JP2000344806A - Surfactant composition for emulsion polymerization - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surfactant composition for emulsion polymerization having good stability during polymerization and mechanical stability of an emulsion, small particle size and low viscosity. (A) A monovalent cation salt of a polyaromatic compound polysulfonate having two or more aromatic rings in one molecule and at least one of the aromatic rings having an aliphatic hydrocarbon group as a substituent And (b) represented by the general formula (I),
A compound having a CMC in the range of 1 × 10 ^{−5 to} 0.02 mol L ⁻¹ is an essential component, and the weight ratio of the component (a) to the component (b) is (a) /
(b) A surfactant composition for emulsion polymerization in which 5/95 to 75/25. RO- (AO) _n -SO ₃ M (I) (wherein, R is a monovalent aliphatic hydrocarbon group, and A is
An alkylene group of 4, n is a number of 1 to 50, and M is a monovalent cation. )

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a surfactant composition for emulsion polymerization.

[0002]

2. Description of the Related Art
In the case of emulsion polymerization of vinyl monomers, etc., non-ionic surfactants such as polyoxyethylene alkyl ether and polyoxyethylene alkyl phenyl ether, alkyl benzene sulfonates, alkyl sulfates, and polyoxyethylene alkyl ether sulfates Anionic surfactants such as salts, polyoxyethylene alkylphenyl ether sulfates, and higher fatty acid salts have been used.

[0003] Among them, surfactants having a low critical micelle concentration (hereinafter referred to as CMC) which are effective in a small amount have been used. On the other hand, a surfactant having a high CMC was not suitable as a surfactant for emulsion polymerization.

The performance required of these surfactants for emulsion polymerization is that the stability during polymerization and the mechanical stability of the emulsion are good, the particle size of the emulsion is small, and the viscosity is low. A surfactant satisfying all of these properties has not been obtained.

[0005] An object of the present invention is to provide a surfactant composition for emulsion polymerization which satisfies all the above-mentioned properties.

[0006]

The present invention relates to (a) a polyaromatic compound having two or more aromatic rings in one molecule, at least one of which has an aliphatic hydrocarbon group as a substituent. A monovalent cation salt of an aromatic compound polysulfonate, and
(b) represented by the general formula (I) and having a CMC of 1 × 10 ^{−5 to} 0.02 m
olL- ^{1 in} the range of an essential component, and the component (a)
Provided is a surfactant composition for emulsion polymerization, wherein the weight ratio of the component (b) is (a) / (b) = 5/95 to 75/25.

RO- (AO) _n -SO ₃ M (I) (wherein, R is a monovalent aliphatic hydrocarbon group, and A is C 2 -C 2)
4, an alkylene group, n is a number of 1 to 50 indicating the average number of moles of alkylene oxide added, M is a monovalent cation, and n A's may be the same or different. )

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the component (a) of the present invention, examples of the aromatic ring include a benzene ring and a naphthalene ring. The aliphatic hydrocarbon group which is a substituent of the aromatic ring is such that the aromatic ring is a benzene ring. In this case, a straight-chain or branched-chain monovalent aliphatic hydrocarbon group having 8 to 14 carbon atoms is preferable. When the aromatic ring is a naphthalene ring, a straight-chain or branched-chain monovalent aliphatic hydrocarbon group having 1 to 4 carbon atoms is preferable. Groups are preferred. Further, the polyaromatic compound has two or more, preferably 2 to 10 aromatic rings as described above in one molecule, and specifically, an aromatic compound having an aliphatic hydrocarbon group as a substituent. Compounds, or an ether compound obtained by etherifying an aromatic compound having an aliphatic hydrocarbon group as a substituent and another aromatic compound, an aromatic compound having an aliphatic hydrocarbon group as a substituent and formaldehyde Examples include a condensed formalin condensate, and a formalin cocondensate obtained by cocondensing an aromatic compound having an aliphatic hydrocarbon group as a substituent with another aromatic compound and formaldehyde.

The sulfonation of the polyaromatic compound is carried out using a sulfonating agent such as concentrated sulfuric acid, fuming sulfuric acid, SO ₃ gas or the like. The degree of sulfonation of the polyaromatic compound is 0.5 to 1.5 per aromatic ring. Is particularly preferable, and 1 is particularly preferable. The order of the sulfonation reaction and the reaction such as the formalin condensation is not specified, and either one may be performed first. The polyaromatic ether compound is preferably sulfonated after etherification, and the formalin condensate is preferably subjected to a condensation reaction after sulfonation. The monovalent cation salt is sodium,
Preferred are alkali metal salts such as potassium; ammonium salts; and amine salts such as alkanolamines.

Particularly preferred component (a) is a salt of isododecyl diphenyl ether disulfonate, a salt of a formalin co-condensate of butyl naphthalene sulfonic acid and naphthalene sulfonic acid, a salt of a formalin condensate of methyl naphthalene sulfonic acid, and the like. A single type or a combination of two or more types may be used.

The component (b) is represented by the general formula (I):
CMC is 1 × 10 ^{−5 to} 0.02 mol L ⁻¹ , preferably 0.001 to
The compound is in the range of 0.01 molL ^-1 and may be used alone or in combination of two or more. In the present invention, CMC is a value measured by an electric conductivity titration method.

In the general formula (I), R has 10 to 2 carbon atoms.
4, 11 to 18 linear or branched monovalent aliphatic hydrocarbon groups, particularly alkyl groups are preferred. A is preferably an ethylene group or a propylene group. When two or more alkylene oxides are added, any of random addition and block addition may be used. Further, both of the adding methods may be combined. n is preferably a number of 3 to 30. M is sodium,
Alkali metals such as potassium; ammonium; amines such as alkanolamines are preferred.

The compound represented by the general formula (I) is obtained, for example, by adding an alkylene oxide such as ethylene oxide or propylene oxide to an aliphatic monohydric alcohol,
It can be produced by sulfating with a sulfonating agent such as SO ₃ gas and neutralizing with NaOH or the like.

In the composition of the present invention, the mixing ratio of the component (a) to the component (b) is (a) / (b) = 5/95 to 75/25, preferably 10/90 to 50 by weight. / 50. When (a) / (b) is less than 5/95, the viscosity of the emulsion becomes high and the mechanical stability is not sufficient. If it exceeds 75/25, the particle size becomes too large, and the polymerization stability and mechanical stability are not sufficient.

[0015] Specific examples of monomers which can be subjected to emulsion polymerization using the surfactant composition of the present invention include styrene, α
-Aromatic vinyl monomers such as methylstyrene and chlorostyrene: acrylates such as methyl acrylate, ethyl acrylate and butyl acrylate: methacrylates such as methyl methacrylate and ethyl methacrylate:
Vinyl halides such as vinyl chloride, vinyl bromide, vinylidene chloride and vinylidene chlorides: vinyl esters such as vinyl acetate and vinyl propionate: nitriles such as acrylonitrile and methacrylonitrile: conjugated dienes such as butadiene and isoprene And so on. These monomers may be used alone or in combination of two or more. The surfactant composition of the present invention is used in an amount of 0.1 to 20 parts by weight per 100 parts by weight of the monomer.
It is preferably used in an amount of 0.5 parts by weight, especially 0.5 to 5 parts by weight.

The surfactant composition of the present invention comprises a nonionic surfactant such as polyoxyethylene (ethylene oxide addition mole number 0 to 100) alkyl or alkenyl (alkyl or alkenyl group having 12 to 24 carbon atoms) ether. They can be used together. Further, a water-soluble protective colloid or the like can be used in combination.

The emulsion polymerization conditions using the surfactant composition of the present invention are not particularly limited, and the amount of the monomer is preferably 20 to 70% by weight, particularly preferably 40 to 50% by weight, based on the whole system. Further, it can be used in any emulsion polymerization method such as a monomer dropping method, a monomer batch charging method and a pre-emulsion method.

[0018]

Examples 1 to 8 and Comparative Examples 1 to 9 The following components (a-1) to (a-3) as components (a) and the following components (b-1) to (b-4) as component (b) , A comparative compound (hereinafter referred to as component (c))
Using the following (c-1), the surfactant composition of the present invention and the comparative surfactant composition were produced at the compounding ratio shown in Table 1.

(A-1): Na salt of isododecyl diphenyl ether disulfonate [Perex, trade name, manufactured by Kao Corporation]
SS-H] (a-2): Na salt of a formalin cocondensate of butyl naphthalene sulfonic acid and naphthalene sulfonic acid [Demol SNB manufactured by Kao Corporation] (a-3): Condensation of methyl naphthalene sulfonic acid formalin object of Na salt [manufactured by Kao Corporation, trade name Demol MS] _{(b-1): C 12} H 25 O (CH 2 CH 2 O) 18 SO 3 Na CMC 0.0046m
^{olL -1 (b-2):} C 14 H 29 O (CH 2 CH 2 O) 18 SO 3 Na CMC 0.0012m
^{olL -1 (b-3):} C 12 H 25 O (CH 2 CH 2 O) 12 SO 3 Na CMC 0.004 m
olL ^-1

[0020]

Embedded image

(C-1): linear dodecylbenzene sulfonic acid
Na salt [manufactured by Kao Corporation, trade name Neoperex F-25] Here, CMC was measured by the following method.

<Measurement method of CMC> 100 mL of distilled water was placed in a beaker and the electric conductivity was measured with stirring.
]. Use a surfactant solution that has been adjusted to a predetermined concentration in advance.
0.2 mL of the solution was dropped into the beaker, and the electrical conductivity was read each time the solution was dropped. Set the surfactant concentration of the titrant to x molL
^-1 , If the amount of the titrant dropped is ymL, the surfactant concentration C in the solution in the beaker is C = xy · (100 + y)
Becomes The inflection point when the electric conductivity is plotted against C is CMC (temperature 25 ° C.).

Using the obtained surfactant composition, emulsion polymerization was carried out by the monomer dropping method shown below, and the obtained polymer emulsion was evaluated by the following method. Table 1 shows the results
Shown in

(1) Polymerization Stability (Aggregate Amount) The polymer emulsion was filtered through a 200-mesh stainless steel wire gauze. Aggregates adhering to the reactor wall, stirring blades, etc. after polymerization were collected, filtered in the same manner, and washed with water. After 26.6kPa, 105 ℃
For 2 hours and weighed to determine the amount of aggregates. The polymerization stability was expressed in terms of% by weight of the aggregate based on the total amount of the monomers used.

(2) Mechanical stability 50 g of the polymer emulsion was weighed with a Malon stability tester at 10 k.
g, rotated at 1000 r / min for 5 minutes, the formed aggregate was filtered through a 200-mesh stainless steel wire gauze, and the filter residue was washed with water, dried and weighed at 26.6 kPa and 105 ° C. displayed.

(3) Viscosity The viscosity of the polymer emulsion was measured using a B-type viscometer at a temperature of 25 ° C. and a rotation speed of 12 r / min.

(4) Average Particle Size The average particle size of the polymer emulsion particles was measured using a dynamic light scattering particle size analyzer N-4SD manufactured by Coulter Corporation.

<Monomer Dropping Method> 316.25 g of ion-exchanged water, 8.75 g of a surfactant composition, and 0.35 g of potassium persulfate were charged into a separable flask, and stirred in a nitrogen stream for 30 minutes. 0.9 g of acrylic acid and 174.1 g of butyl acrylate were mixed, and 8.75 g of the mixed monomer was charged in the above flask, and then placed in a water bath at 60 ° C. and heated. When the temperature reached 58 ° C., the remaining mixed monomer was added dropwise over 2 hours. During this time, the temperature in the flask was kept at 60 ± 2 ° C. After completion of the dropping, the mixture was aged at 60 ° C. for 3 hours, and then cooled to room temperature to obtain a polymer emulsion.

[0029]

[Table 1]

Examples 9 to 15, Comparative Examples 10 to 18 (a) to (a-1) to (a-3) as components, and (b-1) to (b-4) as components (b). Using the above (c-1) as the component (c), surfactant compositions of the present invention and comparative surfactants were produced at the compounding ratios shown in Table 2. Using the obtained surfactant composition, emulsion polymerization was carried out by the batch charging method shown below, and the obtained polymer emulsion was evaluated by the above method. Table 2 shows the results.

<Batch Preparation Method> A separable flask was charged with 316.25 g of ion-exchanged water, 8.75 g of a surfactant composition, and 0.35 g of potassium persulfate, and stirred in a nitrogen stream for 30 minutes. After charging 175 g of styrene monomer into the above flask, the flask was placed in a water bath at 65 ° C. and heated. The temperature in the flask is about
When the temperature reached 62 ° C., the polymerization reaction started. The temperature in the flask was maintained at 65 ± 2 ° C. for 5 hours to complete the polymerization reaction, and a polymer emulsion was obtained.

[0032]

[Table 2]

Examples 16 to 26, Comparative Examples 19 to 27 (a) The components (a-1) to (a-3) as components, and the components (b-1) to (b-4) as components (b). Using the above (c-1) as the component (c), surfactant compositions of the present invention and comparative surfactants were produced at the compounding ratios shown in Table 3. Using the obtained surfactant composition, emulsion polymerization was carried out by the following pre-emulsion method, and the obtained polymer emulsion was evaluated by the above method. Table 3 shows the results.

<Pre-emulsion method> Acrylic acid 2.5
g, butyl acrylate 123.75 g, methyl methacrylate 12
3.75 g was mixed to prepare a monomer mixture. 5.0 g of surfactant composition and 0.50 g of potassium persulfate were dissolved in 107.1 g of ion-exchanged water, and the above monomer mixture was mixed with the mixture, and the mixture was emulsified with a homomixer at 5000 r / min for 10 minutes to obtain a uniform monomer emulsion. I got 137.9 g of ion-exchanged water and 36.2 g of the above-mentioned monomer emulsion were charged into a separable flask, and stirred in a nitrogen stream for 30 minutes. Then heat the flask to 80 ° C
In a water bath and heated. Initial polymerization was performed for 30 minutes, and the remaining monomer emulsion was added dropwise over 2 hours. During this time, the temperature in the flask was kept at 80 ± 2 ° C. After completion of the dropwise addition, the mixture was aged for 3 hours at 80 ° C., and then cooled to room temperature to obtain a polymer emulsion.

[0035]

[Table 3]

[0036]

When the surfactant composition of the present invention is used as an emulsifier for emulsion polymerization, the amount of aggregates generated during the polymerization reaction is small (that is, the polymerization stability is good), and the mechanical stability of the obtained emulsion is improved. An emulsion having good properties, small particle size and low viscosity can be obtained.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasuo Ishii 1334 Minato, Wakayama-shi, Wakayama Prefecture F-term in the Kao Research Laboratory (Reference) 4D077 AB14 BA07 BA13 BA20 DC02Y DC04Y DC12Z DC19Y DC57Y DC64Y DD32Y DE02Y DE04Y DE07Y DE29Y 4J011 KA02 KA02 KA02 KA02 KA02 KA07

Claims (1)

[Claims] 1. (a) Monovalent cation of a polyaromatic compound polysulfonate having two or more aromatic rings in one molecule and at least one of the aromatic rings having an aliphatic hydrocarbon group as a substituent A salt, and (b) represented by the general formula (I),
A compound having a CMC in the range of 1 × 10 ^{−5 to} 0.02 mol L ⁻¹ is an essential component, and the weight ratio of the component (a) to the component (b) is (a) /
(b) A surfactant composition for emulsion polymerization in which 5/95 to 75/25. RO- (AO) _n -SO ₃ M (I) (wherein, R is a monovalent aliphatic hydrocarbon group, and A is
4, an alkylene group, n is a number of 1 to 50 indicating the average number of moles of alkylene oxide added, M is a monovalent cation, and n A's may be the same or different. )