JPH066658B2 - Curable resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a curable resin composition, and more particularly to a curable resin composition, which has durability including a specific fluororesin, a flexibility-imparting agent and a curing agent. The present invention relates to a curable resin composition having improved flexibility.

A curable resin composition comprising a fluororesin and a curing agent is known and is used as a material having excellent durability in the fields of paints, adhesives and the like. However, in the conventional composition, the obtained cured resin has insufficient elongation and flexibility,
For example, when coated on a metal plate such as a steel plate, an aluminum plate, a stainless plate, or a steel plate, the coating film cracks during bending, or when laminated on a plastic film with a large elongation, it follows the elongation of the base film. If it is not possible, cracks or peeling occurs, and when it is applied to a cement-based outer wall material such as mortar, the coating film is destroyed due to the cracking of the base material, the appearance is impaired, and moisture etc. There was a problem that it penetrates into the interior and induces deterioration of the substrate.

As a result of intensive studies, the inventors of the present invention have found that a composition comprising a specific fluororesin, a flexibility-imparting agent and a curing agent solves such a problem. I came to find something.

Thus, the present invention has been completed based on the above findings, and is a fluoroolefin-based fluororesin (A) soluble in a solvent having a hydroxyl group (however, 2, 2, 3, 3
-Excluding fluororesin in which tetrafluoropropyl vinyl ether is a comonomer), a flexibility-imparting agent (B) having a curing site, and further reacting with the hydroxyl group of (A) and the curing site of (B) A curable resin composition containing a possible curing agent (C) as an essential component and reacting these components in one shot, (A) in tetrahydrofuran at 30 ° C.
Has an intrinsic viscosity of 0.05 to 2.0 dl / g, (B) has a polymerized alkylene chain of an ethylenically unsaturated group, (B) has a molecular weight of 50 to 10,000, and a curing site is Number of hydroxyl groups and curing sites is 2-10 per molecule (meta)
Acrylic or unsaturated carboxylic acid copolymer, and characterized in that the blending amount of (B) and (C) per 5 parts by weight of (A) is 5 to 50 parts by weight and 1 to 100 parts by weight, respectively. The present invention provides a curable resin composition.

In the present invention, it is important to use a specific fluororesin. Fluororesin has a hydroxyl group and has an intrinsic viscosity of 0.05 to 30 measured at 30 ° C. in tetrahydrofuran.
It is 2.0 dl / g, preferably 0.07 to 1.0 dl / g, and is of a solvent-soluble type. With no hydroxyl group, the durability of the coating film is poor, and if the intrinsic viscosity is too low, the mechanical strength of the coating film will decrease, while if it is too high,
From the aspect of the viscosity of the composition, the solution concentration tends to be unavoidable, and the workability is impaired. Further, those which are insoluble in solvents cannot be applied because a uniform coating film is not formed.

In the present invention, as the fluororesin, it is possible to use a condensation polymerization system in addition to the addition polymerization system. As the addition polymer system, an addition polymer or addition copolymer of a fluorine-containing unsaturated compound, which contains a hydroxyl group, is adopted. Further, the fluororesin may be one having an epoxy group, a carboxyl group, an ester group, an unsaturated bond, active hydrogen, halogen and the like in addition to the hydroxyl group.

Examples of such fluororesins include fluoroolefin and hydrocarbon vinyl ethers, vinyl esters, α- and α-, in view of weather resistance of cured coating film, mechanical properties, and ease of manpower.
Addition-polymer-based ones such as fluoroolefin-based copolymers with olefins can be preferably used. In such a copolymer, hydroxyl group-containing vinyl ethers such as hydroxyalkyl vinyl ethers or vinyl ethers that can be hydrolyzed after polymer formation can be preferably used as the hydroxyl group-providing comonomer.

The copolymer as described above is subjected to a copolymerization reaction by allowing a polymerization initiator or a polymerization initiation source such as light or ionizing radiation to act on a mixture of monomers in a predetermined ratio in the presence or absence of a polymerization medium. It can be manufactured by tightening.

In the present invention, it is important to use a flexibility-imparting agent together with the fluororesin. The flexibility-imparting agent has a curing site, has an alkylene chain obtained by polymerizing an ethylenically unsaturated group in the molecule, and has a molecular weight of 50 to 10,000, preferably 100 to 30.
It is a copolymer of (meth) acrylate or unsaturated carboxylic acid having a number of cure sites of 2 to 10 per molecule. It is difficult to maintain long-term flexibility in the case of no curing site, and flexibility is low in the case of too low molecular weight, while workability is impaired in view of viscosity in the case of too high molecular weight. Further, if the number of curing sites is too large, sufficient flexibility cannot be obtained.

A hydroxyl group is adopted as the curing site in the flexibility-imparting agent in terms of flexibility and weather resistance of the cured coating film.

In the present invention, as a flexibility-imparting agent that can be preferably used, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hydroxyethyl acrylate,
Examples thereof include alkylene chain-containing polymers obtained by polymerizing ethylenically unsaturated groups such as copolymers of various (meth) acrylates such as glycidyl methacrylate or various unsaturated carboxylic acids such as acrylic acid and methacrylic acid.

In the present invention, a composition containing a fluororesin and a flexibility-imparting agent contains a curing agent such as a polyfunctional compound having reactivity with a hydroxyl group of the fluororesin and a curing site of the flexibility-imparting agent. Resin 100 parts by weight and flexibility-imparting agent 5
~ 50 parts by weight, preferably 1-100 for 8-30 parts by weight
It is mixed in a ratio of 3 parts by weight, preferably 3 to 50 parts by weight.
In addition to this, a curing aid or a curing catalyst can be appropriately added.

For example, when the composition is cured at room temperature with respect to the flexibility-imparting agent whose curing site is a hydroxyl group, diisocyanate or titanium alkoxide can be preferably used as the curing agent. When the composition is heat-curable, a melamine curing agent, a urea resin curing agent, a polybasic acid curing agent, etc., which are used in ordinary thermosetting acrylic paints, are effective as the curing agent. Here, examples of the melamine curing agent include butylated melamine, methylated melamine, and epoxy-modified melamine. Depending on the application, those having various degrees of modification of 0 to 6 can be used, and the self-condensation property can also be appropriately selected. You can Examples of the urea resin include methylated urea and butylated urea. As the polybasic acid curing agent, long-chain aliphatic dicarboxylic acids, aromatic polyvalent carboxylic acids or their anhydrides, blocked polyisocyanates, etc. are useful.

It is desirable to appropriately select such a curing system according to the type of base material and the working conditions. Galvanized steel sheet, for example
When factory construction is mainly carried out such as coating finish of inorganic board such as aluminum stainless steel, steel plate or asbestos slate, heat hardening type hardening system is preferably adopted. For on-site construction of objects and buildings, a room temperature curing type curing system is adopted.

In the present invention, it is important that the fluororesin, the flexibility-imparting agent and the curing agent are essential components and that these components are reacted in one shot. It is also possible to produce a prepolymer by reacting a fluororesin or a flexibility-imparting agent with a curing agent in advance, and obtain a cured coating film from the prepolymer and the remaining components. In that respect, there are cases where performance close to that of the present invention is achieved, but in that case, the viscosity of the composition increases, making construction difficult,
It becomes difficult to obtain a uniform coating film.

The curable resin composition of the present invention includes a colorant, a filler, an ultraviolet absorber, various stabilizers or thickeners, and leveling for the purpose of improving the distinctiveness, designability, adhesion, durability, etc., or forming a paint. It is also possible to properly mix agents and solvents.

The curable resin composition according to the present invention is excellent in flexibility in addition to weather resistance and durability, and is useful not only in paints but also in fields requiring flexibility such as adhesives and sealants, and particularly high layers. The utility value is extremely large as a paint for applications where complex repainting is difficult, such as construction and large structures.

Next, the present invention will be described more specifically with reference to Examples.

Example 1 The content molar ratio of chlorotrifluoroethylene, cyclohexyl vinyl ether, and hydroxybutyl vinyl ether was 50, 40, 10%, the water-dispersion group value was 50 mgKOH / g, and it was measured in tetrahydrofuran at 30 ° C. A fluororesin (A-1) having an intrinsic viscosity of 0.21 dl / g was used to prepare a composition having the composition shown below.

Fluororesin (A-1) 100 parts by weight Flexibility-imparting agent (B-1) 20 〃 Xylene / methyl isobutyl ketone 50/50 mixture 200 〃 In addition to the composition obtained above, an isocyanate curing agent (C-
1) 20 parts by weight was added and mixed uniformly, and then coated on a glass plate with an applicator. After being left at room temperature for 4 weeks, the coating film (thickness 40μ) was peeled from the glass plate and subjected to various tests described below (results are shown in Table 1). The coating film has excellent flexibility and high durability. It was confirmed to be a film.

[Coating film performance test] (1) Tensile test Tensileon (manufactured by Toyo Baldwin Co., Ltd.) was used to perform a tensile test at a tensile rate of 5 mm / min and temperature conditions of 25 ° C and -20 ° C to measure the elongation at break.

(2) Accelerated weather resistance test (according to JIS A 1415) Sunshine weather meter Black panel Temperature 63 ℃ Humidity 50% RH Water spray 12 hours continuous spray every 1 hour (B-1) Butyl acrylate / hydroxyethyl acrylate copolymer (Copolymerization molar ratio 90/10, molecular weight 3000) (C-1) Coronate EH (Japan Polyurethane Company) Comparative Example 1 Without using the flexibility-imparting agent (B-1), an isocyanate curing agent (C-1) was used. ) Was 18 parts by weight, a coating film was formed in the same manner as in Example 1, and the results of various performance tests are shown in Table 1.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C09J 127/12 PFJ 9166-4J // (C08L 27/12 33:00)

Claims (1)

[Claims] 1. A fluoroolefin-based fluororesin (A) soluble in a solvent having a hydroxyl group (however, 2, 2, 3,
3-Fluoropropyl vinyl ether is a comonomer except fluororesin), a flexibility-imparting agent (B) having a curing site, and a hydroxyl group of (A) and a curing site of (B). A curable resin composition containing a reactive curing agent (C) as an essential component and reacting these components in one shot, (A) in tetrahydrofuran at 30 ° C.
Has an intrinsic viscosity of 0.05 to 2.0 dl / g, (B) has a polymerized alkylene chain of an ethylenically unsaturated group, (B) has a molecular weight of 50 to 10,000, and a curing site is Number of hydroxyl groups and curing sites is 2-10 per molecule (meta)
Acrylic or unsaturated carboxylic acid copolymer, and characterized in that the blending amount of (B) and (C) per 5 parts by weight of (A) is 5 to 50 parts by weight and 1 to 100 parts by weight, respectively. Curable resin composition.