JPH0519562B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of the Invention] The present invention relates to polymer particles made of a copolymer obtained by grafting a polymerizable monomer to a conjugated diene polymer containing a high proportion of unsaturated hydrocarbon groups in its side chains. The present invention relates to a method for producing an aqueous dispersion containing dispersed components. [Prior Art] Many studies have been conducted on the production of polymers using transition metals as catalysts since the appearance of Ziegler catalysts. Polymers obtained by polymerization using transition metals as catalysts are characterized by extremely high regularity in their microstructures, and are useful in a variety of applications. However, the synthesis of such polymers cannot be carried out in an aqueous system due to the problem that the presence of oxygen or moisture in the reaction system deactivates the catalyst, and in the end, solution polymerization methods have no choice but to be used. This is the current situation. On the other hand, one of the methods for modifying rubber or resin is the graft copolymerization method, which allows polymers with different properties to be reacted and bonded to obtain a copolymer that retains the excellent properties of each polymer. Are known. In order to produce a graft copolymer using the polymer obtained by the above-mentioned transition metal-catalyzed polymerization, since this polymer can be obtained in a solution state as described above, it is necessary to Copolymerization must be carried out in a solution system, which causes various problems as described below. (1) The viscosity of the reaction solution increases as the polymerization reaction progresses, making stirring and temperature control of the solution insufficient, making it difficult to obtain a graft copolymer with desired properties. . (2) Among polymers obtained by polymerization using transition metals as catalysts, those with particularly high crystallinity and high melting points have low solubility in solvents and therefore maintain a stable solution state. Therefore, it is practically difficult to carry out the polymerization reaction. (3) Since the resulting graft copolymer is in a solution state, it is not easy to separate it, and the solvent must be recovered, which results in complicated handling and poor work efficiency, as well as poor performance in the application. There are also limits. For these reasons, there is a strong desire for the emergence of a graft copolymer of a crystalline polymer obtained by polymerization using a transition metal as a catalyst, or an aqueous dispersion containing this as a dispersed phase. [Object of the Invention] The present invention has been made against the above-mentioned background, and its object is to provide a material with a high proportion of unsaturated hydrocarbon groups in its side chain, which is useful for various uses. It is an object of the present invention to provide a production method that can efficiently and easily produce an aqueous dispersion in which the dispersed phase is a graft copolymer obtained by grafting a polymerizable monomer to a polymer having the present invention. [Structure of the Invention] The method for producing an aqueous dispersion of a polymer according to the present invention is characterized in that the following first and second stage polymerization steps are carried out in an aqueous dispersion medium. 1st stage: (A) a cobalt compound and (B) an organometallic compound or hydride of a metal from Groups 1 to 3 of the periodic table, at a ratio of 1 to 1000 to the cobalt compound (A).
The first catalyst component obtained by contacting in the presence of twice the molar amount of conjugated diene monomer is dispersed in an aqueous dispersion medium, and then the conjugated diene monomer and (C) carbon disulfide, phenyl isothiocyanic acid and a second catalyst component consisting of at least one compound selected from the group of xanthogen compounds, and the conjugated diene monomer is polymerized, so that the conjugated diene monomer has 70% or more of unsaturated hydrocarbon groups in the side chain. A polymerization process to obtain an aqueous dispersion of a conjugated diene polymer. Second stage: In the presence of the polymer obtained in the first stage, by reacting a conjugated diene monomer and/or other polymerizable monomers, these monomers are added to the polymer. Polymerization process for grafting. The present invention will be explained in detail below. In the production method of the present invention, in the first stage polymerization step described in detail later, a conjugated diene monomer is polymerized in an aqueous dispersion medium, and a crystalline polymer having 70% or more of unsaturated hydrocarbon groups in the side chain is polymerized. A combined emulsion or suspension (hereinafter simply referred to as "aqueous dispersion") is produced, and then, in the second stage polymerization step, the aqueous dispersion of the polymer obtained in the first stage polymerization step and By performing a reaction treatment in the coexistence of a conjugated diene monomer and/or other polymerizable monomers, a copolymer with the crystalline polymer as a backbone grafted with a polymerizable monomer can be produced. A combined aqueous dispersion is obtained. The characteristic feature of the polymerization process for synthesizing the first-stage crystalline polymer is that the catalyst used is
It is a specific catalyst that is composed of a catalyst component and a second catalyst component, and exhibits catalytic action only when both catalyst components are combined, and each of these catalyst components is further processed in the following steps () and (). ) is added stepwise to the reaction system dispersion to carry out polymerization. Step (): A solution of the first catalyst component is dispersed in water in the presence of an emulsifier and/or a suspension protectant to form an aqueous dispersion, and minute oil droplets are formed from the solution of the first catalyst component. form a group. Step (): A conjugated diene monomer is added to the system obtained in step (), and a second catalyst component is further added to perform polymerization. The first catalyst component includes (A) a cobalt compound and (B)
An organometallic compound or hydride formed by a metal from Groups 1 to 3 of the periodic table, as described in (A) above.
It is obtained by contacting the cobalt compound in the presence of a conjugated diene monomer in an amount of 1 to 1000 times the mole. Further, the second catalyst component includes (C) carbon disulfide,
It consists of at least one compound selected from phenylisothiocyanate and xanthogen compounds. Examples of the cobalt compound (A) for forming the first catalyst component include cobalt octylate,
Organic acid salts such as cobalt naphthenate, cobalt benzoate, cobalt oxalate, cobalt malonate, and cobalt acetate; cobalt complexes such as cobalt bisacetylacetonate, cobalt trisacetylacetonate, and cobalt acetoacetate ethyl ester; and cobalt bromide. Triarylphosphine complexes of cobalt halides such as triphenylphosphine complexes, tri-m-tolylphosphine complexes of cobalt bromide, tri-m-xylylphosphine complexes of cobalt bromide, pyridine complexes of cobalt chloride, cobalt chloride Pyridine derivative complexes of cobalt halides such as β-picoline complexes, ethyl alcohol complexes of cobalt chloride, (1,3-butadiene)
[1-(2-methyl-3-butenyl)-π-allyl]
Cobalt, tris-π-allyl cobalt, bicyclo-[3,3,0]-octidienyl-1,5-cyclooctadiene cobalt, bis-(π-allyl)
- Halogenocobalt (however, as a halogen, I,
Either Br or Cl. ), monovalent or zero-valent cobalt complexes such as octacarbonyl dicobalt. These cobalt compounds can be used alone or in combination of two or more. As the (B) organometallic compound or hydride of a metal in groups 1 to 10 of the periodic table for forming the first catalyst component, a compound that reduces a cobalt compound is preferably used. Metals from Groups to Groups of the periodic table include a, b, a, b, a,
Metals of group b can be used, among which metals a, a,
Group a is preferable, and preferable metals include Li, Na, K, Mg, Zn, and Al.
Particularly preferred metals include Li and Al.
Preferred organometallic compounds or metal hydride compounds include alkyl derivatives having 1 to 6 carbon atoms or hydrogenated derivatives of the above metals, such as ethyllithium, n-butyllithium, sec-butyllithium, t-butyllithium, etc. Organolithium compounds, organozinc compounds such as diethylzinc and dimethylzinc, organomagnesium compounds such as butylmagnesium chloride, ethylmagnesium bromide, dibutylmagnesium and dihexylmagnesium, trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum , organoaluminum compounds such as tridodecylaluminum, diethylaluminum chloride, diisobutylaluminum chloride, ethylaluminum sesquichloride, ethylaluminum dichloride, tetraethylaluminoxane, and metal hydride compounds such as lithium aluminum hydride, sodium boron hydride, lithium boron hydride. I can do it. These metal compounds can be used alone or in combination of two or more. Furthermore, as the conjugated diene monomer used for preparing the first catalyst component, those having 4 to 5 carbon atoms, such as butadiene and isobrene, are particularly preferable. The method of preparing the solution of the first catalyst component is extremely important. The method for preparing a solution of catalyst components is as follows: First, in the presence of a conjugated diene monomer, a specific amount of (A) a cobalt compound (B) and an organometallic compound or a metal hydride compound of the periodic table or group are mixed. It is about contact and reaction. During this preparation,
The amount of conjugated diene monomer used is (A) cobalt compound 1
It is preferably 1 to 1000 mol, more preferably 6 to 300 mol, and (B) periodic table No.
The amount of the organometallic compound or metal hydride compound of the group (A) is preferably 0.3 to 100 mol, more preferably 0.9 mol per mol of the cobalt compound (A).
~50 moles. Temperature during preparation ranges from -78℃ to 100℃
The temperature is preferably -30°C to 50°C. By stirring the solvent and catalyst component as necessary during preparation, the reaction between (A) the cobalt compound and (B) the organometallic compound or hydrogen metal compound can be uniformly carried out. As the solvent for preparing the solution of the first catalyst component, an inert solvent or a polymerizable monomer can be used. Such an inert solvent preferably has a solubility in water of less than 10 ^-3 % by weight, easily absorbs the conjugated diene monomer added in step (), and acts as an absorption aid for the monomer. Examples of such solvents include n-hexane, n-heptane, n-pentane, refined kerosene, and the like. When this solvent is used together with a solvent such as toluene, xylene, cyclohexane, etc., which has a solubility in water of more than 10 ^-3 % by weight, a solvent with a solubility in water of 10 ^-3 % by weight or less is added in step (). It is preferably used in an amount of 1000 parts by weight or less, more preferably 300 parts by weight or less, per 100 parts by weight of the conjugated diene monomer. Furthermore, examples of polymerizable monomers that can be used as a solvent include highly polar monomers such as vinyl acetate, unsaturated nitriles, and ethylenically unsaturated carboxylic acid alkyl ethers. However, when reducing a cobalt compound with an organometallic compound of a metal from Groups 1 to 3 of the periodic table, the polymerizable monomer that reacts with the organometallic compound such as ethylenically unsaturated carboxylic acid alkyl ester is It is preferable to add the catalyst component 1 after it is prepared. (C) carbon disulfide constituting the second catalyst component;
Although there are no particular restrictions on the use of phenylisothiocyanic acid and xanthogen compounds, it is desirable to remove dissolved oxygen by bubbling with nitrogen gas or the like prior to use. The xanthogen compound has the general formula

〔Effect of the invention〕

According to the production method of the present invention, in the first stage polymerization step, a solution of the first catalyst component is dispersed in advance, and the conjugated diene monomer and the second catalyst component are dispersed in the dispersed phase.
A conjugated diene polymer having a high proportion of unsaturated hydrocarbon groups in the side chain is formed by absorbing the catalyst component of Because the polymerizable monomers are graft copolymerized, it is possible to produce a high yield of an aqueous dispersion of a graft copolymer of a crystalline conjugated diene polymer, which is extremely useful industrially, as is clear from the examples described below. can be easily manufactured at high rates. The particle size of the formed polymer particles is controlled by regulating the particle size of oil droplets or seeds formed by the solution of the first catalyst component used in the first stage polymerization step. As a result, an aqueous dispersion with excellent dispersion stability and high industrial utility value can be obtained. In addition, the aqueous dispersion of the polymer obtained by the present invention is a graft copolymer of a conjugated diene polymer having high crystallinity and properties such as a high melting point and excellent mechanical strength and solvent resistance. Furthermore, these polymer particles are homogeneously dispersed, have good dispersion stability, and can be used in a wide variety of applications. Particularly suitable for applications in which the aqueous dispersion is used, such as paper coating compositions, carpet backing agents, asphalt compositions, foam rubbers, paints, adhesives, etc., and organic fillers for rubbers or resins. It is effective in improving and modifying the strength and heat resistance of these various materials. [Embodiments of the Invention] Examples of the present invention will be described below, but the present invention is not limited thereto. Example 1 7.5 ml of a solution of 0.2 mol of cobalt octylic acid in n-hexane was poured into a 100 ml pressure bottle that had been purged with nitrogen in advance, and then 11 ml of cyclohexane was added.
A magnetic rotor was inserted and the cap was capped. After adding 2.6 ml of 1,3-butadiene (room temperature 20°C), in ice
The magnetic rotor was rotated vigorously while cooling for 10 minutes. This is triisobutylaluminum
Add 9.0ml of 0.5mol/n-hexane solution to approx.
The reaction was carried out for 15 minutes to obtain a solution of the first catalyst component. Take 10 ml of the first catalyst component solution, add 6.2 g of butyl acrylate and 0.02 g of azobisisobutyronitrile, and add distilled water bubbled with nitrogen gas (hereinafter referred to as " _N2 bubbling water"). ) to 100 ml with 3.6 g of sodium lauryl sulfate, and heated with an ultrasonic homogenizer (ultrasonic output 300 W, ultrasonic frequency 19 k) under a nitrogen gas atmosphere.
An aqueous dispersion was prepared by finely dispersing the particles so that the particle size of the dispersed particles was 0.05 to 0.2 μm. This will be referred to as "dispersion 1". Pour 80ml of _N2 bubbling water into a 300ml pressure bottle and seal it in advance, and add Dispersion 1 to it.
23.6 ml of was added and cooled in ice water for 10 minutes. After adding 6.2 g of 1,3-butadiene and shaking gently by hand, carbon disulfide was added as the second catalyst component.
Add 1 ml of 0.1 mol/n-hexane solution,
The container was shaken for 2 hours at room temperature of 20°C. Next, this container was shaken for 5 hours in a thermostatic water bath controlled at 75°C to obtain an aqueous dispersion of the graft copolymer. Example 2 After putting 7.5 ml of an n-hexane solution of 0.2 mol of cobalt octylic acid in a pressure bottle with a capacity of 100 ml, which had been purged with nitrogen in advance, a magnetic rotor was put in the bottle.
I corked it. 1,3-butadiene 2.6ml (room temperature 20℃)
was added, and the magnetic rotor was rotated vigorously while cooling in ice for 10 minutes. Sodium boron hydride 1.0mol/Tso-propanol solution 22.5
ml was added and reacted for about 15 minutes to obtain a solution of the first catalyst component. Mix 10.9 ml of this first catalyst component solution with 31 g of butyl acrylate and 0.1 g of azobisisobutyronitrile, and add _N2 bubbling water.
An aqueous dispersion was prepared by adding 8.0 g of sodium lauryl sulfate to 100 ml and finely dispersing the dispersed particles with an ultrasonic homogenizer under a nitrogen gas atmosphere so that the particle size of the dispersed particles was 0.05 to 0.2 μm. This will be referred to as "dispersion 2". Pour 80ml of _N2 bubbling water into a 300ml pressure bottle and seal it in advance, and add Dispersion 2 to it.
Add 30ml and cool in ice water for 10 minutes, add 1,3
- After adding 6.2 g of butadiene and shaking gently by hand, add carbon disulfide as the second catalyst component.
Add 1 ml of 0.1 mol/n-hexane solution,
The container was shaken for 2 hours at room temperature of 20°C. Next, the container
The mixture was shaken for 5 hours in a thermostatic water bath controlled at 75°C to obtain an aqueous dispersion of the graft copolymer. Example 3 A solution of the first catalyst component was prepared in the same manner as in Example 2. Bubble 10.9 ml of this catalyst component solution with _N2 water.
An aqueous dispersion was prepared by adding 2.0 g of sodium lauryl sulfate to 100 ml and finely dispersing the dispersed particles with an ultrasonic homogenizer under a nitrogen gas atmosphere so that the particle size of the dispersed particles was 0.05 to 0.2 μm. This will be referred to as "dispersion 3". Pour 80ml of _N2 bubbling water into a 300ml pressure bottle and seal it in advance, and add Dispersion 3 to it.
22 ml of was added and cooled in ice water for 10 minutes. Add 6.2 g of 1,3-butadiene to this, shake lightly by hand, and add carbon disulfide as the second catalyst component.
Add 1 ml of 0.1 mol/n-hexane solution
The first stage polymerization was carried out by shaking the container at 20°C for 2 hours. Next, 40 g of 2-ethylhexyl acrylate,
5g n-hexane, benzoyl peroxide
Sodium lauryl sulfate 2.0g in 40ml distilled water
g, and while cooling with ice water, use an ultrasonic homogenizer to reduce the particle size of the dispersed particles to 0.05~
An aqueous dispersion was prepared by finely dispersing the particles to a particle size of 0.2 μm. This will be referred to as "Dispersion 4". 13g of this dispersion 4 was dispersed and added to a pressure bottle containing the dispersion obtained in the first stage polymerization, and after shaking at room temperature for 1 hour, it was placed in a constant temperature water bath with a temperature controlled at 75℃. The mixture was transferred to a microwave oven and shaken for 5 hours to carry out the second stage of polymerization, thereby obtaining an aqueous dispersion of a graft copolymer. Example 4 The first stage of polymerization was carried out in the same manner as in Example 3, and then 0.3 g of methacrylic acid and 1 ml of a 0.1% sodium persulfate aqueous solution were added, and the mixture was shaken for 5 hours in a thermostatic water bath controlled at 75°C. A second stage of polymerization was carried out to obtain an aqueous dispersion of a graft copolymer. The electrical conductivity dropping point of the obtained graft copolymer revealed that 70% of the added methacrylic acid was polymerized on the particle surface. Example 5 7.5 ml of a solution of 0.2 mol of cobalt octylic acid in n-hexane was poured into a 500 ml pressure bottle that had been purged with nitrogen in advance, and then 110 ml of cyclohexane was added.
, then a magnetic rotor was inserted and the cap was capped. 1,3-
After adding 26 ml of butadiene (room temperature 20°C), in ice
The magnetic rotor was rotated vigorously while cooling for 20 minutes. Add 60 ml of n-hexane solution containing 0.5 mol of butyl lithium to this and let it react for about 30 minutes.
A solution of catalyst components was obtained. To this catalyst component solution, 37.2 g of methyl methacrylate, 37.2 g of butyl acrylate, and 0.12 g of azobisisobutyronitrile were added, and this was added to 600 ml of distilled water that had been added with 26 g of sodium lauryl sulfate and bubbled with nitrogen. After preliminary dispersion using a homomixer in a gas atmosphere, the mixture was emulsified and dispersed using a homogenizer (Model 15M manufactured by Manton Gaulin) to prepare an aqueous dispersion in which the dispersed particles had a particle size of 0.05 to 0.1 μm. This will be referred to as "dispersion 5". Put 2.4 ml of N ₂ bubbling water into the pressure-resistant polymerization container in step 5, add dispersion 5 to it, and add 186 g of 1,3-butadiene while controlling the temperature at 5°C.
was added and stirred vigorously for 15 minutes. To this was added 5 ml of a methyl acetate solution containing 0.6 mol of carbon disulfide, which is the second catalyst component, and polymerization was carried out with gentle stirring for 2 hours while controlling the temperature at 15°C. Next, the temperature of the polymerization vessel was controlled at 75℃,
The reaction was carried out for 5 hours with gentle stirring to obtain an aqueous dispersion of a graft copolymer. Example 6 A solution of the first catalyst component was prepared in the same manner as in Example 5. This catalyst component solution and 12 g of sodium lauryl sulfate were added to 600 ml of _N2 bubbling water, predispersed using a homomixer under a nitrogen gas atmosphere, and then emulsified and dispersed using a homogenizer.
An aqueous dispersion with dispersed particles having a particle size of 0.05 to 0.1 μm was prepared. This will be referred to as "dispersion 6". 186 g of commercially available styrene-butadiene copolymer latex "#0599" (manufactured by Nippon Gosei Rubber Co., Ltd., average particle diameter of dispersed particles 0.1 μm) obtained by emulsion polymerization was taken in terms of solid content, and distilled water was added. Dilute with water volume 2.4
This was placed in a pressure-resistant polymerization container with a capacity of 5, and after bubbling nitrogen for 30 minutes, dispersion 6 was added thereto and the temperature was controlled at 5°C for 30 minutes.
Stir vigorously for a minute. Then 1,3-butadiene
After adding 186 g and stirring vigorously for 15 minutes, 5 ml of n-hexane solution containing 0.6 mol of carbon disulfide, which is the second catalyst component, was added, and polymerization was carried out with gentle stirring for 2 hours while controlling the temperature at 15°C. . Next, 10 ml of a 5% aqueous solution of sodium persulfate was added and the temperature was raised to 75°C. When the temperature reached 75°C, 66 g of styrene, 37 g of methyl methacrylate, and 74 g of 2-ethylhexyl acrylate were added to the system in advance.
g, 9 g of methacrylic acid, 0.5 g of sodium dodecylbenzenesulfonate and nonionic soap ("EM").
-931" (manufactured by Kao Soap Co., Ltd.); nonylphenol ethoxylated with 28 moles of ethylene oxide per 1 mole of nonylphenol) and 190 g of distilled water.
An emulsion obtained by emulsifying the solution in g was gradually added over a period of 3 hours to carry out polymerization. Regarding the aqueous dispersions and polymers of the polymers obtained in Examples 1 to 3, Examples 5 and 6 above, the following items were investigated. (1) Polymerization yield (2) Solid content percentage of aqueous dispersion (3) Average particle size of polymer particles (by dynamic light scattering method), (4) Melting point of polymer (by differential scanning calorimetry), (5) Content ratio of vinyl groups in the polymer (according to Morero analysis method of infrared absorption spectrum); (6) Grafting efficiency determined by the following method (for Example 1; other cases follow the same). After recovering the polymer from the aqueous dispersion and drying it, 10 g of it is collected. The amount of polymerized butyl acrylate component in 10 g of polymer is determined from the charging composition and polymerization conversion rate, and this is defined as W ₁ . 10 g of the polymer was extracted with water for 20 hours using tetrahydrofuran as a solvent, and the amount of butyl acrylate polymer extracted was determined, and this was designated as _W2 . The butyl acrylate polymer component W ₃ grafted onto the polymer is determined from the formula W ₃ =W ₁ −W ₂ . Grafting efficiency (%) = W ₃ /W ₁ ×100 It should be noted that the higher the grafting efficiency, the more monomers are grafted onto the conjugated diene polymer. The above results are shown in Table 1.

【table】

【table】

Claims (1)

[Scope of Claims] 1. A method for producing an aqueous dispersion of a polymer, which comprises carrying out the following first and second stage polymerization steps in an aqueous dispersion medium. 1st stage: (A) a cobalt compound and (B) an organometallic compound or hydride of a metal from Groups 1 to 3 of the periodic table, at a ratio of 1 to 1000 to the cobalt compound (A).
The first catalyst component obtained by contacting in the presence of twice the molar amount of conjugated diene monomer is dispersed in an aqueous dispersion medium, and then the conjugated diene monomer and (C) carbon disulfide, phenyl isothiocyanic acid and a second catalyst component consisting of at least one compound selected from the group of xanthogen compounds, and the conjugated diene monomer is polymerized, so that the conjugated diene monomer has 70% or more of unsaturated hydrocarbon groups in the side chain. A polymerization process to obtain an aqueous dispersion of a conjugated diene polymer. Second stage: In the presence of the polymer obtained in the first stage, by reacting a conjugated diene monomer and/or other polymerizable monomers, these monomers are added to the polymer. Polymerization process for grafting.