JP2003064188A - Resin molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily provide an inexpensive resin molded product having higher impact strength than conventional ones. SOLUTION: This resin molded product is made of a thermoplastic resin such as a propylene-based resin and has the following characteristics: the aspect ratio for the particle size of the rubber component present in the region corresponding to a thickness of 20 μm from the external surface is >=1.37, the external surface roughness Ra is <=0.125 μm, and the external surface represents the reverse side when viewed from the direction of applying impact on this resin molded product.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a resin molded article having excellent impact strength.

[0002]

2. Description of the Related Art Conventionally, a resin molded article made of a thermoplastic resin has been widely used for interior and exterior parts of automobiles, motorcycle parts, home appliances and the like. One of them is impact performance. To increase the impact strength, absorb the impact by devising the method of reinforcing the material surface (for example, adding a filler such as rubber or talc for a resin molded product made of polypropylene) and the structure of the resin molded product. There are known methods for improving impact strength.

[0003]

However, there is no limit to the demand for such performance improvement, and it is desirable that the impact strength can be further improved at a simpler and lower cost. An object of the present invention is to provide a resin molded product which is simple and low in cost, and has excellent impact strength.

[0004]

The present invention relates to a resin molded product which is made of a thermoplastic resin and has an aspect ratio of the particle diameter of the rubber component existing at a thickness of 20 μm from the outer surface of 1.37 or more. Is. Hereinafter, the present invention will be described in detail.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The thermoplastic resin used in the present invention is
It is not particularly limited, for example, ethylene, propylene, butene-1, pentene-1, hexene-1, 3-
Α-, such as methylbutene-1, 4-methylpentene-1
Olefin homopolymers, copolymers with other unsaturated monomers that can be copolymerized with these, or α with 3 or more carbon atoms
-Copolymers and the like composed of at least two kinds of monomers selected from olefin and ethylene.
Moreover, you may use these individually or in 2 or more types. Among the above, high density polyethylene, medium density polyethylene,
Ethylene resins such as low density polyethylene, linear low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer; isotactic polypropylene, syndiotactic polypropylene,
An olefin resin such as a propylene resin such as a propylene-ethylene block copolymer or a random copolymer is preferable. Among these, propylene-based resin is particularly preferable.

The resin molded product of the present invention is made of such a thermoplastic resin and contains the rubber component in a state in which it is not molecularly compatible. When using a thermoplastic resin originally containing such a rubber component like a propylene-ethylene block copolymer, such a thermoplastic resin may be used as it is as the thermoplastic resin of the present invention. ,
A thermoplastic resin composition comprising such a thermoplastic resin and a thermoplastic elastomer is also suitably used. Also,
When the thermoplastic resin containing no rubber component is used, another material that can be used as the thermoplastic resin containing the rubber component is also used. When a thermoplastic resin containing no rubber component is used, a thermoplastic resin composition comprising the thermoplastic resin and a thermoplastic elastomer is preferably used.

Examples of the thermoplastic elastomer include olefin elastomers and styrene elastomers, and one kind may be used alone, or two or more kinds may be used in combination. Examples of the olefin elastomer include ethylene-propylene copolymer rubber and ethylene-propylene-
Non-conjugated diene copolymer rubber, ethylene-butene-1 copolymer rubber, ethylene-butene-1-non-conjugated diene copolymer rubber, propylene-butadiene copolymer rubber,
An amorphous random copolymer elastic body containing an olefin as a main component, such as an ethylene-octene copolymer rubber, may be mentioned. Examples of the non-conjugated diene include dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylnorbornene, ethylidenenorbornene and the like. Examples of the styrene elastomer include styrene-butadiene block copolymer, styrene-isoprene block copolymer, hydrogenated styrene-isoprene block copolymer, styrene-grafted ethylene-propylene copolymer rubber, styrene-acrylonitrile-grafted ethylene-propylene. Copolymer rubber, styrene-grafted ethylene-propylene-non-conjugated diene copolymer rubber, styrene-ethylene-butylene-styrene block copolymer rubber and the like can be mentioned.

In the resin molded product of the present invention, the rubber components are not molecularly compatible with each other and form particles when observed with an electron microscope. The resin molded product of the present invention is a resin molded product excellent in impact strength, in which the aspect ratio of the particle diameter of the rubber component present in the thickness of 20 μm from the outer surface is larger than a certain level. In the resin molded product of the present invention, the aspect ratio has an average value of 1.37 or more, preferably 1.5 to 9.5, and more preferably 1.7 to 9.
It is 3.

If the outer surface of the resin molded product of the present invention is smooth, the impact strength is more excellent. The surface roughness Ra of the outer surface of the resin molded product of the present invention is preferably 0.125.
It is less than or equal to μm, and more preferably less than or equal to 0.108 μm.

In the present invention, the specific outer surface of the resin molded article described above may be all the outer surfaces of the resin molded article, but the direction in which impact is applied to the resin molded article. It is preferable that the outer surface on the back surface side as viewed from above is the above-described specific outer surface.

The thermoplastic resin used in the present invention may contain an inorganic filler as long as the object of the present invention is not impaired. Examples of the inorganic filler include talc, mica, wollastonite, calcium carbonate, barium sulfate, magnesium carbonate, clay, alumina, silica, calcium sulfate, carbon fiber, glass fiber, metal fiber, titanium oxide, carbon black, magnesium hydroxide. , Diatomaceous earth, etc. These may be used alone or in combination of two or more.

Further, the thermoplastic resin used in the present invention includes
Additives such as an antioxidant, an ultraviolet absorber, a lubricant, a pigment, an antistatic agent, a copper damage inhibitor, a neutralizing agent and a nucleating agent can be contained within the range not impairing the object of the present invention.

The resin molded product referred to in the present invention refers to a molded product obtained by molding the above thermoplastic resin by a generally known molding method.
Typical known molding methods include, for example, injection molding, gas-assisted injection molding, sandwich injection molding, injection compression molding, injection press molding, and other compression molding, blow molding, injection blow molding, sheet molding, heat molding. Molding (vacuum molding and pressure molding) and film extrusion molding are also included.

In order to obtain the resin molded product of the present invention by the injection molding method, it is advisable to carry out the molding under the condition that a large shear is applied. For example, it is molded by at least one of the following molding conditions.・ Lower the mold temperature.・ Cylinder-Lower the temperature.・ Increase the injection speed.・ Use highly viscous materials. Decrease the plate thickness, etc.

The resin molded product of the present invention can also be obtained by subjecting the outer surface of the molded product obtained by a usual molding method to flame treatment. The type of flame and the method of flame treatment referred to herein may be any, for example, a method of flame treating the outer surface of the resin molded product for a predetermined time using a gas torch filled with an LPG combustible gas. Can be mentioned. In the flame treatment, the flame treatment time is usually carried out within a range in which the resin molded product is not deformed, preferably 1 to 60 seconds, more preferably 2
~ 55 seconds. Furthermore, it is desirable that the surface temperature of the resin molded product during the flame treatment is 600 ° C. or higher.
00 ° C. is more preferable.

[0016]

EXAMPLES The present invention will be described below based on Examples and Comparative Examples, but the present invention is not limited to these Examples and Comparative Examples.

<Observation method of outermost surface of resin molded product> KEYEN
The average roughness state (Ra) of the surface of the resin molded product was observed with a surface shape observation microscope manufactured by CE.

(Morphology observation method near the surface of the resin molded product> The particle size of the rubber component existing near the surface of the resin molded product (20 μm from the outermost layer) is observed by a transmission electron microscope (TEM), and their aspect The ratio was calculated.

<Impact resistance evaluation method> A test piece from the center of the resin molded product was cut out, and the impact strength of the test piece was determined to be BS13.
It measured based on 30. Specifically, the obtained resin molded product was cut into 10 mm (MD direction) × 5 mm (TD direction) to obtain a test piece. Next, on the chuck for exclusive use of the shock measurement device (Dynestat tester: manufactured by Tester Sangyo),
Adjust so that the hammer hits the position of 1.75 times the thickness of the test piece (that is, the position of 5.25 mm for a test piece with a thickness of 3 mm) (specified in BS1330),
I put it on. Next, hang the hammer on the hook of the lifting device at the angle specified for each hammer used, align the main body pointer with the angle position of the lifted hammer, remove the hammer from the hook, and remove the hammer from the test piece described above. Hit the hitting point of and read the angle of the hammer that was swung up BS133
The energy of the test piece was calculated by a calculation formula based on the rule of 0.

[Comparative Example 1] Propylene-ethylene block copolymer (Sumitomo Chemical Co., Ltd., Sumitomo Noblene A)
W564, MFR: 30 g / 10 minutes, yield strength: 278
kgf / cm ² , content of ethylene-propylene random copolymer part = 14% by weight, content of repeating unit derived from ethylene of ethylene-propylene random copolymer part = 37% by weight), injection molding machine (Sumitomo Heavy Industries) Machinery Co., Ltd.
Made by Neomat 515/150), molding temperature 220
A flat plate of 120 × 120 × 3 mmt was molded at 0 ° C. The average surface roughness (Ra) of the outermost surface of the resin molded product is 0.12.
5 μm, and the aspect ratio of the rubber particle diameter existing from the outer surface of the resin molded product to 20 μm is 1.0 to 1.36.
Met. Table 1 shows the impact strength of this flat plate.

[Examples 1 to 3] A gas torch (Prince gas torch manufactured by Nippon Gas Co., Ltd.) filled with an LPG combustible gas on the outer surface of a resin molded article obtained in the same manner as in Comparative Example 1 Flame treatment was performed with a flame at a surface temperature of the molded product of 650 ° C. Table 1 shows the results obtained by measuring the treatment time, the surface roughness of the flame-treated surface, the aspect ratio of the particle diameter of the rubber component present in the thickness of 20 μm from the outer surface, and the impact strength of each of Examples 1 to 3.

[0022]

[Table 1]

[0023]

As described above in detail, according to the present invention, there is provided a resin molded product which is simple, low in cost and excellent in impact strength.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4F071 AA02 AA10 AA14 AA15 AA16                       AA17 AA18 AA19 AA20 AA21                       AB03 AB06 AB18 AB21 AB24                       AB26 AB28 AB30 AF23 AG30                       AH07 AH11 BA01 BB03 BB05                       BB06 BC07 BC10 BC16                 4F073 AA06 AA21 BA04 BA06 BA07                       BA08 BA09 BA10 BA11 BB02                       BB09 GA03                 4J002 AA01W AC00X BB01W BB03W                       BB05W BB06W BB07W BB11X                       BB12W BB14W BB14X BB15W                       BB15X BN03X BP01X BP02X                       FD010 GN00

Claims (4)

[Claims] 1. A thermoplastic resin, 20 μm from the outer surface
A resin molded product in which the aspect ratio of the particle diameter of the rubber component present in the thickness up to m is 1.37 or more. 2. The surface roughness Ra of the outer surface is 0.125 μm.
The resin molded product according to claim 1, which is as follows. 3. The outer surface is the back surface side when viewed from the direction in which an impact is applied to the resin molded product.
The resin molded product described. 4. The resin molded product according to claim 1, wherein the thermoplastic resin is a propylene resin.