JPS6092367A - Self-polishing paint - Google Patents

Abstract

PURPOSE:To provide the titled paint which does not cause thickening nor gelation during storage, does not have lot-to-lot variability in the quality of the same blend and is useful as an antifouling paint, by using a specified itaconate polymer as a vehicle. CONSTITUTION:20-100wt% itaconate of the formula (wherein R1, R2 are each a 1-8C alkyl) and 80-0wt% unsaturated monomer [e.g. methyl (meth)acrylate] copolymerizable therewith are (co)polymerized to obtain an itaconate polymer. A vehicle composed of said polymer or obtd. by adding not more than 20wt% (meth)acrylate such as 2-hydroxymethyl (meth)acrylate to the polymer is dissolved in an org. solvent to obtain varnish. An antifouling agent (e.g. cuprous oxide), germicide, etc. are blended with the varnish to form a paint.

Description

[Detailed description of the invention] The present invention relates to a new self-polishing paint.

A typical self-polishing paint is a self-polishing ship bottom antifouling paint, which has a relatively uneven paint surface that is gradually disturbed by seawater during ship operation and becomes a smooth surface, making it difficult to handle underwater. There is a 71J effect that significantly reduces frictional resistance and saves fuel consumption. In fields other than ship bottom paint, the paint film is water! Of course, there are uses for self-polishing paints that gradually melt on contact and always expose a new coating surface, but for the sake of convenience, the following will be explained using a ship bottom antifouling paint as an example.

Self-polishing paints known so far use acrylic resin (trialkyltin polymer compound) with organic tin introduced into the resin as a hydrolyzable resin vehicle.
is used as a vehicle. The antifouling paint using this trialkyltin polymer compound as a vehicle is
As mentioned above, it is attracting attention not only because it reduces underwater frictional resistance during ship operation and helps save fuel consumption, but also because it exhibits the desired antifouling performance over a long period of time.

This is because the trialkyltin polymer compound resin gradually undergoes hydrolysis and elutes into seawater, and at the same time, the antifouling agent also elutes at a constant rate in proportion to the degree of elution of the resin. This is because the antifouling period can be extended proportionately. Also, unlike conventional rosin-based chlorinated rubber-based and vinyl-based antifouling paints, this antifouling paint dissolves the paint film and eliminates the old paint film, so it can be repainted with simple surface preparation. It also helps reduce painting work costs.

However, from ``bacterial, environmental and public health'' considerations, self-polishing paint vehicles that reduce or eliminate the use of organotins are attracting attention. For example, JP-A-55-36230 proposes the use of polymers or copolymers of dialkyl maleates or dialkyl fumarates as vehicles. However, maleic acid dialkyl esters and fumaric acid dialkyl esters generally have extremely poor homopolymerizability and copolymerizability with acrylic fl''-mers, and only a small amount is introduced into the resin, with most of them remaining unreacted (as 11-mers). When these varnishes are used in paints, they tend to thicken and gel during storage, and due to their low copolymerizability, it is difficult to mix the resin composition as designed (7). It was found that it was difficult to control the elution rate of the coating film, and the dispersion between lots was large, making it difficult to control the elution rate of the coating film.

The present invention provides a self-polishing paint that does not have such drawbacks and uses a slightly water-soluble resin that does not contain organic tin.

According to the present invention, a polymer of itaconic acid ester of the general formula: A self-polishing paint is provided which contains a copolymer with an unsaturated monomer as a vehicle.

According to the present invention, since the itaconic acid dialkyl ester of formula (a) has low copolymerizability with other ftoJ forms, traces of unreacted itaconic acid dialkyl ester fl' remain in the final resin solution. Therefore, during storage of the paint, there will be no thickening or gelling phenomenon, and for the same reason, the resin composition can be obtained as designed, so there will be no variation between 071 and 071 in the same formulation, and it will be stable. A coating film of the same quality can be supplied.

Furthermore, when used as an antifouling paint, since the resin vehicle has slight water solubility, the coating film gradually dissolves into seawater, and as a result, a certain concentration of antifouling agent is stably eluted, which is proportional to the film thickness. As a result, it has become possible to exhibit a constant antifouling effect for a long period of time. Furthermore, since the resin does not contain organic tin, it is safe for the environment and public health.

The object of the present invention can be fully achieved by using a homopolymer of itaconic acid dialkyl ester of the formula +a+ as a vehicle, but in order to impart toughness to the coating film or to control the dissolution rate of the coating film, It is also possible to form a copolymer of the itaconic acid dialkyl ester of the formula fa+ with other monomers, and in order to impart even more slight water solubility, it is possible to form a copolymer with a hydroxyl group-containing (meth)acrylic ester. Polymers can also be used.

Group R1゜R of itaconic acid dialkyl ester of formula fat
2 is suitably an alkyl having 1 to 8 carbon atoms;
Polymers or copolymers using itaconic acid dialkyl esters of the Zuro formula (11) having an alkyl group of C0 or more have poor water solubility, no elution of the coating film is observed, and are antifouling agents with long-term antifouling properties. They are unsuitable as paint vehicles; methyl, ethyl, propyl and butyl esters are therefore preferred.

Examples of unsaturated monomers copolymerizable with the itaconic acid dialkyl ester represented by formula (a) include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, and (meth)acrylate. In addition to (meth)acrylic acid esters such as isobutyl acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isopropyl (meth)acrylate, and n-hexyl (meth)acrylate, Allylamide, acrylonitrile, vinyl acetate, vinyl ethyl ether, styrene, α-
Common unsaturated monomers such as methylstyrene and vinyltoluene can be used. In a copolymer with these monomers, it is generally preferable to contain at least 20% by weight of ichconic acid dialkyl ester of the formula (al). No elution is observed.

Human t-xyl group-containing (meth)acrylic acid esters used for the purpose of imparting slight water solubility include 2-hydroxyethyl (meth)acrylate, 2-(meth)acrylate
Examples include humanoidipropyl.

If these hydroxyl group-containing (meth)acrylic acid esters are used in excess, the resin becomes hydrophilic and the coating film swells in seawater, making it impossible to obtain a strong coating film.
Hereinafter, it is preferably used in an amount of 7% by weight or less. Acrylic acid or methacrylic acid may also be used in some cases.

The resin containing dialkyl itaconic acid used as a vehicle in the present invention does not itself have antifouling properties, so when used as a vehicle resin for antifouling paint,
Copper compounds such as cuprous oxide, copper rhodanide, bis(tributyltin) oxide, tributyltin chlorand, tributyltin fluoride, tributyltin acetate-1
・Low-molecular organotin compounds such as ethylene-bis(
Diocarbons such as zinc dithiocarbamate, manganese ethylene-bis(dithiocarbamate), tetramethylthiuram molsulfide, zinc bis(dimethyldithiocarbamate), and their commonly used antifouling agents and disinfectants. It is necessary to use either alone or in combination. If the resin contains a monomer with a free carboxyl group such as (meth)acrylic acid as a constituent component, it may react with cuprous oxide or thiocarbamates, causing thickening or gelation during storage of the paint. So I don't like it.

Since the resin used as a vehicle in the present invention is itself slightly water-soluble, it is not necessary to use an elution aid such as rosin, although it may be used.

Although the present invention has been mainly described as a self-polishing antifouling paint, the present invention is also applicable to fishing net paints, paints for fishing nets,
It is clear that the present invention can be applied to all fields that require slight solubility in seawater or water, such as encapsulating agents for agricultural chemicals and architectural paints.

Examples are shown below. In the examples, "part" means "part by weight", the viscosity is a value measured at 25° C., and the number average molecular weight of the resin was calculated in terms of polystyrene using the GPC method.

Example 1 40 parts of pheasant roll and 30 parts of dimethyl itaconate are added to a fourth flask equipped with a dropping funnel, a condenser, and a stirring melon, and heated to 90°C. Next, a mixed solution of 30 parts of methyl methacrylate, 20 parts of ethyl acrylate, 5 parts of acrylonitrile, 15 parts of n-butyl acrylate, and 1.2 parts of azobisisobutyronitrile was added dropwise to this solution over 4 hours. Thereafter, it was kept warm for 4 hours. During this time, the reaction temperature was 85-9
It was kept at 0°C. Next, 60 parts of pheasant roll was added.

Varnish A having a solid content concentration of 50.2%, a viscosity of 18 voids, and a resin number average molecular weight of 18,000 was applied.

Example 2 Using the same apparatus as in Example 1, 50 parts of kijirole and 50 parts of dibutyl itaconate were added and kept at 85°C. Next, a mixed solution of 30 parts of methyl methacrylate, 20 parts of ethyl acrylate, and 1.2 parts of abbisisobutyronitrile was added dropwise to this solution over 4 hours, and then kept warm for 4 hours. During this time, the reaction temperature was maintained at 80-85°C.

Next, add 50 parts of Kijiroru, solid content concentration 49.8%,
Varnish B having a viscosity of 16 voids and a resin number average molecular weight of 17,000 was obtained.

Example 3 Using the same apparatus as in Example 1, 50 parts of kijirole and 70 parts of dimethyl itaconate were added and kept at 85°C. Next, a mixed solution of 10 parts of methyl methacrylate, 20 parts of ethyl acrylate, and 162 parts of azobisisobutyronitrile was added dropwise into this solution over 4 hours, and then kept warm for 4 hours. During this time, the reaction temperature was maintained at 80-85°C.

Next, add 50 parts of Kijiroru, solid content concentration 50.3%,
Varnish C having a viscosity of I6 voids and a resin number average molecular weight of 17,000 was obtained.

Example 4 Using the same equipment as in Example 1, Kijiroll 500 1 part, and 50 parts of dimethyl itaconate were added and kept at 85°C.

In this solution, 30 parts of methyl methacrylate, 10 parts of ethyl acrylate, 5 parts of methyl acrylate, 5 parts of 2-hydroxyethyl acrylate, 1.0 parts of azohisisobutyronitrile.
Two parts of the mixed solution were added dropwise over 4 hours, and then kept warm for 4 hours. During this time, the reaction temperature is maintained at 80-85°C. Next, add 50 parts of pheasant roll, solid content concentration is 48.9%, viscosity is 2.
1 boiz.

Varnish D having a resin number average molecular weight of 18,000 was obtained.

Example 5 Using the same apparatus as in Example 1, 50 parts of quidylol, 25 parts of dimethyl itaconate, 20 parts of 2-ethylhexyl itaconate, and 5 parts of vinyl acetate were added, and the mixture was kept at 80°C. In this solution, 30 parts of methyl methacrylate, 5 parts of ethyl acrylate,
A mixed solution of 10 parts of methyl acrylate, 5 parts of 2-hydroxyethyl acrylate, and 1.5 parts of benzoyl peroxide was added dropwise over 5 hours, and then kept warm for 4 hours. During this time, the reaction temperature is maintained at 75-80°C. Next, 50 parts of pheasant roll were added to give a solid content of 49.6% and a viscosity of 20 boids.

1 Varnish E having a resin number average molecular weight of 18,000 was obtained.

Comparative Example 1 Using the same apparatus as in Example 1, 40 parts of kijirole and 50 parts of dimethyl maleate were added and kept at 85°C. Next, a mixed solution of 20 parts of methyl methacrylate, 30 parts of ethyl acrylate, and 1.5 parts of hendiyl peroxide was added dropwise over 4 hours, and then kept warm for 4 hours. During this time, the reaction temperature was 80-8
It was kept at 5°C.

Next, 60 parts of Kijirole was added to give a solid content concentration of 43.2%.

A comparative varnish Δ having a viscosity of 3.1 voids and a number average molecular weight of resin +7000 was obtained.

Comparative Example 2 Using the same equipment as in Example 1, Kishi! Add 50 parts of dimethyl maleate, 50 parts of dimethyl maleate, and maintain the temperature at 80"C. In this solution, 60 parts of tributyltin methacrylate, 30 parts of methyl methacrylate, 10 parts of isobutyl methacrylate, 1.5 parts of peroxide, and peroxide. A mixed solution of was added dropwise over 4 hours and then kept warm for 3 hours.
It was kept at ~85°C. Next, 50 parts of Kijiroru were added, solid content concentration was 52.0.2%, viscosity was 5.6 voids, and the number average molecular weight of the resin was 15.
A comparative varnish B of 0.000 was obtained.

The resin varnish used in Comparative Varnish B is a system that has been put to practical use as a hydrolyzable polymeric organic mono- to realkyl tin compound.

Comparative Example 3 Vinyl chloride resin V A G I- manufactured by UCCCC, USA
Compare 50% methyl isobutyl ketone solution of T Varnish C
shall be.

The resin varnishes in Examples and Comparative Examples either do not have antifouling properties or have poor antifouling properties, so in order to clarify the characteristics of the resins, they were dispersed in a ball mill using the paint formulations shown in Table 1. Antifouling paints were manufactured and tested. The test results are shown in Table 1.

(Left below) 3 Paint rate H Mema Takeo IL! Experience-ζma! In the storage stability test for Fururi paint, 250 cc of the paint was sealed in a glass container with a capacity of 300 cc, and the condition of the paint (change in viscosity) was examined after storing it at 50° C. for 2 months. The results are shown in Table 2.

Table 2 From the above results, the antifouling paint using the resin composition according to the present invention has very good storage stability.

□Kudzu and 112 Hair-1 and its U A test plate coated with a test paint to a constant film thickness was attached to a disrotor plate and heated at a constant speed (circumferential speed approximately 35 knots) in seawater (water temperature 17-522°C). 60 "1"
The coating was rotated day and night, and the degree of wear was measured by observing the cross section of the coating film with a microscope, and the degree of wear was measured according to the following formula based on comparison with that before the test.

The results are shown in Table 3.

Table 3: Results of paint film wear test From the above results, the cleaning action of the antifouling paint using the resin composition of the present invention is clear.

6. A sandblasted test steel plate of the size of a crane was brushed twice so that the dry film thickness was approximately 100 It per coat to prepare an antifouling performance test plate.

The antifouling performance test was conducted under the sea on a destabilizing raft in Aioi Bay, Hyogo Prefecture.
Meat + + 1i! by soaking in the water at a depth of 1 meter, and determining the amount of attached animals such as Fujibbo and Serpura, and plants such as Ulva and Green Nori as percentage of attached area! Evaluation was made by observation. The test results are shown in Table 4.

(Left below) 7 As is clear from the above results, the paint of the present invention has extremely excellent antifouling performance, and even after 36 months, 0% of organisms were attached.
Met.

From the above, the paint storage stability test results, paint film wear rate test results, and antifouling performance test results show that the paint of the present invention has excellent storage stability, maintains antifouling performance over a long period of time, and has an abrasive action. It can be said that it is an extremely excellent paint.

Patent applicant: Kuchimoto Paint Co., Ltd. Agent: Patent attorney Taku Akaoka! j 9

Claims (2)

[Claims] (1) A polymer of itaconic acid ester of the general formula (in the formula, R1+ R2 represents an alkyl having 1 to 8 carbon atoms), or an itaconic acid ester of the formula +a+ and an unsaturated monomer copolymerizable therewith. Self-polishing paint containing a copolymer with as a vehicle (2) Contains hydroxyl group in polymer structural unit (Mek)
A self-polishing paint according to claim 1 containing up to 10% by weight of acrylic ester.