JP2008161856A - Formation method and coating molded article of coating layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method which is excellent in antifouling property under an elevated temperature, and can form a coating layer simply and at a low cost. <P>SOLUTION: In the method of forming the coating layer 2 on the surface of a substrate 1, the coating layer is formed by preparing a plurality of types of coating liquids containing polysilazane and an acrylic resin with a mixture ratio of the polysilazane and the acrylic resin to be changed, and recoating the surface of the substrate successively a plurality of times from the coating liquid having a high mixture ratio of the acrylic resin while replacing the plurality of types of the coating liquids. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention mainly relates to a method for forming a coating layer on the surface of a resin substrate and a coating molded article having the coating layer formed thereon.

As a method for forming a coating layer for the purpose of preventing contamination on the surface of a substrate such as a resin substrate and a coating molded product, various types have been known or proposed (see, for example, Patent Documents 1 to 4). ).
Japanese Patent Laid-Open No. 7-305029 JP 2000-73012 A JP 2002-105676 A JP 2003-347294 A

However, the conventional method for forming a coating layer and the coating molded product as described above exhibit excellent antifouling properties when the medium to be contacted is a relatively low temperature material of about room temperature. If they are in contact with each other, there is a problem that the medium becomes a stain and remains for a long period of time, and the appearance of the substrate is remarkably deteriorated. Examples of this type of problem include curry stains on tableware and yellowing on bathtubs.
The present invention has been made in view of the above problems, and provides a method capable of forming a coating layer easily and at low cost with excellent antifouling properties at high temperatures, and a coating molded product that hardly causes residual contamination. With the goal.

In order to achieve the above object, the invention according to claim 1 is a method of forming a coating layer on the surface of a substrate, wherein the coating liquid containing polysilazane and acrylic resin is used as the polysilazane and acrylic resin. A plurality of types prepared by changing the mixing ratio, and in order from the coating liquid having a high mixing ratio of the acrylic resin, while replacing the plurality of types of coating liquid, repeatedly applied to the surface of the base material a plurality of times, In this method, a coating layer is formed.
In the present invention, various forms can be adopted as the form of applying the coating liquid. For example, in addition to hand-painting with a brush and machine-coating with a machine, electrostatic coating or spraying or spraying is also possible.

The second coating liquid that contains the acrylic resin and does not contain the polysilazane, and the third coating liquid that contains the polysilazane and does not contain the acrylic resin as described in claim 2, After the second coating solution is applied to the surface, the coating solution may be applied once or a plurality of times, and finally the third coating solution may be applied again.
The coating molded product obtained by this method has a composition in which the coating contains an acrylic resin and does not contain polysilazane on the surface side of the substrate, and has a composition that contains polysilazane on the surface of the coating layer and does not contain an acrylic resin.

Further, as described in claim 3, when the previously applied coating liquid or the second coating liquid is in a semi-dried state, the next coating liquid may be applied repeatedly.
By doing in this way, the composition change of a coating layer can be approximated to the shape of a straight line or a gentle curve.
Furthermore, as described in claim 4, in the step of applying the coating liquid, the second coating liquid, or the third coating liquid, at least one of the respective application steps includes a baking step after application. Also good. For example, after the coating liquid is applied and the coating liquid is dried, the substrate may be put into an oven or the like and fired at a predetermined temperature, or after the coating liquid is applied several times, You may make it perform baking.
In the present invention, at least one of the plurality of coating liquids, the second coating liquid, and the third coating liquid may contain silica nanoparticles.

According to another method of the present invention, there is provided a method for forming a coating layer on a surface of a substrate as described in claim 5, wherein (i) an acrylic resin coating solution not containing polysilazane and a polysilazane not containing an acrylic resin And (ii) applying the acrylic resin coating liquid to the surface of the base material,
(iii) Immediately after applying the acrylic resin coating liquid or before the acrylic resin coating liquid is dried, the polysilazane-containing coating liquid is applied over the acrylic resin coating liquid, and (iv) the polysilazane-containing liquid is applied. Immediately after the coating liquid is applied or before the polysilazane-containing coating liquid is dried, the acrylic resin coating liquid is reduced in concentration and applied over the polysilazane-containing coating liquid, and (v) the acrylic resin coating liquid. Immediately after coating or before the acrylic resin coating liquid dries, the polysilazane-containing coating liquid is increased in concentration and applied over the acrylic resin coating liquid. (Vi) (iv) and (v ), The acrylic resin coating While lowering the concentration in the liquid, repeated once or more times while increasing the concentration of the polysilazane-containing coating solution, finally, it is a method of coating the polysilazane-containing coating solution.

After performing the steps (i) to (vi) once, the polysilazane-containing coating solution may be finally applied, or after performing the steps (i) to (vi) once ( Steps iv) and (v) may be repeated once or a plurality of times, and finally the polysilazane-containing coating solution may be applied.
In this case, at least one of the polysilazane-containing coating liquid and the acrylic resin coating liquid may contain silica nanoparticles.
Also in this method, as described in claim 6, in the step of applying the polysilazane-containing coating solution after applying the acrylic resin coating solution, at least one of the applying steps is a baking step after application It may have.
As the coating layer formed on the surface of the substrate by the method of the present invention, a coating layer having an appropriate composition is used according to the application of the coating molded product and the usage environment. For example, when the coating molding is tableware, the ratio (wt% ratio) of polysilazane and acrylic resin in the coating liquid is 1.2 to 2.0 (1.2), as described in claim 7. 2.0 or less, the interpretation of “to” representing the numerical range in this specification is the same in the following) to form a lower layer portion of the coating layer, and 0.66 to 1.6 A coating layer is prepared to form the middle layer portion of the coating layer, and a coating layer within the range of 0.4 to 0.66 is prepared to form the upper layer portion of the coating layer. The ratio of the system resin is 1.2 to 2.0 in the lower layer portion of the coating layer, 0.66 to 1.6 in the middle layer portion, and 0.4 to 0.66 in the upper layer portion. Preferably within range There.

The molded product of the present invention is a coated molded product in which a coating layer is formed on the surface of a base material as described in claim 8, and the polysilazane is formed from the surface of the base material to the surface of the coating layer. The mixing ratio with the acrylic resin is gradually changed.
In this case, as described in claim 9, the coating layer may not include polysilazane on the surface of the base material, and the coating layer may not include the acrylic resin on the surface of the coating layer. Good.
The ratio (wt% ratio) of the acrylic resin to polysilazane in the coating liquid is selected appropriately depending on the application and use environment of the coating molded product. For example, when the coating molded product is tableware, the lower layer portion of the coating layer is within the range of 1.2 to 2.0, the middle layer portion is within the range of 0.66 to 1.6, and the upper layer portion is 0.00. It is preferable to be within the range of 4 to 0.66 (wt%).
In addition, the concept of the coating molding of this invention is shown in FIG.

  ADVANTAGE OF THE INVENTION According to this invention, the formation method and coating molding of a coating layer which are excellent in antifouling property at high temperature can be obtained.

Hereinafter, a suitable embodiment of a modeling method of the present invention is described in detail, referring to drawings.
[Base material]
The substrate to which the present invention can be applied is mainly a resin substrate.
Examples of the resin base material to which the present invention is applied include a resin molded body formed entirely of resin, and a resin-coated molded body made of a base material such as glass (ceramic), metal, or wood whose surface is resin-coated. be able to. As these molded products, for example, a bathtub used around the bathroom, an apron for the bathtub, a bathroom wall (bathroom wall), a bathroom counter, a washing place (waterproof pan), a wash counter, a wash bowl, a kitchen used around the kitchen It includes molded articles in a wide range of fields such as counters, panel members for kitchen cabinets (such as side panel panels, bottom panel panels, back panel panels, etc.), tableware, wall and flooring or dishwashers, sanitary products, automobile parts and the like.

[Polysilazane]
As the polysilazane, various known or commercially available products can be used.
For example, as disclosed in JP-A-7-305029, the general formula (I) is mainly used.

（但し、Ｒ¹ ，Ｒ² ，Ｒ³ はそれぞれ独立に水素原子、アルキル基、アルケニル基、シクロアルキル基、アリール基、またはこれらの基以外でケイ素に直結する基が炭素である基、アルキルシリル基、アルキルアミノ基、アルコキシ基を表わす。ただし、Ｒ¹ ，Ｒ² ，Ｒ³ のうち少なくとも１つは水素原子である。）で表わされる単位からなる主骨格を有する数平均分子量が１００〜５万のポリシラザンを挙げることができる。
また、例えば、特開２０００−０７３０１２号公報に記載されているものとして、

(However, R ¹ , R ² and R ³ are each independently a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, or a group in which the group directly connected to silicon other than these groups is carbon, alkylsilyl A group, an alkylamino group, an alkoxy group, provided that at least one of R ¹ , R ² , and R ³ is a hydrogen atom). Ten thousand polysilazanes can be mentioned.
Further, for example, as described in JP 2000-073012 A,

上記一般式（１）で表されるシラザン構造を分子鎖中に含有する数平均分子量が１００〜１００，０００のアミン残基含有ポリシラザン、上記一般式（２）で表されるシラザン構造を有するポリシラザン、上記一般式（３）で表されるシラザン構造を有するポリシラザンを挙げることができる。
上記のポリシラザンを溶解した溶液としては、市販のもの、例えばＡＺエレクトロニックマテリアルズ株式会社製のアクアミカ（登録商標）、ＮＬ１１０Ａシリーズを用いることができる。

An amine residue-containing polysilazane having a number average molecular weight of 100 to 100,000 containing the silazane structure represented by the general formula (1) in the molecular chain, and a polysilazane having a silazane structure represented by the general formula (2) And polysilazane having a silazane structure represented by the general formula (3).
As a solution in which the above polysilazane is dissolved, commercially available products such as Aquamica (registered trademark) NL110A series manufactured by AZ Electronic Materials Co., Ltd. can be used.

[Acrylic resin]
Known or commercially available acrylic resins can be used. For example, in the above-mentioned JP-A-7-305029, an acrylic resin is used as an acrylic resin (the alcohol residue includes methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group). , T-butyl group, 2-ethylhexyl group, cyclohexyl group, phenyl group, benzyl group, phenylethyl group and the like); methacrylate ester (alcohol residue is the same as above); 2-hydroxyethyl acrylate, 2- Hydroxy-containing monomers such as hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate; acrylamide, methacrylamide, N-methyl methacrylamide, N-methyl acrylamide, N-methylol acrylamide, N-methylol Amyl group-containing monomers such as clinamide, N, N-dimethylolacrylamide, N-methoxymethylacrylamide, N-methoxymethylmethacrylamide, N-phenylacrylamide; N, N-diethylaminoethyl acrylate, N, N-diethylaminoethyl methacrylate Amino group-containing monomers such as glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether and the like epoxy group-containing monomers; styrene sulfonic acid, vinyl sulfonic acid, and salts thereof (for example, sodium salt, potassium salt, ammonium salt, etc.) A monomer containing a sulfonic acid group or a salt thereof such as crotonic acid, itaconic acid, acrylic acid, maleic acid, fumaric acid, and salts thereof (for example, sodium salt, potassium salt, ammonium salt) A monomer containing a carboxyl group such as an um salt) or a salt thereof; a monomer containing an anhydride such as maleic anhydride or itaconic anhydride; other vinyl isocyanate, allyl isocyanate, styrene, vinyl methyl ether, vinyl ethyl ether, Made from a combination of monomers such as vinyltrisalkoxysilane, alkylmaleic acid monoester, alkyl fumaric acid monoester, acrylonitrile, methacrylonitrile, alkylitaconic acid monoester, vinylidene chloride, vinyl acetate, vinyl chloride Illustrated. As a commercially available product, for example, BR71 and BR80 manufactured by Mitsubishi Rayon can be used.
In the present invention, a UV (ultraviolet) curable acrylic resin may be used.

[Coating solution]
Examples of the solvent that can dissolve the polysilazane and the acrylic resin include xylene and toluene.
A solution in which polysilazane and acrylic resin are dissolved in the solvent is prepared, and the solutions are mixed at an appropriate ratio to prepare a plurality of types of coating liquids having different mixing ratios. Alternatively, polysilazane and acrylic resin may be dissolved in a solvent at a predetermined mixing ratio in advance, and a plurality of coating liquids may be formed at different mixing ratios.
In this embodiment, the acrylic resin-containing coating liquid (second coating liquid) that does not contain polysilazane and contains an acrylic resin, and the polysilazane-containing coating liquid (third coating liquid) that does not contain an acrylic resin and contains polysilazane. These are mixed at an appropriate mixing ratio to prepare a coating solution containing both polysilazane and acrylic resin. The amount of polysilazane contained in this coating solution is preferably in the range of 3 to 15 wt%. Moreover, it is preferable that the quantity of acrylic resin contained in this coating liquid shall be in the range of 15-3 wt%.
Examples of changes in the mixing ratio of polysilazane and acrylic resin contained in the coating liquid are shown in Table 1 below.

[filler]
In the present invention, although not essential, an appropriate filler may be added as necessary. Examples of the filler include fine oxides of oxide inorganic substances such as silica, alumina, zirconia and mica, or non-oxide inorganic substances such as silicon carbide and silicon nitride. Depending on the application, metal powders such as aluminum, zinc and copper can be added. In more detail, examples of fillers include silica sand, quartz, novaculite, diatomaceous earth, etc .: synthetic amorphous silica: kaolinite, mica, talc, wollastonite, asbestos, calcium silicate, aluminum silicate Silicates such as: glass powder, glass spheres, hollow glass spheres, glass flakes, foam glass spheres and other glass bodies: boron nitride, boron carbide, aluminum nitride, aluminum carbide, silicon nitride, silicon carbide, titanium boride, nitriding Non-oxide inorganic materials such as titanium and titanium carbide: Calcium carbonate: Metal oxides such as zinc oxide, alumina, magnesia, titanium oxide, and beryllium oxide: Barium sulfate, molybdenum disulfide, tungsten disulfide, carbon fluoride and other inorganic materials: Metal powder such as aluminum, bronze, lead, stainless steel, zinc: carbon Black, coke, graphite, pyrolytic carbon, carbon and the like of the hollow carbon spheres and the like. Moreover, you may add a pigment | dye suitably.

[Silica nanoparticles]
An advantage of adding silica nanoparticles as a filler is that it suppresses volume shrinkage when polysilazane is converted to SiO ₂ .
As silica nanoparticles, those having an average particle diameter of nm to 50 nm can be used. Moreover, what melt | dissolved the solvent soluble silica nanoparticle in solvents, such as toluene, is well-known or marketed.

[First Embodiment of Coating Layer Formation]
As shown in No. 1 to No. 3 in Table 1 above, a plurality of coating solutions containing polysilazane and acrylic resin and changing the mixing ratio are prepared.
And it apply | coats to the surface of the base material which performed the pre-processing of degreasing in an order from the thing with the high mixed density of acrylic resin. For example, in the coating liquid as shown in Table 1, the coating is performed in the order of No1, No2, and No3.
Each time the applied coating solution is completely dried, the next coating solution may be applied repeatedly. However, when the applied coating solution is in a semi-dry state, the next coating solution may be applied.
By recoating like the former, the coating composition (composition ratio of acrylic resin and polysilazane) forming the coating layer changes stepwise from the substrate side.
By applying the coating liquid in a semi-dry state like the latter, the two kinds of coating liquids are mixed in the vicinity of the boundary surface, and the change in the composition ratio in the coating layer can be brought close to a substantially linear shape or a gentle curved shape.
After all the coating liquids that have been planned have been applied, the coating layer is completed by leaving it to stand for a certain period of time, for example, at room temperature, followed by natural drying.

[Second Embodiment of Coating Layer Formation]
One type of coating liquid containing polysilazane and acrylic resin in a predetermined mixing ratio, or a plurality of coating liquids containing polysilazane and acrylic resin as shown in No. 1 to No. 3 in Table 1 and changing the mixing ratio Prepare. Furthermore, an acrylic resin-containing coating liquid (second coating liquid) that contains an acrylic resin and does not contain polysilazane, and a polysilazane-containing coating liquid (third coating liquid) that contains polysilazane and does not contain an acrylic resin are prepared.
And the 2nd coating liquid is apply | coated to the surface of the base material which gave pretreatments, such as degreasing, and then the coating liquid containing both polysilazane and acrylic resin is apply | coated. When a plurality of coating liquids are applied several times, as in the previous embodiment, the coating liquids are applied in order from the one having the higher acrylic resin mixed concentration.
Finally, a third coating solution is applied. Thereafter, it is naturally dried at room temperature, for example, to complete the coating layer. Also in this embodiment, the next coating liquid may be reapplied every time the applied coating liquid is completely dried, or the next coating liquid may be applied when the applied coating liquid is in a semi-dry state. It may be.
In this embodiment, the lowermost coating composition of the coating layer does not include polysilazane, and the uppermost coating composition does not include an acrylic resin.

[Third embodiment of coating layer formation]
The coating liquids prepared in this embodiment are a plurality of polysilazane-containing coating liquids having different concentrations and a plurality of acrylic resin-containing coating liquids having different concentrations. And after apply | coating the said acrylic resin coating liquid with the highest density | concentration among the said some acrylic resin containing coating liquid to the surface of the said base material, before this acrylic resin coating liquid dries, ie, a semi-dry state. Sometimes, the polysilazane-containing coating liquid having the lowest concentration is repeatedly applied among the plurality of polysilazane-containing coating liquids.
After this, when in a semi-dry state, apply an acrylic resin coating solution with a lower concentration than the first applied acrylic resin coating solution, and apply a polysilazane-containing coating solution with a higher concentration than the first applied polysilazane-containing coating solution. To do. In this way, the acrylic resin coating liquid and the polysilazane-containing coating liquid are alternately applied while changing the concentrations of the acrylic resin coating liquid and the polysilazane-containing coating liquid. Finally, the polysilazane-containing coating solution having the highest concentration is applied. Thereafter, it is naturally dried at room temperature, for example, to complete the coating layer.
In this embodiment, the lowermost coating composition of the coating layer contains little polysilazane, and the uppermost coating composition contains little acrylic resin.
In the first to third embodiments, it is also possible to color the coated molded article using a coating liquid appropriately added with a pigment.

[Baking]
The substrate on which the coating layer has been completed by the above procedure is baked in an oven or the like as necessary.
Moreover, you may make it perform baking once or several times in the middle of formation of a coating layer. In this case, the coating liquid may be dried each time it is applied, and the base material may be placed in an oven and fired. Moreover, after apply | coating a coating liquid in multiple times, you may make it dry by performing drying, putting a base material in oven.

  The conceptual diagram of the coating molding formed through the said process is shown in FIG. In FIG. 1, the left side is a configuration diagram (part) of a base material and a coating layer, and the right side is a graph showing an ideal change in the concentration ratio of an acrylic resin and polysilazane. As shown in the drawing, the concentration ratio of the acrylic resin increases as it approaches the surface of the substrate 1, and the concentration ratio of polysilazane increases as it approaches the surface of the coating layer 2.

[Example 1]
Based on the said embodiment, the coating molding of this invention was manufactured.
(1) Base Material A test piece having a length of 4 cm, a width of 2 cm, and a thickness of 3 mm was formed from a PBT (polybutylene terephthalate) resin used for tableware or the like.
(2) Coating liquid
(i) Coating liquid AQUAMICA (registered trademark) manufactured by AZ Electronic Materials Co., Ltd., based on NL110A-20 (containing 20 wt% polysilazane not including acrylic resin), containing 5 wt% polysilazane and containing acrylic resin An amount of 4 wt% was prepared.
(ii) Second coating liquid Based on a coating liquid (BR71 (trade name) manufactured by Mitsubishi Rayon) containing xylene as a solvent and not containing polysilazane, the acrylic resin content is 5 wt%, and the polysilazane content is 0. % Things were prepared.
(iii) Third coating solution Aquamica (registered trademark) manufactured by AZ Electronic Materials Co., Ltd., based on NL110A-20, a coating solution containing polysilazane without acrylic resin (polysilazane content 5 wt%, acrylic resin contained Amount 0%).
In this example, the coating liquid of (i) is “No 2”, the second coating liquid of (ii) is “No 1”, the third coating liquid of (iii) is “No 3”, and the mixing ratio of polysilazane and acrylic resin Is shown in the table below.

（３） 塗布
第二の実施形態と同様に、脱脂の前処理を施した基材の表面に、(ii)の第二コーティング液（Ｎｏ１）を塗布し、半乾き状態のときに、ポリシラザン及びアクリル系樹脂の双方を含む(i)のコーティング液（Ｎｏ２）を塗布する。最後に、コーティング液が半乾き状態のときに、(iii)の第三コーティング液（Ｎｏ３）を塗布した。
（４） 乾燥及び焼成
室温下で数時間放置して自然乾燥させ、コーティング層を完成させた。コーティング層の組成は、基材の表面近くではポリシラザンをほとんど含まず、コーティング層の表面近くではアクリル系樹脂をほとんど含まないものである。この後、基材をオーブンに入れ、１７０℃３０分で焼成し、常温で三週間放置してガラス転化した。
（５） 結果
当該試験片の上にカレーを載せ、室温、８０℃、１２０℃、１５０℃で３０分放置し、カレーを洗い落とした後に試験片の表面に汚れ（染み）が残存するか否かを調べた。
その結果を以下の表３に示す。なお、比較例は、本発明のコーティング層を形成しない同一材質の試験片である。

(3) Application As in the second embodiment, the second coating liquid (No. 1) of (ii) is applied to the surface of the base material that has been subjected to the degreasing pretreatment. The coating liquid (No. 2) of (i) containing both acrylic resins is applied. Finally, when the coating solution was semi-dry, the third coating solution (No. 3) of (iii) was applied.
(4) Drying and calcination The coating layer was completed by allowing it to stand for several hours at room temperature and let it air dry. The composition of the coating layer is such that it hardly contains polysilazane near the surface of the substrate, and hardly contains acrylic resin near the surface of the coating layer. Thereafter, the substrate was put in an oven, baked at 170 ° C. for 30 minutes, and allowed to stand at room temperature for 3 weeks to convert into glass.
(5) Result Whether or not dirt (stain) remains on the surface of the test piece after placing the curry on the test piece and leaving it at room temperature, 80 ° C., 120 ° C. and 150 ° C. for 30 minutes and washing off the curry. I investigated.
The results are shown in Table 3 below. In addition, a comparative example is a test piece of the same material which does not form the coating layer of this invention.

比較結果からわかるように、本発明のコーティング層を形成することで、１２０℃以下では、残存汚れの発生を効果的に防止することができた。

As can be seen from the comparison results, by forming the coating layer of the present invention, it was possible to effectively prevent the occurrence of residual dirt at 120 ° C. or lower.

[Example 2]
The applicant conducted a more detailed experiment based on the above-described embodiment, and examined a solution of a coating molded product in which no residual dirt was generated up to about 150 ° C.
(1) Acrylic resin BR-80 manufactured by Mitsubishi Rayon Co., Ltd. was dissolved in xylene to obtain a 10 wt% solution. Next, 10 wt% xylene solution of polysilazane (NL110A-10) manufactured by AZ Electronic Materials Co., Ltd. and 10 wt% xylene solution of BR-80 are mixed with a stirrer so that the following ratio is obtained, and coating is performed. Liquid.
[Solution 1] PHPS: BR80 = 5: 10 (wt%)
[Solution 2] PHPS: BR80 = 5: 8 (wt%)
[Solution 3] PHPS: BR80 = 5: 6 (wt%)
[Solution 4] PHPS: BR80 = 5: 4 (wt%)
[Solution 5] PHPS: BR80 = 5: 2 (wt%)
A white acrylic urethane resin coating (without polysilazane) was spray-coated on the surface, and an 80 × 40 × 3 mm PBT resin plate was prepared by heating and drying at 130 ° C. for 60 minutes. And using the said coating liquid, the dip coating was performed by the raising speed | rate of 1 mm / sec using the automatic raising apparatus. Thereafter, it was dried at room temperature for 10 minutes. Next, it baked at 170 degreeC for 1 hour, and obtained five types of 1st test pieces which formed the colorless and transparent ceramic / acrylic resin-type coating film for every said solution.
On each first test piece, a few drops of curry roux (“Golden Curry” (registered trademark) manufactured by Sakai Foods Co., Ltd.) were dripped and heated in an oven at 150 ° C. for 30 minutes. And the expression of the crack of the coating film was observed with a 100 times microscope.
The results are shown in Table 4 below.

(2) Next, a 10 wt% xylene solution of acrylic resin BR-80 manufactured by Mitsubishi Rayon Co., Ltd. and a 5 wt% xylene solution of polysilazane (NL110A-5) manufactured by AZ Electronic Materials Co., Ltd. have the following ratio. The mixture was mixed with a stirrer to obtain a coating solution.
[Solution 6] PHPS: BR80 = 5: 8 (wt%),
[Solution 7] PHPS: BR80 = 5: 5 (wt%)
[Solution 8] PHPS: BR80 = 5: 3.3 (wt%)
[Solution 9] PHPS: BR80 = 5: 2 (wt%)
[Solution 10] PHPS: BR80 = 5: 1.25 (wt%)
A first test piece having a coating film formed using the solution 3 of (1) was immersed in these coating solutions, and dip coating was performed at a lifting speed of 1 mm / sec using an automatic lifting device. Thereafter, it was dried at room temperature for 10 minutes. Next, baking was performed at 170 ° C. for 1 hour to obtain five types of second test pieces on which a colorless and transparent ceramic / acrylic resin-based coating film was formed.
The same Carreaux as before was dissolved in water and dropped on each of the second test pieces, and heated in an oven at 150 ° C. for 30 minutes, and the occurrence of cracks was observed with a 100-fold microscope.
The results are shown in Table 5.

(3) Next, a 10 wt% xylene solution of acrylic resin BR-80 manufactured by Mitsubishi Rayon Co., Ltd. and a 5 wt% xylene solution of polysilazane (NL110A-5) manufactured by AZ Electronic Materials Co., Ltd. have the following ratio. The mixture was mixed with a stirrer to obtain a coating solution.
[Solution 11] PHPS: BR80 = 5: 3.3 (wt%)
[Solution 12] PHPS: BR80 = 5: 2 (wt%)
[Solution 13] PHPS: BR80 = 5: 1.25 (wt%)
[Solution 14] PHPS: BR80 = 5: 0 (wt%)
A second test piece having a coating film formed using the solution 8 of (2) was immersed in these coating solutions, and dip coating was performed at a lifting speed of 1 mm / sec using an automatic lifting device. Thereafter, it was dried at room temperature for 10 minutes. Next, it baked at 170 degreeC for 1 hour, and obtained four types of 3rd test pieces which formed the colorless and transparent ceramic / acrylic resin-type coating film.
A solution prepared by dissolving the same Carreaux with water as described above was dropped on each of the third test pieces, oven-heated at 150 ° C. for 30 minutes, and the occurrence of cracks was observed with a 100-fold microscope.
The results are shown in Table 6.

From the above results, a suitable solution is selected from (1) to (3), and in order from the surface of the resin base material (PBT resin plate),
First layer: White acrylic urethane resin coating layer,
Second layer (lower layer part): [Solution 3] PHPS: BR80 = 5: 6 (wt%),
Third layer (middle layer part): [Solution 8] PHPS: BR80 = 5: 3.3 (wt%),
Fourth layer (upper layer portion): [Solution 12] PHPS: BR80 = 5: 2 (wt%)
A finished test piece (coating molding) having a coating layer was obtained. In the completed test piece thus obtained, the relative ratio of BR80 to PHPS gradually changes.
Using this completed test piece, the dye diffusion experiment of curry was repeated 30 times at 150 ° C. × 30 minutes, but no dye contamination could be confirmed. Thus, it turns out that the coating molding of this invention which changed the ratio of PHPS and PMMA gradually can prevent the contamination in a high temperature environment effectively.
In addition, about a lower layer part, any one or more in the solutions 1-3 in which the crack did not generate | occur | produce, and about the middle layer part, any one in the solutions 6-8 in which the crack did not generate | occur | produce or For a plurality (most preferably, solution 8) and the upper layer portion, solutions 11 and / or 12 in which generation of cracks and dye contamination were not recognized may be selected. At this time, the combination of the solutions in the lower layer portion, the middle layer portion, and the upper layer portion is selected so that the ratio of the acrylic resin to the polysilazane forms a gradient as shown in FIG. At this time, the optimum ratio of the acrylic resin and the polysilazane is determined by experiment according to the application and use environment of the coating molded product. Moreover, on the condition that cracks and dye contamination do not occur, a surface layer of only polysilazane that does not contain an acrylic resin may be formed on the upper layer portion.

Although a preferred embodiment of the present invention has been described, the present invention is not limited to the above-described embodiment.
For example, in the third embodiment described above, the following coating liquid is applied when the previously applied coating liquid is in a semi-dry state, but the next coating liquid is applied immediately after the coating liquid is applied. You may make it do.
Further, as the acrylic resin-containing coating liquid to be applied to the surface of the substrate, a coating liquid mainly composed of a UV curable acrylic resin may be used and cured by UV irradiation after application.
Furthermore, in the above-described embodiments and examples, the coating liquid (including the second and third coating liquids in the second embodiment) is described as being applied three times. However, a plurality of coating liquids having different mixing ratios are used. It goes without saying that the types may be prepared and applied four or more times.
In addition, the drying after all the coating liquids have been applied may be natural drying at room temperature, or may be forcibly dried in a drying furnace.

  The present invention is not limited to tableware, and can be widely applied to coating layer formation of materials for bathtubs, kitchens, sanitary products, automobiles, and the like, and coating moldings used therefor.

It is a conceptual diagram of the coating molding of this invention, The left side is a block diagram (part) of a base material and a coating layer, The right side is a graph which shows the change of the density | concentration ratio of acrylic resin and polysilazane.

Explanation of symbols

1 Base material 2 Coating layer

Claims (10)

In the method of forming a coating layer on the surface of a substrate,
A plurality of coating liquids containing polysilazane and acrylic resin are prepared by changing the mixing ratio of the polysilazane and acrylic resin,
In order from the coating liquid having a high mixing ratio of the acrylic resin, the coating layer was formed by coating the surface of the base material a plurality of times while replacing the plurality of types of coating liquids.
A method for forming a coating layer characterized by the above. A second coating solution containing the acrylic resin and not containing the polysilazane; and a third coating solution containing the polysilazane and not containing the acrylic resin;
2. The method according to claim 1, wherein after the second coating liquid is applied to the surface of the substrate, the coating liquid is applied once or a plurality of times, and finally the third coating liquid is applied again. Coating formation method. The method for forming a coating layer according to claim 1 or 2, wherein when the coating liquid or the second coating liquid previously applied is in a semi-dry state, the next coating liquid is applied again. In the process of apply | coating the said coating liquid, said 2nd coating liquid, or said 3rd coating liquid, at least 1 of each application | coating process has a baking process after application | coating. A method for forming the coating layer as described. In the method of forming a coating layer on the surface of a substrate,
(i) preparing an acrylic resin coating liquid not containing polysilazane and a polysilazane containing coating liquid not containing an acrylic resin;
(ii) applying the acrylic resin coating liquid to the surface of the substrate;
(iii) Immediately after applying the acrylic resin coating liquid or before the acrylic resin coating liquid is dried, the polysilazane-containing coating liquid is applied over the acrylic resin coating liquid,
(iv) Immediately after applying the polysilazane-containing coating solution or before the polysilazane-containing coating solution is dried, the concentration of the acrylic resin coating solution is reduced and applied over the polysilazane-containing coating solution,
(v) Immediately after applying the acrylic resin coating liquid or before the acrylic resin coating liquid is dried, the polysilazane-containing coating liquid is increased in concentration and applied over the acrylic resin coating liquid,
(Vi) Steps (iv) and (v) are repeated one or more times while increasing the concentration of the polysilazane-containing coating solution while decreasing the concentration of the acrylic resin coating solution toward the upper layer,
Finally, applying the polysilazane-containing coating solution,
A method for forming a coating layer characterized by the above. 6. The coating layer according to claim 5, wherein in the step of applying the polysilazane-containing coating solution after applying the acrylic resin coating solution, at least one of the application steps includes a baking step after application. Forming method. A coating layer having a ratio of polysilazane and acrylic resin in the range of 1.2 to 2.0 is prepared to form a lower layer portion of the coating layer, and in the range of 0.66 to 1.6 A thing is prepared and the middle layer part of a coating layer is formed, and the thing within the range of 0.4-0.66 is prepared, and the upper layer part of a coating layer is formed. The formation method of the coating layer in any one. A coating molded product in which a coating layer is formed on the surface of a substrate,
A coating molded article, wherein the mixing ratio of polysilazane and acrylic resin gradually changes from the surface of the substrate to the surface of the coating layer. The coating molding according to claim 8, wherein the coating layer does not contain polysilazane near the surface of the substrate and does not contain the acrylic resin near the surface of the coating layer. The ratio of acrylic resin to polysilazane in the coating solution is in the range of 1.2 to 2.0 in the lower layer portion of the coating layer, in the range of 0.66 to 1.6 in the middle layer portion, and 0.4 in the upper layer portion. The method for forming a coating layer according to claim 8 or 9, wherein the coating layer is in a range of ˜0.66.

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