JPH11349607A - Seed particle, vinyl polymer and their preparation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a seed particle which has polar groups on its surface and therefore has a good dispersibility in a reaction medium such as water, or the like, and yields a vinyl polymer having a good dispersibility. SOLUTION: A seed particle having an average particle size of from 0.05 to 15 μm has at least two polar groups selected from the group consisting of carboxyl group, a sulfonate group, a phosphate group, an amide group and hydroxyl group on its surface. This seed particle is formed by using a monomer having polar groups and/or a reaction initiator which forms polar groups. Use of a seed particle formed thereby in seed polymerization reduces the amount of dispersant to be used, as compared to the conventional process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to self-dispersing seed particles, a method for producing the same, a method for producing a vinyl polymer using the seed particles, and a vinyl polymer obtained by the method.

[0002]

BACKGROUND OF THE INVENTION In a method for producing a vinyl polymer, a method of producing seed particles in advance and dispersing the seed particles in an aqueous medium containing a vinyl monomer to carry out polymerization is known as seed polymerization. Have been. In this seed polymerization, it was necessary to use a large amount of a dispersant (or emulsifier) in order to stably disperse the seed particles and the vinyl monomer component to be polymerized in an aqueous medium. In particular, the seed particles usually have a constant particle size, and in order to stably disperse such seed particles in an aqueous medium, it is necessary to use a large amount of a dispersant or emulsifier.

[0003] The dispersant or emulsifier used here is a kind of surfactant, and when such a dispersant or emulsifier is used in a large amount, the dispersant or emulsifier remains in the obtained vinyl polymer, The remaining dispersant or emulsifier has a significant effect on the properties of the resulting vinyl polymer. In particular, since such a dispersant or emulsifier is a kind of surfactant, it has a significant effect on the water resistance, weather resistance and transparency of the obtained vinyl polymer.

[0004] Such a dispersant or emulsifier can be removed after the production of the vinyl polymer. However, in order to remove such a dispersant or emulsifier, a plurality of steps and a large amount of solvent are required. However, such a method is not suitable as an industrial method.

[0005] The present inventor has argued that unlike conventional seed particles which are difficult to stably disperse in an aqueous medium without a dispersant or an emulsifier, seed particles having a specific particle size having a specific polar group on the surface are self-dispersing. When the vinyl polymer is polymerized by dispersing the seed particles having such self-dispersibility and a vinyl monomer in an aqueous medium, the seed particles absorb the vinyl monomer and polymerize so as to expand. Progressed, and the present invention was completed based on the finding that the above-mentioned specific polar group was present on the surface of the grown particles and that the grown particles were also stably dispersed in the aqueous medium.

[0006]

That is, the present invention has been made in view of such technical background, and an object of the present invention is to provide novel seed particles having better dispersion stability than conventional seed particles.

The present invention provides a method for producing the seed particles, a method for producing a vinyl polymer using the seed particles thus produced, and a vinyl polymer produced in this manner. It is an object.

[0008]

SUMMARY OF THE INVENTION According to the present invention, an average particle size of at least two polar groups selected from the group consisting of a carboxyl group, a sulfonate group, a phosphoric acid group, an amide group and a hydroxyl group is present on the surface. Provide 15 μm seed particles.

[0009] The seed particles of the present invention comprise a monomer containing, in an aqueous medium, a polar group-containing monomer having at least one type of polar group selected from the group consisting of a carboxyl group, a sulfonate group, a phosphoric acid group, an amide group and a hydroxyl group. Dispersing a component and a reaction initiator having at least one kind of polar group selected from the group consisting of a carboxyl group, a sulfonate group, a phosphoric acid group, an amide group and a hydroxyl group and / or a reaction initiator capable of forming these groups It can be produced by polymerizing. However, the polar group of the polar group-containing monomer and the polar group from the reaction initiator are combined in at least two types.

The vinyl polymer of the present invention comprises, in an aqueous medium, a polar group-containing monomer having at least one type of polar group selected from the group consisting of a carboxyl group, a sulfonate group, a phosphoric acid group, an amide group and a hydroxyl group. Dispersing a monomer component and a reaction initiator having at least one kind of polar group selected from the group consisting of a carboxyl group, a sulfonate group, a phosphoric acid group, an amide group and a hydroxyl group and / or a reaction initiator capable of forming these groups And polymerized to have an average particle diameter of at least two types of polar groups of 0.1.
At least a step of obtaining seed particles of 0.5 to 15 μm, and a step of adding a vinyl monomer to an aqueous medium in which the seed particles obtained in the above step are dispersed, and performing (co) polymerization while taking in the vinyl monomer. It is manufactured through a polymerization step.

The seed particles of the present invention have a specific polar group on the surface and a specific particle size, and the seed particles are stably dispersed in an aqueous medium. The polar groups present on the surface of the seed particles include a polar group derived from a monomer and a polar group derived from a polymerization initiator. By using the seed particles having a polar group as described above, since the seed particles self-disperse in an aqueous medium, a dispersant (emulsifier) for dispersing the seed particles is actively used by using the seed particles. Dispersed in aqueous medium without using,
Polymerization is performed while absorbing vinyl monomers into the seed particles to produce a vinyl polymer.

The vinyl-based polymer is produced by polymerizing the seed particles so that the seed particles grow while absorbing the vinyl-based monomer, and the surface of the resulting vinyl-based polymer particles still has a polar group. Present and the resulting polymer particles are stably dispersed in the aqueous medium.

Therefore, the vinyl polymer of the present invention has a very small content of a dispersant (emulsifier), and this vinyl polymer is excellent in water resistance, weather resistance and transparency.

[0014]

DETAILED DESCRIPTION OF THE INVENTION Next, the seed particles of the present invention, a method for producing the same, a method for producing a vinyl polymer using the seed particles, and the vinyl polymer thus obtained will be described.
A specific description will be given along the manufacturing method.

The seed particles having a polar group on the surface used in the present invention include a (meth) acrylate and a copolymer which is copolymerizable with the (meth) acrylate and has a polar group. A copolymer having styrene monomers such as styrene, methyl styrene, etc. copolymerized by dispersing and polymerizing other monomers in water as required, and styrene monomers such as styrene monomers, and a polar group And a vinyl ester-based monomer such as vinyl acetate, vinyl propionate, or the like, which is obtained by dispersing and polymerizing a monomer having, if necessary, another monomer in water, and copolymerizing with the vinyl ester-based monomer. Copolymer obtained by dispersing and polymerizing a monomer having a polar group and, if necessary, another monomer in water, vinyl chloride A halogen-containing monomer such as vinylidene chloride, and a copolymer which is copolymerizable with the halogen-containing monomer and has a polar group and, if necessary, another monomer dispersed and polymerized in water. Can be mentioned. However, the polymer is not prompted by the above-mentioned monomer group and may be any polymer into which a carboxyl group, a sulfonate group, or the like can be introduced. In particular, in the present invention, a (meth) acrylate, a monomer having a polar group copolymerizable with the (meth) acrylate and, if necessary, another monomer are dispersed in water and polymerized. Copolymers are preferred.

Examples of such (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (Meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decanyl (meth) acrylate, undecanyl (meth) acrylate, dodecanyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and isononyl Examples thereof include (meth) acrylate, methoxyethyl (meth) acrylate, and ethoxyethyl (meth) acrylate.

The monomer which is copolymerizable with the (meth) acrylic acid ester and has a polar group has at least one of a carboxyl group, a sulfonate group, a phosphoric acid group, a phosphoric acid group, an amide group and a hydroxyl group as a polar group. Compounds having an ethylenic double bond copolymerizable with the (meth) acrylate are preferred. Examples of such polar group-containing monomers include (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, t-butylacrylamide sulfonic acid, styrene sulfonic acid, 2-sulfoxyethyl (meth) acrylate, and (meth) ) Allylsulfonic acid,
(Meth) acrylic acid amide, dimethylamide (meth)
Acrylate, 2-hydroxyethyl (meth) acrylate or a salt thereof can be exemplified.

It is necessary that a polar group is present on the surface of the seed particles used in the present invention. When the polar group is derived from the monomer containing the polar group, the polar group may be present. As the group-containing monomer, acrylic acid, methacrylic acid, t-butylacrylamide sulfonic acid and the like are preferable.

Further, the seed particles used in the present invention may be crosslinked by copolymerizing other monomers such as ethylene glycol di (meth) acrylate, divinylbenzene and the like.

The seed particles used in the present invention can be obtained by dispersing the above-mentioned monomers in an aqueous medium and copolymerizing them. When dispersing the above monomer in the aqueous medium, the monomer can be finely dispersed in the aqueous medium by forced mechanical mixing, but a surfactant can be used as an emulsifier, and further, a water-soluble polymer Can also be used. Here, examples of the surfactant used as the emulsifier include an anionic surfactant, a nonionic surfactant, a cationic surfactant, and a reactive surfactant. In particular, in the present invention, it is preferable to use an anionic surfactant and / or a reactive surfactant. Here, the reactive surfactant has a hydrophilic group and a lipophilic group, and has a reactive group,
Before the reaction, it acts as an emulsifier for dispersing monomers and the like in an aqueous medium, and as the reaction proceeds, this reactive emulsifier acts as a monomer and reacts with other monomers to form seed particles, and at the same time, forms a polar group. In some cases.

In producing the seed particles, a reaction initiator is used. In the present invention, it is necessary that a polar group is present on the surface of the seed particles.
There are cases where it is derived from the above-mentioned monomer containing a polar group and cases where it is derived from a reaction initiator. Examples of the initiator used to cause the polar group derived from the initiator to be present on the surface of the seed particles include, for example, potassium persulfate, ammonium persulfate, 4,4′-azobis-4-cyanovaleric acid,
2'-azobis (2-methylpropionamidine) dihydrochloride, 2,2'-azobis (2-methyl-N- (2-hydroxyethyl) propionamide, etc. can be used. Among these, the sulfonate group is seeded. When present on the surface of the particles, potassium persulfate as a reaction initiator,
It is preferred to use ammonium persulfate. Further, when a persulfate is used as the reaction initiator, a reducing agent such as sodium thiosulfate may be used in combination.

After finely dispersing the above monomer and reaction initiator in an aqueous medium, emulsion polymerization is carried out by a conventional method to produce seed particles. In order for the seed particles to have a polar group on the surface so as to have self-dispersibility, a vinyl monomer having no polar group is usually used in an amount of 80 to 99.9 parts by weight, preferably 92 to 98 parts by weight.
Parts by weight, the polar group-containing monomer is usually used in an amount of 0.1 to 20 parts by weight, preferably 2 to 8 parts by weight. It is used in an amount of 0.05 to 3 parts by weight, preferably 0.1 to 0.5 parts by weight.

When the seed particles are produced, the compounding weight ratio of the base monomer forming the seed particles such as (meth) acrylate or styrene to the polar group-containing monomer is about 99.9: 0.1 to 80. : 20 makes it possible to produce seed particles having high dispersion stability in an aqueous medium. Furthermore, when using a surfactant which is a dispersant or an emulsifier, it is preferable to use the same in an amount as small as possible. Preferably 0.01 to 1 part by weight, particularly preferably 0.1 to 1 part by weight.
It is used in an amount of from 0.01 to 0.5 parts by weight. However, since the reactive surfactant (reactive emulsifier) is taken into the seed particles after the reaction and hardly functions as a surfactant, it can be used in a larger amount than a normal emulsifier. The reactive emulsifier can be used in combination with another emulsifier.

The average particle size of the seed particles thus obtained must be in the range of 0.05 to 15 μm, preferably in the range of 0.2 to 10 μm, and more preferably in the range of 0.3 to 5 μm. It is particularly preferable that the ratio is in the range of

Although the seed particles are fine particles as described above, since the surface has a polar group, they are stably dispersed in an aqueous medium. Usually, the content (nonvolatile content) of the seed particles in this aqueous medium is 40 to 70% by weight.
Adjusted to the extent.

When the seed particles are produced in this manner, the polar group derived from the polar group-containing monomer or the polar group derived from the reaction initiator is unevenly distributed on the surface of the seed particles (that is, the polar group of the seed particles is more concentrated than the central part). Due to the high polar group content near the surface), the polar group ensures that the seed particles have good affinity for the aqueous medium and ensures dispersion stability of the seed particles in the aqueous medium.

The thus-obtained emulsion containing seed particles can be used as it is in the next step. Alternatively, the emulsion containing the seed particles thus obtained is added with an aqueous medium and the concentration is adjusted. Or the seed particles can be further separated and purified if necessary, and then redispersed in a new aqueous medium for use.

Next, in the present invention, a vinyl monomer is dispersed in the emulsion containing the seed particles obtained as described above. Examples of the vinyl monomer used herein include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate,
Pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate,
Decanyl (meth) acrylate, undecanyl (meth)
Acrylate, dodecanyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate, (meth) acrylic acid, itaconic acid,
Maleic acid, fumaric acid, 2-hydroxyethyl (meth) acrylate, (meth) acrylic amide, dimethylamide methacrylate, dimethylamide acrylate,
Like stearyl (meth) acrylate, behenyl (meth) acrylate, acrylamide, N-methylol acrylamide, acrylonitrile, glycidyl methacrylate, isobutyl (meth) acrylate, isobornyl (meth) acrylate and dicyclopentanyl (meth) acrylate Acrylic monomers, fluorine-containing monomers such as vinyl acetate, styrene, divinylbenzene, ethylene, crotonic acid, vinyl propionate, α-methylstyrene, vinyl chloride, vinylidene chloride, heptadecafluorodecyl (meth) acrylate, γ-methacrylic Silicon-containing monomers such as roxypropyltriethoxysilane can be exemplified.

In the present invention, a reaction initiator is used when the vinyl monomer is blended with the emulsion containing the seed particles for polymerization. In the present invention, it is preferable to use a peroxide or an azo compound as the reaction initiator. Examples of peroxides used here include:
Examples thereof include potassium persulfate, ammonium persulfate, benzoyl peroxide, lauroyl peroxide, and dialkyl perester. Examples of the azo compound used include 4,4′-azobis-4-cyanovaleric acid and 2,2′-azobisisobutyronitrile.

In the present invention, the vinyl monomer to be added to the seed particles having a polar group on the surface is usually added in an amount within the range of 20 to 5000 parts by weight based on 100 parts by weight of the seed particles. Further, the reaction initiator is 0.01 to 5 parts by weight based on 100 parts by weight of the vinyl monomer,
It is preferably incorporated in an amount of 0.1 to 2 parts by weight.

In the present invention, the above-mentioned vinyl monomer and the reaction initiator are dispersed in water, and then this dispersion is blended with an emulsion containing seed particles having a polar group on the surface and polymerized. However, the vinyl monomer and the reaction initiator are dispersed in water by forced stirring without using an emulsifier, or emulsification is performed by adding a trace amount of an emulsifier. When an emulsifier is used, the amount of the emulsifier in the obtained vinyl polymer of the present invention is usually 2% by weight or less, preferably 1% by weight or less, more preferably 0.9% by weight or less. , Particularly preferably 0.1.
It is used in an amount of less than 5% by weight, optimally less than 0.3% by weight. When using an emulsifier,
The emulsifier used here is not particularly limited, and can be appropriately selected from an anionic emulsifier and a nonionic emulsifier so as to have an HLB value capable of emulsifying the mixture of the vinyl monomer and the reaction initiator. . Further, as the emulsifier used here, the above-mentioned reactive emulsifier can also be used. Since the reactive emulsifier hardly functions as an emulsifier after the reaction, when the reactive emulsifier is used, the water resistance of the obtained vinyl polymer hardly decreases even if the reactive emulsifier is used more than the above value.

The reason why the amount of the emulsifier is small in the present invention is that the self-dispersing seed particles are used as a starting material. By using such self-dispersible seed particles and performing polymerization without using a very small amount of an emulsifier or without using an emulsifier, the vinyl polymer of the present invention has a remarkably excellent water resistance. , Weather resistance and transparency.

As the polymerization method of the above-mentioned components, a method usually employed in the production of a vinyl resin can be used. The above-mentioned raw materials are charged into a reactor, and the air in the reaction system is converted into a gas such as nitrogen gas. After the replacement with the inert gas, the reaction solution can be heated to a temperature of about 50 to 100 ° C. and reacted for a reaction time of 1 to 10 hours.

With such a reaction, the vinyl monomer is absorbed by the seed particles, and the seed particles react so as to expand. Usually, the vinyl-based monomer is reacted in an amount of 20 to 5,000 parts by weight with respect to 100 parts by weight of the seed particles. The vinyl polymer thus obtained is
Usually, it has an average particle size in the range of 0.1 to 35 μm.

The vinyl polymer thus produced can be used in the same manner as ordinary vinyl resins. The content of the emulsifier in the vinyl polymer of the present invention is at most 2% by weight, and it can be stably polymerized with about 1/10 or less of the emulsifier as compared with those produced in a conventional aqueous medium. The water resistance and the like of the vinyl polymer are often affected by a hydrophilic substance such as an emulsifier contained in the resin, rather than by the structure of the resin itself. Since the content of the emulsifier is 2% by weight or less as in the vinyl polymer of the present invention, the water resistance, weather resistance and transparency of the emulsifier hardly decrease.

[0036]

The vinyl polymer of the present invention exhibits excellent water resistance, weather resistance and transparency since the emulsifier contained therein is extremely small.

The content of the emulsifier can be reduced as described above because seed particles having a specific average particle diameter having a polar group on the surface so as to have self-dispersibility are used as a starting material. However, the use of seed particles having no polar group on the surface as in the past or the use of seed particles that deviate from the average particle size of the seed particles specified in the present invention results in a large amount of emulsification of the vinyl monomer. To require an emulsifier or affect the stability during polymerization,
It is not possible to produce a vinyl polymer having excellent water resistance, weather resistance and transparency as in the present invention.

As described above, since the vinyl polymer of the present invention is excellent in water resistance, weather resistance and transparency, it is suitable for applications such as pressure-sensitive adhesives, adhesives, paint additives, spacers and various matting agents. It can be suitably used.

[0039]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples of the present invention, but the present invention should not be construed as being limited thereto.

[0040]

Example 1 Synthesis Example of Seed Polymer A 360 g of water and 3.6 g of potassium persulfate were weighed and charged in a two-liter four-neck flask. The mouth of the four-necked flask is provided with a Dim funnel, a thermometer, a nitrogen gas blowing tube, and a dropping funnel.

Nitrogen gas was introduced from the nitrogen gas inlet tube of the four-necked flask, and the air in the container was replaced with nitrogen gas and purged. In another container, weigh 300 g of water,
6 g of sodium dodecylbenzenesulfonate as an emulsifier is added to and dissolved in the water, and 24 g of acrylic acid, tert-butylacrylamide sulfonic acid (trade name: TBAS-Q), manufactured by Nitto Chemical Industry Co., Ltd.) 24
g, acrylonitrile 36 g, butyl acrylate 111
A monomer emulsion was prepared by adding 6 g and 0.5 g of n-dodecyl mercaptan.

The temperature of the previously measured reaction liquid in the four-necked flask was raised to 75 ° C., and the monomer emulsion prepared as described above was added dropwise over 3 hours.
The temperature was raised to ° C. to carry out a polymerization reaction.

The resulting emulsion A had a nonvolatile content of 6
2.2% by weight, the average particle diameter of the obtained seed polymer A particles was 0.52 μm. In addition, this emulsion A
Was 0.5 part by weight with respect to 100 parts by weight of the seed polymer.

On the surface of the seed polymer A, there were a carboxyl group and a sulfonate group derived from a monomer, and a sulfonate group derived from a polymerization initiator.

[0045]

Example 2 Synthesis Example of Seed Polymer B In a two-liter four-necked flask, 360 g of water and 3.6 g of potassium persulfate were weighed and charged. The mouth of the four-necked flask is provided with a Dim funnel, a thermometer, a nitrogen gas blowing tube, and a dropping funnel.

Nitrogen gas was introduced from the nitrogen gas inlet tube of the four-necked flask, and the air in the container was replaced with nitrogen gas and purged. In another container, weigh 300 g of water,
6 g of sodium dodecylbenzenesulfonate was added as an emulsifier to this water to dissolve it, and then 24 g of acrylic acid, 24 g of acrylamide, and
A monomer emulsion was prepared by adding 6 g, 1116 g of butyl acrylate, and 0.5 g of n-dodecyl mercaptan.

The temperature of the reaction solution in the four-necked flask, which was measured in advance, was raised to 75 ° C., and the monomer emulsion prepared as described above was added dropwise over 3 hours.
The temperature was raised to ° C. to carry out a polymerization reaction.

The resulting emulsion B had a nonvolatile content of 6
2.5% by weight, the average particle size of the particles was 0.59 μm. The amount of the emulsifier contained in this emulsion B was 0.5 part by weight based on 100 parts by weight of the seed polymer.

On the surface of the seed polymer B, there were a carboxyl group and an amide group derived from a monomer, and a sulfonate group derived from a polymerization initiator.

[0050]

Example 3 Synthesis Example of Seed Polymer C In a two-liter four-necked flask, 360 g of water and 3.6 g of potassium persulfate were weighed and charged. The mouth of the four-necked flask is provided with a Dim funnel, a thermometer, a nitrogen gas blowing tube, and a dropping funnel.

Nitrogen gas was introduced from the nitrogen gas inlet tube of the four-necked flask, and the air in the container was replaced with nitrogen gas and purged. In another container, weigh 300 g of water,
6 g of sodium dodecylbenzenesulfonate as an emulsifier was added to and dissolved in this water, and a monomer emulsion was prepared by adding 48 g of acrylic acid, 36 g of acrylonitrile, 1116 g of butyl acrylate, and 0.5 g of n-dodecylmercaptan to this solution. did.

The temperature of the previously measured reaction solution in the four-necked flask was raised to 75 ° C., and the monomer emulsion prepared as described above was added dropwise over 3 hours.
The temperature was raised to ° C. to carry out a polymerization reaction.

The emulsion C obtained had a nonvolatile content of 6
2.8% by weight, the average particle size of the particles was 0.68 μm. The amount of the emulsifier contained in the emulsion C was 0.5 part by weight based on 100 parts by weight of the seed polymer.

On the surface of the seed polymer C, there were a carboxyl group derived from a monomer and a sulfonate group derived from a polymerization initiator.

[0055]

Example 4 A polymerization reaction was carried out in the same manner as in Example 1, except that the composition of the monomer emulsion was changed to 24 g of acrylic acid, 24 g of 2-hydroxyethyl acrylate, 36 g of acrylonitrile, and 1116 g of butyl acrylate.

The emulsion D obtained had a nonvolatile content of 6
2.4% by weight, the average particle size of the particles was 0.73 μm. On the surface of the seed particles D, there were a carboxyl group and a hydroxyl group derived from the monomer, and a sulfonate group derived from the polymerization initiator.

[0057]

Example 5 In Example 1, the composition of the monomer emulsion was changed to acid phosphooxyethyl methacrylate 48.
g, acrylonitrile 36 g, butyl acrylate 111
A polymerization reaction was carried out in the same manner except that the amount was 6 g.

The emulsion E obtained had a nonvolatile content of 6
2.9% by weight, the average particle size of the particles was 0.71 μm. On the surface of the seed particles E, a phosphate group derived from a monomer and a sulfonate group derived from a polymerization initiator were present.

[0059]

Comparative Example 1 A polymerization reaction was carried out in the same manner as in Example 1 except that the composition of the monomer emulsion was changed to 1,200 g of butyl acrylate. It has become possible.

[0060]

Comparative Example 2 A polymerization reaction was carried out in the same manner as in Example 1 except that the composition of the monomer emulsion was changed to 1200 g of butyl acrylate and 24 g of sodium dodecylbenzenesulfonate.

The emulsion F obtained had a nonvolatile content of 6
3.5% by weight, the average particle size of the particles was 0.61 μm. A sulfonate group derived from the polymerization initiator was present on the surface of the seed particles F.

[0062]

Example 6 The seed particle dispersion (emulsion A) 24 obtained in Example 1 was placed in a flask having a capacity of 2 liters.
0 g and 50 g of water were charged, 5 g of benzoyl peroxide was added as a reaction initiator, and the mixture was stirred for 30 minutes while replacing the air in the reactor with nitrogen gas.

Separately, isobutyl acrylate 81
6 g, 34 g of acrylic and 0.5 g of t-dodecyl mercaptan as a chain transfer agent were dissolved therein, and 300 g of water and 2.5 g of sodium dodecylbenzenesulfonate were further added thereto.
g was added and stirred to prepare an emulsion.

The emulsion thus obtained was charged into the flask, and the air in the flask was replaced with nitrogen gas while stirring for further 30 minutes. Thereafter, the reaction solution was heated to 72 ° C. and kept at this temperature for 5 hours. Thus, the vinyl polymer of the present invention was produced. The polymerization stability, the degree of polymerization, the average particle size, and the amount of the emulsifier contained in the obtained vinyl polymer are shown below.

In the present invention, the polymerization stability was determined by calculating the amount of agglomerates on a wire mesh when 1 kg of the obtained emulsion was filtered through a 200 mesh wire mesh.

[0066]

(Equation 1)

[0067]

Examples 7 to 12 and Comparative Example 3 A vinyl polymer was produced in the same manner as in Example 6, except that the types and amounts of the seed particle dispersion and the monomers were as shown in Table 1 below.

[0068]

[Table 1]

Claims (7)

[Claims] 1. A seed particle having an average particle diameter of 0.05 to 15 μm having at least two types of polar groups selected from the group consisting of a carboxyl group, a sulfonate group, a phosphoric acid group, an amide group and a hydroxyl group on the surface. . 2. A monomer component containing a polar group-containing monomer having at least one type of polar group selected from the group consisting of a carboxyl group, a sulfonate group, a phosphoric acid group, an amide group and a hydroxyl group in an aqueous medium; It is characterized in that a polymerization initiator having at least one kind of polar group selected from the group consisting of a sulfonate group, a phosphoric acid group, an amide group and a hydroxyl group and / or a polymerization initiator capable of forming these groups is dispersed and polymerized. The average particle size of at least two types of polar groups on the surface is set to 0.1.
A method for producing seed particles having a size of from 0.5 to 15 μm. 3. The production of seed particles according to claim 2, wherein the aqueous medium further contains 0.01 to 2 parts by weight of a dispersant based on 100 parts by weight of the total of monomers. Method. 4. A monomer component other than the polar group-containing monomer that forms the seed particles, at least one selected from the group consisting of alkyl (meth) acrylate, styrene, methylstyrene, vinyl acetate, vinyl propionate and vinyl chloride. 3. The method for producing seed particles according to claim 2, wherein the vinyl monomer is a vinyl monomer. 5. Seed particles having an average particle diameter of 0.05 to 15 μm, on the surface of which at least two types of polar groups selected from the group consisting of a carboxyl group, a sulfonate group, a phosphoric acid group, an amide group and a hydroxyl group are present. A vinyl polymer obtained by seed (co) polymerization of a vinyl monomer using 6. A monomer component containing a polar group-containing monomer having at least one kind of polar group selected from the group consisting of a carboxyl group, a sulfonate group, a phosphoric acid group, an amide group and a hydroxyl group in an aqueous medium; A reaction initiator having at least one type of polar group selected from the group consisting of a sulfonate group, a phosphoric acid group, an amide group and a hydroxyl group and / or a reaction initiator capable of forming these groups is dispersed and polymerized on the surface. At least 2
A step of obtaining seed particles having an average particle diameter of 0.05 to 15 μm having various kinds of polar groups, adding a vinyl monomer to an aqueous medium in which the seed particles obtained in the above step are dispersed, and adding the vinyl monomer A method for producing a vinyl polymer, comprising at least a (co) polymerization step. 7. The method for producing a vinyl polymer according to claim 6, wherein the formed vinyl polymer is a particle having an average particle diameter of 0.1 to 35 μm.