JP3842926B2 - Polyolefin-based resin sheet and resin-coated metal plate - Google Patents

Description

【００４８】
表１から明らかなように、マトリックスを構成する結晶性ポリプロピレン系樹脂として結晶融解ピーク温度が１３０℃未満にも明瞭に存在するような原料を用いたり（比較例１）、改質剤として従来から使用されているポリオレフィン系熱可塑性エラストマーであるＴＰＯを用いた場合（比較例２）には、特に低温加工時における難白化性を発現させることができないことが判る。
【００４９】
また、改質剤として分子鎖中に結晶性のブロックと非晶性のブロック部分が混在している立体規則性を制御された軟質ポリプロピレン系樹脂を用いても、立体規則性や添加量が規定の範囲内に入っていない場合には、それぞれ折り曲げ加工性や打ち抜き加工性、表面硬度の面で問題がある（比較例３〜５）。
さらに改質剤としてのＴＰＳの多量の添加は二次加工特性は良好になるものの耐擦傷性の面で問題がある（比較例６）。
【００５０】
一方、実施例１〜２のように、結晶融解ピーク温度が１３０℃以上にのみ存在する結晶性ポリプロピレン系樹脂と改質剤として特定の立体規則性を有する軟質ポリプロピレン系樹脂及びＴＰＳを用い、それぞれ規定量の範囲で配合したものについては、折り曲げ加工性、難白化性、打ち抜き加工性、表面硬度のバランスに優れていることが判る。
【００５１】
【発明の効果】
本発明によれば、樹脂被覆金属板としての折り曲げ加工性や打ち抜き加工性等の二次加工性と難白化性、耐擦傷性などのバランスに優れたポリオレフィン系樹脂被覆金属板を提供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polyolefin-based resin sheet and a resin-coated metal plate that can be suitably used as members of building materials, home appliances, furniture, and the like.
[0002]
[Prior art]
Conventionally, as a resin-coated metal plate, for example, various resin-coated metal plates used for building materials such as interior and exterior, home appliances, and furniture are most commonly coated with a vinyl chloride resin sheet in terms of processing characteristics, cost, etc. Has been used. However, the vinyl chloride resin has a problem that hydrogen chloride gas is generated at the time of combustion, and the incinerator is easily damaged when it is disposed of by disposal such as incineration. Therefore, in recent years, there is a demand for a resin-coated metal plate that does not use such a vinyl chloride resin sheet.
[0003]
Under such circumstances, various studies have been made on metal plates coated with a polyolefin resin sheet that are relatively inexpensive and have relatively few problems due to gas generated during combustion.
However, the polyolefin-based resin-coated metal plate that is currently used industrially, when performing secondary processing such as bending under low temperature conditions such as cold districts, cracks and cracks occur in the coated resin sheet, There was a problem that the processed part was whitened. In addition, polyolefin resin-coated metal plates that are less prone to cracking and cracking in resin sheets coated under such conditions have been studied. However, even if the above problems can be solved, the resin sheet is galling when punched. In addition, there is a problem that a whisker-like resin piece remains on the end face of the resin sheet after punching, and there is a problem that the surface of the resin sheet is easily damaged in practical use.
[0004]
As described above, all of secondary workability such as bending workability and punching workability under low temperature conditions, whitening resistance that is difficult to whiten, and scratch resistance that is difficult to damage the sheet surface. None of them met the required characteristics.
[0005]
[Means for Solving the Problems]
The object of the present invention is to eliminate the above-mentioned problems by using a polyolefin resin sheet having appropriate flexibility, impact resistance, surface hardness, etc. as a resin sheet for coating, and to bend the resin coated steel sheet. Secondary workability such as workability and punching workability, whitening resistance, scratch resistanceHigh-speed impact adhesion bending workability under low temperature conditionsAn object of the present invention is to provide a well-balanced polyolefin resin sheet and resin-coated metal plate.
[0006]
[Means for Solving the Problems]
This invention discovered the polyolefin-type resin sheet and resin-coated metal plate which eliminated the said trouble, and the place made into the summary is (a) component which comprises the following matrix, and ( b) Componentas well as(C) It consists of a mixture of components, and the ratio of each component is (a) / {(b) + (c)} = 75 to 90/25 to 10 and (c) ≦ 15 by weight ratio. And a resin-coated metal plate coated with the sheet.
[0007]
Component (a): a crystalline polypropylene resin having a crystal melting peak temperature of only 130 ° C. or higher
(B) component;¹³Stereoregularity in which the sum of the mesopentad fraction and the racemopentad fraction (mmmm + rrrr) by C-NMR spectrum is in the range of 30 to 70%, and the crystalline block and the amorphous block portion are mixed in the molecular chain. Is controlledAnd the heat of crystal fusion is 10-50 J / gSoft polypropylene resin
Component (c): a copolymer of a vinyl aromatic compound having a glass transition temperature of 0 ° C. or lower and a conjugated diene, or a hydrogenated derivative thereof
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below.
The crystalline polypropylene resin as component (a) constituting the present invention is a propylene homopolymer, a block copolymer of propylene and an α-olefin such as ethylene, butene, hexene, or a random copolymer thereof. Or a mixture thereof, but it is necessary that the crystal melting peak temperature exists only at 130 ° C. or higher.
[0009]
Here, the fact that the crystal melting peak temperature exists only at 130 ° C. or more means that the heat of fusion of the crystal melting peak existing at less than 130 ° C. is less than 1 J / g.
A block copolymer or the like having a crystal melting peak temperature clearly below 130 ° C. is effective in imparting impact resistance, but the microcraze generated upon impact is visually Has the problem of appearing whitened.
[0010]
Next, the soft polypropylene resin as component (b) constituting the present invention is a propylene homopolymer, a block copolymer of propylene and an α-olefin such as ethylene, butene, hexene, or a random copolymer of them. It is arbitrarily selected from a coalescence or a mixture thereof,¹³Stereoregularity in which the sum of the mesopentad fraction and the racemopentad fraction (mmmm + rrrr) by C-NMR spectrum is in the range of 30 to 70%, and a crystalline block and an amorphous block portion are mixed in the molecular chain. Is a propylene polymer controlled.
[0011]
Here, a crystalline block and an amorphous block portion are mixed in the molecular chain. The crystalline block and the amorphous block portion are present in a random and / or block form. In addition, the chain length of each block portion may be arbitrary.
[0012]
Such polymers generally have the properties of rubber elasticity, flexibility, resistance to tearing, good transparency, and isotactic and syndiotactic structures that exhibit rigidity in the molecular chain. It is suitable to achieve the object of the present invention by balancing the proportion of the amorphous block portion of the crystalline block portion and the amorphous block portion of the atactic structure exhibiting elastomeric properties.
[0013]
As for stereoregularity, mesopen is one index indicating the proportion of crystalline block parts.TFraction and racemopenTIt is necessary that the sum (mmmm + rrrr) of the head fraction is in the range of 30 to 70%.
Here, when (mmmm + rrrr) is less than 30%, the crystallinity is too low, and when mixed with the component (a), the sheet becomes too flexible and the surface hardness is lowered, and the scratch resistance tends to be inferior. Further, it is not preferable because the resin sheet is galling when punching is performed on the resin-coated metal plate, or a beard-like resin piece remains on the end surface of the resin sheet after punching. Furthermore, the surface of the sheet becomes sticky, and the raw material itself is easily blocked, which is not preferable in terms of handling properties.
[0014]
On the other hand, when (mmmm + rrrr) exceeds 70%, there are few effects such as improving flexibility, impact resistance, and whitening resistance. It is not preferable that the resin sheet is cracked or cracked or whitened easily.
The mesopentad fraction (mmmm) and racemopentad fraction (rrrr) used in the present invention are¹³It calculates based on the measurement result of a C-NMR (nuclear magnetic resonance) spectrum. That is,¹³The C-NMR spectrum was measured and determined from the signal intensity ratio of each splitting peak (mmmm to mrrm) appearing in the 22.5 ppm to 19.5 ppm region due to the difference in chemical shift due to the stereoregularity of the methyl group. The mmmm (mesopentad fraction) is a solid in which all five methyl groups as side chains are located in the same direction with respect to the main chain of carbon-carbon bonds composed of arbitrary five propylene units. Rrrr (racemopentad fraction) is an alternating structure of five methyl groups as side chains with respect to the main chain of carbon-carbon bonds composed of any five consecutive propylene units. Means a three-dimensional structure located in the opposite direction or a proportion thereof. The assignment of the signal of the methyl group region is as follows. According to Zambelli et al (Macromolecules 8, 687, (1975)).
[0015]
Further, such a soft polypropylene resin has a crystal melting peak temperature of 140 ° C. or higher and a crystal melting calorie of 10 to 50 J / g as measured by a differential scanning calorimeter, and is not suitable for soxhlet extraction with boiling n-heptane. In Soxhlet extraction with a dissolved content of 60% by weight or less and cold xylene, those having an insoluble content of 95% by weight or less are preferably used.
[0016]
Here, when the crystal melting peak temperature is less than 140 ° C., the heat resistance is likely to be lowered. For example, when the surface of the resin sheet is embossed, the heat resistance is lowered, which is not preferable.
Further, when the heat of crystal fusion is less than 10 J / g, when mixed with the component (a), the sheet becomes too flexible and the surface hardness is lowered, and the scratch resistance tends to be inferior. Further, it is not preferable because the resin sheet is galling when punching is performed on the resin-coated metal plate, or a beard-like resin piece remains on the end surface of the resin sheet after punching. Furthermore, the surface of the sheet becomes sticky, and the raw material itself is easily blocked, which is not preferable in terms of handling properties.
[0017]
On the other hand, when it exceeds 50 J / g, there are few effects such as improving flexibility, impact resistance, and whitening resistance, and the resin-coated metal plate was subjected to bending processing, particularly impact contact bending processing at high speed under low temperature conditions. Sometimes the resin sheet is cracked or cracked, or is easily whitened.
[0018]
Also, if the insoluble content by boiling n-heptane exceeds 60% by weight or the insoluble content by cold xylene exceeds 95% by weight, the crystallinity is high, so that it is effective as a modifier, that is, flexibility and impact resistance. Because there are few effects such as improving the property and whitening resistance, the resin sheet is cracked or cracked when the resin-coated metal sheet is bent when the resin-coated metal sheet is bent. It is not preferable.
[0019]
As a method for producing a soft polypropylene resin suitable for the present invention, an inexpensive propylene monomer is used as a main component, various metallocene catalysts (single site catalysts), solid titanium catalysts, etc. are used, and molding processability is good. A method for polymerizing a soft polypropylene resin with controlled stereoregularity efficiently and at low cost has been proposed, and the resin used is not particularly limited as long as it satisfies the gist of the present invention. An example of a commercial product is the product name “REXflex” of Huntsman Polymer Corporation.
[0020]
Next, the component (c) constituting the present invention is a copolymer of a vinyl aromatic compound having a glass transition temperature of 0 ° C. or lower and a conjugated diene or a hydrogenated derivative thereof (hereinafter sometimes referred to as “TPS”). . Such a copolymer generally has rubber elasticity, flexibility, resistance to tearing, and good transparency, and particularly its hydrogenated derivatives are components (a) and (b). And good compatibility, it effectively acts to impart flexibility and improve transparency at low temperatures. However, the glass transition temperature needs to be 0 ° C. or lower, preferably −20 ° C. or lower. When the glass transition temperature exceeds 0 ° C., the effect of imparting flexibility at a low temperature, which is the purpose of adding the component (c), becomes insufficient.
[0021]
Moreover, it is preferable that the ratio of the vinyl aromatic-type compound and conjugated diene of such a copolymer is 3 / 97-40 / 60 by weight ratio. Here, if the vinyl aromatic compound in the copolymer composition is less than 3% by weight, the polymerization productivity such as the rigidity of the copolymer itself is too low and pelletization becomes difficult, and on the other hand, 40% by weight. If it exceeds, the rigidity of the copolymer itself becomes high, and the effect of imparting flexibility at a low temperature, which is the purpose of adding the component (c), tends to be insufficient.
[0022]
Here, styrene is a typical vinyl aromatic compound, but styrene homologues such as α-methylstyrene may also be used. Examples of the conjugated diene include 1,3-butadiene, isoprene, 1,3-pentadiene and the like. Further, as the third component, a small amount of components other than the vinyl aromatic compound and the conjugated diene may be contained. However, the thermal stability and weather resistance when a double bond mainly consisting of vinyl bonds in the conjugated diene moiety remains are extremely poor. To improve this, 80% or more, preferably 95% of the double bonds. It is preferable to use one added with hydrogen.
[0023]
Such copolymers include styrene-butadiene block copolymer elastomer (Asahi Kasei Kogyo Co., Ltd., trade name “Tufprene”), hydrogenated derivatives of styrene-butadiene block copolymer (Asahi Kasei Kogyo Co., Ltd., trade name “Tuftec”). ", Shell Japan Co., Ltd., trade name" Clayton G "), hydrogenated derivative of styrene-butadiene random copolymer (JSR Corporation, trade name" Dynalon "), hydrogenated derivative of styrene-isoprene block copolymer ( (Kuraray trade name "Septon"), styrene-vinylisoprene block copolymer elastomer (Kuraray trade name "Hibler"), etc., and these copolymers are used alone or Two or more kinds can be mixed and used.
[0024]
Among these, a hydrogenated derivative of a styrene / conjugated diene random copolymer having a styrene content of 5 to 25% by weight and a vinyl bond content of the conjugated diene moiety exceeding 60%, preferably 65 to 90% is (a) , (B) It is particularly preferable from the viewpoints of compatibility with the component, imparting flexibility at low temperature, and improving whitening resistance.
[0025]
The detailed contents of hydrogenated derivatives of styrene / conjugated diene random copolymers that can be suitably used in the present invention and the production method thereof are described in JP-A-2-158634, JP-A-2-305814 and JP-A-2-305814. It is disclosed in Japanese Laid-Open Patent Publication No. 3-72512. As a specific example of such a copolymer, a hydrogenated styrene butadiene rubber structure is used, and a material called abbreviation of HSBR is commercially available under the trade name “Dynalon 1320P”.
[0026]
Here, when the color pattern of the resin sheet used for the resin-coated metal plate is a light color system such as white, whitening is not so important, but with a dark color pattern such as black, bending processing, particularly impact It is easy to notice that the part is whitened when processing is applied. This is presumably because light is scattered at the interface between the matrix made of the crystalline polypropylene resin as component (a) and the modifier dispersed therein. Therefore, in such a member in which whitening resistance is regarded as important, the influence of light scattering at the interface between the matrix made of the crystalline polypropylene resin (a) and the modifier dispersed therein. In order to make the average particle size as small as possible, it is desirable to adjust the average dispersed particle size of the dispersed particles to 0.5 μm or less, preferably 0.4 μm or less.
[0027]
In this respect, the soft polypropylene-based resin as the component (b) used in the present invention is a resin whose physical properties are adjusted by controlling the type and degree of stereoregularity. Therefore, it is possible to impart moderate flexibility and mechanically blend the conventionally used elastomer components, or in the form of copolymerizing α-olefin etc. during polymerization. Unlike the polyolefin-based thermoplastic elastomer contained, the compatibility with the component (a) constituting the matrix is remarkably improved, and the matrix that causes whitening of the bent portion by uniformly dispersing at the molecular level Light scattering at the modifier interface can be reduced.
[0028]
However, since the main component of component (b) is propylene and has a glass transition temperature of around −10 ° C. derived from polypropylene, the secondary processing characteristics at room temperature are good, but the secondary processing characteristics at low temperature are good. There are insufficient aspects.
Therefore, in the present invention, the component (c) is further added as needed for the main purpose of further improving the secondary processing characteristics at a low temperature.
If component (c) is added, it will be finely dispersed in the matrix formed by the crystalline polypropylene resin as component (a), and it will be flexible in order not to grow crazes and spherulites generated by impact beyond the wavelength of visible light. It is considered effective for imparting properties, impact resistance, whitening resistance, and the like.
[0029]
As described above, when the component (b) and the component (c) are used in combination, the resin-coated steel sheet has excellent secondary workability such as bending workability and punching workability, whitening resistance, scratch resistance, etc. A taken polyolefin resin sheet can be produced. This is because the component (c) finely dispersed in the matrix formed by the component (a) inhibits the spherulite growth in the component (b) simultaneously with the spherulite growth in the component (a). It is. As described above, the addition of the component (c) brings many advantages. However, the component (c) is generally expensive, and in the case of a transparent and flat sheet, fish eyes derived from the component (c) are conspicuous. Addition of a large amount of component (c) is not preferable from the viewpoints of economy, sheet appearance, physical properties, and the like.
[0030]
In the present invention, in the relationship between the crystalline polypropylene resin in which the crystal melting peak that is the component (a) constituting the matrix exists only at 130 ° C. or higher and the {(b) + (c)} component as a modifier. It is necessary that (a) / {(b) + (c)} = 75 to 90/25 to 10 and (c) ≦ 15 by weight ratio.
Here, when the {(b) + (c)} component as the modifier is less than 10% by weight, the effect of improving flexibility, impact resistance, whitening resistance is small, and the resin-coated metal plate is bent. There is a problem that the resin sheet is cracked or cracked or easily whitened when subjected to processing, particularly impact contact bending at high speed under low temperature conditions.
[0031]
On the other hand, in the composition region where the {(b) + (c)} component as the modifier is more than 25% by weight or the component (c) exceeds 15% by weight, the sheet becomes too flexible and the surface hardness is lowered. However, there is a problem that the scratch resistance tends to be inferior. Further, when the punching process is performed on the resin-coated metal plate, there is a problem that the resin sheet is galvanized or a whisker-like resin piece is likely to remain on the end surface of the resin sheet after the punching process.
In the polyolefin resin sheet of the present invention, other resins and additives such as polyethylene, for example, heat stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, nucleating agents, coloring, to the extent that their properties are not impaired. Various additives such as additives, antibacterial / antifungal agents, antistatic agents, lubricants, flame retardants, fillers and the like may be properly blended. Moreover, in order to improve the designability, printing, embossing, or the like can be appropriately applied to the resin sheet.
[0032]
Next, the manufacturing method of the polyolefin-type resin sheet and resin-coated metal plate of this invention is demonstrated.
As a method for forming a polyolefin-based resin sheet of the present invention, a known method, for example, an extrusion casting method using a T-die, a calendar method, an inflation method, or the like can be adopted. An extrusion casting method using a T die is preferable from the viewpoint of film forming property and stable productivity. The molding temperature in the extrusion casting method using a T-die is appropriately adjusted depending on the flow characteristics and film-forming properties of the composition, but is generally in the range of the melting point to 260 ° C., preferably 180 ° C. to 230 ° C. . The thickness of the polyolefin resin sheet is usually 50 to 500 μm. When the thickness of the sheet is less than 50 μm, when used as a resin-coated metal plate, the performance as a protective layer for the metal plate and the embossing suitability are inferior. On the other hand, when the thickness exceeds 500 μm, secondary processing such as punching as a resin-coated decorative metal plate Processability is apt to be inferior.
[0033]
Next, as a method of adhering the polyolefin resin sheet and the metal plate, there is a method of using an adhesive, a method of heat-sealing without using an adhesive, a method of extrusion coating, and the like, although not particularly limited, for example, After applying a titanium coupling agent, chlorinated polyolefin, acid-modified polyolefin, etc. as a primer treatment liquid to the adhesive surface of the polyolefin resin sheet with the metal plate, the thickness after drying is 2 to 4 μm, and further polyester-based There is a method of applying an epoxy-based adhesive and coating a resin sheet.
[0034]
In this method, commonly used coating equipment such as reverse coater and kiss coater is used for the metal plate, and the adhesive film thickness after drying is about 2 to 4 μm on the metal surface on which the polyolefin resin sheet is bonded. Apply, then dry and heat the coated surface with an infrared heater and hot air heating furnace, and immediately hold the polyolefin resin sheet using a roll laminator while maintaining the metal plate surface temperature above the melting point of the polyolefin resin sheet, A resin-coated metal plate can be obtained by cooling.
[0035]
Various metal plates such as hot-rolled steel plate, cold-rolled steel plate, hot-dip galvanized steel plate, electrogalvanized steel plate, tin-plated steel plate, stainless steel plate and the like can be used as the metal plate subject to the present invention. It may be used after
[0036]
【Example】
In order to describe the present invention more specifically and in detail, the following examples are given, but the present invention is not limited to these examples. In addition, the measurement standard of the physical property of the resin coating metal plate shown to the Example and the comparative example and the test method are as follows.
[0037]
(1) Glass transition temperature (Tg), crystal melting heat, crystal melting peak temperature
Using DSC-7 manufactured by Perkin Elmer, a 10 mg sample was measured and measured at a heating and cooling rate of 10 ° C./min according to JIS-K7121 and JIS-K7122.
[0038]
(2) Melt flow-G (MFR)
According to JIS-K7210, the measurement was performed under conditions of a test temperature of 230 ° C. and a test load of 2.16 kgf.
[0039]
(3) MesopenTFraction (mmmm), racemopenTFraction (rrrr)
JNM-GSX-270 (manufactured by JEOL Ltd.)¹³C-nuclear magnetic resonance frequency (67.8 MHz) was measured under the following conditions.
[0040]
Measurement mode:¹H-complete decoupling
Pulse width: 8.6 microseconds
Pulse repetition time: 30 seconds
Integration count: 7200 times
Solvent: Mixed solvent of orthodichlorobenzene / heavy benzene (80/20% by volume)
Sample concentration: 100mg / 1ml solvent
Measurement temperature: 130 ° C
Where each penTThe fraction of¹³It was determined by measuring the splitting peak in the methyl group region of the C-nuclear magnetic resonance spectrum. Further, the assignment of the signal of the methyl group region is as follows. According to Zambelli et al (Macromolecules 8, 687, (1975)).
[0041]
(4) Bending processability
An impact adhesion bending test is performed on the resin-coated metal plate, and the surface state of the decorative sheet of the bent portion is visually determined. (○) indicates that there is almost no change, (△) indicates that there is a slight crack (△), What occurred was displayed as (x). The impact adhesion bending test was performed as follows. Samples of 50 mm x 150 mm were prepared from the length direction and width direction of the coated metal plate, kept at 23 ° C or 0 ° C for 1 hour or longer, and then bent to 180 ° (inner bending radius 2 mm) using a bending tester. A cylindrical weight having a diameter of 75 mm and a mass of 5 kg was dropped on the sample from a height of 50 cm.
[0042]
(5) Whitening resistance
Similarly to the bending workability of (4), an impact adhesion bending test is performed on the coated metal plate, the surface state of the resin sheet in the bent portion is visually determined, and the whitening phenomenon is hardly noticeable (O), The case where the whitening phenomenon is conspicuous is indicated by (Δ), and the case where the whitening phenomenon is conspicuous is indicated by (X).
[0043]
(6) Punching workability
Using a press machine, punching and bending is performed on a coated metal plate of 300 mm x 300 mm from the resin sheet surface so that the opening shape is 100 mm x 200 mm (corner part R10) and the bending width is 10 mm, and the surface state of the decorative sheet in the processed part is changed. Judgment was carried out visually, and no galling or whiskers were produced, and those that were cleanly processed were indicated as (◯), those that slightly rubbed or bearded (Δ), and those that noticed galling or whiskers as (×).
[0044]
(7) Surface hardness
Using a 3B pencil, draw a wire with a load of 500 g while maintaining an angle of 45 ° with respect to the resin sheet surface of the 80 mm × 60 mm coated metal plate, and visually determine the surface state of the resin sheet in the drawing portion, Those that were not scratched at all were indicated as (◯), those that remained slightly marked (Δ), and those that were clearly scratched (×).
[0045]
[Examples 1 to2And Comparative Examples 1 to 6] Each component was kneaded so as to be homogeneous using a twin-screw kneading extruder equipped with a T-die together with a black colorant in the proportions (% by weight) shown in Table 1, and the thickness. A 150 μm polyolefin resin sheet was formed. Next, after applying the acid-modified polyolefin as a primer treatment liquid to the adhesive surface of the obtained sheet with the metal plate to a thickness of 2 to 4 μm after drying, a commercially available polyester for polyvinyl chloride coated metal plate The adhesive is applied to the metal surface so that the adhesive film thickness after drying is about 2 to 4 μm, and then the coated surface is dried and heated by a hot air heating furnace and an infrared heater to obtain a galvanized steel sheet (thickness 0). .41 mm) while maintaining the surface temperature at or above the melting point of the polyolefin resin sheet, immediately coated the polyolefin resin sheet with a roll laminator and cooled to prepare a resin-coated steel sheet, and evaluated each item described above. . The results are summarized in Table 1.
[0046]
In addition, each raw material used in Table 1 is as follows.
Crystalline polypropylene resin A [“NOVATEC PP EA7” manufactured by Nippon Polychem Co., Ltd. Crystal melting peak temperature: 162 ° C., crystal melting heat amount: 112 J / g]
Crystalline Polypropylene Resin B ["Novatec PP EC7" manufactured by Nippon Polychem Co., Ltd. Crystal melting peak temperature: 119 ° C and 163 ° C, heat of crystal melting; 2 J / g and 98 J / g, respectively]
Soft polypropylene resin (I) [propylene content; 98.5 mol%, ethylene content; 1.5 mol%, mmmm; 37.4%, rrrr; 11.4%, MFR; 11.0 g / 10 min, Tg -10 ° C, crystal melting peak temperature; 149 ° C, heat of crystal melting; 23 J / g].
[0047]
Soft polypropylene resin (II) [propylene content: 100 mol%, mmmm; 52.6%, rrrr; 10.7%, MFR; 2.0 g / 10 min, Tg: -7 ° C, crystal melting peak temperature: 156 ° C, heat of crystal melting; 42 J / g]
Soft polypropylene resin (III) [propylene content: 100 mol%, mmmm; 64.3%, rrrr; 8.2%, MFR; 3.0 g / 10 min, Tg; -6 ° C, crystal melting peak temperature: 158 ° C, heat of crystal melting; 55 J / g]
TPO ["PERR T310J" manufactured by Tokuyama Corporation Propylene content; 88 mol%, ethylene content; 12 mol%, MFR; 1.5 g / 10 min, Tg; -25 ° C, crystal melting peak temperature; 156 ° C., heat of crystal melting; 32 J / g]
TPS ["Dynalon 1320P" manufactured by Nippon Synthetic Rubber Co., Ltd. Styrene content: 10%, vinyl bond content of conjugated diene moiety: 78%, specific gravity: 0.89, MFR: 3.5 g / 10 min, Tg: -50 ° C ]
[Table 1]

[0048]
As is apparent from Table 1, a raw material that has a crystal melting peak temperature clearly below 130 ° C. is used as the crystalline polypropylene resin constituting the matrix (Comparative Example 1), or a conventional modifier as a modifier. It can be seen that when TPO which is a polyolefin-based thermoplastic elastomer used is used (Comparative Example 2), it is not possible to express whitening property particularly during low-temperature processing.
[0049]
Even if a soft polypropylene resin with controlled stereoregularity in which crystalline blocks and amorphous block parts are mixed in the molecular chain is used as a modifier, the stereoregularity and amount of addition are specified. If they are not within the range, there are problems in terms of bending workability, punching workability, and surface hardness (Comparative Examples 3 to 5).
Further, the addition of a large amount of TPS as a modifier has a problem in terms of scratch resistance although the secondary processing characteristics are improved (Comparative Example 6).
[0050]
On the other hand, Examples 1 to2As described above, a crystalline polypropylene resin having a crystal melting peak temperature of only 130 ° C. or more and a soft polypropylene resin having a specific stereoregularity as a modifieras well asFor TPS blended in the specified amount range, bending workability, whitening resistance, punching workability, surface hardnessIt can be seen that the balance is excellent.
[0051]
【The invention's effect】
According to the present invention, it is possible to provide a polyolefin-based resin-coated metal sheet having an excellent balance of secondary processability such as bending processability and punching processability as a resin-coated metal sheet, whitening resistance, and scratch resistance. it can.

Claims (3)

It comprises a mixture of the component (a) constituting the following matrix, the component (b) and the component (c) as modifiers, and the proportion of each component is (a) / {(b) + (c) } = 75 to 90/25 to 10, and (c) ≦ 15.
(A) component; crystalline polypropylene resin (b) component having a crystal melting peak temperature of only 130 ° C. or higher; the sum (mmmm + rrrr) of mesopentad fraction and racemopentad fraction by ¹³ C-NMR spectrum is 30 to 70% A soft polypropylene resin (c) in which the stereoregularity in which a crystalline block and an amorphous block portion are mixed in the molecular chain is controlled and the heat of crystal fusion is 10 to 50 J / g. ) Component; Copolymer of vinyl aromatic compound having glass transition temperature of 0 ° C. or less and conjugated diene or hydrogenated derivative thereof It comprises a mixture of the component (a) constituting the following matrix, the component (b) and the component (c) as modifiers, and the proportion of each component is (a) / {(b) + (c) } = 75-90 / 25-10, and (c) <= 15 It is coat | covered with the polyolefin resin sheet characterized by the above-mentioned. The resin-coated metal plate characterized by the above-mentioned.
(A) component; crystalline polypropylene resin (b) component having a crystal melting peak temperature of only 130 ° C. or higher; the sum (mmmm + rrrr) of mesopentad fraction and racemopentad fraction by ¹³ C-NMR spectrum is 30 to 70% A soft polypropylene resin (c) in which the stereoregularity in which a crystalline block and an amorphous block portion are mixed in the molecular chain is controlled and the heat of crystal fusion is 10 to 50 J / g. ) Component; Copolymer of vinyl aromatic compound having glass transition temperature of 0 ° C. or less and conjugated diene or hydrogenated derivative thereof   Component (c) is a copolymer of a vinyl aromatic compound and a conjugated diene, or a hydrogenated dielectric thereof, wherein the styrene content is 5 to 25% by weight and the vinyl bond content of the conjugated diene part exceeds 60%. The polyolefin resin sheet or resin-coated metal plate according to claim 1 or 2, which is a hydrogenated derivative of a conjugated diene random copolymer.