JP2011122052A - Resin molded article, resin composition, and method for manufacturing resin molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce a resin molded article capable of achieving both scratch resistance with a scratch being hardly conspicuous in an automobile use environment and a brightness feeling compatible to a silver metallic color coating. <P>SOLUTION: The resin molded article is formed with an emboss depth of 5 to 20 μm of an embossed shape to be transferred onto the molded article using a resin composition prepared by adding an aluminum brightness material having a 20 μm or less particle size (average particle size) so that the concent of the bright material is 1.0 to 4.0 wt.% to a polypropylene composite resin material. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a resin molded product, a resin composition, and a method for producing the resin molded product, and more particularly to a technique for obtaining a metallic resin molded product by adding an aluminum glittering material or the like to a resin as a basic material.

  For example, in the automobile industry, users' needs for automobile interiors are diversified, and decorations such as metallic tone, wood grain tone, fabric tone and the like have been given mainly to interior resin parts. Among such resin decorative parts, there is a silver metallic-like resin decorative part with a lustrous feeling as one that is particularly demanding on the market.

  Conventionally, many of such silver metallic-tone resin decorative parts are often decorated by painting in order to achieve a sufficient glitter. However, the paint used in the painting process contains volatile organic compounds (hereinafter referred to as VOC (volatile organic compounds)) that may affect the environment as they are. There is a possibility of environmental deterioration.

  Therefore, in recent years, a painting process is omitted by molding a colored resin material in which a coloring material or a bright material is previously kneaded. Such non-painting of resin-decorated parts reduces the amount of paint used, reduces the emission or generation of VOCs, and further eliminates the need for energy saving and paint film removal by eliminating the painting process. It is very effective because it improves the recyclability of parts.

  On the other hand, in particular, a colored resin material kneaded with a glittering material has a problem that appearance defects such as a weld line are likely to occur when a resin decorative part is molded. As a technique for solving such a defect in appearance, conventionally, the shape of a mold or a resin molded product has been devised (for example, see Patent Document 1).

JP 2007-83434 A

  The applicant does not devise the shape of molds or resin molded products, and satisfies the mechanical properties, weather resistance (light) resistance, scratch resistance, etc. required for unpainted resin parts, while maintaining the silver metallic tone. An application for painting has already been filed (Japanese Patent Application No. 2008-281832). In this application, an aluminum brightening material developed mainly for styrenic copolymer resins typified by AES resin, ABS resin and ASA resin, and added to color the resin material in silver metallic color, its particle size and addition It was clarified that the amount affects the brightness and mechanical properties.

  On the other hand, polypropylene composite resin material (PP resin) is applied in large quantities in automotive interior and exterior parts such as bumpers, instrument panels and door trims because of its stable material performance and inexpensive material price. The most used. The use of PP resin for unpainted silver metallic resin parts also has significant advantages in terms of reducing material costs from styrene-based copolymer resins, reducing costs by integrating resin materials, and improving recycling efficiency. is there. In addition, since PP resin is superior in weather resistance (light) resistance and chemical resistance as compared with styrene-based copolymer, it has many advantages in durability under the severe long-term use environment of automobiles. However, PP resin is inferior to scratch resistance in terms of material hardness and surface characteristics compared to styrene copolymer, so it is applied to the high designability and appearance quality required for silver metallic resin parts. Has been considered difficult.

  As means for improving the scratch resistance of resin parts (hardly scratched or hardly noticeable), (a) increase the hardness of the resin material, (b) change the surface characteristics by adding a lubricant, etc. (c) For example, the molded product is given a grain shape. The means (a) and (b) affect the mechanical properties and various performances because the polymerization design and formulation of the resin material change. The means (c) is an effective means that does not change the material performance of the resin material, but depending on the embossed shape, the glitter of the molded product is significantly impaired.

  Therefore, the present invention aims to apply PP resin to non-coating of metallic resin parts. Specifically, for example, in order to prevent scratches that occur under the environment of use in automobiles and achieve a brilliant feel comparable to silver metallic paint, the grain size of the grain shape transferred to the molded product and the particle size of the aluminum glitter material to be added The purpose is to optimize the addition amount.

The resin molded product according to the present invention is characterized in that it is molded using a resin composition containing a glittering material with respect to a resin material obtained by adding an elastomer component to polypropylene.
In addition, the embossed shape having a texture depth of 5 μm or more and 20 μm or less is formed by transfer molding.
Further, the addition amount of the glittering material is 1.0 wt% or more and 4.0 wt% or less with respect to the resin material.
Further, the particle size of the glitter material is 20 μm or less.
Further, the embossing amount is 1.0% by weight with respect to the resin material, the grain size of the glittering material is set to 10 μm, and the embossed shape having a grain depth of 24 μm or less is transferred and molded. To do.
Further, the embossing amount is 1.0% by weight with respect to the resin material, the grain size of the glittering material is 20 μm, and the embossed shape is embossed with a grain depth of 28 μm or less. To do.
Further, the embossing amount is 0.5% by weight with respect to the resin material, the grain size of the glittering material is 10 μm, and the embossed shape is embossed with a grain depth of 5 μm or less. To do.
Further, the glitter material is an aluminum glitter material.
Further, it is characterized in that it is molded into an automotive interior / exterior resin part.

The resin composition according to the present invention is characterized in that a glittering material is contained in a resin material obtained by adding an elastomer component to polypropylene.
The method for producing a resin molded product according to the present invention is characterized by molding using a resin composition containing a glittering material with respect to a resin material obtained by adding an elastomer component to polypropylene.

According to the present invention, it is possible to mold a resin molded product having a high glitter feeling without painting.
Specifically, for example, it is possible to mold a resin molded product that achieves both scratch resistance that makes scratches less noticeable in an automobile use environment and a glittering feeling comparable to a silver metallic coating.

It is a figure for demonstrating the addition amount of a brilliant material, the particle diameter of a brilliant material, and the grain depth in the resin composition which concerns on this embodiment. It is a figure which shows the embossed shape in the resin molded product which concerns on this embodiment. It is a figure for demonstrating the measurement principle of the angle-change colorimetry measuring method. It is a figure which shows the relationship between the grain depth and FF value in the sample from which the particle diameter of a luster material differs. It is a figure which shows the relationship between the embossing depth and FF value in the sample from which the addition amount of a luster material differs. It is a figure which shows the testing machine used for the scratch resistance test method. It is a figure which shows the scratching needle used for a scratch resistance test method. It is a figure which shows the scratch | wound generated on a sample in the scratch resistance test method. It is a figure which shows the relationship between the embossing depth and the glossiness difference in the sample with the particle diameter of 10 micrometers of glittering material, and the addition amount of 1.0 wt%. It is a figure which shows the relationship between the grain depth and the glossiness difference in the sample from which the particle diameter of a luster material differs. It is a figure which shows the relationship between the embossing depth and the glossiness difference in the sample from which the addition amount of a luster material differs.

Embodiments of the present invention will be described below.
The present invention provides a resin composition in which an aluminum glittering material having a particle size (average particle size) of 20 μm or less is added to a polypropylene composite resin material so as to be 1.0 to 4.0 wt% (wt%). The resin-molded product is molded by changing the depth of the embossed shape to be transferred (transfer molding) from 5 μm to 20 μm. That is, the resin molded product is molded with the particle diameter of the glitter material, the addition amount of the glitter material, and the embossing depth as in the range A shown in FIG.

  By molding under such conditions, it is possible to produce a silver metallic resin part that is compatible with the expression of brightness comparable to that of silver metallic coating and the prevention of scratches that occur, for example, in an automobile use environment. Moreover, it can be applied not only to the silver metallic color but also to other metallic colors such as gold and gun metallic. The above-mentioned conditions have been found as a result of sharp research in consideration of various requirements relating to scratch resistance, glitter and physical properties, and the details thereof will be described later.

<About resin materials as basic materials>
In the present embodiment, a polypropylene composite resin material (PP composite resin material) that is translucent in a state before coloring is used as the resin material. First, the base polypropylene was a homopolypropylene having excellent transparency among polypropylenes.
Polypropylene: Homopolypropylene (flexural modulus 2300 MPa, Charpy impact strength (23 ° C.) 2.0 kJ / m ² )
However, homopolypropylene is inferior in impact resistance compared to block polypropylene. Conventionally, a rubber component is added to improve impact resistance, but strength, rigidity, and heat resistance are lowered. As a countermeasure, a filler is added, but the transparency of the resin material is lowered, or a weld line is generated in the resin molded product.

Therefore, in this embodiment, an elastomer component is added. Here, an elastomer component such as an olefin-based elastomer can improve impact resistance, but has a problem that transparency and rigidity are lowered. Therefore, in this embodiment, styrene-ethylene-butadiene-styrene, which is a styrene-based elastomer, is added instead of the olefin-based elastomer.
Elastomer: Styrene / ethylene / butadiene / styrene (SEBS) (weight average molecular weight 60,000, styrene content 30 wt%)
By adding SEBS, as compared with the case of adding a filler or an olefin-based elastomer, the transparency and rigidity of the PP composite resin material are reduced and impact resistance can be improved.

  In addition, the addition amount of SEBS is 20 to 28% by weight, desirably 22 to 23% by weight. The PP composite resin material blended in this way was able to maintain a total light transmittance of 70% or more (test piece thickness of 2 mm). The total light transmittance was evaluated as an index of transparency. In measuring the total light transmittance, a haze computer HZ-2 manufactured by Suga Test Instruments Co., Ltd. was used.

<About glitter materials>
In the present embodiment, an aluminum glittering material (aluminum paste: manufactured by Toyo Aluminum Co., Ltd.) was used as a glittering material contained in the PP composite resin material as a basic material in order to develop a metallic tone. When the particle size (average particle size) of the aluminum glitter material is 40 μm or more, the glitter feeling is lowered and it is difficult to suppress metamerism. Therefore, the maximum particle diameter of the aluminum glittering material is set to 40 μm. In addition, when the amount of the aluminum glittering material exceeds 5 wt%, the material properties are remarkably lowered and compounding becomes difficult. Therefore, the maximum amount of addition is set to 4 wt%.

<About the resin composition>
By melting and kneading the above-described aluminum glittering material into the above-described PP composite resin material, a silver-metallic polypropylene-based resin composition can be produced. The melt-kneading can be carried out and granulated using a kneader such as a single screw extruder, a twin screw extruder, a Banbury mixer, a roll mixer, a kneader or the like. In the present embodiment, typically, a silver metallic-like resin molded product is molded, and in this case, coloring is unnecessary. On the other hand, when molding a resin molded product of gold metallic tone or so-called gun metallic tone, coloring is performed by appropriately mixing an inorganic pigment and an organic pigment in a molten state.
In this embodiment, as shown in Tables 1 and 2 below, experimental samples were produced in which the particle size and the addition amount of the aluminum glittering material were changed.

<About wrinkle shape>
FIG. 2 shows a schematic view of the embossed shape transferred to the resin molded product. In the present embodiment, an embossed plate producing mold for injection molding is used, in which the embossed pitch is the constant height (500 μm to 800 μm) and the embossed depth is 5 μm to 51 μm. . A textured plate having a thickness of 3 mm was produced by injection molding. Further, a so-called mirror-finished flat plate mold having a mold finish of # 3000 or more was also used, and a grain having a grain depth of 0 μm was fabricated by injection molding.
Using the polypropylene resin composition in which the particle size and the addition amount of the aluminum glittering material were changed as described above, a texture plate (resin molded product) having a different texture depth was molded.
In this embodiment, the influence which the depth of the embossing of the resin molded product has on the glitter and scratch resistance was verified.

<Illumination evaluation>
In this embodiment, a flip-flop value (hereinafter referred to as FF value), which is an index indicating glitter feeling, is calculated by the following formula (1), and the glitter feeling is evaluated.
FF value = lightness at highlight (25 °) / lightness at shade (75 °) (1)

  Each angle of 25 ° and 75 ° indicates an angle when the measurement sample (resin molded product) is placed on a plane and the vertical direction is set as a reference (0 °). Basically, the metallic tone has a finished surface with a strong specular reflection component. Therefore, the specular reflection component with respect to the light source in the highlight direction (25 °) is strong, and the diffuse reflection component is weak in the shade direction (75 °). Therefore, the brightness is expressed by the FF value that is the ratio of the brightness during the highlight and shade. Can be evaluated. In this evaluation, the higher the FF value, the higher the glitter feeling. The FF value is sensitively influenced by the particle size (specific surface area) and the amount added (total area) of the glittering material.

As a method of measuring the brightness of the reflection component for obtaining the FF value, a so-called variable angle colorimetry measurement method is used. The brightness at the highlight (25 °) and the brightness at the shade (75 °) in Equation (1). )
FIG. 3 is a diagram for explaining the measurement principle of the angle-change colorimetric measurement method. As shown in FIG. 3, in the angle-change colorimetric measurement method, three light sources (1 to 3) having different arrangement angles are arranged, and the brightness of the reflection component of the measurement sample with respect to the light source is arranged in the vertical direction of the measurement sample. This is done by measuring with the received light sensor. In FIG. 3, the arrangement angles of the light sources 1 to 3 are 25 °, 45 °, and 75 °, respectively, with respect to the vertical direction of the measurement sample. A spectrocolorimeter (CM-512m3) manufactured by Konica Minolta Co., Ltd. was used as a measuring instrument for performing the measurement.

  FIG. 4 and Table 3 show the results of the FF values measured by changing the grain depth for the experimental samples in Table 1 in which the particle diameter of the aluminum glittering material is changed. Note that a molded article with a silver metallic coating as an example of comparison generally requires an FF value of 2.0 or more for automobile interior use.

From FIG. 4 and Table 3, it was found that the following tendency was observed when the aluminum glittering material was added in a constant amount of 1.0 wt% and the particle diameter and grain depth of the aluminum glittering material were changed. did.
(1-1) The FF value was higher as the particle diameter of the aluminum glitter material was smaller in the region where the depth of the grain was shallow, and the glitter feeling was higher.
(1-2) When the particle size was 40 μm (sample D), the FF value was 2 or less regardless of the depth of the embossing, and the same level of brightness as the silver metallic coating could not be achieved.
(1-3) A sample having a high glitter feeling in a region where the depth of the grain was shallow (that is, a sample having a smaller particle diameter) showed a greater degree of reduction in the glitter feeling as the grain depth was increased.
(1-4) When the particle size was 5 μm (sample A), the depth of the embossing was 24 μm or more and the FF value was 2 or less.

  From the above, it can be seen that in order to achieve an FF value of 2 or more, which is the same level of glittering feeling as that of the silver metallic paint, the particle diameter of the aluminum glittering material should be regulated to 20 μm or less and the grain depth to 20 μm or less. . Note that the grain depth of 20 μm or less is a result of calculating a linear approximation expression from a plot of each point of the sample A and deriving a condition for an FF value of 2.0 or more.

  FIG. 5 and Table 4 show the results of the FF values measured by changing the embossing depth for the experimental samples in Table 2 in which the addition amount of the aluminum glittering material is changed.

From FIG. 5 and Table 4, it was found that when the particle size of the aluminum glittering material was fixed to 10 μm and the addition amount of the aluminum glittering material and the depth of the embossing were changed, the following tendency was observed.
(2-1) The FF value showed a higher value as the addition amount of the aluminum glittering material was larger in the region where the depth of the grain was shallow, and the glitter feeling was higher.
(2-2) When the addition amount was 0.5 wt% (sample E), the FF value was 2 or less when the depth of the embossing was 13 μm or more, and the same level of brightness as the silver metallic coating could not be achieved.
(2-3) A sample having a high glitter feeling in a region where the depth of the embossing is shallow (that is, a sample with a larger amount of addition) has a greater degree of reduction in the glitter feeling as the embossing depth becomes deeper.
(2-4) When the addition amount was 2.0 wt% (Sample F) and 4.0 wt% (Sample G), the grain depth was 24 μm or more and the FF value was 2 or less.

  5 and Table 4, it can be seen that in order to achieve the FF value of 2 or more, it is only necessary to define the addition amount of the aluminum luminous material to 1 wt% or more to 4 wt% or less and the grain depth to 20 μm or less. Note that the upper limit of the amount added was specified to be 4 wt% in consideration of a significant decrease in material properties and difficulty in compounding.

From the result of the glitter feeling evaluation as described above, it is desirable that the particle diameter, the addition amount, and the depth of the embossing material of the aluminum glitter material are within the ranges specified below.
(3-1) The particle diameter of the aluminum glitter material is 20 μm or less.
(3-2) The addition amount of the aluminum luminous material is 1 wt% or more and 4 wt% or less.
(3-3) The depth of the texture is 20 μm or less.

<Scratch resistance evaluation>
In the present embodiment, scratch resistance, which is highly likely to occur under the usage environment of automobile interior / exterior resin parts, was taken up, and scratch resistance was evaluated.
FIG. 6 is a diagram showing a testing machine used in the scratch resistance test method. In this embodiment, as a testing machine, an automatic crosscut testing machine No. 551-AUTO was used. The testing machine 10 includes a sample stage 11 on which the sample W is placed, a scratching needle 12 that causes scratches on the sample W, a mounting jig 13 that attaches the scratching needle 12 to the testing machine 10, and a scratching needle 12 with a constant load. A weight 14 for pressing against W is provided.

FIG. 7 is a view for explaining the shape of the scratching needle 12. The scratching needle 12 is made of sapphire, the tip of a needle having a diameter of 3 mm is formed at an angle of 60 °, and chamfering of R 0.3 mm is performed.
FIG. 8 is a diagram for explaining scratches generated on the sample by the testing machine 10. The scratches 20 are generated in a grid pattern with 11 × 11 scratches in the vertical and horizontal directions with a grid interval t = 1 mm.

  Numerical evaluation and visual evaluation were performed on the scratches generated on the sample by the testing machine 10. In numerical evaluation, as shown in FIG. 3, the incident angle of the light source was 45 ° (light source 2), and the measurement angle was similarly 45 °. The gloss value before and after the test was measured, and the difference in gloss was evaluated. For the measurement of the gloss value, a digital variable gloss meter manufactured by Suga Test Instruments Co., Ltd. was used. The smaller the gloss difference, the better the scratch resistance, and the scratches are less noticeable.

FIG. 9 shows the results of numerical evaluation of scratch resistance in an experimental sample (sample B) having an aluminum glittering material particle size of 10 μm and an addition amount of 1.0 wt% by the difference in gloss before and after the test.
From FIG. 9, it was found that as the depth of the texture increases, the difference in gloss decreases and the scratch resistance is excellent. Further, from the visual evaluation, it was found that the scratches were not noticeable when the depth of the embossing was 5 μm or more.

  Next, with respect to the experimental samples in Tables 1 and 2 in which the particle size and the addition amount of the aluminum glittering material are changed in Tables 5 and 6, respectively, the gloss difference was measured by changing the embossing depth and the visual evaluation results. It shows. The numerical value indicates the gloss difference before and after the scratch resistance test, and the parenthesis indicates visual evaluation. ○ indicates that the scratch is not easily noticeable, and x indicates that the scratch is easily noticeable.

10 and 11 show the numerical evaluation results of the scratch resistance in the range of the grain depth of 5 to 28 μm.
It was found that the following tendencies were observed when the depth of the aluminum glitter material and the grain was changed.
(4-1) As the depth of the texture increases, the gloss difference decreases and the scratch resistance is excellent.
(4-2) When the depth of the texture was 5 μm or more, the gloss difference was 5 or less, and the scratches were not noticeable.
(4-3) The silver metallic colored resin material changed the conspicuousness of scratches with a gloss difference of about 5 as a boundary.
(4-4) No effect on the scratch resistance was observed due to the difference in the particle size or addition amount of the aluminum glittering material.

  From the above, when scratch-free scratches, which are particularly noticeable in the environment of use in automobiles, are to be made unpainted with a silver metallic polypropylene-based resin composition, regardless of the particle size or amount of aluminum glittering material. In other words, it has been found that the depth of the texture transferred to the molded product is 5 μm or more, which is effective.

  As described above, by optimizing the embossing depth of the embossed shape transferred to the molded product and the particle size and amount of the aluminum glittering material to be added, scratches that occur in the environment of use in automobiles can be prevented and comparable to silver metallic paint It is possible to mold an unpainted silver metallic resin part with a polypropylene-based resin composition that achieves both radiance.

As mentioned above, although this invention was demonstrated with various embodiment, this invention is not limited only to these embodiment, A change etc. are possible within the scope of the present invention.
For example, in the non-painting of resin parts, it can be expected to be applied to parts that require the same glitter feeling as metallic paint. For example, not only automobile interior / exterior parts but also motorcycle parts, home appliances, AV equipment, OA equipment, cosmetics, daily necessities and office supplies are expected to be widely developed. Further, for example, it is possible to deal with various metallic colors without being limited to the silver metallic color.

  10: Testing machine 11: Sample stage 12: Scratching needle 13: Mounting jig 14: Weight

Claims (11)

  A resin molded product formed by using a resin composition containing a glittering material for a resin material obtained by adding an elastomer component to polypropylene.   2. The resin molded product according to claim 1, wherein a textured shape having a textured depth of 5 μm or more and 20 μm or less is formed by transfer molding.   The resin molded product according to claim 2, wherein the amount of the glittering material added is 1.0 wt% or more and 4.0 wt% or less with respect to the resin material.   The resin molded product according to claim 2 or 3, wherein a particle diameter of the glitter material is 20 µm or less. The amount of the glittering material added to the resin material is 1.0% by weight,
The particle size of the glitter material is 10 μm,
2. The resin molded product according to claim 1, wherein a textured shape having a textured depth of 24 [mu] m or less is transferred and molded. The amount of the glittering material added to the resin material is 1.0% by weight,
The particle size of the glitter material is 20 μm,
2. The resin molded product according to claim 1, wherein a textured shape having a textured depth of 28 μm or less is transferred and molded. The amount of the glittering material added to the resin material is 0.5% by weight,
The particle size of the glitter material is 10 μm,
2. The resin molded product according to claim 1, wherein a textured shape having a textured depth of 5 [mu] m or less is transferred and molded.   The resin molded product according to any one of claims 1 to 7, wherein the glitter material is an aluminum glitter material.   The resin molded product according to any one of claims 1 to 8, wherein the resin molded product is molded into an interior / exterior resin part for an automobile.   A resin composition characterized in that a glittering material is contained in a resin material obtained by adding an elastomer component to polypropylene.   A method for producing a resin molded product, comprising molding a resin composition containing a glittering material to a resin material obtained by adding an elastomer component to polypropylene.

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