JP5140047B2 - Curable solvent-based clear coating - Google Patents

Description

  The present invention relates to a curable solvent-based clear coating film, and more specifically, a product used in a field where particularly scratch resistance is required, mainly an automobile body; a resin molded product indoors and outdoors; a staircase, a floor It relates to a curable solvent-based clear coating that can be applied to woodwork products such as furniture, aluminum wheels and door mirrors that have been subjected to treatments such as plating, vapor deposition, and sputtering.

Conventionally, resin molded products such as polycarbonate and acrylic plates lack various physical properties such as hardness, weather resistance, stain resistance, and solvent resistance. Therefore, surface treatment is usually applied to supplement these physical properties.
As such a surface treatment, for example, a curable paint such as a normally dry paint or a two-component urethane paint is employed (see, for example, Patent Document 1).
However, the treatment film using the paint is easily scratched, and the scratch is easily noticeable.

Moreover, metal mirror surface treatments such as plating, vapor deposition, and sputtering are employed for design properties (see, for example, Patent Document 2).
However, when the metal mirror surface treatment is performed, the treatment film is easily scratched, and the scratch is easily noticeable. Usually, after the mirror treatment such as vapor deposition and sputtering, the surface treatment as described above is performed. However, the obtained treatment film is easily scratched, and the scratch is easily noticeable.

Furthermore, with regard to the top coat for automobiles, in recent years, the trend toward high durability has been strengthened so as to maintain the painted appearance of new cars for a long period of time. For this reason, there is a demand for scratch resistance that is not damaged by car wash machines, dust, stone splashes, or the like.
Conventionally known as scratch-resistant paints are ultraviolet (UV) curable paints, electron beam energy (EB) curable paints, silica-based hard coat agents, two-component acrylic urethane-based soft paints, and the like. (For example, refer to Patent Document 3).

JP 2004-131601 A JP 2003-293146 A Japanese Patent Publication No. 6-29382

  However, in the UV curable paint, EB curable paint, and silica-based hard coat agent, the use of a hard monomer for increasing the hardness and the increase in strain at the time of curing shrinkage by increasing the crosslink density, Problems such as poor adhesion and cracks are likely to occur.

  On the other hand, the above-mentioned two-component acrylic urethane-based soft paint has no problems of chipping and cracking, but often has a tacky feeling and has a disadvantage that it is inferior in weather resistance and stain resistance.

  The present invention has been made in view of such problems of the prior art, and the object thereof is a curable solvent that has excellent scratch resistance, chipping resistance, and is less prone to cracks. It is providing a system clear coating film and a laminated coating film using the same.

  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 lipophilic polyrotaxane in which a linear molecule or a cyclic molecule has a hydrophobic modifying group. The present invention has been completed.

That is, the curable solvent-based clear coating film of the present invention is a curable solvent-based clear coating film disposed on the surface of the coating film to be coated on the object to be coated,
Solidified curable solvent-based clear paint containing lipophilic polyrotaxane,
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. In addition, the linear molecule and / or the cyclic molecule has a (—CO (CH ₂ ) ₅ OH) group which is a modified group by caprolactone.

  The preferred form of the curable solvent-based clear coating film of the present invention is that the inclusion amount of the cyclic molecule in the lipophilic polyrotaxane is a maximum inclusion amount that is the maximum amount that the linear molecule includes the cyclic molecule. If it is 1, it is 0.06-0.61.

  Furthermore, another preferred embodiment of the curable solvent-based clear coating film of the present invention is characterized in that the lipophilic polyrotaxane is contained in an amount of 1 to 30% in terms of mass relative to the coating film forming component.

  Furthermore, in another preferred embodiment of the curable solvent-based clear coating film of the present invention, the curable solvent-based clear coating material further comprises at least one selected from the group consisting of an additive, a pigment, and a brightening agent. It contains a thing, a solvent, a resin component, and a hardening | curing agent.

On the other hand, the multilayer coating film of the present invention is a multilayer coating film comprising a curable solvent-based clear coating film as described above,
A base coat coating film is provided between the article to be coated and the curable solvent-based clear coating film.

  Moreover, the suitable form of the laminated coating film of this invention has an undercoat coating film between the said to-be-coated article and the said basecoat coating film.

  According to the present invention, the use of a lipophilic polyrotaxane in which linear molecules and cyclic molecules are provided with a hydrophobic modifying group has excellent scratch resistance, chipping resistance, and is hard to generate cracks. A type solvent-based clear coating film and a laminated coating film using the same can be provided.

It is a schematic diagram which shows notionally hydrophobic modification polyrotaxane. 1 is a schematic diagram conceptually showing a crosslinked polyrotaxane. It is a schematic sectional drawing which shows an example of the laminated coating film of this invention.

  Hereinafter, the curable solvent-based clear coating film of the present invention will be described in detail. In the present specification, “%” represents mass percentage unless otherwise specified.

As described above, the curable solvent-based clear coating film of the present invention is formed by solidifying a curable solvent-based clear paint containing a lipophilic polyrotaxane.
This lipophilic polyrotaxane has a cyclic molecule and a linear molecule having blocking groups at both ends. Further, the linear molecule includes the cyclic molecule by penetrating the opening of the cyclic molecule in a skewered manner, and further the elimination of the cyclic molecule in which the blocking groups arranged at both ends are included. Is preventing.
In addition, either one or both of the linear molecule and the cyclic molecule constituting the polyrotaxane have a hydrophobic modifying group.

FIG. 1 is a schematic diagram conceptually showing a hydrophobic modified polyrotaxane.
In this figure, this hydrophobic modified polyrotaxane 5 has a linear molecule 6, a cyclodextrin 7 which is a cyclic molecule, and blocking groups 8 arranged at both ends of the linear molecule 6. The molecule 6 penetrates through the opening of the cyclic molecule 7 and includes the cyclic molecule 7.
And the cyclodextrin 7 has the hydrophobic modification group 7a.

  By using such a lipophilic polyrotaxane, a coating material that is miscible with a hydrophobic solvent can be obtained. In addition, when applied to paint, the durability of the product is improved. In other words, it is effective because scratch resistance and chipping resistance are improved and other required performance is not adversely affected. Furthermore, it is excellent also in a weather resistance, contamination resistance, adhesiveness, etc.

Here, the linear molecule may be substantially linear, and has a branched chain as long as the cyclic molecule that is a rotor can rotate and can be included so as to exert a pulley effect. Also good.
Moreover, although it is influenced also by the magnitude | size of a cyclic molecule, the length is not specifically limited as long as a cyclic molecule can exhibit a pulley effect.

In the above lipophilic polyrotaxane, either one or both of the linear molecule and the cyclic molecule have a hydrophobic modifying group, which makes it soluble in an organic solvent.
Such expression of lipophilicity provides a reaction field, typically a crosslinking field, of an organic solvent to a polyrotaxane that has been hardly soluble or insoluble in an aqueous solvent or an organic solvent. That is, such a lipophilic polyrotaxane has improved reactivity that can be easily cross-linked with another polymer or modified with a modifying group in the presence of an organic solvent.

The 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 linear molecule is not particularly limited, and examples thereof include polyesters such as polyalkyls and polycaprolactone, polyethers, polyamides, polyacryls, and linear molecules having a benzene ring. it can.
Specific examples include polyethylene glycol, polyisoprene, polybutadiene, polypropylene glycol, polytetrahydrofuran, polydimethylsiloxane, polyethylene, and polypropylene. As such linear molecules, polyethylene glycol and polycaprolactone are particularly preferable.

The molecular weight of the linear molecule is desirably 1,000 to 35,000, preferably 10,000 to 35,000, and more preferably 20,000 to 35,000.
When the molecular weight is less than 1,000, the pulley effect is lowered, the elongation of the coating film is lowered, and the scratch resistance and chipping resistance may be lowered. If it exceeds 35,000, the solubility may be lowered, and the clear smoothness and glossy appearance may be lowered due to the film formation on the surface.

In addition, as said linear molecule, what has a reactive group in the both ends is preferable, and this enables it to react with the said blocking group easily.
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.

The cyclic molecule is not particularly limited as long as it is included in the linear molecule as described above and exhibits a pulley effect, and various cyclic substances can be exemplified. Many cyclic molecules have a hydroxyl group.
In addition, the cyclic molecule is sufficient if it is substantially cyclic, and includes those that are not completely closed, such as “C” shape.

The cyclic molecule preferably has a reactive group, which facilitates crosslinking with another polymer and bonding with a modifying group.
Such reactive groups can be appropriately changed, and examples thereof include a hydroxyl group, an amino group, a carboxyl group, a thiol group, and an aldehyde group.
The reactive group is preferably a group that does not react with the blocking group when a blocking group described later is formed (blocking reaction).

  Furthermore, specific examples of the cyclic molecule include various cyclodextrins such as α-cyclodextrin (glucose number: 6), β-cyclodextrin (glucose number: 7), 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.
In particular, α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin are preferable, and α-cyclodextrin is preferable from the viewpoint of inclusion.

Moreover, if a hydrophobic modifying group is introduced into the hydroxyl group of cyclodextrin, the solvent solubility of the lipophilic polyrotaxane can be further improved.
At this time, the degree of modification with the hydrophobic modifying group is preferably 0.02 or more, more preferably 0.04 or more, and 0 when the maximum number of cyclodextrin hydroxyl groups that can be modified is 1. More preferably, it is 0.06 or more.
If it is less than 0.02, the solubility in an organic solvent will not be sufficient, and insoluble bumps (protrusions derived from adhesion of foreign matter, etc.) may be generated.
Here, the maximum number that the hydroxyl groups of cyclodextrin can be modified is, in other words, the total number of hydroxyl groups that cyclodextrin had before modification. In other words, the degree of modification is the ratio of the number of modified hydroxyl groups to the total number of hydroxyl groups.
Although at least one hydrophobic group may be used, it is desirable to have one hydrophobic group for each cyclodextrin ring.
Further, by introducing a hydrophobic group having a functional group, the reactivity with other polymers can be improved.

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

In the above-mentioned lipophilic polyrotaxane, the number (inclusion amount) of the cyclic molecules included in the linear molecule is preferably 0.06 to 0.61 when the maximum inclusion amount is 1, and 0.11 -0.48 is still more preferable, and 0.24-0.41 is still more preferable.
If it is less than 0.06, the elongation effect of the coating film may decrease due to a decrease in the pulley effect. If it exceeds 0.61, the cyclic molecules may be arranged too densely and the mobility of the cyclic molecules may decrease, the elongation of the coating film may decrease, and the scratch resistance and chipping resistance may decrease. .

Further, the amount of inclusion of the cyclic molecule can be controlled as follows.
In the first method, DMF (dimethylformamide) is mixed with BOP reagent (benzotriazol-1-yl-oxy-tris (dimethylamino) phosphonium hexafluorophosphate), HOBt, adamantaneamine, and diisopropylethylamine in this order. Add to make 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.

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 maintain a state where the cyclic molecule is penetrated by the linear molecule in a skewered manner. .
Examples of such a group include a group having “bulkiness” or a group having “ionicity”. Further, the “group” here means various groups including a molecular group and a polymer group.

Examples of the “bulky” group include a spherical group 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, cyclodextrin groups, adamantane groups, trityl groups, fluorescein groups, and the like. Examples include pyrenes and derivatives or modified products thereof.

As described above, the lipophilic polyrotaxane is composed of a polyrotaxane having a hydrophobic modifying group, and the lipophilic polyrotaxane can be typically produced as follows.
(1) mixing a cyclic molecule with a linear molecule, penetrating through the opening of the cyclic molecule with a linear molecule in a skewered manner, and including the cyclic molecule in the linear molecule; (2) obtaining 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, and (3) a cyclic molecule of the obtained polyrotaxane. It is obtained by treating in the step of modifying the hydroxyl group possessed by a hydrophobic modifying group.
In the step (1), a hydrophobic modified polyrotaxane can also be obtained by using a cyclic molecule in which the hydroxyl group of the cyclic molecule is previously modified with a hydrophobic modifying group. (3) The process can be omitted.

By such a production method, a lipophilic polyrotaxane excellent in solubility in an organic solvent as described above 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, etc. Ethers, hydrocarbon solvents such as toluene and xylene, and the like. The lipophilic polyrotaxane exhibits good solubility even in a solvent in which two or more of these are mixed.

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.

Moreover, in this invention, it is desirable from a viewpoint that all or one part of a hydrophobic modification group has a functional group from the viewpoint of improving the reactivity with another polymer.
Such a functional group is preferably located outside the cyclodextrin in terms of a three-dimensional structure, and can be easily reacted with the functional group when bonded or crosslinked with a polymer.

Such a functional group can be appropriately changed according to, for example, the type of solvent used when a crosslinking agent is not used. On the other hand, when using a crosslinking agent, it can change suitably according to the kind of the crosslinking agent to be used.
Furthermore, in the present invention, specific examples of the functional group may include, for example, a hydroxyl group, a carboxyl group, an amino group, an epoxy group, an isocyanate group, a thiol group, and an aldehyde group, but are not limited thereto. .

And in a hydrophobic modification polyrotaxane, the above-mentioned functional group may have the 1 type individually or in combination of 2 or more types.
Such functional groups are particularly residues of compounds bonded to the hydroxyl group of cyclodextrin, and those having a hydroxyl group, a carboxyl group, an amino group, an epoxy group, or an isocyanate group are good, and there are various reactions. From the viewpoint of properties, a hydroxyl group is preferred.
Examples of the compound that forms such a functional group include propylene oxide, but are not limited thereto.
For example, if the effect of improving the solubility of the hydrophobic modified polyrotaxane in an organic solvent is not significantly reduced, the compound forming the functional group may be a polymer. From the viewpoint of solubility, for example, the molecular weight is several thousand. It is desirable that the degree.
The above-mentioned functional group is preferably a group that reacts under reaction conditions in which a blocking group described later does not leave.

Next, the curable solvent-based clear paint used for the curable solvent-based clear coating film of the present invention will be described in detail.
This curable solvent-based clear paint contains the above-described lipophilic polyrotaxane. The curable solvent-based clear coating film of the present invention is formed by solidifying the curable solvent-based clear coating.

  As a result, at the time of coating film formation, the hydrophobic modifying group and other functional groups possessed by the lipophilic polyrotaxane react with the coating film forming component to form a crosslinked polyrotaxane, thereby improving scratch resistance and chipping resistance. Become better. In addition, cracks are not easily generated. Furthermore, it is excellent also in a weather resistance, contamination resistance, adhesiveness, etc.

  In general, a crosslinked polyrotaxane refers to a crosslinked polyrotaxane and another polymer, and at the time of coating film formation, the above-described lipophilic polyrotaxane is crosslinked with a film-forming component (such as a polymer). is there. This coating film-forming component is bonded to the polyrotaxane via the polyrotaxane cyclic molecule.

Hereinafter, the crosslinked polyrotaxane will be described.
FIG. 2 conceptually shows the crosslinked polyrotaxane.
In this figure, the crosslinked polyrotaxane 1 has a polymer 3 and the lipophilic polyrotaxane 5. And this polyrotaxane 5 is couple | bonded with the polymer 3 and the polymer 3 'by the crosslinking point 9 through the cyclic molecule 7. FIG.

When a deformation stress in the direction of arrow XX ′ in FIG. 2A is applied to the crosslinked polyrotaxane 1 having such a configuration, the crosslinked polyrotaxane 1 is deformed as shown in FIG. 2B. This stress can be absorbed.
That is, as shown in FIG. 2B, the cyclic molecule 7 can move along the linear molecule 6 due to the pulley effect, so that the stress can be absorbed therein.

Thus, the crosslinked polyrotaxane has a pulley effect as shown in the figure, and has excellent stretchability, viscoelasticity, and mechanical strength as compared with a conventional gel-like material.
Further, the lipophilic polyrotaxane, which is a precursor of the crosslinked polyrotaxane, has improved solubility in an organic solvent as described above, and is easily crosslinked in an organic solvent.

Therefore, the crosslinked polyrotaxane can be easily obtained under conditions where an organic solvent is present, and can be easily produced by crosslinking a lipophilic polyrotaxane and an organic solvent-soluble coating film-forming component.
Accordingly, the above-mentioned lipophilic polyrotaxane has an expanded range of applications, for example, paints and adhesives using a coating film soluble in an organic solvent, particularly car wash resistance, scratch resistance, chipping resistance, It can also be applied to paints for automobiles, resin base materials and adhesives that require impact and weather resistance, and paints and resin base materials for home appliances, and can exhibit excellent pulley effects in these applications. Is.

From another point of view, the crosslinked polyrotaxane is a composite of the coating film-forming component and the polyrotaxane without impairing the physical properties of the coating film-forming component that is an object of crosslinking of the lipophilic polyrotaxane.
Therefore, according to the method for forming a crosslinked polyrotaxane described below, a material having both the physical properties of the coating film forming component and the lipophilic polyrotaxane itself can be obtained. It is possible to obtain a coating film having a mechanical strength of
Note that the crosslinked polyrotaxane is soluble in an organic solvent if the crosslinking target is hydrophobic and the molecular weight is not so large, for example, if the molecular weight is up to about several thousand.

Here, a method for forming a crosslinked polyrotaxane will be described.
The cross-linked polyrotaxane is typically (a) a lipophilic polyrotaxane mixed with another film-forming component, (b) at least a part of the film-forming component is physically and / or chemically cross-linked, (C) It can be formed by bonding at least a part of the coating film-forming component and a lipophilic polyrotaxane via a cyclic molecule (curing reaction).
In addition, since lipophilic polyrotaxane is soluble in the organic solvent, the (a) process-(c) process can be performed smoothly in an organic solvent. 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 cyclic molecule of the lipophilic polyrotaxane as described above and the polyisocyanate compound which is an example of the paint forming component are urethane. By repeatedly forming bonds, a crosslinked polyrotaxane is obtained. 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 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.

Moreover, it is preferable that the said clear coating material is contained 1-30% in conversion of mass with respect to a coating-film formation component (resin solid content etc.). More preferably, it is 10 to 30%, and particularly preferably 20 to 30%.
If it is less than 1%, the pulley effect may be reduced and the elongation of the coating film may be reduced. If it exceeds 30%, the appearance such as smoothness and gloss may be deteriorated due to surface film formation.

  Further, the clear paint is preferably formed by mixing at least one selected from the group consisting of an additive, a pigment and a brightening agent, a solvent, a resin component, and a curing agent in a lipophilic polyrotaxane. .

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.

Two or more kinds of resin components may be mixed and used. In this case, it is preferable that at least one kind of resin component is bonded to the polyrotaxane via a 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.

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.

  Specific examples of the additive include a dispersant, an ultraviolet absorber, a light stabilizer, a surface conditioner, and a crack inhibitor.

  Specific examples of the pigment include organic color pigments such as azo pigments, phthalocyanine pigments, and perylene pigments, and inorganic color pigments such as carbon black, titanium dioxide, and bengara.

  Specific examples of the brightening agent include aluminum pigments and mica pigments.

  Specific examples of the solvent include esters such as ethyl acetate, butyl acetate and isobutyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ethers such as diethyl ether and dioxane, toluene and xylene, Hydrocarbon solvents such as Solvesso or long-chain alcohols with high hydrophobicity can be used. Two or more of these may be mixed as appropriate. Moreover, even if some aqueous solvents, such as water and a butyl cellosolve acetate, are contained, it should just be considered as an organic solvent as a whole.

Furthermore, the above clear paint can form a general clear coating film as a transparent clear paint, and also a so-called turbid clear coating film or matte clear coating film that imparts a semi-transparent feeling as a turbid clear paint or matte clear paint. Can be formed.
Although it does not specifically limit as a film thickness of the coating film which these clear paints form, About 20-40 micrometers is preferable.

Furthermore, the clear paint can be a turbid clear paint or a matte paint.
In order to obtain the turbid clear paint or matte clear paint, a matting agent such as silica or resin beads may be added in addition to the above components.

  The properties of the clear paint include solvent type such as general enamel paint, curable solvent type such as acrylic melamine paint and acid-epoxy paint, two-component type such as urethane resin paint, and epoxy paint. .

Next, the laminated coating film of the present invention will be described in detail.
The laminated coating film of the present invention is formed by sequentially forming a base coat film and the above-mentioned curable solvent-based clear coating film on an object to be coated.

  This improves the scratch resistance and chipping resistance of the laminated coating film.

  The lipophilic liquid may be a one-pack type, a two-pack type (for example, urethane resin paint) or the like, or a lacquer or photo-curing resin.

Examples of the article to be coated typically include various metal materials such as iron, aluminum and copper, various organic materials such as polypropylene and polycarbonate, and various inorganic materials such as quartz and ceramics (calcium carbide, etc.).
Moreover, as a method of coating these with solvent-based clear paint, a known and commonly used method can be employed. For example, a brush coating method, a spraying method, an electrostatic coating method, an electrodeposition coating method, a powder coating, and a sputtering method can be used.
Furthermore, the solvent-based clear paint can be typically formed into a coating film by heat curing (baking) treatment.
In addition, the said solvent-type clear coating material can coat | cover the whole to-be-coated article or a part.

  In the laminated coating film of the present invention, it is preferable to further form an undercoat film and a base coat film between the article to be coated and the clear film. In this case, a cross-linked structure with a lipophilic polyrotaxane can be formed at the interface with the base coat film, which is effective.

An example (schematic cross section) of the above-described laminated coating film of the present invention is shown in FIG.
As for this laminated coating film, the undercoat coating film 10, the base coat 11, and the clear coating film 12 are provided in order.
The solvent-based clear paint is not limited to forming a single layer, and can be used for forming a plurality of layers.

  EXAMPLES Hereinafter, although a specific Example is given and this invention is demonstrated in detail, this invention is not limited by a following example.

Example 1
1. Synthesis of Modified Polyrotaxane 10 mL of ε-caprolactone dried with molecular sieves was added to 500 mg of hydroxypropylated polyrotaxane having a hydroxyl group modified with a hydroxypropyl group, and the mixture was 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.

2. Preparation of clear paint The obtained polyrotaxane was dissolved in toluene so as to be 10%.
Subsequently, Bell Coat No. The dissolved polyrotaxane was added to 6200GN1 acrylic / melamine curable clear paint with stirring.

3. Formation of multi-layer coating film Cathodic electrodeposition paint (trade name “Power Top U600M”, cation-type electrodeposition paint manufactured by Nippon Paint Co., Ltd.) is applied to a 0.8 mm thick, 70 mm × 150 mm thick steel plate treated with zinc phosphate. After electrodeposition coating so that the thickness was 20 μm, baking was performed at 160 ° C. for 30 minutes.
Thereafter, a gray undercoat (trade name: Hyepico No. 500) manufactured by Nippon Oil & Fats Co., Ltd. was applied with 30 μm and baked at 140 ° C. for 30 minutes.

  Next, 10 μm of Bell Coat No 6010 metallic coating color manufactured by Nippon Oil & Fats Co., Ltd. was applied, 30 μm of a clear paint containing polyrotaxane was applied by wet on wet, and baked at 140 ° C. for 30 minutes.

(Examples 2-11, Comparative Examples 1-3)
A laminated coating film was formed by repeating the same operation as in Example 1 except that the specifications shown in Table 1 were adopted.

  About the obtained laminated coating film, the following (1)-(5) evaluation was performed.

(1) Solubility The clear turbidity obtained in Step 2 was mixed, and the white turbidity when applied to a glass plate was visually evaluated.
○: No change △: Slight cloudiness ×: Cloudiness and separation

(2) Smoothness The degree of smoothness of the clear coating film in the laminated coating film obtained in step 3 was visually evaluated.
◯: Pretty smooth Δ: Slightly uneven ×: Uneven

(3) Scratch resistance A dust coat (friction cloth) is attached to a slider of an abrasion tester with a double-sided tape, and the clear coating film in the laminated coating film obtained in step 3 under a load of 0.22 g / cm ^2. Was reciprocated 50 times to evaluate the presence or absence of scratches.
○: There is almost no scratch.
Δ: Slightly scratched
X: There are many scratches so as to be conspicuous.

(4) Reactivity The product obtained in Step 1 and hexamethylene diisocyanate were mixed in an equivalent ratio, and baked and dried at 140 ° C. for 30 minutes. Judgment was made by the presence or absence of a urethane bond by the infrared absorption spectrum of the coating film.
○: Urethane bond present ×: No urethane bond present

(5) Weather resistance About the clear coating film in the laminated coating film obtained in step 3, a xenon weather meter (XWM) was tested for 1440 hours to measure the color difference (ΔE).
○: △ E ≦ 3
Δ: 3 <ΔE ≦ 5
×: ΔE> 5

As is clear from the results of Table 1, the enamel coating in the laminated coatings of Examples 1 to 8, which is a preferred embodiment of the present invention, is recognized to have improved scratch resistance due to the pulley effect of the crosslinked polyrotaxane, It can be seen that the solubility, smoothness, pigment sedimentation, reactivity, and weather resistance are also good.
Further, as in Example 9, it can be seen that when the molecular weight of the linear molecule is less than 1000, the scratch resistance is lowered. Furthermore, as in Example 10, when it exceeds 35000, it can be seen that the smoothness and weather resistance deteriorate.
Further, as in Example 11, when the amount of the lipophilic polyrotaxane added to the coating exceeds 30%, the solubility, smoothness, and weather resistance are decreased.

  On the other hand, as in Comparative Examples 1 to 3, when no lipophilic polyrotaxane is used, it is understood that the effect of scratch resistance cannot be obtained.

  As described above, according to the present invention, the desired appearance can be obtained with the same workability as that of normal coating without being limited to the specified narrow coating conditions, and the scratch resistance of the clear coating film is improved. Is possible.

1 Crosslinked polyrotaxane 3, 3 ′ polymer 5 Hydrophobic modified polyrotaxane 6 Linear molecule 7 Cyclic molecule (cyclodextrin)
7a Hydrophobic modifying group 8 Blocking group 9 Cross-linking point 10 Undercoat film 11 Base coat film 12 Clear film

Claims (9)

A curable solvent-based clear coating film disposed on the surface of a coating film to be coated,
Solidified curable solvent-based clear paint containing lipophilic polyrotaxane,
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. A curable solvent-based clear coating film, wherein the linear molecule and / or the cyclic molecule has a (—CO (CH ₂ ) ₅ OH) group which is a modified group by caprolactone.   The inclusion amount of the cyclic molecule in the lipophilic polyrotaxane is 0.06 to 0.61 when the maximum inclusion amount, which is the maximum amount that the linear molecule includes the cyclic molecule, is 1. The curable solvent-based clear coating film according to claim 1.   3. The curable solvent-based clear coating film according to claim 1, wherein the linear molecule of the lipophilic polyrotaxane is polyethylene glycol and / or polycaprolactone.   The cyclic molecule of the lipophilic polyrotaxane is at least one cyclodextrin selected from the group consisting of α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin. The curable solvent-based clear coating film according to one item.   The curable solvent-based clear coating film according to any one of claims 1 to 4, wherein the lipophilic polyrotaxane is contained in an amount of 1 to 30% in terms of mass with respect to the coating film forming component.   The curable solvent-based clear paint further comprises at least one selected from the group consisting of an additive, a pigment, and a brightening agent, a solvent, a resin component, and a curing agent. The curable solvent-based clear coating film according to any one of 1 to 5.   The curable solvent-based clear paint according to any one of claims 1 to 6, wherein the curable solvent-based clear paint is a transparent clear paint, a turbid clear paint, or a matte clear paint. A laminated coating film comprising the curable solvent-based clear coating film according to any one of claims 1 to 7,
A laminated coating film comprising a base coat film between the object to be coated and the curable solvent-based clear coating film.   The laminated coating film according to claim 8, further comprising an undercoat coating film between the article to be coated and the base coat coating film.

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