JPH03196830A - Dispersant composition and production of dispersion of vinyl polymer with this composition - Google Patents

Abstract

PURPOSE:To increase the rate of polymn. of a vinyl monomer by dispersing or dissolving an amphoteric high molecular material contg. cationic groups and anionic groups in a medium under conditions under which the cationic groups dissociate and using the resulting dispersant compsn. CONSTITUTION:An amphoteric high molecular material contg. cationic groups such as amino groups and anionic groups, e.g. carboxyl groups is dispersed or dissolved in a medium under conditions under which the cationic groups dissociate to prepare a dispersion or soln. as a dispersant compsn. A vinyl monomer is polymerized in the dispersant compsn. and the anionic groups are dissociated to produce a dispersion of a vinyl polymer capable of forming a heat resistant and highly glossy coating film and useful as a binder for paint and printing ink, various surface processing agents, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a dispersant composition and a method for producing a vinyl polymer dispersion using the composition.

[Prior Art] Polymer dispersions containing polymer components as dispersoids are used in many fields, such as as binders in paints and inks, and as surface finishing agents or treating agents for various wood materials.

Polymer dispersions are dilutable with water, or so-called aqueous dispersions whose dispersion medium is water or a mixture of water and an organic solvent are close to each other due to their low pollution and resource saving properties. The demand for higher quality is increasing from time to time.

Therefore, a method for producing a polymer dispersion that has both gloss and anti-blocking properties is developed by emulsion polymerizing a polymerizable vinyl monomer in a water-alcohol mixed medium in the presence of a specific acrylic resin. Publication No. 60-37135) or an amine salt of a specific low molecular weight copolymer copolymerized with an unsaturated carboxylic acid. A method for producing a vehicle for printing ink (Japanese Patent Application Laid-Open No. 53-84 [191]) has been proposed.

In addition, the present inventors have previously proposed a method for producing a polymer dispersion having a high glass transition temperature and excellent film-forming properties (Jiko [463-221105]).

[Problem to be Solved by the Invention J] By the way, all of the prior art methods for producing polymer dispersions described above involve polymerizing vinyl monomers using an anionic polymer as a dispersant. According to such conventional methods, the polymerization rate tends to be very slow, and the resulting polymer dispersion has the drawbacks that the monomer is released deep inside and lacks stability. In order to overcome this drawback, disadvantages in industrial practice cannot be avoided, such as significantly extending the polymerization time, adding a polymerization initiator, etc., or post-treatment of the obtained polymer dispersion.

Means for Solving Problem E] In order to solve the above-mentioned problem, the present inventors conducted intensive research and found that the ionicity of the polymeric substance used as a dispersant and the vinyl monomer II to be polymerized were The present invention was completed based on this knowledge in view of the relationship with polymerizability. That is, the present invention is directed to the polymerization of vinyl monomers in the polymerization system as a dispersant when the polymeric substance present in the polymerization system as a dispersant is dispersed or dissolved in a medium as a polycation. If the polymer substance has both a cationic group and an anionic group, it will enter the polymerization system as a polycation under conditions in which the cationic group of the polymer substance dissociates. This is based on the finding that a similar effect is expressed when it is present.

The present invention provides a dispersant composition comprising a dispersion or solution in which an amphoteric polymeric substance containing a cationic group and an anionic group is dispersed or dissolved in a medium under conditions in which the cationic group dissociates. It also provides a dispersion or solution in which an amphoteric polymeric substance containing a cationic group and an anionic group is dispersed or dissolved in a medium under conditions that dissociate the cationic group. is a dispersant composition consisting of an F8 liquid, and a novel method for producing a dispersion of a vinyl polymer, which comprises polymerizing a vinyl monomer in the presence of the composition and then dissociating the anionic group. It provides:

The biological amphoteric polymer substance of the dispersant of the present invention has both a cationic group and an anionic group,
It can be dispersed or dissolved in the medium under conditions in which either one of the ionic groups dissociates, and those skilled in the art can easily determine the relationship between the content of the ionic groups and the medium composition. It's something you can imagine. Specifically, it is preferable that the medium is an alcohol having 1 to 4 carbon atoms, a polyhydric alcohol such as ethylene glycol or propylene glycol, a mixture of these with water, or a hydrophilic medium such as water. It is safe that the content of amphoteric groups in the amphoteric polymeric substance is about 20 milliequivalents or more per 100g of the polymeric substance.

Especially preferred amphoteric polymer! One type has a primary, secondary, or tertiary 7-amino group as a cationic group and a carboxyl group as an anionic group. Such amphoteric polymeric substances can be obtained or synthesized as natural polymers or modified products thereof, or by known methods such as vinyl polymerization, ring plate polymerization, or polyaddition reactions. The most preferred amphoteric polymer material is a multicomponent polymer obtained by copolymerizing a vinyl monomer having an amino group, a vinyl monomer having a carboxyl group, and other vinyl monomers that can be copolymerized with them. It is a polymer. Specific examples of vinyl monomers having an amino group include aminoalkyl acrylate monomers such as dimethylaminoethyl acrylate and diethylaminoethyl acrylate; aminoalkyl methacrylate monomers such as dimethylamine ethyl methacrylate and diethylaminoethyl methacrylate; Examples include aminoalkylacrylamide monomers such as dimethylaminopropylacrylamide, aminoalkylmethacrylamide monomers such as dimethylaminopropylmethacrylamide, vinyl compounds such as vinylpyridine and vinylimidazole, and allylamine compounds such as allylamine and diallylamine. be able to. These can be used alone or in combination of two or more. Particularly preferred is dimethylaminoethyl acrylate or dimethylaminoethyl methacrylate.

Specific examples of vinyl monomers having carboxyl groups include unsaturated carbonic acids such as acrylic acid, methacrylic acid, and crotonic acid; unsaturated polycarphonic acids such as maleic acid, maleic anhydride, fural acid, and itaconic acid; , and half esters thereof. These can be used alone or in combination of two or more. Acrylic acid or methacrylic acid is particularly preferred. Specific examples of other copolymerizable vinyl monomers include methyl acrylate, ethyl acrylate, 70-vinyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, stearyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, Phenyl acrylate Acrylic acid ester monomers such as benzyl acrylate, isobornyl acrylate, dicyclopentadienyl acrylenite, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate
Methacrylic acid ester monomers such as stearyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, phenyl methacrylate, pencil methacrylate, isobornyl methacrylate, dicyclopentagenyl methacrylate, acrylamide, N, N-dimethylacrylamide, N-t -7
Acrylamide monomers such as tylacrylamide, methacrylamide, N.

Methacrylamide monomers such as N-dimethylmethacrylamide and Nt-butylmethacrylamide, styrene,
Aromatic vinyl monomers such as α-methylstyrene, vinyltoluene, p-ethylstyrene, methoxystyrene, 2,4-dimethylstyrene, vinyl esters such as vinyl acetate or vinyl propionate, methyl vinyl ether or ethyl Examples include vinyl ethers such as vinyl ether and other olefin compounds. These can be used alone or in combination of two or more.

Particularly preferred are acrylic ester monomers, methacrylic ester monomers, and styrene.

In order to produce an amphoteric multicomponent copolymer by copolymerizing the vinyl monomers described above, 3 to 20% by weight of the vinyl monomer containing the above amino group, a vinyl monomer having a carboxyl group, 6-30% by weight of monomer and 50-30% of other copolymers
It can be synthesized by copolymerizing 91% by weight by radical synthesis using a conventional method. As the polymerization form, solution polymerization, emulsion Togane, suspension polymerization, bulk polymerization, etc. can be used, and solution polymerization is particularly preferred. As the radical polymerization catalyst, either an azo initiator or a peroxide initiator can be used. The molecular weight of the copolymer can be arbitrarily changed depending on the use and purpose, but it is preferably about 5,000 to 30,000. In order to obtain a copolymer with a desired molecular weight, if necessary, known and arbitrary additives may be added at the time of polymerization. It is of course possible to use molecular jill adjustment agents and the like. The zero body used in synthesizing the multi-component copolymer can be the same as the medium in which the fleshy polymer substance is dispersed or dissolved.

The fleshy polymeric substance must be dispersed or dissolved in a medium under conditions such that the cationic groups, preferably amino groups, contained in the fleshy polymeric substance are dissociated. The amino group can be dissociated by neutralization with an acidic substance or quaternization. Fiergic substances include hydrochloric acid, nitric acid,
Inorganic acids such as sulfuric acid, sulfurous acid, and phosphoric acid, and organic acids such as vA acid, acetic acid, propionic acid, lactic acid, citric acid, and tartaric acid can be used. Hydrochloric acid, acetic acid, and lactic acid are preferred.

Quaternization can be carried out in a conventional manner using a known quaternizing agent such as an alkyl halide, an aralkyl halide, or epichlorohydrin.

Thus, the dispersant composition of the present invention consisting of a dispersion or solution of an amphoteric polymeric substance dispersed or dissolved in a medium under conditions that dissociate the cationic group can be used as is or optionally with an additional solvent. It can be diluted with water and used in the subsequent polymerization of vinyl monomers, and exhibits a good dispersion effect. In other words, the medium in which the fleshy polymer substance is dispersed or dissolved is used as a polymerization medium in the subsequent polymerization reaction of the vinyl spinning wheel II.

Further, the dispersant composition of the present invention may contain a vinyl compound having a functional group that reacts with an amphoteric polymer substance, such as glycidyl acrylate, glycidyl methacrylate, N-methylolacrylamide, N-methylolmethacrylamide,
(approximately 0.1 to 10% by weight based on a small amount of amphoteric polymer substances such as acrolein and vinyl glycidyl ether)
Modifications can be performed to introduce unsaturated groups into the side chains. Although modification is not absolutely necessary, the dispersion order of the vinyl polymer polymerized using an appropriate amount of modified dispersant composition may give favorable results in terms of its stability and various coating properties. be.

The second invention of the present application is to polymerize a vinyl monomer in the presence of the above-mentioned dispersant composition, and then dissociate the anionic group contained in the amphoteric polymer substance that constitutes the main component of the dispersant. This is a method for producing a dispersion of a vinyl polymer, which is characterized by the following.

The vinyl monomer used here does not need to be the same as the vinyl monomer used when synthesizing the amphoteric polymeric substance. However, the vinyl monomers that are polymerized when producing a vinyl polymer dispersion include those exemplified above as other vinyl monomers that can be copolymerized with monomers containing ionic groups. One or more monomers can be used. Polymerization of vinyl monomers can be carried out according to conventional methods, and the polymerization proceeds rapidly.

After the polymerization is completed, a basic substance is added to dissociate the anionic groups, preferably carboxyl groups. Specific examples of basic substances include alkylamines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, butylamine, monoethanolamine, jetanolamine,
Examples include amino alcohols such as triethanolamine, probanolamine, and dimethylethanolamine, and various organic and inorganic basic substances such as morpholine, ammonia, caustic soda, and caustic potash. Depending on the purpose of the resulting vinyl polymer fraction, if the coating film formed thereon requires water resistance, volatile basic **, m
For example, lower alkylamines and ammonia are preferably used.

The vinyl polymer dispersion obtained according to the present invention described above is a stable microemulsion that is uniform and has a fluorescent color, even when the vinyl polymer has a high glass transition temperature! II property, it is possible to form a heat-resistant, high-gloss coating film. In addition, it has good leakage to each Keyaki pigment, and is useful as a binder for paints and printing inks, various surface finishing agents, etc.

[Function] Based on new findings obtained through research by the present inventors, the present invention utilizes an amphoteric polymer substance as a polymer dispersant, and converts both ionic groups thereof into vinyl monomers. By acting independently on fractional stabilization during and after polymerization, the problems associated with the use of conventional anionic polymer dispersants can be solved at once.

The present inventors are currently investigating the reason why vinyl monomers rapidly polymerize under conditions in which the cationic groups of polymeric dispersants dissociate, resulting in stable polymer dispersions with no residual monomers. Although it is clearly not possible in these cases,
As is clear from the results of Examples and Comparative Examples later, even when the same amphoteric polymer material is used as a dispersant, polymerization of a vinyl-based simple substance occurs in the presence of the dispersant composition of the present invention. It is only when you do this that you will be able to achieve great effects. Therefore, the presence of a cationic group under the above conditions,
It is presumed that the polymerization of vinyl monomers progresses simultaneously.

[Example 1] Next, the present invention will be described in detail with reference to Examples and Comparative Examples, but it goes without saying that the present invention is not limited to these. Note that parts and percentages in the examples are based on weight unless otherwise specified.

Example 1 200 g of isopropanol (IPA) was added to a reactor equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube.
A portion of the flask was charged, and nitrogen gas was passed through the flask to remove oxygen.

Meanwhile, 15 parts of methacrylic acid, 75 parts of methyl methacrylate, 10 parts of dimethylaminoethyl methacrylate, and 2 parts of arabisisobutyronitrile as a radical polymerization catalyst were charged into a dropping funnel, and thoroughly mixed and dissolved to obtain a mixed monomer solution! I! Made by I.

After heating the reactor to 81 parts at 3°C, the above mixed monomer bath liquid was added dropwise over 3 to 3.5 hours.One hour after the completion of the dropwise addition, 0.5 parts of azobisisobutyronitrile was added to the reactor. Incubation was continued for another 1 hour to obtain an isopropanol solution of the amphoteric polymer substance [A]. Weight average molecular weight is io, ooo
Met.

Subsequently, 4 parts of glacial acetic acid and 96 parts of ion-exchanged water were added through the dropping funnel to dissociate the dimethylamino group, which is the cationic group of [A], to form the dispersant composition of the present invention containing an isopropanol-water mixed medium. Product [I] was obtained.

Example 2 100 parts of the dispersant composition [I] obtained in Example 1 was added to
tlN] into a reactor similar to 1. Oxygen was removed by flowing nitrogen gas. Separately, 100 parts by weight of agent composition 1, 11], 50 parts of styrene, and 0.2 parts of azobisiso7-tyronitrile were charged into a dropping funnel, and thoroughly mixed and dissolved to prepare a polymerizable mixture.

After heating 81 parts of the reactor to 3°C, 4 parts of the above Togo mixture was added.
0.1 part of azobisisobutyronitrile was added as a radical polymerization catalyst to the reactor after 71 hours after the 0-drop addition period of 4.5 hours, and the polymerization reaction was completed by keeping the temperature for another 1 hour. Subsequently, the reactor is cooled, and 6 parts of 25% ammonia water is added to the reactor to dissociate the carboxyl group which is an anionic group of the amphoteric polymer substance [A], and the isopropanol-water mixture is used as a dispersion medium. A vinyl polymer dispersion was obtained. This dispersion was an emulsion of ultrafine particles that was uniform and had a fluorescent color, and was a stable dispersion that had no monomer depth at all. The vinyl monomers remaining in this dispersion were quantitatively analyzed by gas chromatography (GC1 method).The results are shown in Table 1.Also, in order to test the coating film properties, the printed paper surface was analyzed using a bar coater N0.8. When the dispersion was coated on the surface, as shown in Table 1, the gloss, water resistance, and heat resistance were all very good.

Comparative Example 1 An isopropanol solution of the amphoteric polymer substance [A] was obtained by the same method as in Example 1, and 25% ammonia water 12
88 parts of ion-exchanged water were added to dissociate the carboxyl group of [A] to obtain a comparative dispersant composition containing an isopropanol-water mixed medium.

100 parts of the above-mentioned dispersant composition (i) was added to the reaction base, and nitrogen gas was passed through the reactor to remove oxygen.

Meanwhile, dispersant composition (i) xo was placed in the dropping funnel.

parts, 50 parts of styrene and 0 parts of azobisisobutyronitrile
．． Two parts were charged, thoroughly mixed and dissolved to prepare a polymerizable mixture.

Thereafter, the polymerization reaction was completed in the same manner as in Example 2 to obtain a vinyl polymer dispersion for comparison. This dispersion was a uniform emulsion of ultrafine particles, but had no fluorescent color and had some monomer depth. This molecule 4tR was tested in the same manner as in Example 2, and the results were
Shown in the table.

Comparative Example 2 Ampholytic polymer ji obtained by the same method as Example 1 [
100 parts of ion-exchanged water was added to the isopropanol solution of A] and mixed uniformly to obtain a comparative dispersant composition (11) containing a propanol-water mixed medium.

Instead of using the dispersant composition [I] in Example 2,
The above dispersant composition? ! After completing the polymerization reaction by performing all the same operations except for using 1(ii), 6 parts of 25% aqueous ammonia was added to dissociate the carboxyl group, and a dispersion of vinyl polymer was prepared for comparison. I got it. This dispersion was either a homogeneous emulsion of ultrafine particles, or had no fluorescent color and had monomer depth.

This dispersion was subjected to the same test as in Example 2, and the results are shown in Table 1.

Comparative Example 3 Ampholytic polymer jl[A
], add isopropatool 100 to the isopropatool solution.
A dispersant composition (11 pieces) was obtained for comparison using isopropanol as a medium.

Instead of using the dispersant composition [I] in Example 2,
Except for using the above dispersant composition (iii), all the same operations were carried out to complete the polymerization reaction, and a dispersion (a) of a vinyl polymer using isopropanol as a dispersion medium was obtained. Table 1 shows the results of quantitative analysis of the vinyl monomer remaining in this dispersion (a).

Subsequently, 25% ammonia water 6 was added to the above dispersion (a).
After adding 95 parts of ion-exchanged water to dissociate the carboxyl groups, about 10 parts of iso-70 panol was removed to form an isopropanol-water mixture with the same composition as the dispersion obtained in Example 2. A vinyl bomber dispersion (b) was obtained for comparison using as a dispersion medium.

This dispersion (b) was an emulsion of ultrafine particles that was uniform and had a fluorescent color, but it had an extremely strong monomer depth. Regarding this dispersion (b), Example 2
A similar test was conducted and the results are shown in Table 1.

Example 3 200 parts of isopropanol was charged into the same reactor as in Example 1, and oxygen was removed by flowing nitrogen gas.

On the other hand, 20 parts of acrylic acid, 72 parts of methyl methacrylate, 8 parts of dimethylamine propylacrylamide, and 2 parts of azobisisobutyronitrile were placed in a dropping funnel, and thoroughly mixed and dissolved to prepare a mixed Zimmer solution.

After heating 81 parts of the reactor to 3°C, the above mixed monomer solution was added dropwise over 3 to 3.5 hours. One hour after the completion of the dropwise addition, 0.5 part of azobisisobutyronitrile was added to the reactor, and the temperature was continued for another hour to form an amphoteric polymer! The weight average molecular weight of the isopropanol solution obtained from [B] is 10,00
It was 0.

Subsequently, 5 parts of 90% lactic acid and 95 parts of ion-exchanged water were added through the dropping funnel to dissociate the dimethylamino group of [B] to form the dispersant composition [11] of the present invention containing an isopropanol-water mixed medium. Obtained.

Example 4 11 parts and 80 parts of the dispersant composition obtained in Example 3 were charged into a similar reactor, and oxygen was removed by flowing nitrogen gas.

On the other hand, a dispersant composition (11 parts, 80 parts, 50 parts of styrene, 10 parts of butyl acrylate, and 0.25 parts of azobisisobutylnitrile) was charged into a dropping funnel, and thoroughly mixed and dissolved to prepare a polymerizable mixture.

Heat the reactor to 81°C and 710°C? Set The above polymerizable mixture was added dropwise over a period of 4 to 4.5 hours. One hour after the completion of the dropwise addition, 0.1 part of azobisisobutyronitrile was added to the reactor.
The temperature was further kept for 1 hour to complete the polymerization reaction. Subsequently, the reactor was cooled, 8 parts of 25% ammonia water was added to the reactor to dissociate the carboxyl group of the amphoteric polymer substance [B], and the vinyl polymer was dispersed using the isopropanol-water mixture as a dispersion medium. I got the liquid. This dispersion was an emulsion of ultrafine particles that was uniform and had a fluorescent color, and was a stable dispersion that had no monomer depth at all. Table 2 shows the results of quantitative analysis of the vinyl monomer remaining on the dispersion surface by GC method.

Comparative Example 4 Isopropanol mR of the amphoteric polymer substance [B] was obtained by the same method as in Example 3, and 25% ammonia water 19
81i of ion-exchanged water was added to dissociate the carboxyl group of [B] to obtain a comparative dispersant composition (iv) containing an iso-10 panol-water mixed medium.

A reactor was charged with 80 parts of the above dispersant composition (iv), and oxygen was removed by flowing nitrogen gas.

Meanwhile, 80 parts of dispersant composition (iv), 50 parts of styrene, 10 parts of butyl acrylate, and 0.25 parts of azopisisobutronitrile were charged into a dropping funnel, and thoroughly mixed and dissolved to prepare a polymerizable mixture. .

Thereafter, the polymerization reaction was completed in the same manner as in Example 4 to obtain a vinyl polymer dispersion for comparison. This dispersion had a monomer depth. Table 2 shows the results of quantitative analysis of residual monomers by GC method.

Example 5 200 parts of ethanol was charged into the same reactor as in Example 1, and oxygen was removed by flowing nitrogen gas.

On the other hand, methacrylic M3o parts, methyl methacrylate 60B, diethylaminoethyl methacrylate 10 parts, and 2 parts of benzoyl peroxide (BPO) as a radical polymerization catalyst were charged into a dropping funnel, and thoroughly mixed and dissolved to prepare a mixed monomer solution.

After heating the reactor to 78±3°C, the above mixed monomer solution was added dropwise over 3 to 3.5 hours.
5 parts of POo were added to the reactor, and the mixture was kept warm for an additional hour to obtain an ethanol solution of the amphoteric polymeric substance [C].

Subsequently, 6 parts of 36% hydrochloric acid and 94 parts of ion-exchanged water were added to dissociate the diethylamino group of [C] to obtain the dispersant compositions [1, 11] of the present invention containing an ethanol-water mixed medium.

Example 6 1111120 parts of the dispersant composition obtained in Example 5 was charged into a similar reactor, and oxygen was removed by flowing nitrogen gas.

Meanwhile, 120 parts of dispersant composition [111], 40 parts of styrene, and 2 parts of BPOo were charged into a dropping funnel, and thoroughly mixed and dissolved to prepare a polymerizable mixture.

After heating the reactor to 78±3°C, the above polymerizable mixture was
BPOo 1 hour after completion of 0 drops dropped in ~4.5 hours
, 1 part was added to the reactor, and the temperature was further kept for 1 hour to complete the polymerization reaction. Subsequently, the reactor was cooled, and 21 parts of triethylamine was added to the reactor to dissociate the carboxyl units, thereby obtaining a dispersion of a vinyl polymer using an ethanol-water mixture as a dispersion medium. This dispersion was an emulsion of ultrafine particles that was uniform and had a fluorescent color, and was a stable dispersion that had no monomer depth at all. Table 3 shows the results of fixed lid analysis of the styrene remaining in this dispersion using the GC method.

Comparative Example 5 An ethanol solution of the amphoteric polymer substance [C] was obtained by the same method as in Example 5, and 35 parts of triethylamine and 65 parts of ion-exchanged water were added thereto to dissociate the carboxyl group of [C1] and form an ethanol-water solution. A comparative dispersant composition containing a mixed medium was given.

120 parts of the above-mentioned dispersant composition (V) is charged into a reactor, and oxygen is removed by flowing nitrogen gas.

On the other hand, 120 parts of the dispersant composition (v), 40 parts of styrene, and 2 parts of BPOo were charged into a dropping funnel, and thoroughly mixed and dissolved to prepare a polymerization mixture.

Thereafter, the polymerization reaction was completed in the same manner as in Example 6 to obtain a vinyl polymer dispersion for comparison. This dispersion was a uniform emulsion of ultrafine particles, but had no fluorescent color and had a slight styrene monomer odor. Table 3 shows the results of cooling the remaining styrene by the GC method.

Example 7 Fruit! [Amphoteric polymer prepared by the same method as 1? A solution of isopropanol of quality [A] was obtained, and 6 parts of epichlorohydrin and 94 parts of ion-exchanged water were added thereto through a dropping funnel. A dispersant composition (IV) containing a mixed medium of Patur and water was obtained.

After completing the polymerization reaction by carrying out all the same operations except for using the above-mentioned dispersant composition (iv) in place of dispersant composition (I) in Example 2, 6 parts of 25% aqueous ammonia was added. was added to dissociate the carboxyl groups to obtain a vinyl polymer dispersion containing R1 g of the isopropanol/water mixture. This dispersion was an emulsion of ultrafine particles that was uniform and had a fluorescent color, and was a stable dispersion that had no monomer depth at all.

[Effects of the Invention] According to the present invention, a dispersant composition for producing a dispersion of a vinyl polymer in which the polymerization rate of a vinyl monomer is extremely high can be obtained.

In addition, the vinyl polymer dispersion obtained by the present invention is a stable microemulsion that is uniform and has a fluorescent color, and even when the vinyl polymer has a high glass transition point, it has poor film-forming properties and has high heat resistance. Can form a glossy coating.

Furthermore, it has good leakage to various pigments and is useful as a binder for paints and printing inks, various surface finishing agents, etc.

Claims (4)

[Claims] (1) A dispersant composition consisting of a dispersion or solution in which an amphoteric polymeric substance containing a cationic group and an anionic group is dispersed or dissolved in a medium under conditions such that the cationic group dissociates. . (2) The dispersant composition according to claim 1, wherein the cationic group is an amino group and the anionic group is a carboxyl group. (3) In a dispersion or solution obtained by dispersing or dissolving an amphoteric polymer substance containing a cationic group and an anionic group in a medium under conditions in which the cationic group dissociates, A method for producing a vinyl polymer dispersion, which comprises polymerizing vinyl monomers and then dissociating anionic groups. (4) Claim 3, wherein the vinyl monomer is at least one of the group consisting of aromatic vinyl monomers, acrylic ester monomers, and methacrylic ester monomers. A method for producing vinyl polymers.