JPH059419A - Agent and process for releasing and removing coating resin film - Google Patents

Abstract

PURPOSE:To provide an agent for releasing and removing a coating resin film which has a performance of effectively removing a coating film, good workability and high environmental safety, and a process for releasing and removing a coating resin film. CONSTITUTION:An agent for releasing and removing a coating resin film comprising 10-90wt.% compound A having an unsaturation between a carbon atom and an atom of a different kind, such as an aprotic solvent, an imide or a ketone, and 10-90wt.% compound B comprising an at least monohydric alcohol having a boiling point of 250 deg.C or below and being normally liquid or its derivative. This agent is sprayed onto or applied to a coated part at 50-150 deg.C or this part is immersed in the agent to release and remove the resin film from the part.

Description

Detailed Description of the Invention

[0001]

[Industrial application] Coating removal agents and coating removal for resin parts that have effective coating removal performance, good workability, and high environmental safety in resin coating processing or pretreatment of recycled materials. Law is required. The present invention relates to a resin film peeling and removing agent that does not cause ozone layer destruction and the like and is excellent in handleability, and a resin coating film peeling and removing method using the peeling and removing agent.

[0002]

2. Description of the Related Art As conventional stripping agents for resin coatings, chloropentafluoropropane / 1,1 dichloro-1-trifluoroethane mixed solvent composition (JP-A-2-286795) and chloropentafluoropropane / A mixed solvent composition of dichlorotrifluoroethane (JP-A-2-286796) is proposed. In addition, the inventors have already disclosed a resin coating peeling remover composition liquid and a removing method (Japanese Patent Application No. 3-8300).
No. 9) presented a solvent or solution composition that can physically or chemically remove the coating film. Further, a normal halogen-based solvent such as methylene chloride, a strong alkaline solution, or a strong acid solution is well known.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The mixed solvent composition disclosed in JP-A No. 2-286796 and JP-A No. 2-286796 has the characteristics that it is excellent in detergency against fats and oils and has a low risk of depleting the ozone layer. However, since the molecular chain contains a large number of halogen atoms (F, C1), there are problems such as being careful in handling in terms of environmental hygiene. In addition, there is a problem that use of a normal halogen-based solvent deteriorates environmental hygiene and, at the same time, causes ozone layer depletion. Even when a strong alkaline solution or a strong acid solution is used, there are problems in work safety and environmental safety, and there are complications such as the necessity of a post-treatment step such as neutralization. Further, in some of the mixed solvent compositions described in the above-mentioned Japanese Patent Application No. 3-83009, the primer surface made of chlorinated polyolefin or the like was not sufficiently peeled off depending on the composition of the coating resin.
When kneading or the like is performed using a material whose peeling of the primer surface is insufficient, there is a problem such as causing corrosion on the contact surface of the processing equipment.

The present invention has been made by paying attention to such a conventional problem, and 10 to 90% of a compound A having an unsaturated bond between different atoms such as an aprotic solvent or imines or ketones is used. % By weight, preferably 20-80% by weight
And a compound B consisting of a monohydric or higher alcohol or its derivative, which has a boiling point of 250 ° C. or lower and is in a liquid state at room temperature.
Of 10 to 90% by weight, preferably 20 to 80% by weight, is applied to the resin-coated resin parts at a temperature of 50 ° C to 150 ° C, preferably 50 to 100 ° C. The above-mentioned problems are solved by immersing the above-mentioned resin component in.

The resin coating film peeling / removing agent of the present invention contains 10 to 90% by weight, preferably 20 to 80% by weight of an aprotic solvent or a compound A having an unsaturated bond between different atoms such as imines or ketones. 10 to 90% by weight, preferably 20 to 90% by weight, of the compound B composed of a monohydric or higher alcohol or its derivative, which is in a liquid state at room temperature with a boiling point of 250 ° C or less.
It is characterized by comprising 80% by weight.

Is an aprotic solvent of the above compound A having an unsaturated bond between the above-mentioned heteroatoms:

[Chemical 1] [Wherein R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents an NH ₂ group or an N (CH ₃ ) ₂ group] and the following formula

[Chemical 2] [Wherein R ₃ is -C ₃ H ₆ -N (CH ₃ )-or -C ₃ H ₆ -NH- or -N (CH ₃ ) -C ₂ H ₄ -N (CH ₃ )-or , -N (CH ₃ ) -C ₂ H ₄ -N (C
H ₃ )-], represented by the following formula

[Chemical 3] Sulfoxides represented by the formula [R ₄ and R ₅ in the formula are C _n H 2 _{n + 1} (n = 1 to 4)] are used.

These aprotic solvents include formamide, N, N-dimethylformamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone,
Dimethyl sulfoxide and the like are preferably used. Further, as the ketones of the above compound A, the following formula

[Chemical 4] [Wherein R ₆ and R ₇ in the formula represent C _n H _{2n + 1} (n = 1 to 10) or an aromatic group],
Of these, methyl ethyl ketone and the like are preferably used. Further, as the imine of the compound A, an imine represented by R ₈ —N═C═N—R ₉ (R ₈ and R ₉ in the formula represent C ₆ H ₁₁ ) and the like are used.

Further, as the compound B, monools represented by the following formula R ₁₀ --OH [wherein R ₁₀ represents C _n H 2 _{n + 1} (n = 1 to 10) or an aromatic group] diols represented by the following formula HO-R ₁₁ -OH [R ₁₁ in the formula have _{C n H2 n (n = 1} ~10) or an aromatic group], the formula R ₁₂ -SH wherein R ₁₂ of C _n H2 _{n + 1} (n = 1 to 10) or an aromatic group] is used as the thiol (monothiol).

[0009]

The above-mentioned compound A mainly diffuses / penetrates into the primer resin, swells and swells the primer resin, and separates it. Therefore, when the concentration of the compound A is less than 10% by weight, the primer resin is not sufficiently swollen and expanded,
The paint does not peel off. On the other hand, when the amount of the compound A is more than 90% by weight, the swelling of the coating resin may be insufficient and the coating may not be peeled off. When the resin-coated resin component swells with respect to the coating film peeling remover and the mass change rate is less than 20%, the swelling of the coating resin is insufficient and the coating resin cannot be peeled off. On the other hand, the above-mentioned peeling remover for the resin coating film is the compound B having mono, diol or its derivative.
10 to 90% by weight, preferably 20 to 80% by weight. The compound B mainly diffuses / penetrates the coating resin, swells and expands the coating resin, and promotes the diffusion / permeation of the compound A. Further, since the compound B has hydrophilic and lipophilic groups, it has an effect on the penetration of the above-mentioned coating film peeling / removing agent from the interface of coating resin / primer resin / resin part.

However, when the compound A having a carbon chain length of 10 or more is used, the boiling point exceeds 250 ° C., the viscosity of the liquid increases, the lipophilicity increases, the solubility in water decreases remarkably, and the resin peels off. Since the coating film wettability and diffusion / permeability due to the agent impair the workability in the drying step, etc.
Dodecyl alcohol is not suitable for use. Further, when the compound B is used in an amount of more than 90% by weight, the primer resin cannot be sufficiently swollen and expanded, and the coating resin may not be peeled off.

The above-described resin film peeling and removing agent of the present invention is particularly preferably used for peeling and removing the resin coating film of the acrylic, melamine or urethane resin coating treated resin parts. The peeling removal can be performed by spraying or applying the peeling remover to the resin paint component as described above, or by immersing the resin coated component in the peeling remover.

Next, the present invention will be described with reference to the drawings. FIG. 1 is a view showing a cross section of a resin coated component. From the painted surface side,
The coating resin layer 1, then the primer resin layer 2 and the resin base material 3 as the lowermost layer. Using the resin film peeling removal agent and peeling removal method of the present invention, from the resin coated parts,
Fig. 2 (a) shows three types of peeling mechanism for peeling and removing the coating.
Shown in (b) and (c). FIG. 2A shows that the coating resin layer 1 swells and swells remarkably as compared with the primer resin layer 2 due to the action of the compound B, and peels off at the interface vicinity 4 of the coating resin layer 1 / primer resin layer 2. On the contrary, in FIG. 2 (b), the primer resin 2 is significantly swollen and expanded as compared with the coating resin layer 1 mainly due to the action of the compound A, and thus the coating resin layer 1 / primer resin layer 2 or the primer resin layer 2 / resin It shows that peeling occurs near the interface 4 of the base material 3. Next, in FIG. 2 (c), the coating resin layer 1 and the primer resin layer 2 swell due to the action of both the compounds A and B, and the swelling of the primer layer 2 having a low degree of curing progresses remarkably and the primer resin layer 2 2 shows that peeling occurs at the vicinity 4 of the interface of the resin base material 3.

2 (a), 2 (b) and 2 (c), when either the coating resin layer 1 or the primer resin layer 2 swells to a swelling degree (ΔWs) of 20% by weight or more. Paint peeling is observed. In addition, the swelling or swelling of the resin base material 3 is not recognized at all in the above-mentioned coating peeling. The degree of swelling (ΔWs) is defined as follows. ΔWs (%) = 100 (Ws−Wo) / Wo Wo: Swelling by the paint remover, coating resin layer 1 before expansion
Alternatively, the weight of the primer resin layer 2 Ws: swelling by the paint removal agent, after swelling (temperature: 50 to 1
Weight of coating resin layer 1 or primer resin layer 2 at 50 ℃, processing time: 15 minutes)

Next, the use temperature of the stripping and removing agent for the resin coating film is 50 to 150 ° C, preferably 60 to 100 ° C. Five
At a use temperature lower than 0 ° C., the peeling / removing agent does not diffuse / permeate into the coating resin and the primer resin sufficiently quickly, so that the coating resin and the primer resin do not peel in a practical time. On the other hand, if the temperature is higher than 150 ° C, melting, heat deterioration and oxidative deterioration of the resin component body will occur. In the method for peeling and removing the resin coating film of the present invention, the treatment method using the peeling and removing agent is, from an industrial viewpoint, immersing the resin component in the peeling and removing agent, or in the vapor of the peeling and removing agent, the resin. This can be done by exposing the parts.

[0015]

EXAMPLES The present invention will be described below with reference to examples and comparative examples. Preparation Example of Peeling Remover for Resin Coatings At room temperature, the above compounds A (liquid) and B (liquid) were poured into respective beakers and weighed with an automatic balance to a predetermined weight. After mixing the two liquids, a magnetic stirrer and stirring were performed. A peeling remover for the resin coating film was prepared by stirring with a child.

The results of the coating film peeling removal evaluations in Tables 1 and 2 show specific preparation examples of the coating film peeling remover. Incidentally, industrially, it is possible to prepare the resin coating decomposition remover by utilizing the densities of the compounds A and B and weighing the volume in terms of weight.

Test Example for Degradation and Removal of Resin Coating Film Next, an appropriate amount (about 100 ml) of the above-described resin coating peeling and removing agent was placed in a round-bottomed flask with a magnetic stirrer stirrer.
Reflux was carried out until the temperature reached the set temperature (50/150 ° C). After holding the peeling remover at the set temperature, 5 pieces of the cut pieces of about 10 mm in width × about 10 mm in length × about 2 mm in thickness cut out from the resin part treated with the resin coating are put into the flask to be the decomposition removing agent. It was immersed, left for 30 minutes and observed. Then, the split pieces were taken out from the flask, and the state of decomposition and removal of the resin coating was visually determined.

In the coating peeling removal evaluation of Table 1 and Table 2,
A specific evaluation test example was shown. The types of resin coating resin used in the evaluation test are two types (I, II).
The coating resin and primer resin have different chemical compositions. Table 1,
In Table 2, after the evaluation test, when a change was observed in the coating resin and the primer resin, when the primer resin was decomposed or swelled and peeled off, ∘, and when the coating resin was decomposed or swelled and peeled, ◯, one When partial dissolution or decomposition or swelling and peeling were observed, Δ mark was shown, and when no change was observed, the number of changed was shown in the mark of X mark (5 test samples were used respectively).

Example 1 About 100 ml of a stripping and removing agent for resin coating (N, N-dimethylformamide / ethanol = 10% by weight / 90% by weight) was added to 200 m.
Transfer to a l-shaped eggplant-shaped flask, stir on a water bath using a magnetic stirrer, and stir at the specified temperature (50 ℃, 80
The mixture was refluxed until the temperature reached ℃ or 100 ℃. Next, split pieces (horizontal x vertical x thickness = 10 x 10 x) of resin coated parts (painted items I and II)
Five pieces each of 2 mm) were cut out, immersed in the resin coating film peeling remover liquid in the flask, and treated for 30 minutes. Then, the contents of the flask were taken out into a beaker, and the resin coating of the split pieces and the degree of decomposition of the primer resin were visually confirmed. The obtained results are as shown in Table 1. Examples 2 to 31, Comparative Examples 1 to 14 The peeling and removing agents for the resin coatings of Examples 2 to 31 shown in Table 1 and Comparative Examples 1 to 14 shown in Table 2 are used, and the predetermined temperatures are shown in Table 1. Except for the temperature (water bath or oil bath heating), the split pieces of the resin-coated parts were treated in the same manner as in Example 1, and the peeling state of the coating resin and primer resin of each split piece was visually confirmed. did. The obtained results are as shown in Tables 1 and 2.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

As described above, the resin peeling decomposition removing agent of the present invention has the compound A having a concentration of 10 to 90% by weight.
And 10 to 90% by weight of Compound B,
Deterioration of environmental hygiene by spraying or applying the exfoliation remover to resin coating treated resin parts, dipping / applying to the decomposition remover, or exposing to the vapor of the remover at a temperature of 50 to 150 ° C. By doing so, it is possible to obtain an effect that the resin coating film can be decomposed and removed efficiently and successfully without causing ozone layer destruction. Further, since the primer surface is also removed at the same time, when kneading or the like using these materials, the corrosion of the contact surface of the processing equipment is prevented.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a resin-coated resin component.

FIG. 2 (a) is an explanatory view showing a state in which a coating film of a resin coating treated resin part is peeled off by a peeling remover for a resin coating film of an example of the present invention, and (b) a coating film of a resin coating treated resin part. It is an explanatory view showing a state of peeling by a peeling remover of the resin coating film of another example of the present invention, (c) peeling of the coating film of the resin coating treated resin component of the resin coating film of another example of the present invention It is explanatory drawing which shows the state peeled by the remover.

[Explanation of symbols]

1 Coating resin layer 2 Primer resin layer 3 resin base material 4 Coating film peeling part

Claims (3)

[Claims] 1. An aprotic solvent, or 10 to 90% by weight of a compound A having an unsaturated bond between different atoms such as imines or ketones, and a liquid state at room temperature having a boiling point of 250 ° C. or lower, A peeling remover for a resin coating film, which comprises 10 to 90% by weight of a compound B consisting of a monohydric or higher alcohol or its derivative. 2. A compound A for acrylic, melamine or urethane resin coating at a temperature of 50 to 150.degree.
The swelling ratio (ΔWs) is 20% or more when swollen with a resin film stripping and removing agent consisting of a mixed solution of the compound B and the compound B. 3. A method for peeling and removing the resin coating film according to claim 1 at 50 to 150.degree.
Alternatively, a method for peeling and removing a resin coating film, which comprises immersing a resin coated part in the above-mentioned resin film peeling and removing agent.