JP3001230B2 - Method for producing fluorine-containing polyester - Google Patents

Description

The present invention relates to a novel method for producing a fluorine-containing polyester.

[Prior Art] Polyester resin paints are widely used for general building materials, outer walls, embossed steel plates and the like because of their hard coating films and excellent workability and thick coating properties. However, the long-term weather resistance of the coating film is not sufficient, and its improvement is required.

On the other hand, fluorine-containing resin coatings have been growing in demand in recent years, taking advantage of their properties such as long-term weather resistance, water and oil repellency, chemical resistance, and non-adhesion.

[Problems to be Solved by the Invention] As methods for improving the weather resistance and water / oil repellency of the polyester resin, 1) blending with a fluororesin paint, 2) introduction of a fluorine atom into the polyester resin skeleton, and the like are considered. The former has a problem that the compatibility between the two is small, and the latter has a problem that fatty acids and alcohols, which are raw materials of the polyester resin, are expensive and difficult to employ industrially.

An object of the present invention is to provide an inexpensive method for producing a fluorine-containing polyester, which has not been known so far.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and includes a radical polymerizable fluorine-containing monomer and a compound represented by the general formula [I]: It is intended to provide a process for producing a fluorine-containing polyester, which comprises copolymerizing a cyclic monomer having a vinylidene group represented by (A represents an organic group) in the presence of a radical polymerization initiation source.

Examples of the radical polymerizable fluorine-containing monomer used in the present invention include fluorine-containing olefins such as tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, and perfluorovinyl ether; and CH ₂ CHCHC
O ₂ R _f or fluorinated acrylate or methacrylate represented by CH ₂ ＣC (CH ₃ ) CO ₂ R _f (R _f is a fluoroalkyl group) (hereinafter collectively referred to as fluorinated (meth) acrylic) Abbreviated as acid ester),
Examples include fluorine-containing carboxylic acid vinyl esters represented by R _{f ′} CO ₂ CH ＝ CH ₂ (R _{f ′} is a fluoroalkyl group).

When the performance such as weather resistance, durability, and recoatability of a coating film is particularly desired for the produced fluorine-containing polyester, it is preferable to employ a fluorine-containing olefin. The fluorine-containing olefin is a compound having a fluorine-substituted ethylenically unsaturated group, and includes, in addition to the above, vinylidene fluoride, vinyl fluoride, trifluoroethylene, and the like.
In particular, when weather resistance is required, it is preferable to employ a compound having a completely fluorine-substituted ethylenically unsaturated group or a fluorinated perhaloolefin.

In addition, when water repellency and oil repellency are particularly desired for the fluorine-containing polyester to be produced, it is preferable to employ a fluorine-containing (meth) acrylate or a fluorine-containing vinyl carboxylate. Particularly, a compound having a perfluoroalkyl group having about 1 to 20 carbon atoms is preferably employed because it provides excellent water repellency and oil repellency. Further, as the fluorinated (meth) acrylic acid ester, those in which R _f in the above formula is a 2-perfluoroalkylethyl group are preferably employed from the viewpoint of easy production and availability.

In the present invention, the radical-polymerizable fluorine-containing monomer is represented by the general formula [I]: It is important to copolymerize a cyclic monomer having a vinylidene group represented by (A is an organic group). Since the cyclic monomer is bonded to a vinylidene group and has an oxygen atom constituting a part of a ring, an ester group is formed by radical transfer during copolymerization (a presumed reaction mechanism will be described later).
It is. As such a cyclic monomer, from the viewpoint of production, stability, and availability, A in the above general formula [I]
Is preferably an alkylene group having 2 to 10 atoms constituting the ring or an alkylene group having ethereal oxygen between carbon-carbon bonds in the alkylene group. Further, such an alkylene group or an alkylene group having an etheric oxygen between carbon-carbon bonds in the alkylene group is at least one of a functional group such as an alcoholic hydroxyl group and an ester bond, a fluorine atom, a chlorine atom, and an alkyl group. The part may be substituted. Particularly preferred A is an alkylene group or an oxyalkylene group having 2 to 5 atoms constituting a ring.

Specific examples of such cyclic monomers include 2-methylene-
1,3-dioxolan, 2-methylene-1,3-dioxane,
2-methylene-1,3-dioxepane and the like.

These fluorine-containing monomers and cyclic monomers having a vinylidene group are usually subjected to copolymerization at a ratio of 5 to 95 and 95 to 5 mol%, respectively. Copolymerization outside the above range causes disadvantages in terms of weather resistance or water / oil repellency, non-adhesion, solvent solubility, and production.

In the present invention, in addition to the above-mentioned radical polymerizable fluorine-containing monomer and the cyclic monomer having a vinylidene group, an ethylenically unsaturated monomer copolymerizable therewith may be copolymerized. The other copolymerizable ethylenically unsaturated monomer is not particularly limited, but when polyester is used as a coating material, its solubility in a solvent, control of coating film hardness, and weather resistance are taken into consideration. Vinyl esters and vinyl ethers are preferred. In order to improve the toughness and solvent resistance of the coating film by introducing a cured site, the use of a curable functional group-containing monomer such as a hydroxyl group-containing alkyl vinyl ether or alkoxyvinyl silane is strongly recommended.

On the other hand, when the polyester is used as a non-adhesive coat or a water / oil repellent material, a fluorine-containing acrylic (methacryl) is used.
Butyl acrylate (methacrylate) and ethyl acrylate (methacrylate), which are highly copolymerizable with acid esters
And the like, and hydroxyethyl acrylate (methacrylate) or the like can be used as a curing component.

The unit based on the monomer is 40 units more than the unit based on the fluorine-containing monomer and the cyclic monomer having a vinylidene group.
It is preferable that the content is not more than the mol% in order not to impair the properties of the coating film.

In the copolymerization in the present invention, the cyclic monomer having a vinylidene group tends to cause decomposition or homocationic polymerization in an acidic state, and to promote the polymerization stably, under basic conditions, particularly at pH 8 to 10. About 9 is preferable.
Examples of the radical polymerization initiator include a radical polymerization initiator and ionizing radiation. Here, as the polymerization initiator, a water-soluble one or an oil-soluble one can be appropriately used depending on the polymerization type or the polymerization medium. Specifically, as the water-soluble initiator, a redox initiator composed of a persulfate such as potassium persulfate, hydrogen peroxide or a combination thereof with sodium hydrogen sulfite and a reducing agent such as sodium thiosulfate, Inorganic initiators such as those in which a small amount of iron, ferrous salt, silver nitrate and the like coexist, or dibasic acid peroxides such as disuccinic peroxide, diglutaric peroxide, monosuccinic peroxide, azobisisobutylamidine Organic initiators such as dihydrochloride, and oil-soluble initiators include peroxyester-type peroxides such as t-butylperoxyisobutyrate and t-butylperoxyacetate, and diisopropylperoxydicarbonate. , Bezoyl peroxide, azobisisobutyronitrile and the like. The amount of the polymerization initiator used can be appropriately changed depending on the kind, copolymerization reaction conditions, etc., but is usually 0.005 to 5% by weight, particularly 0.05% by weight, based on the total amount of the monomers to be copolymerized.
About 0.5% by weight is adopted.

In the above copolymerization reaction, the reaction mode is not particularly limited, and bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization, and the like can be adopted, but the stability of the polymerization reaction operation, the separation of the produced copolymer, and the like. From the viewpoint of easiness and the like, emulsion polymerization in an aqueous medium or aromatic compounds such as xylene and toluene, alcohols such as t-butanol, esters, and saturated halogenated hydrocarbons containing at least one fluorine atom are used as solvents. Solution polymerization or the like is preferably adopted. When the copolymerization reaction is carried out in an aqueous medium, it is preferable to add a basic buffer so that the pH value of the solution during the polymerization does not fall below 7, preferably 8. The addition of a basic substance is also effective in the case of solution polymerization. Also, the method of the present invention comprises:
Of course, it can be performed by a batch type, semi-continuous type, continuous type or the like.

In such a copolymerization reaction, the copolymerization reaction temperature is −30 ° C.
The optimum value can be appropriately selected depending on the type of the polymerization initiation source, the type of the polymerization medium and the like within the range of from -150 ° C., but 0 ° C. to + 100 ° C., preferably 10 C. to about 90.degree. C. can be employed. The reaction pressure is
Although it can be selected as appropriate, it is usually 1 to 100 kg / cm ² , especially 2 kg / cm ² .
It is desirable to employ about 50 kg / cm ² .

Further, in order to keep the intrinsic viscosity of the produced copolymer within the above range, it is possible to appropriately carry out the copolymerization reaction in the presence of a chain transfer agent.

The polyester according to the present invention, when a hydroxy group, an epoxy group, or the like is introduced as a curing site in the copolymer, is cured at about 0 to 250 ° C. using a general curing agent to form a coating film having a crosslinked structure. Can be formed.

When the polyester according to the present invention is used as a paint base, it has excellent surface hardness, gloss and flexibility, excellent solvent resistance, excellent stain resistance, and excellent weather resistance. Can be given below,
It is useful not only as a baking paint for color steel plates, color aluminum plates, aluminum sashes, etc., but also as a normally dry paint that can be installed on site. The material of the base material is not limited to metal, but it is glass, cement, concrete Inorganic materials such as FR
P, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, nylon, acrylic, polyester, ethylene-polyvinyl alcohol copolymer, polyvinyl chloride, polyvinylidene chloride and other plastics, and extremely useful for coating organic materials such as wood It is. They are also useful in certain applications such as aluminum pools, exterior colored glass, cement roof tiles, and the like.

On the other hand, when the copolymer of the present invention is used as a surface modifier, particularly when a fluorine-containing (meth) acrylate or a vinyl carboxylate is used as a radically polymerizable fluorine-containing monomer, excellent results are obtained. Water and oil repellency,
It is possible to give non-stickiness and antifouling property. The material of the base material is not particularly limited, and examples thereof include fiber woven fabric, plastic, metal, cement, and concrete. As a fiber,
Examples include natural fibers such as cotton, hemp, wool, and silk; synthetic fibers such as polyester, polyamide, and polyvinyl chloride; and inorganic fibers such as glass and asbestos fibers.

[Function] Since the copolymer of the present invention has a polyester structure as shown in the examples, the cyclic monomer having a vinylidene group represented by the general formula [I] can form a polymerization reaction mechanism shown in the following scheme. Is considered to be polymerized.

[Example] Example 1 In an autoclave (withstand pressure of 30 kg / cm ² ) having a stainless steel stirrer having an internal volume of 80 cc, 16.7 g (46.8 mol%) of 2-methylene-1,3-dioxepane [2M13Dp], 21.9 g of xylene, and ethanol 6.2 g, potassium carbonate 0.41 g, and azobisisobutyronitrile 0.03 g are charged, and dissolved air is removed by solidification and degassing with liquid nitrogen. Thereafter, 19.8 g (53.2 mol%) of chlorotrifluoroethylene [CTFE] is introduced into the autoclave, and the temperature is raised. The temperature in the autoclave is 65
When the temperature reaches ° C, the pressure shows 6.0 kg / cm ² G. Thereafter, the reaction was continued under stirring for 3 hrs. When the pressure dropped to 5.2 kg / cm ² G, the autoclave was cooled with water to stop the reaction. After reaching room temperature, unreacted monomers are purged and the autoclave is opened. After pouring the obtained polymer solution into water to precipitate the polymer, washing and drying are performed to recover the polymer. The polymer yield was 14.9 g and the monomer conversion was 40.8%. The obtained polymer has rubber elasticity and intrinsic viscosity (in tetrahydrofuran at 30 ° C.) (“η]) of 0.12 dl / g
Met. As a result of elemental analysis of the obtained polymer, the fluorine content was 10.4 wt%, and the copolymer composition calculated based on the fluorine content was CTFE / 2M13Dp = 21.0 / 79.0 mol%. FIG. 1 shows the IR spectrum of the copolymer.

At 1725 cm ^-1 , strong absorption of an ester bond generated by ring-opening polymerization of 2M13Dp is observed. In addition, strong absorption of CF bond is observed at 1100 to 1200 cm ^-1 .

Examples 2 to 5 Polymerization was carried out under the same conditions as in Example 1. Table 1 shows the conditions and results.

Example 6 In a 50 cc three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, heptadecafluoroethyl acrylate (C ₈ F ₁₇ CH ₂ CH ₂ OCO
CH = CH ₂ Mw 518.2, hereinafter abbreviated as FA-8) 4.9 g (11.5
8.3 g (88.5 mol%) of 2M13D, ethyl acetate 8.
3 g, 0.154 g of azobisisobutyronitrile, 70-80
The mixture was stirred at room temperature for 18 hours under a nitrogen atmosphere. As the reaction proceeded, a grease-like polymer was precipitated from the solution. The resulting polymer was separated, washed with ethyl acetate and dried in vacuum. The polymer yield was 5.0 g and the conversion of the monomer was 37.9%. As a result of elemental analysis of the copolymer, its fluorine content was 27.5.
wt%, and the copolymer composition calculated based on this was FA-
8 / 2M13Dp = 14.9 / 85.1 mol%. FIG. 2 shows the IR spectrum of the copolymer.

Absorption of an ester bond of an acrylate ester is observed at 1720 cm ⁻¹ , and absorption of an ester bond accompanying ring opening of 2M13Dp is observed around 1730 cm ⁻¹ .

Examples 7 to 10 Polymerization was carried out under the same conditions as in Example 6.

 Table 2 shows the conditions and results.

Example 11 2-methylene-1,3-dioxepane [2M13Dp] 5.4 g (30 mol%) hydroxybutyl vinyl ether [HBVE] 4.2 g, xylene in an autoclave (withstand pressure 30 kg / cm ² ) with a stainless steel stirrer having an internal volume of 80 cc 30.3 g, 8.5 ethanol
g, potassium carbonate 0.24 g, azobisisobutyronitrile 0.
02g is charged and dissolved air is removed by solidification with liquid nitrogen and degassing. Thereafter, 10.7 g (50 mol%) of chlorotrifluoroethylene [CTFE] is introduced into the autoclave and heated. When the temperature in the autoclave reaches 65 ° C., the pressure shows 3.4 kg / cm ² G. Thereafter, the reaction was continued under stirring for 20 hrs. When the pressure dropped to 0.2 kg / cm ² G, the autoclave was cooled with water to stop the reaction. After reaching room temperature, unreacted monomers are purged and the autoclave is opened. After pouring the obtained polymer solution into water to precipitate the polymer, washing and drying are performed to recover the polymer. The polymer yield was 15.2 g and the monomer conversion was 75.0%. Intrinsic viscosity of the obtained polymer (30 in tetrahydrofuran,
° C) ([η]) is 0.12 dl / g and the glass transition temperature (DS
C at a rate of 10 ° C./min) was 15 ° C.

From the ¹³ C-nmr measurement results of this copolymer, CTFE / 2M13Dp / HB
The molar ratio of VE was 39.0 / 41.0 / 20.0. 10 g of the present copolymer
Was dissolved in 10 g of xylene and 5 g of MIBK, and 4.2 g of titanium oxide (CR-90 manufactured by Ishihara Sangyo) was added, followed by mixing for 1 hour using a paint shaker. 0.8 g of hexamethylene diisocyanate and 1.5 × 10 ⁻⁷ g of dibutyltin dilaurate were added to the obtained paint, which was applied to a chromate-treated aluminum plate using an applicator. After 3 days at room temperature, a solid cured film is obtained
Results of JIS and various tests that are usually conducted Table 3
Was obtained.

[Effect of the Invention] The copolymer obtained by the method of the present invention has excellent weather resistance, water and oil repellency, chemical resistance, and non-adhesiveness, and when the copolymer is used as a coating material, A paint excellent in weather resistance and coating processability can be manufactured. On the other hand, when used as a surface modifier, the surface non-adhesiveness of various fibers is improved,
The effect is recognized to improve the water and oil repellency.

[Brief description of the drawings]

FIG. 1 is a diagram of an IR spectrum of the polymer obtained in Example 1. FIG. 2 is an IR spectrum of the polymer obtained in Example 6.

Claims (2)

(57) [Claims] 1. A radically polymerizable fluorine-containing monomer and a compound represented by the general formula [I]: A method for producing a fluorine-containing polyester, comprising copolymerizing a cyclic monomer having a vinylidene group represented by (A represents an organic group) in the presence of a radical polymerization initiation source. 2. A radically polymerizable fluorine-containing monomer and a compound represented by the general formula [I]: Wherein a cyclic monomer having a vinylidene group represented by (A represents an organic group) and an ethylenically unsaturated monomer copolymerizable therewith are copolymerized in the presence of a radical polymerization initiation source. A method for producing a fluorinated polyester.