JPH02214719A - Hydrolytic polymer, its production, resin for antifouling paint and decomposable plastics - Google Patents

Abstract

PURPOSE:To obtain a polymer which is useful as a resin for antifouling paint used in boat, fishing net or the like, because it is readily hydrolyzable into low-molecular weight polymers under natural conditions such as in marine water by effecting radical polymerization of a monomer composition of cyclic ketene acetal and introducing ester bonds into the main chain of the resultant polymer. CONSTITUTION:A monomer composition containing, as an essential component, a cyclic ketene acetal, (preferably 2-methylene 1,3-dioxolane, 2-methylene-1,3- dioxane, 2-methylene-1,3-dioxepan), is radically polymerized and ester bonds are introduced into the main chain of the polymer to give the subject polymer. It is preferred that the recurring units of ester bonds originating from the cyclic ketene acetal is included in the polymer more than 0.1mole%.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a self-polishing resin or a degradable resin for antifouling paint for the purpose of preventing the adhesion of aquatic organisms to structures such as ships, fishing nets, and drainage channels. Plastics (prior technology) In recent years, in the field of antifouling paints, hydrated resins have been used as self-polishing resins that can keep the paint surface clean by gradually hydrolyzing and dissolving the paint film. Degradable polycarbonate is attracting attention. Furthermore, since plastics become a source of environmental pollution as industrial waste after use, degradable plastics using easily degradable polymers are strongly desired.

Examples of polymers incorporating easily decomposable chemical bonds include acrylic polymers copolymerized with methacrylic acid triphenylmethyl ester described in JP-A-61-261374, and methacrylic acid-based polymers described in JP-A-58-98313. Some polymers, such as ionomers, have a hydrolyzable carboxylic acid ester bond or carboxylic acid metal salt bond incorporated in the polymer side chain, and both of these are being considered for use in antifouling paints. It is also disclosed in Nikkei New Materials, December 7, 1987, page 14, as a polymer incorporating a hydrolyzable ester bond in its main chain. Subject to hydrolysis (biodegradation) by microorganisms. There is a 3-hydroxybutyrate polyester.

(Problems to be Solved by the Invention) However, the former polymer in which a carboxylic acid ester bond or a carboxylic acid metal salt bond is incorporated in the polymer side chain has a drawback that the change in molecular weight due to hydrolysis is small. Furthermore, the latter 3-hydroxybutyrate-based polyester has the disadvantage that it is difficult to mass-produce it because it is produced using microorganisms.

By incorporating a hydrolyzable ester bond into the main chain, the present invention decomposes into low molecular weight substances during hydrolysis.
Furthermore, the present invention provides a hydrolyzable polymer that can be mass-produced and a method for producing the same.

Further, the present invention provides a resin for antifouling paints and degradable plastics containing the hydrolyzable polymer.

(Another Means to Solve the Problems) That is, the present invention is obtained by polymerizing a monomer composition containing a cyclic ketene acetal as an essential component.

The present invention relates to a hydrolyzable polymer having an ester bond in its main chain, a method for producing the same, and resins for antifouling paints and degradable plastics containing the same.

In the present invention, the cyclic ketene acetal is represented by the following general formula (1).

(However, R represents a divalent organic group) Specific compounds include 2-methylene-1,3-dioxolane and 2-methylene-1,3-dioxane.

2-methylene-1,3-dioxolane and derivatives thereof are exemplified as preferred because they are easily ring-opening polymerized.

In particular, when 2-methylene-1,3-dioxolane or its derivatives are used, the probability of ring-opening polymerization of the compound is io
Since it is close to o*, more ester bonds can be introduced into the polymer main chain, which is preferable.

In the present invention, ester bonds can be incorporated into the polymer main chain by combining one or more types of cyclic ketene acecures such as 9 or more with other monomers and copolymerizing them. Regarding this point, please refer to the journal
Of Polymer Sci Engineering: / Su (Journal of
Polymer 5science) Volume 20 (19
82) W, J described on page 3021.

It is detailed in the literature by Bai 1 ey.

In the present invention, other monomers to be copolymerized include methyl ester, ethyl ester, propyl ester, butyl ester, phenyl ester, chloroethyl ester, furomoethyl ester, chlorophenyl ester, trifluoroethyl ester of acrylic acid or methacrylic acid. acrylic ester or methacrylic ester monomers such as, styrene monomers such as styrene, α-methylstyrene, pt-butylstyrene, and vinyl chloride.

Vinyl monomers such as vinyl acetate, ethylene, propylene, butadiene, chloroprene, isoprene, etc. are mainly used.

Depending on the purpose, acrylic acid, methacrylic acid, glycidyl acrylate, glycidyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate,
Hydroxypropyl acrylate, hydroxypropyl methacrylate.

Monomers such as N-vinylpyrrolidone and derivatives thereof may be copolymerized.

The hydrolyzable polymer of the present invention comprises the above-mentioned monomer composition,
It can be obtained by radical polymerization using solution polymerization, suspension polymerization, bulk polymerization, or the like.

As the radical polymerization initiator, conventionally known azo compounds and peroxides such as azobisisobutyronitrile and benzoyl peroxide can be used. For example 2-
Methylene-1,3-dioxebane and other monomers are blended and solution polymerized in various solvents in the presence of a radical polymerization initiator. A hydrolyzable polymer can be obtained from this by removing the solvent and unreacted monomers.

The hydrolyzable polymer obtained as described above is as follows.

It is preferable that the polymer contains 0.1 mole or more of a repeating unit containing an ester bond formed from a cyclic ketene acetal. If it is less than 0.1 molar, the hydrolyzability will decrease and the rate of decrease in the molecular weight of the hydrolyzed polymer will also decrease.

The hydrolyzable polymer of the present invention can be used as a resin for antifouling paint. In this case, other resins commonly used for antifouling paints (e.g.

(co)polymers of vinyl monomers exemplified above, etc.) can be blended. Hydrolyzable polymers.

In order to fully exhibit its properties, it is preferably blended in an amount of 20 to 100% by weight in the resin (composition) for antifouling paint.

Known colorants and various additives can be used in the antifouling paint.

In addition, other known antifouling agents 9 such as suboxide steel, rhodanized steel, organotin compounds, organotin polymers,
A thiocarbamate or the like may be used in combination.

The hydrolyzable polymers of the invention can be used as 9-degradable plastics. Products using this degradable plastic include films for greenhouse gardening,
Food packaging films, detergents.

Examples include, but are not limited to, containers for storing hair styling products, food, etc., and raw materials for cushioning materials. Moreover, the method for producing them only requires the use of two hydrolyzable polymers of the present invention as components.

This can be done by conventional methods.

(Example) The present invention will be described with reference to an example, but the present invention is not limited thereto.

Synthesis Example 1 Chloroacetaldehyde dimethyl acetal 509 (0
The ion exchange resin Dowex 50 (Na
) (manufactured by DuPont) 0.5971El, t200mj
The mixture was refluxed at 115° C. in a 7 flask. The reaction was stopped when 0.8 mol of methanol was distilled out (3 hours).

Dowex 50 was removed by filtration. Distill the reaction solution.

2-chloromethyl-1,3-dioxepane was obtained.

In a 200°C flask, 2-chloromethyl-1°3-dioxepane 2149 (0.2 mol) was added dropwise to a mixture of 37 tetrahydro 7ranes and potassium t-butoxide 309 (0.2 mol) at 60°C. Suru. After the addition, the flask temperature was raised to 80"C and refluxed for 7 hours. The reaction was stopped, 100% diethyl ether was added, and KC1! was removed by filtration. Further distillation was performed to obtain 2-methylene-1,3-dioxebane t- Obtained.

Synthesis Example 2 1 g of 2-methylene-1,3-dioxe pan obtained in Synthesis Example 1, 9 g of styrene, and 0.2 g of toluene, 40 ae, 2° τ-azobisisobutyronitrile, were placed in a 100-ml flask and stirred. The reaction was carried out at 80° C. for 6 hours. After dropping the reaction solution into a large excess (approximately 20 times the amount) of methanol to precipitate the copolymer.

Filter and dry to obtain 2-methylene-1゜3- as shown in Table 1.
Dioxymopan/styrene copolymer (hydrolyzable polymer)
I got it.

Synthesis Example 3 In Synthesis Example 2, 2-methylene-1,3-dioxepane 29. A 2-methylene-1,3-dioquimopane/styrene copolymer (hydrolyzable polymer) was obtained using the same pressure as in Synthesis Example 2, except that 8 g of styrene was used.

Synthesis Example 4 In Synthesis Example 2, 2-/? shown in Table 1 was prepared in exactly the same manner as in Synthesis Example 2, except that 3 g of 2-methylene-1,3-dioxepane compound and 79 g of styrene were used. L/n-1
, 3-dioxepane/styrene copolymer (hydrolyzable polymer) was obtained.

Synthesis Example 5 A styrene polymer was obtained in exactly the same manner as in Synthesis Example 2, except that all 2-methylene-1,3-dioxebane in Synthesis Example 2 was replaced with styrene.

Examples 1 to 3 and Comparative Examples The hydrolyzable polymers obtained in Synthesis Examples 2 to 5 were each made into a toluene solution with a resin solid content of 25 weight and applied to a plate glass of approximately 8 x 9 cm and dried to form a coating film with a thickness of 20 to 30 μm. I got it. This coating film was soaked in seawater (26°C).

pH & 12) for 200 days. Thereafter, this coating film was washed with water and dried, and subjected to gel permeation chromatography (GPC) analysis (standard polystyrene conversion) to observe changes in molecular weight before and after immersion. Table 1 summarizes the results.

The number average molecular weight of the 2-methylene-1,3-dioxebane copolymer decreases after immersion in seawater than before immersion.

The ratio of number average to weight average molecular weight also increased, indicating that it was sufficiently hydrolyzed by the sea and water.

(Effect of the invention) Examples and comparative examples 9 The hydrolyzable polymer of the present invention is 1
Under natural conditions, such as seawater, it breaks down into low molecular weight substances by hydrolysis. Therefore, it is useful as a resin-1 decomposable plastic for antifouling paint.

Claims (1)

[Scope of Claims] 1. A hydrolyzable polymer having an ester bond in its main chain, obtained by polymerizing a monomer composition containing a cyclic ketene acetal as an essential component. 2. The hydrolyzable polymer according to claim 1, which contains 0.1 mol% or more of a repeating unit containing an ester bond derived from a cyclic ketene acetal. 3. Cyclic ketene acetal is 2-methylene-1,3-
Dioxolane, 2-methylene-1,3-dioxane, 2
-methylene-1,3-dioxepane or a derivative thereof. 4. Cyclic ketene acetal is 2-methylene-1,3-
The hydrolyzable polymer according to claim 1 or 2, which is dioxepane or a derivative thereof. 5. A method for producing a hydrolyzable polymer, which comprises radically polymerizing a monomer composition containing a cyclic ketene acetal as an essential component to introduce an ester bond into the main chain. 6. A resin for antifouling paint containing the hydrolyzable polymer according to any one of claims 1 to 4. 7. Degradable plastics comprising the hydrolyzable polymer according to any one of claims 1 to 4.