JP2004124102A - Method of treating easily decomposable polymer resin and easily decomposable resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of treating an easily decomposable polymer resin and an easily decomposable resin composition which is possible of sharply improving decomposability by a relatively mild chemical and biochemical treatment without spoiling adhesion properties or adhesive properties to various kinds of stocks with the aim of decomposition or dissolving elimination at a time of disposal or in a recycling process. <P>SOLUTION: In the method of decomposition treating the easily decomposable resin composition comprising the easily decomposable polymer resin and a binder resin, where the easily decomposable macromolecular resin is a polyvinyl acetal resin, the method of treating the easily decomposable polymer and the easily decomposable resin composition comprises acid-hydrolyzing the polyvinyl acetal resin and converting at least part of the acetal resin to a polyvinyl alcohol. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a method for treating a readily degradable polymer resin and a readily degradable resin composition which can be applied to plastic paints, plating primers and the like used for plastic products such as home appliances.

Environmental pollution of the earth has become apparent, and it is necessary to consider the environment not only of industrial waste but also of household waste. Under these circumstances, synthetic resins (plastics), which are industrial materials, are no exception, and research and development of waste resin treatment methods that reduce the burden on the environment and equipment that can process large amounts of waste resin are required. Have been.

従 来 Conventional methods for treating waste resin that reduce the burden on the environment include, for example, incineration or landfill of low-molecular-weight waste resin by thermal decomposition or chemical decomposition. However, since incineration involves the emission of carbon dioxide, it causes global warming, and if the incinerated resin contains halogen, sulfur, nitrogen, etc., harmful gases are generated and air pollution occurs. It can be the cause of When landfilling waste resin, most resins that are currently in practical use will remain intact without being decomposed for a long time. Additives and the like contained in the resin buried during this period flow out, which is one of the causes of soil contamination.

In response to such problems, biodegradable resins have been actively developed as polymer compounds that do not adversely affect the global environment and the like when they are disposed of (for example, JP-A-5-287043). etc). Also, various recycling methods for reusing such a resin have been studied.

However, when such biodegradable resins are used or recycled, surface treatment materials such as coating and plating applied to these resins become problems. In other words, if a plastic product is painted to enhance its aesthetic appearance, or if it is plated for electromagnetic wave shielding, even if a biodegradable raw resin is used, the resin will be decomposed due to the coating and plating. In some cases, it is not used or when it is recycled, it is mixed as an impurity and cannot be reused.

プ ラ イ マ ー Also, even if the plating film itself was corroded to some extent, the primer as a base remained, hindering biodegradation and recycling.

JP-A-5-287043

The present invention aims to decompose or dissolve and desorb at the time of disposal or in the recycling process, and greatly decomposes by relatively mild chemical and biochemical treatment without impairing adhesion or adhesion to various materials. An object of the present invention is to provide a readily degradable polymer and a method for treating the composition, which can be improved.

That is, the above object is achieved by the following configuration of the present invention.
(1) A method for treating a readily decomposable polymer resin in which a polyvinyl acetal resin is acid-hydrolyzed and at least a part thereof is converted into polyvinyl alcohol.
(2) A method for treating an easily decomposable resin composition comprising an easily decomposable polymer resin and a binder resin, wherein the easily decomposable polymer resin is a polyvinyl acetal resin. A method for treating an easily decomposable polymer that hydrolyzes and converts at least a part thereof into polyvinyl alcohol.
(3) The binder resin is a thermoplastic acrylic resin, and the easily decomposable polymer resin and the binder resin are converted to a mass ratio of a polyvinyl acetal resin to a thermoplastic acrylic resin in a range of 100: 0 to 70 (however, 0 is not included) The method for treating the easily decomposable resin composition according to the above (2).
(4) The method for treating an easily decomposable resin composition according to the above (2) or (3), wherein the thermoplastic acrylic resin is a homopolymer.
(5) The method for treating an easily decomposable resin composition according to any one of the above (2) to (4), wherein the easily decomposable resin composition is a coating film of a plastic resin or a primer material.
(6) The method for treating an easily decomposable resin composition according to any one of the above (2) to (5), wherein the easily decomposable resin composition further contains a chitosan derivative.

According to the present invention, for the purpose of decomposition or dissolution and desorption at the time of disposal or in the recycling process, without deteriorating the adhesion to various materials, or the adhesion, it can be degraded by relatively mild chemical and biochemical treatment. And a method for treating a readily decomposable polymer and a composition thereof, which can significantly improve the composition.

The easily decomposable resin composition of the present invention contains an easily decomposable polymer and a binder resin, wherein the easily decomposable polymer is a polyvinyl acetal resin, and preferably, the binder resin is a thermoplastic acrylic resin. .

(4) As described above, by containing the easily decomposable polymer and the binder resin, a decomposability is greatly improved, and a resin composition capable of firmly bonding and adhering to a substrate is obtained.

種 々 Various polymers are known as easily decomposable polymers, but in the present invention, a polyvinyl acetal resin such as a polyvinyl butyral resin is used. As described later, at least a part of the polyvinyl acetal resin is easily converted to polyvinyl alcohol by an acid hydrolysis treatment.

As shown in the following formula (I), the polyvinyl acetal resin has three components of a vinyl acetal structure, a vinyl alcohol structure, and a vinyl acetate structure in a molecular chain, and has excellent solubility in various solvents including a polar solvent. ing. The ratio of the vinyl acetal structure, vinyl alcohol structure and vinyl acetate structure is usually about 69 to 85:10 to 25: 0.5 to 15 by mass. Further, polyvinyl acetal resin is superior in water resistance, durability, and adhesion as compared with polyvinyl ketal resin and the like. The average degree of polymerization of the polyvinyl acetal resin is not particularly limited, but is usually about 50 to 5000, Tg is about 65 to 95 ° C., and the solution viscosity is about 10 to 250 cps.

特 に Particularly, the vinyl acetal structure can be easily converted to vinyl alcohol known to be biodegradable by acid hydrolysis, as shown in the following formula.

Accordingly, by combining the polyvinyl acetal resin with various other resins, a resin composition having easy decomposability or biodegradability can be obtained. These can be applied to coating agents, inks, paints, adhesives, films, binders, plating primers, and the like.

Especially, application to plastic paints, which previously hindered the recyclability of plastic products, makes it easier to comply with the Home Appliance Recycling Law.

In this case, it is preferable to add a resin binder having excellent adhesiveness to the base material serving as a base to the above composition to such an extent that the ease of decomposition is not impaired. The resin to be added may be any resin as long as it has good dispersibility or can be mixed with the polyvinyl acetal resin. For example, a thermoplastic acrylic resin such as polymethyl methacrylate (PMMA), urea resin, nitrocellulose, ester gum, alkyd, cellulose acetate, epoxy, phenol, etc. are used as a solvent drying type, and urethane, acrylic urethane, epoxy are used as a crosslinking reaction type. , Polyester, epoxy polyester and the like. Among these, a thermoplastic acrylic resin and a urea resin having excellent adhesion to a resin material such as plastic are preferable.

The mixing ratio of the binder resin to the polyvinyl acetal resin is 100: 0 to 70 (however, 0 is not included), preferably 100: 0.1, in terms of the mass ratio in terms of the polyvinyl acetal resin and the binder resin, particularly the thermoplastic acrylic resin. ７０70, more preferably 100: 0.5４０40. A binder resin such as an acrylic resin may be used alone, or two or more kinds may be mixed. The mixing ratio in the case of mixing is arbitrary.

天然 Also, natural or synthetic resins known to be biodegradable can be added to the polyvinyl acetal resin within a range that does not impair the adhesion to the composition. These biodegradable resins include starch, starch derivatives, cellulose, cellulose derivatives, chitin, chitosan derivatives, pullulan, curdlan, alginic acid, hyaluronic acid, polysaccharides such as dextran, gluten, casein, collagen, gelatin, fibroin, Polypeptides such as sericin, keratin, casein, polyglutamic acid, polylysine, etc., water-soluble polyesters such as polyhydroxybutyric acid, polyhydroxybutyric acid derivatives, microbial polyesters such as polyhydroxybutyric acid-polyhydroxyvaleric acid copolymer, polyethylene glycol, polyvinyl alcohol, etc. Aliphatic polymers such as polymers, polyglycolic acid, polylactic acid, polyε-caprolactone, polyethylene succinate, polytetramethylene succinate, and copoly (ε-caprolactone / ε-caprolactam) Esters, lacquer, cashew resin, shellac, natural resins such as rosin and the like. These resins may contain a total of 50% by mass or less, particularly 10% by mass or less, based on all components of the composition, depending on the type of the resin.

The easily decomposable resin composition of the present invention can be applied to coating agents, inks, paints, adhesives, films, binders, plating primers and the like by mixing with other additives and auxiliary components as described above. Can be.

In this case, for example, by applying a paint, a primer or the like containing the easily decomposable resin composition of the present invention to a resin base material such as plastic, recycling, a simple treatment such as acid hydrolysis or the like prior to the biodegradation step. The coating film and the base film are decomposed and peeled off, so that the resin substrate and the coating film can be separated very easily. Further, it can be dissolved and desorbed with an environment-compatible mixed solvent such as ethyl alcohol / methylcyclohexane.

The acid used for the acid hydrolysis is not particularly limited, and may be any acid having the acidity required to give + H. Specific examples include hydrochloric acid, sulfuric acid, nitric acid, acetic acid, p-toluenesulfonic acid and the like.

These acids may be used after diluting in a solvent. Examples of the solvent include water and alcohols such as ethanol and methanol.

The mixing ratio of the diacid and the solvent is not particularly limited, and may be adjusted to a required concentration.

The temperature of the treatment liquid is usually about 25 to 80 ° C, and the treatment time is usually about 0.5 to 24 hours, though it depends on the thickness of the coating film.

Using a batch-type tabletop sand mill (vertical), n-butanol was added to 32 g of an alkylacetalized polyvinyl alcohol (trade name: Denkabutyral # 2000-L, manufactured by Denki Kagaku Kogyo KK) having the following structure in a stainless steel vessel of 1 l. A mixed solvent of 96 g / butyl cellosolve / cyclohexanone / butyl acetate (10: 30: 10: 50 volume ratio) was added, and a stirring blade was set, followed by stirring at low speed for 20 minutes. Thereafter, 15 g of a urea resin (trade name: Uban 11HV, manufactured by Mitsui Chemicals, Inc.) was added, and the mixture was further stirred for 15 minutes. After stirring, the stirring blade was removed, and the mixed solution obtained by filtration was used as a coating agent stock solution.

(4) An ABS resin piece (50 mm × 150 mm × 1 mm, manufactured by Ube Sicon) was prepared as an object to be coated, and degreased and washed with n-heptane. Thereafter, the above coating agent stock solution was double-diluted with a mixed solvent of butyl acetate / ethyl acetate / isopropyl alcohol / cyclohexane / cyclohexanone (30: 20: 15: 20: 15 by volume), and this solution was spray-coated, followed by spray coating. Dried for 1 hour at ° C.

次 The primary adhesion of the dried coating film was 100/100 as a result of a grid test (JIS K5400).

  In Example 1, 15 g of a phenol resin (trade name PL-2211, manufactured by Gunei Chemical Co., Ltd.) was used instead of 15 g of a urea resin (trade name: Uban 11HV, manufactured by Mitsui Chemicals, Inc.). Otherwise, a coating agent stock solution was prepared, applied and dried in the same manner as in Example 1.

次 The primary adhesion of the dried coating film was 100/100 as a result of a grid test (JIS K5400).

３６In Example 1, 36 g of an ethylene / vinyl acetate copolymer (polysol EVA @ P-3, manufactured by Showa Polymer Co., Ltd.) was used instead of 15 g of the urea resin. Otherwise, a coating agent stock solution was prepared in the same manner as in Example 1, applied to a resin piece, and dried.

次 The primary adhesion of the dried coating film was 100/100 as a result of a grid test (JIS K5400).

に お い て In Example 1, 12 g of ketone resin (trade name K-90, manufactured by Arakawa Chemical Industry Co., Ltd.) was used instead of 15 g of urea resin. Otherwise, a coating agent stock solution was prepared in the same manner as in Example 1, applied to a resin piece, and dried.

次 The primary adhesion of the dried coating film was 100/100 as a result of a grid test (JIS K5400).

[Comparative Example 1]
A coating agent stock solution was prepared in the same manner as in Example 1 except that 15 g of the urea resin was not used.

A polycarbonate resin piece (50 mm × 150 mm × 2 mm, manufactured by Takiron Co., Ltd.) was prepared as an object to be coated, degreased and washed with n-heptane, and the above coating agent stock solution was washed with butyl acetate / isopropyl alcohol / cyclohexanone / methyl ethyl ketone. A solution diluted twice with a mixed solvent of / xylene / toluene (15: 10: 10: 20: 15: 30) was spray-applied, and dried at 60 ° C for 1 hour.

次 The primary adhesion of the dried coating film was 90/100 as a result of a grid test (JIS K5400).

(4) The dried coating film could be easily dissolved and desorbed with an environment-compatible mixed solvent such as ethyl alcohol / methylcyclohexane (70:30).

に お い て In Example 1, 20 g of a thermoplastic acrylic resin (trade name: Dianal LR-158, manufactured by Mitsubishi Rayon Co., Ltd.) was used instead of 15 g of the urea resin, and the mixture was stirred for 15 minutes. After stirring, the stirring blade was removed and replaced with a dispersion disk (13 pieces with a diameter of 70 mm), the same amount of glass beads was added to the above mixed solution, and the mixture was dispersed at medium speed for 30 minutes. Further, the mixed solution obtained by filtering and removing the glass peas was used as a coating agent stock solution.

(4) As an object to be coated, the same ABS resin piece as in Example 1 was prepared, sprayed and dried in the same manner as in Example 1.

次 The primary adhesion of the dried coating film was 100/100 as a result of a grid test (JIS K5400).

In the same manner as in Example 1, except that 20 g of [Dianal LR-574 (trade name) manufactured by Mitsubishi Rayon Co., Ltd.] was used as the thermoplastic acrylic resin instead of 15 g of the urea resin, the coating solution stock solution was used. Got.

Next, it was applied to the object to be coated in the same manner as in Example 5 and dried.

次 The primary adhesion of the dried coating film was 100/100 as a result of a grid test (JIS K5400).

In Example 5, a coating agent stock solution was obtained in the same manner as in Example 1 except that 30 g of [Dianal LR-510, manufactured by Mitsubishi Rayon Co., Ltd.] was used as the thermoplastic acrylic resin instead of 15 g of the urea resin. Was.

Next, it was applied to the object to be coated in the same manner as in Example 5 and dried.

次 The primary adhesion of the dried coating film was 100/100 as a result of a grid test (JIS K5400).

In Example 7, a polycarbonate resin piece (50 mm × 150 mm × 2 mm, manufactured by Takiron Co., Ltd.) was prepared as an object to be coated, degreased and washed with n-heptane, and the coating agent stock solution was treated with butyl acetate / isopropyl alcohol. A solution diluted twice with a mixed solvent of / cyclohexanone / methyl ethyl ketone / xylene / toluene (15: 10: 10: 20: 15: 30 by volume) was spray-coated, and dried at 60 ° C. for 1 hour.

次 The primary adhesion of the dried coating film was 100/100 as a result of a grid test (JIS K5400).

(4) The dried coating film could be easily dissolved and desorbed with an environment-compatible mixed solvent such as ethyl alcohol / methylcyclohexane (80:20 volume ratio).

コ ー テ ィ ン グ A coating agent stock solution was obtained in the same manner as in Example 5 except that 28 g of an alkylacetalized polyvinyl alcohol (trade name: Denkabutyral 3000-2) was used instead of 32 g of the alkylacetalized polyvinyl alcohol.

と し て A polycarbonate resin piece (50 mm × 150 mm × 2 mm, manufactured by Takiron Co., Ltd.) was prepared as an object to be coated, and degreased and washed with n-heptane. Thereafter, the above coating agent stock solution was diluted twice with a mixed solvent of butyl acetate / isopropyl alcohol / cyclohexanone / methyl ethyl ketone / xylene / toluene (15: 10: 10: 20: 15: 30 by volume), and this solution was spray-coated. And dried at 60 ° C. for 1 hour.

次 The primary adhesion of the dried coating film was 100/100 as a result of a grid test (JIS K5400).

(4) The dried coating film could be easily dissolved and desorbed with an environment-compatible mixed solvent such as ethyl alcohol / methylcyclohexane (80:20).

"Hydrochloric acid hydrolysis of alkyl acetalized polyvinyl alcohol trade name Denka Butyral 2000-L"
12N hydrochloric acid was diluted twice with methanol to obtain a 6N hydrochloric acid / methanol solution. 500 mg of denkabutyral 2000-L was dissolved in 20 ml of this solution, and the mixture was heated to reflux at 80 ° C. Sampled after 2 and 24 hours, hydrochloric acid was removed by concentrating the solution. FIG. 1 shows the result of comparing the IR spectrum of the obtained residue with the IR spectrum of polyvinyl alcohol (polymerization degree 1500, Wako Pure Chemical Industries, Ltd.).

As is clear from FIG. 1, as the treatment time becomes longer, the absorption derived from C—O—C near 900 to 1000 cm ⁻¹ disappears, and a similarity to the spectrum of polyvinyl alcohol was confirmed. Therefore, generation of polyvinyl alcohol over time by acid hydrolysis of polyacetal was strongly suggested.

(4) The coating agent stock solution in Comparative Example 1 was dropped into a 28 mm diameter polypropylene cap so that the final dry weight was 40 to 45 mg, and dried at 60 ° C. for 30 minutes to prepare a polyvinyl acetal film.

Similarly, the coating agent stock solution in Example 8 was dropped into a 28 mm diameter polypropylene cap so that the final dry weight was 40 to 45 mg, dried at 60 ° C. for 30 minutes, and mixed with a polyvinyl acetal / thermoplastic acrylic resin mixed film. Was adjusted.

A 6N hydrochloric acid solution was adjusted with 10 ml of a 10% methanol solution, and the above films were immersed three by three. After standing at room temperature for 24 hours, the eluted components were concentrated and the proton NMR spectrum was measured. The results are shown in FIGS. FIGS. 4 and 5 show proton NMR spectra of denkabutyral 2000-L and PVA 1500 as comparative samples, respectively.

As a result, spectra similar to polyvinyl alcohol were observed in both samples, and the formation of water-soluble polyvinyl alcohol by acid hydrolysis of polyvinyl acetal was confirmed.

It is the figure which performed the acid-hydrolysis process for 0 hour, 2 hours, and 24 hours of Example 10, and the figure which showed the IR spectrum of polyvinyl alcohol. FIG. 11 is a proton NMR spectrum of the residue after treatment with denkabutyral 2000-L in 6N @HCl for 24 hours in Example 11. FIG. 11 is a proton NMR spectrum diagram of the residue after treatment of denkabutyral 2000-L + LR-510 in Example 11 with 6N HCl for 24 hours. It is a proton NMR spectrum figure of Denka Butyral 2000-L. It is a proton NMR spectrum figure of PVA1500.

Claims (6)

A method for treating an easily decomposable polymer resin in which a polyvinyl acetal resin is acid-hydrolyzed and at least a part thereof is converted into polyvinyl alcohol. Containing easily degradable polymer resin and binder resin,
A method for treating an easily decomposable resin composition, wherein the easily decomposable polymer resin is a polyvinyl acetal resin,
A method for treating an easily decomposable polymer, wherein the polyvinyl acetal resin is subjected to acid hydrolysis to convert at least a part of the resin into polyvinyl alcohol. The binder resin is a thermoplastic acrylic resin,
3. The easily decomposable polymer according to claim 2, wherein the easily decomposable polymer resin and the binder resin are contained in a mass ratio of polyvinyl acetal resin to thermoplastic acrylic resin of 100: 0 to 70 (excluding 0). A method for treating a resin composition. The method according to claim 2 or 3, wherein the thermoplastic acrylic resin is a homopolymer. The method for treating an easily decomposable resin composition according to any one of claims 2 to 4, wherein the easily decomposable resin composition is a coating film of a plastic resin or a primer material. The method for treating an easily decomposable resin composition according to any one of claims 2 to 5, wherein the easily decomposable resin composition further contains a chitosan derivative.

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