JPS6094404A - Production of vinyl polymer latex - Google Patents

Abstract

PURPOSE:To produce the titled latex having uniform and relatively large particle diameter, by initiating the polymerization of a vinyl monomer using a nonionic surface active agent as an initial emulsifier, and carrying out the polymerization adding an anionic surface active agent to the system. CONSTITUTION:A vinyl monomer (e.g. vinyl chloride) is incorporated with preferably 0.1-1.0wt% (based on the monomer) of a nonionic surface active agent having an HLB value of preferably 13-17 (e.g. polyoxyethylene nonylphenyl ether) to start the emulsion polymerization. When the polymerization degree reaches preferably 5-20%, the polymerization is continued while adding preferably 0.3-0.7wt% (based on the monomer) of an anionic surface active agent (e.g. dodecylbenzenesulfonic acid sodium salt) to the reaction mixture to obtain the objective latex. USE:Comparative standard substance for electron microscope, carrier for diagnostic reagent, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a stable vinyl polymer latex having uniform particle size. More specifically, it is a stable vinyl product with a large particle size and a narrow particle size distribution, which is characterized by starting polymerization using a nonionic surfactant as an initial emulsifier, and then polymerizing while adding an anionic surfactant. The present invention relates to a method for producing polymer latex.

Conventionally, methods for producing stable polymer latexes with relatively large and uniform particle diameters include (1) reducing the amount of emulsifier used as the specific surface area decreases as the particle size increases; Emulsion polymerization method (2) Fine polymer particles with a uniform particle size, which have been adjusted in advance by a normal emulsion polymerization method, are charged as seed particles into a polymerization tank together with water, 1 polymerization initiator, and initial monomers, and polymerization is carried out using start,
A so-called seed emulsion polymerization method is known in which monomers and emulsifiers are supplied while being kept to the necessary minimum according to the growth of particles as the polymerization progresses, and polymerization is carried out while suppressing the generation of new particles. However, in the former method (1), the polymerization is unstable because the amount of emulsifier is small, and the latex particles obtained are relatively small, and even if they are large, they are only 0.
It is said that the limit is about 5 (μ). In addition, although the latter method has been applied industrially in various fields,
It is not necessarily an advantageous method, as it is a stepwise polymerization, which complicates the manufacturing process and requires special techniques for the monomer charging method.

Another method is (3) to carry out the polymerization in the presence of a water-insoluble soap as the sole emulsifier at the beginning of the polymerization, and then, when the monomer has been converted to a certain extent into polymer particles, to start adding the water-soluble emulsifier. A method of obtaining polymer latex with uniform particle size by polymerizing by
No.) is known.

However, method (3) uses water-insoluble soap at the initial stage of polymerization, making it difficult to adjust the initial emulsifier, and this polymerization method yields a polymer with a large particle size of 0.5 (μ) or more. There are disadvantages in that it is not possible to control the desired particle size freely.

As a result of intensive research to solve these drawbacks, the present inventors have found that a nonionic surfactant is used as an initial emulsifier, and after the start of polymerization of vinyl monomers, an anionic surfactant is added while polymerization is carried out. By doing this, a polymer latex with an unprecedented particle size and narrow particle size distribution can be obtained in one step of polymerization, and the desired particle size can be freely adjusted using a nonionic surfactant. They found a method that could control this and completed the present invention.

Any conventionally known nonionic surfactants can be used as the nonionic surfactant used in the present invention, and among these, mopholyoxyethylene alkylphenyl ethers and polyoxyethylene alkyl ethers are used.

Polyoxyethylene bitane alkyl esters.

Polyoxyethylene fatty acid esters and mixtures thereof, such as polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, Polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene laurate, polyoxyethylene stearate.

Polyoxyethylene oleate and mixtures thereof are effective, and among these, those with an HLB value of 10 to 19 are particularly preferred, and
It is desirable to use a nonionic surfactant with an LB value of 13 to 17. The amount of nonionic surfactant used is
001 to 5% by weight based on the monomer charged, preferably α
It is used in an amount of 05 to 2.0% by weight, but in order to carry out the polymerization reaction more stably, it is more preferably used in an amount of 11 to 1.0% by weight.

In this way, in the present invention, the type of nonionic surfactant and the amount used play an important role in determining the particle size of the polymer latex produced, and by selecting these appropriately, the particle size distribution can be narrowed and Moreover, it becomes possible to freely produce a polymer latex having a desired average particle diameter, for example, 0.6 (μ) or more.

On the other hand, if only a nonionic surfactant is used as an emulsifier in the entire polymerization reaction, the latex becomes unstable as the polymerization reaction progresses and tends to cause agglomeration, until the polymerization rate K is high enough to be advantageous for practical use. It is difficult to carry out the polymerization reaction stably. In the present invention, after initiating polymerization of vinyl monomers in the presence of a nonionic surfactant and a polymerization initiator, when adding an anionic surfactant to the polymerization system, a new polymer, which is often experienced during polymerization, is added. The required amount is added to the polymerization system so that there is no free emulsifier present which would cause particle formation. What is important in carrying out the present invention is that the surfactant added after the initiation of polymerization of the vinyl monomer must be an anionic surfactant, which is an essential requirement of the present invention. It is. If a nonionic surfactant is used instead of this anionic surfactant,
The desired stabilizing effect cannot be obtained, and the object of the present invention cannot be achieved. If the anionic surfactant is added too much, new particles will be generated in the polymerization system, making it difficult to obtain the desired uniform large particle size. Stabilizing effect cannot be obtained.

Therefore, the anionic surfactant needs to be added when the polymerization rate reaches 1 to 30, preferably 5 to 20, after polymerization starts under the nonionic surfactant polymerization initiator. There is. The method of adding the anionic surfactant is not particularly limited, and a predetermined amount may be added in portions or continuously. After the initiation of polymerization, the amount of anionic surfactant added to the system is 01 to 3% by weight, preferably 0.3 to α
It is desirable to add 7% by weight.

As the anionic surfactant added after the initiation of polymerization, conventionally known anionic surfactants can be used without any restriction. For example, alkyl fatty acid salts with straight-chain and branched alkyl substituents, aryl substituents, vinyl substituents.

Alkyl sulfate ester salt, alkylbenzene sulfonate, alkylnaphthalene sulfonate, dialkyl sulfosuccinate, alkyl (tallow) methyl taurate,
Alkyl phosphate, polyoxyethylene alkyl ether sulfate, polyoxyethylene alkylphenol ether sulfate, naphthalene sulfonic acid formalin condensate,
Polystyrene sulfonic acid sodium salt etc. are used.

As the vinyl monomer to be subjected to the polymerization of the present invention, any vinyl monomer having a single polymerizable C1=C<or ij: OH,=C- group can be used. Representative examples of such monomers include vinyl chloride, vinyl bromide, vinylitine chloride, hnylidene bromide, chlorotrifluoroethylene, 112-
Vinyl halides such as dichloroethylene, vinyl esters such as vinyl globionate, vinyl butyrate, and vinyl benzoate, acrylates such as methyl acrylate, phenyl acrylate, methyl methacrylate, and phenyl methacrylate, styrene, and vinyl toluene.

Vinyl aromatic monomers such as vinylnaphthalene, monoolefins such as ethylene, propylene, cyclohexene,
Vinyl ethers such as vinyl methyl ether, vinyl amyl ether, and vinyl phenyl ether; vinyl cyanides such as nitrile, methacrylonitrile, and vinylidene 77; alpha beta such as acrylic acid, methacrylic acid, maleic acid, and itaconic acid. These include olefinically unsaturated carboxylic acids and anhydrides, and al7aveta olefinically unsaturated amides such as acrylamide and methacrylamide. Particularly preferred vinyl monomers in the present invention are vinyl chloride, vinylidene chloride, vinyl acetate methyl methacrylate, styrene, and mixtures thereof.

As the polymerization initiator, conventionally known water-soluble polymerization initiators such as potassium persulfate and ammonium persulfate can be used without particular limitation.

In carrying out the present invention, the polymerization reaction is carried out under atmospheric pressure or increased pressure at a temperature in the range of 30 to 80 DEG C., where polymerization is normally carried out. Polymerization temperature generally does not affect the particle size of the product, but lower temperatures give higher molecular weight products and higher temperatures give lower molecular weight polymers.

Since the polymer latex obtained by the present invention has a relatively large and uniform particle size, it can be used as a comparative standard material for (a) microscopy microscopes (b) particle counters (c) light scattering models, etc., and as a diagnostic reagent. By adsorbing various antigens and antibodies onto latex particles and utilizing an agglutination reaction, it can be used as a diagnostic reagent for various tests such as rheumatoid arthritis, pregnancy diagnosis, and protein detection. Furthermore, by carrying out seed emulsion polymerization using the polymer latex obtained in the present invention, it is also possible to obtain polymer particles with a larger particle size and more uniform particle size than in conventionally known methods.

The present invention makes it possible to easily and inexpensively provide a polymer latex that meets these purposes.

The effects of the present invention will be made more specific and clear by the following examples, but the present invention is not limited to these examples.

Example 1 Eleven glass autoclaves equipped with a buckle stirrer and pressure gauge were charged with the following ingredients.

Vinyl chloride 100 parts by weight Ion exchange water 100
17) [1,4tt Potassium Persulfate [L07// Before adding vinyl chloride monomer to the reactor, the air inside was completely replaced with nitrogen. Polymerization reaction is 500 r
The reaction was carried out at 64° C. with pm stirring. Separately, 0.3 parts by weight of sodium dodecylbenzenesulfonate was dissolved in ion-exchanged water and prepared, and after the start of polymerization, addition was started when the polymerization rate reached 10%. Then, the reaction mixture was taken out at every fixed polymerization rate and the surface tension was measured. From this surface tension value, the optimum amount of emulsifier to be added to the polymerization reaction, necessary to stabilize the particles without generating new particles, was calculated and added to the reaction mixture. Polymerization was terminated when the vinyl chloride monomer in the system was sufficiently consumed and the pressure began to decrease. Subsequently, unreacted vinyl chloride monomer was separated by degassing operation. The solid content of the obtained latex was 36. j%.

The average particle size was CL62 (μ). When the particle size distribution state of the latex obtained under the above conditions was measured using a Coulter counter and an electron micrograph, it was found that the standard deviation was +0.
The latex had an extremely uniform particle diameter of 01 (μ). FIG. 1 illustrates the particle size distribution obtained by the simultaneous centrifugal sedimentation method (DISCC TRIFUGE kite ■).

Example 2 A polymerization reaction was carried out under the same conditions as in Example 1, except that the same polyoxyethylene nonylphenyl ether as in Example 1 was used and the amount used was varied. The result is the first
Shown in the table.

Table 1 Test number Charge amount (wt%) Solid content (%) Polymerization rate (chi) Average particle size ω) #Semi-deviation 1 α05 3a3 74
．． 2 (18010520,15&?77.4 α7
2 0.023 α2 5&7 HL6 (1650,
024α5 55.5 74.5 0.65 α015
α4 (Example 1) 541 75.0 0.62 α
016 1.0 54.5 758 0,51 0.0
1 Example 3 A polymerization reaction was carried out under the same conditions as in Example 1 except that polyoxyethylene nonylphenyl ethers having different HLB values were used as nonionic surfactants and the amount added was changed. The results are shown in Table ①.

Table ■ Test number HLB value Solid outside (chi) Polymerization rate (%) Average particle size 01) Standard deviation 115551L7 75.0
α76 0.022 14, + 51>9 7a7 α
71 α02! S 17.056175.0 0.62
0.01 Example 4 As a nonionic surfactant, polyoxyethylene sorbitan monolaurate α2-fold f! The polymerization reaction was carried out under the same conditions as in Example 1, except that 0.3 parts by weight of sodium iouryl sulfate was used as the anionic surfactant. The solid content of the obtained latex was 3! L4chi, average particle size 08
0 (μ), and the standard deviation of the particle size is 0.02 (μ)
Met.

Example 5 Polymerization reaction was carried out under the same conditions as in Example 1, except that 02 parts by weight of polyoxyethylene 2-uryl ether was used as the nonionic surfactant and 03 parts by weight of potassium lauryl carboxylate was used as the anionic surfactant. I did it. The solid content of the obtained latex was 554 cm, the average particle size was α78 (μ), and the standard deviation of the particle size was 0.001 (μ).

Example 6 A polymerization reaction was carried out under the same conditions as in Example 1, except that 5 parts by weight of vinyl acetate monomer was added before adding vinyl chloride monomer. The solid content of the obtained latex was 35.9 inches, the average particle size Q was 650 (μ), and the standard deviation of the particle size was α001 (μ).

Comparative Example 1 Only the following components were charged into a 11 glass autoclave without using an anionic surfactant.

Vinyl chloride 100 Ion exchange water 100 Porioxyethylene nonylphenyl ether [ll4
Potassium persulfate 0.07 tt Before adding the vinyl chloride monomer to the reactor, the air was sufficiently replaced with nitrogen. Polymerization reaction iJ was carried out at 64° C. with stirring at 30 rpm. It agglomerated 6 hours after starting offshore.

Comparative Example 2 The following components were charged all at once into a 11 glass autoclave.

Vinyl chloride 100 parts by weight Ion exchange water 100
0.2〃 Sodium tribenzene sulfonate 0.3〃
Potassium Persulfate 0.07 The reactor was completely purged of air with nitrogen before adding the vinyl chloride monomer. The polymerization reaction was carried out at 64° C. with stirring at 300 rpm. Eight hours after the start of polymerization, the pressure in the system began to decrease and the polymerization was considered to have ended.

Unreacted vinyl chloride was separated by a degassing operation.

The solid content of the obtained latex was 42.5%, and the average particle size was 0.09 (7z).

[Brief explanation of drawings]

FIG. 1 shows the particle size distribution of the latex obtained in Example 1. Patent applicant: Toyo Soda Kogyo Co., Ltd. Ta stomach Figure 1 0 0.2 0.4 0.6 0.8 Particle size (ll)

Claims (5)

[Claims] (1) Stable, uniform and large particle size characterized by starting the polymerization of vinyl monomers in the presence of a nonionic surfactant and a polymerization initiator, and then polymerizing while adding an anionic surfactant. A method for producing vinyl polymer latex. (2) The manufacturing method according to claim 1, wherein an anionic surfactant is added when the polymerization rate of the vinyl monomer reaches 1 to 30%. (3) Claim 1, in which the amount of anionic surfactant added is 01 to 3% by weight based on the vinyl monomer charged.
The manufacturing method described in item 1 or 2. (4) The manufacturing method according to claim 1, wherein the amount of the nonionic surfactant added is 14.0.01 to 5 times the amount of the charged vinyl carrier-II-4 tV. (5) The manufacturing method according to claim 1 or 4, wherein the nonionic surfactant has an HLB value of 10 to 19.