DK172317B1 - Marine paints and acrylic polymers for use in marine paints - Google Patents

Description

in DK 172317 B1

This invention relates to a marine paint and acrylic polymers for use in this marine paint.

Marine paints are known in which a major component is a copolymer containing units of alkyl acrylates and 5-methacrylates as well as units of triorganotin esters of acrylic and methacrylates. Alkyl acrylate and methacrylate levels give the marine paint hardness when applied to a substrate and the triorganotin ester units produce a biocidal and self-polishing effect. During use, the 10 triorganotin units are decomposed from the polymer by hydrolysis and / or ion exchange to obtain a desired biocidal action. At the same time, the film is degraded, resulting in the self-polishing effect.

Thus, to obtain a satisfactory self-polishing effect, a certain amount of triorganotin units must be present in the copolymer used in the marine paint because the self-polishing effect is a consequence of the cleavage of these units. On the other hand, it is desirable to keep the amount of triorganotin units as low as possible, taking due account of the desired biocidal and self-polishing action, because the triorganotin monomers are quite expensive and additionally have a softening effect on the copolymer.

Copolymers of the above type are described, among others, in British Patent Specification No. 1,457,590.

According to Norwegian Patent Application No. 81 3553, it is proposed to replace some or all of the triorganotin units with methyl acrylate and / or ethyl acrylate units. The marine paint may contain another biocide, especially if the copolymer does not contain triorganotin ester units. The indicated methyl acrylate and ethyl acrylate units will to a certain extent be hydrolyzed in water and will give the paint applied a self-polishing effect. However, due to the low rate of hydrolysis of the resulting copolymer, the self-polishing effect will not be entirely satisfactory.

According to the invention, a marine paint of the kind specified in the preamble of claim 1 is provided, which paint is peculiar to that of the characterizing part of claim 1.

The additional units of formula CH2 = C-COO (CH2) n-O-R "

10 R

where R = H or CH3, R "= CH3 or C2H5, and n = 1 or 2, are readily hydrolyzed to form free carboxyl groups, resulting in a polymer which decomposes slowly to obtain a self-polishing effect.

15 Because of the content of units of monomer # 1, the film achieves sufficient hardness.

The copolymer used in the marine paint of the invention usually contains 15-80% by weight of monomer # 3 and 20-85% by weight of monomer # 1.

A preferred representative of monomer # 3 is 2-methoxy-oxyethyl acrylate, and a preferred representative of monomer # 1 is methyl methacrylate.

The marine paint in question may also, if desired, contain biocidal components to obtain the desired biocidal effect, such as cuprous oxide, dithiocarbamates and triorganoin compounds, as is known in the art.

In addition to the two monomer types described above, the copolymers used in the marine paint of the invention may also contain units of tri-organotin acrylates and methacrylates. Examples of such triorganotin monomers are tributyltin methacrylate and acrylate, tripropyltin methacrylate and acrylate and triphenyltin methacrylate and acrylate. The units of triorganotin monomers can comprise up to 60% by weight, especially 1-55% by weight of the copolymer (terpolymer). Units of monomer # 3 are then normally present in an amount of 1-80% by weight, especially 5-40% by weight, and units of monomer # 1 are then normally present in an amount of 20-85% by weight, especially 20-70% by weight.

The invention therefore also relates to acrylic terry polymers for use in the marine paint of the invention, which acrylic terry polymers are characterized by the characterizing part of claim 4.

The copolymers containing units of the monomers no.

1 and 3 can be prepared by usual polymerization of the monomers concerned using suitable initiators and under appropriate polymerization conditions. When it is desired to prepare a copolymer (terpolymer) which also contains triorganotin methacrylate or acrylate units, this can be done by either polymerizing monomers # 1 and 3 together with the desired triorganotin methacrylate or acrylate monomers, or monomers Nos. 1 and 3 can be polymerized with methacrylic or acrylic acid, and the carboxyl groups of the resulting polymer then esterified with triorganotin groups in a manner known in the other compound.

EXAMPLE 1 Methyl methacrylate (300 g; 3.00 mol) and 2-methoxyethyl acrylate (200 g; 1.54 mol) were dissolved in xylene (750 g). Azobisisobutyronitrile (4 g; 0.124 mol) was added and the solution was heated to 75 ° C, with stirring and under nitrogen.

The polymerization was carried out at the above temperature for a period of 5 hours and it was controlled by the change of refractive index.

The temperature was raised to 100 ° C for 30 minutes to destroy any residual activity of the initiator.

The resulting solution was a solution of a copolymer of methyl methacrylate and 2-methoxyethyl acrylate (60:40 on 10 weight basis).

EXAMPLE 2

Tributyltin methacrylate (150 g; 0.40 mol), methyl methacrylate (250 g; 2.50 mol) and 2-methoxyethyl acrylate (100 g; 0.77 mol) were dissolved in xylene (750 g).

Azobisisobutyronitrile (4 g; 0.02 mol) was added and polymerization was carried out in a similar manner to Example 1.

The resulting solution was a solution of a terpolymer of tributyltin methacrylate, methyl methacrylate and 2-methoxy oxyethyl acrylate (30:50:20) by weight.

EXAMPLE 3

Tributyltin methacrylate (275 g; 0.73 mol), methyl methacrylate (210 g; 210 mol) and 2-methoxyethyl acrylate (15 g; 0.12 mol) were dissolved in xylene (750 g).

Azobisisobutyronitrile (4 g; 0.02 mol) was added and polymerization was carried out in a similar manner to Example 1.

DK 172317 B1 5

The solution obtained was a solution of a terpolymer of tributyltin methacrylate, methyl methacrylate and 2-methoxyethyl acrylate (55: 42: 3 by weight).

EXAMPLE 4 409.2 g of the copolymer solution of Example 1 were mixed with cuprous oxide (365.4 g), zinc oxide (151.2 g), Aerosil (colloidal silica) (4.0 g), Bentone (thickener) (8.0 g), denatured ethanol (4.8 g) and xylene (57.4 g), and ground overnight to prepare a paint 10 by volume ratio of cuprous oxide to zinc oxide of 70:30.

EXAMPLE 5 409.2 g of the terpolymer solution of Example 2 was mixed with cuprous oxide (365.4 g), zinc oxide (151.2 g), aerosil (4.0 g), Bentone (8.0 g), denatured ethanol (4.8 g) and xylene (57.4 g), and ground overnight to prepare a paint having a ratio of cuprooxide to zinc oxide of 70:30 by volume.

Example 6 This example was carried out as Example 4, with the change that the polymer of Example 1 was replaced with the polymer prepared according to Example 3.

The paints described in Examples 4, 5 and 6 were tested for polishing using a rotary device with a 17 knots (about 31 km / h) peripheral speed in seawater at an average temperature of 23 ° C.

A commercially good self-polishing paint (X) containing organotin polymer was used as a reference. The test was conducted over a period of 90 days, and the thickness of the paint film was determined by electromagnetic induction.

Paint Polishing speed (μπι / year) X 60 5 Example 4 52

Example 5 72

Example 6 80

Claims (5)

A marine paint comprising a film-forming acrylic polymer containing units of monomers of formula 5 1. CH 2 * C-COOR 'ch 10 acrylates, characterized in that the acrylic polymer also contains units of monomers of the formula Marine paint according to claim 1, wherein the acrylic polymer contains units of 1. methylmethacrylate, 20 and optionally 2. tributyltin methacrylate, characterized in that the acrylic polymer also contains units of 3. 2-methoxyethyl acrylate. DK 172317 B1 3. CH2 = C-C00 (CH2) n-O-R "R 15 where R = H or CH3, R" = CH3 or C2H5, and n = 1 or 2. Marine paint according to claim 1 or 2, characterized in that the acrylic polymer contains 15 to 80% by weight units of monomer 3 and 20 to 85% by weight units of monomer 1, and optionally up to 60% by weight units 5 of monomer 2 . 3. CH2 = C-C00 (CH2) n-O-R "R 15 where R = H or CH3, R" = CH3 or C2H5f and n = 1 or 2. Acrylic terpolymer for use in the marine paint according to claims 1-3, characterized in that it contains units of the following monomers: CH2 = C-C00R '10 ch3 where R' is C1-4 alkyl, 2. triorganotin methacrylates or acrylates, and An acrylic polymer according to claim 4, characterized in that it contains units of: 1. methyl methacrylate, 2. tributyltin methacrylate and 3. 2-methoxyethyl arylate. An acrylic polymer according to claim 4 or 5, characterized in that it contains 20 to 85% by weight units of monomer 1, up to 60% by weight units of monomer 25. and 15 to 80% by weight units of monomer 3.