JPH05255453A - Production of fluorine-containing acrylic resin - Google Patents

Abstract

PURPOSE:To obtain a new fluorine-containing resin bearing comparison with a conventional fluorine-containing resin by copolymerizing an alkyl acrylate, etc., with a fluoroalkyl acrylate, etc., and glycidyl acrylate, etc., in solution. CONSTITUTION:(A) 50-80mol% one or more mixtures from an alkyl acrylate and an alkyl methacrylate is copolymerized in solution with (B) 15-30mol% one or more mixtures from a fluoroalkyl acrylate and a fluoroalkyl methacrylate and (C) 5-20mol% one more mixtures from glycidyl acrylate, glycidyl methacrylate, tetrahydrofuryl acrylate and tetrahydrofuryl methacrylate in a solvent in the presence of a polymerization initiator to give the objective resin having 80,000-150,000 molecular weight and 30-60 deg.C glass transition point.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a fluorine-containing acrylic resin, and more particularly to a method for producing a fluorine-containing acrylic resin useful as a top coating for an outer wall elastic finish structure.

[0002]

2. Description of the Related Art Conventionally, fluororesins are excellent in light resistance, heat resistance, chemical resistance, etc., so that paints containing these resins as a main component have been recently used in various industrial fields. It is now being put to practical use. However, in general, fluoropolymer homopolymers or copolymers such as perfluoroethylene, chlorotrifluoroethylene, and perfluoropropylene are often used as fluororesins, but these are insoluble in organic solvents and need to be heated and melted during coating. Therefore, there is a difficulty in workability,
Alternatively, there is a problem of high material cost. Therefore, a modified fluororesin prepared by copolymerizing a fluoroolefin with vinyl chloride, vinyl acetate, alkyl acrylate, alkyl methacrylate, etc. has been proposed, but it has a difficulty in adhesion to the base in coating applications, and the resulting coating film Since it is hard, it is not possible to follow the case where vibration or expansion and contraction behavior of the substrate occurs, and defects such as cracks on the surface of the coating film and peeling occur.

On the other hand, in the finish coating on the outer wall material of the building, in addition to the aesthetic properties and the protection of the base, especially the waterproof function.
(That is, the coating film follows the vibration and the expansion and contraction displacement to avoid the occurrence of the above-mentioned coating film defects, thereby obtaining the waterproof effect). An object of the present invention is to create a new fluorine-containing resin which is comparable to the excellent attributes of conventional fluororesins and modified fluororesins, and to develop its use as a paint.

[0004]

Means for Solving the Problems As a result of intensive research aimed at achieving such an object, the present inventors have found that fluorine-containing acrylic monomers and glycidyl are added to alkyl acrylates and alkyl methacrylates which are commonly used in acrylic resins. Acrylic monomer containing tetrahydrofuryl or tetrahydrofuryl can be solution-copolymerized to obtain the desired fluororesin, and if the resin is made into a paint, it can be used as a base adhesive without impairing the weather resistance of the fluororesin. The inventors have found that the properties are improved and that elasticity can be imparted, and have completed the present invention.

That is, the present invention comprises (a) 50-80 mol% of a mixture of one or more selected from the group of alkyl acrylates and alkyl methacrylates, and (b) a group of fluoroalkyl acrylates and fluoroalkyl methacrylates. 15 to 30 mol% of a mixture of one or more selected, and (c) glycidyl acrylate,
5 to 20 mol% of one or a mixture of two or more selected from the group of glycidyl methacrylate, tetrahydrofuryl acrylate and tetrahydrofuryl methacrylate
By solution-copolymerizing and, a molecular weight of 80,000 to 1
The present invention provides a method for producing a fluorine-containing acrylic resin, which comprises obtaining a fluorine-containing acrylic resin having a glass transition point of 50,000 and a glass transition point of 30 to 60 ° C.

The production method of the present invention comprises: (a) one or a mixture of two or more selected from the group of alkyl (meth) acrylate (hereinafter, (meth) acrylate refers to acrylate and methacrylate); b) fluoroalkyl
Solution of one or more mixture selected from the group of (meth) acrylate and one or more mixture selected from the group of (c) glycidyl (meth) acrylate and tetrahydrofuryl (meth) acrylate It is carried out by copolymerization. In addition, such essential monomers (a to c)
Besides, acrylic acid and / or methacrylic acid may be copolymerized if necessary.

Specific examples of the above-mentioned (a) monomer alkyl (meth) acrylate include methyl (meth) acrylate,
Ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl acrylate, hexyl acrylate,
2-ethylbutyl acrylate, pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl acrylate,
Examples thereof include nonyl acrylate. In particular, it is preferable to appropriately select and combine a monomer imparting a high glass transition temperature and a monomer imparting a low glass transition temperature, respectively, to adjust the glass transition temperature of the target resin to a desired range. The copolymerization ratio of the monomer (a) is set so as to be 50 to 80 mol%, preferably 60 to 75 mol% in all the monomers. With this ratio, it is possible to impart elasticity without impairing the characteristics of the fluorine atom contained in the target resin, and it is advantageous from the economical point of view.

Specific examples of the fluoroalkyl (meth) acrylate as the monomer (b) include 2,2,2-trifluoroethyl (meth) acrylate and 2,2,3,3-tetrafluoropropyl (meth) acrylate. 1H, 1H, 5
H-octafluoropentyl (meth) acrylate, 1
H, 1H, 2H, 2H-heptadecafluorodecyl (meth)
Examples thereof include acrylates, and 2,2,3,3-tetrafluoropropyl acrylate and 1H, 1H, 5H-octafluoropentyl acrylate are particularly preferable. Take
(b) Monomers, like conventional fluoroolefins, reduce surface energy due to their fluorine atoms, which is effective in reducing dust adhering to the surface of the coating film and preventing fouling. Can be made difficult to get wet and the water-repellent function can be improved. The copolymerization ratio is
15 to 30 mol% of all monomers, preferably 20 to 25
Set it so that it is mol%. This ratio is advantageous from the viewpoint of combining the above-mentioned effects of the monomer with economy.

The above-mentioned monomer (c) improves the adhesion of the objective resin to the substrate, and the copolymerization ratio thereof is 5 to 20 mol%, preferably 7 to 15 mol% of the total monomers.
To be set. Since the glycidyl group or the tetrahydrofuryl group of the monomer (c) can cause a ring-opening reaction or a cross-linking reaction, it contributes not only to the improvement of the above-mentioned adhesiveness but also to the physical properties of the coating film. In particular, in the case of adding a commonly used additive such as a pigment when the target resin is made into a coating material, the reliability of the adhesiveness is improved by setting the copolymerization ratio of the monomer to 10 to 20 mol%.

Acrylic acid and methacrylic acid, which are copolymerized as necessary, are used for adjusting the hardness and glass transition temperature of the target resin or for cost reduction. However, if they are too much, the chemical resistance decreases. Usually, the copolymerization ratio may be set to 10 mol% or less in all monomers.

The above solution copolymerization is carried out in a reaction solvent in the presence of a polymerization initiator at a predetermined ratio of the copolymerization monomer, usually 70 to 10
It is carried out by heating and stirring (until the residual unreacted monomer becomes 0.5% by weight or less) at a temperature of 0 ° C. for 4 to 24 hours. In this case, the solid content in the reaction solvent is 30 to 60% by weight.
If set to, gelation during polymerization can be prevented. Examples of the reaction solvent include ketones (methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), ester (ethyl acetate, cellosolve acetate, etc.), aromatics (toluene, xylene, etc.), alcohols (n-butanol, methyl cellosolve). , Butyl cellosolve, etc.), and methyl ethyl ketone and ethyl acetate are particularly preferable from the viewpoint of decreasing the viscosity of the solution copolymer. Examples of the polymerization initiator include benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, dicumyl peroxide, di-t-butyl peroxide, t-butyl peroxide. Examples thereof include acetate, acetyl peroxide, azobisisobutyronitrile and the like. The amount of the polymerization initiator used may be appropriately set depending on the type and the polymerization conditions, and is usually 0.
It may be selected in the range of 01 to 5% by weight, and since it is necessary to increase the molecular weight in order to obtain the desired elasticity, 0.1 to 1.
0% by weight is preferred.

The fluorine-containing acrylic resin produced in this manner is described in G. P. C. Molecular weight by method 80000-
150000, glass transition temperature 30 by differential thermal analysis
It has a temperature of -60 ° C and can be used for top coatings for outer wall elastic finish structures.

[0013]

EXAMPLES Next, the present invention will be described more specifically with reference to examples. In the example sentence, "part" means "part by weight". Examples 1 to 7 Copolymer monomers, reaction solvents (toluene, ethyl acetate) and polymerization initiator (benzoyl peroxide) in the amounts shown in Tables 1 and 2 below were precisely weighed, and these were placed in a reaction vessel under a nitrogen atmosphere, The mixture is heated and stirred at 80 ° C. for 8 hours to obtain a fluorine-containing acrylic resin. The molecular weight and glass transition temperature of such resins are also shown in Tables 1 and 2.

[Table 1]

[Table 2]

Claims (1)

[Claims] 1. A compound selected from the group consisting of (a) an alkyl acrylate and an alkyl methacrylate, and 50 to 80 mol% of a mixture of two or more thereof, and (b) one selected from the group of a fluoroalkyl acrylate and a fluoroalkyl methacrylate. Alternatively, 15 to 30 mol% of a mixture of two or more kinds, and one or two kinds selected from the group of (c) glycidyl acrylate, glycidyl methacrylate, tetrahydrofuryl acrylate and tetrahydrofuryl methacrylate.
A method for producing a fluorine-containing acrylic resin, characterized in that a fluorine-containing acrylic resin having a molecular weight of 80,000 to 150,000 and a glass transition point of 30 to 60 ° C. is obtained by solution copolymerizing 5 to 20 mol% of a mixture of one or more kinds. ..