CN1493601A - A water-emulsion type fluorine-containing water and oil repellent agent and preparation method thereof - Google Patents

Abstract

The invention discloses a water-emulsion type fluorine-containing water and oil repellent agent and a preparation method thereof. The water-emulsion type fluorine-containing water and oil repellent agent of the present invention is an emulsion of a fluorine-containing copolymer in an aqueous medium obtained by pre-emulsifying monomers, emulsifiers and water through ultrasonic technology, and then initiating polymerization under an initiator. Compared with the previous technology, the water-emulsion type fluorine-containing water and oil repellent agent of the present invention has excellent water and oil repellency performance, and does not contain organic solvents that are harmful to the environment, and does not use more expensive initiators at the same time, 2'-Azobis(2-amidinopropane) dihydrochloride or 2,2'-azobis(isobutylamidine) dihydrochloride, the polymerization temperature is low, the polymerization speed is fast, and will have a very wide range of application prospects.

Description

A water-emulsion type fluorine-containing water and oil repellent agent and preparation method thereof

technical field

The invention relates to an organic solvent-free water-emulsion type fluorine-containing water and oil repellent agent and a preparation method thereof.

Background technique

Fluorine-containing polymers have many excellent properties, such as excellent water and oil resistance, aging resistance, high temperature resistance, extremely low surface tension and chemical stability, etc. It is well known that the copolymer of perfluoroalkylethyl (meth)acrylate is used in the design of hydrophobic and oil-repellent finishing agents of fabrics. From the consideration of environment and safety, such finishing agents have been dissolved in organic Developed from solvents to current water-based dispersions.

Since the (meth)acrylates containing perfluoroalkyl (abbreviated as Rf) groups are insoluble in water, and in order to obtain good water and oil repellency, a higher fluorine content is often required in the copolymer, therefore, Its good dispersion in water medium has always been a technical difficulty. In order to solve this problem, the method of adding a large amount of other additives is generally adopted. This type of additive is an organic solvent with high solubility in water and in fluorine monomers. Diffusion into polymer latex particles, such as U.S. Patent US08/048,350, acetone is added as a co-solvent for polymerization during polymerization, and Japanese Patent JP309562/1999 proposes to use a water-soluble high-viscosity solvent (viscosity above 3cP at 25°C) such as triethyl Glycol, dipropylene glycol dimethyl ether, etc. are added to water to form a composite water system medium. However, the use of a solvent may cause a decrease in the ignition point of the aqueous dispersion or remain in the treated object, which is very disadvantageous. No matter what kind of solvent is used, it will increase the VOC value (volatile organic compound) of the system, which is not good for the environment. In order to solve the problem of stable dispersion and polymerization of fluoromonomers, a relatively large amount of fluorosurfactant can also be used as an emulsifier, but this will increase the cost of the emulsion.

The introduction of ultrasonic technology into emulsion polymerization has recently attracted attention. For example, Wang Qi et al. used ultrasonic radiation to study the microemulsion polymerization of methyl methacrylate (Chemical Journal of Chinese Universities, 1237-1240: 2001). However, the application of ultrasonic technology to the preparation of water and oil repellent emulsions with high fluorine content has not been reported.

Fluorine-containing emulsion polymerization initiators generally use 2,2'-azobis(2-amidinopropane) dihydrochloride or 2,2'-azobis(isobutylamidine) dihydrochloride, such initiators It is water soluble and can be induced at low temperature, but it is expensive and easy to decompose, requiring low temperature storage.

Contents of the invention

The technical problem to be solved in the present invention is to disclose a water-emulsion type fluorine-containing water and oil repellent agent and its preparation method. deficiencies to meet the needs of the relevant departments.

The water-emulsion type fluorine-containing water and oil repellent agent of the present invention is an emulsion of a fluorine-containing copolymer in an aqueous medium obtained by pre-emulsifying monomers, emulsifiers and water through ultrasonic technology, and then initiating polymerization under an initiator. Preferred weight percentages include:

Fluorinated copolymer 5～40%

Emulsifier 0.5～4%

Water balance

Said monomer is the mixture of monomer A1 and monomer A2, wherein:

The percentage of monomer A1 in the total weight of the copolymer is 35% to 90%. If it is lower than 35%, then the water resistance, oil repellency and antifouling ability are not enough; at the same time, it should be less than 90%. If it is too high, it will play a role in solubilization The A2 monomer will be too little, resulting in a decrease in dispersing ability. The content of 50% to 80% is more appropriate, so that the dispersion stability and water and oil resistance performance can reach a good balance;

The percentage of monomer A2 in the total weight of the copolymer is 10%-65%.

The monomer A1 mentioned is a perfluoroalkylethyl (meth)acrylate with Rf group;

The perfluoroalkylethyl (meth)acrylate with the Rf group refers to the compound in which the perfluoroalkyl is located at the alcohol residue of (meth)acrylate, and its structure is shown in the following formula:

in:

The Rf group is preferably that all hydrogen atoms are replaced by fluorine atoms, and the structure of the terminal part is preferably -CF ₂ CF ₃ ; the Rf group can be a straight chain structure or a branched chain structure, and the straight chain structure is preferable; the Rf group The number of carbon atoms in is preferably 2 to 20, more preferably 6 to 16;

R is H or _CH3 ;

A is O, S or NR;

R ₁ is an alkylene group containing 1 to 15 carbon atoms;

More specific examples can be given:

CH ₂ ＝CHCOOCH ₂ CH ₂ (CF ₂ ) ₃ CF ₃

CH ₂ ＝CHCOOCH ₂ CH ₂ (CF ₂ ) ₅ CF ₃

CH ₂ ＝CHCOOCH ₂ CH ₂ (CF ₂ ) ₇ CF ₃

CH ₂ ＝CHCOOCH ₂ CH ₂ (CF ₂ ) ₉ CF ₃

CH ₂ ＝CHCOOCH ₂ CH ₂ (CF ₂ ) ₁₁ CF ₃

CH ₂ ＝CHCOOCH ₂ CH ₂ (CF ₂ ) ₁₃ CF ₃

CH ₂ ＝CHCOOCH ₂ CH ₂ (CF ₂ ) ₁₅ CF ₃

CH ₂ ＝CHCOOCH ₂ CH ₂ (CF ₂ ) ₁₇ CF ₃

CH ₂ ＝C(CH ₃ )COOCH ₂ CH ₂ (CF ₂ ) ₃ CF ₃

CH ₂ ＝C(CH ₃ )COOCH ₂ CH ₂ (CF ₂ ) ₅ CF ₃

CH ₂ ＝C(CH ₃ )COOCH ₂ CH ₂ (CF ₂ ) ₇ CF ₃

CH ₂ ＝C(CH ₃ )COOCH ₂ CH ₂ (CF ₂ ) ₉ CF ₃

CH ₂ ＝C(CH ₃ )COOCH ₂ CH ₂ (CF ₂ ) ₁₁ CF ₃

CH ₂ ＝C(CH ₃ )COOCH ₂ CH ₂ (CF ₂ ) ₁₃ CF ₃

CH ₂ ＝C(CH ₃ )COOCH ₂ CH ₂ (CF ₂ ) ₁₅ CF ₃

CH ₂ ＝CHCOOCH ₂ CH ₂ NSO ₂ (CF ₂ ) ₅ CF ₃

CH ₂ ＝CHCOOCH ₂ CH ₂ (CF ₂ ) ₅ CF ₃

For reasons of economy and practicality, monomer A1 is preferably a mixture of two or more monomers with different Rf group structures as mentioned above.

According to the present invention, monomer A2 is a kind of and its mixture in other vinyl monomers except A1, and monomer A2 can reduce cost, and provide the adhesion, hardness, film-forming property, cross-linking property of special liner and adhesion etc., preferred monomer A2 includes styrene, ethylene, propylene, methyl (meth)acrylate, butyl (meth)acrylate, (meth)acrylic acid, ethyl (meth)acrylate, acrylic acid Laurate, vinyl chloride, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, vinylpyrrolidone, styrene, divinylbenzene, acrylamide, N-methylolacrylamide, vinyl acetate One of ester, vinyl propionate, (meth)acrylonitrile or glycidyl (meth)acrylate, etc.;

The emulsifier mentioned includes one of anionic, cationic or nonionic;

The mentioned anionic surfactants include carboxylates of C ₇ to C ₂₁ ; alkyl sulfates of C ₈ to C ₁₈ , such as sodium dodecyl sulfate; fatty sulfonates such as dodecyl sulfonate sodium acid, etc.; fatty benzene sulfonates, such as sodium dodecylbenzene sulfonate, etc.; phosphate esters, such as ^Rhodafac® RE-610 from Rhodia Corporation.

The cationic type mentioned includes C ₁₂ -C ₁₈ alkyl quaternary ammonium salt, ether structure quaternary ammonium salt, alkyl biguanide hydrochloride, etc.;

The nonionics mentioned include polyoxyethylene carboxylate, polyol acid ester, polyoxyethylene alkyl ether, polyoxyethylene alkaryl ether, polyoxyethylene amide, and the like.

The emulsifier can be one or more combinations of the above, and is preferably used in combination of ionic and nonionic.

The preparation method of the water-emulsion type fluorine-containing water and oil repellent agent of the present invention comprises the following steps:

(1) Put the monomer mixture, water, and emulsifier into the container, put it into an ultrasonic cleaning machine and perform ultrasonication for a certain period of time to obtain a stable pre-emulsion. This technology is well known and feasible, and relevant professionals can easily implement it.

(2) Add an initiator, preferably a water-soluble peroxide, such as hydrogen peroxide-ferrous chloride, ammonium persulfate-sodium bisulfite, potassium persulfate-ferrous chloride, potassium persulfate-primary ten Two carbon mercaptans, etc., can also add a catalytic amount of water-soluble copper salt such as copper sulfate as a catalyst in the system;

The amount of the initiator is 0.1-3% of the weight of the monomer;

The polymerization reaction temperature can be changed within a wide range, namely 30°C to 120°C. Preferably at 40-60°C;

In order to control the molecular weight, a chain transfer agent such as dodecyl mercaptan, carbon tetrachloride or carbon tetrabromide may be added to the reaction system, and the amount of the chain transfer agent is 0.05-1% by weight of the monomer.

The articles suitable for using the water-emulsion type water and oil repellent agent of the present invention to process can be various fiber products, such as natural animal and plant fibers such as cotton, hemp, wool, polyamide, polypropylene, polyacrylonitrile, polyester or chemical synthetic fibers. The aqueous dispersion of the present invention can be made to adhere to the surface of the object to be treated by soaking and coating, and then be treated by drying. The water and oil repellent prepared by the present invention can also be used for the coating of some hard surfaces such as antifouling coatings for interior and exterior walls, ship coatings, tiles, bricks, cement, concrete, etc.

Compared with the previous technology, the water-emulsion type fluorine-containing water and oil repellent of the present invention has excellent water and oil repellency, and does not contain organic solvents that are harmful to the environment, and does not use more expensive initiators2,2 '-Azobis(2-amidinopropane) dihydrochloride or 2,2'-azobis(isobutyramide) dihydrochloride, the polymerization temperature is low, the polymerization speed is fast, and will have a very wide range of Application prospect.

Detailed ways

Hereinafter, the present invention will be explained more specifically based on examples, but the present invention is not limited by these examples.

Example 1

Mix the following ingredients in a 200 ml beaker: 30 g perfluoroalkylethyl methacrylate, 10 g laurate acrylate, 8 g butyl methacrylate, 1 g N-methylolacrylamide, 1 g hydroxypropyl methacrylate, Dodecyl mercaptan 0.25g, sodium lauryl sulfate 1.5g, alkylphenol polyoxyethylene ether-10 0.5g, deionized water 170g, placed in SK1200H type ultrasonic cleaner for pre-emulsification for 1 hour, obtained stable water dispersion. Add the pre-emulsion to a glass reactor equipped with a stirrer, a thermometer and a condenser, then add 0.3 g of sodium bicarbonate, 0.3 g of potassium persulfate, 0.15 g of sodium bisulfite, and 0.025 g of copper sulfate, and pass through nitrogen to remove oxygen. Stir and heat, and the temperature of the water bath is raised to 50°C. After 3 minutes, opalescence appears, and the reaction is continued for 5 hours to obtain about 223 g of latex with a solid content of 23.5%.

Example 2

Mix the following ingredients: 35 g perfluoroalkylethyl acrylate, 13 g stearyl acrylate, 1 g N-methylolacrylamide, 1 g hydroxyethyl acrylate, 0.25 g dodecyl mercaptan, 0.25 g octadecyltrimethyl 1.5 g of ammonium chloride and 160 g of deionized water were placed in a USC-102 ultrasonic cleaner for pre-emulsification for 0.5 hours to obtain a stable aqueous dispersion. Add the pre-emulsion into a glass reactor equipped with a stirrer, a thermometer and a condenser, then add 0.3 g of sodium bicarbonate, 0.3 g of ammonium persulfate, and 0.15 g of sodium bisulfite, pass nitrogen to deoxygenate, stir and heat to a water bath at 45 ℃ for 5 hours to obtain about 183 g of latex with a solid content of 28.6%.

Example 3-8

Prepare fluorine-containing emulsion substantially according to the method for embodiment 1 or 2, and its monomer composition formula is listed in table 1:

The monomer consumption (parts by weight) in Table 1 Embodiment 3-8

Monomer 3 4 5 6 7 8

Perfluoroalkylethyl acrylate 70 80 50 - - - -

Perfluoroalkylethyl methacrylate - - - - 60 70 60

Laurate Acrylate 20 - 30 25 - 30

Acrylic Stearate 20 - 30 -

Vinylidene chloride 10 0 20 15 0 10

2-Hydroxyethyl Acrylate - 2 - 2

3-Hydroxypropyl methacrylate 2 - - - 2 - -

N-Hydroxyacrylamide 2 2 2 2 2 2 2

Example 9

Test Methods:

The water resistance test can be carried out by the following methods:

A series of standard test solutions (listed in Table 2) prepared from water and isopropanol (IPA) were dropped onto the sample. Starting with the low number (water resistance test number 1), place one drop (approximately 5mm in diameter or 0.05ml in volume) in three locations at least 2 inches apart. Observe these droplets for 10 seconds. If, after 10 seconds, two of the three drops still appear to be spherical to hemispherical, add 3 drops of the next higher number to adjacent locations and observe for 10 seconds. Continue until 2 out of 3 droplets of a test solution fail to remain spherical to hemispherical. The water resistance of the sample is the highest mark where 2 of the 3 droplets maintain a spherical to hemispherical shape.

              Table 2 Standard water test solution

Water resistance test label Composition %IPA % water Water resistance test label Composition % IPA % water

1 2 98 7 50 50

2 5 95 8 60 40

3 10 90 9 70 30

4 20 80 10 80 20

5 30 70 11 90 10

6 40 60 12 100 0

Oil resistance is carried out using the following methods:

For the polymer sample, the oil resistance test was carried out according to the revised AATCC standard test method No. 118, and the method was as follows: a series of organic liquids (listed in Table 3) were dropped on the polymer sample. At the beginning, drop 1 drop (approximately 5mm in diameter or 0.05ml in volume) of the test solution of the lowest mark (oil resistance test mark 1) on each of the three positions of at least 5mm. Observe these droplets for 30 seconds. If, after this time, 2 of the 3 droplets are still spherical or hemispherical and there is no wicking around the droplet, add 3 more drops of the next higher number in an adjacent position and observe for 30 seconds at the same time bell. Until two of the three droplets of a test solution fail to maintain a spherical to hemispherical shape or appear infiltration, the oil resistance of the polymer sample is that two of the three droplets remain spherical to hemispherical within 30 seconds The test solution with the highest label and no infiltration phenomenon.

         Table 3 Oil resistance test

Oil resistance test label Test solution

1 Nojol ^* Purified Mineral Oil ( ^* plough company trade name)

2 65/35 Nojol/n-Hexadecane

3 n-hexadecane

4 n-tetradecane

5 n-dodecane

6 n-heptane

Using the above method, the polymer emulsion is coated on a 18mm×18mm quartz plate to form a uniform film, and heat-treated at 130°C for 3-5 minutes to measure the water and oil repellency of the polymer sample.

The water and oil repellency of table 4 embodiment sample

Stock Solution Water Resistant Oil Resistant

Example 1 12 5

Example 2 12 6

Example 3 12 6

Example 4 12 6

Example 5 12 5

Example 6 12 6

Example 7 12 6

Example 8 12 6

It can be seen from the above tests that the water-emulsion type fluorine-containing water and oil repellent agent of the present invention has a water repellency of 12# and an oil repellency of 5-6#, and the emulsion shows good water and oil repellency.

Claims (10)

1. A water-emulsion type fluorine-containing water- and oil-repellent agent, characterized in that it is an emulsion in an aqueous medium of a fluorine-containing copolymer obtained by polymerization after pre-emulsification of monomers, emulsifiers and water; Said monomer is the mixture of monomer A1 and monomer A2, wherein: The percentage of monomer A1 accounting for the total weight of the copolymer is 35% to 90%, and the percentage of monomer A2 accounting for the total weight of the copolymer is 10% to 65%; The monomer A1 mentioned is a perfluoroalkyl ethyl (meth)acrylate with a perfluoroalkyl group (abbreviated as Rf), and its structure is shown in the following formula:

R is H or _CH3 ; A is O, S or NR; R ₁ is an alkylene group containing 1 to 15 carbon atoms; Monomer A2 is a kind of and mixture thereof in other vinyl monomers except monomer A1; The mentioned emulsifier is one of anionic, cationic or nonionic and a mixture thereof. 2. The water-emulsion type fluorine-containing water and oil repellent agent according to claim 1, characterized in that Rf is all hydrogen atoms replaced by fluorine atoms, and the structure of the terminal part is -CF ₂ CF ₃ . 3. The water-emulsion type fluorine-containing water and oil repellent according to claim 2, wherein Rf is a linear structure or a branched structure. 4. The water-emulsion type fluorine-containing water and oil repellent agent according to claim 3, characterized in that Rf has 2 to 20 carbon atoms. 5. The monomer A1 is a mixture of one or more of the following monomers: CH ₂ ＝CHCOOCH ₂ CH ₂ (CF ₂ ) ₅ CF ₃ CH ₂ ＝CHCOOCH ₂ CH ₂ (CF ₂ ) ₇ CF ₃ CH ₂ ＝CHCOOCH ₂ CH ₂ (CF ₂ ) ₉ CF ₃ CH ₂ ＝CHCOOCH ₂ CH ₂ (CF ₂ ) ₁₁ CF ₃ CH ₂ ＝CHCOOCH ₂ CH ₂ (CF ₂ ) ₁₃ CF ₃ CH ₂ ＝CHCOOCH ₂ CH ₂ (CF ₂ ) ₁₅ CF ₃ CH ₂ ＝CHCOOCH ₂ CH ₂ (CF ₂ ) ₁₇ CF ₃ CH ₂ ＝C(CH ₃ )COOCH ₂ CH ₂ (CF ₂ ) ₃ CF ₃ CH ₂ ＝C(CH ₃ )COOCH ₂ CH ₂ (CF ₂ ) ₅ CF ₃ CH ₂ ＝C(CH ₃ )COOCH ₂ CH ₂ (CF ₂ ) ₇ CF ₃ CH ₂ ＝C(CH ₃ )COOCH ₂ CH ₂ (CF ₂ ) ₉ CF ₃ CH ₂ ＝C(CH ₃ )COOCH ₂ CH ₂ (CF ₂ ) ₁₁ CF ₃ CH ₂ ＝C(CH ₃ )COOCH ₂ CH ₂ (CF ₂ ) ₁₃ CF ₃ CH ₂ =C(CH ₃ )COOCH ₂ CH ₂ (CF ₂ ) ₁₅ CF ₃ . 6. The water-emulsion type fluorine-containing water and oil repellent according to claim 1, wherein the monomer A2 comprises styrene, ethylene, propylene, methyl (meth)acrylate, butyl (meth)acrylate , (meth)acrylic acid, ethyl (meth)acrylate, laurate acrylate, vinyl chloride, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, vinylpyrrolidone, styrene, divinyl One of phenylbenzene, acrylamide, N-methylolacrylamide, vinyl acetate, vinyl propionate, (meth)acrylonitrile or glycidyl (meth)acrylate, and a mixture thereof. 7. The water-emulsion type fluorine-containing water and oil repellent according to any one of claims 1 to 6, characterized in that the weight percentage content is: Fluorinated copolymer 5～40% Emulsifier 0.5～4% Water balance. 8. The preparation method of the water-emulsion type fluorine-containing water and oil repellent according to any one of claims 1 to 7, characterized in that it comprises the following steps: (1) The monomer mixture, water and emulsifier are ultrasonically emulsified; (2) Add an initiator and polymerize under the condition of 30°C to 120°C. 9. The preparation method of the water-emulsion type fluorine-containing water and oil repellent according to claim 8, wherein the initiator comprises hydrogen peroxide-ferrous chloride, ammonium persulfate-sodium bisulfite, persulfuric acid Potassium-ferrous chloride or potassium persulfate-primary dodecyl mercaptan and a mixture thereof, the amount of the initiator is 0.1-3% by weight of the monomer. 10. The preparation method of the water-emulsion type fluorine-containing water and oil repellent according to claim 8, wherein a chain transfer agent is added during the polymerization reaction, and the transfer agent described includes lauryl mercaptan, tetramercaptan Carbon chloride or carbon tetrabromide, the amount of the chain transfer agent is 0.05-1% of the weight of the monomer.