JPS62117668A - Method for removing cured coated film - Google Patents

Abstract

PURPOSE:To remove an unnecessary coated film and to regenerate an article with comparatively simple operation by dipping the article having an organopolysiloxane cured coated film in an aq. alkaline soln. CONSTITUTION:The unnecessary cured coated films deposited on various molded articles are removed, the articles are reutilized, and resources are effectively utilized by this method. The organopolysiloxane cured coated film obtained from a composition contg. an organosilicon compd. shown by the general formula, R<1>aR<2>bSI(OR<3>)4-a-b [where R<1> and R<2> are alkyl, alkenyl, etc., R<3> is 1-8C alkyl, alkoxyl, etc., and (a) and (b) are 0 or 1], and/or the hydrolysate of the compd. is dipped in an aq. alkaline soln. of sodium hydroxide, etc. Consequently, the article can be easily regenerated and repeatedly used without damaging the article.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for removing unnecessary hardened coatings attached to various molded products. In other words, it concerns the best use of goods, or in other words, the best use of resources.

[Prior Art] Metal articles or plastic molded articles are used for many purposes, taking advantage of their high heat resistance, Fg chemical resistance, mechanical strength, easy workability, and durability. Various surface treatments have been attempted for the purpose of further functionalizing articles that exhibit the characteristics 1). Taking advantage of the above-mentioned advantages, it is often used as a holding and curing tool during various types of metal and physical crystal processing.

However, metal articles are generally expensive, and 7JI I
Recycling in the event of a mistake or reuse in the event of use as an overnight stay is a difficult task from the standpoint of reducing rice costs and making efficient use of resources. Also, for plastic molded products, if a processing mistake is made to improve the surface hardness, etc., recycling is possible.
This is an important issue in terms of reducing labor costs.

Conventionally, attempts have been made to physically remove the hardened film using sandpaper or the like.

[Problems to be solved by the invention] Physical removal using lint paper or the like is difficult to apply to objects with complex shapes, and not only is the removal not complete, but it also causes 10 scratches on metal objects. There's a problem. Furthermore, there is a problem in that the J3 plastic molded product has significant scratches, making it virtually impossible to reuse it.

1. Means for Solving Problems] The present inventors have proposed solutions and improvements to these problems.
As a result of extensive efforts, we have arrived at the present invention as described below. '-,'j''aThe present invention is a method for removing a hardened film, which is characterized by immersing an article coated with an alkaline hardened film in an alkaline aqueous solution.

A Kanoborishi [1. Kirin-based hardened coating] according to the present invention. There are coatings that are two-dimensionally crosslinked by heat, active energy ray irradiation, etc. Particularly effective in the present invention is a cured coating obtained from a composition containing at least the above-mentioned component A.

A, compound J represented by the following general formula (1)
3 and 2·′ or their hydrolysates.

a nyl group, an aryl group, a glycidoxy group, an epoquine group, an amine group, a mercapto group, a (meth)acryloxy group, or a hydrocarbon group having t or cyano, R3 has 1 to 1 carbon atoms; 8)' is a l group, an alkoxyalkyl group, an acyl group, a phenyl group, an arylalkyl group, and aJ3 and b are O or 1).

Specific representative examples of the organosilicon compound represented by the general formula (1) include methyl silicate, edyl silicate, n-propyl silicate, macropropyl silicate-1, robyl silicate-1 to 5eC-butyl silicate, dobutyl silicate, Tetraacetoxysilane, methyltrimethoxysilane, methyl 1-1-1 hexysilane, methyltrimethoxyethoxysilane, methyl 1-rimethoxysilane, methyl 1-11-xysilane, methyltrimethoxysilane, methyltri)7miloxysilane,
Methyltrimethoxysilane, Methyltribenzyloxysilane, Methyl 1 ~ Rif ■ Nedyloxysilane, Glycidoxymethyl 1 - Helimethoxysilane, Glycidoxymethyl 1 ~ Lithoxysilane, α-Glycidoxy ethyl trimy~xysilane , α-glycidoxyethyltriethoxysilane, β-glycidoxyethyltrimethoxysilane, β-glycidoxyethyltriethoxysilane, α-
Glycidoxypropyl 1 ~ Rime 1 ~ Xysilane, α-Glycidoxy 10 Pyl 1 ~ Liethoxysilane, β-Glycidoxysilane]] Building 1 Herimethoxysilane, β-Glycidoxypropyltriethoxysilane, γ ~ Crysitoxypropyl Trimethoxysilane, γ-glycidoxypropyl 1-liethoxysilane, T-glycidoxypropyl 1-helipropoxysilane, γ-glycidoxypropyl 1-ributoxysilane, γ-glycidoxypropyltrimethoxyethoxysilane , γ-glycidoxypropyltriphenoxysilane, α-glycidoxybutyltrimethoxysilane, α-glycidoxybutyl 1-ethoxysilane,
β-glycidoxybutyltrimethoxysilane, β-glycidoxybutyltriethoxysilane, γ~crisitoxybutyltrimethoxysilane, γ-glycidoxybutyl 1
~Liethoxysilane, δ-glycidoxybutyl 1-helimethoxysilane, δ-glycidoxybutyl 1-liethoxysilane, (3,4-epoxycyclohexyl)methyl 1-rimethoxysilane, (3,4-epoxycyclohexyl) For Mebu-Rie 1-Xysilane, β-(3,4-
Epoxycyclohexyl) ethyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyl 1-lipropoxysilane, β-(3,4-epoxycyclohexyl) Ethyltributoxysilane, β
-(3,4-epoxycyclohexyl>ethyltrimethoxyethoxysilane, β-(3,4-epoxycyclohexyl)ethyltriphenoxysilane, γ-(3,4-
Epoxycyclohexyl)propyl 1-rimethoxysilane, γ-(3,4-epoxycyclohexyl)propyltriethoxysilane, β-(3,4-epoxycyclohexyl)butyl helimethoxysilane, β-(3,4-
epoxycyclohexyl)butyltriethoxysilane,
Glycidoxymethylmethyllame 1-xysilane, glycidoxymethylmethyldiethoxysilane, α-glycidoxyethylmethyldimethoxysilane, α-glycidoxyethylmethyljethoxysilane, β-glycidoxyethylmethyldimethoxysilane, β-glycidoxyedylmethyldiethoxysilane, α-glycidoxypropylmethyldimethoxysilane, α-glycidoxypropylmethyldimethoxysilane, α-glycidoxypropylmethyldimethoxysilane, methyldiIt-1”disilane, β-glycidoxypropylmethyldit-Vdisilane, T- Glycidoxypropylmethyldimethoxysilane, T~glycidoxypylmethyldi[toxysilane, γ-glycitoxypropylmethyldiproboxysilane, γ~glycidoxypropylmethyldibutoxysilane, γ-glycidoxypropylmethyldimethoxy Ethoxysilane, γ-glycidoxybrobylmethyldinoenoxysilane, γ-glycidoxypropylethyldimethoxysilane, γ-glycidoxypropylethyldiT1-xysilane, γ-glycidoxypropylbylvinyldimethoxysilane , γ-glycidoxyp[]pyruvinyljethoxysilane, γ-glycidoxypropylphenyldimethoxysilane, T-glycitoxypropylphenyldiethoxysilane, ethyltrimethoxysilane,
Ethyltriethoxysilane, vinyltrimethoxysilane, vinylcyto 1 unit] - xysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, γ-9 day propyl Trimethoxysilane, γ-talolopropyltriethoxysilane, γ-chloropropyltriacetoxysilane, 3
, 3゜3-trifluoropropyltrimethoxysilane, T
- MEC 1 noroxypropyltrimethoxysilane, γ
-Mercaptopropyl-mercaptopropyltriethoxysilane, β-cyanoethyltriethoxysilane, chloromethyltriethoxysilane, chloromethyltriethoxysilane, N13-aminoethyl)γ-aminopropyl 1-helimethoxysilane, N-(β-7minoethyl)γ -aminopropylmebrdimethoxysilane, γ-aminopropyltrimethoxysilane, γ-7minopropylmethyldimethoxysilane,
N-(β-7minoethyl)γ-aminopropyltrie 1
Hexysilane, N-(β-aminoethyl)γ-aminopropylmethyldie-1-oxysilane, dimethyldimethoxysilane, phenylmethyldimethoxysilane, dimethyldimethoxysilane, phenylmethyldimethoxysilane, T
-ri[10but[1 pylmethyldimethoxysilane, γ-chloro[1propylmethyldiethoxysilane, dimethyldi?
T? l”xysilane, γ-methacrylicoxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-mercaptopropylmethyldimethoxysilane, T-mercaptopropylmethyljethoxysilane, methylhinyldime-1hexysilane, methylvinyl Examples include die 1 to xysilane.

It is fully possible to use not only one type of these organosilicon compounds but also two or more types (if used).

There is no problem even if the following compounds are added to the cured film of the present invention for the purpose of improving dyeability. Compounds that can be added include hisphenol type epoxy resin, hisphenol ¥1 epoxy fat 1 fat, fat I
M, various epoxy resins such as epoxy resins, brominated epoxy resins, glycidyl ester type epoxy resins, Ebibis type epoxy resins, notaric acid glycidyl ester type epoxy 1-shell resins, polyvinyl butyral, polyvinyl alcohol, celluloses, melamine resins, Examples include acrylic resin and Bois urethane resin.

Further, there is no problem even if particulate inorganic substances, which are generally used for the purpose of improving surface hardness, are added to the cured film of the present invention. Here, the fine particulate inorganic substance has an average particle diameter of about 1 to 300 mμ, preferably about 5 to 200 mμ.
are often used.

Examples of these particulate inorganic substances include particulates such as silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, tin oxide, and antimony oxide.

There is no problem in the present invention even if these cured films are mixed with various curing agents for the purpose of accelerating curing, enabling low-temperature curing, etc. when they are formed. Commonly used curing agents include various epoxy resin curing agents and various organosilicon resin curing agents.

Specific examples of these curing agents include various acids and their acid anhydrides, nitrogen-containing organic compounds, various metal complex compounds or metal alkoxides, and organic carbophosphates of alkali metals. Examples include various salts such as carbonates.

The method of coating the cured organopolysiloxane film according to J3 of the present invention is usually carried out by coating the composition as a precursor of the cured product with a liquid composition in the presence of a solvent or in the absence of a solvent. The coating means is not particularly limited, and any method may be used without any problem.

On the other hand, the article referred to in the present invention is not particularly limited as long as it is necessary for the present invention.
Oxidation resistance ↑1-1 Metals, especially stainless steel, are suitable from the viewpoint of heat resistance and mechanical strength. Other heat-resistant plastics such as fluororesin, silicone resin, and polyimide may also be used. Furthermore, it is preferably applied to various plastic molded products, especially polymethyl methacrylate, polycarbonate, diethylene glycol bisallyl carbonate hand-combined products, and the like.

In the present invention, the article having the above-mentioned cured film is immersed in an alkaline aqueous solution. Specific examples of usable alkali sources include lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, and ammonia. Can be mentioned. Alkali metal hydroxide salts are particularly preferably used from the viewpoint of alkali strength and odor. In addition, the C degree of the alkaline aqueous solution is not particularly limited, but it can shorten the processing time,
From the viewpoint of extending the life of the processing solution, a maximum percentage of 2 to 40% is preferably applied. The soaking time and soaking temperature (:) are experimentally determined depending on the type of cured film, film 19, etc., but usually it is 5 minutes to 48 hours, 5°C to 90°C.
It is done in C.

There are various types of products to which the present invention can be applied. However, it is suitable for molded products.

[Example] Example 1 (1) Preparation of silane hydrolyzate 236 g of γ-glycidoxyprobyltrimethoxysilane
The mixture was cooled to 10° C., and 54 q of 0.01N hydrochloric acid aqueous solution was gradually added dropwise while stirring. After the addition, stirring was continued for an additional hour at room temperature to obtain one digit of silane hydrolyzate.

(2) Preparation of coating agent Ethyl)norkol 266.
8C], silicone surfactants o and aq were added and mixed, aluminum acetylacemylate 5 and ○q were added, and after thorough stirring, a "-tinging agent" was prepared.

(3) Applying and curing the coating agent After infiltrating the hand-coupled lens into the diethylene glycol bisallyl carbonate 1 set in the buing shell, take it out and remove the metal in the coating agent solution. It was heated at 93°C for 14 hours in a stone state.

(4) Regeneration] The coating jig and lens heated with the coating agent attached were immersed in an alkaline aqueous solution under the conditions shown in Table 1. The results are shown in Table 1. As a comparative example, it was immersed in water that did not contain alkali, but no regeneration was possible.

1. Effects of the Invention] The method for removing a cured film obtained by the present invention has the following effects.

(1) Regeneration processing can be performed with relatively less than two operations in the cylinder.

(2) Can be recycled without being affected by the shape of the item.

(3) Since deposits can be removed without damaging the article, repeated use is possible.

Claims (4)

[Claims] (1) A method for removing a cured film of an article having an organopolysiloxane cured film, which comprises immersing the article in an alkaline aqueous solution. (2) The method for removing a cured film according to claim (1), wherein the organopolysiloxane cured film is a cured film of a composition containing at least component A below. A, an organosilicon compound represented by the following general formula (I) and/or a hydrolyzate thereof. R^1_aR^2_bSi(OR^3)_4_-_a_
-_b(I) (where R^1 and R^2 are each an alkyl group, an alkenyl group, an aryl group, or a halogen group,
A hydrocarbon group having a glycidoxy group, an epoxy group, an amino group, a mercapto group, a (meth)acryloxy group, or a cyano group, R^3 is an alkyl group having 1 to 8 carbon atoms, an alkoxyalkyl group, an acyl group, a phenyl group , an arylalkyl group, and a and b are 0 or 1). (3) The method for removing a cured film according to claim (1), wherein the aqueous alkali solution is an aqueous solution of an alkali metal hydroxide salt. (4) The method for removing a cured film according to claim (1), wherein the article is metal or plastic.