JPS647634B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a water and oil repellent emulsion. More specifically, the present invention relates to a method for producing a water and oil repellent emulsion that does not contain an emulsifier. Generally, water and oil repellent emulsions are manufactured using emulsifiers. Nonionic emulsifiers are used mainly for the following reasons. In other words, anionic and cationic emulsifiers tend to destabilize latex depending on the type of comonomer constituting the water/oil repellent copolymer, and in particular, cationic emulsifiers tend to destabilize the latex. Copolymers containing vinyl halides, vinylidene halides, etc. as comonomer components, which give good performance results, only give emulsions with poor stability. Furthermore, the presence of anionic emulsifiers significantly impairs water and oil repellency. Furthermore, these emulsifiers
Since it itself is ionic, it is not possible to freely adjust the composition with various fiber treatment agents. On the other hand, nonionic emulsifiers, such as polyethylene glycol alkyl phenol ether and polyethylene glycol alkyl ether, which are commonly used because of their excellent dispersibility, have poor biodegradability and are therefore Not only does it cause problems in wastewater treatment,
When vinyl halide, vinylidene halide, or the like is selected as a comonomer for a water- and oil-repellent copolymer, this biodegradation is promoted, and this is the cause of discoloration and discoloration of textiles. In order to avoid deterioration in performance of the water and oil repellent emulsion due to the presence of such an emulsifier, a polymerizable compound containing a perfluoroalkyl group having 8 or more carbon atoms and a polymerizable compound containing a hydrophilic group having 9 or more oxyalkylene units are included as structural units. An aqueous dispersion in which a copolymer is dispersed in an aqueous medium substantially without the use of an emulsifier has been proposed, and it has been reported in JP-A No. It is described in Publication No. 53-134786. However, this water and oil repellent agent shows a particular drop in water repellency, and even when a copolymer containing 60% by weight of a perfluoroalkyl group-containing polymerizable compound is used, its water repellency is 70%, which is good. At most
It is 80. As a result of various studies in search of a water and oil repellent emulsion that does not contain an emulsifier and has excellent water and oil repellency, the present inventors found that a vinyl monomer containing a fluoroalkyl group having 3 or more carbon atoms, Other vinyl monomers and crosslinking monomers that do not contain hydrophilic groups that can be copolymerized with this monomer are mixed with monohydric lower alcohols, cyclic ethers, or hydrophilic monomers that are aprotic polar solvents in the absence of emulsifiers. It has been discovered that a water and oil repellent emulsion that solves the above problems can be produced by random copolymerization in an aqueous organic solvent solution. Therefore, the present invention relates to a method for producing a water and oil repellent agent carried out in this manner. Examples of the vinyl monomer containing a fluoroalkyl group having 3 or more carbon atoms include the following compounds. However, in the formula, R is a divalent organic group, R' is a hydrogen atom or a methyl group,
R″ is a lower alkyl group, and n is 3 or more,
Generally it is an integer between 3 and 20. CH ₂ ＝CR′COORC _o F _2o+1 CH ₂ ＝CR′COOCH ₂ CH ₂ C ₆ F ₁₃ CH ₂ ＝CR′COOCH ₂ CH ₂ C ₈ F ₁₇ CH ₂ ＝CR′COOCH ₂ CH ₂ C ₁₀ F ₂₁ CH ₂ =CR′COOCH ₂ CH ₂ C ₁₂ F ₂₅ Other vinyl monomers that do not contain a hydrophilic group that can be copolymerized with this include, for example, vinyl halides, vinylidene halides, alkyl, aralkyl, aryl, allyl esters of acrylic acid or methacrylic acid, maleic acid, or fumaric acid. Alkyl acids, aralkyl esters, alkyl vinyl ethers, benzoic acid vinyl esters, substituted or unsubstituted styrenes, diene compounds, etc. are used. These other vinyl monomers are used to increase the amount of expensive fluorine-containing vinyl monomers, but they must not impair water and oil repellency, especially oil repellency, so they are commonly used. It is used in a copolymerization proportion of about 90% by weight or less, preferably about 80% by weight or less in the polymer. The copolymer contains crosslinkable monomers, such as N-methylol (meth)acrylamide and N-butoxymethylol ( meth)acrylamide, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, diacetone acrylamide, glycidyl (meth)acrylate, allyl glycidyl ether, etc., preferably in an amount of about 0.01 to 20% by weight in the copolymer. is copolymerized in an amount of about 0.5 to 10% by weight. In the random copolymerization reaction, a fluorine-containing vinyl monomer (about 10 to 100 parts by weight, preferably about 20 to 80 parts by weight)
Other vinyl monomers (approximately 90 to 0 parts by weight, preferably approximately 80 to 20 parts by weight) as well as crosslinking monomers, hydrophilic organic solvents (approximately 10 to 10,000 parts by weight) and water (approximately 90 to 0 parts by weight)
~20,000 parts by weight) were thoroughly stirred and mixed using a colloid mill, high-speed homogenizer, etc., and the mixture was thoroughly replaced with nitrogen under reflux conditions, followed by azobisisobutyramidine hydrochloride, potassium persulfate, sodium persulfate, ammonium persulfate, A polymerization initiator such as hydrogen peroxide is added, and reflux is continued until the polymerizable monomer GLC (gas chromatography) disappears, and that point is defined as the end point of the reaction. The polymerization method is
The method is not limited to these methods, and ordinary emulsion polymerization methods can be used as they are. During this random copolymerization reaction, no emulsifier is used, and an aqueous solution of a specific hydrophilic organic solvent is used as the reaction medium. As a hydrophilic organic solvent,
Monohydric lower alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, and isobutanol; cyclic ethers such as dioxane and tetrahydrofuran; or aprotic substances such as acetonitrile, dimethylformamide, dimethylacetamide, dimethylsulfoxide, and sulfolane. The polar solvent is approximately 5 to 40
%, preferably about 5-20%. These hydrophilic organic solvents are naturally miscible with water, but they also have a radical chain transfer coefficient.
0.1×10 ^-4 or more, preferably 0.2×10 ⁴ or more (60℃)
It is desirable that In other words, hydrophilic organic solvent compounds are thought to contribute to stabilizing the emulsion by being incorporated into the polymer chain through chain transfer, and in the case of solvent compounds that are difficult to chain transfer, hydrophilic organic solvent compounds It is sufficient that the hydrophilic effect is large, or even a solvent compound with a small hydrophilic effect is preferably used as long as it is easy to chain transfer. From this point of view, preferred hydrophilic organic solvents include methanol, isopropanol, and acetonitrile. The water- and oil-repellent emulsion of the present invention produced in this manner is similar to the water- and oil-repellent emulsion of the above-mentioned patent publication in that no emulsifier is present, but in the latter, the oxyalkylene unit is 9 The emulsion is stabilized by copolymerizing a hydrophilic group-containing polymerizable compound having 1 or more hydrophilic groups, and the method of ordinary soap-free emulsion polymerization is applied to the production of water and oil repellent copolymers. Although this stabilizes the emulsion, it causes a decline in the essential water and oil repellency performance, especially the water repellency performance. Therefore, even if a copolymer with a relatively low copolymerization ratio of fluorine-containing vinyl monomer is used, a stable emulsion can be formed without almost impairing the water and oil repellency properties originally required of the copolymer. I'm letting you do it. Furthermore, as a matter of course, the emulsion according to the present invention does not use an emulsifier, so that no special treatment of waste liquid or the like is required. On the other hand, nonionic surfactants such as the nonyl phenyl ether/polyethylene glycol adduct described in Japanese Patent Publication No. 53-4159 are difficult to decompose by microorganisms, making it important to take measures against pollution. It's coming. In addition, the water and oil repellent emulsion of the present invention does not cause significant foaming unlike other water and oil repellents, making it extremely easy to use during water and oil repellent treatment at the end user stage. There is. The copolymer emulsion according to the present invention is prepared by diluting it with water or the like to adjust the solid content to a water and oil repellent concentration of about 0.1 to 1%, and then applying it by spraying, pad mangle method (immersion method), etc. It is used in the processing of raw fiber fabrics, and then dried (approximately 80%
~120°C) and curing (approximately 120-180°C). Next, the present invention will be explained with reference to examples. Example 1 Perfluorooctylethyl acrylate
50 parts by weight Vinylidene chloride 50 2-hydroxyethyl acrylate 5 N-methylolacrylamide 5 n-dodecyl mercaptan 0.4 Methanol 53.2 Water 422 The above component mixture was thoroughly mixed and stirred in a colloid mill, and then the inside of the reactor was sufficiently purged with nitrogen. Thereafter, 6.25 parts by weight of azobisisobutyramidine hydrochloride was added as a polymerization initiator, and a copolymerization reaction was carried out at 70 to 80°C for 8 hours. A milky-white to yellow emulsion was obtained, and the solid concentration only decreased from 18.8% to 18.3% by centrifugation at 3000 rpm for 10 minutes, and no increase in precipitation occurred even after leaving it at room temperature for 6 months. A stable emulsion state was formed. This emulsion is diluted with water to prepare a water and oil repellent with a solid content concentration of 0.5%, and cotton cloth (cloth), polyester cloth (cloth) or cotton (65)/polyester (35) blended fabric is added to this emulsion. (cloth) was soaked. For soaked cloth, at 80℃ for 15 minutes, then
A heat treatment was performed at 170° C. for 3 minutes, and a water and oil repellency test was conducted on the product. The test results obtained are shown in Table 1 below. Table 1 Water repellency Cloth 100 ^- Cloth 90 ⁺ Cloth 100 Oil repellency Cloth 130 Cloth 150 Cloth 130 [Water repellency test] A drop of water was dropped on the treated cloth, and the condition was observed after 5 minutes.

[Oil repellency test]

A drop of the test solution (mixed solution in a specific proportion as shown in the table below) is placed on the treated fabric and the condition is observed after 5 minutes have elapsed. If the dropped test solution is retained on the cloth, test with a test solution containing more n-heptane, and conversely, if it is not retained on the cloth, test with a test solution containing even more n-heptane. do. Then, using the test liquid that can be retained on the cloth at its limit, the oil repellency is evaluated based on the oil repellency evaluation shown in the table below. In the oil repellency evaluation, the case where 100% Nudyol is retained is 50, and the case where 100% Nudyol is not retained is 0.

[Table] Examples 2 to 3 In Example 1, instead of vinylidene chloride,
Equal amounts of the following vinyl comonomers were used: (Example 2) Benzyl methacrylate (Example 3) Stearyl methacrylate Example 4 In Example 2, 75 parts by weight of perfluorooctylethyl acrylate and 25 parts by weight of benzyl methacrylate were used, and 2-hydroxyethyl acrylate and N - 5 parts by weight of diacetone acrylamide were used instead of methylol acrylamide. Example 5 In Example 5, the amounts of perfluorooctylethyl acrylate and benzyl methacrylate were exchanged. Example 6 In Example 2, 1 part by weight each of 2-hydroxyethyl acrylate and N-methylolacrylamide was used. Example 7 In Example 6, the same amount of dioxane was used instead of methanol. Example 8 In Example 6, the same amount of vinylidene chloride was used instead of benzyl methacrylate, and the same amount of acetonitrile was used instead of methanol. Examples 9 to 11 In Example 1, the amount of vinylidene chloride used was
The amount was changed to 35 parts by weight, and 15 parts by weight of vinyl chloride was used instead. Furthermore, 5 parts by weight of diacetone acrylamide was used in place of 2-hydroxyethyl acrylate and N-methylol acrylamide, and the same amount of the following hydrophilic organic solvent was used in place of methanol. Example 9 Dimethylformamide (Example 10) Dimethyl sulfoxide (Example 11) Sulfolane Examples 12-13 In Example 1, methanol was replaced with the same amount of the following hydrophilic organic solvents. (Example 12) Isopropanol (Example 13) Isobutanol Comparative Examples 1-2 In Example 1, the amount of vinylidene chloride used was
35 parts by weight, 15 parts by weight of vinyl chloride was used instead, and the same amount of the following hydrophilic organic solvent was used instead of methanol. (Comparative example 1) Ethyl cellosolve (Comparative example 2) Propylene glycol For each emulsion obtained in Examples 2 to 13 and Comparative examples 1 to 2 above, Example 1
Similarly, the stability and water and oil repellency of the emulsion were evaluated. The test results obtained are shown in Table 2 below.

Table Comparative Example 3 In Example 1, the same amount of acetone was used instead of methanol. During the polymerization reaction, the resulting copolymer precipitated, making it impossible to form a stable emulsion.

Claims (1)

[Claims] 1 A vinyl monomer containing a fluoroalkyl group having 3 or more carbon atoms, another vinyl monomer that does not contain a hydrophilic group copolymerizable with this, and a crosslinkable monomer in the absence of an emulsifier, A method for producing a water and oil repellent emulsion, which comprises random copolymerization in an aqueous solution of a hydrophilic organic solvent such as a monovalent lower alcohol, a cyclic ether, or an aprotic polar solvent.