JP2019061162A - Reflector - Google Patents

Abstract

To provide a reflector which is excellent in reflection and conceal performances, has a uniform porous structure even when containing high concentration of a filler, and is suitable as a liquid crystal display, a lighting fixture, a lighting signboard, or the like.SOLUTION: The reflector is provided that is composed of a stretched sheet comprising a layer composed of a thermoplastic resin composition (A). The thermoplastic resin composition (A) contains a polypropylene resin (a1), a low-elastic-modulus olefinic resin (a2) with an elastic modulus of 100 MPa or more and 1050 MPa or less, and a filler.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a reflector. More particularly, the present invention relates to a porous film which is excellent in reflection performance and concealment performance and is suitable for a reflective material such as a liquid crystal display, a lighting fixture or a lighting sign.

Polyolefin films are used in various applications such as industrial materials, packaging materials, optical materials, electrical materials, etc. because they have excellent mechanical properties, thermal properties, electrical properties and optical properties.
Among them, a porous film in which pores are provided in a polyolefin film has excellent properties such as permeability and low specific gravity in addition to the above-mentioned properties as a polyolefin film, and therefore, separators and various separation membranes for batteries and electrolytic capacitors Various studies have been conducted for a wide variety of applications such as clothing, moisture-permeable waterproof films in medical applications, reflectors for flat panel displays, and thermal transfer recording sheets.

  A dry method can be mentioned as one of the methods of making a polyolefin film porous. As a representative example of the dry method, for example, by employing low temperature extrusion and high draft ratio at the time of melt extrusion, the lamellar structure in the sheeted film before drawing is controlled, and this is uniaxially drawn to form a lamellar interface. A so-called lamella stretching method has been proposed to generate a void by causing cleavage at For example, in Patent Document 1, a film-like molded product comprising crystalline polypropylene and a propylene-α-olefin copolymer dispersed in crystalline polypropylene is stretched in at least one direction to form a propylene-α-olefin co-polymer. Disclosed is a method of forming pores in communication with a polymer region to form a porous film.

  As another dry method, a large amount of immiscible resin is added as particles to inorganic particles or polyolefin which is a matrix resin, and a sheet is formed to generate cleavage at the interface between the particles and the polypropylene resin by stretching. Methods of forming air gaps have also been proposed. For example, Patent Document 2 discloses a method of obtaining a porous film or the like by using a propylene-based resin composition containing a specific propylene-based random block copolymer and a filler, and Patent Document 3 discloses a polyolefin There is disclosed a method of obtaining a porous resin sheet by stretching a polyolefin resin sheet containing 100 to 300 parts by weight of finely divided inorganic filler with respect to 100 parts by weight of a base resin.

  Furthermore, in these methods, voids are formed in the film by utilizing the difference in crystal density between the α-form crystals (α crystals) and the β-form crystals (β crystals), which are crystal polymorphs of polypropylene, and the crystal transition. There has also been proposed a combination of so-called β crystal methods. For example, Patent Document 4 discloses a method of obtaining a porous polypropylene film having high porosity by using a polyolefin resin comprising a polypropylene resin having β crystal activity and an ethylene / α-olefin copolymer. No. 5 discloses a method of obtaining a biaxially oriented white polypropylene film having a porous layer with high porosity, in which fine voids are formed by the combination of a polypropylene resin having β crystal activity and fine dispersed particles. .

JP, 2005-120140, A JP, 2009-84303, A JP-A-8-262208 JP, 2008-248231, A International Publication WO2007 / 132876

In the conventionally known reflectors, while it is necessary to increase the concentration of the filler, ie, the filler, in order to increase the reflectance, when the concentration of the filler is increased, the filler contained in the high concentration prevents homogeneous stretching, Since the voids tend to form a non-uniform porous structure locally formed, excessive stretching and elongation may be added to the formed voids, and the porous structure may be broken.
Further, as disclosed in Patent Documents 4 and 5, etc., in the method combining β crystal method, etc., the light transmittance is because the porosity of the film is too high or the amount of dispersed particles is insufficient. It becomes a high quality film, and there was a case where concealment performance was not obtained.

  Therefore, an object of the present invention is to provide a new reflector capable of forming a uniform porous structure even when containing a high concentration of filler and having both excellent reflection performance and concealment performance. It is to provide.

The present invention is a reflective material comprising a stretched sheet provided with a layer comprising a thermoplastic resin composition (A), wherein the thermoplastic resin composition (A) is a polypropylene resin (a1), and the elastic modulus is 100 MPa or more and 1050 MPa. The low elastic modulus olefin resin (a2) which is the following, and the reflector containing a filler are proposed.
The present invention also proposes a laminated reflector having a layer mainly composed of the thermoplastic resin composition (B) on at least one surface of the above-mentioned reflector.

  The reflector and the laminated reflector proposed by the present invention are a single layer comprising a resin composition containing a polypropylene resin (a1), a low elastic modulus olefin resin (a2) having a predetermined elastic modulus, and a filler. A reflective material obtained by stretching a sheet of a layer or a laminate, and since it is possible to disperse stress that tends to be concentrated locally in the stretching step in manufacturing the reflective material, a filler is used. Even if contained in high concentration, a uniform porous structure can be formed, and both excellent reflection performance and hiding performance can be provided. Therefore, the reflective material and the laminated reflective material proposed by the present invention can be suitably used as a reflective material for a liquid crystal display, a lighting fixture, or a lighting signboard.

It is a cross-sectional image (500 times) of the extending | stretching direction after longitudinal stretch about the laminated film of Example 2. FIG. It is a cross-sectional image (5000 times) of the extending | stretching direction after biaxial stretching about the laminated film of Example 2. FIG. It is a cross-sectional image (500 times) of the extending | stretching direction after longitudinal stretch about the laminated film of the comparative example 1. FIG. It is a cross-sectional image (5000 times) of the extending direction after biaxial stretching about the lamination film of comparative example 1.

  Hereinafter, an example of the embodiment of the present invention will be described in detail. However, the present invention is not limited to the embodiment described below, and can be arbitrarily modified and implemented without departing from the scope of the present invention.

[This reflector]
The reflector ("the present reflector") according to an example of the embodiment of the present invention is a stretched sheet provided with a layer comprising a thermoplastic resin composition (A), that is, a layer comprising a thermoplastic resin composition (A) It is a reflective material which consists of a sheet which extends the sheet of the single layer or lamination provided at least uniaxially.

<Thermoplastic resin composition (A)>
The thermoplastic resin composition (A) is a composition containing a polypropylene resin (a1), a low elastic modulus olefin resin (a2) and a filler.

(Polypropylene resin (a1))
In the present reflector, the polypropylene resin (a1) can contribute to the role of securing high porosity and mechanical strength of the reflector. The polypropylene-based resin (a1) has a predetermined hardness, in other words, an elastic modulus, so that it can be peeled off at the interface between the filler and the resin by stretching to play a role in forming pores. At the same time, if the polypropylene resin (a1) produces β crystals, it is preferable to conduct stretching to easily form micropores and to achieve high porosity.

The polypropylene resin (a1) has at least a propylene unit, and may be an olefin resin other than the low elastic modulus olefin resin (a2) described later.
Among them, the polypropylene-based resin (a1) is preferably a polypropylene-based resin in which the proportion of propylene units is 50% by mass or more, more preferably 60% by mass or more, still more preferably 80% by mass or more, particularly preferably 90 The upper limit is 100% by mass. When the polypropylene resin (a1) has a propylene unit in the above range, the present reflector is likely to have high porosity and mechanical strength to be improved, and the addition of a β crystal nucleating agent to be described later causes the β crystal activity to be increased. It tends to be higher.

  Specific examples of the polypropylene resin (a1) include homopolypropylene (propylene homopolymer), random copolymer or block copolymer of propylene and α-olefin other than propylene, or a mixture of these. Can. Examples of α-olefins other than propylene include ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene and the like. The species or two or more species can be used in combination. Among these, homopolypropylene (propylene homopolymer) is preferably used from the viewpoint of increasing the porosity of the reflective material and securing mechanical strength.

The polypropylene resin (a1) preferably has an isotactic pentad fraction (mm mm fraction) exhibiting stereoregularity of 80% or more, more preferably 83% or more, and still more preferably 85% or more. is there.
If the isotactic pentad fraction is 80% or more, the mechanical strength of the film can be maintained. On the other hand, the upper limit of the isotactic pentad fraction is not limited. The upper limit value of industrially obtained polypropylene resins at the present time is usually 99% or less, preferably 98% or less, more preferably 97% or less. This is not the case in the future when a more regular polypropylene-based resin is developed.
The "isotactic pentad fraction (mmmm fraction)" refers to five methyl groups that are side chains with respect to the main chain of carbon-carbon bond composed of arbitrary five consecutive propylene units. All mean a three-dimensional structure or its ratio located in the same direction. Assignment of signals in the methyl group region is described in A.I. According to Zambellietal (Macromolecules 8, 687, (1975)).

The polypropylene resin (a1) preferably has a ratio (Mw / Mn) of number average molecular weight (Mn) to mass average molecular weight (Mw) of 2.0 to 10.0, and more preferably 2.0 to 10.0. It is 8.0, more preferably 2.0 to 6.0.
The smaller the Mw / Mn, the narrower the molecular weight distribution. If Mw / Mn is 2.0 or more, extrusion moldability can be suitably maintained, and production tends to be easy industrially. On the other hand, when the Mw / Mn is 10.0 or less, the amount of the low molecular weight component is not too much, so that it is possible to suppress the decrease in the mechanical strength of the reflector.
In addition, the value of "Mw" and "Mn" can be measured as a polystyrene conversion value using GPC (gel permeation chromatography).

The melt flow rate (MFR) of the polypropylene resin (a1) is not particularly limited. Among them, 0.5 to 15 g / 10 min is preferable, and 1.0 to 10 g / 10 min is more preferable.
If the MFR of the polypropylene-based resin (a1) is not less than the lower limit value, the melt viscosity of the resin at the time of molding is high, and sufficient productivity tends to be ensured. On the other hand, when the MFR is equal to or less than the upper limit value, the mechanical strength of the obtained reflector can be sufficiently maintained.
MFR is a value measured under the conditions of a temperature of 230 ° C. and a load of 2.16 kgf (21.18 N) according to JIS K7210.

The elastic modulus of the polypropylene resin (a1) is preferably more than 1050 MPa and 2100 MPa or less.
If the modulus of elasticity of the polypropylene-based resin (a1) exceeds 1050 MPa, peeling is likely to occur at the interface between the filler and the resin at the time of stretching, which is preferable because high porosity can be easily achieved. Moreover, if the elasticity modulus of a polypropylene resin is 2100 MPa or less, since the film forming stability in an extending process can be ensured, it is preferable.
From this point of view, the modulus of elasticity of the polypropylene resin (a1) is preferably more than 1050 MPa and 2100 MPa or less, and more preferably 1200 MPa or more or 2000 MPa or less, and more preferably 1500 MPa or more or 1900 MPa or less.

  In the present invention, "elastic modulus" means a tensile elastic modulus measured under the conditions defined in JIS K6921-2.

  The method for producing the polypropylene resin (a1) is not particularly limited, and known polymerization methods using known polymerization catalysts, for example, multisite catalysts represented by Ziegler-Natta type catalysts and metallocene catalysts And polymerization methods using a single site catalyst.

  Examples of polypropylene resins (a1) include commercial products such as "Novatec PP" and "WINTEC" manufactured by Nippon Polypropylene, "Sumitomo Noblen" manufactured by Sumitomo Chemical, "Prime Polypro" manufactured by Prime Polymer, and "Sun Aroma" manufactured by Sun Aroma. It is possible to appropriately select and use appropriate products from among the products.

The thermoplastic resin composition (A) preferably has β crystal activity.
Here, “having β crystal activity” means that the thermoplastic resin composition (A) forms β crystals in the state before stretching.
If the thermoplastic resin composition (A) generates β crystals in the state before stretching, the micropores can be easily formed by stretching. For this reason, it is preferable because it is possible to obtain a reflective material having a high porosity, in combination with the pores formed by interfacial peeling between the resin contained in the thermoplastic resin composition (A) and the filler.

The presence or absence of β crystal activity in the thermoplastic resin composition (A) can be confirmed by measurement using a differential scanning calorimeter or an X-ray diffractometer.
As a method of confirming the β crystal activity by a differential scanning calorimeter, the thermoplastic resin composition (A) is heated from 25 ° C. to 240 ° C. at 10 ° C./minute and then held for 1 minute, then 240 ° C. to 25 ° C. The temperature is lowered at 10 ° C / min to 10 ° C, held for 1 minute, and when the temperature is raised again at 25 ° C to 240 ° C at 10 ° C / min, a crystalline melting peak (Tmβ) derived from β crystals is detected. You can check it with

  Further, the presence or absence of β crystal activity can also be confirmed by a diffraction profile obtained by wide-angle X-ray diffraction measurement. As the method, heat treatment is performed at a temperature (170 ° C. to 190 ° C.) exceeding the melting point of the thermoplastic resin composition (A), and then slowly cooled to form and grow β crystals. Make a measurement. When the diffraction peak derived from the (300) plane of the β crystal of the polypropylene resin is detected in the range of 2θ = 16.0 ° to 16.5 °, it can be judged that there is β crystal activity.

For details on the β crystal structure and wide-angle X-ray diffraction of polypropylene-based resins, see Macromol. Chem. 187, 643-652 (1986), Prog. Polym. Sci. Vol. 16, 361-404 (1991), Macromol. Symp. 89, 499-511 (1995), Macromol. Chem. 75, 134 (1964), and the references cited in these documents.
In the case where the present reflector is a laminate (laminated reflector) described later, the β crystal activity may be measured by a differential scanning calorimeter or an X-ray diffractometer as the whole laminated reflector.

  As a method of obtaining the β crystal activity of the thermoplastic resin composition (A), a method of adding polypropylene treated to generate a peroxide radical as described in Japanese Patent No. 3739481, and in the composition The method of adding a beta crystal nucleating agent etc. can be mentioned.

  In the present reflector, in order to impart β-crystal activity to the thermoplastic resin composition (A), it is preferable to include a β-crystal nucleating agent in the thermoplastic resin composition (A).

The β crystal nucleating agent is not limited as long as it can increase the generation and growth of β crystals of the thermoplastic resin composition (A). For example, amide compounds; tetraoxaspiro compounds; quinacridones; iron oxide having nanoscale size; potassium 1,2-hydroxystearate, magnesium benzoate, magnesium succinate, magnesium phthalate, magnesium pimelate, calcium pimelate sodium, Alkali or alkaline earth metal salts of carboxylic acids represented by barium pimelic acid and the like; aromatic sulfonic acid compounds represented by sodium benzenesulfonate and sodium naphthalenesulfonate; di or tri ester of di- or tribasic carboxylic acid Class 2: Phthalocyanine based pigments represented by Phthalocyanine Blue etc .; Binary system compound comprising Component A which is an organic dibasic acid and Component B which is an oxide, hydroxide or salt of Group IIA metal of the periodic table; cyclic Phosphorus compound Such compositions can be mentioned of magnesium compound. Other specific types of nucleating agents are described in JP-A Nos. 2003-306585, 6-289566, and 9-194650.
The β crystal nucleating agent may be used in combination of two or more.

As a commercial item of the β crystal nucleating agent, “NJ Star NU-100” manufactured by Shin Nippon Rika Co., Ltd. may be mentioned. In addition, as a polypropylene resin to which a β crystal nucleating agent is added, “Bepol B-022 SP” manufactured by Aristech, “Beta (β) -PPBE 60-7032” manufactured by Borealis, “BNX BETAPP-LN” manufactured by Mayzo, etc. may be mentioned. Be
In the case where the polypropylene-based resin is the one to which the β crystal nucleating agent is added in advance, the values of Mn, Mw, MFR and elastic modulus of the polypropylene resin (a1) described above include the β crystal nucleating agent It refers to the value of polypropylene resin.

The proportion of the β crystal nucleating agent added to the thermoplastic resin composition (A) needs to be appropriately adjusted depending on the type of the β crystal nucleating agent, the type of the polypropylene resin (a1), and the like. Among them, 0.0001 to 5.0 parts by mass, more preferably 0.001 to 3.0 parts by mass with respect to 100 parts by mass of the polypropylene resin (a1), and even more preferably 0.01 to 1 part by mass or more. The β crystal nucleating agent is preferably contained in a proportion of 0 parts by mass or less, and more preferably 0.03 parts by mass or more, or 0.15 parts by mass or less.
If the content of the β crystal nucleating agent is not less than the above lower limit value, β crystals are sufficiently generated in the polypropylene resin (a1) at the time of film formation of the thermoplastic resin composition (A) and fine and uniform empty by drawing. It is preferable because a reflective material in which holes are sufficiently formed can be obtained. In addition, if the content of the β crystal nucleating agent is less than or equal to the above upper limit, excessive vacancy formation can be suppressed, and as a result, a reflector having high mechanical strength and excellent in reflection performance and concealment performance can be obtained. . Moreover, it is preferable because the bleeding out of the β crystal nucleating agent to the surface of the reflector is also suppressed.

(Low modulus olefin resin (a2))
The low elastic modulus olefin resin (a2) is preferably an olefin resin having a modulus of 100 MPa or more and 1050 MPa or less.

In this reflection, the low elastic modulus olefin resin (a2) has a role to control the porosity to an appropriate range by suppressing the formation of excessive pores as well as making the porous structure of the reflector uniform, and the reflection The material can be provided with appropriate flexibility, and can play a role in improving fracture resistance and flex resistance.
In addition, since the low elastic modulus olefin resin (a2) ductiles the thermoplastic resin composition (A), mechanical stress tends to be locally concentrated particularly at the interface with the filler when it is stretched. Furthermore, when the polypropylene resin (a1) forms β crystals, it absorbs the stress that tends to concentrate locally on the β crystal portion, and makes it uniform throughout the thermoplastic resin composition (A) It is considered to be responsible for the action. As a result, it plays a role of controlling the porosity to an appropriate range by suppressing the formation of an excessive number of pores and the uniformization of the porous structure in the present reflector.
That is, by containing the low elastic modulus olefin resin (a2) in the thermoplastic resin composition (A), even when the filler is contained at a high concentration, uniform porous structure and high porosity can be realized. can do.

  From this point of view, the elastic modulus of the low elastic modulus olefin resin (a2) is preferably 100 MPa or more and 1050 MPa or less, and more preferably 200 MPa or more or 900 MPa or less, and more preferably 300 MPa or more or 700 MPa or less.

The low elastic modulus olefin resin (a2) is not limited as long as it is formed by polymerization of an olefin monomer and the elastic modulus is 100 MPa or more and 1050 MPa or less. For example, at least one selected from polypropylene-based resins such as homopolypropylene, propylene-based random copolymer and propylene-based block copolymer, and polyethylene-based resins such as high density polyethylene, low density polyethylene, linear low density polyethylene, and ethylene-α-olefin copolymer One type of olefin resin can be mentioned.
Among these, as the low elastic modulus olefin resin (a2), a propylene random copolymer, a low density polyethylene, and a linear low density polyethylene are preferable, and a propylene random copolymer is preferable in terms of affinity with the polypropylene resin (a1). More preferable. The propylene-based random copolymer is preferable because it has a high affinity to the polypropylene-based resin (a1), and the effect of softening the thermoplastic resin composition (A) is high.

The melt flow rate (MFR) of the low elastic modulus olefin resin (a2) is not particularly limited. Among them, it is preferably 1.0 to 30 g / 10 min, and more preferably 3.0 g / 10 min or more or 15 g / 10 min or less.
If MFR is more than the said lower limit, when melt-mixing with a polypropylene resin (a1) and extruding, since kneading | mixing and film forming property will be stabilized, it is preferable. On the other hand, if MFR is below the said upper limit, since the mechanical strength of the reflector obtained can fully be ensured, it is preferable. MFR is a value measured under the conditions of a temperature of 230 ° C. and a load of 2.16 kgf (21.18 N) according to JIS K7210.

  The method for producing the propylene-based random copolymer is not particularly limited, and known polymerization methods using known polymerization catalysts, for example, multisite catalysts represented by Ziegler-Natta type catalysts and metallocene catalysts are exemplified. And polymerization methods using a single-site catalyst.

  Examples of propylene-based random copolymers are commercially available such as "Novatec PP" and "WINTEC" manufactured by Nippon Polypropylene, "Sumitomo Noblen" manufactured by Sumitomo Chemical, "Prime Polypro" manufactured by Prime Polymer, and "Sun Aroma" manufactured by Sun Aroma. Appropriate items can be selected and used from among the existing products.

The blending ratio of the low elastic modulus olefin resin (a2) is not limited. 5 to 90% by mass, in particular 5 to 90% by mass, among them 10% to 75% by mass, among them, relative to the total amount of the polypropylene resin (a1) and the low elastic modulus olefin resin (a2) It is preferable to contain the low elastic modulus olefin resin (a2) in a proportion of 15% by mass or more and 50% by mass or less.
If the blending ratio of the low elastic modulus olefin resin (a2) is not less than the lower limit value, the thermoplastic resin composition (A) is made ductile to absorb the stress applied when it is stretched, and the thermoplastic resin It becomes possible to perform the effect | action which makes the whole composition (A) uniform. Furthermore, flexibility, fracture resistance, and bending resistance can be imparted to the present reflector. On the other hand, if the blend ratio of the low elastic modulus olefin resin (a2) is equal to or less than the above upper limit, the hardness of the thermoplastic resin composition (A) is secured, and peeling occurs at the interface with the filler when stretching is performed. In the case where the polypropylene resin (a1) produces β crystals, it does not inhibit the formation of micropores when the polypropylene resin (a1) is stretched, which is preferable.

(Filler)
The thermoplastic resin composition (A) preferably contains a filler in order to increase the porosity of the reflective material. When the reflector contains a filler, by stretching, peeling occurs at the interface between the resin contained in the thermoplastic resin composition (A) and the filler, and pores can be easily formed.

  The type of filler contained in the thermoplastic resin composition (A) is not limited. For example, inorganic fine powder, organic fine powder and the like can be exemplified.

  Examples of the inorganic fine powder include calcium carbonate, magnesium carbonate, barium carbonate, magnesium sulfate, barium sulfate, calcium sulfate, zinc oxide, magnesium oxide, calcium oxide, calcium oxide, titanium oxide, zinc oxide, alumina, aluminum hydroxide, hydroxyapatite, Silica, mica, talc, kaolin, clay, glass powder, asbestos powder, zeolite, siliceous silica and the like can be mentioned. These may be used alone or in combination of two or more.

As said organic fine powder, a polymer bead, a polymer hollow particle etc. can be mentioned, for example, These can be used together by any 1 type or 2 types or more.
Furthermore, inorganic fine powder and organic fine powder may be used in combination.

In particular, in order to obtain a reflective material excellent in reflective performance and hiding performance, a filler capable of securing a large difference in refractive index from the resin contained in the thermoplastic resin composition (A) is preferable. From that point of view, it is preferable that a filler having a refractive index of 1.6 or more, specifically, at least one selected from calcium carbonate, barium sulfate, titanium oxide, and zinc oxide be included.
Among them, titanium oxide has a very high refractive index among the fillers, and the difference in refractive index with the resin contained in the thermoplastic resin composition (A) is large, and the effect of scattering and reflection at the interface between the two leads to reflection performance and concealment performance. It is preferable because it can be an excellent reflector.
As titanium oxide, for example, commercially available products such as Ishihara Sangyo Co., Ltd., Chemers Inc., KRONOS Inc. can be used.

The average particle size (D50) of the filler is not limited. The thickness is preferably 0.05 μm or more, more preferably 0.1 μm or more, still more preferably 0.15 μm or more, while preferably 15 μm or less, more preferably 10 μm or less, still more preferably 5 μm or less, particularly preferably 2 μm or less It is desirable to have.
If the particle size of the filler is not less than the above lower limit value, the dispersibility in the thermoplastic resin composition (A) tends to be able to be secured. In addition, when the particle size of the filler is equal to or less than the upper limit value, the size of the pores formed around the filler does not become excessive, and it tends to be possible to obtain a reflective material having a dense porous structure.

When titanium oxide is used as the filler, the average particle diameter (D50) is preferably 0.05 μm or more and 15 μm or less, and more preferably 0.15 μm or more or 0.50 μm or less.
If the average particle diameter (D50) of titanium oxide is in this range, the reflectance of light at a wavelength of 420 to 600 nm tends to be able to be improved.
The average particle diameter (D50) of the filler is D50 determined from the volume-based particle size distribution measured by a dynamic light scattering method or the like.

The content of the filler is preferably 50% by mass or more and 90% by mass or less based on the total mass of the thermoplastic resin composition (A), and more preferably 55% by mass or more or 80% by mass or less, among them 60% by mass More preferably, it is 70 mass% or less.
In the present reflector, by including the low elastic modulus olefin resin (a2) in the thermoplastic resin composition (A), even when the filler is contained at a high concentration, the uniform porous structure and high porosity are obtained. Can be made possible. And if the compounding ratio of a filler is more than the said lower limit with respect to the whole mass of a thermoplastic resin composition (A), it exists in the tendency which can make the porosity of a reflector high. In addition, the reflectivity tends to be improved due to the difference in refractive index between the resin and the holes. On the other hand, when the blending ratio of the filler is equal to or less than the upper limit value, the dispersibility in the thermoplastic resin composition (A) tends to be secured. In addition, excessive void formation can be suppressed, as a result, mechanical strength can be secured, and a reflector having excellent reflection performance and shielding performance can be obtained.

  In order to impart particularly excellent reflection performance and concealment performance to the present reflector, 30 parts by mass or more of the total mass of 100 parts by mass of the inorganic fine powder contained in the thermoplastic resin composition (A) It is preferred to contain titanium oxide in proportion. Moreover, when using together an organic fine powder and an inorganic fine powder, it is preferable to contain a titanium oxide in the ratio of 30 mass parts or more with respect to the total mass 100 mass parts.

  In the filler contained in the thermoplastic resin composition (A), in order to improve the dispersibility, the surface of the filler is treated with a silicon compound, a polyhydric alcohol compound, an amine compound, a fatty acid, a fatty acid ester, etc. Can be used.

(Other ingredients)
The thermoplastic resin composition (A) may contain another resin as long as it contains a polypropylene resin (a1) and a low elastic modulus olefin resin (a2) as main components.
That is, the total mass ratio of the polypropylene resin (a1) and the low elastic modulus olefin resin (a2) is 50% by mass or more, preferably 75% by mass or more, and more preferably 85% by mass of the thermoplastic resin composition (A). Other resins may be contained as long as it accounts for at least%, more preferably at least 90% by mass, particularly preferably at least 95% by mass (including 100% by mass).

  Also, the thermoplastic resin composition (A) may contain other components other than the polypropylene resin (a1), the low elastic modulus olefin resin (a2), and the filler, as long as the effects of the present invention are not impaired. Good. For example, antioxidants, light stabilizers, heat stabilizers, dispersants, UV absorbers, fluorescent brighteners, compatibilizers, lubricants, α-crystal nucleating agents and other additives may be contained.

(Crystal melting heat)
The heat of crystal fusion of the thermoplastic resin composition (A) is not limited. Among them, 40 g / J or less is preferable, 35 g / J or less is more preferable, 30 g / J or less is more preferable, and 25 g / J or less is particularly preferable. Moreover, it is preferable that it is 10 g / J or more.
If the heat of crystal fusion of the thermoplastic resin composition (A) falls within this range, the porosity of the reflective material and the shape of the pores tend to be appropriate, and the shrinkage ratio also tends to be appropriate.

  The “crystal melting heat amount” is about 10 mg of sample heated from −40 ° C. to 200 ° C. at a heating rate of 10 ° C./min according to JIS K 7122 using a differential scanning calorimeter, and it is 5 minutes at 200 ° C. After holding, the temperature is lowered to −40 ° C. at a cooling rate of 10 ° C./min, and the temperature can be determined again from the thermogram measured when the temperature is raised to 200 ° C. at a heating rate of 10 ° C./min.

<Method of manufacturing the present reflector>
An example of a method of manufacturing the present reflector will be shown below. However, it is not limited to the following manufacturing method, and a publicly known method can be adopted.

First, a thermoplastic resin composition (A) is prepared by blending a polypropylene resin (a1), a low elastic modulus olefin resin (a2), a filler, and other additives used as needed. Specifically, these raw materials are mixed with a ribbon blender, tumbler, Henschel mixer, etc., and then, using a Banbury mixer, a single-screw or twin-screw extruder, etc., a temperature (for example, 190.degree. C. to 250.degree. The compound of the thermoplastic resin composition (A) is obtained by kneading at で C).
Alternatively, the thermoplastic resin composition (A) can also be obtained by adding predetermined amounts of the polypropylene resin (a1), the low elastic modulus olefin resin (a2), the filler, and the like using separate feeders. In addition, a masterbatch is prepared in which a filler, other additives, and the like are mixed in advance into a polypropylene resin (a1) and / or a low elastic modulus olefin resin (a2) to a high concentration, and this masterbatch and the polypropylene resin (A1) and / or a low elastic modulus olefin resin (a2) may be mixed to form a thermoplastic resin composition (A) having a desired filler concentration.

Next, after drying the thermoplastic resin composition (A) obtained in this way, it supplies to an extruder and it is made to heat and fuse | melt above predetermined temperature. The conditions such as the extrusion temperature are optional, but preferably 190 to 270 ° C., for example.
Thereafter, the thermoplastic resin composition (A) in a molten state is extruded from the slit-shaped discharge port of the single-layer T-die, and solidified on a cooling roll to form a cast sheet.

The obtained cast sheet is stretched at least uniaxially. By stretching, the interface between the polypropylene resin (a1) and the filler in the thermoplastic resin composition (A) can be peeled off to form pores. Furthermore, it is particularly preferred that the cast sheet be biaxially stretched. Biaxial stretching is preferable because formation of pores can further proceed and the porosity can be controlled within an appropriate range.
In addition, when biaxially stretched, the anisotropy of the laminated reflective material to be obtained becomes small, the anisotropy of physical properties can be made small, and the mechanical strength can also be increased.

Although the stretching temperature at the time of stretching the cast sheet is not limited, it is preferably equal to or less than the melting point (Tm) of the polypropylene resin (a1), specifically 170 ° C. or less, and preferably (Tm-20 ° C.) or less Is more preferred. Moreover, (Tm-70 ° C) or more is preferred, and (Tm-50 ° C) or more is more preferred.
If the stretching temperature is below the above upper limit, the stretching orientation becomes high, and as a result, the formation of pores becomes easy, which is preferable, and the film softened during roll stretching adheres to the roll surface and is processed It is preferable because it is unlikely to cause the problem of
If the stretching temperature is at least the above lower limit, film formation can be stably performed without breakage of the film at the time of stretching, and it is preferable to use it under a high temperature environment (about 90 to 100 ° C.) generated practically. In the above, it is preferable because there is little possibility of causing problems such as changes in the dimensions of the film (heat shrinkage).

The stretching order in biaxial stretching is not particularly limited, and may be, for example, simultaneous biaxial stretching or sequential stretching. After forming a cast sheet in a molten state, the sheet may be drawn in the machine direction (MD) by roll drawing and then drawn in the transverse direction (TD) by tenter drawing or biaxial drawing by tubular drawing or the like. Good.
At this time, the stretching ratio is not limited. Among them, the area magnification is usually 4 times or more, preferably 5 times or more, more preferably 6 times or more, and the upper limit is usually 25 times or less, preferably 20 times or less, more preferably 15 times or less. By setting the area magnification within the above range, the porosity of the reflective material can be controlled to an appropriate range, and excellent reflection performance and hiding performance can be exhibited, which is preferable.
When sequential biaxial stretching is performed, the stretching ratio of the first axis is preferably 1.1 to 5.0 times, more preferably 1.5 to 3.5 times, and the stretching ratio of the second axis is Preferably it is 1.1 to 5.0 times, more preferably 2.5 to 4.5 times.

  After stretching, in order to impart dimensional stability (shape stability of voids) to the laminated film, heat setting is preferably performed. Under the present circumstances, it is preferable that the processing temperature for heat-setting a film is 130-160 degreeC. The processing time required for heat fixation is preferably 1 second to 3 minutes.

In the present reflector, “other layers” are laminated on one or both surfaces or both surfaces of the layer formed of the thermoplastic resin composition (A) as long as the function of the layer formed of the thermoplastic resin composition (A) is not impaired. Can also be a multi-layered structure.
At this time, the number of layers in other layers is not limited. The other layers may be one, two or three or more layers. When it is a structure of three or more layers especially, it is preferable to make the layer which consists of a thermoplastic resin composition (A) into an intermediate | middle layer.
Moreover, the material which comprises another layer is arbitrary. Among them, a thermoplastic resin or a thermoplastic resin composition is preferable, and an adhesive layer or the like may be used. Among them, as described later, it is preferable to laminate a layer made of the thermoplastic resin composition (B).
Moreover, the other layer may form a porous structure by containing a filler like layer A.

[This laminated reflector]
Next, among the present reflectors, a layer formed of the thermoplastic resin composition (B) was laminated on one side or both sides of the layer formed of the thermoplastic resin composition (A). The reflective material (it is also called "this lamination reflective material") which consists of an extending | stretching sheet is demonstrated.

  By providing the layer made of the thermoplastic resin composition (B), it is possible to further improve the heat resistance and the mechanical strength of the present reflecting material having the characteristics such as excellent reflection performance, hiding performance, and lightness (low specific gravity). Since the filler can be added and the falling of the filler from the reflective material can be prevented, the performance can be further improved.

  The present laminated reflective material is provided with a layer (referred to as "layer A") composed of the thermoplastic resin composition (A) and a layer (referred to as "layer B") composed of the thermoplastic resin composition (B), Other layers other than these may be provided, and the number of layers in the other layers is not limited. The other layers may be one, two or three or more layers. When it is a structure of three or more layers especially, it is preferable to make the layer which consists of a thermoplastic resin composition (A) into an intermediate | middle layer.

The following lamination structure can be mentioned as a preferable lamination structure of this lamination reflective material.
Two-layer configuration of layer A and layer B, three-layer configuration with layer A as center layer and layer B as both surface layers, layer A as center layer, layer B as one surface layer, other layers as other surface layer Further, there may be mentioned a configuration having an adhesive layer between layers in any of these configurations, and the like.
At this time, the layer B and the other layers may form a porous structure by containing a filler in the same manner as the layer A.

<Thermoplastic resin composition (B)>
The thermoplastic resin contained in the thermoplastic resin composition (B) is not limited. Among them, an amorphous resin having a glass transition temperature (JIS K 7121) of 90 to 150 ° C. is preferably used.
By using an amorphous resin having a glass transition temperature of 90 to 150 ° C., heat resistance can be imparted to the present laminated reflector, which is preferable.
The term "amorphous resin" as used herein refers to a resin in which the exothermic peak associated with crystallization is not observed or the amount of heat of crystal fusion is 10 J / g or less even if observed.
In addition, “amorphous resin” exhibits stable characteristics below the glass transition temperature even if the environmental temperature changes, and it has a small shrinkage rate and excellent dimensional stability up to the temperature near the glass transition temperature, High heat resistance can be imparted to the present laminated reflector.
Therefore, if the glass transition temperature of the resin constituting the layer B is in the above-mentioned range, the heat resistance is preferably improved even when used as a component of a liquid crystal display or the like.

From this point of view, the glass transition temperature of the thermoplastic resin contained in the thermoplastic resin composition (B) is preferably 90 to 150 ° C., more preferably 100 to 150 ° C., and particularly preferably 110 to 150 ° C. More preferable.
If a glass transition temperature is below the said upper limit, extending | stretching temperature will not become high too much, vacancy formation of the layer which has a thermoplastic resin (A) as a main component will become easy, and is preferable. Moreover, if it is more than the said lower limit, it will be easy to make small the shrinkage | contraction rate in the high temperature environment which generate | occur | produces practically, and it is excellent in dimensional stability, and preferable.

  Examples of such non-crystalline resin include cycloolefin resin (b1), polystyrene, polycarbonate, acrylic resin, non-crystalline polyester resin, polyether imide, thermoplastic polyimide and the like. Among them, in consideration of stretchability, glass transition temperature and transparency, cycloolefin resins (b1), polystyrene and polycarbonate resins are preferable, and among them, adhesion to a layer containing the thermoplastic resin composition (A) as a main component From the viewpoint of the properties, cycloolefin resins (b1) are particularly preferred.

(Cycloolefin resin (b1))
The cycloolefin resin (b1) includes both cycloolefin homopolymers and cycloolefin copolymers.
The cycloolefin resin is an addition (co) polymer of cycloolefin or a hydrogenated product thereof (I), an addition copolymer of cycloolefin and α-olefin or a hydrogenated product thereof (2), ring opening of cycloolefin ( It is classified into co-polymers or their hydrogenated products (3).

  Specific examples of cycloolefins include cyclopentene, cyclohexene, cyclooctene; single ring cycloolefins such as cyclopentadiene and 1,3-cyclohexadiene; bicyclo [2.2.1] hept-2-ene (common name: norbornene) 5-methyl-bicyclo [2.2.1] hept-2-ene, 5,5-dimethyl-bicyclo [2.2.1] hept-2-ene, 5-ethyl-bicyclo [2.2.1 Hept-2-ene, 5-butyl-bicyclo [2.2.1] hept-2-ene, 5-ethylidene-bicyclo [2.2.1] hept-2-ene, 5-hexyl-bicyclo [2] .2.1] Hept-2-ene, 5-octyl-bicyclo [2.2.1] hept-2-ene, 5-octadecyl-bicyclo [2.2.1] hept-2-ene, 5-methylide -Bicyclo [2.2.1] hept-2-ene, 5-vinyl-bicyclo [2.2.1] hept-2-ene, 5-propenyl-bicyclo [2.2.1] hept-2-ene Etc. 2 ring cycloolefins such as

Tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene (common name: dicyclopentadiene), tricyclo [4.3.0.1 ^2,5 ] deca-3-ene; tricyclo [4. 4.4.0.1 ^2,5 ] undeca-3,7-diene or tricyclo [4.4.0.1 ^2,5 ] undeca-3,8-diene or partial hydrogenation products thereof (or cyclopentadiene) is an adduct of cyclohexene) tricyclo [4.4.0.1 ^{2, 5]} undec-3-ene; 5- cyclopentyl - bicyclo [2.2.1] hept-2-ene, 5-cyclohexyl - bicyclo [2.2.1] Hept-2-ene, 5-cyclohexenylbicyclo [2.2.1] hept-2-ene, 5-phenyl-bicyclo [2.2.1] hept-2-ene Ring cycloolefin;

Tetracyclo [4.4.0.1 ^2,5 . ^{17 10} ] dodec-3-ene (also simply referred to as tetracyclododecene), 8-methyltetracyclo [4.4.0.1 ^2,5 . 17 ¹⁰ ] dodec-3-ene, 8-ethyltetracyclo [4.4.0.1 ^2,5 . 17 ¹⁰ ] dodec-3-ene, 8-methylidenetetracyclo [4.4.0.1 ^2,5 . 17 ¹⁰ ] dodec-3-ene, 8-ethylidenetetracyclo [4.4.0.1 ^2,5 . 17 ¹⁰ ] dodec-3-ene, 8-vinyltetracyclo [4, 4. 0.1 ^{2, 5} . 17 ¹⁰ ] dodec-3-ene, 8-propenyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ! Four-ring cycloolefin such as dodec-3-ene;

8-cyclopentyl-tetracyclo [4.4.0.1 ^2,5 . 17 ¹⁰ ] dodec-3-ene, 8-cyclohexyl-tetracyclo [4.4.0.1 ^2,5 . 17 ¹⁰ ] dodec-3-ene, 8-cyclohexenyl-tetracyclo [4.4.0.1 ^2,5 . 17 ¹⁰ ] dodec-3-ene, 8-phenyl-cyclopentyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^{7, 10} ] dodec-3-ene; tetracyclo [7.4.1 ^{3, 6} . 0 ^1,9 . 0 ^2,7 ] tetradeca-4,9,11,13-tetraene (also referred to as 1,4-methano-1,4,4a, 9a-tetrahydrofluorene), tetracyclo [8.4.1 ^4,7 . 0 ^{1, 10} . 0 ^3,8 ] pentadeca-5,10,12,14-tetraene (also referred to as 1,4-methano-1,4,4a, 5,10,10a-hexahydroanthracene); pentacyclo [6.6.1] .1 ^{3, 6} . 0 ^{2, 7} . 0 ^9,14 ] -4-hexadecene, pentacyclo [6.5.1.1 ^3,6 . 0 ^{2, 7} . 0 ^{9, 13} ] -4-pentadecene, pentacyclo [7.4.0.0 ^2,7 . 1 ^3,6 . 110, ¹³ ] -4-pentadecene; heptacyclo [8.7.0.1 ^2,9 . 1 ^{4, 7} . 1 ^{11, 17} . 0 ^{3, 8} . 0 ^{12, 16} ] -5-Eicosene, heptacyclo [8.7. 0.1 ^{2, 9} . 0 ^{3, 8} . 1 ^{4, 7} . 0 ^{12, 17} . 1, ^{13 16} ! ^-14-eicosene ; and polycyclic cycloolefins such as tetramer of cyclopentadiene.
These cycloolefins can be used alone or in combination of two or more as a copolymer.

  Specific examples of α-olefins copolymerizable with cycloolefins include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3 -Ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-pentene Hexane, 3-ethyl-1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, etc. Carbon number 2 to 20, preferably carbon number 2-8 ethylene or alpha-olefin etc. are mentioned. These α-olefins can be used alone or in combination of two or more.

  There is no particular limitation on the polymerization method of cycloolefin or cycloolefin and α-olefin and the hydrogenation method of the obtained polymer, and it can be carried out according to known methods.

  Examples of commercially available cycloolefin resins include “Zeonor” manufactured by Nippon Zeon Co., Ltd. (hydrogenated product of ring-opened polymer of cyclic olefin), “Aper” manufactured by Mitsui Chemicals, Inc. (addition co-polymerization of ethylene and tetracyclododecene) Polymer), "TOPAS" (addition copolymer of ethylene and norbornene) manufactured by Nippon Polyplastics Co., Ltd., and the like can be used. Among them, “Zeonor” and “TOPAS” are preferable because they have a low light absorption action and a layer containing a thermoplastic resin composition (B) containing them as a main component does not impair the reflection performance.

The glass transition temperature (Tg) of the cycloolefin resin (b1) is not limited. The temperature is preferably 100 ° C. or more and 160 ° C. or less, in particular 110 ° C. or more or 150 ° C. or less, and more preferably 120 ° C. or more or 140 ° C. or less.
In addition, glass transition temperature (Tg) can also be adjusted to the said range by using together 2 or more types of cycloolefin resin from which glass transition temperature (Tg) differs. Here, the glass transition temperature (Tg) is a value measured according to JIS K7210.

The melt flow rate (MFR) of the cycloolefin resin (b1) is not particularly limited. Among them, 0.5 to 25 g / 10 min is preferable, and 1.0 to 15 g / 10 min is more preferable.
If the MFR of the cycloolefin resin (b1) is equal to or more than the lower limit value, the melt viscosity of the resin at the time of molding is high, and sufficient productivity tends to be ensured. On the other hand, when the MFR is equal to or less than the upper limit value, the mechanical strength of the obtained reflector can be sufficiently maintained.
MFR is a value measured under the conditions of a temperature of 230 ° C. and a load of 2.16 kgf (21.18 N) according to JIS K7210.

The content of the cycloolefin resin (b1) is not limited. It is preferable that it is 50 mass% or more of the whole mass of a thermoplastic resin composition (B), More preferably, it is 55 mass% or more, More preferably, it is 60 mass% or more. If content of a cycloolefin type-resin (b1) is more than the said lower limit, since it becomes possible to provide heat resistance to a lamination | stacking reflection material, it is preferable.
Moreover, the upper limit of content of cycloolefin type-resin (b1) is not limited, 100 mass% may be sufficient with respect to the whole mass of a thermoplastic resin composition (B). When it is possible to impart and modify the fracture resistance and bending resistance of the laminated reflective material by using other resins in combination, it is preferably 90% by mass or less, more preferably 85% by mass or less, and further preferably Is 80 mass% or less.

  As mentioned above, when thermoplastic resin composition (B) uses cycloolefin resin (b1) and other resin together, other resin is not limited. Preferably, an olefin resin (b2) excluding a cycloolefin resin and / or a thermoplastic elastomer (b3) is preferably contained. By containing the olefin resin (b2) excluding the cycloolefin resin and / or the thermoplastic elastomer (b3) in the thermoplastic resin composition (B), the fracture resistance of the present laminated reflective material tends to be improved. is there.

  The olefin resin (b2) excluding the cycloolefin resin may be any olefin resin other than the cycloolefin resin (b1). Preferably, a polypropylene resin (a1) or a low elastic modulus olefin resin (a2) is preferable from the viewpoint of improving the interfacial adhesion with the layer containing the thermoplastic resin composition (A) as the main component.

In addition, the olefin resin (b2) excluding the cycloolefin resin may have β crystal activity, and by containing the above β crystal nucleating agent in the thermoplastic resin composition (B), β crystal may be obtained. It may have activity.
When the layer containing the thermoplastic resin composition (B) as the main component contains the β crystal nucleating agent, the content is equivalent to the content in the layer containing the thermoplastic resin composition (A) as the main component May also be different. When the layer containing the thermoplastic resin composition (B) as the main component contains the β crystal nucleating agent, not only the layer containing the thermoplastic resin composition (A) as the main component, but also the thermoplastic resin composition (B) The layer having as a main component) can also have a porous structure.

(Thermoplastic elastomer (b3))
Examples of the thermoplastic elastomer (b3) to be contained in the thermoplastic resin composition (B) include olefinic thermoplastic elastomers, styrene thermoplastic elastomers, urethane thermoplastic elastomers, polyester thermoplastic elastomers, etc. These can be used alone or in combination of two or more.
Among them, an olefin-based thermoplastic elastomer or a styrene-based thermoplastic elastomer is preferable because it has a high affinity to the cycloolefin resin (b1), and the effect of improving the fracture resistance of the reflective material is high. Furthermore, since the olefin-based thermoplastic elastomer or the styrene-based thermoplastic elastomer has high affinity with the polypropylene-based resin (a1) contained in the thermoplastic resin composition (A), the thermoplastic resin composition (A) is mainly used. There is a tendency that the interfacial adhesion with the component layer can be improved.

The olefin-based thermoplastic elastomer is not limited in its type. For example, a copolymer of at least two olefins selected from the group consisting of polypropylene and finely dispersed ethylene-propylene rubber, etc., and ethylene and an α-olefin having 3 to 20 carbon atoms (hereinafter referred to as It may be referred to as "copolymerized olefin-based thermoplastic elastomer".
Although a C3-C20 alpha-olefin is not limited, Specifically, a chain olefin is mentioned. Examples of chained olefins include linear olefins and branched olefins.
The olefin-based thermoplastic elastomer contained in the thermoplastic resin composition (B) does not include the cycloolefin-based resin (b1) and the olefin-based resin (b2) excluding the cycloolefin-based resin.

Examples of linear olefins include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene and the like can be mentioned.
On the other hand, as branched olefins, for example, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-ethyl-1-hexene, 2,2,4-trimethyl-1 -Pentene etc. can be mentioned.

  Examples of combinations of starting monomers for copolymerized olefin elastomers include ethylene / propylene, ethylene / 1-butene, ethylene / 1-hexene, ethylene / 1-octene, ethylene / 4-methyl-1-pentene, ethylene / propylene / 1-butene, ethylene / propylene / 1-hexene, ethylene / 1-butene / 1-hexene, propylene / 1-butene, propylene / 1-hexene, propylene / 1-octene, propylene / 4-methyl-1-pentene, Propylene / 1-butene / 1-hexene etc. can be mentioned.

When the copolymerized olefin-based elastomer is a copolymer of two types of monomers, the total number of carbon atoms of the two types of monomers is preferably 6 or more.
Moreover, as a copolymerized olefin type elastomer, the copolymer by the combination of a propylene and a C4-C20 alpha-olefin is also preferable. Specifically, propylene / 1-butene copolymer, propylene / 1-hexene copolymer, propylene / 1-octene copolymer, propylene / 4-methyl-1-pentene copolymer, propylene / 1-butene / 1-hexene copolymer is preferable.
The copolymerized olefin-based elastomers of these preferred embodiments have high affinity with the polypropylene resin (a1) contained in the thermoplastic resin composition (A), and thus the thermoplastic resin composition (A) is mainly contained. There is a tendency for the interface adhesion with the layer to be improved to be improved.

  As olefin-based thermoplastic elastomers, "Thermo-Lan", "Zeras", Mitsubishi Chemical's "Milastomer", "Toughmer", "Notio", Sumitomo Chemical's "Espolex", "Tuff Selenium", Sun Aromaro It can be appropriately selected and used from commercially available products such as "Adflex" and "Adsil", manufactured by Dow Chemical Co., "Versify", "Infuse", and "Engage" manufactured by Dow Chemical Company.

As a styrene-type thermoplastic elastomer, the copolymer of conjugated dienes, such as styrene and butadiene or isoprene, the hydrogenated substance etc. can be mentioned, for example. Specifically, hydrogenated styrene butadiene elastomer (HSBR), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene butylene-styrene block copolymer And coalesced (SEBS), styrene-ethylene propylene-styrene block copolymer (SEPS).
Among them, hydrogenated styrene butadiene elastomer (HSBR) and styrene-ethylene butylene-styrene block copolymer (SEBS) have high affinity with the cycloolefin resin (b1), so the fracture resistance of the reflective material is improved. It is preferable because it is highly effective. Furthermore, since the affinity with the polypropylene resin (a1) contained in the thermoplastic resin composition (A) is high, the interfacial adhesion with the layer containing the thermoplastic resin composition (A) as the main component can be secured. preferable.

  As the styrene-based thermoplastic elastomer, commercially available products such as "Lavaron" manufactured by Mitsubishi Chemical Co., Ltd., "Tuftec" manufactured by Asahi Kasei Corp., "Tafprene" manufactured by Asahi Chemical Co., "Dynalon" manufactured by JSR, "Septon" manufactured by Kuraray can be used. .

(Other ingredients)
The thermoplastic resin composition (B) may contain a resin other than the above and other components. For example, it contains fillers, antioxidants, light stabilizers, heat stabilizers, dispersants, UV absorbers, fluorescent brighteners, compatibilizers, lubricants, beta crystal nucleating agents, alpha crystal nucleating agents, and other additives. You may

<Manufacturing method of this laminated reflector>
In the present laminated reflective material, the method of forming other layers other than the layer A is not limited, and various methods such as coating, coextrusion, extrusion lamination, heat fusion, bonding with an adhesive can be adopted. . It is preferable to use the co-extrusion method particularly when the layer B is provided as another layer.

  Below, as an example of a manufacturing method of this lamination reflective material, the lamination reflective material of 3 layer composition which makes layer A the center layer, and makes layer B both surface layers is explained. However, the method of producing the laminated reflective material is not limited to the following method.

First, a thermoplastic resin composition (A) is prepared by blending a polypropylene resin (a1), a low elastic modulus olefin resin (a2), a filler, and other additives used as needed. Specifically, these raw materials are mixed with a ribbon blender, tumbler, Henschel mixer, etc., and then, using a Banbury mixer, a single-screw or twin-screw extruder, etc., a temperature (for example, 190.degree. C. to 250.degree. The compound of the thermoplastic resin composition (A) is obtained by kneading at で C).
Alternatively, the thermoplastic resin composition (A) can also be obtained by adding predetermined amounts of the polypropylene resin (a1), the low elastic modulus olefin resin (a2), the filler, and the like using separate feeders. In addition, a masterbatch is prepared in which a filler, other additives, and the like are mixed in advance into a polypropylene resin (a1) and / or a low elastic modulus olefin resin (a2) to a high concentration, and this masterbatch and the polypropylene resin (A1) and / or a low elastic modulus olefin resin (a2) may be mixed to form a thermoplastic resin composition (A) having a desired filler concentration.

On the other hand, a thermoplastic resin composition containing a cycloolefin resin (b1), an olefin resin (b2) excluding a cycloolefin resin and / or a thermoplastic elastomer (b3), and other additives used as needed Prepare an object (B). Specifically, an olefin resin (b2) other than a cycloolefin resin and / or a thermoplastic elastomer (b3), other additives, etc. may be added to the cycloolefin resin (b1) as required, to thereby prepare a ribbon blender. Heat with mixing with a tumbler, Henschel mixer, etc., using a Banbury mixer, single-screw or twin-screw extruder, etc., at a temperature (for example, 220.degree. C. to 270.degree. C.) higher than the flow start temperature of the resin. A compound of the plastic resin composition (B) is obtained.
Alternatively, as in the case of the thermoplastic resin composition (A), each raw material may be added in a predetermined amount by a separate feeder, or a part of the raw material may be used as a master batch.

Next, the thermoplastic resin composition (A) and the thermoplastic resin composition (B) thus obtained are dried and then supplied to different extruders, respectively, and heated to a predetermined temperature or higher. And let it melt. Although conditions such as extrusion temperature are optional, for example, the extrusion temperature of the thermoplastic resin composition (A) is preferably 190 to 270 ° C., and the extrusion temperature of the thermoplastic resin composition (B) is preferably 220 to 270 ° C. .
Thereafter, the molten thermoplastic resin composition (A) and the thermoplastic resin composition (B) are joined to a T-die for two types and three layers, and extruded in a laminated form from the slit-like discharge port of the T die The roll is closely solidified to form a cast sheet.

The obtained cast sheet is then stretched, but the stretching step is the same as the above-mentioned method of manufacturing the present reflector.
In addition, it is preferable that the extending | stretching temperature at the time of extending | stretching a cast sheet is the range more than the glass transition temperature (Tg) of cycloolefin resin (b1) and (Tg + 50 degreeC). When the stretching temperature is equal to or higher than the glass transition temperature (Tg), film formation can be stably performed without breakage of the film at the time of stretching. Further, if the stretching temperature is a temperature of (Tg + 50) ° C or less, the stretching orientation becomes high, and as a result, the formation of pores becomes easy, which is preferable.

<Various characteristics of main reflector and main laminate reflector>
In the following description of various characteristics, the present reflector includes the present laminated reflector, unless otherwise specified.

(Thickness)
The thickness of the present reflector is not particularly limited. From the viewpoint of handling in practical use, it is preferably 30 to 500 μm, and more preferably 50 μm or more or 300 μm or less.
In addition, since the present reflector has a uniform porous structure and the porosity is controlled to an appropriate range, the reflection performance and the hiding performance are particularly excellent. The excellent performance is particularly advantageous in the case of thin wall, so the thickness of the present reflector is more preferably 50 to 150 μm, in particular 60 μm or more or 100 μm or less. The present reflector has excellent reflection performance even in the case of such a thin wall, so it is also suitable for a reflector for small liquid crystal displays such as smartphones and tablet terminals that are required to be thinner and lighter. It can be used.

Although the thickness of the layer mainly composed of the thermoplastic resin composition (A) in the present laminated reflector is not limited, it is preferably 10% or more, more preferably 20% or more, based on the thickness of the laminated reflector. It is preferably 30% or more, particularly preferably 50% or more, preferably 95% or less, more preferably 90% or less.
If the thickness of the layer containing the thermoplastic resin composition (A) as the main component is not less than the above lower limit value, in addition to excellent lightness and flexibility, there is a tendency to be able to secure excellent reflection performance and concealment performance. In addition, when the thickness of the layer containing the thermoplastic resin composition (A) as the main component is equal to or less than the above upper limit, the heat resistance of the laminated reflective material tends to be secured.

(Porous structure)
The present reflector has a uniform porous structure even when the filler is contained at a high concentration. This is due to the action of the low elastic modulus olefin resin (a2) contained in the reflector. That is, in the present reflector, the low elastic modulus olefin resin (a2) makes the thermoplastic resin composition (A) ductile, and when it is stretched, it tends to locally adhere particularly to the interface with the filler. The thermoplastic resin composition (A) while impact-absorbing the stress and mechanical stress which tends to be locally applied to the β-crystal part when the polypropylene resin (a1) forms the β-crystal It plays the role of uniform diffusion throughout. As a result, it is considered that a uniform porous structure is formed in the reflective material, and the formation of excessive pores is suppressed, and the porosity is controlled to an appropriate range. At the same time, in particular, it is suppressed that local pore formation excessively progresses, that is, that excessive extension is only applied to the locally formed pores, and as a result, the partition between the pores is broken. It is thought that a porous structure in which the independent state of pores is maintained without being formed.

(Porosity)
Although the porosity of the present reflector is not limited, it is preferably 50% or more and 70% or less, and more preferably 55% or more or 65% or less.
If the porosity of the present reflector is not less than the lower limit value, it is preferable because excellent reflection performance can be secured in addition to lightness (low specific gravity). In addition, when the porosity of the reflective material is equal to or less than the above upper limit, the porous structure of the reflective material is uniform and formation of excessive pores is suppressed, mechanical strength of the reflective material is secured, and particularly light transmittance It is preferable because it can be suppressed to ensure excellent concealing performance.

The porosity of the present reflector can be determined by the following equation.
Porosity (%) = {(density of sheet before stretching−density of film after stretching) / density of sheet before stretching} × 100
In the above equation, "density of the film after stretching" is replaced with "density of the reflective material", and "density of the sheet before stretching" is replaced with "actual density after melting, defoaming and solidifying the reflective material" be able to.
Moreover, the value of the porosity in the present laminated reflector may be treated as an averaged value of the entire laminated reflector, or only the layer mainly composed of the thermoplastic resin composition (A) may be targeted. . When the other layers have substantially no pores, it is preferable that the layer containing the thermoplastic resin composition (A) as the main component has the above-mentioned porosity.

(Reflective performance, concealment performance)
Since the present reflector has a uniform porous structure and the porosity is controlled to an appropriate range, it can have high reflection performance and hiding performance over the entire visible light region.
For this reason, in the present reflector, the average reflectance on at least one side is preferably 97% or more to light having a wavelength of 450 to 750 nm, and more preferably 98% or more.
Also, in general, the reflectance of the reflective material tends to decrease as the wavelength of light is on the higher wavelength side. In the present reflector, for example, the reflectance for light with a wavelength of 750 nm is preferably 95% or more, and more preferably 96% or more.

  Moreover, it is preferable that this reflector is 4% or less with respect to the light of wavelength 450nm-750 nm of the average transmittance | permeability of at least single side | surface. The present reflector has excellent concealing performance even in the case of a thin wall of 150 μm or less, and thus is suitable for a reflective material for small liquid crystal displays such as smartphones and tablet terminals, which are required to be thin and lightweight.

(Break resistance and flex resistance)
The fracture resistance of this reflector can be measured by the Elmendorf tear method described in JIS K7128-2. If this value is 0.1 N or more, there is little possibility of breakage when handling the reflective material, which is preferable.
Moreover, the bending resistance of this reflector can be measured by the cylindrical mandrel method etc. of JISK5600-5-1. If this value is 10 mm or less, there is little possibility of breakage or marking when handling the reflective material, which is preferable.

<Use>
The present reflecting material and the present laminated reflecting material can be used in various applications such as industrial material applications, packaging material applications, optical material applications, electric material applications and the like because of excellent mechanical properties, heat resistance and optical properties.
Specifically, in addition to the properties as a polyolefin film, because of its light weight (low specific gravity), it can be used as a separator for batteries or electrolytic capacitors, various separation films, clothing, waterproof films for medical applications, thermosensitive transfer recording sheets, etc. It can be used for a wide range of applications. Among them, it is suitable for a reflective material such as a liquid crystal display, a lighting fixture, or a lighting signboard since it has a uniform porous structure and controlled porosity in an appropriate range, and is particularly excellent in reflection performance and hiding performance. It can be used for

The present reflector and the present laminated reflector can be used as the reflector as they are, but can also be used by laminating on a metal plate or a resin plate. For example, a liquid crystal display device such as a liquid crystal display, a lighting apparatus , It is useful as a reflector used for a lighting signboard etc. As a metal plate, an aluminum plate, a stainless steel plate, a galvanized steel plate etc. can be mentioned, for example.
The method of laminating the present reflector or the present laminated reflector on a metal plate or a resin plate is not limited, for example, a method of using an adhesive, a method of heat fusion, a method of bonding via an adhesive sheet, extrusion coating A method etc. can be mentioned.

  As an adhesive for bonding the metal plate or the resin plate to the main reflector or the multilayer reflector, an adhesive such as polyester, polyurethane or epoxy can be used. In this method, using a generally used coating equipment such as a reverse roll coater or a kiss roll coater, adhesion after drying is performed on the surface of a metal plate or resin plate to which the present reflector or the present laminated reflector is bonded. The adhesive is applied so that the agent film thickness is about 2 to 4 μm. Next, the coated surface is dried and heated by an infrared heater and / or a hot air heating furnace or the like, and the present reflection material or the present lamination reflection material is covered and cooled using a roll laminator or the like to obtain a reflection plate.

<Explanation of terms>
In the present invention, the term "film" refers to "sheet", and the term "sheet" also includes "film".
Moreover, when expressing as "X-Y" in this invention, the meaning of "preferably larger than X" and "preferably smaller than Y" is included with the meaning of "X or more and Y or less" unless otherwise stated. Further, the same applies to the case of expressing “X or more” and “Y or less”.
In the present invention, “reflection” means, unless otherwise stated, reflection of light, and more specifically, reflection of visible light. Further, in the present invention, “hiding” means, unless otherwise stated, light shielding property, and more specifically means light shielding property for visible light.

  Hereinafter, the present invention will be more specifically described by way of examples. However, the present invention is not limited to these, and various applications are possible without departing from the technical concept of the present invention.

<Measurement and evaluation method>
The measuring method and evaluation method of the sample obtained by Example and a comparative example are demonstrated below. Hereinafter, the take-up (flow) direction at the time of film formation is indicated as MD, and the orthogonal direction is indicated as TD.

[Porosity]
The density of the film before stretching (unstretched film density) and the density of the film after stretching (stretched film density) were measured, and the porosity (%) of the film was determined by the following equation.
Porosity (%) = {(unstretched film density−stretched film density) / unstretched film density} × 100

[Pore structure]
The cross section of the film was observed by a scanning electron microscope (SEM), and the state of "uniformity" and "vacancy maintenance" of the porous structure of the film was evaluated based on the following criteria. "○" is a practical level.
In addition, observation of the uniaxially stretched film was made into the surface (side view) parallel to MD, and observation of the biaxially stretched film was made into the surface (end view) parallel to TD.

"Pore structure uniformity"
X (very poor): In the film cross section after biaxial stretching, a stretched region, a non-stretched region, and a stretched region are observed in order along the stretching direction.
Δ (poor): In the cross section of the film after uniaxial stretching, stretched regions, non-stretched regions, and stretched regions are observed along the stretching direction, but their identification becomes difficult after biaxial stretching.
Good (good): Even in any film cross section after biaxial stretching after uniaxial stretching, it is difficult to distinguish between the stretched region and the non-stretched region, and has a uniform porous structure.

"Pore structure maintainability"
X (poor): The partition walls of the pores are broken and the pores are in communication with each other.
○ (good): The holes are maintained in an independent state.

[Reflection performance]
The integrating sphere is attached to a spectrophotometer ("U-3900H" manufactured by Hitachi, Ltd.), and the reflectance when the alumina white plate is 100% is measured at 0.5 nm intervals over wavelengths 340 nm to 800 nm, and wavelengths 450 nm and 550 nm. The reflectance for light of 650 nm and 750 nm was read. Moreover, the average value of the reflectance obtained over wavelength 450nm-750nm was calculated, and it was set as average reflectance (%).

[Hiding performance]
Attach an integrating sphere containing an alumina white plate to a spectrophotometer ("U-3900H" manufactured by Hitachi, Ltd.), and set the light transmittance to 100% of air (non-sample state) over a wavelength of 340 nm to 800 nm. The average value of the light transmittance measured over a wavelength of 450 nm to 750 nm was calculated at an interval of 5 nm, and defined as an average light transmittance (%). The lower the average light transmittance, the better the hiding power.

<Raw material>
The raw material used by the Example and the comparative example is demonstrated below. MFR is a value measured under the conditions of a temperature of 230 ° C. and a load of 2.16 kgf (21.18 N) according to JIS K7210.
HPP-1: Homopolypropylene resin "Novatec PP FY6 HA" (propylene homopolymer, MFR: 2.4 g / 10 min, tensile modulus: 1,800 MPa) manufactured by Japan Polypropylene Corporation
HPP-2: Homopolypropylene resin "Novatec PP FY4" (propylene homopolymer, MFR: 5 g / 10 min) manufactured by Japan Polypropylene Corporation

RPP-1: Propylene-based random copolymer "Sun Aroma PC741R" (Propylene / Ethylene random copolymer (ethylene: 7% by mass) manufactured by Sun Aroma Co., Ltd. MFR: 10 g / 10 min, tensile modulus: 500 MPa, melting point: 130 ° C.)
RPP-2: Propylene-based random copolymer "Sun Aroma PC 540 R" (Propylene / Ethylene random copolymer manufactured by Sun Aroma, MFR: 5 g / 10 min, tensile modulus: 500 MPa, melting point: 132 ° C.)
RPP-3: Propylene-based random copolymer "Prime Polypro F219DA" (Propylene / Ethylene random copolymer manufactured by Prime Polymer Co., Ltd. MFR: 8 g / 10 min, tensile modulus: 1,100 MPa)
BPP-1: Polypropylene based resin "Prime Polypro E-185G" (Propylene / Ethylene block copolymer, MFR: 0.3 g / 10 min) manufactured by Prime Polymer Co.

COP-1: Cycloolefin resin "TOPAS6013" (addition copolymer of ethylene and norbornene, MFR: 2 g / 10 min, glass transition temperature: 138 ° C) manufactured by Polyplastics
COP-2: Cycloolefin resin “TOPAS 7010” (addition copolymer of ethylene and norbornene, MFR: 11 g / 10 min, glass transition temperature: 110 ° C.) manufactured by Polyplastics

Titanium oxide: "KRONOS 2230" (rutile type titanium oxide manufactured by a chlorine method, manufactured by KRONOS Co., alumina, silica surface treatment, TiO ₂ content 96.0%, average particle diameter (D50): 0.37 μm)

Example 1
100 parts by mass of a mixture of HPP-1 and RPP-1 pellets and titanium oxide in a mass ratio of 15:15:70 to 0.05 parts by mass of β crystal nucleating agent (calcium pimelic acid) After melt-kneading using the twin-screw extruder heated at 240 degreeC, it pelletized and obtained the compound of a thermoplastic resin composition (A-1).
The compound is supplied to an extruder heated at 230 ° C. and melted, and then extruded through a T-die into a sheet shape, cooled and solidified on a cast roll heated to a surface temperature of 120 ° C., and an unstretched sheet body I got
The obtained sheet body was subjected to simultaneous biaxial stretching of 2 times in MD at 130 ° C. and 3 times in TD using a stretcher to obtain a reflective material with a thickness of 90 μm.
The porosity, the porous structure, the reflection performance, and the shielding performance were evaluated for the obtained reflector. In addition, about the porous structure, it evaluated also about the film after uniaxial stretching.

Example 2
100 parts by mass of a mixture of each pellet of COP-1, COP-2 and HPP-2 in a mass ratio of 23:52:25 to which 0.05 part by mass of β crystal nucleating agent (calcium pimelic acid) is added After melt-kneading using a twin-screw extruder heated to 240 ° C., the mixture was pelletized to obtain a compound of the thermoplastic resin composition (B-1).
The compound of the thermoplastic resin composition (A-1) prepared in Example 1 and the compound of the above thermoplastic resin composition (B-1) are respectively supplied to extruders A and B heated to 230 ° C. After melting, they are joined into a T-die for two types and three layers, and extruded in a sheet shape so as to have a three-layer structure of surface layer (B-1) / intermediate layer (A-1) / surface layer (B-1) It solidified by cooling on the cast roll, and was set as the non-stretching laminated sheet body.
The obtained laminated sheet body is roll stretched twice in MD at 125 ° C., and then biaxially stretched by tenter stretching in TD three times at 135 ° C. to obtain a thickness of 80 μm (surface layer: 10 μm each, middle) Layer: 60 μm) of a reflective material was obtained.
Evaluation similar to Example 1 was performed about the obtained sample. In addition, about the porosity of this sample, the porosity of the part of (A-1) layer is calculated by setting the porosity of (B-1) layer to 0%, and the porosity of the film (%) And

Example 3
100 parts by mass of a mixture of each pellet of HPP-1 and RPP-2 and titanium oxide in a mass ratio of 27:10:63 to which 0.05 part by mass of β crystal nucleating agent (calcium pimelic acid) is added, After melt-kneading using the twin-screw extruder heated at 240 degreeC, it pelletized and obtained the compound of a thermoplastic resin composition (A-2).
A thermoplastic resin composition (the same as in Example 2 except that pellets of BPP-1 were used instead of HPP-2 in the compound preparation of the thermoplastic resin composition (B-1) of Example 2) The compound of B-2) was obtained.
The point which used the thermoplastic resin composition (A-2) instead of the thermoplastic resin composition (A-1), and the thermoplastic resin composition (B-) instead of the thermoplastic resin composition (B-1) A reflector was prepared in the same manner as in Example 2 except that 2) was used, and the same evaluation as in Example 2 was performed.

Comparative Example 1
100 parts by mass of a mixture of HPP-1 pellets and titanium oxide mixed in a mass ratio of 30:70 to 0.05 parts by mass of β crystal nucleating agent (calcium pimelic acid) is heated to 240 ° C. After melt-kneading using a screw extruder, it pelletized and obtained the compound of the thermoplastic resin composition (A-3).
A reflector is prepared in the same manner as in Example 2 except that the thermoplastic resin composition (A-3) is used instead of the thermoplastic resin composition (A-1), and the same evaluation as in Example 2 is performed. The

Comparative Example 2
100 parts by mass of a mixture of HPP-1 and RPP-3 pellets and titanium oxide in a mass ratio of 20:17:63 to which 0.05 part by mass of β crystal nucleating agent (calcium pimelic acid) is added, After melt-kneading using a twin-screw extruder heated to 240 ° C., the mixture was pelletized to obtain a compound of a thermoplastic resin composition (A-4).
A reflector is prepared in the same manner as in Example 2 except that the thermoplastic resin composition (A-4) is used instead of the thermoplastic resin composition (A-1), and the same evaluation as in Example 2 is performed. The

Comparative Example 3
A laminated film is produced in the same manner as Comparative Example 1 except that the draw ratio of MD is 1.5 times and the draw ratio of TD is 2 times, and a reflective material with a thickness of 85 μm (surface layer: 10 μm each, intermediate layer: 65 μm) I got The porosity and the porous structure of the obtained sample were evaluated in the same manner as in Example 2. However, since no uniformity was observed in the porous structure, the evaluation of the reflection performance and the hiding performance was not performed.

Reference Example 1
The pellets of HPP-1 and titanium oxide are mixed at a mass ratio of 55:45, and then melt-kneaded using a twin-screw extruder heated to 230 ° C., and then pelletized to obtain a thermoplastic resin composition (A-6) ) Compound was obtained.
A reflector was prepared in the same manner as in Example 2 except that the thermoplastic resin composition (A-6) was used instead of the thermoplastic resin composition (A-1), and the same evaluation as in Example 2 was performed. The

Reference Example 2
A reflective material was prepared in the same manner as in Reference Example 1 except that the thickness was set to 100 μm (surface layer: 12 μm, intermediate layer: 76 μm), and the same evaluation as in Example 2 was performed.

From Table 2, the reflective material and the laminated reflective material of Examples 1 to 3 had a uniform porous structure even when the filler was contained at a high concentration, and the porosity was controlled to an appropriate range. Furthermore, since the average reflectance and the average light transmittance are also excellent, it is suitable as a reflector.
In Comparative Examples 1 and 2, the same stretching as in the example was performed using a thermoplastic resin composition not containing the low elastic modulus olefin resin (a2). As a result, the resulting laminated reflective material had pores formed excessively, and the uniformity of the porous structure and the state of maintaining the pores were not at a practical level. In addition, the average reflectance and the average light transmittance were also insufficient.
Although the porosity was controlled by lowering | hanging a draw ratio with respect to the comparative example 1 about the lamination | stacking reflective material of the comparative example 3, the state of the uniformity of a porous structure and the void | hole maintenance was not a practical level. This is considered to be due to the fact that the pores were broken by further stretching because the non-uniform porous structure was formed.
Reference Example 1 is a conventional product which has a low filler concentration and does not contain the low elastic modulus olefin resin (a2). The average reflectance is lower and the average transmittance is also higher than in the examples. In order to obtain reflection characteristics equivalent to those of the embodiment with this material, it is necessary to make the laminated reflective material thick (80 μm → 100 μm) as in Reference Example 2.

The reflector and the laminated reflector according to the present invention are reflectors having a uniform porous structure even if they contain a high concentration of filler, so it is easy to control the porosity to an appropriate range, and in particular, the reflector Excellent in performance and concealment performance. For this reason, it can be used suitably for reflective materials, such as a liquid crystal display, a lighting fixture, or a lighting signboard.
Further, in recent smart phone and tablet type image display devices, narrowing of an outer frame portion along with an increase in screen size and curving of an image display member are required. In response to such a requirement, when the reflective material is rigid, it is difficult to laminate it with other components to manufacture an image display device. The reflective material and the laminated reflective material of the present invention are more flexible (flexible) than conventional reflective materials, and thus can be suitably used as a reflective material particularly for use in a smartphone or tablet-type image display device.

Claims (10)

  A reflective material comprising a stretched sheet comprising a layer comprising a thermoplastic resin composition (A), wherein the thermoplastic resin composition (A) is a polypropylene resin (a1) and the modulus of elasticity is at least 100 MPa and at most 1050 MPa Reflective material containing an elastic modulus olefin resin (a2) and a filler.   The reflector according to claim 1, further comprising a layer comprising the thermoplastic resin composition (B) on at least one surface of the layer comprising the thermoplastic resin composition (A).   The reflector according to claim 1 or 2, wherein the filler is blended at a ratio of 50% by mass or more and 90% by mass or less with respect to the thermoplastic resin composition (A).   The low elastic modulus olefin resin (a2) is contained in an amount of 5 to 90% by mass based on the total amount of the polypropylene resin (a1) and the low elastic modulus olefin resin (a2). Reflective material.   The reflective material according to any one of claims 1 to 4, wherein the low elastic modulus olefin resin (a2) is a propylene random copolymer.   The reflective material according to any one of claims 1 to 5, which has a porosity of 50% to 70%.   The reflector according to claim 2, wherein the thermoplastic resin composition (B) contains a cycloolefin resin (b1).   The thermoplastic resin composition (B) contains a cycloolefin resin (b1) and an olefin resin (b2) excluding a cycloolefin resin and / or a thermoplastic elastomer (b3) according to claim 7. Reflective material.   The reflective material formed by laminating | stacking the reflective material in any one of Claims 1-8 on a metal plate or a resin board. A liquid crystal display, a lighting fixture or a lighting signboard comprising the reflective material according to any one of claims 1 to 9 as a component.