JP2924323B2 - Removal agent and method for removing resin film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION Paint removal agent and paint removal for resin parts with effective paint removal performance, good workability, and high environmental safety in the resin coating processing process or the pretreatment process for recycled materials. Law is required. The present invention relates to a stripping / removing agent for a resin coating which does not cause destruction of the ozone layer and is excellent in handleability, and a method for stripping / removing a resin coating using the stripping / removing agent.

[0002]

2. Description of the Related Art Conventional stripping agents for resin coatings include chloropentafluoropropane / 1,1-dichloro-1-trifluoroethane mixed solvent composition (JP-A-2-286795) and chloropentafluoropropane / solvent. A dichlorotrifluoroethane mixed solvent composition (JP-A-2-286796) and the like have been proposed. In addition, the inventors have already prepared a resin coating stripping / removing agent composition solution and a removing method (Japanese Patent Application No. 3-8300).
No. 9) presented a solvent or solution composition capable of physically or chemically stripping the coating. Further, ordinary halogen solvents such as methylene chloride, strong alkaline solutions or strong acid solutions are well known.

[0003]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 2-286795.
The mixed solvent compositions disclosed in Japanese Patent Application Laid-Open Nos. 2-286796 and 2002-286796 are excellent in detergency against oils and fats and have a low risk of destruction of the ozone layer. And the use of a large number of halogen atoms (F, C1) in the molecular chain, there is a problem that attention must be paid to handling in terms of environmental hygiene. In addition, there is a problem that the use of a normal halogen-based solvent deteriorates environmental hygiene and also causes ozone layer destruction. Even in the use of a strong alkaline solution or a strong acid solution, there are problems such as work safety and environmental safety, as well as complication that a post-treatment step such as neutralization is essential. Further, in the mixed solvent composition described in the specification of Japanese Patent Application No. 3-83009, the peeling of the primer surface made of chlorinated polyolefin or the like was insufficient depending on the composition of the coating resin.
When kneading or the like is performed using a material with insufficient primer surface peeling, there is a problem that corrosion occurs on the contact surface of the processing equipment.

The present invention has been made in view of such a conventional problem, and 10-90% by weight, preferably 20-80% by weight of 1,3-dimethyl-2-imidazolidinone and a boiling point of 1,3-dimethyl-2-imidazolidinone. Compound B consisting of monools, diols or thiols, which is in a liquid state at a normal temperature of 250 ° C. or less,
10 to 90% by weight, preferably 20 to 80% by weight of a resin coating component having a primer resin layer and a coating resin layer.
Preferably, the above-mentioned problems are solved by applying the resin component to a resin-coated resin part at a temperature of 50 to 100 ° C. or by immersing the resin part in the peeling-off.

[0005] The resin coating film peeling and removing agent of the resin coating film of the resin-coated part having the primer resin layer and the coating resin layer of the present invention is 1,3-dimethyl-2-imidazolidinone compound A in an amount of 10 to 90% by weight. %, Preferably 20 to 80% by weight and a compound B consisting of a monool, diol or thiol, which is in a liquid state at room temperature having a boiling point of 250 ° C. or less.
It is characterized by containing 90% by weight, preferably 20-80% by weight.

[0006]

As the compound A constituting the stripping / removing agent of the resin coating film of the present invention, 1,3-dimethyl-2-imidazolidinone which is an aprotic solvent is used.

The compound B includes 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 represents C _n H 2 _{n + 1} (n = 1 to 10) or an aromatic group].

[0009]

The compound A mainly diffuses / permeates into the primer resin, swells and swells the primer resin, and peels it off. Therefore, when the concentration of Compound A is less than 10% by weight, the primer resin does not sufficiently swell and expand,
The paint does not peel. On the other hand, when the amount of the compound A is more than 90% by weight, the swelling of the coating resin is insufficient and the coating may not be peeled off. When the resin-coated resin component swells with respect to the above-mentioned coating film peeling remover, and when the mass change rate is less than 20%, the swelling of the coating resin is insufficient and the coating resin cannot be peeled. On the other hand, the above-mentioned compound B having a mono-, diol or derivative thereof is used as the release remover for the resin coating film.
Is contained in an amount of 10 to 90% by weight, preferably 20 to 80% by weight. Compound B mainly diffuses / permeates the coating resin, swells and swells the coating resin, and promotes diffusion / permeation of compound A. Further, since compound B has a hydrophilic and lipophilic group, it also has an effect on the penetration of the coating film peeling remover from the interface of the coating resin / primer resin / resin part.

However, when the compound B having a carbon chain length of 10 or more is used, the boiling point exceeds 250 ° C., the viscosity of the solution increases, the lipophilicity increases, the solubility in water decreases significantly, and the resin is removed and removed. Since the film wettability and diffusion / penetration by the agent and the workability such as the drying step are impaired, n-
Dodecyl alcohol is not suitable for use. On the other hand, 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 stripping / removing agent for resin coatings of the present invention is particularly preferably used for stripping / removing resin coatings from acrylic-, melamine- or urethane-based resin paint-treated resin parts. The peeling removal can be carried out by spraying or applying the peeling remover to the resin paint part as described above, or by immersing the resin paint part in the peel remover.

Next, the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a cross section of a resin-coated part. From the painted surface side,
It comprises a coating resin layer 1, a primer resin layer 2, and a lowermost resin base material 3. Using the resin film peeling remover and the peeling removal method of the present invention, from the resin coated parts,
Fig. 2 (a) shows three types of peeling mechanisms for removing and removing paint.
(b) and (c). FIG. 2A shows that the coating resin layer 1 swells and expands significantly as compared to the primer resin layer 2 mainly due to the action of the compound B, and peels off near the interface 4 between the coating resin layer 1 and the primer resin layer 2. Conversely, in FIG. 2 (b), the primer resin 2 swells and expands significantly compared to the coating resin layer 1 mainly due to the action of the compound A, and the coating resin layer 1 / primer resin layer 2 or the primer resin layer 2 / resin This indicates that the separation occurs near the interface 4 of the substrate 3. Next, in FIG. 2 (c), the coating resin layer 1 and the primer resin layer 2 swell and swell due to the action of both the compounds A and B, but the swelling of the primer layer 2 having a low degree of curing remarkably progresses, and 2 / It is shown that peeling occurs near the interface 4 of the resin substrate 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. In addition, paint peeling is observed. In addition, in the above-mentioned coating peeling, no swelling or swelling of the resin base material 3 is observed. The degree of swelling (ΔWs) is defined as follows. ΔWs (%) = 100 (Ws−Wo) / Wo Wo: Swelling with paint film removing agent, coating resin layer 1 before swelling
Alternatively, the weight of the primer resin layer 2 Ws: after swelling and swelling with the coating film peeling and removing agent (temperature: 50 to 1
Weight of coating resin layer 1 or primer resin layer 2 (50 ° C, treatment time: 15 minutes)

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

[0015]

The present invention will be described below with reference to examples and comparative examples. Preparation example of resin film peeling and removing agent The compounds A (liquid) and B (liquid) were poured into each beaker at room temperature, weighed by an automatic balance to a predetermined weight, and the two liquids were mixed. The mixture was agitated with a sliver to prepare a peeling remover for the resin coating film.

Tables 1 and 2 show the results of the evaluation of the removal of the coating film, and specific preparation examples of the coating film removing agent are shown. In addition, industrially, it is also possible to prepare the resin coating decomposition removal agent by weighing the volume in terms of weight using the density of the compounds A and B.

[0017] In the resin coating film decomposed and removed Evaluation Test Examples proper amount of peel removal agent of the resin film (about 100ml) placed in a round-bottom flask magnetic stirrer stirring element,
The mixture was refluxed until the set temperature (50/150 ° C.) was reached. After keeping the peeling remover at a set temperature, five pieces of about 10 mm wide × about 10 mm long × about 2 mm thick cut out from the resin-coated resin part are put into a flask, and the decomposition remover It was immersed, left for 30 minutes, and observed. Thereafter, the split pieces were taken out of the flask, and the state of decomposition and removal of the resin coating was visually determined.

In the evaluation of removal of paint peeling in Tables 1 and 2,
Specific evaluation test examples are shown. In addition, the kind of resin coating treatment resin used for the evaluation test was two kinds (I, II), and both were:
The chemical compositions of the coating resin and primer resin are different. Table 1,
In Table 2, when a change was observed in the coating resin and the primer resin after the evaluation test, a mark ◎ indicates that the primer resin was decomposed or swelled and peeled, and a mark ○ indicates that the coating resin was decomposed or swelled and peeled. When partial dissolution, decomposition, or swelling and peeling were observed, the number of changes was shown in the list of Δ marks, and in the case of no change, the number of changed pieces was shown in the list (5 test samples each).

Example 1 About 10% of a stripping and removing agent (1,3-dimethyl-2-imidazolidinone / ethanol = 10% by weight / 90% by weight) of a resin coating film
Take 0 ml into a 200 ml eggplant-shaped flask, stir on a water bath with a magnetic stirrer,
(50 ° C., 80 ° C. or 100 ° C.). next,
Cut out 5 pieces (width × length × thickness = 10 × 10 × 2 mm) of each of the resin-coated parts (painted products I and II), immerse them in the resin film peeling / removal agent in the flask, and treat for 30 minutes did. Thereafter, 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 checked. The results obtained are as shown in Table 1. Examples 2 to 5 and Comparative Examples 1 to 14 Table 1 shows the predetermined temperatures using the stripping and removing agents for the resin coatings of Examples 2 to 5 shown in Table 1 and Comparative Examples 1 to 14 shown in Table 2. Except that the temperature (water bath or oil bath heating) was used, the split pieces of the resin-coated part 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 checked. did. The obtained results are as shown in Tables 1 and 2.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

As described above, the resin stripping / decomposing / removing agent of the present invention has a concentration of 10 to 90% by weight of compound A.
And 10 to 90% by weight of Compound B,
At a temperature of 50 to 150 ° C., the delamination-removing agent is sprayed or applied to the resin-coated resin parts, or is immersed / applied to the decomposition-removing agent, or is exposed to the vapor of the removing agent, thereby deteriorating environmental health. Also, the effect that the resin coating film can be efficiently decomposed and removed without causing ozone layer destruction can be obtained successfully. In addition, since the primer surface is also removed at the same time, when kneading or the like is performed using these materials, corrosion of the contact surface of the processing equipment is prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of a resin part subjected to a resin coating treatment.

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

[Explanation of symbols]

 Reference Signs List 1 coating resin layer 2 primer resin layer 3 resin substrate 4 coating film peeling part

Continuation of the front page (56) References JP-A-63-163457 (JP, A) JP-A-49-45945 (JP, A) JP-A-4-293974 (JP, A) JP-A-4-293975 (JP) , A) JP-A-5-93157 (JP, A) JP-B-45-12925 (JP, B1) (58) Fields investigated (Int. Cl. ⁶ , DB name) C09D 9/00-9/04

Claims (3)

(57) [Claims] 1. A monool, diol or thiol, which is in a liquid state at 10 to 90% by weight of 1,3-dimethyl-2-imidazolidinone compound A and a boiling point of 250 ° C. or less at room temperature. A stripping / removing agent for a resin coating of a resin-coated part having a primer resin layer and a coating resin layer, comprising 10 to 90% by weight of Compound B. 2. An acrylic, melamine or urethane resin paint at a temperature of 50 to 150 ° C.
When swelled with a stripping and removing agent for a resin coating consisting of a mixed solution of the described compound A and compound B, the swelling ratio (ΔWs)
% Or more. 3. The method according to claim 1, wherein the resin coating stripping and removing agent is sprayed or applied to the resin-coated part at 50 to 150 ° C.
Alternatively, a method for stripping and removing a resin coating film, comprising immersing a resin-coated component in the stripping and removing agent for the resin coating film.