JPH07238116A - Carboxylated fluorocopolymer and its production - Google Patents

Abstract

PURPOSE:To provide a carboxylated fluorocopolymer useful for preparing a coating composition which has a good storage stability and gives a good coating film even after stored for a long time. CONSTITUTION:A carboxylated fluorocopolymer comprises units derived from a fluoroolefin, units derived from a vinyl ether having no hydroxyl nor carboxyl group, units derived from a hydroxylated vinyl ether, and units derived from a 5C or higher unsatd. carboxylic acid other than a carboxylated vinyl ether.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a carboxyl group-containing fluorocopolymer and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, there are many cases in which an acid anhydride / acid imide compound is introduced into a polymer substance to improve / introduce adhesiveness, polymer reactivity, dyeability, pigment affinity, ion exchangeability, etc. There are many examples of industrialization of general polymer substances.

On the other hand, as a method for producing a carboxyl group-containing fluorine-containing copolymer, (A) a hydroxyl group-containing fluorine-containing copolymer is reacted with a dibasic acid anhydride in an organic medium, and at least a part of the hydroxyl groups is carboxyl-containing. A method of converting to an ester group has been proposed.

Further, (B) Japanese Unexamined Patent Publication (Kokai) No. 2-58555 proposes a method for producing a carboxyl group-containing fluorine-containing copolymer by copolymerizing vinyl ethers having a carboxyl group with a fluoroolefin.

[0005]

The method (A) is problematic in that it has an ester structure in the formed structure, there is a risk of hydrolysis, and the type of dibasic acid anhydride is limited. Had. In addition, the method (B) has a problem that when a vinyl ether having a carboxyl group is copolymerized, a side reaction occurs during the production of the fluorine-containing copolymer, such as decomposition of the vinyl ether.

[0006]

The present invention relates to a carboxyl group-containing fluorine-containing copolymer which does not have the above-mentioned problems and a method for producing the same, which comprises (a) a polymerized unit based on a fluoroolefin and (b) a hydroxy unit. Group- or carboxyl group-free vinyl ether-based polymerized unit, (c) hydroxy group-containing vinyl ether-based polymerized unit, and (d) C5 or more unsaturated-carboxylic acid-containing vinyl ether other than carboxyl group-containing vinyl ether Carboxyl group-containing fluorinated copolymer containing a unit and (a ') fluoroolefin, (b')
In the presence of (e) a basic compound, an unsaturated carboxylic acid other than a vinyl ether having no hydroxy group or a carboxyl group, (c ') a hydroxy group-containing vinyl ether, and (d') a vinyl ether having 5 or more carbon atoms and a carboxyl group The present invention provides a method for producing a carboxyl group-containing fluorocopolymer, which is characterized by copolymerization.

As the (a ') fluoroolefin constituting the fluorinated copolymer containing a carboxyl group of the present invention, CF ₂ = CR ₁
R ₂ (R ₁ : H, F or Cl, R ₂ : H, F, Cl or a fluoroalkyl group having 1 to 3 carbon atoms) is preferable, and CClF = CF ₂ , CHCl = CF ₂ , CCl ₂ = CF ₂ , CClF = CC
Fluoroethylenes such as lF, CHF = CCl ₂ , CH ₂ = CClF, CCl ₂ = CClF, CF ₂ = CF ₂ , CF ₂ = CH ₂ , CF ₂ ClCF = CF ₂ , CF ₂ CCl = CF ₂ , CF ₂ CF = CF
Cl, CF ₂ ClCCl = CF ₂ , CF ₂ ClCF = CFCl, CFCl ₂ CF = CF ₂ , CF ₃ CCl = CC
lF, CF ₃ CCl = CCl ₂ , CClF ₂ CF = CCl ₂ , CCl ₃ CF = CF ₂ , CF ₂ ClCCl = CC
l ₂ , CFCl ₂ CCl = CCl ₂ , CF ₃ CF = CHCl, CClF ₂ CF = CHCl, CH ₃ CCl = CH
Cl, CHF ₂ CCl = CCl ₂ , CF ₂ ClCH = CCl ₂ , CF ₂ ClCCl = CHCl, CCl ₃ CF =
_{CHCl, CCl 3 CF = CHCl,} CHBrCF = CCl 2, CF 2 = CFOCF 3, CF 2 = CFOC 3 F
Fluoropropenes such as ₇ CF ₃ CCl = CFCF ₃ , CF ₂ = CFCF ₂ CC
Fluoroolefins having 4 or more carbon atoms such as lF ₂ , CF ₃ CF ₂ CF = CCl _{2 and the} like. These fluoroolefins may be used alone or in combination of two or more.

Examples of the vinyl ether (b ') containing no hydroxy group or carboxyl group include methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, octyl vinyl ether, neopentyl vinyl ether, t-butyl vinyl ether, α, α'-. Aliphatic alkyl vinyl ethers such as dimethyl propyl ether, alicyclic alkyl vinyl ethers such as cyclohexyl vinyl ether, aromatic vinyl ethers such as phenyl vinyl ether, benzyl vinyl ether and naphthyl vinyl ether, methyl isopropenyl ether, ethyl isopropenyl ether, propyl isopropenyl Isopropenyl such as ether, butyl isopropenyl ether, cyclohexyl isopropenyl ether Such ethers may be mentioned, may be used alone or two or more thereof.

The hydroxy group-containing vinyl ether (c ') includes 2-hydroxyethyl vinyl ether and 3-hydroxyethyl vinyl ether.
Hydroxyalkyl vinyl ethers such as hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 9-hydroxynonyl vinyl ether, 1-hydroxymethyl-4-vinyloxymethyl cyclohexane and 3-chloro-2-hydroxypropyl vinyl ether, 2-hydroxyethyl isopropenyl Ether, 3
-Hydroxypropyl isopropenyl ether, 4-hydroxybutyl isopropenyl ether, 9-hydroxynonyl isopropenyl ether, 1-hydroxymethyl-4-isopropenoxymethylcyclohexane, 3-
Examples include hydroxyalkyl isopropenyl ethers such as hydroxy-2-chloropropyl isopropenyl ether.

(D ') unsaturated carboxylic acids other than vinyl ethers having 5 or more carbon atoms and having a carboxyl group include itaconic acid, crotonic acid, allyloxypropionic acid, 3-butenoic acid, 4-pentenoic acid, 2- Hexenoic acid,
3-hexenoic acid, 5-hexenoic acid, 2-heptenoic acid, 3
-Heptenoic acid, 3-octenoic acid, 2-nonenoic acid, 3-nonenoic acid, 9-decenoic acid, 10-undecenoic acid, 2-tridecenoic acid. You may use these 2 or more types together.

In addition to the above-mentioned comonomers, other copolymerizable monomers may be copolymerized within the range in which the characteristics of the fluorine-containing copolymer are not lost. The following monomers can be exemplified. Olefins such as ethylene, propylene and isobutylene, haloolefins such as vinyl chloride and vinylidene chloride, vinyl acetate, vinyl butyrate, vinyl pivalate, vinyl benzoate, vinyl carboxylates such as vinyl versatate, allyl formate and allyl butyrate. , Allyl benzoate, allyl carboxylates such as cyclohexane allyl carboxylate,
Examples thereof include allyl ethers such as allyl ethyl ether and allyl phenyl ether, and (meth) acrylic acid esters such as ethyl acrylate and methyl methacrylate.

The fluorine-containing copolymer of the present invention has a number average molecular weight of 2,000 to 100,000, preferably 6,0.
Those having a molecular weight distribution of 00 to 30,000 and a molecular weight distribution of 4.0 or less, preferably 3.0 or less are suitable. Molecular weight is 2,
If it is less than 000, the weather resistance and chemical resistance are poor, and 100,00
If it exceeds 0, the viscosity of the coating material is high and there is a problem in dispersibility in water. Similarly, when the molecular weight distribution exceeds 4, a problem appears in the long-term stability of the coating material.

The copolymerization ratio of (a), (b), (c) and (d) is (b) 30 to 1 with respect to 100 mol of (a).
50 mol, (c) 3 to 100 mol and (d) 3 to 10
0 mol is preferred, and likewise (a ′), (b ′),
The copolymerization ratio of (c ') and (d') is (a ') 100.
30 to 150 moles of (b ') and (c') 3 with respect to moles
-100 mol and (d ') 3-100 mol are preferred.

The copolymer of the present invention is a copolymerization reaction in which a polymerization initiator or a polymerization initiation source such as ionizing radiation is allowed to act on a monomer mixture in a predetermined ratio in the presence or absence of a polymerization catalyst. It can be manufactured by carrying out. Further, in order to keep the copolymerization reaction system on the alkaline side, it is important to polymerize in the presence of a basic compound.

As the polymerization initiator, a water-soluble one or an oil-soluble one can be appropriately used depending on the type of polymerization or the polymerization medium.

Specifically, as the water-soluble initiator, a persulfate such as potassium persulfate, hydrogen peroxide or a redox initiator comprising these and a reducing agent such as sodium bisulfite and sodium thiosulfate, and further these Inorganic initiators such as those in which a small amount of iron, ferrous salt, silver nitrate, etc. coexist, or dibasic acid oxides such as disuccinic acid peroxide, diglutaric acid peroxide, and monosuccinic acid peroxide, azobisisobutylamidine dibasic Organic initiators such as acid salts, and as the oil-soluble initiator,
peroxyester type peroxides such as t-butyl peroxyacetate, dialkyl peroxydicarbonates such as diisopropyl peroxydicarbonate,
Examples thereof include benzoyl peroxide and azobisisobutyronitrile.

The basic compound can be selected from a wide range of organic basic compounds and inorganic basic compounds. Of the organic basic compounds, alkylamines such as triethylamine and alkylphosphines such as triethylphosphine are preferable. In inorganic basic compounds,
Preference is given to carbonates, hydroxides or oxides of alkali metals or alkaline earth metals such as potassium carbonate, potassium hydroxide, sodium hydroxide and magnesium oxide.

The amount of the polymerization initiator used can be appropriately changed depending on the type and the conditions of the copolymerization reaction, but usually about 0.05 to 0.5% by weight is adopted with respect to the total amount of the monomers to be copolymerized. To be done. The amount of the basic compound used is 0.01 to 20% by weight, preferably 0.1 to 20% by weight, based on the total amount of the monomers to be copolymerized.
About 10% by weight is adopted.

In the above-mentioned 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 operation and the separation of the produced copolymer can be adopted. For ease of use, emulsion polymerization in an aqueous medium or alcohols such as t-butanol, esters,
Solution polymerization using saturated halogenated hydrocarbons containing one or more fluorine atoms, aromatic hydrocarbons such as xylene, etc. as a solvent is preferable. The reaction temperature is about 10 ° C to 90 ° C, and the reaction pressure can be appropriately selected, but is usually 0 to 100 kg / cm · G, and particularly 1 to 50 kg / cm.
・ It is desirable to adopt G grade. The intrinsic viscosity of the produced copolymer is preferably 0.05 to 2.0 dl / g.

In order to control the intrinsic viscosity of the produced copolymer within the above range, a reaction medium having a relatively large chain transfer constant may be used, or the copolymerization reaction may be appropriately performed in the coexistence of a chain transfer agent. preferable.

[0021]

EXAMPLES Examples will be shown below to more specifically describe the present invention. In addition, the number of parts in the examples indicates parts by weight unless otherwise specified.

[Synthesis Example 1] Stainless steel autoclave with an internal volume of 200 cc and a stirrer (pressure resistance 50 kg / cm ² · G)
Chlorotrifluoroethylene (CTFE) 58 parts, cyclohexyl vinyl ether (CHVE) 19 parts, ethyl vinyl ether (EVE) 7.2 parts, ω-hydroxybutyl vinyl ether (HBVE) 12 parts, 10-undecenoic acid (UdA) 27 parts, 50 parts of isopropyl alcohol (IPA), azobisisobutyronitrile (AI
BN) 0.5 parts, anhydrous potassium carbonate 3.7 parts,
After cooling with liquid nitrogen and removing the dissolved air by solidification degassing, the reaction was carried out at 65 ° C. for 16 hours to obtain a carboxyl group-containing fluoropolymer.

The molecular weight of the obtained carboxyl group-containing fluoropolymer was measured by GPC. As a result, the number average in terms of polyester was M _n = 1.3 × 10 ⁴ , and the acid value was 69.
It was mgKOH / g-resin.

"Synthesis Examples 2-3" Polymerization was carried out in the same manner as in Synthesis Example 1 with the compositions shown in Synthesis Examples 2-3 of Table 1. The physical properties of the obtained fluoropolymer are shown in Table 1.

"Comparative Synthesis Examples 1-3" Comparative Synthesis Example 1 in Table 1
Polymerization was performed in the same manner as in Synthesis Examples 1 to 3 except that the basic compound was not added in the compositions shown in FIGS. The obtained results are shown in Table 1.

[Synthesis Examples 4 to 6] Polymerization was carried out in the same manner as in Synthesis Example 1 with the compositions shown in Synthesis Examples 4 to 6 in Table 2. The physical properties of the obtained polymer are shown in Table 2. AOPA is an abbreviation for allyloxypropionic acid.

"Comparative Synthesis Examples 4-5" Comparative Synthesis Example 4 in Table 2
Polymerization was carried out in the same manner as in Synthesis Examples 4 to 6 except that the basic compound was not added in the compositions shown in FIGS. The obtained results are shown in Table 2.

From Tables 1 and 2, carboxyl group-containing fluorocopolymers containing fluoroolefin, vinyl ether, hydroxy group-containing vinyl ether, and unsaturated carboxylic acid monomer having 5 or more carbon atoms as essential components are prepared. In this case, it can be seen that the polymerization does not proceed unless the basic compound is present in the polymerization system.

"Example 1" The solvent of the fluoropolymer resin B containing a carboxyl group obtained in Synthesis Example 2 was evaporated to isolate the polymer solid, which was then dissolved in IPA to obtain about 6 parts.
It was a 0 wt% IPA solution. Next, 80% of OH value
Was neutralized with triethylamine (TEA) to prepare a stock solution of the electrodeposition paint.

Melamine resin Cymel 303 (manufactured by Mitsui Cyanamid) was added to the undiluted solution of this electrodeposition paint at a ratio of 7: 3, and ion-exchanged water was added to prepare an aqueous dispersion type electrodeposition paint. When the solid content concentration of this water-based paint was measured, it was 10% by weight.

This paint was stored in an oven at 40 ° C. for 14 days, and the pH, electric conductivity and acid value of the aqueous paint were measured.
The results are shown in Table 3. Further, this water-based paint was applied to an aluminum plate (anode) which had been subjected to an alumite treatment by energizing at 180 V for 3 minutes. The obtained aluminum plate was washed with ion-exchanged water and then cured at 200 ° C. for 30 minutes, and the physical properties of the coating film were measured as shown below. The results are shown in Table 3.

Examples 2 to 3 Carboxyl group-containing fluoropolymer resins D and E obtained in the above synthesis examples were prepared in the same manner as in Example 1 to prepare an aqueous dispersion type electrodeposition coating composition having a solid content of 10% by weight. It was stored in an oven at 40 ° C for 14 days, and the pH, electric conductivity and acid value of the water-based paint were measured. The results are shown in Table 3. Similarly, the physical properties of the coating film applied to the aluminum plate were measured. The results are shown in Table 3.

Comparative Example 1 The fluoropolymer resin F containing a carboxyl group obtained in Synthesis Example 6 was adjusted to a solution of about 60% by weight in xylene and heated to 90 ° C. to obtain 3.6 parts with respect to 100 parts of the polymer. Succinic anhydride was added, and 0.2 part of triethylamine was further added, and the mixture was reacted for 2 hours.

When the infrared spectrum of the reaction solution was measured, the characteristic absorption of anhydrous acid (1850 cm ^-1 , 1780) observed before the reaction was observed.
cm ^-1 ) has disappeared after the reaction, and the carboxylic acid (17
10 cm ^-1) and absorption of ester (1735 cm ^-1) were observed.

Thus, the fluorine-containing polymer having a carboxyl group introduced therein has an acid value of 20 mgKOH / g-resin and a hydroxyl value of 1
It was 00 mgKOH / g-resin.

The obtained fluoropolymer was subjected to a new IP after the solvent was once evaporated and the solid content of the polymer was isolated.
The solution was dissolved in A to prepare an IPA solution of about 60% by weight to prepare a stock solution of an electrodeposition paint. Ion-exchanged water was added to the stock solution of this electrodeposition paint to prepare an aqueous dispersion type electrodeposition paint. When the solid content concentration of this water-based paint was measured, it was about 10% by weight.

This paint was stored in an oven at 40 ° C. for 14 days, and the pH, electric conductivity and acid value of the aqueous paint were measured.
The results are shown in Table 3. Further, this water-based paint was applied to an aluminum plate (anode) which had been subjected to an alumite treatment by energizing at 180 V for 3 minutes. The obtained aluminum plate was washed with ion-exchanged water and then cured at 200 ° C. for 30 minutes, and the physical properties of the coating film were measured as shown below. The results are shown in Table 3.

From Table 3, it can be seen that the fluoroolefin, vinyl ether, hydroxy group-containing vinyl ether, and unsaturated carboxylic acid having 5 or more carbon atoms are compared with the storage stability of the water-based paint acid-modified with succinic anhydride. Aqueous paint prepared from a carboxylic acid group-containing fluoropolymer having the monomer of as an essential component has good long-term storage stability,
It can be seen that a good coating film can be obtained even with the paint after long-term storage.

Examples 4 to 6 Further, the appearance and gloss retention of the coating films of Examples 1 to 3 were measured when the coating films were applied to a sunshine weather meter for 3000 hours. The results are shown in Table 4.

Comparative Example 2 The appearance and gloss retention of the coating film of Comparative Example 1 were measured when the coating film was applied to a sunshine weather meter for 3000 hours. The results are shown in Table 4.

Comparative Example 3 100 parts of ion-exchanged water was added to a commercially available acrylic-melamine-based electrodeposition coating clear stock solution (trade name: Electron AG100, manufactured by Kansai Paint Co., Ltd., resin solid content: 30% by weight) to obtain a resin solid content of 10% by weight. An aqueous dispersion type electrodeposition paint having a neutralization equivalent of 0.8 and an organic solvent of 5% by weight was prepared.

This water-based paint was applied to an aluminum plate (anode) which had been subjected to alumite treatment by energizing at 180 V for 3 minutes. The obtained aluminum plate was washed with ion-exchanged water and then cured at 200 ° C. for 30 minutes to give a coating film. The appearance and gloss retention of this coating film were measured with a sunshine weather meter for 3000 hours. The results are shown in Table 4.

The appearance of the coating film was visually observed and evaluated according to the following criteria according to the presence or absence of stains (◯: no stain,
Δ: Slightly stained, ×: Stained)

From Table 4, fluoroolefin, vinyl ether, hydroxy group-containing vinyl ether and carbon number 5
Aqueous paint prepared from a carboxylic acid group-containing fluoropolymer having the above unsaturated carboxylic acid monomer as an essential component,
It can be seen that the weather resistance of the coating film does not deteriorate even after coating after long-term storage.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

[Table 3]

[0048]

[Table 4]

[0049]

The paint prepared from the fluorine-containing copolymer of the present invention has good long-term storage stability, and a good coating film can be obtained even with the paint after long-term storage.

Claims (7)

[Claims] 1. A polymerized unit based on (a) a fluoroolefin, a polymerized unit based on (b) a vinyl ether containing no hydroxy group or a carboxyl group, (c) a polymerized unit based on a hydroxy group-containing vinyl ether, and (d). A carboxyl group-containing fluorocopolymer containing a polymerized unit based on an unsaturated carboxylic acid other than vinyl ethers having 5 or more carbon atoms and having a carboxyl group. 2. The copolymerization ratio of (a), (b), (c) and (d) is (b) 30 to 1 with respect to 100 mol of (a).
50 mol, (c) 3 to 100 mol and (d) 3 to 10
The fluorine-containing copolymer according to claim 1, which is 0 mol. 3. (a ′) Fluoroolefin, (b ′) hydroxy group- or vinyl group-free vinyl ether, (c ′) hydroxy group-containing vinyl ether, and (d ′) vinyl ether having 5 or more carbon atoms and carboxyl group. A method for producing a fluorinated copolymer containing a carboxyl group, which comprises copolymerizing an unsaturated carboxylic acid other than the above in the presence of a basic compound. 4. A copolymerization ratio of (a '), (b'), (c ') and (d') relative to 100 mol of (a '),
The production method according to claim 3, wherein (b ') is 30 to 150 mol, (c') is 3 to 100 mol, and (d ') is 3 to 100 mol. 5. The method according to claim 3, wherein the basic compound is an organic basic compound or an inorganic basic compound. 6. The method according to claim 5, wherein the organic basic compound is an alkylamine or an alkylphosphine. 7. The method according to claim 5, wherein the inorganic basic compound is an alkali metal or alkaline earth metal carbonate, hydroxide or oxide.