JPH01297410A - Fluorine-containing copolymer and production thereof - Google Patents

Abstract

PURPOSE:To obtain the subject copolymer useful for a sealant, etc., and capable of providing a cured material excellent in weather resistance and elasticity by copolymerizing a fluoroolefin and a monomer having plural ether linkages and copolymerizable therewith. CONSTITUTION:(A) A fluoroolefin (e.g., chlorotrifluoroethylene) and (B) 1-80 mol% monomer (e.g., condensate between hydroxybutyl vinyl ether and propylene oxide) copolymerizable therewith and having two or more ether linkages are copolymerized to provide an objective copolymer with 1000-50000 number-average molecular weight and containing 20-70mol% fluoroolefin-based polymerization unit and 1-80mol% other polymerization unit having a side chain with >=2 ether linkages, and containing >=30mol% total polymerization units of the components (A) and (B) based on the whole polymerization units.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a fluorine-containing copolymer and a method for producing the same.

[Conventional technology] Conventionally, in the field of sealants and coating materials,
There has been a need to develop a resin that has excellent elasticity and weather resistance, and can be cured at room temperature. In recent years, in addition to this, even if silicone resins satisfy the above conditions, there are problems of contamination due to migration of low molecular weight silicone oils and plasticizers contained therein, and problems with recoatability. Demand is also emerging.

For example, sealants have evolved from oil-based caulking materials with no elasticity to elastic urethane-based and polysulfide-based caulking materials, and silicone-based sealants with better weather resistance have been developed, but they are contaminated by low-molecular-weight silicone oil. It had the disadvantage of being extremely sensitive. Therefore, modified silicones have been developed in which the skeleton is made of polyalkylene oxide and has siloxane bonds only at the crosslinking sites, but this cannot be said to be a sufficient solution as there are cases where the weather resistance is insufficient.

On the other hand, fluoroolefin-vinyl ether copolymers are known as resins that have high weather resistance and room temperature curability, and are used as coating compositions and the like. Coating compositions made of such resins have excellent weather resistance, and are increasingly being recognized as beneficial to industry, such as increasing the durability of buildings.

However, as in the present invention, sealing materials, elastomers, waterproof materials that require higher elasticity as well as weather resistance,
Adhesives, I) Resins with even higher flexibility are desired for applications such as commercial paints and elastic paints.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and the present invention has been made in order to solve the above-mentioned problems.
70 mol%, polymerized qi position (2) containing a side chain having at least two ether bonds in a ratio of 1 to 80 mol%, and polymerized unit (1) and polymerized unit (
The object of the present invention is to provide a fluorine-containing copolymer characterized in that the total of 2) is contained in a proportion of 30 mol % or more, and the number average molecular weight is 1,000 to 50,000.

The fluorine-containing copolymer of the present invention is based on a fluoroolefin (containing 20 to 70 mol% of polymerized units). Examples of the fluoroolefin include tetrafluoroethylene and chlorotrifluoroethylene.

Trifluoroethylene, vinylidene fluoride.

Fluoroolefins having about 2 to 6 carbon atoms, particularly about 2 to 4 carbon atoms, such as vinyl fluoride, hexafluoropropylene, 7-bentafluoroethylene, etc., are preferably employed. Among these, barerolefins in which hydrogen is completely replaced with halogen are most preferred. Furthermore, if the amount of polymerized units based on fluoroolefins is less than 20 mol %, sufficient weather resistance may not be exhibited and staining may become noticeable during long-term use, which is not preferable. If the fluoroolefin content exceeds 70 mol%, it is not preferable because good elasticity or adhesion with other materials cannot be obtained. In particular, polymerizations based on fluoroolefins 1i
One containing 30 to 60 mol % of the 1° position is preferable.

In addition, the fluorine-containing copolymer of the present invention has a side chain having at least two ether bonds at the lii position from 1 to 8.
It is contained in a proportion of 0 mol%. Because it contains this specific side chain, it can become an elastic body with good elasticity. In particular, it is preferable that the end of this side chain is a curable site. It is thought that a cured product in which a cross-linkage is formed based on the curable site at the end of the side chain exhibits particularly excellent elasticity due to the specific cross-linkage structure.

The side chain having at least two ether bonds in the fluorine-containing copolymer of the present invention is a side chain consisting only of a needle bond and a carbon-carbon bond, such as a polypropylene glycol chain, a polyethylene glycol chain, or
It may also contain other bonds such as urethane bonds, ester bonds, and amino bonds. If the number of ether bonds in the side chain is less than 2, it is not possible to obtain a preferable elastic body, and thus it is not used. The greater the number of ether bonds in the side chain, the better the elasticity can be obtained, but if the length is too long, weather resistance and stain resistance will deteriorate, which is not preferable. Usually, the number of ether bonds is 40 or less, more preferably 30 or less. In addition, the ether bonds are usually composed of alkylene groups such as methylene, ethylene, propylene, and butylene groups, but those with a small number of carbon atoms between the ether bonds are highly hydrophilic, so fluorine-containing copolymers This is undesirable since the water resistance of the combined product or its crosslinked product may be reduced. Furthermore, those having a large number of carbon atoms between ether bonds have problems such as difficulty in synthesis, and are usually not preferably employed. Preferably an ethylene group. An alkylene group having about 2 to 6 carbon atoms such as a propylene group is employed. In this alkylene chain, some or all of the hydrogens bonded to carbon may be substituted with a substituent such as a halogen group such as fluorine or chlorine, an alkyl group, or an aryl group. In particular, in order to obtain a good elastic material, the number of ether bonds in the side chain must be 5 or more, and in order to obtain a product suitable for applications such as sealants, the number of ether bonds must be IO or more. Those are preferred. Moreover, as mentioned above, this specific side chain terminal is preferably a curable site. Such curable sites include hydroxyl groups,
Active hydrogen-containing groups such as amino groups, acid amide groups, mercapto groups, and epoxy groups.

Examples include active halogen-containing groups and hydrolyzable silyl groups.

Moreover, the polymerized unit containing this specific side chain is contained in a proportion of 1 to 80 mol%. If the content of polymerized units containing this specific side chain is too low, it is not preferable because a good elastic body may not be obtained or an elastic body may not be obtained. Also, if there is too much, weather resistance will deteriorate,
This is not preferable because it may become difficult to obtain an elastic body. In particular, a fluorine-containing copolymer containing 5 to 30 mol% of weight units containing a specific side chain is preferred.

Further, the fluorine-containing copolymer of the present invention may contain another polymerized unit in addition to the polymerization position 14 based on the fluoroolefin and the polymerization position 1114 containing a specific side chain. In this case, the polymerization li position based on the fluoroolefin and the polymerization iif at the polymerization position 1ii containing a specific side chain are contained in a proportion of 30 mol % or more -F based on the total polymerized units. These two types of polymerization! If the proportion of the r-position is too small, sufficient weather resistance, stain resistance and elasticity will not be exhibited. Another polymerization unit is a polymerization position based on the 111 type that can be copolymerized with a fluoroolefin, and a polymerization unit based on an ethylenically unsaturated compound such as a vinyl, allyl, acryloyl, or methacryloyl type. It will be done. It is preferable that these monomers are suitably copolymerized, so that many polymerized units are contained between polymerization intermediates having specific side chains, and elasticity is more effectively exhibited.

Moreover, such a fluorine-containing copolymer has a molecular weight of 50.00
It is preferable that it be about 0 or less.

If the molecular weight is too large, the coating workability will not be excellent when used as an elastic paint, which is not preferable. Particularly when used without a solvent, such as a sealant, those with a large molecular weight have extremely poor workability. When used without a solvent, it is preferable to use one with a molecular tH of 15,000 or less, particularly 10,000 or less. The lower limit of molecular weight is not particularly limited, but usually! , 000 or more, preferably 2.0
00 or more is accepted.

The fluorine-containing copolymer of the present invention can be prepared by the following method, etc.
can be manufactured.

First, is it a fluoroolefin that is copolymerizable with the fluoroolefin and has at least two ether bonds? A method of copolymerizing u-mers.

Second, polymerization based on fluoroolefins at position 11 (1)
20 to 70 mol%, polymerized unit (3) having a reactive group
The total amount of polymerized units (1) and (3) is 30% by mole based on the total polymerized units.
A method of reacting a fluorine-containing copolymer contained in the above ratio with a compound having at least one ether bond and capable of reacting with a reactive group of the fluorine-containing copolymer.

Thirdly, polymerization 1j1 position (+
1 to 20 to 70 mol%, polymerized units having hydroxyl groups (4
) in a proportion of 1 to 80 mol%, and in which the total of polymerized units (1) and polymerized units (4) is contained in a proportion of 30 mol% or more based on the total polymerized units, alkylene oxide An example is a method of causing an addition reaction.

In the first method, the monomer that can be copolymerized with a fluoroolefin and has at least two ether bonds is a polymer consisting of an ethylenically unsaturated group such as a vinyl group, an allyl group, an acryloyl group, or a methacryloyl group. Monomers with possible sites are employed. As such a simple compound, one having at least two ether bonds is employed. Such a monomer having an ether bond can be synthesized by the method shown below. Addition reaction of alkylene oxide to hydroxyl group-containing monomers such as hydroxyalkyl vinyl ether, hydroxyalkyl allyl ether, reaction product of acrylic acid and polyhydric alcohol, reaction product of glycidyl allyl ether and alkanolamine or phenolic compound, allyl alcohol etc. How to coerce. Hydroxyl group, alkoxysilyl group.

There is a method in which a qt-mer having a reactive group such as an epoxy group or an amino group is reacted with a polyether compound having a group capable of reacting with the above-mentioned reactive group such as an isocyanate group, an alkoxysilyl group, or a carboxylic acid group. I can give an example. In addition, in this first method, when one type each of a fluoroolefin and a monomer having at least two ether bonds are polymerized, there is a high possibility that alternating copolymerization will occur. This possibility becomes extremely high when the monomer is a vinyl or allyl compound. In the case of alternate copolymerization, the number of other polymerized units existing between polymerized units having at least two ether bonds is about one, making it difficult for the polymer to exhibit good flexibility or elasticity. Preferably, one or both of the fluoroolefin and the monomer having at least two ether bonds contain two different types.
Employing more than one compound. Alternatively, at least two ether bonds in the pentapolymer can be obtained by copolymerizing a fluoroolefin, a monomer having at least two ether bonds, and a comonomer that can be copolymerized with these. It is operated so that a large number of other polymerized units exist between the polymerized units having . Usually, the latter method of copolymerizing comonomers is employed. Here, as the comonomer, a compound having a polymerizable moiety such as a vinyl group, allyl group, acryloyl group, or methacryloyl group is employed. Specifically, olefins, vinyl ethers, and vinyl esters.

Examples include allyl ethers, allyl esters, acrylic esters, and methacrylic esters.

Particularly preferred are compounds having a linear bibranched or alicyclic alkyl group having about 1 to 15 carbon atoms. As such a comonomer, one in which part or all of the hydrogen bonded to carbon is replaced with fluorine may be employed. In addition, in this first method, the polymerization ratio of each polymerizable monomer is 20 to 70 mol% of fluoroolefins, 1 to 80 mol% of monomers having at least two ether bonds, and It has at least two fluoroolefins and ether bonds per polymerized unit! It is preferable to control the copolymerization so that the ij D form is copolymerized in a proportion of 30 mol% or more. Such polymerization may be carried out by any method such as solution polymerization, emulsion polymerization, suspension polymerization, or bulk polymerization. It is done. In addition, other conditions can be the same as those normally used for solution polymerization, emulsion polymerization, suspension polymerization, bulk polymerization, etc.

In the second method, the fluorine-containing copolymer is prepared by copolymerizing a fluoroolefin, a monomer containing a reactive group or a group that can be converted into a reactive group, and optionally other comonomers. Can be synthesized. Reactive groups include hydroxyl group, carboxylic acid group, amino group, mercapto group,
Examples include active hydrogen-containing groups such as acid amide groups, epoxy groups, unsaturated groups, hydrolyzable silyl groups, and active halogen-containing groups. Here, as the reactive group-containing monomer, hydroxyalkyl vinyl ether 9 hydroxyalkyl allyl ether, hydroxyalkyl vinyl ester, hydroxyalkyl allyl ester, glycidyl vinyl ether, glycidyl allyl ether, aminoalkyl vinyl ether, aminoalkyl allyl ether, aminoalkyl Vinyl ester, aminoalkyl allyl ether.

Examples include acrylic acid, methacrylic acid, and allyl vinyl ether. Examples of groups that can be converted into monoreactive groups include ester groups that can be hydrolyzed after polymerization. Further, the reactive group may be converted to another reactive group after polymerization, if necessary. For example, reacting a hydroxyl group with a polyhydric carboxylic acid or its anhydride to convert it into a carboxylic acid group, reacting a hydroxyl group with a silyl isocyanate,
Converts to hydrolyzable silyl group. Examples include a method in which an epoxy group is reacted with an alkanolamine or a phenolic compound to convert it into a hydroxyl group, and a method in which a hydroxyl group is reacted with isocyanatoalkyl methacrylic acid to be converted into an unsaturated group. Furthermore, in synthesizing the fluorine-containing copolymer, monomers similar to those described in the first method may be copolymerized. In addition, the fluorine-containing copolymer has 20 to 20 to 10 polymerized units (1) based on fluoroolefin.
70 mol% 9 polymerized units (3) having reactive groups from 1 to 8
The total amount of polymerized units (1) and (3) is 30 mol% or more based on all polymerized units. In fluorine-containing copolymers,
If each polymerization unit is not contained in the above ratio, it will be difficult to produce the desired fluorine-containing copolymer.

In the second method, the fluorine-containing copolymer is reacted with a compound having at least one ether bond and a group capable of reacting with the reactive group of the fluorine-containing copolymer. According to this second method, a fluorine-containing copolymer having an ether bond in the side chain can be produced. In particular, when the polymerized unit having a reactive group of the fluorine-containing copolymer contains an ether bond such as vinyl ether or allyl ether, or when the ether bond is formed by a reaction between the fluorine-containing copolymer and a compound having an ether bond. If the compound to be reacted has one ether bond,
Even if the compound has two ether bonds, it is possible to obtain a fluorine-containing copolymer having a polymerized C unit including a side chain having two ether bonds (that is, the fluorine-containing copolymer of the present invention). In addition, when the polymerized unit having a reactive group does not have an ether bond or when an ether bond is not generated by the reaction, the compound to be reacted may be a compound having at least two ether bonds. A fluorine-containing copolymer having a polymerized unit containing a side chain having at least two ether bonds according to the present invention can be produced. The compound to be reacted is preferably a compound having 5 or more ether bonds, particularly a compound having 0 or more ether bonds. Furthermore, the group capable of reacting with the reactive group of the fluorine-containing copolymer can be appropriately selected depending on the type of the reactive group of the fluorine-containing copolymer. Specific examples include isocyanate groups, hydroxyl groups, carboxylic acid groups, epoxy groups, amino groups, and hydrolyzable silyl groups. Such compounds are usually prepared by addition polymerizing alkylene oxide L7 according to a conventional method, and then reacting the terminal hydroxyl group with silyl isocyanate, polyhydric carboxylic acid, or its anhydride, etc., as necessary. can be synthesized by the method. The reaction between a fluorine-containing copolymer and a compound having at least one ether bond and a group capable of reacting with the reactive group of the fluorine-containing copolymer is as follows:
It is desirable to react under conditions in which more than one compound is reacted per reactive group of the fluorine-containing copolymer. If the amount of the compound to be reacted is small, a crosslinked structure may be formed between the fluorine-containing polymers, which may complicate subsequent handling, which is not preferable.

Examples of compounds having at least one ether bond and a group capable of reacting with the reactive group of the fluorine-containing copolymer include vinyl ethers, allyl ethers, alkylene oxide addition polymers, and alkylene oxide addition polymers. , alkanolamines, polyvalent isocyanate compounds, isocyanate alkyl acrylates, silyl isocyanates, polyvalent carboxylic acid anhydrides, and the like.

The third method uses polymerized units based on fluoroolefins (
1) by 20 to 70 mol%, polymerized units having hydroxyl groups (4
) Alkylene oxide is added to a fluorine-based copolymer containing 1 to 80 mol% of the total polymerized unit (1) and polymerized unit (4) of 30 mol% or more of the total polymerized units. This method involves an addition reaction.

Here, the fluorine-based copolymer can be manufactured by the same method as explained in the second method above. However, the fluorine-based copolymer must have a hydroxyl group for use in vehicle equipment. Hydroxyalkyl vinyl ether, hydroxyalkyl allyl ether9. When a hydroxyl group-containing monomer such as allyl alcohol is copolymerized, the hydroxyl group can be easily introduced into the fluorine-based copolymer. On the other hand, when a monomer having reactivity other than hydroxyl groups, such as glycidyl allyl ether or acrylic acid, is copolymerized, it is necessary to convert the reactive groups to hydroxyl groups. Conversion of a reactive group into a hydroxyl group can be easily achieved by reacting a compound such as an alkanolamine or a polyhydric alcohol. This addition reaction of the fluorine thread copolymer hair alkylene oxide can be carried out in the same manner as in the production of ordinary diriether compounds. In addition, in this third method, after performing the addition reaction of alkylene oxide, the hydroxyl group generated at the end of the side chain is replaced with another reactive group, such as a carboxylic acid group.
It may also be converted into a hydrolyzable silyl group or the like.

The fluorine-containing copolymer of the present invention, particularly the composition consisting of a fluorine-containing copolymer having a curable site at the end of a specific side chain and a curing agent, provides a cured product with good elasticity, so it can be used as a sealant, It can be preferably used as a base for elastic paints, etc. Here, the curing agent includes a compound that reacts with the curable site of the fluorine-containing copolymer to form a cross-linking bond, a compound that promotes a reaction between the curable sites of the fluorine-containing copolymer, etc. It will be done. Among these, polyol-modified isocyanate compounds are preferred because they provide cured products with good elasticity. Here, if the curing reactive site of the fluorine-containing copolymer is a hydrolyzable silyl group or the cured product is a polyvalent isocyanate compound, it can be cured with moisture and has excellent workability. preferable. When a polyvalent isocyanate compound is employed as a curing agent, active hydrogen-containing groups, particularly hydroxyl groups, are preferable as the curable site of the fluorine-containing copolymer because of their excellent reactivity.

In addition to the above two components, such a composition also contains a filler, a solvent, a light stabilizer, and an ultraviolet absorber.

A heat stabilizer, a leveling agent, etc. may be added and blended.

Fillers include reinforcing fillers such as silica, precipitated silica, anhydrous silicic acid, hydrated silicic acid and carbon black: calcium carbonate, magnesium carbonate, diatomaceous, calcined clay, clay, talc, titanium oxide, bentonite, organic bentonite, ferric oxide, zinc oxide,
Fillers such as activated zinc white, hydrogenated castor oil and shirasu balloons; fibrous fillers such as asbestos, glass fibers and filaments can be used.

If you want to obtain a hardened composition with high strength using these fillers, you can use mainly silica, precipitated silica, anhydrous silicic acid, hydrated silicic acid, carbon black, surface-treated fine calcium carbonate, calcined clay, clay, Preferable results can be obtained if the filler selected from active zinc white and the like is used in an amount of 1 to 100 parts by weight per 100 parts of the fluorine-containing copolymer. In addition, if you want to obtain a hardened composition with low strength and high elongation, you can use titanium oxide, calcium carbonate, magnesium carbonate, talc, ferric oxide, zinc oxide,
Preferable results can be obtained by using a filler selected from fillers such as and shirasu balloons in an amount of 5 to 20 parts by weight based on 100 parts by weight of the fluorine-containing copolymer. Of course, these fillers may be used alone or in a mixture of two or more.

[Example] Synthesis Examples 1 to 3 Hydroxybutyl vinyl ether (H
BVE), potassium hydroxide (concentration 95%) at 5℃
into a pressure-resistant reactor equipped with a stainless steel stirrer, and gradually added propylene oxide (PO) at a rate of 3 kg/cm.
", I The reaction was carried out at 10°C for a predetermined time. The obtained liquid was purified with synthetic magnesia to obtain a vinyl ether having a polyoxyalkylene chain. The number of moles of PO added to each vinyl ether is shown in Table 1. Ta.

Table 1 Examples 1 to 5. Ratio Example 1, 2 In a stainless steel pressure-resistant reactor with an internal volume of 550 mQ and equipped with a stirrer, 112 g of xylene, 2 g of ethanol, 1.6 g of potassium carbonate, and 0.5 g of azoisobutyronitrile are placed.
The monomers having the composition shown in Table 2 were polymerized. Polymerization is carried out by charging monomers other than chlorotrifluoroethylene (CTFE) or tetrafluoroethylene (TFE), removing residual air with liquid nitrogen, then introducing CTFE or TFE, and gradually raising the temperature to ambient temperature. The temperature was maintained at 65°C, and the polymerization reaction was continued for 10 hours with stirring, and then the reactor was cooled with water to stop the polymerization. After the reactor was cooled to room temperature, unreacted monomers were extracted and the reactor was opened. After filtering the polymer solution, the solvent was removed using an evaporator to obtain a fluorine-containing copolymer.

The hydroxyl value (KOII mg) of the obtained fluorine-containing copolymer
/g), for number average molecules, and the glass transition temperature are shown in Table 2.

In addition, in the molecular weight measurement of the fluorine-containing copolymer (G, P, C, used) in each example, almost no peak was observed in the portion corresponding to the vinyl ether obtained in Synthesis Example 1.2.3. It is presumed that vinyl ethers having polyoxypropylene chains are copolymerized.

In Table 2, CTFE stands for chlorotrifluoroethylene, T
FE is detrafluoroethylene.

EVE represents ethyl vinyl ether, CI (VE represents cyclohexyl vinyl ether, and HBVE represents hydroxybutyl vinyl ether).

Example 6 145 g of xylene and 145 g of ethanol were placed in a pressure-resistant reactor made of stainless steel with an internal capacity of 550 mf2 and equipped with a stirrer.

EVE (ethyl vinyl ether) 33 g.

HBVE (Hydroxybutyl vinyl ether) 5.5
g, potassium carbonate Ig, and 0.5 g of AIBN (azoisobutyronitrile) were charged, and dissolved air was removed by solidification and degassing with liquid nitrogen. Thereafter, 58 g of CTFE (chlorotrifluoroethylene) was introduced and the temperature was gradually raised. The reaction was continued under stirring while maintaining the temperature at 65°C, and after 10 hours, the reaction vessel was cooled with water to stop the reaction. After cooling to room temperature, unreacted monomers are extracted and the reactor is opened. After filtering the reaction solution, the solvent was removed using an evaporator to obtain a fluorine-containing copolymer.

Furthermore, +000 g of this fluorine-containing copolymer was placed in a pressure-resistant reactor equipped with a stainless steel stirrer and having an internal capacity of 5Q.

Charge 6 g of 95% potassium hydroxide, and gradually add 816 g of PO (propylene oxide). 3 kg/cm'', 10 hours at 110°C, and the resulting transparent multicolored liquid was purified with synthetic magnesia to obtain the desired fluoroolefin copolymer having an added mole of PO of 20 moles. The hydroxyl value of the obtained resin was 15 (Oll mg/g), GP
The number average molecular weight according to C is 10.000. The glass transition temperature was -25°C.

Example 7 100 g of polyoxypropylene diol with a molecular ffi of 1.000 and 15 g of dimethylsilyl diisocyanate
g were mixed and reacted to obtain polyoxypropylene having terminal isocyanate groups. 100 g of the fluorine-containing copolymer obtained in Comparative Example 1 was reacted with 30 g of this polyoxypropylene having terminal isocyanate groups to obtain a fluorine-containing copolymer having a polyoxyalkylene chain.

Application examples 1 to 6. Application comparative example 1.2゜Examples 1 to 6. NGO1011 = a polyol-modified diisocyanate compound (trade name DEURAARD D101, manufactured by Asahi Kasei) was added to the fluorine-containing copolymer obtained in Comparative Example 1.2.
1, and 500 ppm of dibutyltin dilaurate as a catalyst was added for curing. Table 3 shows the test results for elongation at break, strength at break, modulus of elasticity, surface tackiness, and weather resistance of the cured tube.

Application example 7 The fluorine-containing copolymer obtained in Example 7 was moisture cured.

Table 3 shows the test results for elongation at break, strength at break, modulus of elasticity, surface tackiness, and weather resistance of the cured product.

Comparative Application Example 3 Polyoxypropylene triol with a molecular fi of 5,000 (hydroxyl value 33.7 K) was used instead of the fluorine-containing copolymer.
A cured product was obtained in the same manner as in Application Example 1 except that OII mg/g l was used. Table 3 shows the test results for elongation at break, strength at break, modulus of elasticity, surface tackiness, and weather resistance of this cured product.

Application Comparative Example 4 Same as Example 1 except that instead of the fluorine-containing copolymer, a fluorine-containing copolymer to which 3 moles of ε-caprolactone were added per 1 mole of hydroxyl group of the fluorine-containing copolymer of Comparative Example 1 was used. A cured product was obtained. The results of each test of this cured product are
Shown in the table.

Application Comparative Example 5 Commercially available modified silicone sealing materials were tested for elongation at break, strength at break, modulus of elasticity, surface tack, and weather resistance, and the results are shown in Table 3.

In each application example and application comparative example, elongation at break, strength at break 2 modulus of elasticity were determined in accordance with JIS K-6301,
The surface tackiness was measured using Victamac (manufactured by Toyo Seiki) under a load of 100 g. Weather resistance is the surface condition after 1000 hours on the Sunshine Weather-O-meter (0 = no change, ◯ = slight decrease in cross-resistance, but no other problems).

× indicates significant surface deterioration), and elongation retention (elongation at break after weathering test/initial elongation at break x IO (%)) was evaluated.

[Effects of the Invention] The fluorine-containing copolymer of the present invention provides a cured product with excellent weather resistance and excellent elongation, and is therefore extremely useful as a base for sealants and elastic paints.

Claims (1)

[Claims] 1. 20 polymerized units (1) based on fluoroolefins
~70 mol%, polymerized unit (2) containing a side chain having at least two ether bonds in a ratio of 1 to 80 mol%, and polymerized unit (1) and polymerized unit (
A fluorine-containing copolymer containing the sum of 2) in a proportion of 30 mol % or more and having a number average molecular weight of 1,000 to 50,000. 2. The method for producing a fluorine-containing copolymer according to claim 1, characterized in that a fluoroolefin and a monomer copolymerizable with the fluoroolefin and having at least two ether bonds are copolymerized. 3. 20 polymerized units (1) based on fluoroolefin
~70 mol%, 1 to 70 mol% of polymerized units (3) having reactive groups
A fluorine-containing copolymer containing a proportion of 80 mol% and a total of polymerized units (1) and polymerized units (3) of 30 mol% or more relative to all polymerized units, and at least one ether bond. 1. A method for producing a fluorine-containing copolymer, which comprises reacting a reactive group of the fluorine-containing copolymer with a compound capable of reacting. 4. 20 polymerized units (1) based on fluoroolefins
~70 mol%, 1 to 8 polymerized units (4) having hydroxyl groups
Addition reaction of alkylene oxide to a fluorine-based copolymer containing 0 mol% and containing the total of polymerized units (1) and polymerized units (4) in a proportion of 30 mol% or more based on the total weight unit. 1. A method for producing a fluorine-containing copolymer. 5. 20 polymerized units (1) based on fluoroolefin
~70%, polymerized unit (5) containing at least two ether bonds and a side chain whose terminal is a curable site at a ratio of 1 to 80 mol%, and the polymerized unit (1
) and polymerized units (5) in a total proportion of 30 mol % or more, and a fluorine-containing copolymer and a curing agent. 6. The curable composition according to claim 5, wherein the curing agent is a diisocyanate compound.