JP5843262B2 - Resin composition for coating - Google Patents

Description

The present invention relates to a resin composition for coating dishes such as dishes, teacups, and trays.

Melamine-based resin molding materials are excellent in heat resistance, solvent resistance, and wear resistance, and are therefore used in dishes such as dishes, teacups, and trays. Tableware is required to have design properties such as color, pattern, and mat.

A method of improving design properties by coating a tableware using a melamine-based resin molding material with a resin composition to change surface characteristics is known as a glaze method. For example, in Patent Document 1, for the purpose of improving the design of tableware, a melamine resin and a coating pigment obtained by coating the surface of mica particles and / or alumina particles with titanium oxide and / or iron oxide are blended. A molded coating composition is disclosed.

In addition, tableware using melamine-based resin molding material is designed to transfer the texture on the surface of the tableware using a mold that has been subjected to texture processing when molding tableware using melamine-based resin molding material. A method of performing a matting process for improvement and prevention of slipping is known. For example, Patent Document 2 discloses a mixture of a pulverized powder of a used melamine resin molded product that does not contain a pulverized powder of a recycled melamine resin molded product as a main component and a melamine resin material that does not contain a recycled melamine resin material, , A tableware that has been subjected to a matte finish on the entire surface after molding and further glazed.

However, the design of the tableware described in Patent Document 2 has room for improvement. When making tableware using melamine resin molding material, the surface of the mold during molding is textured and the texture is transferred to the surface of the tableware. As the number of mold shots increases, the mold wears out. As a result, transfer defects occur and the design of the tableware is inferior. Furthermore, it is difficult to clean a mold whose surface is processed with fine irregularities. If a mold that is not sufficiently cleaned and remains dirty on the surface is used for molding, the appearance of the molded tableware becomes poor. Therefore, it has been difficult to stably obtain the designability of tableware by the method of transferring the texture on the surface of the tableware.

Furthermore, the tableware using the glaze to which the light scattering agent containing the melamine resin is added has the same refractive index of the glaze and the light scattering agent, and the design is inferior because the light is not scattered. On the other hand, although the tableware which added the light-scattering agent containing a silica etc. to a glaze will scatter light, since a glaze will become cloudy by addition of a light-scattering agent, the external appearance of tableware will become bad. Furthermore, if the adhesion between the glaze and the light scattering agent is poor, the appearance of the tableware that has been repeatedly used for cleaning becomes poor.

JP 2007-182524 A JP 2010-195871 A

The subject of this invention is providing the resin composition for coating | cover which does not generate | occur | produce the appearance defect even if it uses repeatedly washing | cleaning use of tableware, and can improve the designability of tableware easily.

In order to solve the above problems, the coating resin composition of the present invention includes a melamine resin composition and a spherical body having a melamine resin layer (A) and a silica layer (B) in this order from the inner layer. Features.

Moreover, another form of the coating resin composition of the present invention is characterized in that the spherical body is 5 to 30 parts by mass with respect to 100 parts by mass of the melamine resin composition.

In another embodiment of the coating resin composition of the present invention, the spherical body has a diameter of 6 to 15 μm.

Another form of the coating resin composition of the present invention is such that the spherical body has a melamine-based resin layer (A), a silica layer (B), and a melamine-based resin layer (C) in order from the inner layer. It is characterized by being.

Another embodiment of the present invention is tableware using the coating resin composition described above.

By coating the tableware with the coating resin composition of the present invention, the design of the tableware can be easily improved. In addition, the tableware coated with the coating resin composition of the present invention does not cause poor appearance even when repeatedly used.

Hereinafter, the coating resin composition of the present invention and tableware using the coating resin composition will be described in detail.

The coating resin composition of the present invention includes a melamine-based resin composition. Since the coating resin composition of the present invention and the tableware using the melamine-based resin molding material have good adhesion, the tableware coated with the coating resin composition of the present invention has poor appearance even when repeatedly used. Does not occur. The coating resin composition of the present invention is particularly used for coating molding on tableware using a melamine-based resin molding material.

In the present invention, the melamine-based resin composition is a melamine / formaldehyde resin obtained by reacting melamine and formaldehyde. The melamine-based resin composition is prepared by reacting melamine and formaldehyde in an aqueous solution in a molar ratio of 1: 1.5 to 1: 4.5, preferably 1: 2 to 1: 3. Manufacturing. At that time, the reaction is completed in about 10 to 100 minutes by reacting at a melamine concentration of 20 to 60%, a reaction temperature of 40 to 100 ° C., and weakly acidic to weakly alkaline. The obtained initial condensate aqueous solution is made into a solid powdery melamine resin by spray drying or the like.

Examples of guanamines to be blended in the melamine resin include benzoguanamine, acetoguanamine, formguanamine, phenylacetoguanamine, and CTU guanamine. Among them, benzoguanamine is preferable for the coating resin composition of the present invention because of characteristics such as water resistance and gloss. The compounding quantity of the guanamine to the melamine resin of the said melamine-type resin composition is 5-100 mass parts of guanamines with respect to 100 mass parts of melamine resins. If the blending amount of guanamines is less than 5 parts by mass, the stain resistance and flexibility will be unfavorable, and if it exceeds 100 parts by mass, the surface hardness and fluidity will decrease and the moldability will be unfavorable. .

The spherical body contained in the coating resin composition of the present invention is a spherical body having a melamine resin layer (A) and a silica layer (B) in order from the inner layer. Since the coating resin composition has such a configuration, even if the melamine-based resin composition and the spherical body are mixed, appearance defects such as the cloudiness of the coating resin composition do not occur. preferable. In addition, the coating resin composition has good adhesion to the melamine resin composition and the spherical body, and even when the tableware coated with the coating resin composition of the present invention is repeatedly washed and used, This is preferable because no defect occurs. Furthermore, since the coating resin composition has a small difference in specific gravity between the melamine resin composition and the spherical body, the melamine resin composition and the spherical body when coated on tableware. Are preferable because they are not separated, become substantially uniform, and have a good appearance.

The spherical body has a core-shell structure. The refractive index (nD) of the melamine-based resin layer (A) as the core is about 1.65, and the refractive index (nD) of the silica layer (B) as the shell is about 1.46. Since the spherical body has a refractive index difference between the core and the shell, the visible light is reflected by both the outermost layer of the spherical body and the core-shell interface, thereby coating the coating resin composition of the present invention. Tableware has a feature that the designability can be easily improved.

The spherical body can be produced, for example, according to a method described in JP-A-2005-171033. Specifically, the spherical body is obtained by charging melamine, 37% formalin, aqueous silica sol, sodium sulfate and water in predetermined amounts, reacting them with conditions, and then drying and grinding.

The coating resin composition of the present invention preferably contains 5 to 30 parts by mass, and preferably 15 to 20 parts by mass of the spherical body with respect to 100 parts by mass of the melamine resin composition. When the spherical body is contained in an amount of 5 parts by mass or more, the tableware coated with the coating resin composition of the present invention can improve the design properties better. Further, when the spherical body is contained in an amount of 30 parts by mass or less, the tableware coated with the coating resin composition of the present invention can further improve the adhesion between the coating resin composition and the coated tableware. it can. Furthermore, the tableware which coat | covered the resin composition for a coating | coated of this invention does not reflect light too much, and is excellent in the frosting effect.

The spherical body has a diameter of 6 to 15 μm, preferably 9 to 12 μm. The diameter of the spherical body is obtained by directly measuring the diameters of a total of 150 spherical bodies in five different visual fields in a state where 30 spherical bodies are included in one visual field in an electron microscope (SEM), and obtaining an average value thereof. Can be determined. Since the diameter of the spherical body is 6 μm or more, the design properties of the tableware coated with the coating resin composition of the present invention are improved more satisfactorily. In addition, since the diameter of the spherical body is 15 μm or less, the tableware coated with the coating resin composition of the present invention further improves the adhesion between the coating resin composition and the tableware to be coated. Can do. Furthermore, the tableware which coat | covered the resin composition for a coating | coated of this invention does not reflect light too much, and is excellent in the frosting effect.

The spherical body preferably has a small dispersion. The diameter of the spherical body is preferably 10% or less as a coefficient of variation obtained by dividing the standard deviation by the average particle diameter.

The spherical body is substantially spherical. “Substantially spherical” means that, for example, a nearly spherical shape can be confirmed visually by SEM. The tableware coated with the coating resin composition of the present invention is preferable because the coating resin composition contains a substantially spherical light scattering agent, so that the appearance effect that the matte effect changes depending on the position of the coated tableware to be observed does not occur. . For example, tableware in which a coating resin composition containing an irregular light scattering agent is coated and molded has a problem that the matte effect changes depending on the viewing position.

Furthermore, the spherical body is preferably a spherical body having a melamine-based resin layer (A), a silica layer (B), and a melamine-based resin layer (C) in order from the inner layer. If the outermost layer of the spherical body is a melamine-based resin layer (C), the adhesion between the melamine-based resin composition and the spherical body can be further improved, and thus the coating is coated with the coating resin composition of the present invention. Tableware does not cause poor appearance even after repeated cleaning. The compositions of the spherical melamine resin layer (A) and melamine resin layer (C) may be the same or different from each other.

As the spherical body having the melamine-based resin layer (A), the silica layer (B), and the melamine-based resin layer (C) in order from the inner layer, for example, product name Opt Beads manufactured by Nissan Chemical Industries, Ltd. is commercially available.

Tableware using the coating resin composition of the present invention exhibits an excellent matting effect despite the small unevenness of the coating surface. For example, tableware in which the surface of a mold at the time of molding is textured and the texture is transferred to the surface has a design property, but there is a problem that stains tend to remain on the surface of the tableware because the surface has irregularities. In addition, the textured tableware has a problem that the unevenness of the surface disappears due to repeated washing and use, and the matting effect is reduced. The tableware using the coating resin composition of the present invention has small surface irregularities, so that no stains remain and a permanent matte effect is obtained. Furthermore, the tableware using the coating resin composition of the present invention can easily have a matte effect without using a dedicated mold.

The coating resin composition of the present invention includes, for example, a curing catalyst such as benzoic acid, phthalic anhydride, p-toluenesulfonic acid, zinc stearate, myristin, in addition to the melamine resin composition and the spherical body. Lubricants such as zinc acid, various dyes and pigments, and other additives can be contained.

The coating resin composition of the present invention can be prepared by any means capable of uniformly mixing a melamine resin composition, a spherical body and other additives, such as a kneader, ribbon blender, Henschel mixer, ball mill, roll kneading, It can be produced using a mixer such as a machine or a tumbler.

Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to these examples.

(Production Example 1)
Melamine (Mitsubishi Chemical Corporation: oil melamine) 3000 g, formalin 3431.2 g, and water 880.3 g are put into a flask with a reflux condenser, and heated and reacted at 90 ° C. with stirring to a cloudiness point of 60 ° C. When it became, 0.3g NaOH was introduce | transduced and it cooled and the melamine resin initial condensate was obtained. The powdery melamine resin used in the present invention was obtained by drying the obtained melamine resin initial condensate at about 200 ° C. with a spray dryer.

(Example 1)
The melamine-based resin composition was 350 parts by weight of the powdered melamine resin obtained in Production Example 1, 150 parts by weight of benzoguanamine powder, 9 parts by weight of benzoic acid, 2.5 parts by weight of zinc stearate, and 0.5 parts by weight of polyethylene glycol. The parts were obtained by pulverizing with a ball mill for 8 hours and mixing the contents sufficiently uniformly. The coating resin composition is a spheroid having a melamine resin layer (A), a silica layer (B), and a melamine resin layer (C) in order from the inner layer to the melamine resin composition, manufactured by Nissan Chemical Industries, Ltd. 90.4 parts by mass of the trade name “Optobead 10500M” was added, and the ball mill was further operated for 30 minutes. The coated tableware was obtained by using the obtained coating resin composition and a test piece prepared under the following conditions. The obtained tableware was evaluated by the method shown separately.

(Examples 2 to 5)
The resin composition for coating of each example and the tableware that was formed by coating were obtained by the same procedure as in Example 1 except that the composition shown in Table 1 was used. Furthermore, the tableware of each Example was evaluated similarly to Example 1.

(Comparative Example 1)
The coating resin composition and the coated tableware of Comparative Example 1 were obtained by the same procedure as in Example 1 except that the spherical body was not included. Furthermore, the tableware of Comparative Example 1 was evaluated in the same manner as in Example 1.

(Comparative Example 2)
The resin composition for coating and the cooked tableware of Comparative Example 2 were prepared by using a colorless and transparent regenerated melamine resin which was crushed into an irregular shape having a size of approximately 10 to 20 μm instead of a spherical body. It was obtained by the same procedure as in 1. The regenerated melamine resin pulverized product used at this time had an aspect ratio of 1.7, and it was confirmed by a microscope that the shape was irregular. Furthermore, the tableware of Comparative Example 2 was evaluated in the same manner as in Example 1.

(Comparative Example 3)
The table-top tableware of Comparative Example 3 was prepared by applying a coating resin composition used in Comparative Example 1 on the surface of a test piece obtained by applying a texture to the surface of the mold during molding and transferring the texture on the surface. It was obtained by doing. Furthermore, the tableware of Comparative Example 3 was evaluated in the same manner as in Example 1.

(Preparation of test piece)
The test piece used for coating molding was produced under the following conditions.
Molding machine: 45-ton press Mold: Soup bowl Molding material for the base: Nicarbide MC
HE3180
Mold temperature (upper / lower): 170 ° C / 170 ° C
Molding pressure and time: 8.3 MPa × 120 seconds

(Coating molding conditions)
Tableware was produced by molding a coating resin composition to be evaluated on the specimen under the following conditions after molding the specimen under the above conditions.
Molding machine: 45-ton press Mold: Soup bowl Mold temperature (upper mold / lower mold): 170 ° C / 170 ° C
Molding pressure and time: 9.8 MPa × 60 seconds

The coating resin compositions and tableware in each of the examples and comparative examples were evaluated by the methods shown below.

(Frosting effect and design)
The matte effect was evaluated by determining the glossiness by the following method. The glossiness was measured using a gloss meter VG-2000 manufactured by Nippon Denshoku Industries Co., Ltd. at an incident angle of 20 °, a light receiving angle of 20 °, and an incident angle of 60 ° and a light receiving angle of 60 °. The average value was used. For the evaluation of the matte effect, the glossiness is preferably 65 or less under the conditions of an incident angle of 20 ° and a light receiving angle of 20 °. In addition, the evaluation of the design property is “excellent” when the matte effect is clearly recognized by visual inspection, “less” when the matte effect is smaller than “excellent” but “good” when the matte effect is smaller, and the matte effect is not visible. Were determined to be “poor”.

(Repeated cleaning test)
The evaluation of the repeatability was performed by visually judging the appearance after the accelerated evaluation of the repeatability of tableware. The evaluation was performed by boiling the tableware in boiling water for 1 hour and then drying at 80 ° C. for 1 hour as one cycle, and the presence or absence of cracks on the surface of the tableware after 10 cycles of testing or peeling of the coating resin composition. It was done by checking. Repeated cleaning performance is evaluated as “excellent” if the appearance is good, “possible” if the appearance is inferior to “excellent”, but “possible” if the appearance is poor due to cracking or peeling. And judged respectively.

(Evaluation)
As shown in Table 1, the tableware using the coating resin composition produced in Example 1 has a glossiness of 26 under the conditions of an incident angle of 20 ° and a light receiving angle of 20 °, and from any direction. It was excellent in the designability which can visually confirm the frosting effect. In addition, the evaluation results of repeated cleaning properties were excellent, with no cracks or peeling off of the coating resin composition on the tableware surface after 10 cycles of the test. Moreover, the evaluation results of the tableware produced in Examples 2 to 5 were as shown in Table 1.

Tableware using the coating resin composition prepared in Comparative Example 1 has a glossiness of 87 under the conditions of an incident angle of 20 ° and a light receiving angle of 20 °, and the matte effect from any direction cannot be visually confirmed. It was inferior in nature. In addition, the evaluation results of repeated cleaning properties were excellent, with no cracks or peeling off of the coating resin composition on the tableware surface after 10 cycles of the test.

The tableware using the coating resin composition prepared in Comparative Example 2 has a glossiness of 83 under the conditions of an incident angle of 20 ° and a light receiving angle of 20 °, and when visually confirmed, the matte effect from any direction. However, it was inferior to the designability. Moreover, the tableware using the coating resin composition produced in Comparative Example 2 had irregularities on the surface. Furthermore, the evaluation results of repeated cleaning properties were inferior because it was possible to confirm the absence of the regenerated melamine pulverized product in the coating resin composition on the tableware surface after 10 cycles of the test.

Tableware using the coating resin composition prepared in Comparative Example 3 had a glossiness of 17 under the conditions of an incident angle of 20 ° and a light receiving angle of 20 °. The design of the tableware using the coating resin composition prepared in Comparative Example 3 was visually confirmed, although the glossiness was small, the matte effect was small and inferior to Example 1. Moreover, it confirmed that the surface had an unevenness | corrugation. Furthermore, the evaluation results of repeated cleaning properties were inferior after 10 cycles of testing, because the coating resin composition on the tableware surface had cracks.

As mentioned above, it turned out that the designability of tableware can be easily improved by using the coating resin composition of this invention. Furthermore, it has been found that tableware using the coating resin composition of the present invention exhibits excellent characteristics that do not cause poor appearance even after repeated washing and use.

The coating resin composition of this invention can improve the designability of tableware easily by coat | covering on the surface of the tableware using a melamine type resin molding material.

Claims (4)

A coating resin composition comprising: a melamine resin composition; and a spheroid having a melamine resin layer (A) , a silica layer (B), and a melamine resin layer (C) in order from the inner layer. The coating resin composition according to claim 1, wherein the spherical body is 5 to 30 parts by mass with respect to 100 parts by mass of the melamine-based resin composition. The resin composition for coating according to claim 1, wherein the spherical body has a diameter of 6 to 15 μm. Tableware using the coating resin composition according to any one of claims 1 to 3 .