JPH07687B2 - Curable resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a curable resin composition.
In particular, the present invention is excellent in weather resistance, and by utilizing the property of a curable resin having a low surface energy, exhibits excellent effects in releasability and antifouling property, useful in the field of antifouling surface treatment, The present invention relates to a resin composition.

[Conventional technology and problems]

It is known to mix a curable silicone resin, mainly a rubber silicone resin, with a liquid having a releasing action such as silicone oil to form a coating having an antifouling effect particularly in seawater.

The same is said for thermoplastic type silicone resins. For example, JP-A No. 60-65076 discloses a reaction-curable silicone composition, JP-A No. 62-156172 discloses a polymer of vinyl silicon, and JP-A No. 62-275132 discloses a polysiloxane macromer. Copolymers with vinyl monomers are disclosed.

However, existing coatings based on these silicone resins are easily peeled off because of poor adhesion to the substrate under conditions of constant exposure to waves, such as when immersed in seawater. It is difficult to maintain the antifouling effect for a long period of time.

The present invention eliminates these conventional drawbacks, forms a low energy surface to exhibit an antifouling effect, has good adhesion to the substrate, and can withstand repeated stress such as waves sufficiently, and is practically used. The present invention relates to a coating composition that is difficult to peel off.

[Means for Solving the Problems]

That is, the present invention provides an antifouling coating composition containing the following components (A) and (B): (A) Having at least one active hydrogen in one molecule,
After the unsaturated isocyanate is reacted with the silicone resin whose main chain of the constituent molecule is a polysiloxane structure to convert it into a silicone resin having at least a portion having an unsaturated bond,
A graft polymer obtained by adding thereto a monomer having active hydrogen and a copolymerizable monomer as required, and (B) a polyvalent isocyanate compound.

That is, a silicone resin having a polysiloxane structure having active hydrogen is reacted with an unsaturated isocyanate to introduce an unsaturated bond into at least a part of the silicone resin, and then a monomer having active hydrogen and, if necessary,
To a graft polymer containing a silicone resin obtained by polymerization by adding a monomer copolymerizable with these,
By using a polyvalent isocyanate compound in combination, a curable resin composition that can obtain a coating film which is tough and has excellent durability and adhesion after coating and curing is obtained.

The final cured resin according to the present invention has a wide range of physical properties depending on (i) ratio of unsaturated silicone resin (ii) amount of monomer having active hydrogen (iii) type of monomer (iv) type and amount of polyvalent isocyanate, etc. Can be changed, and can be used for various purposes.

The curable resin composition according to the present invention has excellent adhesion to metals such as iron and aluminum, concrete, inorganic building materials such as slate, wood, etc., and by curing this, it is tough and durable. It becomes possible to obtain a certain coating film.

In order to facilitate the understanding of the present invention, (A) of the composition of the present invention
The procedure for making the components is illustrated below.

In the above formula, styrene is used as the vinyl monomer and 2-hydroxyethyl methacrylate is used as the monomer having active hydrogen.

The hydroxyl groups of the above graft copolymer are crosslinked with a polyvalent isocyanate.

The raw materials used for producing the component (A) of the composition of the present invention are classified into the following types.

(A) Silicone resin having active hydrogen, (b) unsaturated isocyanate, (c) monomer having active hydrogen, and optionally (d) a copolymerizable monomer.

The silicone resin (a) used for the production of the component (A) of the composition of the present invention has a main chain of constituent molecules represented by the following formula: (Wherein R and R'are alkyl groups and phenyl groups) and has a polysiloxane structure, and at least one active hydrogen capable of reacting with an isocyanate, typically a hydroxyl group, should be possessed in one molecule. is necessary.

As such a silicone resin, dimethylpolysiloxane having a hydroxyl group at the terminal is suitable, and examples of commercially available products include the following types manufactured by Shin-Etsu Chemical Co., Ltd.

The unsaturated isocyanate (b) for introducing an unsaturated bond into these hydroxyl group-containing silicone resins includes a) a compound which shares an unsaturated bond with an isocyanate group in one molecule, and b) a diisocyanate. With unsaturated monoalcohol
And 1 mole of adduct, and the like.

Examples of unsaturated isocyanates include, for example, isocyanate ethyl methacrylate, methacryloyl isocyanate, m-isopropenyl-α, α dimethylbenzyl isocyanate, generally isocyanate ethyl methacrylate (the following formula) Is preferable from the viewpoints of handleability and reactivity of isocyanate.

The reaction product of diisocyanate and unsaturated alcohol is, for example, an adduct of 2,4-tolylene diisocyanate and 2-hydroxyethyl methacrylate in an amount of 1 mol to 1 mol (the following formula).

In this case, diisocyanate includes 2,2-tolylene diisocyanate, isophorone diisocyanate, and the like.
Preference is given to different types of reactivity of the individual isocyanate groups.

The reaction ratio between the active hydrogen of the silicone resin and the unsaturated isocyanate is 0.01 part or more and 10 parts or less, preferably 0.1 part or more and 3 parts, with respect to 100 parts (weight part, the same below) of the silicone resin. It is the following. In this case, it is not necessary to react all the active hydrogen present. The degree depends on the types of monomers used together and the ratio of the unsaturated silicone resin to the monomers.

Examples of the monomer (c) having active hydrogen include 2-
Examples thereof include hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate and phenoxyethyl methacrylate.

The monomer used in combination as the copolymerizable monomer (d) may be any monomer as long as it can be copolymerized therewith, and generally commercially available types are used. There are no particular restrictions on the type,
Examples thereof include styrene, vinyltoluene, acrylic esters, methacrylic acid esters, acrylonitrile, methacrylonitrile, vinyl acetate, ethylene and butadiene.

The compounding ratio of the unsaturated bond-introduced silicone resin and the monomer can be freely changed, but the surface energy may increase depending on the amount and type of the monomer, and the antifouling effect and weather resistance may be insufficient.

If these are taken into consideration, the proportion of unsaturated bond-introduced silicone resin is 10 to 95% (wt%, the same applies hereinafter), preferably
20-80%.

The use ratio of the monomer (c) having active hydrogen is preferably about 1 to 30 mol% when the total amount of the monomer is 100, and the balance is a copolymerizable monomer (d).

Added to the graft polymer (A) having active hydrogen,
Examples of the polyvalent isocyanate compound (B) for reacting with this to cure the resin include the following types.

2,4-Tolylene diisocyanate, 2,6-Tolylene diisocyanate, Mixture of 2,4-Tolylene diisocyanate and 2,6-Tolylene diisocyanate, Diphenylmethane diisocyanate, Isophorone diisocyanate, Xylylene diisocyanate , Hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, 1,5 naphthylene diisocyanate, and polyisocyanates represented by the following general formula.

Adducts of these isocyanates with, for example, polyols, in which isocyanate groups remain, can be used as well.

Further, the combined use of a so-called urethane-forming catalyst in the reaction between the isocyanate compound and the active hydrogen of the polymer is effective in demonstrating the physical properties of the coating film at an early stage.

The mixing ratio of each component of the composition of the present invention varies depending on the purpose of use, but it is the unsaturated graft polymer which is the component (A).
The (B) polyvalent isocyanate compound is 0.1 per 100 parts by weight.
-30 parts by weight, preferably 1-15 parts by weight, more preferably 2-10 parts by weight.

In the resin composition according to the present invention, it is needless to say that a reinforcing material, a filler, a coloring agent, a wax and the like can be used in combination if necessary.

Next, the present invention will be further described with reference to examples.

Example 1 A stirrer, a reflux condenser, a thermometer, and a gas introduction were attached.
In a 2 liter separable flask, 200 parts of silicone resin having hydroxyl group (X-22-160B manufactured by Shin-Etsu Chemical Co., Ltd., hydroxyl value of about 35, molecular weight of 3200) (part by weight, the same applies hereinafter) and 0.8 of isocyanate ethyl methacrylate. Department,
Dibutyltin dilaurate (0.2 parts) was charged and reacted at 60 to 65 ° C for 4 hours. As a result of infrared analysis, it was confirmed that the free isocyanate group disappeared.

40 parts of 2-hydroxypropyl methacrylate,
Charge 177 parts of styrene, 300 parts of toluene, 4 parts of azobisisobutyronitrile, 2 parts of tert-butyldodecanethiol and add 2 parts of azobisisobutyronitrile on the way at 75-80 ° C for 16 hours. After polymerization, 0.1 part of hydroquinone monomethyl ether was added. A slightly viscous and cloudy solution of the homogeneous graft polymer of the component (A) was obtained.

To 100 parts of this solution of the component (A) polymer, 7 parts of isophorone diisocyanate as the component (B), 0.3 part of dibutyltin dilaurate, and 10 parts of toluene are mixed so that the thickness of the bonderite steel sheet becomes 100 μm. After coating, the mixture was left to stand overnight and then heated at 120 ° C. for 30 minutes to complete curing.

The hardness of the cured coating film was F, and no adhesion was found in the cellophane tape peeling test, and the peeling strength was 0.1 kg / in or less.

No peeling of the coating film was found in the coating film adhesion test by cross-cutting.

The gloss reflectance of the system to which 0.5 part of TINUVIN P (Ciba Co.) was added as an ultraviolet absorber was 90% at first and 85% after 1000 hours irradiation with a DEW cycle weatherometer, showing almost no decrease.

Comparative Example Similar to Example 1 except that a silicone resin having active hydrogen (manufactured by Shin-Etsu Chemical Co., Ltd.) X-22-160B was used as it is in place of the silicone resin to which isocyanate ethyl methacrylate was added. The reaction was carried out. The obtained polymer was separated into two layers after standing and did not become a uniform solution. That is, it is presumed that it was not grafted.

Example 2 A 2 l separable flask equipped with a stirrer, a reflux condenser, a thermometer, and a gas inlet tube was charged with a silicone resin having a hydroxyl group (Shin-Etsu Chemical Co., Ltd. X-22-160A, hydroxyl number 62, molecular weight 1800). 200 parts, 2.5 mol of an adduct of isophorone diisocyanate and 2-hydroxypropylmethacrylate as unsaturated isocyanate 1 mol to 1 mol
And 0.2 part of dibutyltin dilaurate were added, and the mixture was reacted at 65 to 70 ° C. for 3 hours. As a result of infrared analysis, it was confirmed that the free isocyanate group disappeared.

To this, 120 parts of methyl methacrylate, 84 parts of isobutyl methacrylate, 26 parts of 2-hydroxyethyl methacrylate
Part, azobisisobutyronitrile 2.5 parts, toluene 300
Part, 1.3 parts of lauryl mercaptan, and add at 65-70 ℃ for 15
After polymerization for a period of time, 0.1 part of hydroquinone was added to terminate the polymerization.

In this way, a cloudy, syrupy polymer as the component (A) was obtained.

To 100 parts of this component (A) polymer, 10 parts of toluene, 2,4-
4 parts of tolylene diisocyanate was added and coated on a Bonderite steel plate to a thickness of 100 μm. After standing overnight, heating was performed at 120 ° C. for 1 hour to complete curing.

The cured coating has gloss, hardness B, and there is no adhesive strength of the cellophane tape in the cellophane peeling test, and the peeling strength is 0.1k.
It was less than g / in. In the DEW cycle type weatherometer exposure test, the gloss reflectance before exposure was 89%, and after 1000 hours of exposure, it was slightly yellowing, but 86%, indicating almost no loss of gloss.

〔The invention's effect〕

Since the present invention is configured as described above, it is possible to provide a curable resin composition having good adhesion to a substrate and exhibiting excellent weather resistance and antifouling coating film performance.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-58-63717 (JP, A) JP-A-2-252721 (JP, A) JP-A-2-252773 (JP, A) JP-A-2- 252774 (JP, A)

Claims (1)

[Claims] 1. A curable resin composition containing the following components (A) and (B): (A) At least one active hydrogen atom in one molecule, and the main chain of the constituent molecules is polysiloxane. After reacting the structure of the silicone resin with an unsaturated isocyanate to convert it into a silicone resin having at least a portion having an unsaturated bond, a monomer having active hydrogen and optionally a copolymerizable monomer are added thereto. A graft polymer obtained by polymerization; and (B) a polyvalent isocyanate compound.