SU852879A1 - Method of improving stable polymeric latexes - Google Patents

Description

one

The invention relates to the field of producing thin aqueous polymer latexes, used as adhesives, polymeric binders in aqueous emulsion paints, for impregnating paper, etc. When using .latexes for the indicated purposes, high demands are placed on them. Latexes must be stable during storage and transportation, especially in winter. Freezing and subsequent thawing usually results in a coagulation of la, tex. Latexes used to prepare water-based paints should be resistant to the action of VIS of various additives, including electrolyte additives. Latexes used to impregnate paper used in the production of laminated plastics, in addition to resistance to the effects of low temperatures and electrolytes, should also have a high impregnating ability.

However, latex, obtained at present in the presence of anionic surfactants, have low impregnation capacity, since both latex particles and

wet paper has a negative charge.

A method is known for producing polymer latexes with positively charged particles and high stability by emulsion copolymerization of vinyl aromatic monomers, dieno and unsaturated carboxylic acids in the presence of sodium dodecyl sulfate emulsifier and ammonium persulfate initiator. However, to obtain a sufficiently high charge density, it is necessary to use an unsaturated carboxylic acid in an amount of at least 30% of the total weight of the monomer charge. The high content of carboxyl groups in the copolymer makes the polymer brittle, and therefore such a polymer latex can not be used as a binding agent for paints, as an impregnating material or ly adhesive.

There is also known a method for producing aqueous latexes of polyacrylates, poly25 methacrylates and polybutadiene by emulsion copolymerization of the corresponding monomers in the presence of a water-soluble initiator potassium or ammonium sulfate and an emulsifier-hydrolyzed alkali metal copolymer of vinyl acetate and olefinsulfonate. The latexes produced by this method are characterized by increased storage stability and resistance to freezing (before) and subsequent thawing.

However, the resistance of these latexes to the effect of low temperatures is insufficient when they are used as binders for paints, in areas with harsh climatic conditions. In addition, these latexes are unsuitable for the preparation of cellulosic materials, since their particles also have a negative charge.

A known method for producing stable polymer latexes by emulsion copolymerization of vinyl monomers with an unsaturated compound chloroprene in the presence of a cationic surfactant of a quaternary ammonium salt and a peroxide initiator (3}.

A mixture of potassium persulfate with a salt of disproportionate abietic acid or a fatty acid salt is used as an initiator system. As an emulsifier, a non-ionic emulsifier — eukoxyoxyethylene glycol monostearate C „COO (0) H, is used with subsequent introduction into the finished latex 3–10 parts by weight per 100 parts by weight. Betaine polymer of general formula RC (0) NH (CH2) N (CH) 2COO The latexes obtained according to the indicated method are stable and retain at least threefold cooling to -30 ° C and subsequent heating to 20 ° C. Latex particles, due to the introduction of betaium, acquire a positive charge.

The disadvantages of this method are the following:

copolymerization cannot be carried out under the specified conditions until complete conversion, as a result of which subsequent stripping of the residual monomer from the finished latex is required

a multicomponent stabilizing system (anionic emulsifier, non-ionic surfactant, betaine) is used, the components of which are introduced into the latex at various stages of the process, which also complicates the technology for producing latex;

it is necessary to use significant amounts of stabilizers (total amount up to 20 parts by weight per 100 parts by weight of polymer);

the frost resistance of latexes (-30 ° C) is still insufficient when operating them in places with harsh climatic conditions.

The aim of the invention is to simplify the technology, as well as to increase the stability of latexes to the action of electrolytes and low temperatures.

This aim is achieved in that in the method for producing stable polymer latexes by emulsion copolymerization of vinyl monomers with the unsaturated compound in the presence of the cationic surfactant - a quaternary ammonium salt and the peroxide initiator, as a quaternary ammonium salt of alkyl- or use dialkilarilpolioksietilenoksimetilmetildietilammoniybenzosulfonata general formula

jJR-f OCH-jCH2) n OCH2-N (C2H5) 2CH3 CeHjSOj

15 where R - a / l - "l - CijH.j5-3jgH57) or

9 (g

dialkylary ;: -CdNgeChO)

about

in the amount of 3.4-6.0% by weight of the monomers, and 1- (QS-alkyl acrylate-1-tert-butylperoxyethane in the amount of 0.5-4.8% by weight of the monomers) is used as the unsaturated compound and at the same time peroxide initiator.

The said alkylpolyoxyethyleno-xymethylmethyl-diethyl ammonium benzene sulfate is a mixture of compounds substituted by the groups Hjg, Hy, the separation of which in individual substances is difficult. In the proposed method of producing stable latexes, this compound is used in the form of a mixture containing approximately equally each of the compounds.

The process should be carried out in two stages. In the first stage, a shutter latex is obtained by copolymerizing vinyl monomers with l- (ct-alkyl acrylate) -1-tert-butylperoxyethanes.

CH C-C-o-dH-0-o-c (CH,) j,

T about en

where R is alkyl CHj-CgH. In the second stage, emulsion copolymerisation of the vinyl monomers on the seed latex is carried out, while the copolymerization is carried out under the action of the peroxide groups of the copolymer obtained in the first stage.

According to the proposed method, the emulsion copolymerization of vinyl monomers is carried out at a SO-EO temperature with and the ratio of monomer and water phases is 1: 3-1: 1.5. The copolymerization process, depending on the reaction conditions and the type of vinyl monomers, is completed in 2-6 hours, with the polymer yield reaching 98.599, 5%.

As vinyl monomers, in the preparation of latexes, for example, styrene, acrylic and methacrylic esters or acrylonitrile can be used. The proposed method is illustrated by the following examples. Example 1. In a reaction vessel equipped with a stirrer and reflux condenser, ToyCxoft is fed with 300 ml (298.5% of the total weight of water monomers) and 6 g (5.97% of the total weight of monomers) of a cationic surfactant for feeding inert gas. which is a mixture of .hexadecyl-, heptadecyl, and octadecyldioxyethylenoxymethylmethylethylammonium benzene sulphonates of the structural formula 1.nH1oO "aaa), c ,, H., 5-todH CK ,, l5oeH, i-KriH, (C, H5) 5cib BW . , tocH3CH ,, ociK ,, - NCi (djH5Vie Hb $ o) After the surfactant is dissolved and the solution is heated to 90 ° C, 10 g (9.95% of the total monomer mass) of styrene and 0.5 g (( 0.49% of the total weight of the monomers) 1-methacrylate-1-tert-butyl peroxyethane with the structural formula: snrnn, c; -c-o-cn-o-o-C (sn,) 2 and carry out the copolymerization in for 1.5 hours at a temperature of 90 ° C. After that, 90 g (89.55% of the total monomer mass) of styrene are charged and the process is still 4.5 hours long. The process is carried out with a continuous flow of inert gas. The copolymer yield is 98.9%. Average latex diameter cha 0.19 t 0.02 µm. Latex does not coagulate with the introduction of 20 parts by weight of sodium sulfate per 100 parts by weight of copolymer. the technology described in Example 1. 300 (294%) parts by weight of water and 6 parts by weight (5.9%) of 2,4-dinonylphenyldecaoxyethylene-oxymethyl-diethylammonium benzene sulfonate of the structural formula are loaded into the reactor.

СЭН19- Ч 6 (, oOCtt2-N lH5 ((J2H5) 2

5 ma.ch. (4.9%) styrene, 2 ma.h. (1.9%) 1- (ot-amylacrylate) -1-tert-butyl peroxoethane and carry out the process for 1.5 hours. Then 95 wt.h. (93%) styrene and continue to polymerize another 3.5 hours

The output of the copolymer of 98.6%. The average diameter of the latex pieces is 0.17 + i 0.02 microns. Latex does not coagulate with the introduction of 40 mache. on.

CgHis- -f OfiH CHj toOdHj-KCHsitijUgU

10 ma.ch. (9.5%) of methyl methacrylate, 5 wt.h. (4.8%) 1- (oC-ethyl acrylate) -1-tert-butylperoxyethane and lead at Boos for 1 hour. Then, 90 wt.h. (85.6%) of methyl methacrylate and the polymerization is continued for another 3 hours.

The output of the copolymer of 99.5%. The average diameter of latex pieces 0.121 0.1 microns

100 ma.ch. copolymer. Latex endures 5 freezing cycles with defrosting without forming a coagulum.

Example 3. The process is carried out according to the technology described in Example 1. 150 mouch is charged to the reactor. (143 water, 3.6 wt.h. (3.4%) 2,4-dinonylphenylykozoyoxyethylenemethylmethylethylammonium benzene sulfonate, structural formula

Latek does not coagulate upon administration of 20 n. Na7.SOi, per 100 mah. copolymer. The latex maintains without freezing coagulum 5 cycles of freezing to -50 ° C, followed by thawing.

Example 4. The process is carried out according to the technology described in example 1. A load of 150 mas is loaded into the reactor.

(145.5%) of water, 6 ma.ch. (5.8%) 2,4-dinonylphenyldecaoxyethyleneoxymethyl, -bdN d

dgliig- О) 40Ш, SI2) 100СЫ, -ТСС115 (CsHslz БЫ5

10 ma.ch. (9.7%) of butyl acrylate, 3 ma.ch. (2.9%) 1-methyl acrylate-1-tert-butyl peroxoethane and conduct the process at 60 ° C for 1 h. Then load 90 m.h. (87.3%) of butyl acrylate and continue eopolymerization more than 1.5 hours. The yield of eopolymer is 99.1%. The average diameter of the latex pieces is 0.16 and 0.01 microns. Lateck-does not coagulate with the introduction of 40 mache. on 100 ma.ch. eopolymer. Latek CgHis c9Ht9- - (, CHi) (oOfiKj

16 ma.ch. (15.2%) styrene, 4 wt. (3.8%) butyl acrylate, 5-ma.h. (4.8% of 1-methacrylate-1-tert-butylperoxyethane and carry out the process at BS-C for 1.5 hours. Then, 64 masses of hours (60.9%) of styrene are charged, 16 masses of hours, ( 15.2%) of butyl acrylate and continue eopolymerization for another 3.5 hours. The copolymer yield is 99.2%. The average diameter of the latex parts is 0.09 0.01 μm. The latex does not coagulate upon the introduction of 40 wt.

Cghig

fjHia- W oOHjCHj ipOCHj-NCHj () 2 ifiHs Oj5 ma.ch. (4.9%) styrene ,. 5 ma.ch. (4.9%) butyl acrylate, 3 ma.ch. 42.9%) of 1-methacrylate-1-tert-butyl peroiethane and lead for 1 hour. Then load 45 m.ch. (43.7%) Etirol, 45 mph. (43.7%) of Io butyl acrylate continue eopolymerization for another 2 hours. The yield of copolymer is 98.5%. The average diameter of latex particles is 0.15 ± 0.01 microns. em with the introduction

9 ma.ch. (8.7%) butyl acrylate, May;

(0.97%) acrylonitrile, 3 ma.ch.

(2.9%) 1-methacrylate-1-tert-butyl peroxoethane and run for 1 hour. Then load 81 wt. H.

(78.6%) of butyl acrylate, 9 m.ch.

(8.7%) of acrylonitrile and continue eopolymerization for another 1.5 hours. The copolymer yield is 98.8%. The average diameter of latex particles 0, llli 0.04 microns. Latex does not coagulate with the introduction of 20 HcMa per 100 g of copolymer. Latex is incubated without forming a coagulum for 5 freezing cycles to -45 ° C by eating - thawing.

methyl diethylammonium benzene sulfonate structural formula

$ about;

live for 5 cycles without freezing, freezing to -70 ° C by evaporation.

Example 5. The process is carried out using the rio technology described in example 1. The reactor is loaded with 150 mash. (143%) of water, 3.6 mph. (3.4%) 2,4-dinonylphenyldecacio, ethyleneoxymethylmethylethylammonium benzoyl sulfonate of the structural formula

)

Na, Sp per 100 mah. copolymer. Latex maintains 5 freezing cycles to -70 ° C, followed by thawing without formation of a coagulum.

Example 6. The process is carried out according to the technology described in Example 1. 150 wt.h. (145%). Water, 6 May. including (5.8%) 2,4-dinonylphenyl decaoxyethylene oxymethylmethylammonium benzene sulfonate of the structural formula

100 ma.ch. polymer The latex is kept for 5 freezing cycles down to -70 ° C with thawing without forming a coagulum.

Example 7. The process is carried out according to the technology described in Example 1. 150 mas is charged into the reactor. (146%) of water, 6 ma.ch. (5.8%) 2,4-dinonyldecaoxyethylene-oxymethylmethyl-diethylme As seen from the above examples, the latecae, the polioe 4ee according to the proposed procedure, are highly resistant to electrolytes and low temperatures.

Samples of latexes were tested for resistance to long-term storage by keeping them at room temperature for 18 months. no delamination occurred. The latexes obtained by the proposed method can be stored and transported in any climatic conditions and, due to their high resistance to

Claims (3)

the action of electrolytes, latexes can Lateck not coagulable-45 mono-benzoyl sulfonate structural form40 wt.h. on the mules. gS211OOSNg-CH3 {CgY5) 2 y5 y5 oz is used to obtain various paint and varnish compositions. The method of obtaining stable polymer latexes by emulsion copolymerization of vinyl monomers with a non-bonded compound in the presence of a cationic surfactant of a quaternary ammonium salt - and a peroxide initiator, characterized in that, in order to simplify the technology, as well as to increase the stability of the latexes to electrolytes and low temperatures , as the quaternary ammonium salt, alkyl- or dialkylarylpolyoxyethyleneoxymethylmethylammonium benzene sulfonate of total ph is used. formulas: Vf оСН4СНг) й oCHj-iJ (CzHsJa H, de R is al; g "LCH 1Ii51 518 57) dialkylaryl-inNc-xOy. n 2-20; in the amount of 3.4-6.0% by weight of monomers, and as an unsaturated compound and simultaneously a peroxide initiator -1- (a-alkyl acrylate) g -1-tert-butylperoxyethane in an amount of 0.5-4.8% by weight monomers. Sources of information taken into account in the examination 1. GDR patent number 197140, cl. C 08 F 236/00, published 1974. 2.Patent of England No. 1438449, c. 3 P, published. 1975. 3. The patent of Germany 2602353, cl. C 08 F 36/18, published 1976 (prototype).