JPH04189880A - Resin composition for coating - Google Patents

Abstract

PURPOSE:To provide the subject composition containing a polymer having a specific fluorine-containing aliphatic ring structure and a solvent for dissolving the polymer as essential constituents and giving a coating film having excellent adhesivity to the surface of a substrate such as metal. CONSTITUTION:The objective composition contains an essential component produced by dissolving (A) a polymer having a fluorine-containing aliphatic ring structure having an acid value of >=0.01m-mol introduced by carboxylic acid group or sulfonic acid group per 1g of the polymer in (B) a solvent such as perfluorobenzene or trichlorotrifluoroethane. The component A is preferably a polymer having the ring structure on the main chain.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a coating resin composition containing a polymer having a fluorine-containing aliphatic ring structure as an essential component.

[Prior art] A polymer having a fluorine-containing aliphatic ring structure is disclosed in Japanese Patent Application Laid-Open No. 63
-238111, 238115 and U.S. Patent No. 47
As described in No. 54009, it is known that it is soluble in a specific solvent and can be coated, and that it has low crystallinity and thus provides a highly transparent coating film. Furthermore, coating films obtained from these polymers have the characteristics of fluororesins, such as low refractive index, low dielectric constant, low water absorption, and chemical resistance, so they are required to have these special physical properties. Suitable for various types of protective films.

However, the polymers described in these patents have a problem in that they have poor adhesion to various substrates and the coating film obtained by coating easily peels off.

It is possible to improve adhesion by using a brimer suitable for various substrates, or by treating the substrate with plasma, ozone, etc., but the treatment is complicated, and in this case, adhesion is not necessarily guaranteed. It wasn't good enough.

In addition, attempts have been made to introduce silanol groups into side chains in order to improve adhesion to substrates such as glass and quartz, but the introduction reaction is complicated and unreacted silane compounds remain. Therefore, there is a problem in that properties such as transparency and water resistance, which are characteristics of the fluororesin, are impaired.

[Problems to be Solved by the Invention] The present invention solves the drawbacks observed in coating compositions whose main components are a polymer having a fluorine-containing aliphatic ring structure as described above and a solvent that dissolves the polymer, and The object of the present invention is to provide a novel coating resin composition containing a polymer having a fluorine-containing aliphatic ring structure as a main component, which provides a coating film with excellent adhesion to materials.

[Means for Solving the Problems] Based on the recognition of the above-mentioned problems, the present inventors have made extensive studies and found that a polymer having a fluorine-containing aliphatic ring structure having a specific acid value has high adhesion to a substrate. It has been newly discovered that this material is extremely advantageous as a material for providing a coating film with properties.

The present invention was thus completed based on the above findings, and includes a polymer having a fluorine-containing aliphatic ring structure having an acid value of 0.01 mmol or more per gram and a solvent for dissolving the polymer as essential constituents. The present invention provides a novel coating resin composition characterized by the following characteristics.

In the present invention, the polymer having a fluorine-containing aliphatic ring structure may be exemplified over a wide range of examples, including those that are conventionally known or well-known. Therefore, in the present invention, a fluorine-containing polymer having the above-mentioned specific ring structure in the main chain is preferably employed.

For example, those having a ring structure as shown in the general formula (%) can be mentioned. Among these, polymers having the following ring structures are typical.

However, the content of the present invention is not limited to these only.

There are two methods for producing these polymers: However, it is not limited to these manufacturing methods.

1. By cyclization polymerization (1) CF-0-CF2CF2-0-CF2 in CF2
CF2↓ Radical polymerization (2) Ch=CF-CF2-CFCI-CF2-CF
=Ch↓ Radical polymerization (USP 3202643 etc.) (3) CF2=CF-0-CF2-CF=CF2↓
Radical polymerization U L: F2 2, using a cyclic monomer (USP 3978030) 10 CF2 = CF2 In the above, polymers having a perfluoroaliphatic ring structure were exemplified, but in the present invention, the above-mentioned fluorine Examples include those in which some of the atoms are substituted with other hydrogen atoms or organic groups, or those having a ring structure such as that obtained by metathesis polymerization.

Therefore, the polymer having a specific ring structure in the present invention can be obtained more smoothly and advantageously by the above-mentioned cyclopolymerization, but in particular, the polymer having two polymerizable groups with different polymerizability in the molecule and By using a monomer in which the linear part of the linking chain that connects these two polymerizable groups has 2 to 7 atoms, gelation can be achieved without using ultra-high pressure conditions or large dilution conditions. This allows the cyclization polymerization to proceed smoothly and advantageously while suppressing by-products.

First of all, it is desirable that the polymer suitable for the above-mentioned cyclopolymerization has two carbon-carbon multiple bonds having different polymerizability. Usually a carbon-carbon double bond is employed. For example, a fluorine-containing monomer with two non-symmetrical multiple bonds, a vinyl group and an allyl group, a vinyl ether group and a vinyl group, a fluorine-containing multiple bond and a hydrocarbon multiple bond, a perfluorinated multiple bond and a partially fluorinated multiple bond. Examples include: Secondly, it is desirable that the number of atoms in the straight portion of the connecting chain connecting these two carbon-carbon multiple bonds is 2 to 7. The number of atoms in the straight part of the connected chain is 0~
When the number is 1, cyclization polymerization is difficult to occur, and the same is true when the number is 8 or more. Generally preferred is a case where the number of atoms is 2 to 5.

In addition, the connecting chain is not limited to a straight line, and may have a side chain structure or a ring structure, and the constituent atoms are not limited to carbon atoms, but may also include heteroatoms such as O, S, and H. . Thirdly, it is desirable that the fluorine content be 10% by weight or more. If the fluorine content is too low, the specificity of the fluorine atom will be exhibited and it will be disgusting. Naturally, perfluoromonomers are preferably employed.

Specific examples of the above-mentioned specific fluorine-containing monomer include CF2
=CFOCF2CF=CF2. CF2=CFOCF2C
F2CF=CF2CF2=CFOCF2CFCF=CF
2, CF2=CFOCF20CF2CF=CF2CF
3 CF2=CFOCF2CF=CH2, CF2=CFOC
F2CF2CH=CH2゜CF2=CFOCF2 (C
H2), NHCC) I=CH2 (X is an integer from 0 to 3) CF3 CF2=CFCF2CF2CH=CH2,CF? =CF
CF2CFCH=CH2CF3 CF2=CHOC)12CH2CF=CF2, CH2
=CFCOCH2'C)(2cF=cF2CF3 CF(2=CFCOCH2CH2CF=CF2.

An example may be CH2=CHOCH2CH2CF2CF=CF2.

In the present invention, those having one vinyl ether group such as CF2''CFO- are preferably employed in terms of polymerization reactivity, cyclization polymerization, gelation suppression, etc. In particular, perfluoroallyl vinyl ether (CF2: CFOCF2CF
=CF2) and perfluorobutenyl vinyl ether (CF2=CFOCF2CF2CF=CF2).

The above-mentioned monomer components can be used alone or in combination of two or more, and there is no problem even if they are copolymerized in combination with other copolymer components to the extent that the essence of these components is not impaired. It's fleeting.

Other monomers to be copolymerized are not particularly limited as long as they have radical polymerizability, and include fluorine-containing monomers,
A wide range of hydrocarbons and others may be exemplified. Of course, these other monomers may be used alone in radical copolymerization with the monomer capable of introducing the specific ring structure, or two or more of these other monomers may be used in combination to carry out the above copolymerization reaction. You can let them do it. In the present invention, it is usually desirable to select fluorine-containing monomers such as fluoroolefins and fluorovinylethers as other monomers. For example, preferred examples include tetrafluoroethylene, perfluoromethyl vinyl ether, perfluoropropyl vinyl ether, and vinylidene fluoride, vinyl fluoride, chlorotrifluoroethylene, and the like.

As for the copolymer composition, in order to take advantage of the characteristics of the specific fluorine-containing aliphatic ring structure aimed at in the present invention, the composition of the cyclic structure is preferably 20% or more, and more preferably 4% or more.
It is desirable that it is 0% or more.

In the present invention, the fluorine-containing polymer may be crosslinked by any method if necessary.

As the crosslinking method, commonly used methods can be used as appropriate. For example, crosslinking can be achieved by copolymerizing a monomer having a crosslinking site, by adding a crosslinking agent, or by using radiation or the like.

As a method for making the above polymer contain a predetermined acid value,
A method in which polymerization is carried out in the presence of an initiator or chain transfer agent having a carboxylic acid group, sulfonic acid group, etc. or a precursor group thereof in the molecule, to introduce a polymer at the end of the polymer, and high temperature treatment in the presence of oxygen. A method of introducing acid groups by oxidatively decomposing the side chains of a polymer and then treating it with water, acrylic acid, methacrylic acid and derivatives thereof, methyl perfluoro(5-oxa-6-hebutenoate), perfluoro Copolymerize monomers containing carboxylic acids such as (3,5-dioxa-4-methyl-7-octensulfonyl) fluoride, sulfonic acids, or derivatives thereof, and add treatment such as hydrolysis as necessary. A method of introducing an acid group by introducing an amine group, an epoxy group, or other functional group into a polymer by various methods, and then reacting a site that is reactive with these functional groups with a substance having an acid group. For example, a method of introducing an acid group using

The acid value contained in the above polymer needs to be 0.01 mmol or more per gram of polymer. If it is less than this, sufficient adhesion to the substrate, which is the object of the present invention to be improved, cannot be obtained.

The molecular weight of the above polymer can be appropriately adjusted within a preferred range by methods such as reducing monomer wettability during polymerization, increasing the concentration of an initiator, and adding a chain transfer agent.

Furthermore, various additives such as antioxidants and ultraviolet stabilizers may be added to the fluorine-containing resin composition of the present invention in order to improve its practicality.

In the composition of the present invention, the solvent for dissolving the specific fluororesin is not limited as long as it dissolves the above polymer, but perfluorobenzene, "Afluid", etc.
(trade name: fluorinated solvent manufactured by Asahi Glass Co., Ltd.), "Florinert" (trade name: fluorinated liquid manufactured by 3M Company), trichlorotrifluoroethane, etc. are suitable. Naturally, two or more appropriate types can be used in combination as a solvent. Particularly in the case of mixed solvents, hydrocarbons, alcohols, and other organic solvents can also be used in combination. Solution temperature is 0.01
wt% to 50 wt%, preferably 0.1 wt% to 20 wt%
It is wt%.

For coating with the composition of the present invention, any conventional coating method can be employed, including brush coating, doctor blade coating, coating using a bar coater, spray coating, and spin cord. In particular, when smoothness is required, it is preferable to use a spin cord.

[Examples] Next, Examples of the present invention will be described in more detail, but it goes without saying that this description does not limit the present invention.

Synthesis Example 1 35 g of perfluoroallyl vinyl ether, 5 g of trichlorotrifluoroethane (hereinafter abbreviated as R113), 150 g of ion-exchanged water, 20 g of methanol, and 35 mg of (C3F7COO)2 as a polymerization initiator were mixed into a container with an internal volume of 200 m1. was placed in a pressure-resistant glass autoclave.

After purging the system with nitrogen three times, suspension polymerization was carried out at 26°C for 23 hours. As a result, 28 g of Polymer A was obtained.

When we measured the infrared absorption spectrum of this polymer, we found that
1660cm- due to the double bond present in the monomer
No absorption near 1,1840 cm-1 was observed.

In addition, this polymer was dissolved in perfluorobenzene and 19
When the NMR spectrum of F was measured, a spectrum showing the following repeating structure was obtained.

The intrinsic viscosity of this polymer [η is “′Florinat”]
FC-75 (Product name: Perfluoro (2) manufactured by 3M Company)
-butyltetrahydrofuran), hereinafter abbreviated as FC-75), was 0.30 at 30°C. The glass transition point of the polymer is 69°C, and it is a tough, transparent, glass-like polymer at room temperature. Moreover, the 10% thermal decomposition temperature was 462°C.

Synthesis Example 2 35g of perfluorobutenyl vinyl ether, R
113, 150 g of ion-exchanged water, 20 g of methanol, and 90 mg of diisopropyl peroxydicarbonate as a polymerization initiator were placed in a pressure-resistant glass autoclave having an internal volume of 200 m1.

After purging the system with nitrogen three times, suspension polymerization was carried out at 40°C for 23 hours. As a result, 28g of polymer B? ! Ta.

When we measured the infrared absorption spectrum of this polymer, we found that
1660cm- due to the double bond present in the monomer
+, there was no absorption near 1840 cm-+. Furthermore, when the NMR spectrum of 19F was measured, as in Synthesis Example 1, a spectrum corresponding to a ring structure was obtained.

The intrinsic viscosity of this polymer [η is 30°C in FC-75
It was 0.32. The glass transition point of the polymer is 11
0°C, and is a tough, transparent glass-like polymer at room temperature. Moreover, the 10% thermal decomposition temperature was 465°C.

The water absorption rate is 0.01% or less, and the dielectric constant at room temperature is 2.2 (6
0Hz~LM)Iz), and the volume resistance was 1017 or more.

Synthesis Examples 3 to 4 The fluorine-containing polymers obtained in Synthesis Examples 1 to 2 were
After heat treatment at 50°C for 8 hours, it was immersed in water to obtain fluorine-containing polymers C and D having acid values.

Table 1 shows the acid content determined from IR and NMR spectra.

Synthesis Example 5 27 g of perfluoroallyl vinyl ether, 3 g of methyl perfluoro(5-oxa-6-heptenoate), and 35 mg of (C3F?C00)2 as a polymerization initiator were placed in a pressure-resistant autoclave with an internal volume of 200 m1. After purging the system with nitrogen three times, it was heated to 23°C at 40°C.
Time suspension polymerization was performed. As a result, 11 g of Polymer E was obtained. The acid content determined from the IR and NMR spectra is
Shown in the table.

Synthesis Example 6 44 g of perfluorobutenyl vinyl ether, 3 g of methyl perfluoro(5-oxa-6-hebutenoate)
g, and 80 mg of diisopropyl peroxydicarbonate as a polymerization initiator were placed in a pressure-resistant autoclave having an internal volume of 200 m1. After replacing the system with nitrogen three times,
Polymerization was carried out at 40'C for 24 hours.

As a result, 21 g of Polymer G was obtained.

Synthesis Example 8 Polymers E and G obtained in Synthesis Examples 6 and 7 were hydrolyzed using sodium hydroxide to form polymers F and G, respectively.
Polymer H was obtained. Table 1 shows the acid content determined from IR and NMR spectra.

Synthesis Example 9 27 g of perfluoroallyl vinyl ether, 3 g of perfluoro(3,5-dioxa-4-methyl-7-octensulfonyl) fluoride, and 35 mg of (C3F7COO)2 as a polymerization initiator were added in an internal volume of 200 m
It was placed in a pressure-resistant autoclave. After purging the system with nitrogen three times, polymerization was carried out at 40°C for 23 hours.

As a result, 12 g of Polymer J was obtained. Table 1 shows the acid content determined from IR and NMR spectra.

Examples Polymers C, D obtained in Synthesis Examples 3 to 4 and 7.8,
Compositions 1 to 5 shown in Table 2 were obtained by dissolving F, H, and J in a fluorinated solvent (Florinat FC-43, manufactured by 3M).

Next, using these materials, spin cording was performed on various substrate plates at 200 rpm, and drying was performed at 80 to 180° C. for 1 hour. Next, a substrate was prepared according to JIS K5400, cellophane tape was applied, and then it was peeled off to evaluate adhesion. The results are shown in Tables 3 and 4.

A-E in the table corresponds to the number of board squares that remain intact, and is A when all the squares remain intact, and E when peeling is observed in all squares.

Comparative Example Compositions 6 to 9 were prepared and evaluated in the same manner as in the Examples using the polymers having no acid value obtained in Synthesis Examples 1 to 2 and 5.6. The results are shown in Tables 3 and 4.

[Effects of the Invention] In the composition of the present invention, the polymer having a fluorine-containing aliphatic ring structure has an appropriate acid value, so that metals,
It has the effect of providing a coating film with excellent adhesion to the surface of various base materials such as plastics.

Claims (1)

[Claims] 1. A resin composition for coating, comprising as essential components a polymer having a fluorine-containing aliphatic ring structure having an acid value of 0.01 mmol or more per gram and a solvent for dissolving the polymer. 2. The coating resin composition according to claim 1, wherein the acid value is provided by a carboxylic acid group or a sulfonic acid group. 3. The coating resin composition according to claim 1, wherein the polymer having a fluorine-containing aliphatic ring structure is a polymer having a ring structure in the main chain. 4. The coating resin composition according to claim 1, wherein the polymer having a fluorine-containing aliphatic ring structure is a polymer having a ring structure in the main chain obtained by cyclization polymerization.