JP5696014B2 - Polyolefin resin composition and light diffusing sheet - Google Patents

Description

  The present invention relates to a polyolefin-based resin composition and a light-diffusing sheet, and more specifically, a polyolefin-based material that is lightweight, recyclable, has an excellent balance of light transmission and diffusibility, and is useful as a light-diffusing sheet material. The present invention relates to a resin composition and a light diffusing sheet comprising the same.

Conventionally, a resin composition using a polycarbonate resin, an acrylic resin, or the like as a main component has been used as a light diffusing film or sheet used for a cover or the like for protecting illumination. When used as a cover or the like for protecting illumination, it is required to efficiently diffuse the light in order to transmit the illumination light efficiently and at the same time brighten the room. For this reason, what uses polycarbonate resin and an acrylic resin for a continuous phase, and used other resin, a filler, etc. for a dispersed phase is reported (for example, patent documents 1-3).
In particular, Patent Document 3 reports that a polycarbonate resin is mainly used as a continuous phase and a polypropylene resin is used as a dispersed phase among those mainly using a polycarbonate resin.

On the other hand, in recent years, inventions using a propylene-based resin as a continuous phase have been reported as an alternative to a polycarbonate-based resin for reasons such as economy, recyclability, and weight reduction (for example, Patent Documents 4 to 6).
In the diffusion plate using the propylene-based resin described in Patent Documents 4 to 6 for a continuous phase or the like, permeability and diffusivity are evaluated by measuring total light transmittance and total haze.

  However, those using propylene-based resins disclosed in these patent documents cannot be said to satisfy both the permeability and diffusivity at the same time in a balanced manner. Light diffusivity was insufficient. Therefore, in the light diffusing plate using a propylene-based resin, further improvements in both permeability and diffusibility have been demanded.

JP-A-10-003811 JP 2001-031774 A International Publication No. 09/016975 Pamphlet JP 2008-083660 A JP 2010-152230 A JP 2010-152229 A

  In view of the above circumstances, an object of the present invention is to provide a polyolefin resin composition that is excellent in the balance between light transmittance and diffusibility and is useful as a light diffusable sheet material, and a light diffusable sheet comprising the same.

  As a result of intensive studies to solve the above problems, the present inventors have found that a polyolefin having a sea-island structure using a propylene resin composition and a resin incompatible with the propylene resin composition. When the difference between the density of the propylene-based resin composition and the density of the propylene-based resin composition and the density of the incompatible resin is within a specific range, the above-mentioned problem is solved As a result, the present invention has been completed.

That is, according to the first invention of the present invention, a polyolefin resin composition containing the propylene resin composition (A) and the propylene resin composition (A) and the incompatible resin (B). Because
The phase separation structure is a sea-island structure composed of the sea phase of the propylene-based resin composition (A) and the island phase of the resin (B), and the density d _{A of the} propylene-based resin composition (A) and the resin and density _{d B} of (B) is less than the following formula (1),
The propylene-based resin composition (A) is composed of 20 to 100 parts by weight of a propylene-ethylene block copolymer having the following characteristics (i) to (v) and a propylene homopolymer or a propylene-ethylene copolymer 0 to 0: A polyolefin resin composition comprising 80 parts by weight is provided.
0.015 ≦ | d _A −d _B | ≦ 0.050 (1)
(I) Using a metallocene-based catalyst, 30 to 95% by weight of propylene alone or a propylene-ethylene random copolymer component (a) having an ethylene content of 7% by weight or less in the first polymerization step, and a component ( It is a propylene-ethylene block copolymer obtained by successively polymerizing 70 to 5 wt% of a propylene-ethylene random copolymer component (b) containing 3 to 20 wt% more ethylene than a).
(Ii) The melt flow rate (MFR: 230 ° C., 2.16 kg load) is in the range of 0.5 to 100 g / 10 min.
(Iii) The melting peak temperature (Tm) by differential scanning calorimetry (DSC) is in the range of 110 to 150 ° C.
(Iv) The molecular weight distribution (Mw / Mn) measured by gel permeation chromatography (GPC) is in the range of 1.5 to 4.0.
(V) In the temperature-loss tangent curve obtained by solid viscoelasticity measurement, the tan δ curve has a single peak at 0 ° C. or lower.

  Further, according to the second invention of the present invention, in the first invention, the propylene-based resin composition (A) with respect to a total of 100 parts by weight of the propylene-based resin composition (A) and the resin (B). Is contained in an amount of 50 to 90 parts by weight and the resin (B) is contained in an amount of 10 to 50 parts by weight.

According to the third invention of the present invention, in the first or second invention, the resin (B) is an ethylene / α-olefin copolymer (B-1) and a styrene-based elastomer (B-2). There is provided a polyolefin resin composition characterized by being at least one selected from the group consisting of:

Moreover, according to the 4th invention of this invention, the light diffusable sheet formed by shape | molding the polyolefin resin composition of the invention in any one of the 1st- 3rd is provided.

According to the fifth invention of the present invention, in the fourth invention, when the thickness is 1 mm, the total light transmittance is 50% or more and the total haze is 50% or more. A light diffusing sheet is provided.

The polyolefin-based resin composition of the present invention is lightweight, recyclable, and has an excellent balance of permeability and diffusibility. It is a polypropylene-based resin composition useful for light diffusing sheet material because it has a bright effect even though it is not felt. Therefore, when the resin composition is used as a light diffusive sheet, it is possible to obtain a light diffusive sheet that is excellent in both permeability and diffusibility.
In addition, since polyolefin resins are generally known to have a low environmental load, the polyolefin resin composition and the light diffusing sheet of the present invention are more environmentally friendly than light diffusing sheets made of conventional polycarbonate resin compositions. It can be said that there is less concern about the load.

It is a figure which shows the elution amount and elution amount integration by temperature rising elution fractionation (TREF).

The present invention is a polyolefin resin composition containing the propylene resin composition (A) and the propylene resin composition (A) and an incompatible resin (B), wherein the phase separation structure is A sea-island structure composed of a sea phase of the propylene-based resin composition (A) and an island phase of the resin (B), and a density d _{A of the} propylene-based resin composition (A) and a density of the resin (B) d _B relates to a polyolefin resin composition satisfying the following formula (1).
0.015 ≦ | d _A −d _B | ≦ 0.050 (1)
The present invention also relates to a light diffusable sheet formed by molding the polyolefin resin composition.
Hereinafter, each component of the polyolefin resin composition, the light diffusing sheet, and the like will be described in detail.
In the present specification, when a numerical value or a physical property value is inserted before and after using the expression “to”, it is used in the meaning including the numerical value or physical property value before and after that. In the present specification, melt flow rate, differential scanning calorimetry, and gel permeation chromatography may be abbreviated as “MFR”, “DSC”, and “GPC”, respectively.

I. Polyolefin resin composition The polyolefin resin composition of the present invention comprises a propylene resin composition (A) and a polyolefin resin containing the propylene resin composition (A) and an incompatible resin (B). The composition has a sea-island structure in which the phase separation structure is composed of a sea phase of the propylene resin composition (A) and an island phase of the resin (B), and the propylene resin composition (A). The density d _A of the resin and the density d _B of the resin (B) satisfy the following formula (1).
0.015 ≦ | d _A −d _B | ≦ 0.050 (1)

1. Propylene resin composition (A)
The propylene-based resin composition (A) used in the present invention (hereinafter sometimes abbreviated as “resin (A)”) is a resin obtained using propylene as a main component of a monomer, The density d _A is not particularly limited as long as the density d _A satisfies the specific relationship represented by the density d _B of the resin (B) and the above formula (1), and propylene homopolymer, propylene containing propylene as a main component -Α-olefin copolymers, polypropylene resins such as ethylene-propylene-butene terpolymers mainly composed of propylene, etc., and these may be used alone or in combination of two or more. Also good.

(1) Propylene-ethylene block copolymer As a preferable example of the propylene-based resin composition (A), propylene comprising a specific propylene-ethylene block copolymer and / or a propylene homopolymer or a propylene-ethylene copolymer. Based resin composition (A-1).
The propylene-based resin composition (A-1) is preferably 20 to 100 parts by weight of a propylene-ethylene block copolymer having the following characteristics (i) to (v) and / or a propylene homopolymer or propylene- What consists of 0-80 weight part of ethylene copolymers is mentioned.
(I) Using a metallocene-based catalyst, 30 to 95% by weight of propylene alone or a propylene-ethylene random copolymer component (a) having an ethylene content of 7% by weight or less in the first polymerization step, and a component ( It is a propylene-ethylene block copolymer obtained by successively polymerizing 70 to 5 wt% of a propylene-ethylene random copolymer component (b) containing 3 to 20 wt% more ethylene than a).
(Ii) The melt flow rate (MFR: 230 ° C., 2.16 kg load) is in the range of 0.5 to 100 g / 10 min.
(Iii) The melting peak temperature (Tm) by differential scanning calorimetry (DSC) is in the range of 110 to 150 ° C.
(Iv) The molecular weight distribution (Mw / Mn) measured by gel permeation chromatography (GPC) is in the range of 1.5 to 4.0.
(V) In the temperature-loss tangent curve obtained by solid viscoelasticity measurement, the tan δ curve has a single peak at 0 ° C. or lower.

In the first polymerization step, the propylene-ethylene block copolymer having the characteristics (i) to (v) described above is a propylene homopolymer or 30 propylene-ethylene random copolymer components (a) having an ethylene content of 7% by weight or less. After polymerization of ˜95 wt%, in the second polymerization step, 70 to 5 wt% of the propylene-ethylene random copolymer component (b) containing 3 to 20 wt% more ethylene than in the first polymerization step is sequentially polymerized. Can be obtained.
The propylene-ethylene block copolymer here is a propylene-ethylene random copolymer component (a) (hereinafter also referred to as component (a)) and a propylene-ethylene random copolymer component (b). (Hereinafter also referred to as component (b)) is a block copolymer in a general name obtained by sequential polymerization, and component (a) and component (b) are not necessarily combined in a block form. It doesn't have to be a thing.

(1-1) Ethylene content in component (a): [E] _a
Component (a) produced in the first polymerization step is a propylene homopolymer having a relatively high melting point and crystallinity in order to suppress stickiness of the propylene-ethylene block copolymer and to exhibit heat resistance. Or a propylene-ethylene random copolymer having an ethylene content of 7% by weight or less, and in the present specification, “propylene-ethylene random copolymer component (a)” is used as an expression including a propylene homopolymer. And If the ethylene content exceeds 7% by weight, the melting point becomes too low and the heat resistance of the product may be deteriorated. The ethylene content is preferably 5% by weight or less, more preferably 3% by weight or less. If the pellets are sticky, the pellets may stick to each other when stored in a bag. Since the component (a) may be a homopolymer of propylene, the lower limit of the ethylene content [E] _a is 0.

(1-2) Ethylene content in component (b): [E] _b
The component (b) produced in the second polymerization step has a role of a rubber elastic component in the propylene-ethylene block copolymer and is an important component for imparting impact resistance.
The range of the ethylene content of component (b) is defined by the difference [E] _b- [E] _a ([E] _gap ) from the ethylene content of component (a). In order to sufficiently exhibit the effect of imparting impact resistance as a rubber component, [E] _b- [E] _a is preferably in the range of 3 to 20% by weight, more preferably 6 to 18% by weight, Particularly preferred is 8 to 16% by weight.
[E] By setting the _gap to 3% by weight or more, an impact resistance effect can be sufficiently imparted. Moreover, compatibility with the component (a) manufactured at a 1st superposition | polymerization process is acquired because it is 20 weight% or less, and it is preferable from a transparency viewpoint of a propylene-type resin composition (A).

(1-3) Ratio of component (a): W (a) and ratio of component (b): W (b)
The content ratio of W (a), which is the proportion of component (a) constituting the propylene-ethylene block copolymer, and W (b), which is the proportion of component (b), is 30 to 95 wt. % And W (b) is preferably in the range of 70 to 5% by weight.
If the proportion of W (a) is less than 30% by weight, stickiness of the product may occur and heat resistance may be reduced. On the other hand, if the proportion of W (a) exceeds 95% by weight, the rubber elasticity of the ethylene-propylene block copolymer is insufficient and the impact resistance may be insufficient. Preferably, the proportion of W (a) is in the range of 40 to 90% by weight, more preferably 50 to 80% by weight. That is, the proportion of W (b) is preferably 60 to 10% by weight, more preferably 50 to 20% by weight.

(1-4) [E] _a and [E] _b and specific amounts of each component W (a) and W (b) The ethylene content and amount of each component (a) and (b) are the material balance at the time of manufacture. Although it is possible to specify by (material balance), for example, these can be specified more accurately by using the following analysis.

(1-4-1) Identification of each component amount W (a) and W (b) by temperature rising elution fractionation (TREF) The method for evaluating the crystalline distribution of propylene-ethylene random copolymer by TREF This method is well known to those skilled in the art. For example, detailed measurement methods are shown in the following documents.
Appl. Polym. Symp. 45, 1-24 (1990)
Polym. Sci. 98, 1-47 (1990)
Polymer; 36, 8, 1639-1654 (1995)
The propylene-ethylene block copolymer in the present invention has a large difference in crystallinity between the component (a) and the component (b), and each molecular weight distribution is produced by using a metallocene catalyst. Therefore, it is possible to distinguish both of them with high accuracy by TREF.
A specific method will be described with reference to the figure showing the elution amount and the elution amount integration by TREF in FIG. In the TREF elution curve (plot of elution amount with respect to temperature), the component (a) and the component (b) have different TREF elution temperatures T (a ) And T (b) show the peak of the elution temperature, and the difference is sufficiently large so that separation is possible at an intermediate temperature T (c) (= {T (a) + T (b)} / 2). is there.

Further, the lower limit of the TREF measurement temperature is −15 ° C. in the apparatus used for the measurement in the examples of the present specification, but this is the case when the crystallinity of the component (b) is very low or an amorphous component. In the measurement method, a peak may not be shown in the measurement temperature range. (In this case, the concentration of the component (b) dissolved in the solvent is detected at the measurement temperature lower limit (that is, −15 ° C.).)
At this time, T (b) is considered to exist below the lower limit of the measurement temperature, but the value cannot be measured. In such a case, T (b) is the lower limit of the measurement temperature. Defined as ° C.
Here, if the integrated amount of the components eluted before T (c) is defined as W (b) wt%, and the integrated amount of the portion eluted at T (c) or higher is defined as W (a) wt%, W (b) Almost corresponds to the amount of the component (b) having low crystallinity or amorphous, and the integrated amount W (a) of the component eluted at T (c) or higher is the component (a) having relatively high crystallinity. Almost corresponds to the amount of. The elution amount curve obtained by TREF and the above-described methods for calculating the various temperatures and amounts obtained therefrom are performed as illustrated in FIG.

(1-4-2) TREF measurement method In the present invention, TREF is specifically measured as follows.
A sample is dissolved in o-dichlorobenzene (containing 0.5 mg / mL BHT) at 140 ° C. to obtain a solution. This is introduced into a 140 ° C. TREF column, cooled to 100 ° C. at a rate of 8 ° C./min, subsequently cooled to −15 ° C. at a rate of 4 ° C./min, and held for 60 minutes. Thereafter, o-dichlorobenzene (containing 0.5 mg / mL BHT) as a solvent is flowed through the column at a flow rate of 1 mL / min, and components dissolved in o-dichlorobenzene at −15 ° C. are eluted in the TREF column for 10 minutes. Next, the column is linearly heated to 140 ° C. at a heating rate of 100 ° C./hour to obtain an elution curve.

(1-4-3) Ethylene content in each component [E] _a and [E] _b specific (a) Separation of component (a) and component (b) T (c) determined by TREF measurement at the destination Based on the temperature rising column fractionation method using a preparative fractionator, the soluble component (b) in T (c) and the insoluble component (a) in T (c) are fractionated, and each component is analyzed by NMR. Determine the ethylene content.
The temperature rising column fractionation method refers to a measurement method disclosed in, for example, Macromolecules, 21 314 to 319 (1988). Specifically, in the examples of the present specification, the following method was used.

(B) Fractionation condition A cylindrical column having a diameter of 4.3 mm and a height of 150 mm is filled with a glass bead carrier (80 to 100 mesh) and maintained at 140 ° C. Next, 200 mL of a sample o-dichlorobenzene solution (5 mg / mL) dissolved at 140 ° C. is introduced into the column. Thereafter, the temperature of the column is cooled to 0 ° C. at a rate of temperature decrease of 10 ° C./hour. After holding at 0 ° C. for 1 hour, the column temperature is heated to T (c) at a heating rate of 10 ° C./hour and held for 1 hour. Note that the temperature control accuracy of the column through a series of operations is ± 1 ° C.
Next, while maintaining the column temperature at T (c), 800 mL of o (dichlorobenzene) of T (c) is allowed to flow at a flow rate of 20 mL / min, whereby components soluble in T (c) existing in the column are obtained. Elute and collect.
Next, the column temperature is increased to 140 ° C. at a rate of temperature increase of 10 ° C./min, held at 140 ° C. for 1 hour, and then 800 mL of a 140 ° C. solvent (o-dichlorobenzene) is allowed to flow at a solvent flow rate of 1 mL / min. Insoluble components are eluted and collected at T (c).
The solution containing the polymer obtained by fractionation is concentrated to 20 mL using an evaporator and then precipitated in 5 times the amount of methanol. The precipitated polymer is recovered by filtration and then dried overnight in a vacuum dryer.

(C) ^{13 C-NMR} according to the measurement the fractionated by components obtained ethylene content ^{(a) (b) 13 C} -NMR spectrum ethylene content was determined according to the following conditions by complete proton decoupling method for each It is obtained by analyzing. In addition, the apparatus used in the Example is an apparatus having a carbon nuclear resonance frequency of 100 MHz or more, and the same apparatus as described below may be used.
Model: GSX-400 manufactured by JEOL Ltd.
Solvent: o-dichlorobenzene / heavy benzene = 4/1 (volume ratio)
Concentration: 100 mg / mL
Temperature: 130 ° C
Pulse angle: 90 °
Pulse interval: 15 seconds Integration count: 5,000 times or more The attribution of the spectrum may be performed with reference to Macromolecules, 17 1950 (1984), for example. The attribution of the spectrum measured by the said conditions is as Table-1. In Table 1, symbols such as Sαα are in accordance with the notation of Carman et al. (Macromolecules, 10536 (1977)), P represents a methyl carbon, S represents a methylene carbon, and T represents a methine carbon.

Hereinafter, when “P” is a propylene unit in a copolymer chain and “E” is an ethylene unit, six kinds of triads of PPP, PPE, EPE, PEP, PEE, and EEE may exist in the chain. As described in Macromolecules, 15 1150 (1982), the concentration of these triads and the peak intensity of the spectrum are linked by the following relational expressions [1] to [6].
[PPP] = k × I (Tββ) [1]
[PPE] = k × I (Tβδ) [2]
[EPE] = k × I (Tδδ) [3]
[PEP] = k × I (Sββ) [4]
[PEE] = k × I (Sβδ) [5]
[EEE] = k × {I (Sδδ) / 2 + I (Sγδ) / 4} [6]
Here, [] indicates the fraction of triads, for example, [PPP] is the fraction of PPP triads in all triads. Therefore,
[PPP] + [PPE] + [EPE] + [PEP] + [PEE] + [EEE] = 1 [7]
It is. Further, k is a constant, I indicates the spectral intensity, and for example, I (Tββ) means the intensity of the peak at 28.7 ppm attributed to Tββ.

By using the relational expressions [1] to [7] above, the fraction of each triad is obtained, and the ethylene content is obtained from the following equation.
Ethylene content (mol%) = ([PEP] + [PEE] + [EEE]) × 100
Note that the propylene random copolymer that can be used in the present invention contains a small amount of a propylene hetero bond (2,1-bond and / or 1,3-bond), thereby causing the following minute peak. Arise.

In order to obtain an accurate ethylene content, it is necessary to include these peaks derived from heterogeneous bonds in the calculation, but it is difficult to completely separate and identify the peaks derived from heterogeneous bonds, and the amount of heterogeneous bonds is small. Therefore, the ethylene content of the present invention is determined using the relational expressions [1] to [7] as in the case of the analysis of the copolymer produced with a Ziegler catalyst that does not substantially contain a heterogeneous bond. .
Conversion of the ethylene content from mol% to wt% can be performed using the following formula.
Ethylene content (% by weight) = (28 × X / 100) / {28 × X / 100 + 42 × (1−X / 100)} × 100
Here, X is the ethylene content in mol%.
Further, the ethylene content [E] _W of the entire propylene-ethylene block copolymer is calculated from the ethylene contents [E] _a , [E] _b and TREF of the components (a) and (b) measured above. From the weight ratios W (a) and W (b) wt% of each component, the following formula is used.
[E] _W = {[E] _a × W (a) + [E] _b × W (b) / 100 (% by weight)

(1-5) Melt flow rate (MFR)
The melt flow rate (MFR) of propylene-ethylene block copolymer that can be used in the present invention is preferably 0.5 to 100 g / 10 minutes, more preferably 1 to 50 g / 10 minutes, and particularly preferably. 2 to 35 g / 10 min. If the MFR is less than 0.5 g / 10 minutes, molding may be difficult, and if it exceeds 100 g / 10 minutes, impact resistance may not be expected.
The melt flow rate (MFR) is easily adjusted by adjusting the temperature and pressure, which are the polymerization conditions for propylene-ethylene block copolymerization, or by controlling the amount of hydrogen added to the chain transfer agent such as hydrogen during polymerization. be able to.
Here, MFR is a value measured according to JIS K7210 at a temperature of 230 ° C. and a load of 2.16 kg.

(1-6) Melting peak temperature (Tm)
The melting peak temperature (Tm) measured by a differential scanning calorimeter (DSC) of propylene-ethylene block copolymer used in the present invention is preferably in the range of 110 to 150 ° C, and preferably 120 to 140 ° C. Is more preferable. Those having a Tm of less than 110 ° C are not preferable because the cooling and solidifying rate of the molten propylene resin composition (A) is slow and may deteriorate moldability, and impact resistance may be deteriorated when the temperature exceeds 150 ° C. This is not preferable. In order to adjust Tm, it can adjust easily by controlling the quantity of the alpha olefin supplied to a polymerization reaction system.
Here, a specific measurement of Tm is performed by using a differential scanning calorimeter (DSC), taking a sample amount of 5.0 mg, holding at 200 ° C. for 5 minutes, and then crystallizing at 40 ° C. at a rate of 10 ° C./min. Further, the peak position of the curve drawn when melted at a heating rate of 10 ° C./min is defined as a melting peak temperature Tm (° C.).

(1-7) Molecular weight distribution (Mw / Mn)
The molecular weight distribution (Mw / Mn) measured by the gel permeation (GPC) method of propylene-ethylene block copolymer used in the present invention is preferably in the range of 1.5 to 4.0. More preferably, it is 8 or more and less than 3.0. Mw / Mn less than 1.5 is not practical because it is difficult to produce on an industrial scale with the current polymerization technology, and if it exceeds 4.0, the product (pellet) may become sticky, which is not preferable. . When narrowing the molecular weight distribution of the propylene-ethylene block copolymer, use a metallocene catalyst described later, or polymerize the propylene-ethylene block copolymer and then melt knead using an organic peroxide. Can be adjusted. When making it wide, it can adjust by superposing | polymerizing using the catalyst system which used together 2 or more types of metallocene catalyst components, or the catalyst system which used 2 or more types of metallocene complexes together.
Here, the molecular weight distribution is obtained by the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn), and is obtained by measurement by a gel permeation chromatography (GPC) method.
Conversion from the retention volume to the molecular weight is performed using a calibration curve prepared in advance with standard polystyrene.

The standard polystyrenes used are all the following brands manufactured by Tosoh Corporation.
F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000
A calibration curve is prepared by injecting 0.2 ml of a solution dissolved in o-dichlorobenzene (containing 0.5 mg / ml BHT) so that each is 0.5 mg / ml.
The calibration curve uses a cubic equation obtained by approximation by the least square method. The following numerical value is used for [η] = K × Mα in the viscosity formula used for conversion to molecular weight.
PS: K = 1.38 × 10 −4 α = 0.7
PP: K = 1.03 × 10 −4 α = 0.78
The measurement conditions for GPC are as follows.
Apparatus: GPC (ALC / GPC 150C) manufactured by WATERS
Detector: MIRAN 1A IR detector (measured wavelength: 3.42 μm) manufactured by FOXBORO
Column: AD806M / S (3 pieces) manufactured by Showa Denko KK
Mobile phase solvent: o-dichlorobenzene Measurement temperature: 140 ° C.
Flow rate: 1.0 ml / min Injection volume: 0.2 ml
Sample preparation: Prepare a 1 mg / ml solution using o-dichlorobenzene (containing 0.5 mg / ml BHT) and dissolve it at 140 ° C. for about 1 hour.

(1-8) Definition by peak of tan δ curve In the present invention, in order to maintain good compatibility and maintain transparency, component (a) and component (a) constituting the propylene-ethylene block copolymer to be used ( b) must not be phase separated. The phase separation conditions are affected not only by the ethylene content but also by the molecular weight and composition. Therefore, in addition to the above ethylene content conditions, the temperature obtained by solid viscoelasticity measurement (DMA) as described in detail below. -In a loss tangent (tan-delta) curve, it is preferable that a tan-delta curve has a single peak below 0 degreeC.
When the propylene-ethylene block copolymer has a phase separation structure, the glass transition temperature of the amorphous part contained in the component (a) is different from the glass transition temperature of the amorphous part contained in the component (b). , There will be multiple peaks. Conversely, when they are compatible, both components are mixed in the order of molecules and have a single peak at a temperature intermediate between the glass transition temperatures of both components. That is, whether the phase separation structure is taken or not can be determined in the temperature-tan δ curve in the solid viscoelasticity measurement. In order to maintain the transparency of the propylene-ethylene block copolymer, the tan δ curve is 0 ° C. or less. Preferably have a single peak.
Specifically, solid viscoelasticity measurement is performed by applying a sinusoidal strain of a specific frequency to a strip-shaped sample piece and detecting the generated stress. Here, the frequency is 1 Hz and the measurement temperature is raised stepwise from −60 ° C. until the sample is melted and cannot be measured. Further, it is recommended that the magnitude of distortion is about 0.1 to 0.5%. From the obtained stress, the storage elastic modulus G ′ and the loss elastic modulus G ″ are obtained by a known method, and the loss tangent (= loss elastic modulus / storage elastic modulus) defined by this ratio is plotted against the temperature. A sharp single peak is shown in the temperature range of 0 ° C. or lower, and generally the peak of the tan δ curve at 0 ° C. or lower is observed for the glass transition of the amorphous part. ° C).

(2) Propylene-ethylene block copolymer production method (2-1) Metallocene catalyst The method of producing a propylene-ethylene block copolymer that can be suitably used in the present invention requires the use of a metallocene catalyst. It is what.
It is well known to those skilled in the art that stickiness and bleedout deteriorate when the molecular weight and crystallinity distribution are wide in the propylene-ethylene random copolymer, but also in the propylene-ethylene block copolymer used in the present invention, In order to suppress stickiness and bleed-out, it is necessary to perform polymerization using a metallocene catalyst that has a narrow molecular weight and crystallinity distribution.

The type of the metallocene-based catalyst is not particularly limited as long as it can produce a copolymer having the performance of the present invention. However, in order to satisfy the requirements of the present invention, for example, the following components ( It is preferable to use a metallocene catalyst comprising a), (b), and component (c) used as necessary.
Component (A): At least one metallocene transition metal compound selected from transition metal compounds represented by the following formula Component (A): At least one selected from the following (A-1) to (A-4) A particulate carrier carrying a solid component (a-1) organic aluminum oxy compound,
(I-2) Fine carrier (I-3) solid acid fine particles (B) carrying an ionic compound or Lewis acid capable of reacting with component (A) to convert component (A) into a cation 4) Ion exchange layered silicate,
Ingredient (U): Organoaluminum compound.

(2-2) Component (A)
As the component (a), at least one metallocene transition metal compound selected from transition metal compounds represented by the following formula can be used.
^{_{Q (C 5 H 4-a}} R 1 a) (C 5 H 4-b R 2 b) MeXY
[Wherein Q represents a divalent linking group that bridges two conjugated five-membered ring ligands, Me represents a metal atom selected from titanium, zirconium, and hafnium, and X and Y represent a hydrogen atom, a halogen atom, An atom, a hydrocarbon group, an alkoxy group, an amino group, a nitrogen-containing hydrocarbon group, a phosphorus-containing hydrocarbon group or a silicon-containing hydrocarbon group is shown, and X and Y may be independently, that is, the same or different. R ¹ and R ² are hydrogen, hydrocarbon group, halogenated hydrocarbon group, silicon-containing hydrocarbon group, nitrogen-containing hydrocarbon group, oxygen-containing hydrocarbon group, boron-containing hydrocarbon group, or phosphorus-containing hydrocarbon group. Show. a and b are the number of substituents. ]

Specifically, Q represents a divalent linking group that bridges two conjugated five-membered ring ligands, and has, for example, a divalent hydrocarbon group, a silylene group, an oligosilylene group, or a hydrocarbon group as a substituent. Examples include a silylene group, an oligosilylene group, or a germylene group having a hydrocarbon group as a substituent. Among these, preferred is a silylene group having a divalent hydrocarbon group and a hydrocarbon group as a substituent.
X and Y represent a hydrogen atom, a halogen atom, a hydrocarbon group, an alkoxy group, an amino group, a nitrogen-containing hydrocarbon group, a phosphorus-containing hydrocarbon group, or a silicon-containing hydrocarbon group. Among these, hydrogen is preferable , Chlorine, methyl, isobutyl, phenyl, dimethylamide, diethylamide group and the like. X and Y may be independent, that is, may be the same or different.
R ¹ and R ² are hydrogen, hydrocarbon group, halogenated hydrocarbon group, silicon-containing hydrocarbon group, nitrogen-containing hydrocarbon group, oxygen-containing hydrocarbon group, boron-containing hydrocarbon group, or phosphorus-containing hydrocarbon group. Represents. Specific examples of the hydrocarbon group include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, a phenyl group, a naphthyl group, a butenyl group, and a butadienyl group. In addition, as halogenated hydrocarbon group, silicon-containing hydrocarbon group, nitrogen-containing hydrocarbon group, oxygen-containing hydrocarbon group, boron-containing hydrocarbon group, or phosphorus-containing hydrocarbon group, methoxy group, ethoxy group, phenoxy group Typical examples include trimethylsilyl group, diethylamino group, diphenylamino group, pyrazolyl group, indolyl group, dimethylphosphino group, diphenylphosphino group, diphenylboron group, and dimethoxyboron group. In these, it is preferable that it is a C1-C20 hydrocarbon group, and it is especially preferable that they are a methyl group, an ethyl group, a propyl group, and a butyl group. By the way, adjacent R ¹ and R ² may combine to form a ring, on which a hydrocarbon group, halogenated hydrocarbon group, silicon-containing hydrocarbon group, nitrogen-containing hydrocarbon group, oxygen-containing You may have a substituent which consists of a hydrocarbon group, a boron containing hydrocarbon group, or a phosphorus containing hydrocarbon group.
Me is a metal atom selected from titanium, zirconium and hafnium, preferably zirconium and hafnium.

Among the components (a) described above, those preferable for the production of the propylene-ethylene random block copolymer used in the present invention are crosslinked with a silylene group, a germylene group or an alkylene group having a hydrocarbon substituent. It is a transition metal compound comprising a ligand having a substituted cyclopentadienyl group, a substituted indenyl group, a substituted fluorenyl group, and a substituted azulenyl group, and is particularly preferably crosslinked by a silylene group having a hydrocarbon substituent or a gelmylene group. And a transition metal compound comprising a ligand having a 2,4-position substituted indenyl group and a 2,4-position substituted azulenyl group.
Non-limiting specific examples include dimethylsilylene bis (2-methyl-4-phenylindenyl) zirconium dichloride, diphenylsilylene bis (2-methyl-4-phenylindenyl) zirconium dichloride, dimethylsilylene bis (2-methyl). Benzoindenyl) zirconium dichloride, dimethylsilylenebis {2-isopropyl-4- (3,5-diisopropylphenyl) indenyl} zirconium dichloride, dimethylsilylenebis (2-propyl-4-phenanthrylindenyl) zirconium dichloride, dimethyl Silylene bis (2-methyl-4-phenylazurenyl) zirconium dichloride, dimethylsilylene bis {2-methyl-4- (4-chlorophenyl) azurenyl} zirconium dichloride, dimethylsilylene bi (2-Ethyl-4-phenylazurenyl) zirconium dichloride, dimethylsilylenebis (2-isopropyl-4-phenylazurenyl) zirconium dichloride, dimethylsilylenebis {2-ethyl-4- (2-fluorobiphenyl) azurenyl} zirconium Examples thereof include dichloride and dimethylsilylenebis {2-ethyl-4- (4-t-butyl-3-chlorophenyl) azurenyl} zirconium dichloride. A compound in which the silylene group of these specific examples is replaced with a germylene group and zirconium is replaced with hafnium is also exemplified as a suitable compound. In addition, since the catalyst component is not an important element of the present invention, it avoids complicated listing and is limited to a representative example, but it is obvious that the effective range of the present invention is not limited by this. It is.

(2-3) Component (I)
As the component (a), at least one solid component selected from the components (a-1) to (a-4) described above is used. Each of these components is a known component, and can be appropriately selected from known technologies and used. Specific examples and manufacturing methods thereof are described in detail in JP-A No. 2002-284808, JP-A No. 2002-53609, JP-A No. 2002-69116, JP-A No. 2003-105015, and the like.
Here, as the particulate carrier used for the component (I-1) and the component (I-2), inorganic oxides such as silica, alumina, magnesia, silica alumina, silica magnesia, magnesium chloride, magnesium oxychloride, chloride Examples thereof include inorganic halides such as aluminum and lanthanum chloride, and porous organic carriers such as polypropylene, polyethylene, polystyrene, styrene divinyl benzene copolymer, and acrylic acid copolymer.
Further, as a non-limiting specific example of the component (a), a fine particle carrier on which methylalumoxane, isobutylalumoxane, methylisobutylalumoxane, aluminum butylboronate tetraisobutyl and the like are supported as the component (a-1) As component (ii-2), triphenylborane, tris (3,5-difluorophenyl) borane, tris (pentafluorophenyl) borane, triphenylcarbonium tetrakis (pentafluorophenyl) borate, N, N-dimethyl Particulate carrier carrying anilinium tetrakis (pentafluorophenyl) borate, etc. as component (I-3), alumina, silica alumina, magnesium chloride, etc. as component (I-4), montmorillonite, zakonite, beidellite , Nontronic , Saponite, hectorite, stevensite, bentonite, smectite group such as taeniolite, vermiculite, and the like mica group. These may form a mixed layer.
Among the above components (a), particularly preferred are the ion-exchange layered silicates of component (a-4), and more preferred are chemical treatments such as acid treatment, alkali treatment, salt treatment, and organic matter treatment. It is an ion exchange layered silicate applied.

(2-4) Component (c)
Examples of organoaluminum compounds used as component (c) as needed are:
Formula AlRaP _3-a
(Wherein R is a hydrocarbon group having 1 to 20 carbon atoms, P is hydrogen, halogen, alkoxy group, a is a number of 0 <a ≦ 3), trimethylaluminum, triethylaluminum, tripropylaluminum, tri Trialkylaluminum such as isobutylaluminum or halogen or alkoxy-containing alkylaluminum such as diethylaluminum monochloride, diethylaluminum monomethoxide. In addition, aluminoxanes such as methylaluminoxane can also be used. Of these, trialkylaluminum is particularly preferred.

(2-5) Formation of catalyst Component (a) is contacted with component (a) and, if necessary, component (c) to form a catalyst. The contact method is not particularly limited, but the contact can be made in the following order. Moreover, this contact may be performed not only at the time of catalyst preparation but also at the time of prepolymerization with olefin or at the time of polymerization of olefin.
1) Component (a) and component (a) are brought into contact.
2) Add component (c) after contacting component (a) and component (a).
3) Component (a) is added after contacting component (a) and component (c).
4) Add component (a) after contacting component (a) and component (c).
In addition, you may contact three components simultaneously.

  The amount of components (a), (b) and (c) used in the present invention is arbitrary. For example, the amount of component (a) used relative to component (a) is preferably in the range of 0.1 μmol to 1,000 μmol, particularly preferably 0.5 μmol to 500 μmol, relative to 1 g of component (a). The amount of component (c) used relative to component (a) is preferably such that the amount of transition metal is 0.001 to 100 μmol, particularly preferably 0.005 to 50 μmol, relative to 1 g of component (a). Therefore, the amount of the component (c) relative to the component (a) is preferably in the range of 10-5 to 50, particularly preferably 10-4 to 5 in terms of the molar ratio of the transition metal.

The catalyst used in the propylene-ethylene block copolymer preferably used in the present invention is preferably subjected to a prepolymerization treatment in which a small amount of polymer is brought into contact with an olefin in advance. The olefin to be used is not particularly limited, but ethylene, propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, 3-methyl-1-butene, vinylcycloalkane, styrene and the like can be used. It is possible to use, and it is particularly preferable to use propylene. The olefin can be supplied by any method, such as a supply method for maintaining the olefin at a constant speed or in a constant pressure state, a combination thereof, or a stepwise change. The prepolymerization temperature and time are not particularly limited, but are preferably in the range of −20 ° C. to 100 ° C. and 5 minutes to 24 hours, respectively. The amount of prepolymerization is preferably 0.01 to 100, more preferably 0.1 to 50 with respect to the component (A). After completion of the prepolymerization, the catalyst can be used as it is, depending on the usage form of the catalyst. However, if necessary, drying can be performed.
Furthermore, a polymer such as polyethylene, polypropylene, or polystyrene, or an inorganic oxide solid such as silica or titania can be allowed to coexist during or after the contact of the above components.

(2-6) Polymerization Method (2-6-1) Sequential Polymerization When producing and implementing a propylene-ethylene block copolymer suitably used in the present invention, component (a) and component (b) are sequentially polymerized. It is necessary.
When the propylene-ethylene copolymer is a random copolymer obtained by simply copolymerizing propylene with ethylene, if the ethylene content is low, the flexibility / impact resistance and transparency are not sufficient, and the flexibility / impact resistance When the ethylene content is increased in order to improve transparency, the heat resistance deteriorates, and it is difficult to satisfy all of these.
Therefore, in the present invention, the propylene-ethylene block copolymer is a block copolymer obtained by sequentially polymerizing components having different ethylene contents in the first polymerization step and the second polymerization step. Necessary to balance all heat resistance.
In the present invention, since a copolymer having a low molecular weight and easily sticking alone may be used as the component (b), the component (a) is polymerized in order to prevent problems such as adhesion to the reactor. It is necessary to use a method for polymerizing component (b).
When performing sequential polymerization, either a batch method or a continuous method can be used, but it is generally desirable to use a continuous method from the viewpoint of productivity.

In the case of a batch method, it is possible to polymerize component (a) and component (b) separately using a single reactor by changing the polymerization conditions with time. As long as the effect of the present invention is not impaired, a plurality of reactors may be connected in parallel.
In the case of a continuous process, it is necessary to use a production facility in which two or more reactors are connected in series because it is necessary to individually polymerize the component (a) and the component (b). A plurality of reactors may be connected in series and / or in parallel for each of component (a) and component (b).

(2-6-2) Polymerization process As the polymerization process, any polymerization method such as a slurry method, a bulk method, or a gas phase method can be used. Although supercritical conditions can be used as intermediate conditions between the bulk method and the gas phase method, they are substantially the same as the gas phase method, and are therefore included in the gas phase method without particular distinction.
Since component (b) is readily soluble in organic solvents such as hydrocarbons and liquefied propylene, it is desirable to use a gas phase method for the production of component (b).
There is no particular problem in using any process for the production of component (a), but in the case of producing component (a) having relatively low crystallinity, a vapor phase method is used to avoid problems such as adhesion. It is desirable to use
Therefore, it is most desirable to first polymerize component (a) by the bulk method or gas phase method and then polymerize component (b) by the gas phase method using a continuous method.

(2-6-3) Other polymerization conditions The polymerization temperature can be used without any particular problem as long as it is within a commonly used temperature range. Specifically, a range of 0 ° C. to 200 ° C., more preferably 40 ° C. to 100 ° C. can be used.
The polymerization pressure varies depending on the process to be selected, but can be used without any problem as long as it is in a pressure range usually used. Specifically, it is a relative pressure with respect to the atmospheric pressure, and a range from 0 MPa to 200 MPa, more preferably from 0.1 MPa to 50 MPa can be used. At this time, an inert gas such as nitrogen may coexist.
When the component (a) is sequentially polymerized in the first polymerization step and the component (b) is sequentially polymerized in the second polymerization step, it is desirable to add a polymerization inhibitor into the system in the second weight polymerization step. In the case of producing a propylene-ethylene block copolymer, the addition of a polymerization inhibitor to a reactor that performs ethylene-propylene random copolymerization in the second polymerization step results in particle properties (such as fluidity) and gel of the resulting powder. Product quality can be improved. Various technical studies have been made on this method, and examples thereof include Japanese Patent Publication No. 63-54296, Japanese Patent Application Laid-Open No. 7-25960, Japanese Patent Application Laid-Open No. 2003-2939, and the like. It is desirable to apply the method to the present invention.

(3) Method for controlling constituent elements of propylene-ethylene block copolymer Each element of the propylene-ethylene block copolymer used in the present invention is controlled as follows, and is manufactured so as to satisfy preferable constituent requirements for the present invention. be able to.

(3-1) Component (a)
For component (a), it is preferable to control the elution temperature T (a) by ethylene content [E] _a and TREF.
In the present invention, in order to control [E] _a within _a predetermined range, the amount ratio of propylene and ethylene supplied to the polymerization tank in the first polymerization step may be appropriately adjusted. The relationship between the supply ratio and the ethylene content in the resulting propylene-ethylene random copolymer varies depending on the type of metallocene catalyst used, but the component (a) having the ethylene content [E] _a required by adjusting the supply ratio is selected. Can be manufactured.
For example, when [E] _a is controlled to be less than 7% by weight, the supply weight ratio of ethylene to propylene may be set to a range of 0.3 or less, preferably 0.2 or less.
At this time, the molecular weight distribution of the component (a) is narrow, and the elution temperature T (a) by TREF of the component (a) decreases as [E] _a increases.

(3-2) Component (b)
For component (b), it is preferable to control the elution temperature T (b) and [η] cxs by ethylene content [E] _b and TREF.
In the present invention, in order to control [E] _b within a predetermined range, the ratio of ethylene supply to propylene in the second step may be controlled in the same manner as [E] _a . For example, when [E] _b is controlled to 3 to 27 wt%, the supply weight ratio of ethylene to propylene may be in the range of 0.005 to 6, preferably in the range of 0.01 to 3.
At this time, although the crystallinity distribution of the component (b) is slightly increased as the ethylene content is increased, the T (b) is decreased as the [E] _b is increased as in the component (a).

(3-3) W (a) and W (b)
The amount W (a) of the component (a) and the amount W (b) of the component (b) change the ratio of the production amount of the first polymerization step for producing the component (a) and the production amount of the component (b). Can be controlled. For example, in order to increase W (a) and reduce W (b), the production amount of the second polymerization step may be reduced while maintaining the production amount of the first polymerization step, which is the residence time of the second polymerization step. It can be easily controlled by shortening the polymerization time, lowering the polymerization temperature, or increasing the amount of the polymerization inhibitor. The reverse is also true.
When actually setting the conditions, it is necessary to consider the activity decay. That is, in the range of ethylene content [E] _a and [E] _b carried out in the present invention, generally, when the ratio of ethylene supply to propylene is increased in order to increase the ethylene content, the polymerization activity increases, and at the same time The activity decay tends to increase. Therefore, in order to maintain the activity of the second polymerization step, it is necessary to suppress the polymerization activity of the first polymerization step. Specifically, in the first polymerization step, the ethylene content [E] a is lowered to reduce the production amount. W (a) is lowered, and if necessary, the polymerization temperature is lowered and / or the polymerization time (residence time) is shortened, or the ethylene content [E] _b is increased in the second polymerization step, and the production amount W ( The conditions may be set by a method that raises b) and, if necessary, raises the polymerization temperature and / or lengthens the polymerization time (residence time).

(3-4) Glass transition temperature Tg
The propylene-ethylene block copolymer used in the present invention has a single glass transition temperature Tg of 0 ° C. or less, which is a temperature at which the tan δ curve obtained in the temperature-loss tangent curve obtained by solid viscoelasticity measurement shows a peak. It is preferable to have a peak. For Tg has a single peak, the component (a) ethylene content in the _{[E] a} and the ethylene content in component (B) of the difference between _{[E] b [E] gap} (= [E _{] b} - [E] _a) 20% by weight or less, preferably 16 wt% or less, may be reduced to _{[E] gap} to the extent that Tg in actual measurement is a single peak.
The ethylene content in component (a) according to [E] _a, to enter the ethylene content [E] _b in component (b) in the proper range, the supply weight of ethylene to propylene in the polymerization of component (b) By setting the ratio, a propylene-ethylene block copolymer having a predetermined [E] _gap can be obtained.
Moreover, Tg of the propylene-ethylene block copolymer which does not take a phase-separation structure used for this invention is ethylene content [E] _{a in} a component (a), and ethylene content in _a component (b) [ E] _b , and the amount ratio of both components is affected. In the present invention, the amount of component (b) is from 5 to 70% by weight, but in this range, Tg is more strongly affected by the ethylene content [E] _b in component (b).
That is, Tg reflects the glass transition of the amorphous part, but in the propylene-ethylene block copolymer used in the present invention, the component (a) has crystallinity and relatively few amorphous parts. On the other hand, the component (b) is low crystalline or amorphous and most of it is an amorphous part. Therefore, the value of Tg is controlled by substantially _{[E] b,} the control method of _{[E] b} are as described above.

(4) Propylene homopolymer or propylene-ethylene copolymer The propylene homopolymer or propylene-ethylene copolymer used in the propylene-based resin composition (A-1) is not particularly limited. A polymer having a density of 0.90 to 0.93 and a propylene-ethylene copolymer of 0.88 to 0.91 can be used.

(5) Production method of propylene-based resin composition (A) The production method of propylene-based resin composition (A) is not particularly limited, and for example, the above-described propylene-ethylene block copolymer or propylene homopolymer In some cases, a propylene homopolymer or a propylene-ethylene copolymer may be added to a commonly used means such as a Henschel mixer, a super mixer, a ribbon blender, etc. It can be produced by melt-kneading in a temperature range of 180 to 280 ° with a screw extruder, twin screw extruder, Banbury mixer, plastic bender, roll or the like.
The order of kneading is not particularly limited, but kneading at a time is preferable for the reason of dispersibility.
In this invention, it is preferable to use said propylene-ethylene block copolymer in the ratio of 20-100 weight part, and a propylene homopolymer or a propylene-ethylene copolymer in the ratio of 0-80 weight part. If the above range is exceeded, the total haze may be reduced.

2. Resin (B)
The polyolefin resin composition of the present invention contains a resin (B) that is incompatible with the propylene resin composition (A). In the present specification, “polypropylene resin and incompatible resin (B)” is low in compatibility with polypropylene resin and forms a sea-island structure when blended with propylene-based resin composition (A). The type is not particularly limited as long as it can be used.
However, the density d _B of the propylene resin composition (A) Density d _A and incompatible resin (B), it is necessary to satisfy the following formula (1).
0.015 ≦ | d _A −d _B | ≦ 0.050 (1)
And density d _B of the propylene resin composition (A) Density d _A and incompatible resin (B) is not satisfied the formula (1), if the absolute value of the density difference is less than 0.015 The total haze may be reduced, which is not preferable. On the other hand, if the absolute value of the density difference exceeds 0.050, the total light transmittance may be decreased, which is not preferable.
The density is a value measured at 23 ° C. according to JIS K7112, and the unit is g / cm ³ .

  The resin (B) used in the polyolefin resin composition of the present invention preferably has a propylene content of 20 mol% or less. More preferably, it is a resin containing no more than 10 mol%, more preferably propylene. Exceeding the above range is not preferable because when it is blended with the propylene-based resin composition (A), a sea-island structure may not be formed.

The resin (B) used in the polyolefin resin composition of the present invention may be used by appropriately selecting a resin that satisfies the formula (1) with respect to the propylene resin composition (A). That is, the density of the propylene-based resin composition (A) is measured based on JIS K7112, and the resin (B) having a density suitable for the density may be selected.
For example, when the propylene resin composition (A-1) mentioned as a suitable example of the propylene resin composition (A) is used, the density is usually in the range of 0.880 ≦ d _A ≦ 0.910. because falling, as the resin (B) a density _{d B} may be selected those in the range of 0.830 ≦ _{d B} ≦ 0.863 or 0.893 ≦ _{d B} ≦ 0.960.
Alternatively, the resin (B) may be determined, the density based on JIS K7112 may be measured, and the propylene-based resin composition (A) may be selected so as to satisfy the formula (1).

Further, it is generally known that there is a correlation between a density difference and a refractive index difference in a transparent resin. Therefore, the density difference defined in the present application can be replaced with a difference in refractive index and displayed. For example, the expression (1) relating to the absolute value of the density difference described above is expressed by the following expression (2) by the absolute value of the difference in refractive index.
0.009 ≦ | D _A −D _B | ≦ 0.030 (2)
_{(D A} is the refractive index of the propylene resin composition (A), _{D B} is the refractive index of the resin (B).)
Also in this case, the resin (B) used in the polyolefin resin composition of the present invention may be appropriately selected from resins satisfying the above formula (2) with respect to the propylene resin composition (A). That is, the refractive index of the propylene-based resin composition (A) is measured based on JIS K7105, and the resin (B) having a refractive index that matches the refractive index may be selected.

In the present invention, the resin (B) is preferably at least one selected from the group consisting of an ethylene / α-olefin copolymer (B-1) and a styrene elastomer (B-2).
In the present invention, the resin (B) can be used alone or in combination of two or more. As the resin (B), an ethylene / α-olefin copolymer (B-1) and a styrene elastomer are used. What contains both (B-2) is preferable for the reason of a diffusivity improvement. When both the ethylene / α-olefin copolymer (B-1) and the styrene elastomer (B-2) are included, the ethylene / α-olefin copolymer (B-1) and the styrene elastomer (B-2) )) (B-1) / (B-2) is preferably 90/10 to 10/90, more preferably 85/15 to 50/50. When the above range is exceeded, the diffusivity may decrease.

3. Production method of polyolefin resin composition The production method of the polyolefin resin composition of the present invention is not particularly limited, and a generally used method can be used.
As an example, a method similar to the method for producing the propylene resin composition (A) can be used, and the propylene resin composition (A) is incompatible with the propylene resin composition (A). In some cases, the resin (B), together with additives, may be added to a commonly used means such as a Henschel mixer, a super mixer, a ribbon blender, etc., and then mixed with a conventional single screw extruder, twin screw extruder, Banbury. It can be produced by melt-kneading in a temperature range of 180 to 280 ° with a mixer, a plastic bender, a roll or the like.
The order of kneading is not particularly limited, but kneading at a time is preferable for the reason of dispersibility.
Moreover, as a shape of resin (B), a granular thing with an average particle diameter of 0.1-20 micrometers is preferable since it is excellent in the balance of light transmittance and diffusibility. The average particle size means the particle size at an integrated value of 50% in the particle size distribution obtained by the laser diffraction / scattering method.
In the present invention, 50 to 90 parts by weight of the propylene resin composition (A) and 10 to 10 parts of the resin (B) with respect to 100 parts by weight of the total of the propylene resin composition (A) and the resin (B). It is preferably used in a proportion of 50 parts by weight, more preferably in a proportion of 55 to 85 parts by weight of the propylene-based resin composition (A) and in a proportion of 15 to 45 parts by weight of the resin (B). If the proportion of the propylene-based resin composition (A) exceeds 90 parts by weight, the total haze may decrease, and if the propylene-based resin composition is 50 parts by weight or less, the heat resistance may decrease.

4). Phase Separation Structure of Polyolefin Resin Composition The polyolefin resin composition of the present invention has a sea-island in which the phase separation structure is composed of a sea phase of the propylene resin composition (A) and an island phase of the resin (B). It has a structure.
This form can be observed as follows, for example.
Using an ultramicrotome (for example, Leica UC6) equipped with a diamond knife and a cryosystem, the polyolefin resin composition of the present invention is cooled to −120 ° C. and cut, and the cut mirror surface is ion-etched. Since the etching rate differs depending on the polymer type, irregularities corresponding to the fine structure are formed, and the phase structure can be observed. The sample thus treated can be observed in the dispersed phase structure with a scanning electron microscope (for example, Hitachi S800).

The polyolefin resin composition of the present invention having the above phase separation structure can be obtained from the above-described steps. However, when the kneading order and the extrusion temperature are changed, for example, when extruded at a low temperature, there is a problem in dispersibility. May not be obtained, or it may be difficult to obtain a resin composition having an excellent balance of light transmission and diffusion properties.
More simply, in the polyolefin-based resin composition of the present invention, if the total amount of the resin (A) and the resin (B) is 50% by weight or more, the polyolefin resin composition has a sea-island structure. Will be considered. That is, if the total amount of the resin (A) and the resin (B) is 50% by weight or more, the resin (A) forms the sea phase and the resin (B) forms the island phase. Is considered.

5. Light Diffusing Sheet The polyolefin resin composition of the present invention has a high total light transmittance when formed into a sheet and is excellent in light diffusibility. Therefore, it is suitable as a light diffusing sheet. In the present specification, the diffusive sheet means a sheet made of the polyolefin resin composition of the present invention and having a thickness of 0.1 to 5.0 mm. Accordingly, the sheet of the present invention includes what is commonly called a film.
When the thickness of the light diffusing sheet of the present invention is 1 mm, the total light transmittance is preferably 50% or more, more preferably 60% or more, and particularly preferably 85% or more. . The light diffusing sheet of the present invention has a total haze of preferably 50% or more, more preferably 70% or more, and particularly preferably 90% or more when the thickness is 1 mm. preferable. Total light transmittance and total haze are “total light transmittance of 50% or more and less than 60% and total haze of 50% or more” or “total light transmittance of 60% or more and total haze of 50% or more and less than 70%” When it is, it is excellent in the balance of light transmittance and diffusibility.
The total light transmittance and the total haze are values measured using a molded sheet piece in accordance with JIS K7105.
As described above, the polyolefin resin composition of the present invention and the light diffusing sheet using the same are lightweight, recyclable with polyolefin, and have an excellent balance of light transmission and diffusibility, and as a light diffusing sheet material. Useful.
Therefore, it can be preferably applied to LED lighting covers, backlight type liquid crystal panels, rear projector screens, and the like.

In the following, in order to describe the present invention more specifically and clearly, the present invention will be described in contrast to examples and comparative examples, demonstrating the rationality and significance of the requirements of the composition of the present invention. The following examples are examples of embodiments of the present invention, and the present invention is not limited to the following examples. In addition, various production conditions and evaluation result values in the following examples have meanings as preferred values of the upper limit or the lower limit in the embodiment of the present invention, and the preferred range is the above-described upper limit or lower limit value. It may be a range defined by a combination of values of the following examples or values of the examples.
In each Example and Comparative Example, the physical properties used were measured by the following method, and the propylene resin composition (A) and the resin (B) incompatible with the propylene resin composition (A) were as follows. I used something.

1. Measurement method (TREF measurement)
The TREF measurement method is as described above.
[apparatus]
(TREF part)
TREF column: 4.3 mmφ × 150 mm stainless steel column column packing material: 100 μm surface inactive glass bead heating method: aluminum heat block cooling method: Peltier element (Peltier element cooling is water-cooled)
Temperature distribution: ± 0.5 ° C
Temperature controller: Chino Corporation Digital Program Controller KP1000 (Valve Oven)
Heating method: Air bath oven measurement temperature: 140 ° C
Temperature distribution: ± 1 ° C
Valve: 6-way valve 4-way valve (sample injection part)
Injection method: Loop injection method Injection amount: Loop size 0.1ml
Inlet heating method: Aluminum heat block measurement temperature: 140 ° C
(Detection unit)
Detector: Fixed wavelength infrared detector FOXBORO MIRAN 1A
Detection wavelength: 3.42 μm
High-temperature flow cell: Micro flow cell for LC-IR Optical path length: 1.5 mm Window shape: 2φ x 4 mm long circle Temperature during measurement of synthetic sapphire window: 140 ° C
(Pump part)
Liquid feed pump: SSC-3461 pump manufactured by Senshu Kagaku Co. [Measurement conditions]
Solvent: o-dichlorobenzene (containing 0.5 mg / mL BHT)
Sample concentration: 5 mg / mL
Sample injection volume: 0.1 mL
Solvent flow rate: 1 mL / min

(Calculation of each component amount)
It calculated by the method mentioned above using TREF.

(Calculation of ethylene content)
According to the above-mentioned method, the ethylene content in the random copolymer was measured by infrared spectroscopy using a characteristic absorber of 733 cm ⁻¹ with the ethylene-propylene random copolymer whose composition was verified by ¹³ C-NMR as a reference substance. The pellets were formed into a film having a thickness of about 500 microns by press molding.

(Molecular weight distribution)
Measurement was performed by the method described above.

(MFR measurement)
MFR:
Based on JIS K7210, it measured at the temperature of 230 degreeC by the 2.16kg load.

(DSC measurement)
Melting peak temperature Tm:
Using a differential scanning calorimeter (DSC apparatus) (product name: RDC220U) manufactured by Seiko Instruments Inc., a sample of 5.0 mg is taken, held at 200 ° C. for 5 minutes, and then crystallized to 40 ° C. at a rate of 10 ° C./min. Further, the melting peak temperature when melted at a heating rate of 10 ° C./min was measured.

(2) Preparation of test pieces Various test pieces were molded by a Toshiba Machine EC-100 injection molding machine using a JIS family mold at a molding temperature of 200 ° C and a mold temperature of 40 ° C. The thicknesses of various test pieces are as described in Table-4 to Table-6.

(Tan δ peak by solid viscoelasticity measurement)
What was cut out into a strip shape of 10 mm × 18 mm × 2 mmt from a molded sheet obtained by injection molding was used as a test piece. The apparatus used was ARES manufactured by Rheometric Scientific. The frequency is 1 Hz. The measurement temperature was raised stepwise from −60 ° C., and the measurement was performed until the sample melted and became impossible to measure. The strain was performed in the range of 0.1 to 0.5%.

(density)
Based on JIS K7112, it measured at 23 degreeC. The unit is g / cm ³ .

Total light transmittance, total haze:
Using the above molded sheet piece, measurement was performed in accordance with JIS K7105.

Optical property evaluation:
Based on JIS K7105, the total light transmittance and total haze were measured for the produced 1 mm thick sheet. In addition, evaluation of the optical characteristic made the thing of the total light transmittance 50% or more and the total haze 50% or more pass, and made the other thing unacceptable by a measured value. Further, the acceptable ones were evaluated in three stages of “◎”, “◯”, and “Δ” as shown below. Among these three-level evaluations, “◎” was evaluated as the best.
A: “Total light transmittance of 85% or more and total haze of 90% or more”
○: “Total light transmittance of 60% or more and less than 85% and total haze of 70% or more” or “Total light transmittance of 85% or more and total haze of 70% or more and less than 90%”
Δ: “total light transmittance of 50% or more and less than 60% and total haze of 50% or more” or “total light transmittance of 60% or more and total haze of 50% or more and less than 70%”
×: “Total light transmittance less than 50%” or “Total haze less than 50%”

Diffusion measurement:
A variable angle photometer GC5000L (manufactured by Nippon Denshoku Industries Co., Ltd.) transmits light at various angles within a range of ± 85 ° while automatically changing the angle of the light receiving portion at 1 ° intervals with respect to the transmitted light of the sample (thickness: 1.0 mm). The strength was measured, and the diffusivity was calculated by the following formula. The larger the diffusion rate, the better the diffusibility. If it is 0.20 or more, it is good, and if it is 0.30 or more, it is particularly good.
(Diffusion rate) = [L (20) + L (70)] / [2 × L (5)]
= [T (20) / cos (20) + T (70) / cos (70)] / [2T (5) / cos (5)]
* However, L: Luminance, T: Transmittance () values are angles (radians)

2. Resin used (PP1) Propylene-ethylene block copolymer The propylene-ethylene block copolymer (PP1) used as the propylene-based resin composition (A) was produced as follows.

(I) Preparation of prepolymerized catalyst (chemical treatment of silicate)
To a 10-liter glass separable flask with a stirring blade, 3.75 liters of distilled water was added slowly followed by 2.5 kg of concentrated sulfuric acid (96%). At 50 ° C., 1 kg of montmorillonite (Menzawa Chemical Co., Ltd. Benclay SL; average particle size = 25 μm, particle size distribution = 10-60 μm) was dispersed, heated to 90 ° C., and maintained at that temperature for 6.5 hours. After cooling to 50 ° C., the slurry was filtered under reduced pressure to recover the cake. 7 liters of distilled water was added to this cake to reslurry it, and then filtered. This washing operation was performed until the pH of the washing solution (filtrate) exceeded 3.5. The collected cake was dried at 110 ° C. overnight under a nitrogen atmosphere. The weight after drying was 707 g.

(Drying silicate)
The silicate previously chemically treated was dried with a kiln dryer. Specifications and drying conditions are as follows.
Rotating cylinder: Cylindrical, inner diameter 50 mm, heating zone 550 mm (electric furnace)
Rotating speed with lifting blade: 2rpm
Tilt angle: 20/520
Silicate feed rate: 2.5 g / min Gas flow rate: Nitrogen, 96 liters / hour Countercurrent drying temperature: 200 ° C. (powder temperature)

(Preparation of catalyst)
An autoclave having an internal volume of 16 liters equipped with a stirrer and a temperature controller was sufficiently replaced with nitrogen. 200 g of dry silicate was introduced, 1160 ml of n-heptane and 840 ml of a heptane solution of triethylaluminum (0.60 M) were added and stirred at room temperature. After 1 hour, the sample was washed with n-heptane to remove impurities and by-products, and a silicate slurry was prepared to 2,000 ml. Next, 9.6 ml of a heptane solution of triisobutylaluminum (0.71 M / L) was added to the silicate slurry prepared above and reacted at 25 ° C. for 1 hour. (R) -Dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4H-azulenyl}] zirconium 2,180 mg (0.3 mM) and n-heptane 870 ml were mixed with triisobutyl. Add 33.1 ml of a heptane solution of aluminum (0.71 M) and react for 1 hour at room temperature. Add the mixture to the silicate slurry, stir for 1 hour, add n-heptane to 5,000 ml. Prepared.

(Prepolymerization / washing)
Subsequently, the temperature in the tank was raised to 40 ° C., and when the temperature was stabilized, propylene was supplied at a rate of 100 g / hour to maintain the temperature. After 4 hours, the supply of propylene was stopped and maintained for another 2 hours.
After completion of the prepolymerization, the remaining monomer was purged, stirring was stopped and the mixture was allowed to stand for about 10 minutes, and then 2,400 ml of the supernatant was obtained by decantation. Subsequently, 9.5 ml of a heptane solution of triisobutylaluminum (0.71 M / L) and 5,600 ml of n-heptane were further added, stirred at 40 ° C. for 30 minutes, allowed to stand for 10 minutes, and then the supernatant was added to 5,600 ml. Excluded. This operation was further repeated 3 times. When the component analysis of the final supernatant was performed, the concentration of the organoaluminum component was 1.23 mM / L, the Zr concentration was 8.6 × 10 ⁻⁶ g / L, and the abundance in the supernatant with respect to the charged amount was It was 0.016%. Subsequently, 170 ml of a heptane solution of triisobutylaluminum (0.71 M / L) was added, followed by drying at 45 ° C. under reduced pressure. A prepolymerized catalyst containing 2.0 g of polypropylene per 1 g of catalyst was obtained.
Using this prepolymerized catalyst, a propylene-ethylene block copolymer was produced according to the following procedure.

(Ii) First polymerization step A horizontal reactor (L / D = 6, internal volume 100 liters) having a stirring blade was sufficiently dried, and the inside was sufficiently replaced with nitrogen gas. While stirring at a rotation speed of 30 rpm in the presence of a polypropylene powder bed, 0.568 g / hr of the prepolymerized catalyst adjusted by the above method (as the amount of solid catalyst excluding the prepolymerized powder) in the upstream part of the reactor, Triisobutylaluminum was continuously fed at 15.0 mmol / hr. The monomer mixed gas is continuously reacted so that the reactor temperature is maintained at 65 ° C., the pressure is maintained at 2.1 MPaG, the ethylene / propylene molar ratio in the reactor gas phase is 0.07, and the hydrogen concentration is 100 ppm It was made to distribute | circulate in a container and vapor phase polymerization was performed. The polymer powder produced by the reaction was continuously extracted from the downstream portion of the reactor so that the amount of the powder bed in the reactor was constant. At this time, the amount of the polymer extracted when the steady state was reached was 10.0 kg / hr.
When the propylene-ethylene random copolymer component (component (K1)) obtained in the first polymerization step was analyzed, the MFR was 6.0 g / 10 min and the ethylene content was 2.2% by weight.

(Iii) Second polymerization step The propylene-ethylene copolymer extracted from the first polymerization step was continuously supplied to a horizontal reactor (L / D = 6, internal volume 100 liters) having a stirring blade. While stirring at a rotational speed of 25 rpm, the temperature of the reactor is maintained at 70 ° C., the pressure is maintained at 2.0 MPaG, and the ethylene / propylene molar ratio in the gas phase in the reactor is 0.453, and the hydrogen concentration is 330 ppm. A monomer mixed gas was continuously passed through the reactor to carry out gas phase polymerization. The polymer powder produced by the reaction was continuously extracted from the downstream portion of the reactor so that the amount of the powder bed in the reactor was constant. At this time, oxygen was supplied as an activity inhibitor so that the amount of polymer extracted was 17.9 kg / hr, and the polymerization reaction amount in the second polymerization step was controlled. The activity was 31.429 kg / g-catalyst. The propylene-ethylene random copolymer component obtained in the second polymerization step was “component (K2)”.
Various analysis results of the propylene-ethylene block copolymer (PP1, component (K)) thus obtained are shown in Table 3.
The density of PP1 is 0.886 g / cm ³ , and in the temperature-loss tangent curve obtained by solid viscoelasticity measurement for PP1, the tan δ curve has a single peak at −14 ° C. below 0 ° C. Had.

The following resins were used as resins other than PP1.
(PP2) Propylene homopolymer Novatec (registered trademark) PP MA3 (manufactured by Nippon Polypro Co., Ltd., Ziegler catalyst, MFR (JIS K7210, 230 ° C., 2.16 kg load): 11 g / 10 min)

The following were used as the resin (B) having a specific compatibility with the propylene resin composition (A).
(TPO1) ethylene butene copolymer TAFMER (registered trademark) A4050S (Mitsui Chemicals, density: 0.866, MFR (JIS K7210, 230 ° C., 2.16 kg load): 6.7 g / 10 min)
(TPO2) ethylene butene copolymer TAFMER (registered trademark) A4085 (Mitsui Chemicals, density: 0.887, MFR (JIS K7210, 230 ° C., 2.16 kg load): 6.8 g / 10 min)
(TPO3) ethylene / propylene copolymer EP07P (manufactured by JSR, density: 0.859, MFR (JIS K7210, 230 ° C., 2.16 kg load): 0.6 g / 10 min)

(PE1) Metallocene-based low density polyethylene 1:
Kernel (registered trademark) KF380 (manufactured by Nippon Polyethylene Co., Ltd., density: 0.918, MFR (JIS K7210, 190 ° C., 2.16 kg load): 4.0 g / 10 min)
(PE2) Metallocene low density polyethylene 2:
Kernel (registered trademark) KS260 (manufactured by Nippon Polyethylene Co., Ltd., density: 0.902, MFR (JIS K7210, 190 ° C., 2.16 kg load): 2.2 g / 10 min)
(PE3) Gas phase linear low density polyethylene:
Novatec (registered trademark) PP UH411 (manufactured by Nippon Polyethylene Co., Ltd., density: 0.920, MFR (JIS K7210, 190 ° C., 2.16 kg load): 0.3 g / 10 min)
(PE4) High density polyethylene:
Novatec (registered trademark) PP HB432E (manufactured by Nippon Polyethylene Co., Ltd., density: 0.957, MFR (JIS K7210, 190 ° C., 2.16 kg load): 0.3 g / 10 min)

(S-1) Styrene elastomer Dynalon (registered trademark) 4600P (manufactured by JSR, density: 0.910, MFR (JIS K7210, 230 ° C., 2.16 kg load): 5.5 g / 10 min)

Preparation of Polyolefin Resin Composition In the polyolefin resin compositions of Examples 1 to 4 and Comparative Examples 1 and 2, materials blended at the ratios described below were dry blended. The blended resin was melt extruded from a PMS30-32 extruder (manufactured by IKG) having a diameter of 30 mmΦ into a sheet having a resin temperature of 200 ° C. and a width of 300 mm. Next, the molten sheet was guided to a polishing roll (roll temperature: 60 ° C.) and solidified by cooling to produce a sheet having a thickness of 1.0 mm and a width of 300 mm. The optical characteristics were evaluated using the prepared sheet. In any case, the propylene-based resin composition (A) is used more than the propylene-based resin composition (A) and the resin (B) that is compatible with the propylene-based resin composition (A). ) Formed the sea phase, and the propylene-based resin composition (A) and the resin (B) that were compatible with each other formed the island phase. The results are shown in Table-4.

3. Examples and Comparative Examples (Example 1)
Resin (A) PP1) 60% by weight Density 0.886 (PP1 is the same hereinafter)
Resin (B) TPO1) 40 wt% Density 0.866 (TPO1 is the same hereinafter)
Resin (B) dispersed in resin (A) (average particle size 0.4 μm)
(Example 2)
Resin (A) PP1) 60% by weight
Resin (B) TPO3) 40% by weight Density 0.859 (TPO3 is the same hereinafter)
(Example 3)
Resin (A) PP1) 50% by weight Density of resin (A) 0.899
PP2) 30% by weight
Resin (B) TPO1) 20% by weight
Example 4
Resin (A) PP1) 50% by weight Density of resin (A) 0.899
PP2) 30% by weight
Resin (B) TPO3) 20% by weight

(Comparative Example 1)
Resin (A) PP1) 60% by weight
Resin (B) TPO2) 40 wt% Density 0.887 (TPO2 is the same hereinafter)
(Comparative Example 2)
Resin (A) PP1) 50% by weight Density of resin (A) 0.899
PP2) 30% by weight
Resin (B) TPO2) 20% by weight

  As is clear from Table-4, Examples 1 to 4 were prepared by blending a propylene-based composition (A), a polypropylene resin having an optimal density difference and an incompatible resin (B). While the density difference between the composition (A) and the polypropylene resin and the incompatible resin (B) is outside the specified range of the present invention, the total light transmittance is almost the same. It can be seen that the sheet is a light diffusing sheet having a high overall haze and an excellent balance between light transmittance and diffusibility.

(Examples 5 to 10, Comparative Examples 3 and 4)
Materials blended in the proportions described below were dry blended. The blended resin was melt extruded from a PMS30-32 extruder (manufactured by IKG) having a diameter of 30 mmΦ into a sheet having a resin temperature of 200 ° C. and a width of 300 mm. Next, the molten sheet was guided to a polishing roll (roll temperature: 60 ° C.) and solidified by cooling to produce a sheet having a thickness of 1.0 mm and a width of 300 mm. The optical characteristics were evaluated using the prepared sheet. In any case, the propylene-based resin composition (A) is used more than the propylene-based resin composition (A) and the resin (B) that is compatible with the propylene-based resin composition (A). ) Formed the sea phase, and the propylene-based resin composition (A) and the resin (B) that were compatible with each other formed the island phase. The results are shown in Table-5.

(Example 5)
Resin (A) PP1) 60% by weight
Resin (B) PE1) 40% by weight Density 0.918 (PE1 is the same hereinafter)
(Example 6)
Resin (A) PP1) 60% by weight
Resin (B) PE3) 40% by weight Density 0.920 (PE3 is the same hereinafter)
(Example 7)
Resin (A) PP1) 50% by weight Density of resin (A) 0.899
PP2) 30% by weight
Resin (B) PE1) 20% by weight
(Example 8)
Resin (A) PP1) 50% by weight Density of resin (A) 0.899
PP2) 30% by weight
Resin (B) PE3) 20% by weight
Resin (B) dispersed in resin (A) (average particle size 1.8 μm)
Example 9
Resin (A) PP1) 45 wt% Density of resin (A) 0.900
PP2) 30% by weight
S-1) 5% by weight
Resin (B) PE3) 20% by weight
(Example 10)
Resin (A) PP2) 80% by weight Density 0.900 (PP2 is the same hereinafter)
Resin (B) PE3) 20% by weight

(Example 11)
Resin (A) PP1) 60% by weight
Resin (B) PE2) 40% by weight
(Comparative Example 3)
Resin (A) PP1) 50% by weight
PP2) 30% by weight
Resin (B) PE2) 20% by weight
(Comparative Example 4)
Resin (A) PP2) 80% by weight
Resin (B) PE4) 20% by weight

  As is apparent from Table-5, Examples 5 to 11 were prepared by blending the propylene-based composition (A) and the incompatible resin (B) having an optimal density difference, and the propylene-based resin composition. Compared to Comparative Examples 3 and 4 in which the difference in density between (A) and the polypropylene resin and the incompatible resin (B) is outside the specified range of the present invention, the total light transmittance and the total haze are both high. It can be seen that the light diffusive sheet has an excellent balance between light transmittance and diffusibility.

(Examples 12 to 14)
Materials blended in the proportions described below were dry blended. The blended resin was melt-extruded into a sheet having a resin temperature of 230 ° C. and a width of 400 mm from a T-table single-axis sheet molding machine having a diameter of 40 mmΦ (manufactured by Plastic Giken Co., Ltd.). Next, the molten sheet was guided to a polishing roll (polishing temperature: upper 50 ° C., middle 80 ° C., lower 50 ° C.) and solidified by cooling to produce a sheet having a thickness of 2.0 mm and a width of 400 mm. Using the produced sheet, total light transmittance, total haze and diffusivity were measured. The results are shown in Table-6.

(Example 12)
Resin (A) PP1) 60% by weight
Resin (B) PE3) 40% by weight
* Same formulation as Example 6 (Example 13)
Resin (A) PP1) 50% by weight
PP2) 30% by weight
Resin (B) PE3) 20% by weight
Resin (B) dispersed in resin (A) (average particle size 1.8 μm)
* Same formulation as Example 8 (Example 14)
Resin (A) PP1) 45% by weight
PP2) 30% by weight
S-1) 5% by weight
Resin (B) TPO3) 20% by weight
* Same formulation as Example 9

  As is clear from Table-6, Examples 12 to 14 are light diffusive sheets excellent in balance of diffusivity, light transmittance, and diffusibility, and among these, Example 14 is diffusivity, light transmittance, The balance of diffusibility was particularly excellent.

As described above, when Examples 1 to 14 and Comparative Examples 1 to 4 are compared with each other from the results shown in Tables 4 to 6, the “propylene resin composition” is a specific matter of the polyolefin resin composition of the present invention. A polyolefin resin composition containing the product (A) and the propylene resin composition (A) and an incompatible resin (B), wherein the phase separation structure is a propylene resin composition (A and sea phase), sea consisting of the island phase of the resin (B) - an island structure, and the density d _B and said the and the density d _a propylene resin composition (a) resin (B) The compositions shown in Comparative Examples 1 to 4 by a method that does not satisfy the requirement of “polyolefin resin composition satisfying formula (1)” cannot be said to have a good balance between total light transmittance and total haze, and optical characteristics. Evaluation is inferior to the composition of Examples 1-14.
Compared to these comparative examples, it was confirmed that all of the polyolefin resin compositions according to the present invention have preferable optical property evaluation and good diffusivity as shown in Examples 1-14.
Therefore, the polyolefin resin composition of the present invention and the light diffusing sheet using the same are confirmed to be a light diffusing sheet having a large diffusivity and an excellent balance of light transmission and diffusibility, such as an LED lighting cover. It can be suitably used for the purpose of diffusing the point light source.

  Since the polyolefin resin composition of the present invention has an excellent balance of light transmittance and diffusibility and is useful as a light diffusive sheet, it can be suitably used for applications in which a point light source such as an LED lighting cover is diffused. In addition, the polyolefin resin composition and the light diffusive sheet of the present invention use a propylene resin composition, and thus are lightweight and recyclable.

Claims (5)

A polyolefin-based resin composition containing a propylene-based resin composition (A) and the propylene-based resin composition (A) and an incompatible resin (B),
The phase separation structure is a sea-island structure composed of the sea phase of the propylene-based resin composition (A) and the island phase of the resin (B), and the density d _{A of the} propylene-based resin composition (A) and the resin and density _{d B} of (B) is less than the following formula (1),
The propylene-based resin composition (A) is composed of 20 to 100 parts by weight of a propylene-ethylene block copolymer having the following characteristics (i) to (v) and a propylene homopolymer or a propylene-ethylene copolymer 0 to 0: A polyolefin-based resin composition comprising 80 parts by weight .
0.015 ≦ | d _A −d _B | ≦ 0.050 (1)
(I) Using a metallocene-based catalyst, 30 to 95% by weight of propylene alone or a propylene-ethylene random copolymer component (a) having an ethylene content of 7% by weight or less in the first polymerization step, and a component ( It is a propylene-ethylene block copolymer obtained by successively polymerizing 70 to 5 wt% of a propylene-ethylene random copolymer component (b) containing 3 to 20 wt% more ethylene than a).
(Ii) The melt flow rate (MFR: 230 ° C., 2.16 kg load) is in the range of 0.5 to 100 g / 10 min.
(Iii) The melting peak temperature (Tm) by differential scanning calorimetry (DSC) is in the range of 110 to 150 ° C.
(Iv) The molecular weight distribution (Mw / Mn) measured by gel permeation chromatography (GPC) is in the range of 1.5 to 4.0.
(V) In the temperature-loss tangent curve obtained by solid viscoelasticity measurement, the tan δ curve has a single peak at 0 ° C. or lower.   50 to 90 parts by weight of the propylene resin composition (A) and 10 to 50 parts by weight of the resin (B) are contained with respect to a total of 100 parts by weight of the propylene resin composition (A) and the resin (B). The polyolefin resin composition according to claim 1. Resin (B) is an ethylene / alpha-olefin copolymer (B-1) and it in claim 1 or 2, characterized in at least one selected from the group consisting of styrene elastomer (B-2) The polyolefin resin composition described. Light diffusing sheet obtained by molding the polyolefin resin composition according to any one of claims 1-3. The light diffusing sheet according to claim 4 , wherein when the thickness is 1 mm, the total light transmittance is 50% or more and the total haze is 50% or more.

Images