JPS609047B2 - Manufacturing method of polymer latex - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a latex of a polymer by adding an emulsifier and water to a solution of a polymer in an organic solvent, emulsifying the solution, and removing the organic solvent from the resulting emulsion.

Conventionally, polymer latexes other than naturally obtained natural rubber latexes have been produced and put to practical use exclusively by emulsion polymerization.

On the other hand, in recent years, advances in polymerization technology such as the amount of solution/machine have made it possible to obtain polymers with unique structures and physical properties.As a result, polymer latexes with such structures and physical properties are attracting attention. . A common method for obtaining these polymer latexes is to add an emulsifier and water to a polymer solution or a solid polymer dissolved in a suitable organic solvent to emulsify it. This method produces latex by removing the solvent from the resulting emulsion.

If the polymer content of the latex thus obtained is low, it may be concentrated by operations such as creaming, centrifugation, or water evaporation. However, when trying to obtain polymer latex using this method, polymer particles may aggregate or precipitate due to contact with heating parts when removing the solvent from the emulsion, or may not be obtained.・
There are problems such as the mechanical stability of the latex obtained by emulsion polymerization being significantly inferior to that of latex obtained by emulsion polymerization. In particular, poor mechanical stability makes it impossible to concentrate by centrifugation, and also causes many difficult problems when transporting the latex to end use. That is, when high mechanical shearing forces are applied to the relatively mechanically unstable latex thus obtained, it can be mixed with pigment bases, for example as paints and adhesives, when applied, and as pigments for paper processing. When compounding and coating, and when performing manpulling in the weaving and weaving fields, aggregates may be formed partially or, in severe cases, as a whole due to contact and fusion between latex particles. The latex itself may lose its functionality.

This tendency is particularly remarkable when mechanical shearing force is applied at high temperatures. The purpose of the present invention is to add an emulsifier and water to an organic solvent solution of a polymer to emulsify it, and remove the organic solvent from the resulting emulsion to produce a polymer latex. It reduces agglomeration and precipitation of coalesced particles, improves the mechanical stability of the resulting latex, enables centrifugal concentration if necessary, and improves the mechanical properties of the final product. This is an attempt to solve problems caused by physical stability.

The present invention uses {1} higher fatty acid salts as specific emulsifiers;
An anionic surfactant consisting of one or more selected from rosinate, dialkyl sulfosuccinate, alkylbenzene sulfonate, and mono- or dialkylnaphthalene sulfonate is added in an amount of 0.5% per part by weight of the polymer 10. to 15 parts by weight, [2] At least a part of which has two or more aromatic nuclei, and is bonded via (i) an aromatic nucleus of a fused ring system, or (ii) a heteroatom other than a carbon atom. Polymer 10 is a nonionic surfactant consisting of an ethylene oxide adduct of monophenols that do not have an aromatic nucleus.
The above object is achieved by using 0.5 to 15 parts by weight of latex in combination with silk, and the present invention makes it possible to easily produce latex with excellent mechanical stability. .

The polymer used in the present invention is soluble in organic solvents, substantially insoluble in water, and is formed by polymerizing one or more naturally occurring or polymerizable monomers. Polymers obtained by It may be a converted version.

Furthermore, a blend of two or more of these may be used. Examples of the polymer include the following.

Natural rubber, butadiene polymer, isoprene polymer, cyclobentadiene polymer, styrene-butadiene copolymer, styrene-isoprene copolymer, ethylene-propylene copolymer, ethylene-propylene-genes copolymer ( EPDM), isoprene-isobutylene copolymer, butadiene-acrylonitrile copolymer, ethylene polymer,
Examples include ethylene-vinyl acetate copolymer, butadiene-propylene copolymer, butadiene-ethylene copolymer, propylene polymer, butene polymer, and the like. Among these, the polymers particularly preferably used in the present invention are styrene-butadiene random or block copolymers, styrene-isoprene block copolymers, isoprene polymers, and ethylene-propylene diene copolymers. combination (EPDM), etc. These polymers may contain an oil extender or an oil-soluble plasticizer or softener.

As oil malleability and plasticity softeners, dioctyl phthalate,
Synthetic ester plasticizers such as dibutyl phthalate, diisodecyl phthalate, diisodecyl adipate, dioctyl sebacate, acetyl citrate, butyl stearate,
Paraffinic naphthenic and aromatic petroleum hydrocarbons having a boiling point of 200 points or more, and mixtures thereof;
Examples include natural or synthetic resins such as terbene resin, phenol resin, rosin resin, coumaron resin, and styrene resin, and modified products or mixtures thereof, and natural oils such as terbene oil and tall oil. The type of organic solvent used in the present invention is not particularly limited as long as it is substantially water-proof. Commonly used and preferred organic solvents include aliphatic, alicyclic, and
These are aromatic hydrocarbons or halides thereof, and a mixture of these may be used. However, when using a halide, it is particularly preferable to mix it with another solvent.
Further, the polymer solution in which the polymer used in the present invention is dissolved in an organic solvent may be a polymer solution obtained by solution polymerization, or a solid polymer dissolved in the above-mentioned organic solvent. It's okay.

The concentration of the polymer solution is not particularly limited, but is usually 5% by weight.
from 1 to 5% by weight, preferably from 1 to 4% by weight.

If it is less than 5% by weight, the productivity will be poor, and if it exceeds 5% by weight, the viscosity of the solution will increase significantly, making it difficult to prepare the solution itself, and furthermore, making the emulsification operation difficult, which is not preferable.

One or more anionic interfaces selected from higher fatty acid salts, rosinates, dialkyl sulfosuccinates, alkylbenzenesulfonates, and mono- or dialkylnaphthalenesulfonates, which are one component of the emulsifier used in combination in the present invention. Examples of activators include: As the higher fatty acid salt, those having 8 to 18 carbon atoms are preferred, and sodium salts and potassium salts of lauric acid, stearic acid, oleic acid, etc. are used. As the rosin acid salt, sodium salts, potassium salts, etc. of natural rosin acid and denatured disproportionated or hydrogenated rosin acids are used. The dialkyl sulfosuccinate is preferably one in which the alkyl group has 4 to 12 carbon atoms, and sodium dibutyl sulfosuccinate,
Sodium di(2-ethylhexyl)sulfosuccinate and the like are used. As the alkylbenzenesulfonate, those in which the alkyl group has 8 to 18 carbon atoms are preferably used, such as sodium dodecylbenzenesulfonate. As the mono- or dialkylnaphthalene sulfonate, those in which the alkyl group has 4 to 12 carbon atoms are preferred, and sodium dibutylnaphthalene sulfonate, sodium dibutylnaphthalene sulfonate,
Sodium dioctylnaphthalene sulfonate or the like is used. In the present invention, one or more of the above surfactants can be freely selected depending on the type of polymer to be emulsified and the type of solvent, but usually the solvent used is n-hexane or heptane. In the case of aliphatic hydrocarbons, higher fatty acid salts, dialkyl sulfosuccinates, toluene, alkylbenzene sulfonates, mono- or dialkyl in the case of aromatic hydrocarbons such as benzene. When naphthalene sulfonate, alicyclic hydrocarbon, or halogenated hydrocarbon is used, it is preferable to use a mixture of the two.

Rosinate is the preferred surfactant for all solvent systems. In the present invention, the amount of the anionic surfactant used is preferably 0.5 to 15 parts by weight, preferably 1 to 8 parts by weight, based on 10 parts by weight of the polymer.

If it is less than 0.5 parts by weight, emulsification will be insufficient, and if it exceeds 15 parts by weight, foaming will be severe during desolvation, and the viscosity will increase more than necessary, or the physical properties of the obtained latex in its final use may be affected, such as the formation of a film. This is undesirable because it causes deterioration in tensile properties and adhesive properties.

The other component used in combination in the present invention has two or more aromatic nuclei in at least a portion thereof, and includes (i) an aromatic nucleus of a condensed ring system, or (ii) a hetether other than carbon atoms.

It is a nonionic surfactant consisting of an ethylene oxide adduct of monophenols that do not have an aromatic nucleus bonded through atoms, and examples of the phenols include phenylphenol, benzylphenol, triphenol, Q- or 8-Pheni'lethylphenol, Pheni/Lev. Examples include ropi/lephenol, biphenylphenol, pendylthiophenol, phenylcresol, benzylcresol, Q- or 8-phenylethylcresol, phenylxylenol, polyphenylalkylphenol, and the like. Ethylene oxide can be added to these phenols using conventionally known methods, and one example is by blowing ethylene oxide into a toluene solution containing sodium hydroxide.

The amount of ethylene oxide added is determined by the HLB value (
HLB=E/5, E is the oxidized tyrene content (
%) is 6.7% to 16.7%, preferably 50% to 500% by weight based on 10% by weight of the phenol. This ethylene oxide addition portion may partially contain propylene oxide as a random or block copolymer. The nonionic surfactant, which is the second component constituting the emulsifier in the present invention, includes some of the above-mentioned F1. It may also contain nonionic surfactants other than ethylene oxide adducts of nols.

Examples include polyoxyethylene alkyl ether,
Examples include polyoxyethylene alkyl phenyl ether. The content of these nonionic surfactants that do not contain two or more aromatic nuclei in the total nonionic surfactants is preferably 5% by weight or less. The amount of the above-mentioned nonionic interfacial coating agent used in the present invention is 0.5 to 15 parts by weight, preferably 1 to 8 parts by weight, based on the weight of the polymer 10. If it is less than 0.5 parts by weight, emulsification will be insufficient, and if it exceeds 15 parts by weight, foaming will become severe during desolvation, and the viscosity will increase more than necessary, or the physical properties of the obtained latex in the final use may deteriorate, such as This is undesirable because it causes a decrease in the tensile properties, adhesive properties, etc. of the film.

The emulsifier used in the present invention is used by being dissolved in a polymer solution or in water before emulsification.

One of the preferable ways to add an emulsifier is when using a higher fatty acid salt or rosin acid salt, add the acid higher fatty acid or rosin acid to the polymer solution side, and add the base sodium hydroxide or lithium hydroxide. , potassium hydroxide, ammonia, triethanolamine, etc. are added separately to the water side to generate salt during emulsification. There is no need to limit the type of emulsifying machine for emulsifying the polymer solution, emulsifier, and water, and any known emulsifying machine may be used as long as it has a sufficiently strong emulsifying ability. Examples of emulsifiers that can be used include homomixers, homogenizers, and dispersants.
There are mills, colloid mills, etc., and two types of emulsifiers can be used in combination if necessary. The next step in the present invention is to remove the solvent from the emulsion obtained, which can be preferably carried out by heating through a jacket in an evaporator or by directly blowing steam, which is a common method for removing solvent. , a method other than the above-mentioned method, for example, Tokubuta 49-94002 (Tokukan Sho 51-2353), which precedes the present application.
There is also a method using a centrifugal thin film evaporator as shown in item 4).
Either method may be used.

In addition, when using latex, it may be preferable to leave some of the solvent, and in such cases, do not completely remove the solvent in the above solvent removal process. A portion of the latex may be left as is.The latex obtained in this way usually has a solid content concentration of about 5% to 65% by weight, but if necessary, it may be necessary to leave a part of the latex. Methods for obtaining concentrated latex include creaming, centrifugation, and water evaporation, and concentration using a centrifuge is particularly efficient and highly reproducible, so it is preferred. By carrying out the present invention, no matter which concentration method is used, agglomeration and precipitation of latex particles are extremely small and concentration can be easily achieved.The concentrated latex obtained by the present invention can be used for dip molding products, foam rubber, etc. It can be used in a wide range of applications, including rubber thread, processed thread, force bed sizing agent, fiber processing agent, surface coping agent, various adhesives, paints, binders, asphalt with Hupux added, and cement compounding agents.

The present invention will be explained in more detail with reference to some examples below, but these are not intended to limit the invention. Example 1 2 parts by weight of disproportionated rosin acid and 10 parts by weight of phenylphenol in a 2% by weight toluene solution containing 10 parts by weight of a thermoplastic rubber produced by solution polymerization of styrene and butadiene (Soprene T414) 3 parts by weight of a compound to which 15 parts by weight of ethylene oxide has been added are added and mixed and dissolved, and this solution and an aqueous solution in which an equimolar amount of sodium hydroxide is dissolved in the disproportionated rosin acid are mixed in a weight ratio of 1. They were mixed at a ratio of .5:1 and emulsified using a disper mill.

The generated emulsion containing toluene is immediately sent to a toluene removal tank equipped with a heating jacket, and heated with steam to evaporate and remove toluene, resulting in a solid content concentration of 37.
A dilute latex of 5% by weight was obtained. This was sent to a cylindrical centrifuge and operated at about 12,000 revolutions (about 600 revolutions) to obtain a concentrated latex (solid content concentration 56.5% by weight). The amount of copolymer coagulation and precipitation in the step of removing toluene by evaporation and the step of concentrating by centrifugation was 0.2% by weight or less. In addition, the mechanical stability of the obtained concentrated latex at room temperature (according to the method of JIS K-6381) is 180 Nasha or higher, and the mechanical stability at high temperature (according to JIS K-6381 method) is 180 or more.
・Apply the method of K-6381 at 70o0. ) is 120
It was sand. Comparative Example 1 As an emulsifier, polyoxyethylene phenol ether used in Example 1 was replaced with oxyethylene having a polymerization degree of 1.
A concentrated latex (solid content: 54.4% by weight) was obtained by the same procedure as in Example 1 except that polyoxyethylene nonylphenyl ether of No. 4 was used.

The amount of copolymer aggregation and precipitation in the step of evaporating and removing toluene and the step of concentrating by centrifugation is 1. % by weight. The mechanical stability of the obtained concentrated latex was 120 sand at room temperature and 15 odd at a high temperature of 70°C. Example 2 Butadiene-styrene-butadiene-styrene block copolymer (molecular weight 7
0000, bound styrene content 40% by weight) in a 3% by weight toluene solution containing 1.5 parts by weight of disproportionated rosin acid.
2 parts by weight of a compound prepared by adding 15 parts by weight of ethylene oxide to 10 parts by weight of Q-phenylethylphenol are mixed and dissolved, and the solution is mixed with water in an equimolar amount as that of unfiltered rosin acid. An aqueous solution containing dissolved sodium oxide was mixed at a weight ratio of 2:1, and the mixture was emulsified using a disper mill.

By evaporating and removing toluene from the produced emulsion containing toluene, the solid content concentration is reduced to 50. A concentrated latex of neck weight % was obtained. The amount of agglomerated and precipitated block copolymer in the solvent removal process is 1. % by weight. Moreover, the mechanical stability of the obtained concentrated latex was 180 daughter sand or more at room temperature and 1800 seconds or more even at high temperature (70oo).

Example 3 A latex was produced in the same manner as in Example 2 except that the following emulsifier was used in place of the emulsifier system used in Example 2.

The results obtained are shown in Table 1. A'1} 2 parts by weight of disproportionated sodium rosinate.

'21 3 parts by weight of a compound obtained by adding 300 parts by weight of ethylene oxide to 10 parts by weight of phenylcresol. Bm Sodium dibutylnaphthalene sulfonate 2 parts by weight.

'2} 3 parts by weight of a compound obtained by adding 100 parts by weight of ethylene oxide to 10 parts by weight of biphenylphenol.

C'1} 2 parts by weight of sodium dioctylnaphthalene sulfonate.

3 parts by weight of a compound prepared by adding 20 parts by weight of ethylene oxide to 100 parts by weight of di(Q-phenylethyl)phenol.

D{1 Cor 2 parts by weight of disproportionated sodium rosinate.

[3 parts by weight of a compound prepared by adding 30 parts by weight of ethylene oxide to 100 parts by weight of 2'di(Q-phenylethyl)phenol. E[1=l 2 parts by weight of disguised sodium dinate.

[Compound 3 in which 20 parts by weight of ethylene oxide is added to 10 parts by weight of 2'tri(Q-phenylethyl)phenol
Weight part. 2 parts by weight of NI'potassium oleate.

{21 Compound 3 prepared by adding 20 parts by weight of ethylene oxide to 10 parts by weight of tri(Q-phenylethyl)phenol
Weight part.

Comparative Example 2 A latex was produced in the same manner as in Example 3, except that the following emulsifier was used in place of the emulsifier system used in Example 3.

The results obtained are shown in Table 1. G 5 parts by weight of disproportionated sodium rosinate.

H 3 parts by weight of a compound prepared by adding 200 parts by weight of ethylene oxide to 100 parts by weight of tri(Q-phenylethyl)phenol.

1 (11 2 parts by weight of sodium dioctylnaphthalene sulfonate.

[2] 3 parts by weight of a compound prepared by adding 20 parts by weight of ethylene oxide to 100 parts by weight of nonylphenol.

Table 1 Experimental results (Example) 3 and Comparative example 2) Example
4 1% by weight hebutane solution containing 10 parts by weight of ethylene-propylene-ethylidenenorbornene terpolymer rubber having a Mooney viscosity (M oC) of 65 (Mitsui EPT3070, manufactured by Mitsui Petrochemical Industries, Ltd.) 5 parts by weight of sodium dioctyl sulfosuccinate and 3 parts by weight of a compound prepared by adding 20 parts by weight of ethylene oxide to parts by weight of di(Q-phenylethyl)phenol io were added and mixed and dissolved, and the solution and water were mixed in a weight ratio. They were mixed at a ratio of 1:1 and emulsified using a disper mill.

The produced emulsion containing hebutane was immediately sent to a hebutanization tank equipped with a heating jacket, and the hebutane was evaporated off by heating. At this time, some of the water evaporated together with hebutane to obtain a dilute latex with a solid content concentration of 11.5% by weight. This was fed into a cylindrical centrifuge and operated at about 10,000 revolutions (about 500 rpm) to obtain a concentrated latex (solid content: 53.2% by weight). The amount of copolymer coagulated and precipitated in the step of removing hebutane by evaporation and the step of concentrating by centrifugation was 2.0% by weight. Moreover, the mechanical stability of the obtained concentrated latex was 180 or more than sand at normal temperature, and the mechanical stability at high temperature of 70 qo was 900 seconds. Comparative Example 3 An attempt was made to obtain latex by using only 8 parts by weight of sodium dioctyl sulfosuccinate as an emulsifier and performing the same operation as in Example 4, but most of the copolymer aggregated during the centrifugation operation. , manufacturing was impossible.

Example 5 Polyisoprene rubber with Mooney viscosity (M Hinase 2qC) of 78 (Cariflex IR305, manufactured by Shell Chemical ■) 1
Add 3 parts by weight of a compound prepared by adding 20 parts by weight of ethylene oxide to 4 parts by weight of unshielded rosin acid and 10 parts by weight of di(Q-phenylethyl)phenol to a 10% by weight benzene solution consisting of 0 parts by weight. A concentrated latex with a solid content of 56.2% by weight was obtained in the same manner as in Example 1.

The amount of coagulation and precipitation of the polymer in the step of evaporating and removing benzene and the step of total concentration by centrifugation is 2.5% by weight, and the mechanical stability is higher than 180% at room temperature and at high temperatures (70%). It was 150 calm sand.

Comparative Example 4 A concentrated latex with a solid content concentration of 57.3% by weight was obtained by using only 7 parts by weight of disproportionated sodium rosinate as an emulsifier, and otherwise performing the same operation as in Example 5.

The amount of coagulation and precipitation of the polymer in the step of evaporating and removing benzene and the step of concentrating by centrifugation was 5.0% by weight,
The mechanical stability was 150 inkstone sand at room temperature and 60 sand at high temperature 70 oo. Example 6 The thermoplastic elastic body used in Example 1 (Solprene T414
) 50 parts by weight of naphthenic oil (viscosity specific gravity constant VGC: 0.870) was added to a 2% by weight toluene solution containing 10 parts by weight and uniformly mixed and dissolved.

The rest was the same as Example 1, solid content concentration 55.4% by weight.
A concentrated latex was obtained. The amount of coagulation and precipitation in the step of evaporating and removing toluene and the step of concentrating it by centrifugation is 4.
0% by weight, and the mechanical stability is 180 town seconds at room temperature.
As mentioned above, at high temperature (70 qo), it was 132 town sand. Comparative Example 5 A concentrated latex with a solid content concentration of 58.2% by weight was obtained in the same manner as in Example 6 except that the emulsifier of Comparative Example 1 was used as the emulsifier.

The amount of coagulation and precipitation in the step of evaporating and removing toluene and the step of concentrating by centrifugation was 4% by weight, and the mechanical stability was 60% by weight at room temperature and 12% by weight at high temperature (70qo). Example 7 A latex was produced using the same emulsifier and operation as in Example 2, except that the following polymer was used in place of the polymer used in Example 2.

The results obtained are shown in Table 2. 1 Butadiene-styrene block copolymer (manufactured by Kraton 1101 Shell Chemical)
0 Isoprene-styrene block copolymer (manufactured by Kraton Li07 Shell Chemical Co., Ltd.) m Butadiene-styrene block copolymer (manufactured by Kraton 1101 Shell Chemical Co., Ltd.) and polybutadiene rubber with a Mooney viscosity (M ratio C) of 35 Comparative Example 6 Example 7 except that the emulsifier of Comparative Example 1 was used as the emulsifier.
A latex of the 1, 0, m copolymer shown in Example 7 was produced in the same manner as above.

The results obtained are shown in Table 2. Table 2 Experimental Results (Example 7 and Comparative Example 6) As is clear from Examples 1 to 7 and Comparative Examples 1 to 6, the present invention has a step of removing the solvent and a process of centrifugation compared to the conventional method. agglomeration during the concentration process,
The amount of precipitation can be reduced.

Claims (1)

[Claims] 1. When producing a latex of a polymer by adding an emulsifier and water to an organic solvent solution of the polymer and removing the organic solvent from the resulting emulsion, (1) higher fatty acid salts and rosinate salts are used as emulsifiers. , dialkyl sulfosuccinates, alkylbenzene sulfonates, and mono- or dialkylnaphthalene sulfonates.
0.5 to 15 parts by weight, (2) at least a part of which has two or more aromatics, (i) an aromatic nucleus of a condensed ring system, or (ii) a hetero non-carbon atom A mechanical method characterized by using 0.5 to 15 parts by weight of a nonionic surfactant consisting of an ethylene oxide adduct of monophenols that do not have an aromatic nucleus bonded through atoms, based on 100 parts by weight of the polymer. A method for producing a polymer latex with excellent stability.