JP2000033255A - Emulsifier for emulsion polymerization - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep stability during polymerization and the stability of a produced polymer emulsion by the use of a small amount by making a composition comprising an alkyl cyclohexanol alkylene oxide adduct of a specified formula. SOLUTION: An emulsifier form emulsion polymerization is an alkyl cyclohexanol alkylene oxide adduct expressed by the formula (wherein R1 is a 6-20C alkyl group; R2 is hydrogen atom, methyl or ethyl group; (n) is an integer of 1 or greater). In the production method, for example, an alkyl phenol alkylene oxide adduct having a structure corresponding to the alkyl-cyclohexanol alkyleneoxde adduct is subjected to nuclear hydrogenation in the presence of a hydrogenation catalyst. By the use of the emulsifier, an unsaturated monomer such as (math)acrylic acid is emulsion-polymerized in an aqueous medium. The polymerization conditions are not limited in particular, and the temperature and time of the polymerization are determined appropriately according to the kind of monomer to be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an emulsifier for emulsion polymerization. More specifically, the present invention relates to an emulsifier suitable for emulsion polymerization of an unsaturated monomer capable of maintaining the stability of a polymer emulsion produced during polymerization and using a small amount thereof.

[0002]

2. Description of the Related Art At present, polymer emulsions are superior in many aspects such as safety, workability and cost as compared with polymer organic solvent solutions, and are used in large quantities in a wide range of fields such as paints, adhesives, and fiber processing. Has been consumed.

This polymer emulsion has been produced by emulsion polymerization of an unsaturated monomer in an aqueous medium in the presence of an emulsifier. Anionic surfactants or nonionic surfactants such as higher alcohol alkylene oxide adducts and alkylphenol alkylene oxide adducts are mainly used. These emulsifiers prevent the formation of agglomerates and promote the reaction during emulsion polymerization, and improve the stability of the resulting polymer emulsion, such as chemical stability, mechanical stability, storage stability, and freeze stability. In order to maintain the content, the type and amount of the unsaturated monomer to be polymerized are appropriately selected and used depending on the type of the obtained polymer emulsion and the use of the obtained polymer emulsion.

[0004] However, the use of an anionic surfactant has a drawback that a polymer emulsion obtained is susceptible to an electrolyte and lacks chemical stability. In addition, known nonionic surfactants have the disadvantage that a large amount of surfactant must be used to maintain the stability of the resulting polymer emulsion.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an emulsifier suitable for emulsion polymerization of unsaturated monomers which can maintain the stability of a polymer emulsion produced during polymerization and the use of a small amount thereof. It is in.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, have found an emulsifier for emulsion polymerization which is optimal for the above object and completed the present invention. That is, the present invention is an emulsifier for emulsion polymerization comprising an alkylcyclohexanol alkylene oxide adduct represented by the formula (1) (formula 2).

[0007]

Embedded image (Wherein, R ¹ represents an alkyl group having 6 to 20 carbon atoms;
² represents a hydrogen atom, a methyl group or an ethyl group;
Represents an integer greater than or equal to)

[0008]

DETAILED DESCRIPTION OF THE INVENTION The emulsifier for emulsion polymerization of the present invention has the formula
Alkylcyclohexanol alkylene represented by (1)
An oxide adduct,¹Represents an atom having 6 to 20 carbon atoms.
Represents a alkyl group. R¹There is no particular limitation on the structure of
Even if it has a structure or a branched structure,
Any structure of possible structural isomers
No. Also R ¹Is bonded to an alkoxylate group (—O
(CH_TwoCHR^TwoO)_nH group) to the cyclohexane ring
Any of the second, third and fourth positions may be used. Further Al
Kill group R¹Cis, tran
There are structural isomers of both, but either of them may be used.

Further, an oxyalkylene unit (—CH ₂
R ² in the (CHR ² O—unit) represents a hydrogen atom, a methyl group or an ethyl group, and specifically, the oxyalkylene unit is an oxyethylene unit (—CH ₂ CH ₂ O— unit) and an oxypropylene unit (—CH ₂ CH (CH ₃ ) O— unit) or oxybutylene unit (—CH ₂ CH (CH ₂ CH ₃ ) O)
−unit). n is an integer of 1 or more. When n is 2 or more, the repeating unit may have only one of an oxyethylene unit, an oxypropylene unit, and an oxybutylene unit, or may have two or more types. It may have an oxyalkylene unit. When it has two or more types of oxyalkylene units, it may be added randomly or in blocks.

Although the range of n is not limited, it is usually 1 to 100.
And is appropriately selected depending on the kind of the unsaturated monomer to be polymerized. Structural isomers of R ¹ to alkylcyclohexanol alkylene oxide adduct, regioisomers and cis R ¹ and alkoxylate group, trans isomer, and has a different compound types and numbers of oxyalkylene units which are alone Although it can be used, it is usually a mixture of two or more. Further, a mixture of two or more kinds of alkylcyclohexanolalkylene oxide adducts having different numbers of carbon atoms in the alkyl group R ¹ may be used.

Formula (1) which is the emulsifier for emulsion polymerization of the present invention
The alkylcyclohexanolalkylene oxide adduct represented by the formula may be produced by any method. In general, 1) a method of hydrogenating an alkylphenol alkylene oxide adduct having a structure corresponding to the alkylcyclohexanol alkylene oxide adduct of the formula (1) in the presence of a hydrogenation catalyst, and 2) a method of alkylating the alkyl of the formula (1) After the alkylphenol alkylene oxide adduct having a structure corresponding to the cyclohexanol alkylene oxide adduct is subjected to nuclear hydrogenation in the presence of a hydrogenation catalyst, the resulting alkylcyclohexanol alkylene oxide adduct and the alkylene oxide are reacted in the presence of a catalyst. 3) The alkylphenol having a structure corresponding to the alkylcyclohexanolalkylene oxide adduct of the formula (1) is subjected to nuclear hydrogenation in the presence of a hydrogenation catalyst, and the resulting alkylcyclohexanol and alkylene oxide are converted to Obtained by the method such as a method of reacting in the presence of a medium.

Specific examples of unsaturated monomers that can be emulsion-polymerized using the emulsifier for emulsion polymerization of the present invention include, for example,
(Meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate,
Acrylic unsaturated monomers such as 2-ethylhexyl (meth) acrylate, (meth) acrylonitrile, and (meth) acrylamide, for example, vinyl ester unsaturated monomers such as vinyl acetate, for example, vinyl chloride, vinylidene chloride , Vinyl halide unsaturated monomers such as vinyl bromide,
For example, aromatic unsaturated monomers such as styrene and α-methylstyrene, for example, olefinically unsaturated monomers such as ethylene, propylene, butadiene, and chloroprene are exemplified. These unsaturated monomers may be used alone.
More than one type can be used simultaneously.

When the emulsion polymerization is carried out using the emulsifier for emulsion polymerization of the present invention, the amount of the emulsifier used is usually 0.1 to 20 parts by weight, preferably 0 to 20 parts by weight, per 100 parts by weight of the unsaturated monomer used for the polymerization. 2 to 10 parts by weight. In addition, as long as the effect of the present invention is not impaired, it may be used in combination with a commonly used anionic or nonionic surfactant or a protective colloid such as polyvinyl alcohol and hydroxyethyl cellulose.

The polymerization conditions for emulsion polymerization in an aqueous medium using the emulsifier for emulsion polymerization of the present invention may be carried out according to ordinary conditions. The polymerization temperature and the polymerization time vary depending on the kind of the unsaturated monomer used, but usually the polymerization temperature is 20 to 15
The temperature is in the range of 0 ° C. and the polymerization time is in the range of 0.5 to 20 hours. Any known polymerization initiator may be used. Specifically, for example, inorganic peroxides such as hydrogen peroxide, ammonium persulfate, and sodium persulfate; for example, organic peroxides such as benzoyl peroxide and peracetic acid; Oxides, for example, azo compounds such as azobisisobutyronitrile and azobisdimethylvaleronitrile can be used. Further, a redox initiator using a reducing agent such as sodium hydrogen sulfite, sodium thiosulfate, and ferrous sulfate as a polymerization accelerator may be used.

The polymerization may be carried out according to a conventional emulsion polymerization method. For example, an unsaturated monomer or unsaturated monomer may be added to an aqueous medium containing the emulsifier for emulsion polymerization of the present invention maintained at the above-mentioned temperature. An emulsion emulsified in an aqueous medium using an emulsifier for emulsion polymerization of the above, and the polymerization initiator may be fed continuously to carry out polymerization. And polymerization may be carried out. The concentration of the unsaturated monomer at the time of the emulsion polymerization may be appropriately determined according to the use of the obtained polymer emulsion, but is generally in the range of 20 to 70% by weight.

[0016]

Next, the present invention will be described in more detail by way of examples. Production Example 1 In a 1000 ml autoclave equipped with an ethylene oxide inlet tube, 55 g (0.25) of nonylphenol (nonyl group is a mixture having a branched structure and an ortho / para ratio is 1/9)
mol) and 0.48 of a 40% aqueous sodium hydroxide solution
g (4.8 mmol of sodium hydroxide). After the atmosphere in the system was replaced with nitrogen, the temperature was raised to 120 ° C.
The pressure was reduced to 0 mmHg, and the solution was dehydrated under reduced pressure for 1 hour. After completion of the dehydration under reduced pressure, the inside of the system was returned to normal pressure with nitrogen, and the temperature was raised to 150 ° C.
g (7.49 mol) with a gauge pressure of 0.2 to 0.4 MP
The mixture was fed into the reaction system over 7 hours under the pressure of a to perform an ethoxylation reaction of nonylphenol. After completion of the feeding of ethylene oxide, the mixture was further aged at the same temperature for 1 hour, cooled, and neutralized with 0.30 g (5.0 mmol) of acetic acid to obtain 660 g of a nonylphenol ethylene oxide adduct. Of the resulting nonylphenol ethylene oxide adduct,
The average addition mole number of ethylene oxide to nonylphenol (hereinafter, simply referred to as ethylene oxide addition mole number) is 30.0.

Subsequently, 200 g of a nonylphenol ethylene oxide adduct having a mole number of 30.0 of ethylene oxide obtained in a 1000 ml autoclave (129.
7 mmol (the number of moles of the nonylphenoxy skeleton)) and 20.0 g of a 5% by weight ruthenium carbon powder were charged. After the inside of the system was replaced with nitrogen and then with hydrogen, the temperature was raised to 120 ° C. The hydrogen pressure was adjusted to a gauge pressure of 5.0 MPa, and a nuclear hydrogenation reaction was performed at the same temperature for 5 hours while continuously supplying hydrogen so as to maintain the same pressure. After completion of the reaction, the catalyst was filtered under pressure at 80 ° C. while hot. The filtrate was further cooled to room temperature to yield a colorless semi-solid. ¹ H and ¹³ C-NM
As a result of measurement of R, elemental analysis, mass spectrometry and infrared spectrum, this semi-solid had an average addition mole number of ethylene oxide to nonylcyclohexanol (hereinafter simply referred to as ethylene oxide addition mole number) of 30.
A nonylcyclohexanol ethylene oxide adduct of 0 was identified.

The amount of hydrogen consumed during the reaction is 391.7
It was 3.02 mol times with respect to the charged nonylphenol ethylene oxide adduct. In addition, the amount of nonylphenol ethylene oxide adduct remaining in the nonylcyclohexanol ethylene oxide adduct was determined by liquid chromatography, and the amount was 140 ppm by weight. Further, nonylcyclohexane produced by the hydrogenolysis reaction was quantified by gas chromatography to find that the amount was 160 ppm by weight.

EXAMPLE 1 120 g of water was placed in a 500 ml flask equipped with a thermometer, a stirrer, three dropping funnels, a gas inlet tube and a reflux condenser.
2 g of the nonylcyclohexanol ethylene oxide adduct obtained in Production Example 1 was charged as an emulsifier, and heated to 60 ° C. under a nitrogen stream. Then, while maintaining the same temperature, an unsaturated monomer mixture of butyl acrylate and styrene (1 /
Polymerization was started by separately adding 16 g of a 1% by weight), 1.0 g of an aqueous solution containing 5% by weight of sodium persulfate, and 1.0 g of an aqueous solution containing 2.5% by weight of sodium hydrogen sulfate from separate dropping funnels at once. Thereafter, 64 g of the unsaturated monomer mixture was further added dropwise over 2 hours, and simultaneously 5.7 g of an aqueous solution containing 5% by weight of sodium persulfate and 5.7 g of an aqueous solution containing 2.5% by weight of sodium hydrogen sulfate were taken over 3 hours. It was dropped. After completion of the dropwise addition, the mixture was further maintained at the same temperature for 2 hours to complete the polymerization, thereby obtaining a polymer emulsion.

(Stability at the time of polymerization) The obtained polymer emulsion was filtered through an 80-mesh wire gauze, and the obtained solid was washed with water, dried and weighed. A solid content of 0.38% by weight relative to the charged unsaturated monomer was formed.

(Chemical stability) The obtained polymer emulsion was diluted to 1% by weight with water, and 0.5 mol / l
Was added dropwise, and the concentration of calcium chloride in the emulsion at the time when the aggregation of the emulsion particles started was determined. 42 mmol / l.

Comparative Example 1 An emulsion polymerization was carried out in the same manner as in Example 1 except that sodium lauryl sulfate was used instead of the nonylcyclohexanol ethylene oxide adduct obtained in Production Example 1. The performance of the polymer emulsion was evaluated in the same manner as in Example 1.

(Stability at the time of polymerization) A solid content of 0.86% by weight was found based on the charged unsaturated monomer. (Chemical stability) The calcium chloride concentration in the emulsion at the time when the aggregation of the emulsion particles starts is 15 mmol.
/ L.

[0024]

The emulsifier for emulsion polymerization of the present invention can maintain high stability of the polymerization of unsaturated monomers and the stability of the resulting polymer emulsion by using a small amount of the unsaturated monomer. It is suitable as an emulsifier at the time of polymerization of a body.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masui Oita 1-6-6 Takasago, Takaishi-shi, Osaka Mitsui Chemicals, Inc. (72) Inventor Kyokichi Watanabe 1-6 Takasago, Takaishi-shi, Osaka Mitsui Chemicals, Inc. F term (reference) 4D077 AA05 AB03 AB06 AB15 AB20 AC03 BA03 BA15 DC03Y DC19X DC19Y DC20X DC20Y DD32Y DD33Y DE03Y DE07X DE08X 4J011 KA12 KA15

Claims (1)

[Claims] An emulsifier for emulsion polymerization comprising an alkylcyclohexanolalkylene oxide adduct represented by the formula (1) (formula 1). Embedded image (Wherein, R ¹ represents an alkyl group having 6 to 20 carbon atoms;
² represents a hydrogen atom, a methyl group or an ethyl group;
Represents an integer greater than or equal to)