JPH0753899A - Polyester resin composition for antifouling coating - Google Patents

Abstract

PURPOSE:To obtain a novel polyester having proper hydrolytic property, useful for forming a resin coating film having excellent long-term alga-preventing property and deodorizing property and excellent in suitability for coating. CONSTITUTION:This polyester resin is a copolymer polyester composed of (A) a structural unit of the formula ORCH(CH2)nC deg. [R is H or a 1-3C alkyl; (n) is 0-4] and (B) 2-40C dicarboxylic acids (e.g. succinic acid or glutaric acid) and (C) 2-40C glycols (e.g. ethylene glycol or 1,3-propane diol) and the resin contains 20-95mol%, preferably 60-90mol% of the structural unit A. The copolymer polyester is, e.g. a copolymer polyester composed of 100 pts.wt. of lactic acid, 20 pts.wt. of adipic acid and 25 pts.wt of butanediol. The copolymer polyester can be obtained by dehydropolycondensaton or ring opening polymerization, etc.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention has a suitable level of hydrolyzability for resins, and therefore has excellent algae-proofing and shell-proofing properties for a long period of time, and has a smaller environmental load than ordinary hydrolyzable acrylic resins. The present invention relates to a polyester resin composition for antifouling paint, which provides an antifouling paint.

[0002]

2. Description of the Related Art Seaweeds and shellfish adhere to materials used in the sea such as bottoms of ships sailing in the ocean, fishing nets for aquaculture, and ropes and buoys that determine the positions of these, so This causes problems such as increased resistance, reduced work efficiency, reduced strength of materials and damage. The damage caused by the adhesion of these algae and shellfish is not limited to this, but seaweeds and shellfish adhere to the pipes and intake / discharge facilities of various industrial plants such as the inner wall of the intake pipe for cooling water of the nuclear power plant. It also causes problems such as water loss, damage due to an increase in tidal current resistance, damage, and a reduction in drainage capacity.

In order to prevent the seaweeds and shellfish of this kind from adhering as described above, conventionally, a hydrolyzable acrylic resin is mixed with an antifouling agent such as organic tin or cuprous oxide and applied. It happened. In particular, TBTO pendant type hydrolyzable acrylic resins have been widely used because they have good antifouling properties, but due to recent environmental problems, the legality has become stronger and the use of such resins has become difficult. Paint manufacturers are developing products that use various types of hydrolyzable acrylic resins. However, it is not an ideal resin because it may be contaminated with acrylic resin.

[0004]

In view of the above circumstances, the present invention has a long antifouling performance because it has biodegradability and therefore does not place a large load on the environment, and its hydrolysis rate is moderate. The present invention provides a polyester resin composition for antifouling paint, which can be maintained for a certain period.

[0005]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors to solve the above-mentioned problems, a polyester resin composition having the following composition is non-polluting and has long-term antifouling performance. The present invention has been found to be maintained, and the present invention has been achieved. That is, the present invention relates to structural units (I) and (II) having a structure of glycolic acid, lactic acid, 3-hydroxybutyrate, 3-hydroxyvalerate, caprolactone and the like having 2 to 2 carbon atoms.
A polyester obtained by copolymerizing 40 dicarboxylic acids and (III) glycols having 2 to 40 carbon atoms, wherein the structural unit (I) in the polymer accounts for 50 to 95 mol%. And a polyester resin for antifouling paint.

When the above polyester resin coating film is hydrolyzed by seawater, it becomes a naturally-occurring monomer such as glycolic acid and lactic acid, and the coating film surface is renewed. The hydrolyzed monomer is a naturally-occurring compound, and because it is incorporated into the metabolic process of marine organisms, the load on the environment is extremely small.

However, when polyglycolic acid, polylactic acid or the like is used as the polyester resin for the antifouling paint,
Since the hydrolysis rate is too fast, long-term antifouling property cannot be maintained. It is possible to increase the molecular weight in order to delay the hydrolysis rate, but it is difficult to increase the molecular weight only in consideration of the coating suitability of the coating material. Further, polyglycolic acid and polylactic acid are difficult to be dissolved in a general-purpose solvent such as toluene and xylene, so that it is difficult to use them as a coating resin.

As a result of intensive studies by the present inventors, glycoII, lactic acid, 3-hydroxybutyrate, 3-hydroxyvalerate, caprolactone and the like have (II) a carbon number of 2 to 40. 5 to 50 mol% of dicarboxylic acids and (II) glycols having 2 to 40 carbon atoms, preferably 10 to 40
It has been revealed that a polyester resin having an appropriate hydrolysis rate and excellent coating suitability can be obtained by copolymerizing by mol%.

The diol component in the present invention is ethylene glycol, 1,3-propanediol, 1,4-
Butanediol, 1,5-pentanediol, 1,8-
Octanediol, 1,10-decanediol, 1,1
2-dodecanediol, propylene glycol, 2,3
-Butanediol, 1,3-butanediol, neopentyl glycol and the like. From the viewpoint of safety of decomposed products, ethylene glycol and 1,4-butanedio-
And 2,3-butanediol are preferred.

As the dicarboxylic acid component in the present invention, succinic acid, glutaric acid, adipic acid, pimelic acid,
Examples thereof include suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, fumaric acid and dimer acid.

The molecular weight of the polyester resin in the present invention must be 2000 or more in consideration of the physical properties of the coating film.
000 or more is preferable. However, in consideration of coating suitability, it is necessary to be 200,000 or less, preferably 100,000 or less. The molecular weight in the present invention is a polystyrene-equivalent number average molecular weight measured by GPC.

The Tg of the polyester resin in the present invention is required to be 10 ° C. or higher in consideration of the physical properties of the coating film, and preferably 20 ° C. or higher.

The above polyester can be produced by a known method such as dehydration polycondensation or ring opening polymerization. Further, in the polyester in the present invention, polyvinyl alcohol, polyoxyalkylene glycol,
By mixing polymers such as polydioxane and polyamino acid, or inorganic substances such as talc, calcium carbonate and barium carbonate, it is possible to variously change the physical properties and decomposition characteristics of the film.

When adjusting the resin of the present invention to an antifouling paint, if necessary, an antifouling agent such as cuprous oxide, zinc dimethyldithiocarbamate, tetramethylthiuram disulfide, a pigment, and a viscosity adjusting agent may be added. Do. Hereinafter, details of the present invention will be described with reference to examples.

[0015]

【Example】

Example 1 Polymerization: PES-1 100 Lactic acid was placed in a reaction vessel equipped with a stirrer and a nitrogen introducing tube.
Parts by weight (hereinafter abbreviated as "parts"), 20 parts of adipic acid, 25 parts of butanediol, germanium oxide as a catalyst 0.0
4 parts was added and nitrogen substitution was performed 3 times. Under nitrogen stream, 1
The temperature was raised to 180 ° C. at 0 ° C./minute and stirred for 1 hour. Then, the pressure was reduced to 20 mmHg in 30 minutes, and the mixture was stirred for 1 hour. Further increase the degree of pressure reduction to 1 mmHg and at the same time 220
The temperature was raised to ℃ and the stirring reaction was continued for 3 hours to obtain polyester (PES-1). The composition is shown in Table 1.

Evaluation: PES-1 50 parts of the above polyester (PES-1) was dissolved in 100 parts of tetrahydrofuran, and then 50 parts of cuprous oxide was added and stirred. This paint was coated on a 20 cm × 20 cm primer-treated steel plate with a wire bar (50 #) and dried at 60 ° C. for 2 hours under a nitrogen stream. A steel sheet coated with an antifouling paint was subjected to a dipping test for 12 months at a depth of 1.5 m in the sea off Shirahama City, Wakayama Prefecture. The degree of adhesion of shellfish and algae was evaluated as an area ratio, and a 5-level evaluation was performed. The results are shown in Table 2.

Example 2 Polymerization: PES-2 Polyester was polymerized in the same manner as in Example 1. The composition is shown in Table 1. Evaluation: PES-2 The same evaluation as in Example 1 was performed. The results are shown in Table 2.

Example 3 Polymerization: PES-3 Polyester was polymerized in the same manner as in Example 1. The composition is shown in Table 1. Evaluation: PES-3 The same evaluation as in Example 1 was performed. The results are shown in Table 2.

Comparative Example 1 Polymerization: PES-4 Polyester was polymerized in the same manner as in Example 1. The composition is shown in Table 1. Evaluation: PES-4 The same evaluation as in Example 1 was performed. The results are shown in Table 2.

Comparative Example 2 Polymerization: PES-5 Polyester was polymerized in the same manner as in Example 1. The composition is shown in Table 1. Evaluation: PES-5 The same evaluation as in Example 1 was performed. The results are shown in Table 2.

Comparative Example 3 Polymerization: PES-6 194 parts of dimethyl terephthalate, 194 parts of dimethyl isophthalate, 136 parts of ethylene glycol and 229 parts of neopentyl glycol were placed in a four-necked flask. Transesterification catalyst Tetra-n-butyl titanate (TB
T) 0.1 part was added, and the mixture was stirred at 180 ° C. under normal pressure for transesterification. After 128 parts of methanol was distilled off, the pressure was reduced to 1 mmHg and polymerization was carried out at 230 ° C. to produce polyester (PES). -5) was obtained. The composition is shown in Table 1. Evaluation: PES-6 The same evaluation as in Example 1 was performed. The results are shown in Table 2.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

EFFECTS OF THE INVENTION As is clear from the results shown in Table 2, a polyester resin composition for antifouling paint having excellent anti-biofouling property was obtained by the present invention.

Claims (1)

[Claims] 1. A structural unit of structural formula (I) and the following (II),
(III) [Chemical formula 1] A polyester resin composition for antifouling paints, characterized in that the proportion of the structural unit (I) in the polymer is 50 to 95 mol%. (II) C2-C40 dicarboxylic acids (III) C2-C40 glycols