JPH04224876A - Resin composition slightly soluble in water and coating material made by using it - Google Patents

Abstract

PURPOSE:To obtain the title composition which has a proper degree of slight solubility in water, gives a coating film with sufficient strength, and is suitable particularly for use as an antifouling paint by copolymerizing a compound of a specified formula and other ethylenically unsaturated monomer copolymerizable therewith. CONSTITUTION:5-40wt.% compound of the formula (wherein R1, R2,. and R3 are each H or CH3; n is 1 to 30) [e.g. polyethylene glycol mono (meth)acrylate or methoxypropylene glycol mono (meth)acrylate] is copolymerized with 95-60 wt.% other ethylenically unsaturated monomer copolymerizable therewith [e.g. methyl (meth)acrylate, octyl (meth)acrylate, styrene or hydroxyethyl (meth) acrylate] to give the title composition containing a copolymer having a glass transition point of -60 to 80 deg.C and a weight-average molecular weight of 10,000 to 150,000. This composition gives a strong coating film with a proper degree of wearability; therefore, when it is used as a vehicle in an antifouling paint, an antifouling agent can be released stably over a long period of time.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slightly water-soluble resin composition useful as a vehicle for antifouling paints and providing suitable slightly water-soluble properties and sufficient coating strength, and to paints made using the same.

0002

[Prior Art] Conventionally, submerged parts of ships and offshore structures are
To prevent corrosion due to the attachment of sea creatures such as barnacles, snails, sea squirts, and algae, and to prevent a decrease in the sailing speed of ships, and to prevent the death of fish and shellfish due to the attachment of sea creatures to aquaculture nets and wire meshes. Antifouling paints made by blending antifouling agents with vehicle components such as toughener, rosin, and plasticizers, or Japanese Patent Publication No. 40-21426, Japanese Patent Publication No. 51-1204
As shown in Publication No. 9, etc., an antifouling paint using a polymer or copolymer of an organotin-containing unsaturated monomer is applied, and the paint film is continuously and gradually eluted in seawater.
It shows antifouling effect.

0003

[Problem to be solved by the invention] The former type of paint exhibits an antifouling effect by eluting the rosin and antifouling agent components contained in the coating film obtained from it, but the coating film does not last for a long time. When immersed in seawater, the amount of insoluble components increases and the coated surface becomes uneven, making it less effective in preventing the adhesion of marine organisms. The latter coating is produced by immersing a coating film containing an organotin compound introduced into the polymer via an ester bond in seawater, and hydrolyzing the ester bond to separate the organotin compound and convert it into a carboxyl group. A polymer containing

[0004] This polymer dissolves in seawater, always exposing a fresh coating film and maintaining antifouling properties. However, in order to effectively exhibit the antifouling properties of the coating film, many toxic organic tin compounds are generally introduced, which has the disadvantage of having an adverse effect on seafood.

[0005] The present invention was achieved as a result of intensive study in view of the existence of various drawbacks in these conventional techniques. The object of the present invention is to provide a slightly water-soluble resin composition that has high properties and can continuously form a new coating film, and a paint made using the same.

[0006]

[Means for Solving the Problems] That is, the present invention provides general formula (I)

5 to 40% by weight of the compound represented by [Chemical formula 2] (wherein R1, R2 and R3 are H or CH3, and n is 1 to 30), and other ethylenically unsaturated monomers copolymerizable with the compound body 9
A slightly water-soluble resin composition containing a copolymer obtained by copolymerizing 5 to 60% by weight and having a glass transition point of -60°C to 80°C and a weight average molecular weight of 10,000 to 150,000, The present invention also relates to a coating material using the slightly water-soluble resin composition.

The compound represented by the general formula (I) used in the present invention is a known compound, and specifically, polyethylene glycol monomethacrylate, polyethylene glycol monoacrylate, methoxypolyethylene glycol monomethacrylate, methoxypolyethylene glycol Examples include monoacrylate, polypropylene glycol monomethacrylate, polypropylene glycol monoacrylate, methoxypolypropylene glycol monomethacrylate, and methoxypolypropylene glycol monoacrylate.

The blending amount of these compounds is 5 to 40% by weight, preferably 5 to 40% by weight based on the total monomers used in the polymerization.
~30% by weight. If the amount is less than 5% by weight, there is no dissolution in the initial and long term in terms of slight water solubility, and there is almost no antifouling effect. On the other hand, if it exceeds 40% by weight, the water resistance of the coating film will be poor and it will not be possible to obtain a good coating film. From both of these points, the above-mentioned items 5 to 30 are particularly excellent in terms of antifouling effect.
% by weight.

Further, as other ethylenically unsaturated monomers that can be copolymerized with these compounds, for example, the following can be used.

(a) Esters of acrylic acid or methacrylic acid; for example, methyl acrylate, ethyl acrylate, propyl acrylate, isopropy acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate, methyl methacrylate , ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl methacrylate, lauryl methacrylate, etc.

(b) Vinyl aromatic compounds; for example, styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene, etc.

(c) Hydroxyl group-containing monomer; for example, hydroxyalkyl esters of acrylic acid or methacrylic acid such as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, and hydroxypropyl methacrylate.

(d) Others; acrylonitrile, methacrylonitrile, vinyl acetate, etc. These ethylenically unsaturated monomers can be used alone or in combination of two or more. The above unsaturated monomers include film strength,
It is preferable to mainly use alkyl esters of acrylic acid or methacrylic acid, styrene, etc. because they have excellent coating performance such as salt water resistance.

In the present invention, the glass transition point (Tg) of the copolymer obtained by copolymerizing these monomers is -60°C.
-80°C, preferably -30°C to 40°C,
Particularly preferred is -20°C to 30°C. Here, Tg
If the temperature is below -60°C, the coating film will swell and whiten severely, while if it exceeds 80°C, cracks will occur in the coating film.

It should be noted that the glass transition point (Tg
) means the theoretical glass transition point calculated by the following formula (however, Tg in the following formula is absolute temperature). 1/Tg=ΣWn/Tgn [where n is the name of the monomer, Wn is the weight fraction of monomer n with respect to the total monomer, and Tgn is the glass of the homopolymer of monomer n. It is the transition point (absolute temperature). ] Therefore, the glass transition point can be adjusted by adjusting the type and blending ratio of the monomers to be blended.

In the present invention, a copolymer with a low glass transition point is advantageous for aquaculture nets that require flexibility, while a copolymer with a high glass transition temperature is advantageous for use in places with high water resistance such as ships. Preference is given to point copolymers.

Copolymerization of these monomers can be carried out, if necessary, using an organic solvent such as xylene, toluene, methyl isobutyl ketone, butyl acetate, cellosolve acetate, etc. as a reaction solvent or diluent solvent. As the polymerization catalyst, peroxide radical initiators such as benzoyl peroxide and ditertiary butyl peroxide, and azo radical initiators such as azobisisobutyronitrile and azobisvaleronitrile are used. Solution polymerization is preferred because it is simple, but suspension polymerization, bulk polymerization, ionic polymerization, photopolymerization, radiation polymerization, etc. can also be used.

The weight average molecular weight of the resulting copolymer is preferably from 10,000 to 150,000, more preferably from 15,000 to 100,000, and particularly preferably from 50,000 to 90,000 in terms of the balance between the two. . If the weight average molecular weight is less than 10,000, the water resistance of the coating film will be poor and whitening will easily occur, while if it exceeds 150,000, the solubility in water will be poor and it will be impractical in terms of painting workability.

[0019] The weight average molecular weight in the present invention is
This is a value measured by gel permeation chromatography and converted using a standard polystyrene calibration curve.

The copolymer thus obtained is contained as a main component in the slightly water-soluble resin composition of the present invention. The slightly water-soluble resin composition of the present invention can also contain other known resins to the extent that the good slightly water-soluble resin composition of the copolymer is not impaired.

The slightly water-soluble resin composition of the present invention can be made into an antifouling paint by adding known antifouling agents, pigments, etc., if necessary.

Typical antifouling agents include zinc oxide, zinc chromate, strontium chromate, cupric chromate, cupric citrate, cupric ferrocyanate, cupric quinoline, and δ- Hydroquinone cupric, cupric oleate,
These include cupric nitrate, cupric phosphate, cupric tartrate, cuprous oxide, cuprous iodide, or cuprous sulfite.

On the other hand, typical pigments include inorganic pigments such as titanium oxide (titanium white), iron oxide, and carbon black, and organic pigments such as azo, cyanine, and quinacridine pigments. , usually inorganic pigments are used.

[0024] Furthermore, there is no hindrance to the combined use of organic tin compounds, triazine compounds, organic sulfur compounds, etc. as antifouling agents.

Furthermore, it is also possible to use rosin, gum rosin, wood rosin, tall oil rosin, etc. as an elution aid. The paint of the present invention thus obtained is useful as a ship bottom paint, a paint for fishing nets, and the like.

[0026]

[Example] Next, an example of the present invention will be shown. Hereinafter, “Department” means “
"Parts by weight" and "%" mean "% by weight". Examples 1 to 13 Methoxypolyethylene glycol monomethacrylate (Blenmar PME-100, manufactured by NOF Corporation, saponification value 290 ~ 300KOHmg/g
, acid value 0.33 or less, number average molecular weight approximately 190, homopolymer Tg - 85°C) were charged into a flask in the amounts shown in Table 1 (as solid content), and then n-butanol was added to methoxypolyethylene glycol monomethacrylate. Pour into a flask so that the solid content is 25%. Then, adjust the solid content in the flask to 37.5% with xylene. After that, the temperature was raised to 110 ° C., and methyl methacrylate (Tg of homopolymer 105 ° C.) with the blending amount shown in Table 1,
0.0 g of azobisisobutyronitrile per 100 g of a mixture of butyl acrylate (homopolymer Tg - 54°C).
After dropping the mixed solution at a ratio of 7g over 2 hours, it was kept at the same temperature for another 1 hour, and then heated to 130℃.
The copolymer was obtained by raising the temperature to 99.9% and causing the reaction to reach a polymerization rate of 99.9% or more.

A solvent (xylene) was added to the obtained copolymer so that the solid content was about 50%. Table 1 shows the heating residue, viscosity, theoretical glass transition point, and weight average molecular weight of the obtained copolymer solution.

[0028]

[Table 1]

Examples 14-22 Methoxypolyethylene glycol monomethacrylate (
Table 2 Table 2
Example 1 was carried out in exactly the same manner as in Example 1, except for using the monomer blend shown in . Table 2 shows the formulation, heating residue, viscosity, theoretical glass transition point, and weight average molecular weight.

Comparative Example 1 30 parts of xylene, 10 parts of methyl methacrylate, and 19 parts of butyl acrylate were charged into a four-necked flask similar to that in Example, and the temperature was raised to 130°C. Then, a mixture consisting of 22 parts of methyl methacrylate, 49 parts of butyl acrylate, and 0.2 parts of benzoyl peroxide was added dropwise over 2 hours, kept at the same temperature for another 1 hour, and then raised to 140°C. The mixture was kept warm for 3 hours and reacted to a polymerization rate of 99.9% or higher to obtain a copolymer. The obtained copolymer was diluted in the same manner as in Example 1. Table 2 shows the formulation, heating residue, viscosity, theoretical glass transition point, and weight average molecular weight.

Comparative Example 2 The same procedure as Comparative Example 1 was carried out except that the monomer blending ratio was changed as shown in Table 2. However, the monomers initially charged were the same as in Comparative Example 1, and 67 parts of methyl methacrylate and 4 parts of butyl acrylate were added later.

[0032]

[Table 2]

Coating Film Evaluation The copolymers shown in Tables 1 and 2 were coated in a 10 cm x 20 cm x
It was applied to a 3 mm single-sided ground glass plate to a dry film thickness of 50 μm, dried at 100°C for 4 hours, then immersed in 1 knot of flowing seawater (20°C), and the change in weight of the film was measured to determine the wear rate ( %) was calculated. The weight of the test piece after immersion was measured after drying at 110°C for 1 hour. Consumption rate (%) = (
Initial dry coating plate weight - dry coating plate weight after aging) / (initial dry coating plate weight - glass plate weight) x 100

0034
] Furthermore, the appearance of the coating film after 3 months was observed and judged according to the following criteria. ○: No abnormality △: Slight whitening ×: The whitening test results are summarized in Table 3.

[0035]

[Table 3]

[0036]

Effects of the Invention The slightly water-soluble resin composition of the present invention has a strong coating film and moderate coating wear resistance, so when used in an antifouling paint, it is easy to select an antifouling agent. Furthermore, the antifouling agent can be stably eluted over a long period of time. Therefore, it is extremely useful for coating the surfaces of ship bottoms, underwater structures, etc., and coating nets for aquaculture.

Claims (3)

[Claims] Claim 1: 5 to 40% by weight of a compound represented by general formula (I) [Formula 1] (wherein R1, R2 and R3 are H or CH3, and n is 1 to 30), and copolymerized therewith. Possible other ethylenically unsaturated monomers 9
A slightly water-soluble resin composition containing a copolymer obtained by copolymerizing 5 to 60% by weight and having a glass transition point of -60°C to 80°C and a weight average molecular weight of 10,000 to 150,000. [Claim 2] The glass transition point of the copolymer is -30°C ~
The slightly water-soluble resin composition according to claim 1, wherein the temperature is 40°C. 3. A paint comprising the slightly water-soluble resin composition according to claim 1 or 2.