JP6635248B2 - 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 as a hair styling agent (hair styling agent), and more particularly, it has excellent water-solubility and / or re-dispersibility in water. The present invention relates to an acrylic resin emulsion having an excellent balance with performance.

There are various types of hair styling agents such as liquid, gel, foam, mist, cream, and wax.
Usually, a hair styling agent is mainly composed of a polymer (setting polymer) for maintaining a desired shape by forming a film on the hair surface, and further according to additives and dosage forms provided for various purposes. A polymer composition containing a solvent, a base, and the like to be compounded. In recent years, hair styling agents can be freely arranged at the time of hair styling, and hair creams and hair waxes, which are emulsifying agents using oils and water, have become mainstream as formulations that can be easily modified even after hair styling. I have.

  In addition, the hair styling agent is required to provide a desired shape to the hair and retain it for a long period of time, as well as styling (hair styling) such as excellent appearance performance and excellent tactile performance. In addition, simplicity in washing and removing the hair styling agent from hair after use is also required as a performance, and various hair styling agents have been developed.

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

JP 2009-286724 A JP 2011-148721 A

The hairdressing agent of Patent Document 1 has a property that a polyvinyl alcohol-based resin having a specific structure has a good curl holding power under high humidity conditions, has a low stickiness, has a moisturizing power, and has little damage to hair. In addition, the hairdressing agent of Patent Document 2 mentioned above enhances aesthetics at the time of use by blending a polyvinyl alcohol-based resin in the emulsified composition, and does not impart unnatural shine to the hair after application. It has performance.
However, there is room for improvement in the hairdressing agent described in Patent Document 1 in that the goodness of hand combs (fingers), combs, brushes, and the like is insufficient, and in terms of hair re-dressing properties after the hair is broken once. What remained. Further, the hair styling agent described in Patent Document 2 has a large stickiness, and further improvement in use feeling is required.

Furthermore, hair styling agents in recent years are required to have good hair styling ability and re-styling performance, and furthermore, hair styling holding power for maintaining a hairstyle once set for a long time. On the other hand, a hairdressing agent having good hairdressing power as described above contains many oil components such as wax, so that it is often difficult to wash off, and may be strongly rubbed or washed twice with a shampoo or the like. And so on, which may cause scalp roughening and drying troubles. Further, there is a concern that scalp troubles such as dandruff, itching, and hair loss due to insufficient cleaning of the oil component may result.
Therefore, hair styling agents in recent years are required to have both good styling performance (hair styling properties) and good washability.

  In view of such problems, the present invention provides styling performance (hair styling performance (setting power), hair styling performance (resetting power, reset holding power)), tactile sensation, and cleaning with water or lukewarm water. It is an object of the present invention to provide an acrylic resin emulsion for a hair styling agent that is effectively used in a hair styling agent having excellent balance in performance.

  However, the present inventors have conducted intensive studies in view of such circumstances, and as a result, have found that an acrylic resin emulsion obtained by emulsion polymerization of at least two types of monomer compositions, at least one of which is a (meth) acrylate-based monomer. A difference in glass transition temperature between the two types of polymers when each of the monomer compositions is polymerized, is 30 ° C. or more, and a monomer composition having a higher glass transition temperature is replaced with a monomer having a lower glass transition temperature. A hair styling agent containing an acrylic resin emulsion obtained by emulsion polymerization in an amount equal to or less than the composition provides styling performance (hair styling performance (setting power), hair styling performance (resetting power), tactile sensation) and cleaning performance. The inventor has found that the present invention is excellent in a good balance, and has completed the present invention.

That is, the gist of the present invention is as follows.
[1] An acrylic resin emulsion for a hairdressing agent, comprising an emulsion polymer of the monomer composition [I] and an emulsion polymer of the monomer composition [II],
The acrylic resin particles in the acrylic resin emulsion are dispersion-stabilized by a polyvinyl alcohol-based resin,
An acrylic resin emulsion for a hairdressing agent, wherein the monomer composition [I] and the monomer composition [II] satisfy the following conditions (i) to (iii).
(I) At least one of the monomer composition [I] and the monomer composition [II] contains a (meth) acrylate-based monomer.
(Ii) The glass transition temperature (Tg2) of the emulsion polymer of the monomer composition [II] determined by the Fox equation is the glass transition temperature of the emulsion polymer of the monomer composition [I] determined by the Fox equation. (Tg1) 30 ° C. or higher than rather high, the glass transition temperature (Tg1) is at 0 ℃ or less, and the glass transition temperature (Tg2) is 30 ° C. or higher.
(Iii) The blending ratio (weight ratio) of the monomer composition [I] and the monomer composition [II] is 50:50 to 99: 1 as monomer composition [I]: monomer composition [II].
[ 2 ] The acrylic resin emulsion for a hairdressing agent according to [1], wherein the polyvinyl alcohol-based resin contains a side chain 1,2-diol structural unit represented by the following formula (1).

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

[ 3 ] Emulsion polymerization of the monomer composition [I] is performed first using only the monomer composition [I] and the monomer composition [II], and then the monomer composition [II] is added and the monomer composition [II] is added. The method for producing an acrylic resin emulsion for a hairdressing agent according to the above [1] or [2] , wherein the emulsion polymerization of the product [II] is performed.
[ 4 ] A hairdressing agent comprising the acrylic resin emulsion for a hairdressing agent according to [1] or [2] .
[ 5 ] A hairdressing method including the following step (A) and step (B).
(A) a step of applying the acrylic resin emulsion for a hairdressing agent according to the above [1] or [2] to an effective hairdressing amount and hair;
(B) a step of shaping the hair into a desired shape before, simultaneously with, and / or after the step (A) .

  The acrylic resin emulsion for a hairdressing agent of the present invention is excellent in water solubility and / or redispersibility in water, and the hairdressing agent containing the acrylic resin emulsion for a hairdressing agent has excellent washing performance. It also has an excellent effect on the balance with styling performance.

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

<Acrylic resin emulsion for hair styling>
The acrylic resin emulsion for a hairdressing agent of the present invention is an acrylic resin emulsion obtained by emulsion-polymerizing the monomer composition [I] and the monomer composition [II], wherein the monomer composition [I] and the monomer composition The product [II] satisfies the following conditions (i) to (iii).
(I) At least one of the monomer composition [I] and the monomer composition [II] contains a (meth) acrylate-based monomer.
(Ii) a glass having a glass transition temperature (Tg2) determined by the Fox equation of a polymer polymerized using the monomer composition [II], determined by the Fox equation of a polymer polymerized using the monomer composition [I]; 30 ° C. or higher than the transition temperature (Tg1).
(Iii) The blending ratio (weight ratio) of the monomer composition [I] and the monomer composition [II] is 50:50 to 99: 1 as monomer composition [I]: monomer composition [II].

  The acrylic resin emulsion for a hair styling agent may be an acrylic resin emulsion obtained by emulsion polymerization of only the monomer composition [I] and the monomer composition [II] in two steps, or may be another monomer composition. An acrylic resin emulsion obtained by emulsion polymerization in three or more stages may be used. When emulsion polymerization is carried out in three or more stages, the polymerization may be carried out before, after or during the emulsion polymerization of the monomer composition [I] and the monomer composition [II].

  Among these, an acrylic resin emulsion obtained by emulsion-polymerizing only the monomer composition [I] and the monomer composition [II] as a monomer component in two stages is preferable in that the operation procedure is simple. An acrylic resin emulsion obtained by subjecting only the monomer composition [I] and the monomer composition [II] to emulsion polymerization in two steps in this order is particularly preferable in terms of stable production. In addition to the monomer components, <other components> described below can be used as appropriate.

  In the present invention, it is necessary that at least one of the monomer composition [I] and the monomer composition [II] contains a (meth) acrylate-based monomer, but preferably the monomer composition [I] and the monomer composition It is preferred that both [II] contain a (meth) acrylate-based monomer, since unreacted substances tend to be reduced and the amount of residual monomers is reduced, that is, safety is increased and odor is reduced.

In the present invention, the glass transition temperature (Tg2) of the polymer polymerized using the monomer composition [II] is determined by the Fox equation of the polymer polymerized using the monomer composition [I]. It is necessary that the monomer composition [I] and the monomer composition [II] are adjusted so as to be 30 ° C. or more higher than the glass transition temperature (Tg1), and the glass transition temperature (Tg1) and the glass transition temperature ( The difference from Tg2) is preferably at least 40 ° C, particularly preferably at least 50 ° C, more preferably at least 60 ° C, particularly preferably at least 90 ° C.
If the difference between Tg2 and Tg1 is too small, the washability tends to decrease, which is not preferable. The upper limit of the difference between Tg2 and Tg1 is usually 300 ° C., preferably 200 ° C.

The above Tg1 and Tg2 are calculated based on the glass transition temperature of each homopolymer by the following Fox equation. The glass transition temperature of the homopolymer in the following Fox equation is determined by the monomer type of the homopolymer.
That is, the glass transition temperatures (Tga, Tgb,..., Tgn) of the homopolymers can be the values described in “Polymer Handbook, 3rd edition, John Wiley & Sons, Inc, 1989”, respectively, and are described in the literature. Regarding the homopolymer of the monomer species which has not been obtained, a homopolymer having an average molecular weight of 10,000 or more and less than 1,000,000 can be polymerized and confirmed by differential scanning calorimetry (DSC) or the like. The average molecular weight is a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

From the above, the glass transition temperature (Tg1 and Tg2) of the polymer can be determined from the monomer species and its weight fraction.
In some cases, the glass transition temperature (Tg) of the homopolymer cannot be measured for some monomers. In this case, when the content of the monomer is about 5% by weight or less, the effect on the polymer properties is small. Therefore, the monomer is not considered as a component in the Fox formula.

The above Tg1 is preferably 0 ° C or lower, particularly preferably -20 ° C or lower, and more preferably -30 ° C or lower.
If Tg1 is too high, the acrylic resin particles in the acrylic resin emulsion become too hard to obtain sufficient tackiness, and the hair re-shaping property tends to be reduced.
The lower limit of Tg1 is usually -80C, preferably -75C.

The above Tg2 is preferably 30 ° C. or higher, particularly preferably 40 ° C. or higher, more preferably 50 ° C. or higher, particularly preferably 60 ° C. or higher.
If the Tg2 is too low, the acrylic resin particles in the obtained acrylic resin emulsion will be too soft, and it will be difficult to obtain continuous hair styling performance. In addition, when Tg2 is high, the cohesive force of the obtained acrylic resin locally increases, so that the acrylic resin tends to be tacky and the hair re-shaping property tends to be good.
The upper limit of Tg2 is usually 230 ° C, preferably 150 ° C.

In the present invention, the blending ratio (weight ratio) of the monomer composition [I] and the monomer composition [II] may be 50:50 to 99: 1, ie, monomer composition [I]: monomer composition [II]. It is necessary, preferably 60:40 to 98: 2, particularly preferably 65:35 to 97: 3, and more preferably 70:30 to 95: 5.
If the amount of the monomer composition [II] is too large relative to the monomer composition [I], the polymerization stability tends to be low and the hair styling properties tend to be insufficient. If the amount is too small, the balance between the hair styling properties and the washability decreases. Tend to.

<Monomer composition [I]>
The monomer composition [I] will be specifically described.
Examples of the monomer composition [I] include a (meth) acrylic monomer (I-1) and a functional group-containing monomer (I-2). The monomer composition [I] may be composed of only one or two or more (meth) acrylic monomers (I-1) or may be composed of only one or two or more functional group-containing monomers (I-2). It may contain one or more (meth) acrylic monomers (I-1) and one or more functional group-containing monomers (I-2). In particular, it is preferable that the (meth) acrylic monomer (I-1) be the main component.

Examples of the (meth) acrylic monomer (I-1) include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, and t-butyl (meth). A) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, lauryl (meth) acrylate, octyl (meth) acrylate, stearyl (meth) acrylate and other aliphatic (meth) acrylate monomers; phenoxy (meth) Aromatic (meth) acrylate monomers such as acrylate; and trifluoroethyl (meth) acrylate. These can be used alone or in combination of two or more.
Among these, an aliphatic (meth) acrylate-based monomer having 1 to 18 carbon atoms in the alkyl group is preferable from the viewpoint of the feeling of hair bunching and re-shaping property, and particularly preferably 1 to 12 carbon atoms in the alkyl group. It is an aliphatic (meth) acrylate monomer, more preferably an aliphatic (meth) acrylate monomer having an alkyl group having 4 to 12 carbon atoms, particularly preferably n-butyl acrylate or 2-ethylhexyl acrylate. It is. Also, a combination of 2-ethylhexyl acrylate and methyl methacrylate or a combination of n-butyl acrylate and methyl methacrylate can be suitably used.

Examples of the functional group-containing monomer (I-2) include a monomer having two or more vinyl groups in a molecular structure, a glycidyl group-containing monomer, an allyl group-containing monomer, a hydrolyzable silyl group-containing monomer, and an acetoacetyl group-containing monomer. , A hydroxyl group-containing monomer and a carboxyl group-containing monomer.
Among these, it is preferable to use a monomer having two or more vinyl groups in the molecular structure or a hydrolyzable silyl group-containing monomer, from the viewpoint of improving washability without deteriorating hair styling properties.

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 Methylolpropane tri (meth) acrylate, allyl (meth) acrylate and the like can be mentioned.
Among them, 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, 6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and trimethylolpropane tri (meth) acrylate are included in the (meth) acrylic monomer (I-1) and the monomer composition [II]. It is preferable because it is excellent in copolymerizability with a (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, and tetraallyloxyethane, allyl glycidyl ether, allyl acetate And the like.

Examples of the hydrolyzable silyl group-containing monomer include vinyl silyl group-containing monomers such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, and vinylmethyldimethoxysilane; γ- (meth) (Meth) acryloxy-based such as acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, and γ- (meth) acryloxypropylmethyldiethoxysilane Silyl group-containing monomers are exemplified.
Among them, the (meth) acryloxy-based silyl group-containing monomer is excellent in copolymerizability with the (meth) acrylic-based monomer (I-1) and the (meth) acrylate-based monomer contained in the monomer composition [II]. Is preferred.

  Examples of the acetoacetyl group-containing monomer include vinyl acetoacetate, allyl acetoacetate, allyl diacetacetate, acetoacetoxyethyl (meth) acrylate, acetoacetoxyethylcrotonate, acetoacetoxypropyl (meth) acrylate, and acetoacetoxy. Propylcrotonate, 2-cyanoacetoacetoxyethyl (meth) acrylate, and the like.

  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 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 Acids and the like can be mentioned, and among these, acrylic acid and methacrylic acid are preferable from the viewpoint of protective colloidal action at the time of emulsion polymerization and washability.

The content ratio of the (meth) acrylic monomer (I-1) is preferably from 80 to 100% by weight, particularly preferably from 85 to 99.99% by weight, based on the whole monomer composition [I]. , More preferably 90 to 99.9% by weight.
If the content of the (meth) acrylic monomer (I-1) is too small, sufficient hair styling performance tends not to be exhibited. When two or more monomers are included as the (meth) acrylic monomer (I-1), the total content of these monomers is preferably within the above range.

The content ratio of the functional group-containing monomer (I-2) is preferably 0 to 20% by weight, particularly preferably 0.01 to 15% by weight, and more preferably 0.01 to 15% by weight, based on the whole monomer composition [I]. Preferably it is 0.1 to 10% by weight.
If the content is too large, the acrylic resin becomes too hard, and sufficient adhesive strength is not obtained, and the hair styling property tends to decrease. If the content is too small, the effect of washability tends to be hardly exhibited. When two or more monomers are contained as the functional group-containing monomer (I-2), the total content of these monomers is preferably within the above range.

  When the functional group-containing monomer (I-2) includes a monomer having two or more vinyl groups in the molecular structure, the content ratio of the monomer having two or more vinyl groups in the molecular structure is determined by the monomer composition [I] It is preferably 0.01 to 10% by weight, particularly preferably 0.05 to 5% by weight, and further preferably 0.1 to 3% by weight, based on the whole.

  Further, when the functional group-containing monomer (I-2) includes a hydrolyzed silyl group-containing monomer, the content ratio of the hydrolyzed silyl group-containing monomer is 0.01 to 0.01 with respect to the entire monomer composition [I]. It is preferably 5% by weight, particularly preferably 0.02 to 3% by weight, more preferably 0.05 to 2% by weight.

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

<Monomer composition [II]>
The monomer composition [II] will be specifically described.
Examples of the monomer composition [II] include a (meth) acrylic monomer (II-1) and a functional group-containing monomer (II-2). The monomer composition [II] may be composed of only one or two or more (meth) acrylic monomers (II-1) or may be composed of only one or two or more functional group-containing monomers (II-2). It may contain one or more (meth) acrylic monomers (II-1) and one or more functional group-containing monomers (II-2). Especially, it is preferable to use a (meth) acrylic monomer (II-1) as a main component.

As the (meth) acrylic monomer (II-1), for example, as in the (meth) acrylic monomer (I-1), for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) A) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, lauryl (meth) acrylate, octyl (meth) acrylate, stearyl (meth) acrylate And the like. Aliphatic (meth) acrylate monomers such as phenoxy (meth) acrylate; and trifluoroethyl (meth) acrylate. These can be used alone or in combination of two or more.
Among these, an aliphatic (meth) acrylate-based monomer having 1 to 18 carbon atoms in the alkyl group is preferable from the viewpoint of the feeling of hair bunching and re-shaping property, and particularly preferably 1 to 12 carbon atoms in the alkyl group. It is an aliphatic (meth) acrylate monomer, more preferably an aliphatic (meth) acrylate monomer having an alkyl group having 1 to 4 carbon atoms, particularly preferably methyl methacrylate, ethyl methacrylate, propyl methacrylate, It is n-butyl methacrylate.
It is also possible to suitably use a combination of another (meth) acrylate with methyl methacrylate as a main component.

Examples of the functional group-containing monomer (II-2) include, as in the case of the functional group-containing monomer (I-2), a monomer having two or more vinyl groups in its molecular structure, a glycidyl group-containing monomer, and an allyl group-containing monomer. , A hydrolyzable silyl group-containing monomer, an acetoacetyl group-containing monomer, a hydroxyl group-containing monomer, and a carboxyl group-containing monomer.
Among these, it is preferable to copolymerize a monomer having two or more vinyl groups in the molecular structure or a monomer containing a hydrolyzable silyl group from the viewpoint of improving washability without deteriorating hair styling properties.

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 Methylolpropane tri (meth) acrylate, allyl (meth) acrylate and the like can be mentioned.
Among them, 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, 6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and trimethylolpropane tri (meth) acrylate are included in the (meth) acrylic monomer (II-1) and the monomer composition [I]. It is preferable because it is excellent in copolymerizability with a (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, and tetraallyloxyethane, allyl glycidyl ether, allyl acetate And the like.

Examples of the hydrolyzable silyl group-containing monomer include vinyl silyl group-containing monomers such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, and vinylmethyldimethoxysilane; γ- (meth) (Meth) acryloxy-based such as acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, and γ- (meth) acryloxypropylmethyldiethoxysilane Silyl group-containing monomers are exemplified.
Among them, the (meth) acryloxy-based silyl group-containing monomer is excellent in copolymerizability with the (meth) acrylic-based monomer (II-1) and the (meth) acrylate-based monomer contained in the monomer composition [I]. Is preferred.

  Examples of the acetoacetyl group-containing monomer include vinyl acetoacetate, allyl acetoacetate, allyl diacetacetate, acetoacetoxyethyl (meth) acrylate, acetoacetoxyethylcrotonate, acetoacetoxypropyl (meth) acrylate, and acetoacetoxy. Propylcrotonate, 2-cyanoacetoacetoxyethyl (meth) acrylate, and the like.

  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 viewpoints of colloidal action and 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 Acids and the like can be mentioned, and among these, acrylic acid and methacrylic acid are preferable from the viewpoint of protective colloidal action at the time of emulsion polymerization and washability.

The content ratio of the (meth) acrylic monomer (II-1) is preferably from 80 to 100% by weight, particularly preferably from 85 to 99.99% by weight, based on the whole monomer composition [II]. , More preferably 90 to 99.9% by weight.
When the content of the (meth) acrylic monomer (II-1) is at the above lower limit, sufficient hair styling performance tends to be exhibited. When two or more monomers are contained as the (meth) acrylic monomer (II-1), the total content of these monomers is preferably within the above range.

The content of the functional group-containing monomer (II-2) is preferably 0 to 20% by weight, particularly preferably 0.01 to 15% by weight, and more preferably 0.01 to 15% by weight, based on the whole monomer composition [II]. Preferably it is 0.1 to 10% by weight.
If the content is too large, the polymerization stability tends to decrease, and if the content is too small, the effect of the washability tends to be difficult to understand. When two or more monomers are contained as the functional group-containing monomer (II-2), the total content of these monomers is preferably within the above range.

  When the functional group-containing monomer (II-2) contains a monomer having two or more vinyl groups in the molecular structure, the content ratio of the monomer having two or more vinyl groups in the molecular structure is determined by the monomer composition [II] The content is preferably 0.01 to 10% by weight, particularly preferably 0.05 to 5% by weight, and further preferably 0.1 to 3% by weight, based on the whole.

  Further, when the functional group-containing monomer (II-2) contains a hydrolyzed silyl group-containing monomer, the content ratio of the hydrolyzed silyl group-containing monomer is from 0.01 to 0.01 with respect to the entire monomer composition [II]. It is preferably 5% by weight, particularly preferably 0.02 to 3% by weight, more preferably 0.05 to 2% by weight.

  In addition, as long as the effects of the present invention are not impaired, a small amount of styrene-based monomers such as styrene and α-methylstyrene; vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, and pivalin Vinyl ester monomers such as vinyl acrylate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl versatate, and vinyl 2-ethylhexanoate may be used.

<Other ingredients>
In the acrylic resin emulsion according to the present invention, other than the above-mentioned monomer composition [I] and monomer composition [II], other components can be appropriately used as needed. Examples of such other components include, for example, an emulsifier, a polymerization initiator, a polymerization regulator, a plasticizer, and the like. Among them, it is preferable to use an emulsifier. Such an emulsifier is preferably a water-soluble polymer, particularly preferably a polyvinyl alcohol-based resin (hereinafter sometimes referred to as “PVA-based resin”).
Further, in the present invention, it is preferable that the acrylic resin particles in the acrylic resin emulsion are dispersion-stabilized by the polyvinyl alcohol-based resin in that the washability is good.
The above-mentioned dispersion-stabilized state refers to a dispersion state in which the emulsion does not settle and separate even at 23 ° C. for one month and keeps a uniform state.

  As the PVA-based resin, a PVA-based resin having the following specific average saponification degree and average polymerization degree is preferable.

The average degree of saponification of the PVA-based resin is preferably 70 to 99.9 mol%, particularly preferably 80 to 99.5 mol%, and further preferably 85 to 99 mol%.
If the average degree of saponification is too low, the polymerization does not easily progress stably, and even if the polymerization is completed, the storage stability of the emulsion tends to decrease.If the average saponification degree is too high, the emulsion stability decreases. The tendency is that the production of emulsions becomes difficult.

  In this specification, the average degree of saponification can be determined in accordance with the method for calculating the degree of saponification described in JIS K 6726 (1994).

The average degree of polymerization of the PVA resin is preferably from 50 to 3,000, more preferably from 100 to 2,000, further preferably from 200 to 1,000, and particularly preferably from 200 to 1,000. ~ 500.
If the average degree of polymerization is too low, the protective colloid ability at the time of emulsion polymerization is insufficient and the polymerization tends to be difficult to proceed stably.If it is too high, the viscosity increases during polymerization and the reaction system becomes unstable. Dispersion stability tends to decrease.

  In addition, in this specification, an average degree of polymerization can be calculated | required according to the calculation method of the average degree of polymerization described in JISK6726 (1994).

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

  As the modified PVA-based resin, for example, an anion-modified PVA-based resin modified with an anionic group including a carboxylic acid group, a sulfonic acid group, and a phosphate group; modified with a cationic group such as a quaternary ammonium group Cation-modified PVA-based resin; Modified PVA-based resin modified with various functional groups such as acetoacetyl group, diacetone acrylamide group, mercapto group, silanol group and the like; Contains 1,2-diol structural unit in side chain PVA-based resins and the like can be mentioned.

  As the above-mentioned PVA-based resin, a PVA-based resin containing a 1,2-diol structural unit in a side chain is preferable in terms of excellent dispersion stability when a (meth) acrylic monomer is polymerized, and particularly preferable. It is a PVA-based resin containing a 1,2-diol structural unit represented by the following formula (1).

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

In the above formula (1), R ^{1 to} R ⁶ each independently represent a hydrogen atom or an organic group. Preferably, R ^{1 to} R ⁶ are all hydrogen atoms, but may be an organic group as long as the resin properties are not significantly impaired. The organic group is not particularly limited, but is preferably an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group. If necessary, it may have a substituent such as a halogeno group, a hydroxyl group, an ester group, a carboxylic acid group, a sulfonic acid group and the like.

In the formula (1), X is a single bond or a bond chain, and is preferably a single bond in terms of set holding power, non-stickiness, familiarity with hair, and the like. The binding chain is not particularly limited, but may be any of hydrocarbons such as alkylene, alkenylene, alkynylene, phenylene, and naphthylene (these hydrocarbons may be substituted with halogens such as fluorine, chlorine, and bromine). _{other, -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 OR) -, - OAl (OR) O-, and the like. Here, R is each independently an arbitrary substituent, and is preferably a hydrogen atom or an alkyl group. M is a natural number. Among them, in view of such viscosity stability and heat resistance during production, an alkylene group having 6 or less carbon atoms or _-CH 2 OCH _2, - preferably, a methylene _group, -CH 2 OCH ₂ - is more preferable.

  The PVA-based resin containing the 1,2-diol structural unit represented by the formula (1) can be prepared by, for example, a method of (a) saponifying a copolymer of vinyl acetate and 3,4-diacetoxy-1-butene. (B) a method of saponifying and decarboxylating a copolymer of vinyl acetate and vinyl ethylene carbonate, (c) a copolymer of vinyl acetate and 2,2-dialkyl-4-vinyl-1,3-dioxolane And (d) a method of saponifying a copolymer of vinyl acetate and glycerin 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 from 1 to 15 mol%, particularly preferably from 1 to 15 mol%. 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 decrease. If the content is too high, the stability during polymerization decreases, and a stable emulsion having a high nonvolatile content is obtained. Tends to be difficult.

The content of the side chain 1,2-diol unit in the PVA-based resin is obtained from a ¹ H-NMR spectrum (solvent: DMSO-d ₆ , internal standard: tetramethylsilane) of completely saponified PVA. Specifically, it can be calculated from the peak area derived from a hydroxyl proton in a 1,2-diol unit, a methine proton, a methylene proton, a methylene proton in the main chain, or a proton in a hydroxyl group connected to the main chain. I just need.

The average saponification degree of the PVA-based 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 average degree of saponification is too small, the stability of the emulsion during polymerization tends to be low, and it tends to be difficult to obtain the desired emulsion.

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

  Further, the PVA-based resin 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, and is preferably water.

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

The amount of the PVA-based resin to be used is preferably 0.01 to 40 parts by weight, particularly preferably 0.1 to 40 parts by weight, based on 100 parts by weight in total of the monomer composition [I] and the monomer composition [II]. To 30 parts by weight, more preferably 0.5 to 20 parts by weight.
If the amount of the PVA-based resin is too small, the amount of protective colloid at the time of emulsion polymerization becomes insufficient, and the polymerization stability tends to decrease. If the amount is too large, an acrylic resin emulsion is used. Tends to increase and the stability tends to decrease.

  Examples of the emulsifier other than the PVA-based resin include an anionic, cationic, and nonionic surfactant, a water-soluble polymer having a protective colloid ability other than the PVA-based resin, and a water-soluble oligomer.

  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. In addition, a reactive surfactant having a radically polymerizable unsaturated bond in the structure can be used as the surfactant. These can be used alone or in combination of two or more.

  The use of the above-mentioned surfactant has an effect of making emulsion polymerization proceed smoothly and facilitating control (effect as an emulsifier) and suppressing the generation of coarse particles and block-like substances generated during polymerization. However, when many of these surfactants are used as an emulsifier, the graft ratio tends to decrease. Therefore, when a surfactant is used, it is desirable that the amount used is an auxiliary amount to the PVA-based resin, that is, it is desirable to use as little as possible.

  Examples of the water-soluble polymer having a protective colloid ability other than the PVA-based resin include hydroxyethylcellulose, polyvinylpyrrolidone, and methylcellulose. These may be used alone or in combination of two or more. These are effective in increasing the viscosity of the emulsion and changing the viscosity by changing the particle size of the emulsion.

  As the water-soluble oligomer, for example, a polymer having a hydrophilic group such as a sulfonic acid group, a carboxyl group, a hydroxyl group, and an alkylene glycol group is preferable, and a polymer or copolymer having a degree of polymerization of about 10 to 500 is preferable. It is listed. Specific examples of the water-soluble oligomer include, for example, amide-based copolymers such as 2-methacrylamide-2-methylpropanesulfonic acid copolymer, sodium methacrylate-4-styrenesulfonate copolymer, and styrene / maleic acid copolymer. Examples thereof include polymers, melaminesulfonic acid formaldehyde condensates, and poly (meth) acrylates. Further, specific examples include a monomer having a sulfonic acid group, a carboxyl group, a hydroxyl group, an alkylene glycol group and the like, and a water-soluble oligomer obtained by previously copolymerizing a radically polymerizable reactive emulsifier alone or with another monomer. Can be These may be used alone or in combination of two or more.

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

  The polymerization regulator can be appropriately selected from known ones. 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 and thiol. And mercaptans such as glycolic acid, octyl thioglycolate, and thioglycerol. These can be used alone or in combination of two or more. The use of the chain transfer agent is effective in stabilizing the polymerization, and is preferably used 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 can be used alone or in combination of two or more.

  As the plasticizer, an adipate-based plasticizer, a phthalate-based plasticizer, a phosphate-based plasticizer, or the like can be used.

  The amounts of these other components can be appropriately selected according to the purpose within a range that does not impair the effects of the present invention.

<Production method of acrylic resin emulsion>
A method for producing an acrylic resin emulsion obtained by subjecting the monomer composition [I] and the monomer composition [II] to emulsion polymerization in two steps in this order will be described.

  The acrylic resin emulsion of the present invention uses, for example, a PVA-based resin as a dispersion stabilizer, first obtains a first emulsion by emulsion polymerization of a monomer composition [I], and then obtains a monomer composition [II]. Is emulsion-polymerized in the first emulsion.

  Usually, the emulsion polymerization is carried out by using other components such as a polymerization initiator, a polymerization regulator, an auxiliary emulsifier and the like as required, in addition to the PVA-based resin and the monomer components. In addition, the reaction conditions for the polymerization can be appropriately selected according to the type and purpose of the monomer.

Examples of the emulsion polymerization method include, for example, a monomer dropping emulsion polymerization method in which water and a PVA-based resin are charged into a reaction vessel, and the temperature is raised to drop the monomer component and the polymerization initiator; An emulsion monomer drop-type emulsion polymerization method in which a mixed monomer is previously dispersed and emulsified with water and a water-soluble polymer having a protective colloid function other than PVA-based resin and / or PVA-based resin, and the dispersed / emulsified monomer is added dropwise. The emulsified monomer dropping polymerization method is advantageous in terms of reactivity when using a hydrophobic monomer, management and control of the polymerization step, and the like.
Further, in order to impart stability to the emulsion and impart water solubility and / or redispersibility to water, a PVA-based resin and / or a water-soluble polymer having a protective colloid other than the PVA-based resin at the end of the polymerization reaction is used. It is also possible to add later.

  The emulsion polymerization process will be described more specifically below.

  In the above-mentioned monomer drop-type emulsion polymerization, for example, first, water, a PVA-based resin, and, if necessary, an auxiliary emulsifier are charged into a reaction vessel, and after raising the temperature (normally 40 to 90 ° C), the monomer composition [I] (Usually 0.1 to 50% by weight, preferably 1 to 30% by weight, based on the total amount of the monomer composition [I]) and a polymerization initiator are added to the reaction vessel to carry out initial polymerization. . Next, the remaining monomer composition of the monomer composition [I] is added to the reaction vessel in a lump or dropwise, and the polymerization is allowed to proceed while further adding a polymerization initiator as needed. Next, the monomer composition [II] is added to the reaction vessel in a lump or dropwise, and the polymerization is allowed to proceed while further adding a polymerization initiator as needed. When it is determined that the polymerization reaction has been completed, the reaction vessel is cooled and the intended acrylic resin emulsion can be taken out.

  In addition, in the emulsion monomer dropping type emulsion polymerization method, for example, first, water, a PVA-based resin and an auxiliary emulsifier are charged in a reaction vessel, and the temperature is raised (normally 40 to 90 ° C.). A part of the monomer composition [I] emulsified and dispersed with a water-soluble polymer having a protective colloid function other than the resin and / or the PVA-based resin and, if necessary, an auxiliary emulsifier and water (the total amount of the monomer composition [I]) , Usually 0.1 to 50% by weight, preferably 1 to 30% by weight) and a polymerization initiator are added to the reaction vessel to carry out initial polymerization. Next, the remaining monomer composition of the monomer composition [I] is added to the reaction vessel in a lump or dropwise, and the polymerization is allowed to proceed while further adding a polymerization initiator as needed. Next, the PVA-based resin and / or a water-soluble polymer having a protective colloid function other than the PVA-based resin, and a monomer composition [II] emulsified and dispersed with an auxiliary emulsifier and water, if necessary, in a lump or while dropping. And the polymerization is allowed to proceed while further adding a polymerization initiator as needed. When it is determined that the polymerization reaction has been completed, the reaction vessel is cooled and the intended acrylic resin emulsion can be taken out.

  Further, the entire amount of the monomer composition [I] and the polymerization initiator were added dropwise to the reaction vessel without performing the initial polymerization, and then the reaction was performed while adding the entire amount of the monomer composition [II] and the polymerization initiator dropwise. It can also be carried out by adding it to a can. When the reaction temperature is lower than 70 ° C., it is preferable to use a redox polymerization reaction system using a reducing agent in combination, since the reaction proceeds smoothly.

  In the emulsion polymerization of the monomer composition [I], polymerization is usually continued for 5 minutes to 1 hour (preferably 10 minutes to 30 minutes) from the time when the addition of the entire amount of the monomer composition [I] is completed, and the monomer composition [I] When the polymerization rate of the compound (I) exceeds 90% (preferably 95%), the polymerization may be considered to be completed and the first emulsion may be obtained. If the emulsion polymerization of the monomer composition [II] is subsequently performed, Good.

  In the present invention, the acrylic resin emulsion obtained by emulsion polymerization is typically uniform milky white, and the average particle size of the acrylic resin in the acrylic resin emulsion is 0.2 to 2 μm. And more preferably 0.3 to 1.5 μm.

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

  Furthermore, in the present invention, at least a portion of the PVA-based resin is grafted to the acrylic resin, and the storage stability and measured value of the adhesive strength of the obtained acrylic resin emulsion before drying are measured. This is preferable in that variations are reduced.

  When the PVA-based resin is grafted on the acrylic resin, the value (W) represented by the following formula (2) is preferably 90% by weight or less, more preferably 85% by weight or less, and still more preferably Is 80% by weight or less. The lower limit is usually 1% by weight, preferably 5% by weight, more preferably 10% by weight. Such a value is a measure of the degree of grafting.If this value is too low, the degree of grafting is low, the protective colloid action during emulsion polymerization is reduced, and the tendency for polymerization stability to be reduced. If it is too high, it tends to be difficult to produce a stable emulsion at a high concentration.

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

  Examples of the method of adjusting the value (W) of the above formula (2) include a method of changing the emulsion polymerization temperature and a method of using a very small amount of a reducing agent in combination with a persulfate used as a polymerization catalyst. Can be For example, the value (W) can be increased by increasing the emulsion polymerization temperature, and the value (W) can be decreased by decreasing the emulsion polymerization temperature. When sodium acid sulfite or the like is used as the reducing agent, the value (W) increases.

  In the present invention, various additives may be further added to the acrylic resin emulsion after the emulsion polymerization, if necessary. Examples of such additives include organic pigments, inorganic pigments, water-soluble additives, pH adjusters, preservatives, and antioxidants.

In this way, the acrylic resin emulsion according to the present invention is obtained, and when it is used, it is usually preferable to adjust the nonvolatile content to 0.1 to 65% by weight.
When such an acrylic resin emulsion is used as a hairdressing agent, when other components such as resins and additives described later are used in combination, the non-volatile content is usually 30 to 60% by weight. This is preferable because the use of resins and additives is not easily restricted.
When such an acrylic resin emulsion is used alone as a hairdressing agent, it is preferable that the non-volatile content is usually 1 to 10% by weight in terms of easy application to hair.

  By the above method, the acrylic resin emulsion according to the present invention is obtained. Such an acrylic resin emulsion is used for a hairdressing agent, and a hairdressing agent using the emulsion exhibits desired performances such as styling properties, hair reshaping performance, tactile sensation, and washing performance.

  The hair styling agent according to the present invention may contain the above-mentioned acrylic resin emulsion, and may be one using the acrylic resin emulsion alone or a combination of the acrylic resin emulsion and various compounding agents. May be done.

  In the hair styling composition of the present invention, the acrylic resin emulsion for a hair styling composition of the present invention preferably contains 1% by weight or more (in terms of solid content), more preferably 3% by weight or more (in terms of solid content) of the hair styling composition. And more preferably at least 5% by weight (in terms of solid content). The upper limit is preferably 70% by weight (in terms of solids), more preferably 60% by weight (in terms of solids), and still more preferably 50% by weight (in terms of solids). If the amount of the acrylic resin emulsion for a hairdressing agent of the present invention is too small, the hairdressing power tends to decrease, and if it is too large, the washability tends to decrease.

  In the hairdressing composition of the present invention, the above-mentioned acrylic resin emulsion contains various compounding ingredients used in known general hairdressing compositions, such as oils, polyhydric alcohols, lower alcohols, surfactants, ultraviolet absorbers, fragrances, and antioxidants. It can be produced by appropriately blending agents, humectants, cooling agents, vitamins, plant extracts, and the like according to the purpose.

  Examples of the oils include oils such as sunflower oil, cottonseed oil, soybean oil, olive oil, coconut oil, castor oil, jojoba oil, camellia oil, mink oil; 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, hydrocarbon oils such as Fischer-Tropsch wax, petrolatum, squalane; 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 and 12-hydroxystearic acid; lauryl alcohol, milliliter Higher alcohols such as tyl alcohol, cetyl alcohol, stearyl alcohol, oleyl alcohol, lanolin alcohol, behenyl alcohol, and cetostearyl alcohol; ethyl oleate, isopropyl myristate, isopropyl palmitate, myristyl myristate, cetyl palmitate, oleyl oleate, myristine Octyldodecyl acrylate, octyldodecyl oleate, ethyl isostearate, isopropyl isostearate, cetyl 2-ethylhexanoate, cetostearyl 2-ethylhexanoate, glyceryl tri-2-ethylhexanoate, glyceryl triisopalmitate, tetra-2-ethyl Pentaerythritol hexanoate, isocetyl octanoate, isostearyl octanoate, isocetyl isostearate, Fatty acid ester oils such as octyldodecyl stearate and octyldodecyl dimethyloctanoate; methylpolysiloxane, highly polymerized methylpolysiloxane, methylphenylpolysiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, octamethylcyclotetrasiloxane, decamethylcyclo Examples 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.

  From the viewpoint of emulsification, the content of such an oil agent is usually preferably from 0.5 to 50% by weight, particularly preferably from 1 to 40% by weight, based on the total amount of the hairdressing agent. Further, from the viewpoint of reducing the oiliness and stickiness of the hair styling agent, it is preferable that the content is as small as possible.However, by using the acrylic resin emulsion of the present invention, the amount of the oil agent 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, Examples thereof include 2-octanediol and 1,2-decanediol. These may be used alone or in combination of two or more.

  From the viewpoint of feeling of use, 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 total amount of the hairdressing agent.

  The acrylic resin emulsion for a hairdressing agent of the present invention can be used, for example, by diluting the acrylic resin emulsion with water, a polyhydric alcohol, a lower alcohol, or the like, and using it as a liquid type hairdressing agent. Is emulsified and dispersed with a surfactant and water to be used as a viscous liquid type or cream type hair styling agent.

<Hairdressing method>
Examples of the hair styling method using the hair styling agent containing the acrylic resin emulsion for hair styling according to the present invention include a hair styling method including the following steps (A) and (B).
(A) a step of applying an acrylic resin emulsion for a hairdressing agent obtained by emulsion polymerization of the monomer composition [I] and the monomer composition [II] to an effective hairdressing amount and hair;
(B) a step of shaping the hair into a desired shape before, simultaneously with, and / or after the step (A).
However, the monomer composition [I] and the monomer composition [II] satisfy the following conditions (i) to (iii).
(I) At least one of the monomer composition [I] and the monomer composition [II] contains a (meth) acrylate-based monomer.
(Ii) The glass transition temperature (Tg2) of the polymer polymerized using the monomer composition [II] determined by the Fox equation is determined by the Fox equation of the polymer polymerized using the monomer composition [I]. 30 ° C. or higher than the glass transition temperature (Tg1).
(Iii) The blending ratio (weight ratio) of the monomer composition [I] and the monomer composition [II] is 50:50 to 99: 1 as monomer composition [I]: monomer composition [II].
By adjusting the hair in this manner, a desired hairstyle can be easily formed. The hair styling agent of the present invention is excellent in water solubility and / or re-dispersibility in water, so that it can be easily washed away.
The effective amount of hair of the acrylic resin emulsion for a hairdressing agent is preferably 0.01 to 1 g per hair bundle having a length of 20 cm and a weight of 1.2 g from the viewpoint that hair can be efficiently arranged.

  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 of the present invention. In the examples, “parts” and “%” mean on a weight basis.

  First, various acrylic resin emulsions were prepared as described below. The nonvolatile content and the viscosity of the acrylic resin emulsion were measured by the following methods, and the glass transition temperature was measured by the above-mentioned method.

<Nonvolatile content>
1 g of a sample was spread and spread on a container of an aluminum foil dish molded to the same bottom area as a 50 mm x 30 mm flat weighing bottle specified in JIS R 3503 (1994) and weighed accurately. The container was placed in the center of a thermostat, dried at 105 ° C. ± 2 ° C. for 60 ± 5 minutes, then allowed to cool in a desiccator and weighed.
Then, it was calculated by the following equation.
N = (Wd / Ws) × 100
(Where 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 was measured with a Brookfield viscometer (for example, BL viscometer manufactured by Tokyo Keiki Co., Ltd.). About 500 ml of the sample was placed in a sample container so that air bubbles did not enter the sample container, and the sample container was held such that the liquid level of the sample was lower than the liquid level of the heat transfer medium in the thermostatic bath. The mixture was stirred with a glass rod as necessary, and the measurement was performed at a sample temperature of 23 ± 1 ° C.
The viscosity was calculated by the following equation (two significant figures).
η = Kn × θ
(Here, 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: Acrylic resin emulsion (a)>
Using the following monomer composition [I] and monomer composition [II], the following emulsion X, emulsion Y and solution Z were prepared.
-Monomer composition [I]: 75 parts of 2-ethylhexyl acrylate, 16 parts of methyl methacrylate, 0.9 part of ethylene glycol dimethacrylate (manufactured by Mitsubishi Rayon Co., Ltd .; trade name "Acryester ED"), Tg1 = -52 ° C
-Monomer composition [II]: 9 parts of methyl methacrylate, 0.1 part of ethylene glycol dimethacrylate (manufactured by Mitsubishi Rayon Co., Ltd .; trade name "Acryester ED"), Tg2 = 105 ° C
Emulsion liquid X: 64 parts of deionized water, 4.5 parts of an unmodified PVA-based resin (average degree of saponification: 88 mol%, average degree of polymerization: 500 / manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), monomer composition [I] Emulsified at 1200 rpm for 20 minutes using turbine blades.
Emulsion Y: 7 parts of deionized water, 0.5 part of unmodified PVA-based resin (average degree of saponification: 88 mol%, average degree of polymerization: 500 / manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), and monomer composition [II] Emulsified at 1200 rpm for 20 minutes using turbine blades.
Solution Z: 2.7 parts of 10% APS (ammonium persulfate) aqueous solution

In a stainless steel (SUS) reaction vessel provided with a cooling pipe and a stirring blade, PVA containing 1,2-diol structural unit in a side chain in deionized water (72 parts) (average degree of saponification: 99 mol%, average Degree of polymerization 300, content of side chain 1,2-diol structural unit 8 mol% / manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 10 parts, sodium bisulfite 0.2 parts and sodium carbonate trihydrate 0.4 Was completely dissolved, and the temperature was raised to 75 ° C.
First, 11% of the emulsion X and 30% of the solution Z are added all at once to the reaction vessel and stirred for 45 minutes. Then, the remaining 89% of the emulsion X and 53% of the solution Z are added for 3.1 hours. After completion of the dropwise addition, stirring was continued for 10 minutes to obtain a first emulsion.
Next, the whole amount of the emulsion Y and 7% of the solution Z were added dropwise over 0.4 hours, 10 minutes after the completion of the addition, 5% of the solution Z was added all at once, and 35 minutes later, 5% of the solution Z was added all at once. Added and stirred for 45 minutes. During the polymerization, the polymerization was carried out such that the internal temperature of the polymerization solution was kept at 75 to 80 ° C. Then, the internal temperature was adjusted to 55 ° C., 1.7 parts of a 10% aqueous solution of perbutyl H-69 (manufactured by NOF CORPORATION) was added all at once, and 3.4 parts of a 5% aqueous solution of vitamin C were divided into two portions for 30 minutes. Every second, the mixture was stirred while keeping the internal temperature at 50 to 55 ° C. for a total of 1 hour to obtain a second emulsion.
The obtained second emulsion was cooled to obtain an acrylic resin emulsion (a) (43% non-volatile content; viscosity: 420 mPa · s (B-type viscometer: 12 rpm, 23 ° C.)). The dispersion of the acrylic resin emulsion (a) was stabilized.

<Example 2: Acrylic resin emulsion (b)>
In Example 1, 68 parts of 2-ethylhexyl acrylate, 23 parts of methyl methacrylate, 0.9 part of ethylene glycol dimethacrylate (manufactured by Mitsubishi Rayon Co., Ltd .; trade name "Acryester ED"), 0.9 part of Tg1 =- An acrylic resin emulsion (b) (43% non-volatile content; viscosity: 1000 mPa · s (B-type viscometer: 12 rpm, 23 ° C.)) was obtained in the same manner as in Example 1 except that the temperature was changed to 43 ° C. The acrylic resin emulsion (b) was dispersion-stabilized.

<Comparative Example 1: Acrylic resin emulsion (a ′)>
Emulsion X and solution Z shown below were prepared in advance using the following monomer composition [I].
-Monomer composition [I]: 75 parts of 2-ethylhexyl acrylate, 35 parts of methyl methacrylate, 1 part of ethylene glycol dimethacrylate (manufactured by Mitsubishi Rayon Co., Ltd .; trade name "Acryester ED"), Tg1 = -43 ° C
Emulsion X: 71 parts of deionized water, 5 parts of unmodified PVA-based resin (average degree of saponification 88 mol%, average degree of polymerization 500 / manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), and monomer composition [I] as turbine blades Emulsified at 1200 rpm for 20 minutes.
Solution Z: 2.7 parts of 10% APS (ammonium persulfate) aqueous solution

A PVA-based resin containing 1,2-diol structural unit in a side chain in deionized water (72 parts) (average degree of saponification: 99 mol%, average degree of polymerization: 300, 8 mol% of 1,2-diol structural unit in side chain / manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 10 parts, sodium hydrogen sulfite 0.2 part, and sodium carbonate trihydrate 0.4 part. Was completely dissolved, and the temperature was raised to 75 ° C.
First, 10% of the emulsion X and 30% of the solution Z are added all at once to the reaction vessel and stirred for 45 minutes. Then, the remaining 90% of the emulsion X and 60% of the solution Z are added for 3.5 hours. And polymerized in one step at an internal temperature of 75 to 80 ° C. Ten minutes after the completion of the dropwise addition, 5% of the solution Z was added all at once, and 35 minutes later, 5% of the solution Z was added all at once, followed by stirring for 45 minutes. During the polymerization, the polymerization was carried out such that the internal temperature of the polymerization solution was kept at 75 to 80 ° C. Then, the internal temperature was adjusted to 55 ° C., 1.7 parts of a 10% aqueous solution of perbutyl H-69 (manufactured by NOF CORPORATION) was added all at once, and 3.4 parts of a 5% aqueous solution of vitamin C were divided into two portions for 30 minutes. The mixture was stirred and added while maintaining the internal temperature at 50 to 55 ° C for a total of 1 hour.
Thereafter, the mixture was cooled to obtain an acrylic resin emulsion (a ′) (43% of non-volatile content; viscosity: 490 mPa · s (B-type viscometer: 12 rpm, 23 ° C.)). The acrylic resin emulsion (a ′) of Comparative Example 1 was dispersion-stabilized.

<Comparative Example 2: Acrylic resin emulsion (b ′)>
In Comparative Example 1, the monomer composition [I] was 68 parts of 2-ethylhexyl acrylate, 32 parts of methyl methacrylate, 1 part of ethylene glycol dimethacrylate (manufactured by Mitsubishi Rayon Co., Ltd .; trade name “Acryester ED”), Tg1 = −35 ° C. Acrylic resin emulsion (b ′) (43% non-volatile content; viscosity 810 mPa · s (B-type viscometer 12 rpm, 23 ° C.)) was obtained in the same manner as in Comparative Example 1 except that the above was changed. The acrylic resin emulsion (b ') of Comparative Example 2 was dispersion-stabilized.

<Production of hair styling solution for styling performance test>
In Examples 1 and 2, the acrylic resin emulsion (a) and the acrylic resin emulsion (b) were used, and in Comparative Examples 1 and 2, the acrylic resin emulsion (a ') and the acrylic resin emulsion ( Each of b ′) was diluted with deionized water so that the non-volatile content was 3%, to give hair styling solutions for styling performance tests.

  Using the above hair styling solution for styling performance test, hair styling performance (setting power), hair styling performance (resetting power, reset holding power), and tactile sensation were evaluated as described below.

<Hair styling performance (setting power)>
The hair styling solution for hair styling test (0.5 g) is evenly applied to a hair bundle (length 20 cm × weight 1.2 g; hair bunker) with a dropper, and then evenly blended with a finger wearing vinyl gloves. Applied. After adjusting the bundle with your finger so that the width is about 1 cm, and drying it with an air dryer at 100 ° C for 1 minute, turn the bundled part down and hand at an angle of about 45 ° from directly above. And carried out a sensory evaluation as to whether or not the hair bundle was fixed. The evaluation method is as follows.
(Evaluation criteria)
○: The hair is set even if it is shaken a little.
Δ: The hair tips spread slightly when shaken slightly.
×: Hairs are loose or loose when shaken slightly.

<Re-shaping performance (resetting ability)>
After the hair bundle having been subjected to the hair styling evaluation was loosened with a finger and separated with a comb, the state of the hair bundle when a hair bundle was formed again with a finger was organoleptically evaluated. The evaluation method is as follows.
(Evaluation criteria)
…: The hair bundle is re-assembled (hair is adjusted).
Δ: The hair bundle is slightly spread, though it is collected.
×: Hair is not adjusted because it does not become a hair bundle.
In the above evaluation, “○” indicates excellent performance, and “△” is practically acceptable. Moreover, "x" is inferior in performance.

<Re-shaping performance (reset holding power)>
After the hair re-formation performance (resetting force) evaluation was performed, the hair bundle state when the hair bundle was shaken lightly was subjected to a sensory evaluation. The evaluation method is as follows.
(Evaluation criteria)
…: The hair bundles are hardly collapsed while the hair bundles are united (rearrangement of hair is maintained).
Δ: The hair bundle spreads slightly.
X: The hair bundle is largely disintegrated (the reshaping is not maintained).

<Tactile properties>
The feeling of unity of the hair at the time of the evaluation of the hair restoring performance (resetting force) was evaluated by the feeling of touch with a finger. The evaluation method is as follows.
(Evaluation criteria)
○: It is moist and smooth.
△… Slightly crisp.
×: It's quite dry.

<Production of hair styling solution for washing performance test>
In Examples 1 and 2, the acrylic resin emulsion (a) and the acrylic resin emulsion (b) were used, and in Comparative Examples 1 and 2, the acrylic resin emulsion (a ′) and the acrylic resin emulsion were used, respectively. (B ') was used as it was to prepare a hair styling solution for a test for performance to be washed.

<Washable performance (hot water)>
The above-mentioned hair styling solution for washing performance test is applied to a PET (polyethylene terephthalate) film having a thickness of 50 μm with a 100 μm applicator and dried at 23 ° C. and 50% RH for 30 minutes to obtain a coating film having a thickness of about 25 μm (when dry). Was. Drop a drop of deionized water at 60 ° C with a dropper on the coating film and rub it lightly once with a finger to draw a circle with a diameter of about 1 cm. Then, pulp waste (Nippon Paper Crecia Co., Ltd., “Kimwipe”) (Registered trademark)). Thereafter, the operation of once again dropping deionized water at 60 ° C. with a dropper and rubbing with a finger was repeated a total of 10 times. The degree of washing of the hairdressing solution in the form of a coating film was visually evaluated. The evaluation method is as follows.
(Evaluation criteria)
…: 70% or more and 100% were wiped off.
Δ: 30% or more and less than 70% were wiped off.
X: 0 to less than 30% was wiped off.

<Cleaning performance (cold water)>
The above-mentioned hair styling solution for washing performance test is applied to a PET (polyethylene terephthalate) film having a thickness of 50 μm with a 100 μm applicator and dried at 23 ° C. and 50% RH for 30 minutes to obtain a coating film having a thickness of about 25 μm (when dry). Was. One drop of deionized water at 15 ° C. was dropped on the coating film with a dropper, and after one minute, tapping was performed ten times lightly with a finger, and then a pulp waste cloth (“Kimwipe” (registered trademark) manufactured by Nippon Paper Crecia Co., Ltd.) )). The degree of washing of the hairdressing solution in the form of a coating film was visually evaluated. The evaluation method is as follows.
(Evaluation criteria)
…: 70% or more and 100% were wiped off.
Δ: 30% or more and less than 70% were wiped off.
X: 0 to less than 30% was wiped off.

  Table 1 shows the compositions of Examples 1 and 2 and Comparative Examples 1 and 2, the glass transition temperature, and the results of tests using the hairdressing solution.

  The hair styling agent using the acrylic resin emulsion obtained by the two-stage polymerization of Examples 1 and 2 has excellent styling performance (hair styling performance, hair styling performance, tactile sensation) and cleaning performance in a well-balanced manner. I understand.

  On the other hand, the acrylic resin emulsions obtained by the non-multistage polymerization of Comparative Examples 1 and 2 have good hair styling performance, re-hair styling properties, and tactile sensation, but are inferior in washability, especially in washability with cold water. You can see that there is.

  The acrylic resin emulsion for hair styling of the present invention is excellent in styling performance (hair styling performance, hair styling performance, tactile sensation) and cleaning performance in a well-balanced manner, so that various compounding agents can be used in combination and applied to various dosage forms. Is useful.

Claims (4)

An acrylic resin emulsion for a hairdressing agent, comprising an emulsion polymer of the monomer composition [I] and an emulsion polymer of the monomer composition [II],
The acrylic resin particles in the acrylic resin emulsion are dispersion-stabilized by a polyvinyl alcohol-based resin,
The polyvinyl alcohol-based resin contains a side chain 1,2-diol structural unit represented by the following formula (1),
An acrylic resin emulsion for a hairdressing agent, wherein the monomer composition [I] and the monomer composition [II] satisfy the following conditions (i) to (iii).
(I) At least one of the monomer composition [I] and the monomer composition [II] contains a (meth) acrylate-based monomer.
(Ii) The glass transition temperature (Tg2) of the emulsion polymer of the monomer composition [II] determined by the Fox equation is the glass transition temperature of the emulsion polymer of the monomer composition [I] determined by the Fox equation. (Tg1) higher than 30 ° C., the glass transition temperature (Tg1) is 0 ° C. or lower, and the glass transition temperature (Tg2) is 30 ° C. or higher.
(Iii) The blending ratio (weight ratio) of the monomer composition [I] and the monomer composition [II] is 50:50 to 99: 1 as monomer composition [I]: monomer composition [II].

(In the formula (1), R ^{1 to} R ⁶ each independently represent a hydrogen atom or an organic group, and X represents a single bond or a bond chain.) Emulsion polymerization of the monomer composition [I] is first performed using only the monomer composition [I] and the monomer composition [II], and then the monomer composition [II] is added and the monomer composition [II] is added. The method according to claim 1, wherein the emulsion polymerization is carried out. A hairdressing agent comprising the acrylic resin emulsion for a hairdressing agent according to claim 1 . A hairdressing method comprising the following steps (A) and (B).
(A) a step of applying the acrylic resin emulsion for a hairdressing agent according to claim 1 to an effective hairdressing amount and hair;
(B) a step of shaping the hair into a desired shape before, simultaneously with, and / or after the step (A).