JP4671118B2 - Repair multilayer coating film and method for producing repair multilayer coating film - Google Patents

Description

  The present invention relates to a repair coating film for repairing coating defects such as blisters produced in a top coating film containing polyrotaxane, and a method for producing the repair coating film.

Conventionally, if a coating defect such as a projecting portion (commonly known as “butsu”) due to adhesion of foreign matter or the like has occurred in a coating film of a top-coated object, the portion is repaired.
As a method for repairing the top coat, there is a method in which a repair site where a coating defect has occurred is sharpened, and the same top coat as that used in the top coat is applied for repair.

However, in this method, the top coating material often scatters around the repair site, and a convex portion is generated in the non-repair site due to adhesion of the paint dust, so that the appearance of the object to be coated is impaired. Therefore, the repaired area is sharpened with paper, and the top coat is applied, then the paint dust is sprayed onto the paint dust, and finally baked, polished with compound-containing wax, and finished with wax. Therefore, it is made inconspicuous that the repair site scratches and paint dust remain in a convex shape so that the appearance is not impaired (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 62-124460

However, in a top coat film having good scratch resistance such as containing polyrotaxane, there is a problem that the repair site cannot be ground with the compound-containing wax, or the scratch cannot be made inconspicuous even after being repaired by grinding.
In addition, there is a problem that scratch resistance cannot be imparted upon repair.

  The present invention has been made in view of such problems of the prior art, and the object of the present invention is to repair marks for coating film defects of a scratch-resistant coating film containing polyrotaxane. Therefore, it is an object of the present invention to provide a repaired laminated coating film and a method for producing the repaired coating film that can realize repairs that are not conspicuous and can realize compatibility with scratch resistance.

  As a result of intensive studies to achieve the above object, the present inventors have found that the above object can be achieved by using a paint containing a predetermined polyrotaxane and a paint not containing this, thereby completing the present invention. It came to do.

That is, the coating film multilayer coating film of the present invention comprises an undercoat film layer and a PR-containing topcoat film layer containing a lipophilic polyrotaxane or a hydrophilic polyrotaxane, and the PR-containing topcoat film layer has a coating film defect. It is a repaired laminated coating film obtained by repairing a film.
The PR-containing topcoat coating layer comprises a grinding part formed by grinding the coating film defect, a PR-free repair coating layer and a PR-containing repair coating layer sequentially laminated on the grinding part,
The PR-free repair coating layer is a coating layer formed from a PR-free repair top coating that does not contain a lipophilic polyrotaxane or a hydrophilic polyrotaxane,
The PR-containing repair coating layer is a coating layer formed from a PR-containing repair top coating containing a lipophilic polyrotaxane or a hydrophilic polyrotaxane.

  Moreover, the suitable form of the repair lamination coating film of this invention is the lipophilic polyrotaxane or hydrophilic polyrotaxane contained in the said PR containing top coat film layer, and the lipophilic polyrotaxane or hydrophilic property contained in the said PR containing repair coating film layer. The polyrotaxane is the same species.

Furthermore, another preferred embodiment of the repair laminated coating film of the present invention is formed by adding a base coat film layer between the undercoat film layer and the PR-containing top coat film layer, and the ground portion is coated with the base coat film. Reaching the membrane layer,
In this deep grinding part, a repair base coat film layer having substantially the same components as the base coat film layer, a PR-free repair paint film layer, and a PR-containing repair paint film layer are sequentially laminated. It is characterized by.

On the other hand, the method for producing a repaired laminated coating film of the present invention is a method for producing a repaired laminated coating film as described above.
The coating film defect is ground to form a grinding part, and then the PR-free repair top coating and the PR-containing repair top coating are sequentially applied to the grinding part.

Moreover, the other preparation method of the repair lamination coating film of this invention is a method of producing the above repair lamination coating film.
The coating film defect is ground to form the deep grinding site, and then the repair base coat coating layer is formed on the deep grinding site, the PR-free repair top coating and the PR It is characterized by being formed by sequentially applying a top coating for repairing.

  According to the present invention, since a paint containing a predetermined polyrotaxane and a paint containing no polyrotaxane are used in combination, the repair marks are conspicuous with respect to coating film defects of a scratch-resistant coating containing polyrotaxane. In addition, it is possible to provide a repair laminated coating film capable of realizing a repair capable of achieving compatibility with the scratch resistance and a method for producing the same.

Hereinafter, the repair laminated coating film of the present invention and the method for producing the repair laminated coating film will be described in detail. In the present specification, “%” represents mass percentage unless otherwise specified.
As described above, the repair laminate film of the present invention is a repair of a laminate film comprising an undercoat film layer and a PR-containing topcoat film layer containing a lipophilic polyrotaxane or a hydrophilic polyrotaxane. It is formed by repairing coating film defects such as bumps existing in the coating layer.
The PR-containing topcoat coating layer includes a ground portion formed by grinding a coating-film defect, and a PR-free repair coating layer and a PR-containing repair coating layer sequentially laminated on the ground portion.
The PR-free repair coating layer is formed from a PR-free repair coating that does not contain a lipophilic polyrotaxane or hydrophilic polyrotaxane, while the PR-containing repair coating layer is a lipophilic polyrotaxane or hydrophilic. It is formed from a PR-containing repair topcoat containing polyrotaxane.

As described above, the repair laminate film of the present invention has at least an undercoat film layer and a PR-containing topcoat film layer. You may have a film layer.
The PR-containing topcoat layer may be any coating layer containing a lipophilic or hydrophilic polyrotaxane. In the present invention, the PR-containing topcoat layer is formed from an enamel paint in addition to the so-called clear coat layer. The enamel coating layer to be applied can be handled in the same manner as the top coating layer.

In the repaired laminate coating layer of the present invention, the PR-free repair coating layer and the PR-containing repair coating layer are present at the grinding site formed by grinding coating film defects such as blisters with sandpaper or the like. Laminated sequentially.
In this case, the PR-free repair coating layer is formed from a top coating that does not contain an oleophilic or hydrophilic polyrotaxane (PR-free repair top coating). You can use paint.

  Specifically, as a curable paint, a melamine curable acrylic paint, a melamine curable polyester paint, a two-component acrylic urethane paint and a two-component polyester urethane paint, and as an ever-drying paint, an acrylic paint, a melamine paint, Examples thereof include urethane paints and polyester paints.

On the other hand, the PR-containing repair coating layer needs to be formed from a top coat (PR-containing repair top coat) containing a lipophilic or hydrophilic polyrotaxane.
Although these lipophilic or hydrophilic polyrotaxanes will be described later, the lipophilic polyrotaxane is soluble in an organic solvent and functions as a curable or room temperature drying solvent-based coating material. It is soluble in water-based solvents and functions as a curable or room temperature drying-type water-based paint material.

  The PR-containing top coating for repair is a top coating containing a lipophilic or hydrophilic polyrotaxane, and the curable type is a melamine curable acrylic paint, a melamine curable polyester paint, or a two-component acrylic urethane paint. Examples of the two-component polyester urethane paint and the normally dry type include acrylic paints, melamine paints, urethane paints, and polyester paints.

  As described above, in the repair laminate film of the present invention, it is sufficient that both the PR-containing topcoat film layer and the PR-containing repair topcoat film layer contain a lipophilic or hydrophilic polyrotaxane. The polyrotaxane contained in the PR-containing topcoat layer may be hydrophilic and the polyrotaxane contained in the PR-containing repair coating layer may be oleophilic, and also included in the PR-containing topcoat layer The polyrotaxane used may be for a normally dry paint, and the polyrotaxane contained in the PR-containing repair coating layer may be used for a curable paint.

However, considering the compatibility of both polyrotaxanes, the same species, for example, lipophilic for lipophilic, hydrophilic for hydrophilic, curable for curable, and normally dry In contrast, it is preferable to select so as to be a normal dry type, and it is more preferable that the chemical structures of the polyrotaxanes are the same, and the component compositions of the PR-containing top coating and the PR-containing repair top coating are exactly the same. Most preferably.
From the viewpoint of shortening the repair time, it is desirable that at least the polyrotaxane contained in the PR-containing repair coating is for a water-based or organic solvent-based curable coating.

As described above, the repair laminated coating film of the present invention may have an intermediate coating film layer or a base coating film layer. For example, the base coating film layer includes a base coating film layer and a PR-containing top coating film. It is added between the membrane layers.
In such a laminated coating film, a coating film defect may be caused by foreign matter adhering to the base coat film layer. In this case, it is necessary to allow the ground portion to reach the base coat film layer. In the present invention, a repair base coat film layer, a PR-free repair paint film layer, and the PR-containing repair paint film layer having substantially the same components as the base coat film layer are sequentially laminated on the deep ground portion. The repair is carried out.

Examples of the base coat paint used for forming such a base coat coating film layer include conventionally known ones. Examples of the curable paint include melamine curable acrylic paint, melamine curable polyester paint, two-component acrylic urethane paint, and Examples of the two-component polyester urethane paint and the normally dry paint include acrylic paint, melamine paint, urethane paint, and polyester paint.
In addition, the base coat film layer may contain a color pigment or a glitter material, and further, the enamel paint or the top coat paint may contain a color pigment or a glitter material.
The base coat paint for repair used for forming the base coat film layer for repair may be a conventionally known base coat paint, but the component composition or form of the base coat paint for forming the base coat film layer is the same. It is preferable to use it.

Next, a method for producing the repaired laminated coating film of the present invention will be specifically described with reference to the drawings.
FIG. 1 is a cross-sectional explanatory view showing step by step in a method for producing a repaired laminated coating film of the present invention. In FIG. 1A, a laminated coating film 100 to be repaired is formed by laminating an undercoat coating layer 10, an intermediate coating layer 20, a base coating layer 30 and a PR-containing top coating layer 40 in this order. The PR-containing topcoat film layer 40 that is configured and contains a lipophilic or hydrophilic polyrotaxane and has good scratch resistance has a coating film defect 50.

  In the present invention, first, the coating film defect 50 is ground with sandpaper or the like to form a ground portion 52. This grinding can also be performed by polishing with a wax containing a compound.

Next, a PR-free repair topcoat, which is a repair paint that does not contain the polyrotaxane, is applied to the ground portion 52 to form a PR-free repair coating layer 60 (see FIG. 1B). ).
In addition, it is possible to apply the top coating for PR-free repairing in a plurality of times. In this case, the dilution rate of the coating is gradually increased from the viewpoint of familiarity with the surrounding unrepaired parts (matching the appearance). It is preferable to make it high.

Next, a thinner (not shown) is applied in the vicinity of the boundary between the PR-free repair coating layer 60 and the PR-containing topcoat coating layer 40 (see FIG. 1C).
As this thinner, for example, a solvent for PR-containing top coating can be used, and by applying this thinner, it is possible to improve the compatibility with surrounding unrepaired parts.

Next, the PR-containing repair coating layer 70 containing the polyrotaxane is applied on the PR-free repair coating layer 60 to form the PR-containing repair coating layer 70. The coating material is preferably applied in a small area so that the coating material does not protrude from the PR-free repair coating layer 60.
After applying such a repair paint, it is heated (for example, at 80 ° C. for 30 minutes) or at room temperature according to the type of the repair paint, that is, a curing type or a normal dry type, and the PR-containing repair coating layer 70 is applied. (See FIG. 1D)

  Thereafter, the PR-containing topcoat film layer 40 is polished to remove the surplus portion of the PR-containing repair coating film layer 70, thereby completing the production of the repaired coating film 100R that repairs the coating film defect 50 of the multilayer coating film 100. (Refer to FIG. 1E.)

FIG. 2 is a cross-sectional explanatory view showing step by step each step in another example of the method for producing a repaired laminated coating film of the present invention. In addition, the same code | symbol is attached | subjected to the member and element demonstrated above, and the description is abbreviate | omitted.
In FIG. 2 (A), the laminated coating film 110 to be repaired has a coating film defect 50 in the PR-containing top coating film layer 40. In this example, the coating film defect 50 is formed on the base coating film layer 30. This is due to the adhered foreign matter 50 '.

Similarly to the above, the coating film defect 50 is first ground with sandpaper or the like. In this example, the grinding is performed until the base coating film layer 30 is ground in order to remove the foreign matter 50 ′ existing on the base coating film layer 30. In so doing, a deep grinding site 54 is formed.
Next, a repair base coat paint layer 80 of the same type as the base coat paint used for forming the base coat paint film layer 30 is applied to the deep ground portion 54 to form a repair base coat paint film layer 80. The same treatment is performed to form a PR-free repair coating layer 60 (see FIG. 2B).

  Thereafter, a thinner coating is performed in the same manner as described above (see FIG. 2C), and a PR-containing repair coating layer 70 is further laminated (see FIG. 2D). The layer 40 is polished, the excess of the PR-containing repair coating layer 70 is removed, and the preparation of the repair laminate coating 110R that repairs the coating film defect 50 of the laminate coating 110 is completed (FIG. 2E) reference.).

  In the method for producing a repaired multi-layer coating film of the present invention, as described with reference to FIGS. Since there is no repair coating layer 70 for repair, the vicinity of this boundary can be polished, and repair can be performed with a good appearance.

Hereinafter, the lipophilic polyrotaxane or the hydrophilic polyrotaxane used in the repair laminate coating film and the repair laminate coating method of the present invention will be described in detail.
First, a polyrotaxane is a compound having a cyclic molecule, a linear molecule that includes the cyclic molecule in a skewered manner, and a blocking group that is disposed at both ends of the linear molecule and prevents the elimination of the cyclic molecule. It is.
The repair laminated coating film of the present invention is a blend of a lipophilic polyrotaxane or a hydrophilic polyrotaxane that functions as a coating material among the polyrotaxanes described above.

First, the lipophilic polyrotaxane will be described.
This lipophilic polyrotaxane is one in which at least one of a linear molecule and a cyclic molecule in the above polyrotaxane has hydrophobicity, and functions as a curable or room temperature drying type solvent-based coating material.

Specifically, such a lipophilic polyrotaxane is, in principle, (i) a combination of a hydrophobic linear molecule and a hydrophilic cyclic molecule or a hydrophobic cyclic molecule, or (b) a hydrophilic It is sufficient that the polyrotaxane exhibits lipophilicity as a whole, although it relates to a combination of a functional linear molecule and a hydrophobic cyclic molecule.
In order to impart hydrophobicity to the cyclic molecule, (1) all or part of the hydroxyl group of the cyclic molecule having a hydroxyl group may be modified with a hydrophobic modifying group, and (2) the linear molecule is hydrophobic. In order to impart the property, a specific linear molecule may be selected. In addition, (3) the whole polyrotaxane can be hydrophobized also by controlling the amount by which the linear molecule includes the cyclic molecule.

In the present invention, the lipophilic polyrotaxane may be crosslinked as long as it is soluble in an organic solvent, and the lipophilic crosslinked polyrotaxane may be used instead of the non-crosslinked lipophilic polyrotaxane or this. It can be used as a mixture.
Examples of such a lipophilic crosslinked polyrotaxane include a lipophilic polyrotaxane crosslinked with a polymer having a relatively low molecular weight, typically a polymer having a molecular weight of about several thousand.

  On the other hand, the hydrophilic polyrotaxane is one in which at least one of a linear molecule and a cyclic molecule in the polyrotaxane has hydrophilicity, and functions as a curable or room temperature drying type water-based coating material.

Specifically, among the polyrotaxanes, such a hydrophilic polyrotaxane is, in principle, (c) a combination of a hydrophilic linear molecule and a hydrophilic cyclic molecule or a hydrophobic cyclic molecule, or (d) a hydrophobic However, it is sufficient that the polyrotaxane exhibits hydrophilicity as a whole.
In order to impart hydrophilicity to the cyclic molecule, (4) all or part of the hydroxyl group of the cyclic molecule having a hydroxyl group may be modified with a hydrophobic modifying group.

In the present invention, the hydrophilic polyrotaxane may be crosslinked as long as it is soluble in an aqueous solvent, and the hydrophilic crosslinked polyrotaxane may be used instead of the non-crosslinked lipophilic polyrotaxane or It can be used as a mixture.
Examples of such a hydrophilic cross-linked polyrotaxane include a hydrophilic polyrotaxane crosslinked with a relatively low molecular weight polymer, typically a polymer having a molecular weight of about several thousand.

The above-described lipophilic polyrotaxane is soluble in an organic solvent, and the hydrophilic polyrotaxane is soluble in an aqueous solvent. Therefore, the above-described lipophilicity and hydrophilicity are imparted to a reaction field of an organic solvent or an aqueous solvent, typically a cross-linking, with respect to a polyrotaxane that has been hardly soluble or insoluble in an organic solvent or an aqueous solvent. It provides a place.
That is, the above-described lipophilic polyrotaxane and hydrophilic polyrotaxane can be said to have improved reactivity in which crosslinking with other polymers and modification with a modifying group can be easily performed in the presence of an organic solvent or an aqueous solvent.

FIG. 3 is a schematic diagram conceptually showing the basic structure of polyrotaxane.
In the figure, this polyrotaxane 5 has a linear molecule 6, a plurality of cyclic molecules 7, and blocking groups 8 arranged at both ends of the linear molecule 6, and the linear molecule 6 is cyclic. The cyclic molecule 7 is included through the opening of the molecule 7.
The polyrotaxane having such a structure is excellent in stretchability and viscoelasticity, and is free from cracks and scratches because the cyclic molecules 7 move freely along the straight-chain molecules 6 when an external force is applied (pulley effect). It has the outstanding characteristic that it is hard to produce.

In the present invention, (A) one or both of the cyclic molecule 7 and the linear molecule 6 are hydrophobic and exhibit lipophilicity as a whole. Typically, the cyclic molecule 7 has a hydroxyl group. In addition, a polyrotaxane in which all or part of the hydroxyl groups of these cyclic molecules are modified with a hydrophobic modifying group, a polyrotaxane having a hydrophobic linear molecule,
Or (B) a hydrophilic polyrotaxane in which one or both of the cyclic molecule 7 and the linear molecule 6 have hydrophilicity and show hydrophilicity as a whole, typically, the cyclic molecule 7 has a hydroxyl group, and these cyclic molecules A polyrotaxane in which all or part of the hydroxyl groups of the molecule is modified with a hydrophilic modifying group is blended.

  In addition, when a coating coating for PR containing a repair containing a lipophilic polyrotaxane (or hydrophilic polyrotaxane) is applied to the repair site during coating film repair, the coating resin, which is a coating film forming component of the coating film having the repair site, is used. It is presumed that oily polyrotaxane (or hydrophilic polyrotaxane) coexists and both crosslink or pseudo-crosslink, and both cross-linked products and pseudo-crosslinked products are formed at the repair site, so that repair can be performed without reducing the scratch resistance. It seems to be done.

FIG. 4 is a partial conceptual diagram conceptually showing a cross-linked structure between a lipophilic polyrotaxane (or hydrophilic polyrotaxane) and a coating resin.
In the figure, a crosslinked polyrotaxane 1 produced by crosslinking both has paint resins 3, 3 ′ and the lipophilic polyrotaxane (or hydrophilic polyrotaxane) 5. The crosslinked polyrotaxane 1 is bonded to the coating resin 3 and the coating resin 3 ′ through the cyclic molecules 7 through the crosslinking points 9.

When a deformation stress in the direction of arrow XX ′ in FIG. 4A is applied to the crosslinked polyrotaxane 1 having such a structure, the crosslinked polyrotaxane 1 is deformed as shown in FIG. 4B. The stress can be absorbed.
That is, as shown in FIG. 4B, since the cyclic molecule 7 can move along the linear molecule 6 by the pulley effect, the crosslinked polyrotaxane 1 can absorb the stress therein.
Therefore, the repaired site in which such a crosslinked polyrotaxane is formed has the property that it is excellent in stretchability and viscoelasticity, and is less prone to cracks and scratches.

On the other hand, even when the lipophilic polyrotaxane (or hydrophilic polyrotaxane) and the coating resin are not crosslinked, they approach each other and cause pseudo-crosslinking due to van der Waals force, etc. It is thought that it behaves as
Even in such a case, at least the lipophilic polyrotaxane (or hydrophilic polyrotaxane) exerts the pulley effect described above, so that the repaired part repaired with the above-mentioned PR-containing repair topcoat has the same elasticity and viscoelasticity as above. It is excellent and has the property that cracks and scratches are unlikely to occur.

Hereinafter, the lipophilic polyrotaxane will be specifically described.
In the lipophilic polyrotaxane, the hydrophobic modifying group has a hydrophobic group or a hydrophobic group and a hydrophilic group, and may be hydrophobic as a whole.
Examples of the hydrophobic group include an alkyl group, a benzyl group (benzene ring) and a benzene derivative-containing group, an acyl group, a silyl group, a trityl group, a nitrate ester group, and a tosyl group.
Examples of the hydrophilic group include a carboxyl group, a sulfonic acid group, a sulfate ester group, a phosphate ester group, an amino group (primary to tertiary), a quaternary ammonium base, and a hydroxyalkyl group.

The cyclic molecule in the lipophilic polyrotaxane is not particularly limited as long as it is included in a linear molecule and exhibits a pulley effect, and various cyclic substances can be mentioned. Many cyclic molecules have a hydroxyl group.
In addition, it is sufficient that the cyclic molecule is substantially cyclic, and it is not necessarily required to be completely closed like “C” shape.

Further, as the cyclic molecule, those having a reactive group are preferable, and this facilitates the binding with the above-described hydrophobic modifying group or the like.
Such a reactive group is a residue derived from a compound bonded to a hydroxyl group of a cyclic molecule, and examples thereof include a hydroxyl group, a carboxyl group, an amino group, an epoxy group, an isocyanate group, a thiol group, and an aldehyde group. However, it is not limited to these. In addition, as a reactive group, when forming the blocking group mentioned later (blocking reaction), the group which does not react with this blocking group is preferable.

The degree of modification of the cyclic molecule with the hydrophobic modifying group in the hydrophobic polyrotaxane used in the present invention is 0.02 or more when the maximum number of hydroxyl groups that the cyclic molecule can be modified is 1. Preferably, it is 0.04 or more, more preferably 0.06 or more.
If the modification degree is less than 0.02, the solubility in an organic solvent may not be sufficient, and insoluble matter may be generated.

  The maximum number of hydroxyl groups that can be modified in the cyclic molecule means the total number of hydroxyl groups that the cyclic molecule had before modification. The degree of modification is, in other words, the ratio of the number of modified hydroxyl groups to the total number of hydroxyl groups.

  Furthermore, when the polyrotaxane has a plurality of cyclic molecules, it is not necessary that all or a part of the hydroxyl groups of each cyclic molecule is modified with a hydrophobic modifying group. In other words, as long as the entire polyrotaxane exhibits hydrophobicity, there may be no problem even if a cyclic molecule having a hydroxyl group that is not modified by the hydrophobic modifying group is partially present.

As a method for introducing the hydrophobic modifying group, the following method can be employed.
As an example, cyclodextrin is used as a cyclic molecule of polyrotaxane, the hydroxyl group of the cyclodextrin is hydroxypropylated using propylene oxide, ε-caprolactone is added, and tin 2-ethylhexanoate is added. The modification rate can be arbitrarily controlled by changing the amount of ε-caprolactone added at this time.

In the lipophilic polyrotaxane, the number (inclusion amount) of the cyclic molecule included in the linear molecule is 0 when the maximum inclusion amount that the linear molecule can include the cyclic molecule is 1. 06-0.61 are preferable, and 0.11-0.22 are still more preferable. If the inclusion amount is 0.06 to 0.17, lipophilicity can be imparted to the target polyrotaxane separately from the modification of the cyclic molecule and the selection of the linear molecule described later.
If this ratio is less than 0.06, the pulley effect may be insufficient and the elongation of the repaired part may be reduced. If it exceeds 0.61, the cyclic molecules will be arranged too densely, the mobility of the cyclic molecules will decrease, the elongation rate of the coating film formed at the repair site will be insufficient, and the scratch resistance will tend to deteriorate. is there.

Further, the amount of inclusion of the cyclic molecule can be controlled as follows.
As an example, BOP reagent (benzotriazol-1-yl-oxy-tris (dimethylamino) phosphonium hexafluorophosphate), HOBt, adamantamine, and diisopropylethylamine are added to DMF (dimethylformamide) in this order. Make a solution. On the other hand, a solution is obtained in which a clathrate complex in which a cyclic molecule is skewered into a linear molecule is dispersed in a DMF / DMSO (dimethyl sulfoxide) mixed solvent. By mixing these two and changing the mixing ratio of DMF / DMSO at this time, the inclusion amount of the cyclic molecule can be arbitrarily controlled. In addition, the higher the DMF / DMSO ratio, the greater the amount of inclusion of the cyclic molecule.

  Specific examples of the cyclic molecule include various cyclodextrins such as α-cyclodextrin (glucose number: 6), β-cyclodextrin (glucose number: 7), and γ-cyclodextrin (glucose number: 8). ), Dimethylcyclodextrin, glucosylcyclodextrin and derivatives or modified products thereof, and crown ethers, benzocrowns, dibenzocrowns, dicyclohexanocrowns and derivatives or modified products thereof.

The above-mentioned cyclic molecules such as cyclodextrin can be used alone or in combination of two or more.
Of the various cyclic molecules described above, α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin are particularly preferable, and in particular, α-cyclodextrin is used from the viewpoint of inclusion. Is preferred.

On the other hand, the linear molecule may be substantially linear, and may have a branched chain as long as the cyclic molecule that is a rotor can be included so that it can rotate and exert a pulley effect. .
Further, although it is affected by the size of the cyclic molecule, its length is not particularly limited as long as the cyclic molecule can exert a pulley effect.

In addition, as a linear molecule, what has a reactive group in the both ends is preferable, and it becomes possible to react this with the said blocking group easily by this.
Such a reactive group can be appropriately changed according to the type of blocking group employed, and examples thereof include a hydroxyl group, an amino group, a carboxyl group, and a thiol group.

Such a linear molecule is not particularly limited, and is a polyester such as polyalkylenes or polycaprolactone, a polyether such as polypropylene glycol or polyethylene glycol, polyisoprene, polybutadiene, polytetrahydrofuran, polydimethyl. Mention may be made of siloxane, polyethylene, polypropylene, polyamides, polyacryls and linear molecules having a benzene ring.
Among these linear molecules, polyethylene glycol and polycaprolactone are particularly preferable, and polyethylene glycol is preferably used from the viewpoint of solubility in water or solvent solvents.
If polycaprolactone is selected as the linear molecule, lipophilicity can be imparted to the polyrotaxane separately from the modification of the cyclic molecule and the control of the maximum inclusion amount.

In addition, the molecular weight of the linear molecule is preferably 1,000 to 100,000, and more preferably 10,000 to 50,000.
If the molecular weight of the linear molecule is less than 1,000, the pulley effect due to the cyclic molecule cannot be sufficiently obtained, and the scratch resistance may be deteriorated. When the molecular weight exceeds 100,000, the compatibility with the transparent resin is lowered, and the transparency may be lowered.
In addition, when polycaprolactone is selected as the linear molecule, if the molecular weight is 5,000 to 100,000, lipophilicity can be imparted to the polyrotaxane well.

On the other hand, the blocking group may be any group as long as it is arranged at both ends of the linear molecule as described above and can keep the cyclic molecule pierced by the linear molecule. It can be a group.
Examples of such a group include a group having “bulkiness” or a group having “ionicity”. Here, the “group” means various groups including a molecular group and a polymer group.

Examples of the group having “bulkyness” include a spherical shape and a side wall-shaped group.
In addition, the ionicity of the group having “ionicity” and the ionicity of the cyclic molecule interact with each other, for example, repelling each other, so that the cyclic molecule is skewed into a linear molecule. Can be held.

  Specific examples of such blocking groups include dinitrophenyl groups such as 2,4-dinitrophenyl group and 3,5-dinitrophenyl group, cyclodextrins, adamantane groups, trityl groups, fluoresceins and pyrenes. And derivatives or modified products thereof.

Here, an example of the manufacturing method of the lipophilic polyrotaxane used for this invention is demonstrated.
As mentioned above, the lipophilic polyrotaxane is
(1) mixing a cyclic molecule and a linear molecule, penetrating the opening of the cyclic molecule in a skewered manner with the linear molecule, and including the cyclic molecule in the linear molecule;
(2) a step of preparing both the ends of the obtained pseudopolyrotaxane (both ends of the linear molecule) with a blocking group so that the cyclic molecule is not detached from the skewered state;
(3) a step of modifying the hydroxyl group of the cyclic molecule of the obtained polyrotaxane with a hydrophobic modifying group,
Is obtained by processing.

  In the step (1), a lipophilic polyrotaxane can also be obtained by using a hydroxyl group of the cyclic molecule that has been modified with a hydrophobic modifying group in advance. In that case, the step (3) is performed. Can be omitted.

By this production method, as described above, a lipophilic polyrotaxane excellent in solubility in an organic solvent can be obtained.
The organic solvent is not particularly limited, but alcohols such as isopropyl alcohol and butyl alcohol, esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, diethyl ether and dioxane. And ethers such as toluene and hydrocarbon solvents such as toluene and xylene. The lipophilic polyrotaxane exhibits good solubility even in a solvent in which two or more of these are mixed.

  In addition, as described above, the lipophilic polyrotaxane blended in the PR-containing repair topcoat crosslinks or pseudo-crosslinks with the coating film forming component of the coating film to be repaired, particularly the paint resin. Alternatively, the pseudo-crosslinked polyrotaxane is a composite of the coating resin and the polyrotaxane without impairing the physical properties of the lipophilic polyrotaxane and the coating resin to be crosslinked.

Usually, the crosslinked polyrotaxane is obtained by (a) mixing a lipophilic polyrotaxane with other coating film forming component, (b) physically and / or chemically crosslinking at least a part of the coating film forming component, and (c) It is formed by bonding at least a part of the coating film-forming component and a lipophilic polyrotaxane via a cyclic molecule (curing reaction).
Moreover, these processes can be performed more smoothly by using a curing agent.

In the steps (b) and (c), it is preferable to perform chemical crosslinking. For example, the hydroxyl group of the lipophilic polyrotaxane as described above and the melamine resin, which is an example of the coating film forming component, form a urethane bond. By repeating the formation, a crosslinked polyrotaxane is obtained.
The mixing step (a) depends on the coating film forming component to be used, but can be carried out without a solvent or in a solvent. Further, the solvent can be removed by heat treatment or the like when forming the coating film.

In the present invention, the PR-containing repair top coating is applied to the repair site and heated as necessary, thereby crosslinking or imitating the coating film forming component of the coating film to be repaired with the lipophilic polyrotaxane. Cross-linked polyrotaxanes can be generated.
At this time, a curing agent may be used, and the curing agent may be preliminarily blended with the PR-containing repair top coating, but it is made into a so-called two-component type that is used by mixing at the time of application. Is more convenient to handle.

Specific examples of the curing agent include melamine resin, polyisocyanate compound, blocked isocyanate compound, cyanuric chloride, trimesoyl chloride, terephthaloyl chloride, epichlorohydrin, dibromobenzene, glutaraldehyde, phenylene diisocyanate, diisocyanate trilein. , Divinylsulfone, 1,1′-carbonyldiimidazole or alkoxysilanes. In the present invention, these can be used alone or in combination of two or more.
Moreover, the said hardening | curing agent can use the molecular weight below 2000, Preferably it is less than 1000, More preferably, it is less than 600, More preferably, it is less than 400.

Next, the hydrophilic polyrotaxane will be specifically described. In addition, about the matter which is not described, it is the same as the case of the above-mentioned lipophilic polyrotaxane.
In this hydrophilic polyrotaxane, the modifying group has a hydrophilic group or a hydrophilic group and a hydrophobic group, and may be hydrophilic as a whole. Such hydrophilic groups and hydrophobic groups are as described above.

The cyclic molecule is also as described above. Further, as the cyclic molecule, those having a reactive group are preferable, and this facilitates bonding with a hydrophilic modifying group or the like.
Examples of such a reactive group include, but are not limited to, a hydroxyl group, a carboxyl group, an amino group, an epoxy group, an isocyanate group, a thiol group, and an aldehyde group. In addition, as a reactive group, when forming the blocking group mentioned later (blocking reaction), the group which does not react with this blocking group is preferable.

In addition, the degree of modification of the cyclic molecule with the hydrophilic modifying group in the hydrophilic polyrotaxane is preferably 0.1 or more when the maximum number of hydroxyl groups that the cyclic molecule can be modified is 1, More preferably, it is more preferably 0.5 or more.
If the degree of modification is less than 0.1, the solubility in water or an aqueous solvent may not be sufficient, and insoluble bumps may be generated.

  Furthermore, when the polyrotaxane has a large number of cyclic molecules, it is not necessary that all or part of the hydroxyl groups of each cyclic molecule is modified with a hydrophilic group. In other words, as long as the entire polyrotaxane exhibits hydrophilicity, there may be no problem even if a cyclic molecule having a hydroxyl group that is not modified with a hydrophilic group is partially present.

Here, at least one hydrophilic group may be used, but it is desirable to have one hydrophilic group for one cyclic molecule, for example, one cyclodextrin ring.
Further, by introducing a hydrophilic group having a functional group, it becomes possible to improve the reactivity with other polymers.

  In addition, as a method for introducing a hydrophilic modification group into a cyclic molecule of polyrotaxane, for example, when cyclodextrin is used as the cyclic molecule, the hydroxy group of the cyclodextrin may be hydroxypropylated using propylene oxide. In this case, the degree of modification with the hydroxyalkyl group can be controlled by changing the amount of propylene oxide added.

In the hydrophilic polyrotaxane, the number (inclusion amount) of the cyclic molecules included in the linear molecule is 0 when the maximum inclusion amount that the linear molecule can include the cyclic molecule is 1. 06-0.61 are preferable, 0.11-0.48 are more preferable, and 0.24-0.41 are still more preferable.
If the inclusion amount is less than 0.06, the pulley effect may be insufficient, and the elongation of the coating film forming the repair site may be reduced. If it exceeds 0.61, the cyclic molecules are arranged too densely. This is because the mobility of the cyclic molecules is lowered, and similarly, the elongation rate of the coating film is insufficient and the scratch resistance tends to deteriorate.

  Such a linear molecule is not particularly limited, but polyethylene glycol is preferably used from the viewpoint of solubility in water or an aqueous solvent.

Further, the molecular weight of the linear molecule is preferably 1,000 to 40,000, preferably 10,000 to 40,000, and more preferably 20,000 to 35,000. preferable.
When the molecular weight of the linear molecule is less than 1,000, the pulley effect due to the cyclic molecule cannot be sufficiently obtained, the elongation rate of the coating film forming the repair site is lowered, and the scratch resistance is deteriorated, while the molecular weight is 40 If it exceeds 1,000, the solubility in the paint is lowered, and the appearance such as smoothness as a clear coating film tends to deteriorate due to the formation of a film on the surface.

Next, an example of a method for producing the hydrophilic polyrotaxane will be described.
As mentioned above, the hydrophilic polyrotaxane is
(1) mixing a cyclic molecule and a linear molecule, penetrating the opening of the cyclic molecule in a skewered manner with the linear molecule, and including the cyclic molecule in the linear molecule;
(2) a step of adjusting both ends of the obtained pseudopolyrotaxane (both ends of the linear molecule) with a blocking group so that the cyclic molecule is not detached from the skewered state;
(3) a step of modifying the hydroxyl group of the obtained polyrotaxane cyclic molecule with a hydrophilic modifying group,
Is obtained by processing.

  In the step (1), a hydrophilic polyrotaxane can also be obtained by using a hydroxyl group of the cyclic molecule that has been modified with a hydrophilic modifying group in advance. In that case, the step (3) is performed. Can be omitted.

In the present invention, the aqueous solvent means a solvent that interacts with water and has a strong affinity with water. Specifically, for example, isopropyl alcohol, butyl alcohol, ethylene glycol Alcohols such as cellosolve acetate, butyl cellosolve acetate, ether esters such as diethylene glycol monoethyl ether, glycol ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, etc. The hydrophilic polyrotaxane used in the present invention exhibits good solubility even in a solvent in which two or more of these are mixed.
Among these, alcohols are more preferable, and glycol ethers are more preferable. Even if an organic solvent such as toluene is slightly contained, it may be an aqueous solvent as long as it has a strong affinity with water as a whole.

  In addition, the hydrophilic polyrotaxane blended in the PR-containing repair topcoat crosslinks or pseudo-crosslinks with the coating film forming component of the coating film to be repaired, particularly the paint resin, in the same manner as the above lipophilic polyrotaxane. The hydrophilic modifying group and other functional groups of the hydrophilic polyrotaxane react with the coating film forming component to form a coating film having excellent scratch resistance and chipping resistance. In addition, cracks and the like hardly occur, and the weather resistance, stain resistance, adhesion, and the like are excellent.

  Similarly to the case of the lipophilic polyrotaxane, the crosslinked or pseudo-crosslinked polyrotaxane by the hydrophilic polyrotaxane can be used for the coating film-forming component and the polyrotaxane without impairing the physical properties of the coating film-forming component to be crosslinked by the hydrophilic polyrotaxane. Can be said to be a complex. Therefore, as described below, by forming a crosslinked polyrotaxane in the repair coating film, a coating film having the physical properties of the coating film forming component and the physical properties of the hydrophilic polyrotaxane itself can be obtained, and the polymer type and the like can be selected. By doing, it can be set as the repair coating film which has desired mechanical strength.

Here, the crosslinking of the hydrophilic polyrotaxane will be described.
This crosslinked polyrotaxane is usually
(A) mixing a hydrophilic polyrotaxane with other film-forming components,
(B) at least a part of the coating film-forming component is physically and / or chemically crosslinked;
(C) It can be formed by bonding (curing reaction) at least a part of the coating film-forming component and a hydrophilic polyrotaxane via a cyclic molecule.

  In addition, since hydrophilic polyrotaxane is soluble in water or an aqueous solvent, the steps (a) to (c) can be smoothly performed in water, an aqueous solvent, and a mixed solvent thereof. Moreover, these processes can be performed more smoothly by using a curing agent.

  In the steps (b) and (c), it is preferable to perform chemical crosslinking. For example, this is a urethane bond between the hydroxyl group of the cyclic molecule of the hydrophilic polyrotaxane as described above and a melamine resin which is an example of a paint forming component. Is repeatedly formed to obtain a crosslinked polyrotaxane. Moreover, you may implement the (b) process and the (c) process substantially simultaneously.

  The mixing step (a) depends on the coating film forming component to be used, but can be performed in a solvent such as water or an aqueous solvent or without these solvents. Further, the solvent can be removed by heat treatment or the like when forming the coating film.

  It should be noted that the hydrophilic polyrotaxane can be crosslinked or pseudo-crosslinked by application to the repair site of the PR-containing repair top coating, and the use and selection of the heating and curing agent are the same as in the case of the lipophilic polyrotaxane. is there.

  Although the coating film used as the repair object of this invention is not specifically limited, The coating film containing the resin component (paint resin) which can be bridge | crosslinked or pseudo-crosslinked with the lipophilic polyrotaxane or hydrophilic polyrotaxane demonstrated above. The present invention is particularly suitable for repairing automobile paint coatings.

The resin component is not particularly limited, but the main chain or side chain is a hydroxyl group, amino group, carboxyl group, epoxy group, vinyl group, thiol group or photocrosslinking group, and any combination thereof. Those having a group are preferred.
Examples of the photocrosslinking group include cinnamic acid, coumarin, chalcone, anthracene, styrylpyridine, styrylpyridinium salt, and styrylquinoline salt.

Moreover, although the coating film in which 2 or more types of these resin components are mixed and used may be sufficient, it is desirable in this case that at least 1 type of resin component has couple | bonded with the polyrotaxane through the cyclic molecule.
Further, the resin component may be a homopolymer or a copolymer. In the case of a copolymer, it may be composed of two or more monomers, and may be a block copolymer, an alternating copolymer, a random copolymer or a graft copolymer.

Specific examples include polyvinyl alcohol, polyvinyl pyrrolidone, poly (meth) acrylic acid, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and other cellulose resins, polyacrylamide, polyethylene oxide, polyethylene glycol, polypropylene glycol, polyvinyl acetal resins, Polyolefin resins such as polyvinyl methyl ether, polyamine, polyethyleneimine, casein, gelatin, starch and copolymers thereof, copolymer resins with polyethylene, polypropylene and other olefinic monomers, polyester resins, polyvinyl chloride resins , Polystyrene resins such as polystyrene and acrylonitrile-styrene copolymer resin, polymethyl methacrylate and (meth) acrylic Acrylic resins such as acid ester copolymers, acrylonitrile-methyl acrylate copolymers, polycarbonate resins, polyurethane resins, vinyl chloride-vinyl acetate copolymer resins, polyvinyl butyral resins and derivatives or modified products thereof, polyisobutylene, polytetrahydrofuran , Polyaniline, acrylonitrile-butadiene-styrene copolymer (ABS resin), polyamides such as nylon (registered trademark), polyimides, polydienes such as polyisoprene and polybutadiene, polysiloxanes such as polydimethylsiloxane, polysulfones, List polyimines, polyacetic anhydrides, polyureas, polysulfides, polyphosphazenes, polyketones, polyphenylenes, polyhaloolefins, and their derivatives It can be.
As the derivatives, those having the above-mentioned hydroxyl group, amino group, carboxyl group, epoxy group, vinyl group, thiol group, photocrosslinking group, and groups related to these combinations are preferable.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these Examples.

Example 1
[Preparation of lipophilic polyrotaxane]
To 500 mg of a hydroxypropylated polyrotaxane having a hydroxyl group modified with a hydroxypropyl group, 10 mL of ε-caprolactone dried with molecular sieves was added and allowed to permeate by stirring at room temperature for 30 minutes. Thereafter, 0.2 mL of tin 2-ethylhexanoate was added and reacted at 100 ° C. for 1 to 8 hours.
After completion of the reaction, the sample was dissolved in 50 mL of toluene, dropped into 450 mL of hexane which was stirred, precipitated and collected.

[Production of laminated coated steel sheet]
Cationic electrodeposition paint (trade name “Power Top U600M”, a cation type electrodeposition paint manufactured by Nippon Paint Co., Ltd.) is applied to a 0.8 mm thick, 70 mm × 150 mm thick dull steel sheet treated with zinc phosphate, resulting in a dry film thickness of 20 μm. Thus, after electrodeposition coating, it was baked at 160 ° C. for 30 minutes. Thereafter, a gray intermediate coat (trade name: Hyepico No. 560) manufactured by Nippon Oil & Fats Co., Ltd. was applied to 30 μm and baked at 140 ° C. for 30 minutes.
Next, the first layer (base coat coating layer) and the second layer (clear coating layer with good scratch resistance containing the lipophilic polyrotaxane described above) were applied to form a multilayer coating.

At this time, the first layer was spray-coated so that the dry film thickness was 10 μm, and the second layer was spray-coated so that the dry film thickness was 30 μm. Then, it baked at 140 degreeC for 30 minutes.
In addition, the following were used as a 1st layer coating material and a 2nd layer coating material (components other than lipophilic polyrotaxane).
First layer paint Solvent type black paint: Melamine curable acrylic paint “Bellcoat No. 6010” manufactured by Nippon Oil & Fats Co., Ltd.
Second layer paint The polyrotaxane obtained as described above was dissolved in toluene to 30%. Subsequently, Bell Coat No. The dissolved polyrotaxane was added to 6200GN1 acrylic / melamine curable clear paint with stirring, and the resulting solvent-type clear paint was used as the second layer paint.

[Formation of coating film defects]
During the second layer coating, coating was carried out with a foreign matter having a particle size of 500 μm attached to the surface of the second layer, and a laminated coated steel sheet having a coating film defect as shown in FIG. 1 was produced.

[Repair processing]
As shown in FIG. 1, the coating film defects were ground with sandpaper to form a ground portion.
Next, a conventional repair coating “Belcoat No. 6200 GN1” that does not contain polyrotaxane was applied to the ground portion to form a PR-free repair coating layer. Next, thinner was applied in the vicinity of the boundary between the PR-free repair coating layer and the second layer.

Further, the PR-containing repair coating layer was formed by applying the second layer coating material to the PR-free repair coating layer. In this application, the second layer coating was applied so that the PR-free repair coating layer did not protrude.
Subsequently, it heated at 140 degreeC for 30 minute (s), and formed the coating film layer for PR containing repair. Thereafter, the second layer was polished to remove the excess of the PR-containing repair coating layer, and the preparation of the repaired (finished) laminated coating film of this example was completed.

(Comparative Example 1)
A repaired (finished) laminated coating film of this example was produced by repeating the same operation as in Example 1 except that the second layer coating material containing no polyrotaxane was used.

[Performance evaluation]
The following characteristics evaluation was performed about the repair laminated coating film of each said example.

(Degree of disappearance of coating film defects)
The degree of disappearance of coating film defects was visually evaluated. The obtained results are shown in Table 1. In addition, the meaning of the symbol in Table 1 is as follows.
○: Scratches are not noticeable.
Δ: Some scratches are visible.
X: Many scratches are visible.

(Car wash resistance)
The repair laminated coating film of each example was washed five times using a car wash machine, and the degree of damage was visually evaluated. In addition, the meaning of the symbol in Table 1 is as follows.
○: Scratches are not noticeable.
Δ: Some scratches are visible.
X: Many scratches are visible.

  As is clear from the results in Table 1, in the repaired laminated coating film of Example 1 included in the scope of the present invention, defects in the coating film disappeared, and good appearance recovery and scratch resistance were compatible. .

It is sectional explanatory drawing which shows each process in the preparation method of the repair lamination coating film of this invention in steps. It is sectional explanatory drawing which shows each process in the other example of the preparation method of the repair lamination coating film of this invention in steps. It is a schematic diagram which shows notionally the basic structure of a polyrotaxane. It is a partial conceptual diagram which shows notionally the crosslinked structure of a polyrotaxane and resin.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Crosslinked polyrotaxane 3 Transparent resin 3 'Transparent resin 5 Polyrotaxane 6 Linear molecule 7 Cyclic molecule 8 Blocking group 9 Crosslinking point 10 Undercoat coating layer 20 Intermediate coating layer 30 Base coat layer 30
40 PR-containing topcoat layer 40
50 Coating defect 50 'Foreign object 52 Grinding part 54 Deep grinding part 60 PR-free repair coating layer 70 PR-containing repair coating layer 80 Repair base coat coating layer 100 Multi-layer coating 100R Repair multi-layer coating 110 Multi-layer coating Membrane 110R Repair laminated coating

Claims (12)

It is a repaired multilayer coating film comprising a base coating film layer and a PR-containing top coating film layer containing a lipophilic polyrotaxane or a hydrophilic polyrotaxane, and repairing the multilayer coating film having a coating film defect on the PR-containing top coating film layer. And
The PR-containing topcoat coating layer comprises a grinding part formed by grinding the coating film defect, a PR-free repair coating layer and a PR-containing repair coating layer sequentially laminated on the grinding part,
The PR-free repair coating layer is a coating layer formed from a PR-free repair top coating that does not contain a lipophilic polyrotaxane or a hydrophilic polyrotaxane,
The repair-laminated coating film, wherein the PR-containing repair coating layer is a coating layer formed from a PR-containing repair topcoat containing a lipophilic polyrotaxane or a hydrophilic polyrotaxane.   The lipophilic polyrotaxane or hydrophilic polyrotaxane contained in the PR-containing topcoat coating layer and the lipophilic polyrotaxane or hydrophilic polyrotaxane contained in the PR-containing repair coating layer are the same species. Item 2. The repair laminated coating film according to Item 1. A base coat film layer is added between the undercoat film layer and the PR-containing top coat film layer, and the ground portion reaches the base coat film layer,
In this deep grinding part, a repair base coat film layer having substantially the same components as the base coat film layer, a PR-free repair paint film layer, and a PR-containing repair paint film layer are sequentially laminated. The repair laminated coating film according to claim 1 or 2.   The repair coating film according to claim 3, wherein the base coat film layer contains a color pigment or a bright material.   The lipophilic polyrotaxane has a cyclic molecule, a linear molecule that includes the cyclic molecule in a skewered manner, and a blocking group that is disposed at both ends of the linear molecule and prevents the cyclic molecule from detaching. It has and functions as a solvent-type paint material, The repair lamination coating film as described in any one of Claims 1-4 characterized by the above-mentioned.   The repair laminated coating film according to claim 5, wherein the lipophilic polyrotaxane has a linear molecule and / or a cyclic molecule that is hydrophobic.   The hydrophilic polyrotaxane has a cyclic molecule, a linear molecule that includes the cyclic molecule in a skewered manner, and a blocking group that is disposed at both ends of the linear molecule and prevents the cyclic molecule from being detached. It has and functions as a water-system coating material, The repair lamination coating film as described in any one of Claims 1-4 characterized by the above-mentioned.   The repairing multilayer coating film according to claim 7, wherein the hydrophilic polyrotaxane has a linear molecule and / or a cyclic molecule that is hydrophilic. In preparing the repair laminated coating film according to any one of claims 1, 2, and 5-8,
Grind the coating film defect to form a grinding site,
Next, a method for producing a repaired multi-layer coating film, comprising: sequentially applying the PR-free repair topcoat and the PR-containing repair topcoat to the ground portion. In producing the repaired laminated coating film according to any one of claims 3 to 8,
Grind the coating film defects to form the deep grinding site,
Next, a repair base coat paint for forming the repair base coat film layer, the PR-free repair top coat, and the PR-containing repair top coat are sequentially applied to the deep ground portion. A method for producing a repaired laminated coating film.   11. The PR-free repair top coat is applied in a plurality of times, and at this time, the dilution ratio becomes higher as the PR-free repair top coat used for subsequent coating. Of repairing laminated coating film.   The method for producing a repaired multilayer coating film according to any one of claims 9 to 11, wherein the coating film defect is ground by polishing with a wax containing a compound.

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