JPH06279539A - Emulsion stabilizer, emulsion produced by using the same, and production of emulsion using the same - Google Patents

Abstract

PURPOSE:To produce an emulsion stabilizer of a cationic polyvinyl alcohol resin by a relatively simple method, provide a cationic polymer emulsion obtd. by the emulsion polymn. using the stabilizer, and provide the method for producing the emulsion. CONSTITUTION:A cationic polymer emulsion is produced by subjecting an ethylenically unsatd. monomer to emulsion polymn. in the presence of an emulsion stabilizer contg. a cationic polyvinyl alcohol resin which has a degree of acetalization of 0.1-40mol% and is expressed by the formula (wherein R1) is H or an alkyl or aralkyl group provided it may contain a hydroxyl group, a carbamoyl group, an ether bond, or an unsatd. bond; R2 is H or 1-5C alkyl; X is an anion selected from the group consisting of halogen, sulfate, methosulfate, methanesulfonate, phosphate, and p-toluenesulfonate; m is 0 or 1; and n is an integer of 1-6).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is used in the polymerization of cationic polymer emulsions used as, for example, paper surface sizing agents, fiber treating agents, soil conditioners, papermaking reinforcing agents and cement admixtures. The present invention relates to an emulsion stabilizer, a polymerized cationic polymer emulsion, and a method for producing a cationic polymer emulsion using the emulsion stabilizer.

[0002]

2. Description of the Related Art In recent years, as a measure for safety of working environment, global environmental problems, reduction of production cost, etc., a social tendency of using organic solvent free is increasing. Demand for polymer emulsions is increasing more and more as a realization of organic solvent removal. Polymer emulsions have a wide range of applications and are used in paints, adhesives, pressure sensitive adhesives, paper surface sizing agents, fiber treatment agents, soil conditioners, papermaking reinforcing agents, cement admixtures and the like.

Conventionally, emulsion stabilizers used during the production of vinyl polymer emulsions are nonionic or anionic surfactants, or water-soluble polyvinyl alcohol resins, hydroxyethyl cellulose, carboxymethyl cellulose, gum arabic, soluble starch, soluble dextrin and the like. It is a usual method to use a volatile polymer alone or in combination. The emulsion particles of an emulsion polymerized in this way are necessarily electrically neutral or negatively charged.

On the other hand, there is a cationic polymer emulsion in which emulsion particles are electrically positively charged. Examples of applications in which the cationic polymer emulsion exhibits superior performance to the anionic or nonionic polymer emulsion include, for example, a paper surface sizing agent, a fiber treating agent, a soil conditioner, a papermaking reinforcing agent, and a cement admixture. To be Despite the wide range of fields of use, cationic polymer emulsions are not widely available on the market. The reason is that it is difficult to produce a stable cationic polymer emulsion having excellent performance.

The cationic polymer emulsion emulsifies a cationic surfactant such as laurylamine salt, stearyltrimethylenediamine salt, octadecylamine salt, laurylpyridinium chloride, stearylammonium chloride, dioleylammonium chloride or octylbenzyltrimethylammonium chloride. It can be produced by using it as a stabilizer. In addition, a method is also known in which after emulsion polymerization using a nonionic surfactant, a cationic substance such as the above-mentioned cationic surfactant, polyoxyethylene alkylamine, or polyethyleneimine is added afterwards. ing. However, most of the cationic surfactants have many problems in terms of toxicity and are currently limited in their use range. The cationic polymerization initiator, for example 2,2 ^'- azobis (2-aminopropane) hydrochloride and 2,2' method of cationized emulsion particle emulsion polymerization to using such azobisisobutylamidine hydrochloride However, it is not possible to impart sufficient cationicity to the emulsion particles by this method. Furthermore, a method in which dimethylaminoethyl methacrylate hydrochloride and other monomers are copolymerized in the absence of an emulsifier, and then this copolymer is used as a protective colloid to carry out emulsion polymerization of the desired monomers. Is also advocated. This method has complicated control of the manufacturing process, and it is difficult to manufacture a stable product.

On the other hand, polyvinyl alcohol resins are known as excellent emulsion stabilizers. It is used for the production of emulsion emulsions of vinyl acetate and ethylene, acrylic acid esters, maleic acid diesters, vinyl versatate copolymers, etc., including single emulsion polymerization of vinyl acetate without using a surfactant. An emulsion with excellent stability is obtained. The polyvinyl alcohol-based resin used as the emulsion stabilizer is a partially saponified product, in particular, one in which residual acetic acid groups are appropriately dispersed in a block form.
Thus, the emulsion polymerized by using the polyvinyl alcohol-based resin as an emulsion stabilizer has the advantage that the protective layer of the emulsion particles is thicker than the emulsion particles emulsion-polymerized by using a surfactant, and thus has good stability. . On the other hand, the emulsion obtained is only electrically neutral and has a large particle size of 1 μm or more.

As a method of using a polyvinyl alcohol resin as an emulsion stabilizer to obtain an emulsion having a small particle size and good stability, JP-A 1-240501 discloses a modified polyvinyl alcohol having a linear alkyl group introduced at the end. A method for emulsion-polymerizing vinyl chloride using is disclosed. The polymer emulsion obtained in this way is anionic. As a method of introducing a cationic group into polyvinyl alcohol to obtain a cationic polymer emulsion, a method of aminoacetalization, a method of reducing cyanoethylated polyvinyl alcohol, a method of etherifying polyvinyl alcohol with epichlorohydrin and reacting with amine can be used. Modification methods by molecular reaction are known. In these methods, the conditions of introduction are strongly acidic or strongly alkaline, so it is extremely difficult to obtain a modified polyvinyl alcohol resin in the state of a partially saponified polyvinyl alcohol resin suitable as an emulsion stabilizer. In order to solve this problem, JP-A-60-4503, JP-B-63-441, and JP-B-1-44723 disclose that a monomer having a cationic group is copolymerized with vinyl acetate. , A method of obtaining a cationic polyvinyl alcohol by saponification is disclosed. Such a method using copolymerization requires special equipment for polymerization, and it is difficult to control the manufacturing process. The particle size of the obtained emulsion is 1
Greater than μ and relatively large. The smaller the emulsion particle size, the larger the surface area of the emulsion polymer in the same weight and the more efficient use thereof, but the emulsion polymer having such a large particle size has poor utilization efficiency.

[0008]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and uses an emulsion stabilizer necessary for emulsion-polymerizing an ethylenically unsaturated monomer and the emulsion stabilizer. It is an object to provide a method for producing a cationic polymer emulsion and an emulsion using an emulsion stabilizer.

[0009]

The emulsion stabilizer of the present invention, which has been made to achieve the above object, has the following formula:

[0010]

[Chemical 2]

[Wherein R ₁ represents a hydrogen atom, an alkyl group or an aralkyl group, and may contain a hydroxyl group, a carbamoyl group, an ether bond or an unsaturated bond, and R 1
₂ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms,
X is a halogen ion atom, a sulfate group, a methosulfate sulfate group (methosulfate group), a methanesulfonic acid group, a phosphoric acid group,
Or an anion selected from p-toluenesulfonic acid group, m is 0 or 1, n is an integer of 1 to 6], and the degree of acetalization is 0.1 to 40 mol%. It contains alcohol resin,
It is an acetalized product of a polyvinyl alcohol resin and a cationic aldehyde.

The cationic polyvinyl alcohol resin, which is the main constituent of the emulsion stabilizer, has a desired polymerization degree, saponification degree and cation by a method of introducing a cationic group into a known polyvinyl alcohol resin by an acetalization reaction. Obtained by the degree of denaturation. In manufacturing, it can be obtained with a relatively simple device and manufacturing process control.

The polyvinyl alcohol resin which is a raw material for obtaining the cationic polyvinyl alcohol resin is
Polyvinyl alcohol having a saponification degree of 70 mol% or more, a polymerization degree of 300 or more, preferably a saponification degree of 75 mol% to 95 mol% and a polymerization degree of 500 to 3000. A copolymer resin obtained by saponifying an acetyl group of a copolymer of vinyl acetate and, for example, maleic acid, fumaric acid, acrylic acid, methacrylic acid, sulfostyrene, or acid phosphooxyethylene methacrylate, or a copolymer of succinic anhydride Polyvinyl alcohol-based resins also include acid anhydride modified products obtained by reacting acid, maleic anhydride, phthalic anhydride and the like. Examples of the cationic aldehyde include 1-methyl-2- (p-formylstyryl) pyridinium and 1-methyl-4- (p-
Formylstyryl) pyridinium, 1-ethyl-2-
(P-Formylstyryl) pyridinium, 1-ethyl-
4- (p-formylstyryl) pyridinium, 1-aryl-4- (p-formylstyryl) pyridinium, 1
-(2-hydroxyethyl) -4- (p-formylstyryl) pyridinium, 1-methyl-2- (m-formylstyryl) pyridinium, 1-benzyl-2- (p-formylstyryl) pyridinium, 1-methyl- 4- (p
-Formylstyryl) -5-ethylpyridinium and other pyridinium halogen chlorides, sulfates, methosulfates,
Examples thereof include salts such as p-toluenesulfonate and methanesulfonate.

The method of acetalization by introducing these cationic aldehydes into a polyvinyl alcohol resin is as follows:
Polyvinyl alcohol-based resin was dissolved to form an aqueous solution having a concentration of 5 to 20% by weight, kept warm at 70 to 90 ° C., a predetermined amount of the above cationic aldehyde was added, and after stirring and mixing, phosphoric acid, hydrochloric acid, sulfuric acid, etc. The pH of the aqueous solution is adjusted to 3 or less, preferably 2.5 or less with an inorganic acid, reacted for several hours, and then neutralized with sodium hydroxide, ammonium hydroxide or the like. The introduction rate of the cationic aldehyde into the polyvinyl alcohol resin, that is, the degree of acetalization is 0.1 to 40 mol%, preferably 0.5 to 30 mol%. The obtained cationic resin aqueous solution can be used as it is as an emulsion stabilizer for emulsion polymerization.

Examples of the ethylenically unsaturated monomer usable in the emulsion polymerization of the present invention include vinyl acetate, vinyl propionate, vinyl versatate, vinyl chloride and other vinyl esters, methyl (meth) acrylate, and (meth) acrylate.
(Meth) acrylic acid esters such as ethyl acrylate, butyl (meth) acrylate, octyl (meth) acrylate, unsaturated carboxylic acid amides such as (meth) acrylamide and methylolacrylamide, (meth) acrylic acid, maleic acid Unsaturated carboxylic acids such as fumaric acid and itaconic acid, ethylene, styrene and the like can be mentioned, and all of them are carried out by homopolymerization or copolymerization. As the polymerization initiator, commonly used hydrogen peroxide, potassium persulfate, ammonium persulfate, cumene hydroperoxide, etc. can be used alone or in combination, and these polymerization initiators can be used in an amount of 0 to the ethylenically unsaturated monomer. It is preferably used in the range of 0.01 to 5 parts by weight. The temperature at which the emulsion is polymerized is 30 to 100 ° C., preferably 40.
To 90 ° C., and the pH during polymerization is 4 to 7.

[0016]

[Function] When a cationic polyvinyl alcohol resin is used as an emulsion stabilizer, a cationic polymer emulsion obtained by emulsion-polymerizing an ethylenically unsaturated monomer having a small particle size, high stability and high cationic performance is obtained. To be

[0017]

The cationic polyvinyl alcohol resin of the present invention is an emulsion having a desired degree of polymerization, saponification degree and cationic modification by a method of introducing a cationic group into a general-purpose polyvinyl alcohol resin by an acetalization reaction. Stabilizers can be obtained with relatively simple equipment and manufacturing process control. The emulsion stabilizer is effective in polymerizing a cationic polymer emulsion obtained by emulsion-polymerizing an ethylenically unsaturated monomer having a particle size of 0.5 μm or less and being stable and having high cationic performance. The cationic polymer emulsion polymerized by the production method of the present invention has a strong adhesive force and adsorptive force which are not present in conventional emulsions, against substances that tend to be negatively charged, such as pulp, fibers, glass, and porcelain clay. Show.

[0018]

EXAMPLES Examples of the present invention will be described in detail below. The following Synthesis Examples 1 to 3 show the synthesis of the cationic polyvinyl alcohol resin according to the present invention. Examples 1 to 4 evaluate the polymerization of the cationic polymer emulsion and the performance of the emulsion when the cationic polyvinyl alcohol resins synthesized in Synthesis Examples 1 to 3 are used as an emulsion stabilizer. Comparative Examples 1 to 3
Is for synthesizing a polymer emulsion using an emulsion stabilizer to which the present invention is not applied and evaluating the performance of the emulsion.

Synthesis Example 1 Partially saponified polyvinyl alcohol resin having a saponification degree of 89 mol% and a polymerization degree of 2400 ("PA-24" manufactured by Shin-Etsu Chemical Co., Ltd.)
While stirring and mixing 10 g and 90 g of water, the temperature was raised to 90 ° C. to completely dissolve the polyvinyl alcohol resin. Next 1
-Methyl-4- (p-formylstyryl) pyridinium methosulfate compound (3.4 g) was added and stirred, followed by cooling to 75 ° C, adding phosphoric acid (0.3 g) and reacting for 5 hours.
The pH was adjusted to 6 with a 0.1N sodium hydroxide aqueous solution. By this reaction, a cationic polyvinyl alcohol resin having an acetalization degree of 4.8 mol% was obtained.

Synthesis Example 2 Partially saponified polyvinyl alcohol resin having a saponification degree of 89 mol% and a polymerization degree of 1800 ("PA-18" manufactured by Shin-Etsu Chemical Co., Ltd.)
While stirring and mixing 10 g and 90 g of water, the temperature was raised to 90 ° C. to completely dissolve the polyvinyl alcohol resin. Next 1
-Methyl-4- (p-formylstyryl) pyridinium methosulfate compound (6.8 g) was added and stirred, and the mixture was cooled to 75 ° C, 0.3 g of phosphoric acid was added, and the mixture was reacted for 5 hours.
The pH was adjusted to 5 with an aqueous sodium hydroxide solution. By this reaction, a cationic polyvinyl alcohol-based resin having an acetalization degree of 9.5 mol% was obtained.

Synthesis Example 3 Partially saponified polyvinyl alcohol resin having a saponification degree of 85 mol% and a polymerization degree of 600 (“LA-05” manufactured by Shin-Etsu Chemical Co., Ltd.) 2
While stirring and mixing 0 g and 80 g of water, the temperature was raised to 95 ° C. to completely dissolve the polyvinyl alcohol resin. Next 1-
Ethyl-2- (p-formylstyryl) pyridinium methosulfate compound 18 g was added and stirred, then cooled to 75 ° C., 0.3 g of phosphoric acid was added and reacted for 5 hours, and the pH was adjusted with 0.1N sodium hydroxide aqueous solution. Adjusted to 5. By this reaction, a cationic polyvinyl alcohol resin having an acetalization degree of 14.3 mol% was obtained.

Example 1 180 g of the cationic polyvinyl alcohol resin of Synthesis Example 1 and 120 g of distilled water were placed in a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser, and the mixture was stirred and heated to obtain vinyl acetate monomer. 180g was added and it heated up at 60 degreeC.
Next, 6 g of 60% hydrogen peroxide solution was added, and emulsion polymerization was carried out at this temperature for 3 hours. The obtained cationic polyvinyl acetate emulsion had a resin concentration of 50%. This emulsion was measured for the following 5 items (1) to (5). (1) Particle diameter: The resin particle diameter was measured with an electron microscope. (2) Dilution stability: Synthesized emulsion was diluted with distilled water to a concentration of 3%, and then 30m
1 was placed in a 20 cm long flat-bottomed test tube, tightly capped, and allowed to stand for 3 days, and then the volume of the supernatant (A) and the volume of the portion settled on the bottom (B) were measured, and the volume ratio of the supernatant was measured. (U = A / 30 × 1
00) and the volume ratio of the sedimented portion (P = B / 30 × 10
The dilution stability was calculated from 0). (3) Pulp adsorption rate:
2 in 1000 g of 5% slurry of 100 mesh pass pulp ("Pulp Flock W-1" manufactured by Sanyo Kokusaku Pulp Co., Ltd.)
10% by adding 100 g of the synthesized emulsion having a concentration of 10%
After stirring for a minute, the pulp was filtered off, the amount of emulsion in the filtrate was measured, and the amount of adsorption on the charged pulp was calculated. (4)
Adsorption rate of white clay: White clay (reagent manufactured by Katayama Chemical Co., Ltd.) 5% slurry 10%, synthesized 2% in 1000 g slurry 10
After adding 0 g and stirring for 10 minutes, the pulp was separated by filtration, the amount of emulsion in the filtrate was measured, and the amount of adsorption to the negatively charged white clay was calculated. (5) Adhesive strength with glass: Apply the synthesized emulsion on a glass plate with a bar coater, and apply 70
It was dried at 0 ° C. for 10 minutes to form a film having a thickness of 50 μm.
This coating was cut with a knife vertically and horizontally so as to be 1 mm square, and then a cellotape peeling test was performed to observe the peeled state of the coating at that time. The evaluation results of this emulsion are shown in Table 1.

Example 2 In a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser, 120 g of the cationic polyvinyl alcohol resin of Synthesis Example 1 and 200 g of distilled water were put and stirred to obtain 80 g of vinyl acetate monomer. 10 g of ethyl acrylate was uniformly emulsified, 4 g of 10% ammonium persulfate and 1 g of 10% sodium bisulfite were added, and the temperature was raised to 60 ° C. to initiate polymerization. While maintaining at 60 ° C., a mixture of 80 g of vinyl acetate monomer, 10 g of ethyl acrylate and 8 g of 3% ammonium persulfate was added and polymerized for 2 hours and 30 minutes. After the dropping was completed, polymerization was further performed at this temperature for 1 hour. The obtained cationic vinyl acetate-ethyl acrylate copolymer emulsion had a resin concentration of 50%. For this emulsion, items (1) to (1) similar to those in Example 1
The measurement was performed for (5), and the evaluation results of this emulsion are shown in Table 1.

Example 3 In a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser, 250 g of the cationic polyvinyl alcohol resin of Synthesis Example 2 and 100 g of distilled water were put and stirred, and 60 g of vinyl acetate and acryl were used. 10 g of ethyl acidate and 5 g of trimethyl roll propane triacrylate were uniformly emulsified and 6 g of 10% cumene hydroperoxide was added.
The temperature was raised to ℃ and the polymerization was started. While maintaining at 70 ℃,
60 g of vinyl acetate monomer, 10 g of ethyl acrylate,
Trimethylolpropane triacrylate 3 g and 1
A mixture of 3 g of 0% cumene hydroperoxide was added and polymerized for 3 hours. After the dropping was completed, polymerization was further performed at this temperature for 1 hour. The cationic vinyl acetate-ethyl acrylate-trimethylolpropane triacrylate copolymer emulsion obtained had a resin concentration of 40%. The same items (1) to (5) as in Example 1 were measured for this emulsion, and the evaluation results of this emulsion are shown in Table 1.

Example 4 In a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser, 100 g of the cationic polyvinyl alcohol-based resin of Synthesis Example 3 and 120 g of distilled water were put and stirred to uniformly prepare 140 g of vinyl acetate. The emulsion was emulsified in 10%, 40 g of cumene hydroperoxide was added, and the temperature was raised to 70 ° C. to initiate polymerization. While maintaining at 70 ℃, vinyl acetate monomer 1
A mixture of 40 g and 15 g of 10% cumene hydroperoxide was added and polymerized for 3 hours. After the dropping was completed, polymerization was further performed at this temperature for 1 hour. The obtained cationic polyvinyl acetate emulsion had a resin concentration of 55%. The same items (1) to (5) as in Example 1 were measured for this emulsion, and the evaluation results of this emulsion are shown in Table 1.

COMPARATIVE EXAMPLE 1 Instead of the cationic PAV-based resin used in Example 1, a non-cationic saponification degree of 89 mol% and a polymerization degree of 240 were used.
This reaction system was adjusted to pH 4 with a 40% acetic acid aqueous solution while dissolving 10 g of partially saponified polyvinyl alcohol of 0 (“PA-24” manufactured by Shin-Etsu Chemical Co., Ltd.) and 80 g of distilled water. Using this reaction system, a polyvinyl acetate emulsion was prepared in the same manner as in Example 1. The resulting emulsion is nonionic and the evaluation is shown in Table 1. For this emulsion, items (1) to (1) similar to those in Example 1
The measurement was performed for (5), and the evaluation results of this emulsion are shown in Table 1.

Comparative Example 2 Emulsion obtained by emulsion polymerization of vinyl acetate in the presence of a copolymer of 2-hydroxy-3-methacryloxypropyltrimethylammonium chloride and vinyl acetate. The evaluation is shown in Table 1. The same items (1) to (5) as in Example 1 were measured for this emulsion, and the evaluation results of this emulsion are shown in Table 1.

Comparative Example 3 Instead of the cationic polyvinyl alcohol resin in Example 2, partially saponified polyvinyl alcohol (“PA-18” manufactured by Shin-Etsu Chemical Co., Ltd.) having a saponification degree of 89 mol% and a polymerization degree of 1800, which was not made cationic, was used. A vinyl acetate-ethyl acrylate copolymer emulsion was prepared in the same manner as in Example 2 except that the cationic emulsifier cetyltrimethylammonium chloride was also used. The resulting emulsion was cationic and the evaluations are shown in Table 1. For this emulsion, items (1) to (1) similar to those in Example 1
The measurement was performed for (5), and the evaluation results of this emulsion are shown in Table 1.

[0029]

[Table 1]

* 1 ○: The added value of U and P was less than 5%.

Δ: The added value of U and P was less than 5 to 15%.

X: The added value of U and P was 15% or more.

* 2 ◯: No peeling occurred at all.

Δ: The peeled portion was less than 10%.

X: The peeled portion was 10% or more.

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[Procedure amendment]

[Submission date] June 28, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

Examples of the ethylenically unsaturated monomer usable in the emulsion polymerization of the present invention include vinyl acetate, vinyl propionate, vinyl versatate, vinyl chloride and other vinyl esters, methyl (meth) acrylate, and (meth) acrylate.
(Meth) acrylic acid esters such as ethyl acrylate, butyl (meth) acrylate, octyl (meth) acrylate, unsaturated carboxylic acid amides such as (meth) acrylamide and methylolacrylamide, (meth) acrylic acid, maleic acid Unsaturated carboxylic acids such as fumaric acid and itaconic acid, ethylene, styrene and the like can be mentioned, and all of them are carried out by homopolymerization or copolymerization. Also,
As the polymerization initiator, hydrogen peroxide, potassium persulfate, ammonium persulfate, cumene hydroperoxide and the like which are commonly used can be used alone or in combination. These polymerization initiators can be used in an amount of 0.01 to 0.01 with respect to the ethylenically unsaturated monomer. It is preferably used in the range of 5 parts by weight. The temperature at which the emulsion is polymerized is 30 to 100 ° C., preferably 40 to 90 ° C., and the pH at the time of polymerization is 4 to 7.

Claims (3)

[Claims] 1. The following formula: [In the formula, R ₁ represents a hydrogen atom, an alkyl group or an aralkyl group, and may contain a hydroxyl group, a carbamoyl group, an ether bond or an unsaturated bond, and R ₂ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Is a group, X is an anion selected from a halogen ion atom, a sulfate group, a methosulfate sulfate group (meth sulfate group), a methanesulfonic acid group, a phosphoric acid group, or a p-toluenesulfonic acid group, and m is 0 or 1 , N is an integer of 1 to 6], and an emulsion stabilizer containing a cationic polyvinyl alcohol resin having an acetalization degree of 0.1 to 40 mol%. 2. A cationic polymer emulsion of a vinyl polymer containing the cationic polyvinyl alcohol resin according to claim 1 as an emulsion stabilizer. 3. A method for producing a cationic polymer emulsion, which comprises emulsion-polymerizing an ethylenically unsaturated monomer in the presence of the cationic polyvinyl alcohol resin according to claim 1.