JPH01146907A - Polymer emulsion and its preparation - Google Patents

Abstract

PURPOSE:To prepare a polymer emulsion whose particle surface is provided with a cationic property in a high density, by a method wherein a product obtd. by polymerizing a specified seed latex with a specified monomer is neutralized with an acid or a salt or converted into a quat. ammonium salt with a quaternizing agent. CONSTITUTION:A seed latex consisting of a carboxyl-modified synthetic rubber latex or synthetic resin emulsion, neutralized to a pH of at least 6, is polymerized with a monomer of formula I (where R1 is H or CH3; R2 is a 2-5C alkylene; R3 and R4 are H or a 1-5C alkyl; A is a group of formula II or III; R1, R3 and R4 are each selected in such a range that the monomer is hardly soluble or insoluble in water), or its mixture with an ethylenically unsatd. monomer copolymerizable therewith in such an amt. that the monomer of formula I is at least the colloid equivalent (absolute value) of the seed latex, in the presence of a radical polymn. initiator. The seed polymer obtd. thereby is neutralized with an acid or a salt or converted into a quat. ammonium salt with the addition of a quaternizing agent to give a polymer emulsion whose particle surface is provided with a cationic property in a high density.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a stable polymer emulsion in which cationic groups can be densely distributed at least on the surface of latex particles, and a method for producing the same, and particularly to a method for producing the same by imparting cationic properties. , pulp and synthetic fibers.

Paper strength increasing binder or fixing agent, retention improver, etc. in beater size processing during inorganic fiber papermaking, flocking,
Suitable for use as a binder for nonwoven fabrics, carpet backings, etc., texture processing of fibers, antistatic processing, waterproofing agents, etc., as well as mortar, cement admixtures, asphalt admixtures, other adhesives, and raw materials for paints. This invention relates to a polymer emulsion and a method for producing the same.

BACKGROUND OF THE INVENTION Carboxyl-modified latexes have been used in the past as binders for various types of fibers, asphalt, mortar, concrete, ceramics, and the like.

In addition, various cationic polymer emulsions have been proposed, but few of them are sufficiently effective for their intended use, and their production methods are also complicated.

For example, there is a method of copolymerizing a cationic monomer with another monomer by seed polymerization without using an emulsifier or using a cationic surfactant. This is a method in which a seed latex is made using the entire amount of cationic monomer and a portion of other monomers, and the remaining monomers are added to this.
A large number of cationic groups cannot be present on the particle surface, and stable polymerization cannot be performed (JP-A-57-121048, JP-A-59-142217).

In addition, ethylenically unsaturated monomers containing a cationic group-giving agent consisting of a secondary, tertiary amine, or quaternary ammonium salt, and ethylenically unsaturated monomers copolymerizable with these There is a method in which a part of the monomer is polymerized in the presence of a chain transfer agent in an aqueous medium to form a seed latex, and then the remaining monomer is added to continue the polymerization (No. 081-281302).
.

Unlike the former method, this method uses a monomer added to the seed latex that contains a cationic group imparting agent, so it can be expected to have the effect of imparting a cationic group to the particle surface to some extent; The manufacturing process is complicated, as the seed latex is manufactured in the presence of a chain transfer agent.

Problems to be Solved by the Invention The present invention is based on a known carboxyl-modified latex,
By using monomers that are poorly soluble or insoluble in water, there is less cation dissociation during polymerization, and the production method is simple and more stable seed polymerization is possible, and the polymer is neutralized with acid or salt, or quaternary polymerization is possible. The object of the present invention is to provide a polymer latex which can impart cationic properties to the surface of latex particles at high density by converting it into a quaternary ammonium salt with a curing agent.

Means for Solving the Problems The present inventors used a known synthetic rubber latex or synthetic resin emulsion as a seed latex, and seed latex with a specific monomer. By neutralizing with a salt or converting to a quaternary ammonium salt with a quaternizing agent, it is possible to have cationic groups present in a high density on the surface of the polymer particles, and the particles of the emulsion are stable. The present invention was achieved based on the discovery that the manufacturing method is simple, does not require complicated operations, and is economically advantageous.

That is, in the present invention, a synthetic rubber latex or a synthetic resin emulsion is used as a seed latex.

A seed polymer emulsion obtained by adding and polymerizing a monomer represented by the following general formula [I] or a mixture with an ethylenically unsaturated monomer copolymerizable with these, and
A polymer emulsion characterized by imparting cationic properties to the latex surface at high density by neutralizing it with an acid or salt or converting it into a quaternary ammonium salt with a general quaternizing agent, and a method for producing the same. It is.

\ Kame (t, dashi, R3 in the formula is H or CH3, R is a fullkylene group having 2 to 5 carbon atoms, Kame and Kame are H or carbon-C
-NH-, and R1, R3 and tome are selected within the range in which the monomer is poorly soluble or insoluble in water. ) Effect The present invention will be further explained in detail below.

Any known synthetic rubber latex or synthetic resin emulsion can be used in the present invention. However, nonionic ones have poor stability, and cationic ones are rare, and anionic ones are usually preferably used.

Specific examples of these include synthetic rubber latex,
Styrene-butadiene rubber (SBR), methyl methacrylate-butadiene rubber (MBR), acrylonitrile-butadiene rubber (NBR), or rubbers containing these and other monomer components (α), chloroprene rubber (C
R), carboxyl-modified latex such as isoprene rubber (IR), and synthetic resin emulsions include acrylic ester-based, vinyl acetate-based, vinyl chloride-based, styrene-based polymers or copolymers, and ethylene/vinyl acetate. Examples include emulsions obtained by carboxyl-modifying copolymers, ethylene/vinyl chloride copolymers, and the like.

Next, the specific monomer used in the present invention has the general formula [
I] and ethylenically unsaturated monomer (II) which is copolymerizable with these monomers.

Specific examples of the monomer represented by general formula (1) include diethylamine ethyl acrylate, diethylaminoethyl methacrylate, dipropylaminoethyl acrylate, dipropylaminoethyl methacrylate, dibutylaminoethyl methacrylate, t-butyl Aminoethyl (meth)acrylate, diethylaminopropyl methacrylamide, dipropylaminopropyl methacrylamide, dipropylaminopropyl acrylamide, dibutylaminopropyl methacrylamide,
Examples include dibutylaminopropylacrylamide.

Examples of other ethylenically unsaturated monomers (II) copolymerizable with monomer [I] include hydrophobic monomers such as acrylic esters, methacrylic esters, acrylonitrile, styrene, and vinyl acetate; , N'-methylenebisacrylamide, diallyl phthalate, divinylbenzene, and (poly)ethylene glycol di(meth)acrylate.

The usage amounts of the above raw materials are as follows.

The proportion of the monomer represented by general formula [I] to the seed latex is 5 to 50% by weight, preferably 10 to 30% by weight.
That's about it.

Since the colloidal equivalent value of general carboxyl-modified latex is -0.2 to -0.1 eq/g, the general formula [
When the proportion of the monomer shown in [I] is 5% by weight without swirling, there are too few cationic groups and a stable cationic latex cannot be obtained.When it exceeds 50% by weight, the cationic groups are excessive, and It is also economically disadvantageous.

Note that the colloid equivalent value is a value obtained by the following method.

Take 95 wa of distilled water in a beaker and add a sample of 11,000 pp.
Add the solution to 5. Add Q, adjust pH to 4.0 with 1% HCII,
Stir for about 1 minute. Then add 2-3 drops of toluidine blue indicator solution and titrate with N/400 PVSK. The titration rate is 2 minutes per minute, and the end point is when the sample water changes color from blue to red and remains for 10 seconds or more.

Colloidal equivalent value (meq/g) (However, F is a factor.) Monomer (II) may be determined depending on the glass transition point and physical properties of the target latex, but usually monomer [I] About 0-40% by weight is used.

The polymerization method involves diluting the seed latex with water or adjusting the pH of the system to 6 or higher without diluting it, then adding the monomer and stirring at a temperature of 20 to 80°C in the presence of a radical polymerization initiator. Seed polymerization.

If the pH of the system is less than 6, gelation occurs during monomer addition or polymerization, making it impossible to obtain a stable emulsion.Also, the polymerization temperature is not particularly limited under normal pressure, but in practical terms
-80°C, preferably 30-60°C.

In this case, it is not necessary to specifically add a surfactant, but if the content is insufficient, it can be added according to a conventional method.

In addition, the radical polymerization initiator used in the present invention includes:
Those used in ordinary emulsion polymerization can be used.

For example, ammonium persulfate, potassium persulfate, inorganic peroxides such as hydrogen peroxide, azobisisobutyronitrile,
2. Aliphatic azo compounds such as 2'-azobis(2,4-dimethylvaleronitrile, 2.2'-azobis(2-amidinopropane) hydrochloride, azobis(N,N'-dimethyleneisobutyramidine) salt) hydroperoxides such as benzoyl peroxide, t-butyl hydroperoxide, diisopropylbenzene hydroperoxide, cumene hydroperoxide, the above peroxides and 7-scorbic acid, polyvalent metal salts, acidic sodium sulfite, Examples include redox systems in combination with reducing agents such as sodium formaldehyde sulfosylate.

The amount μ of these polymerization initiators used may be about 1.0 to 5.0% by weight based on the monomer, and the polymerization method may be either batchwise or continuous.

Then, by neutralizing the obtained polymer with an acid or salt, or converting it into a quaternary ammonium salt using a general quaternizing agent, a cationic polymer emulsion in which cationic groups are densely distributed on the latex particle surface is produced. can get.

The cationization method involves combining the obtained seeds, stirring at room temperature, adding an acid, salt, or quaternizing agent to the monomer [
I] in an equivalent amount. Neutralization is completed instantly, and quaternization is usually completed in about 5 to 30 minutes.

Examples of acids include inorganic acids such as hydrochloric acid and sulfuric acid, organic acids such as acetic acid, adipic acid, citric acid, and formic acid, and acid salts such as sodium hydrogen sulfate and sodium dihydrogen phosphate.
Grading agents include methyl chloride, ethyl chloride, methyl bromide,
Alkyl halides such as methyl iodide, dimethyl sulfate,
Common alkylating agents such as diethyl sulfate can be used.

Further, in the present invention, the polymer obtained by seed polymerization can be processed into, for example, a film and then cationized in the same manner as described above.

When the polymer emulsion of the present invention is cationized, it has cationic properties, antistatic properties, wood-philic properties, and polar affinity. Various m-fiber binders, mix
It is used for texture processing, antistatic processing, waterproofing, paint, adhesive raw material, concrete mixing, asphalt mixing, etc.

This will be explained below with reference to examples.

Example 1 701.3 g of carboxyl-modified SBR latex (pH 8.3, solid content 48%, anionic colloid equivalent value 0.18 meq/g), N, N' in a flask with a stirrer.
- 0.4 g of methylenebisacrylamide, and 15 g of water
Add 9.7 g of diethylaminoethyl methacrylate) and add 37.5 g of dimethyl sulfate while stirring well.
Cation colloid equivalent value as graded product: Q, 51 e
q/g) was added dropwise using a dropping funnel, and then left to stand for 1 hour while blowing in gas. After standing, 80 g of a 1% potassium persulfate aqueous solution was added, and the mixture was heated to 50° C. for polymerization. Polymerization was completed after about 2 hours.

Example 2 A stable polymer emulsion was obtained in the same manner as in Example 1, except that N,N'-methylenebisacrylamide was not added.

Example 3 530 g of carboxyl-modified MBR latex (pH 8.8, solid content 45%, anion colloid equivalent value: -0.20 meq/g) and 55 g of water were placed in a flask equipped with a stirrer, and while stirring well, 20 g of methyl methacrylate was added. , and diethylaminoethyl methacrylate
) After dropping 40 g using a dropping funnel, it was left for 1 hour while blowing horse gas. After standing, 120 g of 1% potassium persulfate was added, and the mixture was heated to 40°C to polymerize. Polymerization was completed after about 3 hours.

Example 4 A stable polymer emulsion was obtained in the same manner as in Example 3 except that vinyl acetate was used instead of methyl methacrylate.

Example 5 A stable polymer emulsion was obtained in the same manner as in Example 1 except that diethylaminoethyl methacrylate was changed to t-butylaminoethyl methacrylate.

Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 except that the pH of the polymerization system was adjusted to 5.8.
It gelled after minutes.

Comparative Example 2 In Example 1, 37.5 g of diethylamine ethyl methacrylate was added to 13.2 g (cation colloid equivalent value as dimethyl sulfate quaternized product: O, 18 meq/g)
) A stable polymer emulsion was obtained by the same procedure except that

Comparative Example 3 Polymerization was carried out in the same manner as in Example 1 except that diethylaminoethyl methacrylate was changed to dimethylaminoethyl methacrylate (water-soluble monomer), and gelation occurred immediately after the start of polymerization.

The above Examples and Comparative Examples are listed in Table-1.

(Left below) Next, while stirring the polymer emulsion in Table 1, an equivalent amount of dimethyl sulfate was added to monomer [I] at room temperature, and the mixture was left to stand for 30 minutes to perform quaternization. .

The degree of cationization is indicated by toluidine blue! =
Lte, pHa, oNio /400P, V, S
The colloidal equivalent value was measured by . The results are shown in Table-2.

Table 2: Effects of the Invention of Kakou Δ Raw Polymer Emulsion The present invention uses a ready-made polymer latex as the seed latex, which saves the effort of preparing the first kind of latex, and allows for stable seed polymerization, resulting in the resulting emulsion. The particle size is uniform and the storage stability is good.

Products with various properties can be prepared by selecting the seed latex and the type of monomer. Furthermore, since the material is cationized by post-denaturation, the cationization density on the surface is high. It has useful uses such as various admixtures and paper processing agents.

Claims (5)

[Claims] (1) A carboxyl-modified synthetic rubber latex or synthetic resin emulsion is used as a seed latex, and a monomer represented by the following general formula [I] or an ethylenically unsaturated monomer copolymerizable with these is added to the seed latex. The seed polymer obtained by addition polymerization of the mixture with [II]] is neutralized with an acid or salt, or it is converted into a quaternary ammonium salt using a quaternizing agent to impart cationic properties to the surface of the emulsion particles at a high density. A polymer emulsion characterized in that it has been added. General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼〔I〕 (However, R_1 in the formula is H or CH_3, R_2
is an alkylene group with 2 to 5 carbon atoms, R_3 and R_4 are H or an alkyl group with 1 to 5 carbon atoms, and A is ▲There are mathematical formulas, chemical formulas, tables, etc.▼or▲There are mathematical formulas, chemical formulas, tables, etc.▼ , R_1
, R_3, and R_4 are selected within a range in which the monomer is poorly soluble or insoluble in water. ) (2) The polymer emulsion according to claim (1), wherein the amount of the monomer of general formula [I] added is at least the colloidal equivalent value (absolute value) of the carboxyl-modified latex. (3) A carboxyl-modified synthetic rubber latex or a synthetic resin emulsion is used as a seed latex, and after neutralizing this seed latex to a pH of 6 or more, the general formula [
A monomer represented by the following general formula [ I
] To the seed polymer obtained by adding the monomer shown in at least a proportion equal to or higher than the colloidal equivalent value (absolute value) of the seed latex, and then polymerizing it using a radical polymerization initiator,
A method for producing a polymer emulsion, characterized in that it is neutralized by adding an acid or salt, or is converted to a quaternary ammonium salt by adding a quaternizing agent, thereby imparting cationic properties to the surface of the emulsion particles at a high density. . General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼〔I〕 (However, R_1 in the formula is H or CH_3, R_2
is an alkylene group with 2 to 5 carbon atoms, R_3 and R_4 are H or an alkyl group with 1 to 5 carbon atoms, and A is ▲There are mathematical formulas, chemical formulas, tables, etc.▼or▲There are mathematical formulas, chemical formulas, tables, etc.▼ , R_1
, R_3, and R_4 are selected within a range in which the monomer is poorly soluble or insoluble in water. ) (4) A carboxyl-modified synthetic rubber latex or synthetic resin emulsion is used as a seed latex, and a monomer represented by the following general formula [I] or an ethylenically unsaturated monomer copolymerizable with these is added to the seed latex. Seed polymer obtained by addition polymerization of a mixture with [II]]. General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼〔I〕 (However, R_1 in the formula is H or CH_3, R_2
is an alkylene group with 2 to 5 carbon atoms, R_3 and R_4 are H or an alkyl group with 1 to 5 carbon atoms, and A is ▲There are mathematical formulas, chemical formulas, tables, etc.▼or▲There are mathematical formulas, chemical formulas, tables, etc.▼ , R_1
, R_3, and R_4 are selected within a range in which the monomer is poorly soluble or insoluble in water. ) (5) A carboxyl-modified synthetic rubber latex or a synthetic resin emulsion is used as a seed latex, and after neutralizing this seed latex to a pH of 6 or higher, the general formula [
A monomer represented by the following general formula [ I
] A method for producing a seed polymer, which is obtained by adding the monomer represented by the following in a proportion equal to or higher than the colloidal equivalent value (absolute value) of the seed latex, and then polymerizing the mixture using a radical polymerization initiator.