KR0126891B1 - Method for modifying surface of hydrophobic polymer - Google Patents

Abstract

treating a hydrophobic polymer material by chemical, physical or optical means to form radicals on the surface of the hydrophobic polymer; coating the radical-formed surface of the hydrophobic polymer with an aqueous solution containing a hydrophilic substance having double bonds for forming radicals, a surfactant, an oxidant and a radical polymerization initiator; and graft copolymerizing the hydrophilic substance having double bonds with the surface of the hydrophobic polymer.

Description

Surface modification method of hydrophobic polymer

The present invention relates to a hydrophilic surface modification method of a hydrophobic polymer, and specifically, the surface of a hydrophobic polymer is activated by chemical, physical or optical means, and the copolymer is prepared by coating an aqueous solution in which a water-soluble monomer, an initiator, and a crosslinking agent are mixed. It is a hydrophilic surface modification method of hydrophobic polymer consisting of.

Surface modification methods for hydrophilizing hydrophobic polymers have been studied. As a method of manufacturing an invincible film, Japanese Patent No. 57-71,770 discloses a method of hydrophilizing by applying polyvinyl alcohol, but has a disadvantage in that the water resistance, durability is weak and the processing method is complicated. In addition, Japanese Patent No. 57-187,347 discloses a method of spraying a surfactant on the surface of a hydrophobic film, but when the method is used, the initial effect is excellent as water droplets and dripping of the attached part are easily lost and the surfactant is easily lost. One is very short in durability. In addition, Japanese Patent Nos. 50-153,072 and 52-105,936 disclose a method of hydrophilizing a hydrophilic film by coating a hydrophilic resin with hydroxyethyl methacrylate and N-Vinylpyrolidon. A method of thermosetting a hydrophilic polymer of acrylic acid with a crosslinking agent such as melamine, epoxy, and the like is disclosed.

However, the surface-modified polymer by the above method has a disadvantage that the surface is hard and is separated by heat shrinkage and expansion, and is broken. Other existing inventions of the surface modification method by the above surface coating method include German Patent Publication No. 3,324,390, Japanese Patent Publication No. 58-76,030, 58-103,533, 58-89,360, 59-227,239 59-80,468, 58-90,960, 57-162,736, 60-137,639, 57-187,347, 58-13,685, 4,338,420, 4,341,825, 3,386,855, And European Patent Publication No. 142,773.

In addition, hydrophobic polymer modification methods are known in which hydrophilization is hydrophilized not only on the surface but also on the inside by mixing and processing a hydrophobic polymer with a surfactant such as stearic acid, lauryl acid, and the like.

Examples of such methods include Japanese Patent Publication Nos. 38-4171, 38-03572, 38-21112, 52-69950, 45-4617, 45-13705, 49-29294 45-36014, 54-55048, 54-74847, and the like.

However, the modified hydrophobic polymer produced by the above method causes a change in the mechanical and chemical properties of the hydrophobic polymer, and the surface hydrophilicity does not last long as the small molecule surfactant flows out over time. Will be.

The inventors of the present invention have already applied for the crosslinking polymerization of the hydrophobic polymer film by dissolving a hydrophilic monomer and a crosslinking agent in a solvent and irradiating with ultraviolet light to impart invincibility to the polymer film. (Korean Patent No. 04529 and 047832).

However, the present inventors know that there is a problem of environmental pollution, fire risk, price increase due to the organic solvent by using the organic solvent in the method of the inventors described above, and proceed to research to further improve the water The use of the solvent as a solvent overcomes the above-mentioned disadvantages and invents a new compounding condition in which the mechanism of the copolymerization reaction by the crosslinking agent and the initiator is different. In addition, in the polymerization method, the invention is a method that can expect the reduction of equipment and electric charges by performing room temperature polymerization (5-50 ° C.) rather than a photopolymerization method.

That is, the present invention is to treat the hydrophobic polymer material by chemical, physical or optical means to generate a radical on the surface of the hydrophobic polymer, a hydrophilic material having a double bond capable of forming a radical and a hydrophilic functional group in the terminal group, An aqueous solution containing a surfactant, an oxidizing agent and a ladil polymerization initiator is applied to the surface of the radical-forming hydrophobic polymer so that a hydrophilic material having a double bond capable of forming radicals and a hydrophilic functional group at the terminal is graft copolymerized with the surface of the hydrophobic polymer. A hydrophilic surface modification method of hydrophobic polymer is provided.

Detailed description of the present invention, hydrophobic polymer materials include all types of hydrophobic polymer materials having thermoplastic or thermosetting properties such as, for example, polyethylene, polymethylmethacrylate, polycarbonate, polyethylene terephthalate and the like.

Hydrophobic polymer materials produce chemically active radicals by treating hydrophobic polymer surfaces by chemical, physical and optical means.

The method of generating radicals is a well-known method. An example of a chemical method is 10 to 80% of chromium oxide (V / V) and 10 to 80% of concentrated sulfuric acid (V / V). The mixed solution at the ratio of V) is immersed and oxidized. The sulfonation proceeds to the surface, so that the surface becomes negatively charged, thereby facilitating the hydrophilization reaction. In the case of peroxide treatment, there are methods in which 30-90% (V / V) of perchloric acid is surface-treated with a saturated solution of 10-70% (V / V) of potassium perchlorate.

The physical pretreatment method involves rubbing the surface with sandpaper or fine grinding machine to induce the reaction by instant hydrophilization treatment at the place where the polymer chain is separated, or by optical or plasma or corona discharge treatment. There is a method in which high frequency discharge generated by generating high frequency is discharged from an electrode to activate a surrounding gas layer to generate activated radicals. The hydrophilic monomer aqueous solution of the present invention is applied onto the activated surface as described above. At this time, the surface of the polymer should be uniformly applied, but when the aqueous solution is used, hydrophobicity does not wet the surface, surface tension occurs, and water droplets occur. Thus, a method of making the coating uniform using an organic solvent without using water was performed (see Korean Patent Nos. 046529 and 047832).

However, organic solvents are expensive and cause serious problems in environmental pollution and have a high risk of fire during the reaction process.

In the present invention, such problems caused when using water can be overcome by introducing a hydrophilic monomer aqueous solution according to the present invention containing a surfactant.

The hydrophilic aqueous solution used in the hydrophilic surface modification method of the hydrophobic polymer material according to the present invention essentially includes the following components.

1. Surfactant

Saturated or unsaturated hydrocarbons such as alkyl, benzyl, etc. in the chain terminal of the molecule and carboxyl, alcohol, sulfonyl, amide in the other terminal group All materials having a hydrophilic group such as), imine, phosphonyl and the like are referred to as substances which lower the surface tension such as surfactant, emulsifier (ionic, nonionic) and the like.

2. Hydrophilic Substance

Amide, alcohol, sulfonyl, carboxyl, imine, phosphonyl groups, etc., which have a double bond capable of generating radicals and exhibit hydrophilicity at the terminal group. Monomers, prepolymers of these monomers, and the like.

3. oxidizer

Oxidizers with oxygen donating ability, such as ammonium persulfate, (NH ₄ ) ₂ S ₂ O ₈ ), chromium oxide (K ₂ Cr ₂ O ₇ ), manganese peroxide (KMnO ₄ ), perchloric acid (KClO ₃ ) Collectively.

4. Initiator

As a polymerization initiator capable of radical polymerization, it includes all initiators having water-soluble properties. In particular, tetramethyl ethylene diamine is typically emulsified by making an initiator such as AIBN or benzoyl peroxide into an emulsion phase even if it is not water-soluble. It is available.

Referring to the method of the present invention in more detail according to the process as follows.

As the hydrophilic material, the acrylamide, which has high hydrophilicity and good hydrophobic polymer surface and graft copolymerizing, uses 1 ~ 50 (V / V) to form a network of radically copolymerized acrylamide. In order to obtain a uniform surface with methylene bis-acrylamide (methylene bis-acrylamide) is added 0.1 ~ 10% (V / V). Ammonium persulphate 0.01% (V / V) to 0.5 (V / V), which acts as an oxidizing agent to perform radical graft copolyemr directly at room temperature (5 to 60%) without using heat or photopolymerization The hydrophilic monomer acrylamide is oxidized and tetramethyl ethylene diamine (TMEDA) is added to 0.01% (V / V) to 0.5% (V / V) to initiate the reaction. The reaction rate is controlled according to the amount of oxidizing agent. As the amount of oxidizing agent is increased, the reaction can be completed for the required time at a desired temperature. Therefore, there are many advantages in terms of apparatus and cost compared to the conventional method.

Preferred polymerization time in the present invention is about 1 minute when the polymerization temperature is 5 ~ 60% is advantageous for productivity and process control.

Key features of the present invention compared to conventional methods are physical chemistry treatments: 1) using water as a solvent on the surface of the radical-generated polymer, and 2) using a surfactant to reduce the surface tension caused by the use of water. It is possible to improve the uniform coating, and 3) it is possible to enable graft copolymerization only by uniform coating at room temperature without using light or heat such as ultraviolet rays. Next, the present invention will be described in more detail with reference to preferred embodiments of the present invention. However, the various examples are provided only for better understanding of the present invention and the present invention is not limited to these embodiments.

Example 1

Corona discharge treatment was performed on the polyethylene sheet to generate radicals on the surface, and an aqueous hydrophilic monomer solution having the composition shown in Table 1 was immediately poured onto the surface-treated polyethylene sheet. For uniform application, a knife doctor was uniformized to a thickness of 0.1 mm 2 to 3 times and allowed to stand at room temperature (25 ° C or more) for 60 seconds. Upon completion of the graft copolymerization, the sheet was removed, and the sheet was gently washed with water to prepare an invincible polyethylene film.

[Examples 2 to 26]

Except for the composition of the hydrophilic monomer aqueous solution in Example 1 as shown in Table 1 to Table 3 was treated in the same manner as in Example 1.

TABLE 1

Examples of Graft Copolymerization for Affinity Modification of Polyethylene Surfaces

* BPObenzoyl peroxide

TMEDA: tetramethylethylenediamine

AIBN: Azobisisobutylonitrile

TABLE 2

Examples of the formulation of ghrpart copolymerization for hydrophilic modification of polyethylene terephthalate surface

TABLE 3

Formulation Examples of Graft Copolymerization for Hydrophilic Modification of Polymethylmethacrylate Surfaces

Comparative Example 1

A product (vinyl house) and a hydrophilized polymer sheet made in the present invention were mixed by distilling water into a film form by mixing a conventionally used surfactant and polyethylene, and the temperature was raised to 60-70 ° C. and unreacted for 2 days. Wash and remove. Fill a 300 ml beaker with 100 ml of water, heat it to 50-60 ° C, and seal the top with a test polymer sheet. Table 4 shows the results of measurement of non-production according to surface modification.

TABLE 4

Invincibility Duration

Comparative Example 2

The polyethylene film for commercial vinyl house (invincible film) and the sample of the present invention were pretreated in the same manner as in Example 1, the polymer for the sample was placed on gonier meta, and the drop of water was measured. .

TABLE 5

Claims (10)

Hydrophobic polymer materials are treated by chemical, physical, or optical means to generate radicals on the surface of hydrophobic polymers, hydrophilic substances with a double bond capable of forming radicals and hydrophilic functional groups at the end groups, surfactants, oxidants and An aqueous solution containing a radical polymerization initiator is applied to the surface of the radical-forming hydrophobic polymer so that a hydrophilic material having a double bond capable of forming radicals and a hydrophilic functional group at the terminal is graft copolymerized with the surface of the hydrophobic polymer. Hydrophilic Surface Modification of Hydrophobic Polymers. The surfactant according to claim 1, wherein the surfactant has a saturated or unsaturated hydrocarbon such as an alkyl group or a benzyl group at one terminal of the molecular chain and a carboxyl group, alcohol group, sulfonyl group, amide group, amine group, or phosphate group at the other terminal group. A material having a hydrophilic group, such as an anionic, cationic, nonionic, or bipolar surfactant. The method of claim 1 wherein water is used as the solvent for the hydrophilic monomers. The method according to claim 1, wherein the hydrophobic polymer is a thermosetting or thermoplastic hydrophobic polymer material such as polyethylene, polyethylene terephthalate, polycarbonate, polymethyl methacrylate, and the like. The method of claim 1, wherein the hydrophilic material is a material containing an amide group, an alcohol group, a sulfonyl group, a carboxyl group, an amine group, or a phosphoric acid group having a double bond capable of generating radicals and exhibiting hydrophilicity at an end group. How to. The method of claim 1, wherein the oxidizing agent is a material having an oxygen donating ability such as ammonium persulfate, chromium oxide, manganese peroxide, or perchloric acid. The method according to claim 1, wherein the initiator is an initiator of radical polymerization selected from the group consisting of benzoyl peroxide, petramethylethylenediamine and azobisisobutylonitrile having water-soluble properties. The method of claim 1 wherein the aqueous solution further comprises a crosslinking agent represented by methylenebisacrylamide. The method of claim 1, wherein the polymerization of the hydrophilic material is carried out at 5 to 60 ℃. 10. The process according to claim 1 or 9, wherein the polymerization of the hydrophilic substance is carried out in about 1 minute.