alcohol, stearyl alcohol, oleyl alcohol, lanolin alcohol, behenyl alcohol, cetostearyl alcohol; ethyl oleate, isopropyl myristate, isopropyl palmitate, myristyl myristate, cetyl palmitate, oleyl oleate, myristine Octyl dodecyl oleate, octyl dodecyl oleate, ethyl isostearate, isopropyl isostearate, cetyl 2-ethylhexanoate, cetostearyl 2-ethylhexanoate, glyceryl tri-2-ethylhexanoate, glyceryl triisopalmitate, tetra-2-ethyl Pentaerythritol hexanoate, isocetyl octoate, isostearyl octoate, isocetyl isostearate, Fatty acid ester oils such as octyldodecyl stearate and octyldodecyl dimethyloctanoate; methylpolysiloxane, highly polymerized methylpolysiloxane, methylphenylpolysiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, octamethylcyclotetrasiloxane, decamethylcyclo Examples thereof include silicone oils such as pentasiloxane, dodecamethylcyclohexasiloxane, methylcyclopolysiloxane, alcohol-modified silicone, alkyl-modified silicone, amino-modified silicone, and epoxy-modified silicone. These may be used alone or in combination of two or more.

  The content of such an oil is usually preferably 0.5 to 50% by weight, particularly preferably 1 to 40% by weight in the total amount of the hairdressing agent from the viewpoint of emulsification. In addition, from the viewpoint of reducing the oiliness and stickiness of hairdressing materials, it is preferable to make the content as small as possible, but by using the acrylic resin emulsion of the present invention, the amount of oil used is reduced or not used. can do.

  Examples of the polyhydric alcohol include ethylene glycol, dipropylene glycol, propylene glycol, isoprene glycol, glycerin, diglycerin, 1,3-butylene glycol, 1,2-pentanediol, 1,2-hexanediol, 1, Examples include 2-octanediol and 1,2-decanediol. These may be used alone or in combination of two or more.

  The content of the polyhydric alcohol is preferably 0.1 to 20% by weight, particularly preferably 0.5 to 15% by weight, based on the feeling of use, in the total amount of the hairdressing agent.

  The acrylic resin emulsion for hairdressing agent of the present invention is used, for example, by diluting the acrylic resin emulsion with water, polyhydric alcohol, lower alcohol or the like as a liquid type hairdressing agent, or in the acrylic resin emulsion, Can be used as a viscous liquid type or cream type hair styling agent.

  For example, hair styling containing the acrylic resin emulsion for hair styling of the present invention can be performed as follows. The acrylic resin emulsion for hairdressing agent of the present invention containing the acrylic resin (A) dispersed and stabilized by the polyvinyl alcohol resin [I] is applied to the hair for an effective amount of hairstyling, and the acrylic resin for hairstyling agent is applied. During or before the application of the emulsion, the hair is trimmed to the desired shape. By styling in this way, a desired hairstyle can be easily formed.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the examples, “parts” and “%” mean weight basis.

  First, various acrylic resin emulsions were prepared as follows. The nonvolatile content and viscosity of the acrylic resin emulsion were measured according to the following method, and the glass transition temperature was measured according to the method described above.

<Nonvolatile content>
1 g of a sample is spread on a container of an aluminum foil dish formed to have the same bottom area as a flat weighing bottle 50 mm × 30 mm defined in JIS R 3503 (1994), and accurately weighed. Place the container in the center of the thermostatic bath, dry at 105 ° C. ± 2 ° C. for 60 ± 5 minutes, then allow to cool in a desiccator and weigh it.
And it computed by the following formula.
N = (Wd / Ws) × 100
(Here, N is the nonvolatile content (%), Wd is the weight (g) of the sample after drying, and Ws is the weight (g) of the sample before drying.)

<Viscosity>
It is measured with a Brookfield viscometer (for example, a BL type viscometer manufactured by Tokyo Keiki Co., Ltd.). About 500 ml of the sample is put in the sample container so that bubbles do not enter, and the sample container is held so that the liquid level of the sample is lower than the liquid level of the heat transfer medium in the thermostatic bath. Stir with a glass rod if necessary and measure at a sample temperature of 23 ± 1 ° C.
The viscosity was calculated by the following formula (2 significant digits).
η = Kn × θ
(Where η is the viscosity (mPa · s), Kn is the conversion multiplier attached to the viscometer, and θ is the average of the viscometer readings of two measurements).

<Example 1: Production of acrylic resin emulsion (1)>
A PUS resin (average saponification degree 99 mol%, average polymerization degree) containing 1,2-diol structural unit in the side chain in deionized water (92 parts) in a SUS reaction can provided with a cooling pipe and a stirring blade 300, the content of 1,2-diol structural unit in the side chain is 8 mol% / manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), 10 parts, sodium hydrogen sulfite 0.2 part, and sodium carbonate. And heated to 75 ° C.
77 parts of deionized water, 5 parts of unmodified PVA resin (manufactured by Nippon Synthetic Chemical Industry Co., Ltd .; trade name “GOHSENOL GL05”) and 100 parts of 2-ethylhexyl acrylate (i) and 10% APS ( 2.7 parts (ii) (ammonium persulfate) aqueous solution was prepared, and 10% of (i) and 30% of (ii) were first added to the reaction can and allowed to react for 45 minutes.
Next, the remaining 90% of (i) and 60% of (ii) were added dropwise over 3.5 hours and polymerized at 75 to 78 ° C.
After completion of the dropwise addition, 5% of (ii) was added and the temperature was maintained for 1.5 hours, and further 5% of (ii) was added and the temperature was maintained for 1.5 hours.
Thereafter, the mixture was cooled to obtain an acrylic resin emulsion (1) (nonvolatile content 46%; viscosity 125 mPa · s (B-type viscometer 12 rpm, 23 ° C.); glass transition temperature (Tg) of acrylic resin = −70 ° C.). . The acrylic resin emulsion (1) was dispersed and stabilized.

<Example 2: Production of acrylic resin emulsion (2)>
In Example 1, 100 parts of 2-ethylhexyl acrylate was changed to 90 parts of 2-ethylhexyl acrylate and 10 parts of methyl methacrylate, and “Gosenol GL05” (trade name, Nippon Synthetic Chemical Industry Co., Ltd.) as an unmodified PVA resin. Manufactured by Nippon Synthetic Chemical Industry Co., Ltd .; Acrylic resin emulsion (2) (non-volatile content: 43%; viscosity: 160 mPa · s (type B), except that the product name is “GOHSENOL EG05”. Viscometer 12 rpm, 23 ° C.); Glass transition temperature (Tg) = − 60 ° C. of acrylic resin was obtained. The acrylic resin emulsion (2) was dispersed and stabilized.

<Example 3: Production of acrylic resin emulsion (3)>
In Example 2, an acrylic resin emulsion was used in the same manner as in Example 2 except that 0.3 part of ethylene glycol dimethacrylate (manufactured by Mitsubishi Rayon Co., Ltd .; trade name “Acryester ED”) was added as an acrylic monomer. (3) (nonvolatile content 44%; viscosity 210 mPa · s (B-type viscometer 12 rpm, 23 ° C.); glass transition temperature (Tg) of acrylic resin = −60 ° C.) was obtained. The acrylic resin emulsion (3) was dispersed and stabilized.

<Example 4: Production of acrylic resin emulsion (4)>
In Example 1, 100 parts of 2-ethylhexyl acrylate was changed to 75 parts of 2-ethylhexyl acrylate and 25 parts of methyl methacrylate, and “GOHSENOL GL05” (trade name, Nippon Synthetic Chemical Industry Co., Ltd.) as an unmodified PVA resin. Manufactured by Nippon Synthetic Chemical Industry Co., Ltd .; Acrylic resin emulsion (4) (nonvolatile content: 46%; viscosity: 540 mPa · s (B type), except that the product name is changed to “GOHSENOL EG05”. Viscometer 12 rpm, 23 ° C.); Glass transition temperature (Tg) = − 43 ° C. of acrylic resin was obtained. The acrylic resin emulsion (4) was dispersed and stabilized.

<Example 5: Production of acrylic resin emulsion (5)>
In Example 4, an acrylic resin emulsion (5) (non-volatile content: 43%; viscosity; similar to Example 4) except that 0.2 part of acrylic ester ED (ethylene glycol dimethacrylate) was added as an acrylic monomer. 420 mPa · s (B-type viscometer 12 rpm, 23 ° C.); glass transition temperature (Tg) of acrylic resin (−43 ° C.) was obtained. The acrylic resin emulsion (5) was dispersed and stabilized.

<Example 6: Production of acrylic resin emulsion (6)>
In Example 1, 100 parts of 2-ethylhexyl acrylate was changed to 60 parts of 2-ethylhexyl acrylate and 40 parts of methyl methacrylate, and “Gosenol GL05” (trade name, Nippon Synthetic Chemical Industry Co., Ltd.) as an unmodified PVA resin. Manufactured by Nippon Synthetic Chemical Industry Co., Ltd .; acrylic resin emulsion (6) (non-volatile content: 44%; viscosity: 470 mPa · s (type B), except that the product name “GOHSENOL EG05” was changed. Viscometer 12 rpm, 23 ° C.); Glass transition temperature (Tg) of acrylic resin (−24 ° C.) was obtained. The acrylic resin emulsion (6) was dispersed and stabilized.

< Reference Example 1 : Production of acrylic resin emulsion (7)>
In a SUS reactor equipped with a cooling tube and a stirring blade, 92 parts of deionized water, 0.2 part of sodium bisulfite, and 0.4 part of sodium carbonate / water trihydrate were completely dissolved and heated to 75 ° C. .
PVA resin containing 77 parts of deionized water and 1,2-diol structural unit in the side chain in advance (average saponification degree 89 mol%, average polymerization degree 340, content of 1,2-diol bond in side chain 3 Mol% / manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 4 parts, 55 parts of n-butyl acrylate and 45 parts of methyl methacrylate (i) and 2.7 parts of 10% APS aqueous solution (ii) were prepared. First, 10% of (i) and 30% of (ii) were added to the reaction can and allowed to react for 45 minutes. Next, the remaining 90% of (i) and 60% of (ii) were added dropwise over 3.5 hours and polymerized at 75 to 78 ° C. After completion of the dropwise addition, 5% of (ii) was added and the temperature was maintained for 1.5 hours, and further 5% of (ii) was added and the temperature was maintained for 1.5 hours.
Thereafter, the mixture was cooled to obtain an acrylic resin emulsion (7) (nonvolatile content: 45%; viscosity: 600 mPa · s (B-type viscometer: 12 rpm, 23 ° C.); glass transition temperature (Tg) of acrylic resin = 3 ° C.). The acrylic resin emulsion (7) was dispersed and stabilized.

< Reference Example 2 : Production of acrylic resin emulsion (8)>
In a reaction vessel made of SUS provided with a cooling tube and a stirring blade, 169 parts of deionized water and a PVA resin containing 1,2-diol structural unit in the side chain (average saponification degree 99 mol%, average polymerization degree 300, 7 parts of 1,2-diol bond in the side chain / manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), 0.2 part of sodium hydrogen sulfite and 0.4 part of sodium carbonate / sansui were completely dissolved. The temperature was raised to 75 ° C. Prepare a mixture (i) of 54.7 parts of n-butyl acrylate, 44.8 parts of methyl methacrylate and 0.5 part of 2-acetocetoxyethyl methacrylate and 2.7 parts (ii) of 10% APS aqueous solution. Then, 100% of (i) and 90% of (ii) were dropped into the reaction can over 4.5 hours and polymerized at 75 to 78 ° C. After completion of the dropwise addition, 5% of (ii) was added and the temperature was maintained for 1.5 hours, and further 5% of (ii) was added and the temperature was maintained for 1.5 hours.
Thereafter, the mixture was cooled to obtain an acrylic resin emulsion (8) (nonvolatile content: 45%; viscosity: 500 mPa · s (B-type viscometer: 12 rpm, 23 ° C.); glass transition temperature (Tg) of acrylic resin = 9 ° C.). The acrylic resin emulsion (8) was dispersed and stabilized.

<Example 7 : Production of acrylic resin emulsion (9)>
In Example 4, an acrylic resin emulsion (9) (non-volatile content: 44%; 44%; except that 0.05 part of KBM503 (γ-methacryloxypropyltrimethoxysilane) was added as a monomer component. Viscosity 550 mPa · s (B-type viscometer 12 rpm, 23 ° C.); glass transition temperature (Tg) of acrylic resin (−43 ° C.) was obtained. The acrylic resin emulsion (9) was dispersed and stabilized.

<Example 8 : Production of acrylic resin emulsion (10)>
To 100 parts of the acrylic resin emulsion (1) obtained in Example 1, 10 parts of a 20% aqueous solution of an unmodified PVA resin (manufactured by Nippon Synthetic Chemical Industry Co., Ltd .; trade name “GOHSENOL GL05”) was added. Acrylic resin emulsion (10) (non-volatile content 44%; viscosity 140 mPa · s (B-type viscometer 12 rpm, 23 ° C.); acrylic resin glass transition temperature (Tg) = − 70 ° C.) was obtained. The acrylic resin emulsion (10) was dispersed and stabilized.

<Comparative Example 1>
PVA resin containing 1,2-diol structural unit in the side chain (average saponification degree 99 mol%, average polymerization degree 300, content of 1,2-diol bond in the side chain 8 mol% / Nippon GOHSEI Co., Ltd.) was diluted with deionized water to produce a 45% nonvolatile content and 3% PVA resin solution. The state of the PVA resin solution of Comparative Example 1 was dispersed and stabilized.

<Comparative Example 2>
An acrylic resin emulsion produced by emulsion polymerization using only an anionic surfactant (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name “Cooponyl WU-6406”; nonvolatile content 56%; viscosity 1200 mPa · s; acrylic The glass transition temperature of the resin was -68 ° C.) was diluted with deionized water to produce an acrylic resin emulsion having a nonvolatile content of 45% and 3%. The state of the acrylic resin emulsion of Comparative Example 2 was dispersed and stabilized.

<Manufacture of hairdressing agent test solution (A)>
For Examples 1 to 8 and Reference Examples 1 and 2 , the acrylic resin emulsions (1) to (10) were diluted with deionized water so that the non-volatile content would be 3%, respectively, and the hair styling test Solution (A) was obtained.
About the said Comparative Examples 1 and 2, the non-volatile content 3% was used and it was set as the hair-styling agent test solution (A).

  Using the hair styling agent test solution (A), hair styling performance (setting power), re-hair styling performance (re-setting power) and tactile sensation were evaluated as follows.

<Hair styling performance (setting power)>
Apply 0.5g of the above-mentioned hairdressing agent test solution (A) uniformly to the hair bundle (length 20cm x weight 1.2g; hair bundle shop) with a dropper and apply it more evenly with a finger wearing vinyl gloves. Applied. After adjusting with a finger so that the width of the bundle is about 1 cm and drying it with a blow dryer at 100 ° C. for 1 minute, turn the bundling side down with the tip of the hair at an angle of about 45 ° from directly above. And sensory evaluation was performed to determine whether the hair bundle was fixed. The evaluation method is as follows.
(Evaluation criteria)
○… The hair is shaped even after being shaken a little. △… Slightly spread the hair tip a little. ×… The hair ends are loose or slightly shaken. In the above evaluation, “○” indicates performance. Excellent, “Δ” is practically acceptable. In addition, “x” is inferior in performance.

<Re-styling performance (re-setting power)>
The hair bundle after performing the hair styling evaluation was loosened with a finger, and further spread with a comb, and then the hair bundle state when the hair bundle was made again with the finger was subjected to sensory evaluation. The evaluation method is as follows.
(Evaluation criteria)
○… The hair bundles are gathered again (hairs are adjusted)
Δ: The hair bundles are slightly spread, but the hair bundles are slightly spread. ×: The hair bundles are not formed and the hair is not trimmed. In the above evaluation, “◯” indicates excellent performance, and “Δ” is practically acceptable. In addition, “x” is inferior in performance.

<Tactile feel>
The feeling of touch with the fingers was evaluated for the feeling of unity of the hair at the time of the above-mentioned hair styling performance evaluation. The evaluation method is as follows.
(Evaluation criteria)
○: Moist and smooth Δ: Slightly crumbly X: Quite crumbly In the above evaluation, “◯” indicates excellent performance, and “Δ” is practically acceptable. In addition, “x” is inferior in performance.

<Manufacture of hairdressing agent test solution (B)>
For Examples 1 to 8 and Reference Examples 1 to 2 , acrylic resin emulsions (1) to (10) were used as they were, and for Comparative Examples 1 and 2, those having a nonvolatile content of 45% were used. Each was used as a hair styling test solution (B).

<Washable performance>
The hair styling agent test solution (B) was applied to a 50 μm thick PET (polyethylene terephthalate) film with a 40 μm applicator and dried at 100 ° C. for 5 minutes to obtain a coating film having a thickness of about 15 μm (when dried). Put a drop of deionized water on the coating film with a dropper and gently rub it 10 times (10 laps) with a finger to draw a circle with a diameter of about 1 cm. Pulp waste (Nippon Paper Crecia Co., Ltd., “Kimwipe” The degree of cleaning of the hairdressing agent solution on the coating film after wiping with “(registered trademark)” was visually evaluated. The evaluation method is as follows.
(Evaluation criteria)
○… 70% to 100% wiped △… 20% to less than 70% wiped ×… 0 to less than 20% wiped In the above evaluation, “○” indicates excellent performance, and “△” indicates practical use. Top allowed. In addition, “x” is inferior in performance.

From Examples 1 to 8 above, the hair styling agent using the acrylic resin emulsion dispersed and stabilized by the PVA resin of the present invention has a balance between styling performance (hair styling performance, re-styling performance, and tactile sensation) and washing performance. It turns out that it is excellent.

On the other hand, in Comparative Example 1 using PVA-based resin as an aqueous solution, it is found that the hair styling performance and the performance to be washed are good, but the hair styling property and tactile feel are poor.
Moreover, in Comparative Example 2 using an acrylic resin emulsion obtained using a non-PVA surfactant, although the hair styling performance, re-hair styling performance, and touch are good, the performance to be washed is poor, It turns out that it is a practically troublesome level as a hairdressing agent.

  The acrylic resin emulsion for hairdressing agents of the present invention has a well-balanced balance between styling performance (hairstyling performance, re-styling performance, and tactile sensation) and performance to be washed, so various compounding agents can be used in combination and applied to various dosage forms. Is a useful thing that can be.

Claims (4)

Containing acrylic resin (A) dispersed and stabilized by polyvinyl alcohol resin [I],
The polyvinyl alcohol-based resin [I] is a polyvinyl alcohol-based resin containing a side chain 1,2-diol structural unit represented by the following general formula (1):
The acrylic resin (A) is obtained by polymerizing a monomer component containing 40% by weight or more of an aliphatic (meth) acrylate monomer having 4 to 12 carbon atoms in the alkyl group. A glass transition temperature of the resin (A) is −80 to 0 ° C., and an acrylic resin emulsion for hairdressing agents.

(In Formula (1), R < ¹ > -R < ⁶ > represents a hydrogen atom or an organic group each independently, and X shows a single bond or a bond chain.) The content of the side chain 1,2-diol structural unit in the polyvinyl alcohol-based resin [I] containing the side chain 1,2-diol structural unit represented by the formula (1) is 1 to 15 mol%. The acrylic resin emulsion for hairdressing agents according to claim 1 . A hair styling agent comprising the acrylic resin emulsion for hair styling agent according to claim 1 or 2 . A step of applying to the hair an acrylic resin emulsion for hair styling agent having an effective hair styling amount according to claim 1 or 2 ;
A step of preparing hair into a desired shape during or before or after application of the acrylic resin emulsion for hairdressing agent,
A hair styling method comprising: