Resin molded member

Abstract

To provide a resin molded member having excellent surface scratch resistance and glossy texture.SOLUTION: A resin molded member containing a crystalline resin and further containing an inorganic filler, characterized by a surface gloss of 35 to 75 Gs (20°), has excellent surface scratch resistance and a glossy texture, such as a texture similar to that of ceramics, and can be used in combination with ceramics to create an unified design for toilet lids and containers / covers for associated equipment.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a resin molded member having excellent scratch resistance and a glossy texture.

Background Art

[0002] Various molded members are formed of resin materials. In addition to the surface being less likely to be scratched, in members where the appearance is emphasized, a texture such as gloss is required. Further, when the molded member is used in combination with other members, for example, pottery, it is desirable that their appearances are similar, which can provide a unified design for the product and increase the product value.

[0003] Urea resin is often cited as a resin that has scratch resistance and excellent gloss, but it may be inferior to other types of resins in terms of dimensional stability, moldability, and material cost. On the other hand, resins that are advantageous in terms of price and moldability (for example, polypropylene-based resins) may be inferior in scratch resistance. For such resins, in order to improve scratch resistance, it has been proposed to mix inorganic fillers such as glass fibers to increase mechanical strength (Japanese Unexamined Patent Application Publication No. 2005-188182 (Patent Document 1)), or to increase hardness by making the resin crystalline (Japanese Unexamined Patent Application Publication No. 2021-137567 (Patent Document 2)).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The inventors have now found that in a resin molded member, by mixing an inorganic filler into a crystalline resin, a resin molded member excellent in surface scratch resistance and having a glossy texture can be obtained. The present invention is based on such findings.

[0006] Therefore, an object of the present invention is to provide a resin molded member excellent in surface scratch resistance and having a glossy texture.

Means for Solving the Problems

[0007] The resin molded member according to the present invention is a resin molded member comprising a crystalline resin and further comprising an inorganic filler. And the gloss of its surface is characterized in that Gs(20°) is 35 to 75.

Effects of the Invention

[0008] According to the present invention, a resin molded member excellent in surface scratch resistance and having a glossy texture is provided. The resin molded member according to the present invention has scratch resistance not inferior to that of urea resin, and further has a glossy appearance, and is advantageous in that it can be realized by a relatively inexpensive resin. Furthermore, its gloss can be made similar to the appearance of pottery, and by combining it with a product made of pottery, for example, by combining it with a toilet bowl and its lid, an integrated design can be obtained, and the advantage of increasing the product value can also be obtained.

Modes for Carrying Out the Invention

[0009] Definition Surface gloss: Gs(20°) and Gs(60°) In this specification, the surface glosses Gs(20°) and Gs(60°) mean 20-degree specular gloss and 60-degree specular gloss in a measurement method conforming to JIS Z8741: Specular Glossiness - Measurement Method. That is, in the same measurement method, it means the gloss Gs(20°) at an incident angle of 20 degrees and Gs(60°) at an incident angle of 60 degrees.

[0010] DOI value by wave scan DOI measuring device As used in this specification, the DOI value measured by the wave scan DOI measuring device specifically refers to the DOI value measured by the Wave-Scan DIO (orange peel measuring device) manufactured by BYK Gardner (Germany). This device optically measures the light / dark pattern of wavelengths on the target surface in a manner similar to the human eye. In this microwave scan, a laser point light source irradiates laser light at an angle of 60° inclined from the perpendicular to the sample surface, and the detector measures the reflected light at the same angle opposite to the perpendicular. By moving the laser point light source over the painted sample surface for scanning, the light / dark of the reflected light is measured one by one at determined intervals, and the optical profile of the sample surface can be detected. The detected optical profile is spectrally analyzed through a frequency filter to analyze the substrate, internal, and surface structures in painting and the like. The characteristic spectrum of this device is as follows. du: Wavelength of 0.1 mm or less Wa: Wavelength of 0.1 - 0.3 mm Wb: Wavelength of 0.3 - 1 mm Wc: Wavelength of 1 - 3 mm Wd: Wavelength of 3 - 10 mm We: Wavelength of 10 - 30 mm Sw: Wavelength of 0.3 - 1.2 mm Lw: Wavelength of 1.2 - 12 mm DOI: Wavelength of 0.3 mm or less Here, DOI is a parameter composed of du, Wa, and Wb DOI = f(du, Wa, Wb) and is represented as such. In the present invention, the above DOI value is used.

[0011] Resin molded member The resin molded member according to the present invention is a resin molded member containing a crystalline resin, and further contains an inorganic filler. And it is characterized in that the gloss of its surface is 35 to 75 at Gs(20°). According to a preferred embodiment of the present invention, the gloss Gs(20°) of the surface of the resin molded member is 40 to 65. According to another preferred embodiment, the gloss of the surface of the resin molded member is 70 to 89 at Gs(60°), more preferably 75 to 89. The resin molded member according to the present invention has excellent surface scratch resistance and a glossy texture because Gs(20°), and further Gs(60°), is within the above range.

[0012] Also, according to a preferred embodiment of the present invention, the DOI value of the surface of the resin molded member measured by a wave scan DOI measuring device is preferably 50 to 76, more preferably 58 to 68.

[0013] The inorganic filler contained in the resin molded member according to the present invention is preferably glass fiber or mica (plate-like mineral). It is well known that the incorporation of an inorganic filler into a resin molded member is for enhancing its strength. However, in the present invention, unexpectedly, the effect of enhancing the gloss texture of the surface of the resin molded member is obtained by such incorporation. The texture can be made similar to that of pottery, and it is preferable because it can bring an integrated design and increase the product value when combined with a product made of pottery, for example, combined as a toilet bowl and its lid.

[0014] In the present invention, the content of the inorganic filler may be appropriately determined within the range where the above scratch resistance and glossy texture are obtained. According to a preferred embodiment of the present invention, it is preferably in the range of 5 to 35% by mass, more preferably in the range of 10 to 30% by mass. When the content of the inorganic filler is within these ranges, good scratch resistance and a glossy texture can be obtained. Especially regarding the gloss, by setting the inorganic filler within the above range, an excessive gloss is not imparted, and a resin molded member with excellent texture can be obtained.

[0015] In the present invention, the size and shape of the inorganic filler may be appropriately determined within the range in which the above-described scratch resistance and glossy texture can be obtained. According to a preferred embodiment of the present invention, the shape is fibrous, the diameter is about 6 μm to 24 μm, and the length is about 10 μm to 3000 μm.

[0016] According to a preferred embodiment of the present invention, the crystalline resin contained in the resin molded member has a crystallinity of 50% or more in its outermost layer, and it is preferable that the crystallinity of this outermost layer is maintained from the outermost layer, that is, the outermost surface of the member, to a depth of at least 9.0 μm.

[0017] In the above aspect, the crystallinity of the resin refers to the ratio of the crystalline portion in the crystalline resin, and the measurement method thereof is well-known. For example, as the measurement method of crystallinity, a density method, a thermal analysis method, an NMR method, an IR method, etc. can be mentioned. In the present invention, preferably, the crystallinity is measured by an X-ray diffraction method. That is, the resin molded member is irradiated with X-rays, and from the obtained diffraction information, the scattering region derived from the crystal and the scattering region derived from the non-crystal are separated, and it is calculated as the ratio of the crystal scattering intensity to the total scattering intensity, and this is taken as the crystallinity.

[0018] In the present invention, "the crystallinity of the outermost layer is maintained" means that in addition to the crystallinity value being the same from the outermost surface of the member to a depth of at least 9.0 μm, up to a depth of at least 9.0 μm, compared with the crystallinity of the outermost layer, the change is + in the range of about 7%, preferably + within the range of 5%.

[0019] By maintaining the above-described predetermined crystallinity from the outermost surface of the member to a depth of at least 9.0 μm, the surface of the member has the property of being difficult to be scratched by rubbing, and further has various properties required for the resin molded member, that is, excellent strength, durability, and small dimensional change after molding. The present invention is advantageous in that a good resin member can be realized also in properties generally considered to deteriorate when the resin crystallizes.

[0020] According to a preferred embodiment of the present invention, the crystallinity of the outermost layer is 50% or more, more preferably 70% or more. Further, such crystallinity of the outermost layer is retained to at least a depth of 9.0 μm, more preferably to at least a depth of 50 μm.

[0021] Examples of the crystalline resin that can be used as the molded member according to the present invention include polypropylene (PP), polybutylene terephthalate (PBT), polyethylene (PE), polyamide (PA), polyacetal, polyoxymethylene (POM), polyethylene terephthalate (PET), polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), etc. In the present invention, urea resin is not classified as a crystalline resin and is excluded.

[0022] The molded member according to the present invention is preferably used as a water-related member. In the present invention, the water-related member means a member that is splashed with water and wiped, and / or a member that is frequently cleaned using water and has water wiped off. Since the molded member according to the present invention is excellent in scratch resistance on its surface, the generation of scratches on the surface due to the operation of wiping off water on the surface of the member can be suppressed. As a result, it can be used for a long period without impairing the designability of the surface of the molded member.

[0023] Specific examples of the molded member according to the present invention include a toilet seat; a lid of a toilet; a case cover of a warm water washing toilet seat; a resin member of a remote control; a side panel of a toilet; a resin member of a paper holder; resin members around a bathroom counter, a bath apron, a washstand, and a washbasin; resin members such as handles and small item containers in a kitchen storage section; a resin member of a hand dryer, etc.

[0024] According to one preferred embodiment of the present invention, the resin molded member is a toilet lid. The toilet lid has a lid upper surface portion that is exposed upward and a lid lower surface portion that is exposed downward in its closed state, and scratch resistance is required on both surfaces. Therefore, in this toilet lid, the outermost layer of the member preferably means both the above-mentioned upper surface portion and the lower surface portion, and it is preferable that both surfaces satisfy the conditions of the present invention. Further, as described above, the texture of the resin molded member according to the present invention can be made similar to the texture of pottery, and by making it the toilet lid combined with pottery or the container / cover of its accessory equipment, an integrated design can be achieved.

[0025] Manufacturing method The molded member according to the present invention is manufactured by a method capable of controlling the crystallization of the crystalline resin, and is preferably manufactured by the following method. That is, the resin mixed with the inorganic filler heated to the melting temperature is filled into a mold heated to a temperature in the range of the crystallization temperature of the resin + of the resin by 10 ° C., held in the mold for at least 20 seconds or more, and after cooling the mold, a resin molded member can be preferably obtained by this method. Here, the crystallization temperature of the resin can be derived by the following method, for example, by differential scanning calorimetry (DSC measurement). The crystalline resin is heated to a temperature above the melting point, and after the resin is completely melted, the resin is cooled at a cooling rate of, for example, about 5 ° C. / min. When the temperature is lowered, an exothermic peak associated with crystallization is observed, and the temperature of that peak is taken as the crystallization temperature.

[0026] According to one embodiment of the present invention, when the resin is a PP resin, the mold is heated to a temperature of 110 ° C. or higher and 130 ° C. or lower, and the resin heated to a temperature higher than the temperature of the mold is filled into the mold. Here, according to a preferred embodiment of the present invention, the temperature of the resin is 180 ° C. to 220 ° C. or higher, more preferably about 190 ° C. After filling the resin into the mold, if necessary, the temperature of the mold is heated, and the mold temperature is maintained in the range of 110 ° C. or higher and 130 ° C. or lower for at least 20 seconds or more, preferably 40 seconds or more, and more preferably 60 seconds or less, and then the molded member is obtained after heat dissipation or cooling.

Example

[0027] The present invention will be further described by the following examples, but the present invention is not limited to these examples.

[0028] Resin material used As the polypropylene (PP) resin used in the following examples and comparative examples, a PP resin with an MFR (temperature 230°C, load 2.16 kgf) of 19 g / 10 min in accordance with JIS K-7210 was prepared, and resin pellets 1 to 3 mixed with the following amounts of glass fiber were produced. Resin pellet 1 (containing 10% by mass of glass fiber (GF)) To the prepared PP resin, glass fiber (GF) was added so as to be 10% by mass, and melt-kneading was performed using an extruder to produce resin pellet 1. Resin pellet 2 (containing 20% by mass of glass fiber (GF)) To the prepared PP resin, glass fiber (GF) was added so as to be 20% by mass, and melt-kneading was performed using an extruder to produce resin pellet 2. Resin pellet 3 (containing 30% by mass of glass fiber (GF)) To the prepared PP resin, glass fiber (GF) was added so as to be 30% by mass, and melt-kneading was performed using an extruder to produce resin pellet 3. Reference example resin pellet Without adding glass fiber to the prepared PP resin, melt-kneading was performed using an extruder to produce a reference example resin pellet.

[0029] Examples 1 to 3 Using resin pellets 1 to 3, the toilet lid was manufactured by injection molding under the following conditions. That is, the resin pellet was heated to 190°C and filled into a mold heated to 120°C. Then, the temperature of the mold was maintained at 120°C for 40 seconds, and after cooling, the toilet lid was taken out of the mold.

[0030] Comparative examples 1 to 3 The toilet lid was manufactured under the following conditions by injection molding using resin pellets 1 to 3. That is, the resin pellets were heated to 190 °C, filled into a mold heated to 40 °C, and then the heating of the mold was stopped. After 20 seconds, the toilet lid was taken out of the mold.

[0031] Reference example 1 Using reference resin pellets, a toilet lid was manufactured under the same conditions as in Examples 1 to 3.

[0032] Reference example 2 A toilet lid (manufactured by TOTO Ltd.) obtained by press molding urea resin was prepared.

[0033] Measurement of crystallinity The crystallinity of the toilet lid of the reference example was measured with the following measuring apparatus and conditions. Analyzer: SmartLab manufactured by Rigaku Corporation X-ray source: CuKα (45 kV - 200 mA) Optical system: Out-of-plane (incident angle: 0.3, 1, 2, 3, 5°) Stage: RxRy attachment head Detector: HyPix-3000 Scan mode: 0 dimension Scan speed: 3.5 °·min-1 Step width: 0.056 ° Scan axis: 2θ Scan range: 5 to 40 ° Incident slit box: 0.072 mm Longitudinal limiting slit: 10 mm Light receiving slit box 1: 1.0 mm Light receiving slit box 2: 1.1 mm

[0034] The X-ray incident angle (ω) was changed from 0.3 to 5 degrees. This X-ray incident angle (ω) corresponds to an analysis depth (X-ray penetration depth) of 2.4 μm to 46.0 μm.

[0035] The crystal area and the amorphous area were determined from the X-ray diffraction patterns obtained at each X-ray incident angle, and the crystallinity was calculated using the following arithmetic expression. Crystallinity (%) = [(Area of crystal part) / (Area of crystal part + Area of amorphous part)] × 100

[0036] The depth from the measured surface and the crystallinity were as shown in Table 1 below.

Table 1

[0037] Evaluation of scratch resistance: Pencil hardness The pencil hardness tests of the lids obtained in Examples 1 to 3 and Comparative Examples 1 to 3, as well as the lids of Reference Examples 1 and 2, were conducted in accordance with JIS K 5600-5-4:1999. For pencil hardness less than 6B not specified in JIS K 5600-5-4:1999, the Hi-uni series manufactured by Mitsubishi Pencil Co., Ltd. was used. The results were as shown in Table 2 below.

[0038] Evaluation of surface gloss The DOI values of the lids obtained in Examples 1 to 3 and Comparative Examples 1 to 3, as well as Reference Examples 1 and 2, were measured using a Wave-ScanDIO (orange peel measuring device) manufactured by BYK Gardner (Germany). The results were as shown in Table 2 below. However, for Comparative Examples 1 to 3, they were below the measurement lower limit value (30).

[0039] Elastic modulus Strip-shaped test pieces were molded in accordance with JIS K7152 under the same conditions as in Examples 1 to 3, Comparative Examples 1 to 3, and Reference Example 1. Also, strip-shaped test pieces of Reference Example 2 were prepared. For these strip-shaped test pieces, in accordance with S K7171, the flexural modulus of the test pieces was evaluated at room temperature. The results were as shown in Table 2 below.

[0040]

Table 2

[0041] Preferred embodiment of the present invention Preferred embodiments of the present invention are as follows. (1) A resin molding member comprising a crystalline resin, further comprising an inorganic filler, and having a gloss of 35 to 75 at Gs(20°) on its surface. (2) The resin molding member according to (1) above, wherein the crystallinity in the outermost layer is 50% or more, and the crystallinity of the outermost layer is maintained up to a depth of at least 9.0 μm from the outermost layer. (3) The resin molding member according to (1) or (2) above, having a gloss of 40 to 65 at Gs(20°) on its surface. (4) The resin molding member according to any one of (1) to (3) above, having a gloss of 70 to 89 at Gs(60°) on its surface. (5) The resin molding member according to any one of (1) to (4) above, having a gloss of 75 to 89 at Gs(60°) on its surface. (6) The resin molding member according to (1) or (2) above, having a DOI value of 50 to 76 measured by a wave scan DOI measuring device on its surface. (7) The resin molding member according to any one of (1) to (6) above, having a DOI value of 58 to 68. (8) The resin molding member according to any one of (1) to (7) above, having an inorganic filler content of 5 to 35% by mass. (9) The resin molding member according to any one of (1) to (8) above, wherein the inorganic filler is glass fiber or mica. (10) The resin molding member according to any one of (1) to (9) above, wherein the crystalline resin is at least one selected from the group consisting of polypropylene (PP), polybutylene terephthalate (PBT), polyethylene (PE), polyamide (PA), polyacetal, polyoxymethylene (POM), polyethylene terephthalate (PET), polyetheretherketone (PEEK), polyphenylene sulfide (PPS), and polytetrafluoroethylene (PTFE). (11) A resin molded member which is a lid and is any one of (1) to (10) described above.

Claims

1. A resin molded member comprising a crystalline resin, further comprising an inorganic filler, and having a gloss on its surface of 35 to 75 at Gs(20°).

2. The resin molded member according to claim 1, wherein the crystallinity in the outermost layer is 50% or more, and the crystallinity of the outermost layer is maintained to a depth of at least 9.0 μm from the outermost layer.

3. The resin molded member according to claim 1 or 2, having a gloss on its surface of 40 to 65 at Gs(20°).

4. The resin molded member according to claim 1 or 2, having a gloss on its surface of 70 to 89 at Gs(60°).

5. The resin molded member according to claim 1 or 2, having a gloss on its surface of 75 to 89 at Gs(60°).

6. The resin molded member according to claim 1 or 2, having a DOI value measured by a wave scan DOI measuring device on its surface of 50 to 76.

7. The resin molded member according to claim 1 or 2, having a DOI value of 58 to 68.

8. The resin molded member according to claim 1 or 2, wherein the content of the inorganic filler is 5 to 35% by mass.

9. The resin molded member according to claim 1 or 2, wherein the inorganic filler is glass fiber or mica.

10. The resin molded member according to claim 1 or 2, wherein the crystalline resin is at least one selected from the group consisting of polypropylene (PP), polybutylene terephthalate (PBT), polyethylene (PE), polyamide (PA), polyacetal, polyoxymethylene (POM), polyethylene terephthalate (PET), polyether ether ketone (PEEK), polyphenylene sulfide (PPS), and polytetrafluoroethylene (PTFE).

11. The resin molded member according to claim 1 or 2, which is a toilet lid.

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