JP2011162650A - Polypropylene resin composition and molded product composed thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polypropylene resin composition excellent in transparency, impact resistance, and flexibility. <P>SOLUTION: The polypropylene resin composition contains a propylene polymer (A) having a melting point (Tm) of 110-175°C, a propylene polymer (B) which meets (b1) a content of a structural unit derived from propylene of 51-99 mol%, (b2) a Shore A hardness of 20-95, (b3) a density of 840-880 kg/m<SP>3</SP>, and (b4) a glass transition temperature of -50 to 0°C and has a melting point Tm of lower than 100°C or unobservable, and 0.01-2 pts.wt. [based on 100 pts.wt. sum of (A) and (B)] compound (C) which is represented by chemical structural formula (I) (wherein n is 0, 1 or 2; A is a non-hydrogen group; and R<SP>1</SP>to R<SP>10</SP>are each hydrogen, a halogen, a phenyl group, a 1-20C alkyl group, an alkenyl group, an alkoxy group or an acyl group and the hydrogen in the phenyl group, alkyl group, alkenyl group, alkoxy group or acyl group may be substituted with a halogen, and any two adjacent groups of R<SP>1</SP>to R<SP>10</SP>may be linked with each other to form a cyclic group). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polypropylene material (polypropylene resin composition) having both transparency and impact resistance, and a molded article comprising the same.

  Polypropylene material (polypropylene resin composition) is widely used as a general-purpose material having excellent performance, environmental compatibility and hygiene. In particular, compared to polyethylene, which is a similar polyolefin material, polypropylene is excellent in rigidity, transparency, and heat resistance, so it is widely applied not only to films and sheets but also to bottles and cases. In particular, clothes cases, food containers, medical instruments, stationery sheets, and the like are known as applications utilizing the advantage of transparency.

  As a technique for improving the transparency of polypropylene, a crystal structure control technique using a transparent nucleating agent is known. Organophosphate nucleating agents, sorbitol nucleating agents, etc. are common and widely used as transparent nucleating agents, but the transparency of polypropylene materials using such transparent nucleating agents is not always sufficient, For example, it does not reach polystyrene and polycarbonate resin.

  In recent years, a new transparent nucleating agent has been found, and a clearing effect of a polypropylene material which is further superior to the conventional transparent nucleating agent has been found (see Patent Document 1). Moreover, the technique which obtains the molded object which has the further outstanding transparency by using the composition which consists of such a transparent nucleating agent and a specific random polypropylene is also disclosed (refer patent document 2). However, the molded products obtained by these techniques are not sufficient in impact resistance, and applicable applications are limited.

  By the way, as a technique for improving impact resistance, which is a drawback of polypropylene materials, a technique for blending a specific elastomer is known. For example, Patent Document 3 discloses a composition in which a transparent nucleating agent and an elastomer having a specific refractive index are blended with a polypropylene material, and Patent Document 4 discloses a propylene homopolymer and a propylene-ethylene copolymer. A composition in which a specific transparent nucleating agent is blended with a polypropylene material composed of a polymer is disclosed. Here, the polypropylene material is specified by the relationship between the component amount eluted in a specific temperature range, the ethylene content in the component eluted in a specific temperature range, and the intrinsic viscosity of the component eluted in a specific temperature range. .

  Further, Patent Document 5 maintains the transparency of the molded article by blending the transparent nucleating agent described in Patent Documents 1 and 2 and a specific ethylene / α-olefin copolymer with polypropylene material. However, a technique for improving impact resistance is disclosed.

Special table 2007-534827 gazette JP 2009-120281 A Japanese Patent Laid-Open No. 10-045970 JP 2000-248147 A JP 2009-155422 A

In order to apply a polypropylene material having both environmental compatibility and hygiene to applications that require transparency, a technology that achieves both transparency and impact resistance at a high level is desired.

  Therefore, an object of the present invention is to provide a technique for imparting impact resistance and flexibility without deteriorating the transparency at the same time as compared with a polypropylene material based on the prior art. .

  As a result of intensive studies in view of such circumstances, the present inventors have found that the above problem can be solved by adopting the configuration of the following invention.

  That is, the present invention relates to the following.

[1] A propylene polymer (A) having a melting point (Tm) of 110 to 175 ° C. and a propylene polymer (B) satisfying the following (b1) to (b4) and having a melting point (Tm) of less than 100 ° C. or not observed And a compound (C) represented by the following chemical structural formula (I):
A polypropylene resin composition comprising 0.01 to 2 parts by weight of the compound (C) with respect to a total of 100 parts by weight of the propylene polymer (A) and the propylene polymer (B).

(B1) The content of structural units derived from propylene is 51 to 99 mol%.
(B2) Shore A hardness is 20 to 95
(B3) Density is 840-880 kg / m ³
(B4) Glass transition temperature is −50 to 0 ° C.

(In the formula (I), n is 0, 1 or 2, A is a non-hydrogen group, R ^{1 to} R ¹⁰
Are each independently a hydrogen atom, a halogen atom, a phenyl group or an alkyl group, alkenyl group, alkoxy group, or acyl group having 1 to 20 carbon atoms, a phenyl group, an alkyl group, an alkenyl group, an alkoxy group, and The hydrogen atom in the acyl group may be substituted with a halogen atom, and any two adjacent groups may form a cyclic group with each other).

[2] The propylene polymer (A) and the propylene polymer (B) do not have a phase separation structure, and further have a melting point (Tm) (° C.) in the entire composition and a propylene-derived structural unit in the entire composition. The polypropylene resin composition as described in [1] above, wherein the content (X _C3 ) (mol%) of the resin satisfies the following formula (II):

Tm ≧ 3.75 × X _C3 -205 (II)
(In Formula (II), Tm is 140 ° C. or higher.)
[3] The propylene polymer (B) is propylene, ethylene, and α-carbon having 4 to 20 carbon atoms.
The polypropylene resin composition according to the above [1] or [2], which is obtained from an olefin.

  [4] The polypropylene resin composition as described in [1] above, further comprising an elastomer (D) having a glass transition temperature (Tg) lower than that of the propylene polymer (B).

  [5] The polypropylene resin composition as described in [4] above, wherein the propylene polymer (B) is obtained from propylene, ethylene and an α-olefin having 4 to 20 carbon atoms.

  [6] The molded product of the present invention is composed of the polypropylene resin composition according to any one of [1] to [5].

  The polypropylene resin composition excellent in transparency, impact resistance and flexibility obtained by the present invention can be widely applied to transparent molded bodies that have been difficult to apply with conventional polypropylene materials.

  Hereinafter, the polypropylene resin composition of the present invention and a molded article comprising the same will be described in detail.

  Since the polypropylene resin composition of the present invention contains the propylene polymer (A), the propylene polymer (B) and the compound (C), transparency and impact resistance are excellent in a well-balanced manner. Specifically, since it contains the propylene polymer (A) and the propylene polymer (B), it is excellent in impact resistance and flexibility, and the transparency improvement effect by the compound (C) is sufficient. Demonstrated.

  Specific embodiments of the polypropylene resin composition of the present invention will be described below.

≪First polypropylene resin composition≫
The first polypropylene resin composition of the present invention comprises a propylene polymer (A), a propylene polymer (B) and a compound (C).

  First, the components constituting the first polypropylene resin composition will be described in detail.

<Propylene polymer (A)>
The propylene polymer (A) used in the present invention has a melting point (Tm) obtained by differential scanning calorimeter (DSC) measurement of 110 to 175 ° C. A propylene polymer (A) may be used independently, or may use 2 or more types together.

  As the propylene polymer (A), a known polypropylene material can be used. For example, homopropylene, propylene and one or more propylene selected from the group consisting of propylene and ethylene or α-olefin (excluding propylene). Random copolymers, propylene block copolymers, and mixtures thereof. As α-olefin (excluding propylene), 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene Examples thereof include α-olefins having 4 to 20 carbon atoms such as 1-octadecene and 1-eicocene.

  These polypropylene materials can be appropriately selected according to the application and purpose, but homopolypropylene and propylene random copolymers are preferable in order to achieve the improvement of transparency, which is the main object of the present invention. A propylene random copolymer having a content of 90 to 98 mol%, more preferably 92 to 97 mol% is more preferable.

  With respect to the stereoregularity of the propylene polymer (A), both an isotactic structure and a syndiotactic structure can be used as long as they are well compatible with the propylene polymer (B) described later.

  When the propylene polymer (A) is an isotactic propylene polymer, the isotactic pentad fraction (mmmm fraction) measured by NMR method is 90% or more, preferably 95% or more. Is preferred.

Here, the isotactic pentad fraction indicates the abundance ratio of isotactic chains in pentad units in a molecular chain measured using ¹³ C-NMR, and five consecutive propylene monomer units. The fraction of propylene monomer units at the center of the meso-bonded chain. Specifically, it is a value calculated as a fraction of the mmmm peak in the total absorption peak in the methyl carbon region observed in the ¹³ C-NMR spectrum.

  In addition, this isotactic pentad fraction (mmmm fraction) can be calculated | required by the method of Unexamined-Japanese-Patent No. 2007-186664, for example.

  On the other hand, when the propylene polymer (A) is a syndiotactic propylene polymer, the syndiotactic pentad fraction (rrrr) measured by NMR method is 85% or more, preferably 90% or more. Is preferred.

  In addition, this syndiotactic pentad fraction (rrrr) can be calculated | required by the method of Unexamined-Japanese-Patent No. 2008-169316, for example.

  The propylene polymer (A) has a melting point (Tm) obtained by differential scanning calorimeter (DSC) measurement of 110 to 175 ° C., preferably 115 to 170 ° C., more preferably 140 to 170 ° C., and further analysis. The heat of fusion (ΔH) is usually 30 to 150 J / g, preferably 40 to 100 J / g, more preferably 50 to 80 J / g.

  When the characteristics of the propylene polymer (A) are within this range, practically sufficient performance is exhibited in moldability, heat resistance and the like.

  Further, the melt flow rate (MFR; ASTM D1238, 230 ° C., under 2.16 kg load) of the propylene polymer (A) can be appropriately selected according to the purpose and use, but is usually 0.01 to 1000 g / 10 min. Preferably it is 0.1-200 g / 10min, More preferably, it is 0.1-100 g / 10min. In order to adjust to such an MFR value, it is also possible to increase the MFR by adding an organic peroxide to the propylene polymer (A) having a low MFR and melt-mixing it at a high temperature.

  The catalyst used for obtaining the propylene polymer (A) is not particularly limited, and a known catalyst can be used. For example, a Ziegler-Natta catalyst or a metallocene catalyst formed by combining a titanium compound and organic aluminum can be used.

<Propylene polymer (B)>
The propylene polymer (B) used in the present invention satisfies the following (b1) to (b4), and the melting point (Tm) is less than 100 ° C. or is not observed in the differential scanning calorimeter (DSC) measurement. A propylene polymer (B) may be used independently, or may use 2 or more types together.

(B1) The content of propylene-derived structural units (propylene content) is 51 to 99 mol%, preferably 55 to 89 mol%, more preferably 60 to 89 mol%, still more preferably 60 to 85 mol%.
(B2) Shore A hardness measured according to ASTM D-2240 is 20 to 95, preferably 25 to 90, more preferably 40 to 85.
(B3) A density measured according to ASTM D-1505 is 840 to 880 kg / m ³ , preferably 850 to 875 kg / m ³ , more preferably 855 to 875 kg / m ^3.
(B4) The glass transition temperature obtained by differential scanning calorimetry (DSC) measurement is −50 to 0 ° C., preferably −50 to −10 ° C., more preferably −50 to −20 ° C. More preferably, it is −40 ° C. or higher.

  Such a propylene polymer (B) is a polymer that is thermodynamically compatible with the propylene polymer (A), is flexible, and does not easily become brittle even at low temperatures. Here, “thermodynamically compatible” means that the propylene polymer (A) and the propylene polymer (B) are mixed at a melting point or higher of both components (for example, when melt kneaded or mixed in a solvent). Means that no phase separation occurs when the solvent is removed). When the melting point of the propylene polymer (B) is not observed, no phase separation occurs when the propylene polymer (A) and the propylene polymer (B) are mixed at a temperature equal to or higher than the melting point of the propylene polymer (A). Means that.

  The melting point (Tm) of the propylene polymer (B) is less than 100 ° C, preferably 30 to 80 ° C, more preferably 30 to 70 ° C, still more preferably 30 to 60 ° C, or is not observed. In the propylene polymer (B), the fact that the melting point is not observed means that the crystallinity of the propylene polymer (B) is almost zero.

  Further, the propylene polymer (B) in which the melting point is not observed (crystallinity is almost zero) can achieve the object of the present invention (coexistence of transparency and impact resistance). The molded body using (B) may have a strong surface stickiness. From the viewpoint of suppressing the stickiness of the surface of the molded body, the melting point (Tm) of the propylene polymer (B) is less than 100 ° C, preferably 30 to 80 ° C, more preferably 30 to 70 ° C, and further preferably 30 to 60 ° C. It is desirable to be at ° C.

  In addition, when the melting point of the propylene polymer (B) used in the present invention is in such a range, it may flow at room temperature or around 40 ° C., and handling as pellets may be difficult. In such a case, the propylene polymer (A) can be handled as pellets that maintain a stable shape by blending the propylene polymer (A) with a small amount, for example, 5 to 30 wt%, in the propylene polymer (B).

  The melting point of the propylene polymer (B) having a low crystallinity as used in the present invention is easily affected by the solid structure forming conditions (for example, cooling temperature, curing time after forming the solid structure) of the propylene polymer (B). Is defined as a value measured by the following method.

  In the DSC curve obtained when the specimen after condition adjustment for 72 hours or more at 23 ° C. ± 2 ° C. was cooled to −40 ° C. or lower and measured at a heating rate of 10 ° C./min, the melting peak Observe Tm (A). Here, the case where the melting point is not observed is a case where a crystal melting peak having a heat of crystal melting of 1 J / g or more is not observed in the range of −40 to 200 ° C. in the differential scanning calorimeter (DSC) measurement.

  The propylene polymer (B) satisfying the requirement (b1) ensures that the propylene polymer (A) and the propylene polymer (B) are thermodynamically compatible. At the same time, the propylene polymer (B) of the present invention satisfies the requirement (b1), so that sufficient flexibility can be imparted to improve the impact resistance of the polypropylene material.

  When the propylene polymer (B) satisfies the requirements (b2) and (b3), it means that the propylene polymer (B) has a low crystallinity (crystallinity) and is a flexible material.

  The Shore A hardness is obtained by heating and melting the propylene polymer (B) at 190 to 230 ° C. and press-molding it at a cooling temperature of 15 to 25 ° C. in an environment of 23 ° C. ± 2 ° C. It is a value obtained by storing the scale for 72 hours or longer and then using a type A measuring instrument and immediately reading the scale after touching the needle. The density is a value measured with a test specimen prepared by the same method as the Shore A hardness measurement procedure.

  The fact that the propylene polymer (B) satisfies the requirement (b4) means that the propylene polymer (B) has an ability to improve the impact resistance of the propylene polymer (A) even at a low temperature.

Examples of the propylene polymer (B) include a propylene homopolymer, a propylene copolymer of one or more selected from the group consisting of propylene, ethylene, and α-olefin (excluding propylene). α-olefin (excluding propylene) is 1-
4 carbon atoms such as butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene ˜20 α-olefins. As the propylene polymer (B),
A copolymer obtained from propylene, ethylene and an α-olefin having 4 to 20 carbon atoms is preferably used.

As a more preferable form of the propylene polymer (B) satisfying all the requirements (b1) to (b4), the following propylene / ethylene / α-olefin random copolymer may be mentioned. Such a propylene / ethylene / α-olefin random copolymer satisfies any of the following (b5), (b6-1) or (b6-2), (b7) and (b8), preferably ( All of b5), (b6-1) or (b6-2), (b7) and (b8) are satisfied.

  (B5) 51 to 90 mol%, preferably 55 to 89 mol% of propylene-derived structural units, 7 to 24 mol%, preferably 8 to 20 mol% of ethylene-derived structural units, and α having 4 to 20 carbon atoms -Containing 3 to 25 mol%, preferably 3 to 25 mol% of structural units derived from olefin The total is 100 mol%).

  (B6-1) When the propylene polymer (A) used in the present invention is an isotactic propylene polymer, the isotactic triad fraction (mm) calculated by NMR is 60 to 99.9%, preferably 85. ˜99.9%, more preferably 85-99.9%.

  (B6-2) When the propylene polymer (A) used in the present invention is a syndiotactic propylene polymer, the syndiotactic triad fraction (rr) calculated by NMR is 60% or more, preferably 70% or more, More preferably, it is 75% or more.

Here, regarding the isotactic triad fraction (mm), for example, International Publication 2
It is calculated | required by the method described in 21st page 7th line to 26th page 6th line of the 004-087775 pamphlet, About syndiotactic triad fraction (rr), For example, the method as described in Unexamined-Japanese-Patent No. 2008-169316 Can be obtained.

  (B7) The B value defined by the following formula (1) is 0.8 to 1.3, preferably 0.9 to 1.2, and more preferably 0.9 to 1.1.

In the formula, M _OE represents the mole fraction of the total of the chain of propylene and ethylene and the chain of α-olefin and ethylene having 4 or more carbon atoms with respect to all dyads, and M 2 _O represents propylene and 4 carbon atoms.
The total of the mole fractions of the above α-olefins is represented, and M _E represents the mole fraction of ethylene.

  (B8) The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) measured by gel permeation chromatography (GPC) is 1.2 to 3.5, preferably 1.4 to 3.0, more preferably 1.6 to 2.6.

  The melt flow rate (MFR; ASTM D1238, 230 ° C., under a load of 2.16 kg) of the propylene polymer (B) can be appropriately selected according to the purpose and use, but is usually 0.01 to 1000 g / 10 minutes, preferably 0.1 to 200 g / 10 min, more preferably 0.1 to 100 g / 10 min. In order to adjust to such an MFR value, it is also possible to increase the MFR by adding an organic peroxide to the propylene polymer (B) having a low MFR and melt-mixing it at a high temperature.

  The propylene polymer (B) can also be graft-modified with a polar monomer.

  A propylene polymer (B) can be manufactured by the method described, for example in the international publication 2004/087775 pamphlet.

<Compound (C)>
Examples of the compound (C) used in the present invention include compounds represented by the formula (1) described in JP-A-2009-120721 (see paragraphs [0020] to [0024], [0027] etc.). More specifically, compounds represented by the following general structural formula (I) can be mentioned. A compound (C) may be used independently or may use 2 or more types together.

  In the structural formula (I), n is 0, 1 or 2.

A represents a non-hydrogen group. The non-hydrogen group A includes —CH ₃ , —CH ₂ CH ₃ , —CH ₂ CH ₂ CH ₃ , —CH ₂ CH ₂ CH ₂ CH ₃ , —CH ₂ CH═CH ₂ , —CH (CH ₃ ) CH═ CH _2, -CH ₂ C
_{H-X-CH 2 -X '} , - CH 2 CH-X''- CH 2 -CH 3, -CH 2 CH-X''' -
CH ₂ OH, or —CH—OH—CH—OH—CH ₂ —OH. Here, X, X ′, X ″ and X ′ ″ are halogenated hydrocarbon groups such as halogen atoms or halogenated alkyl groups. Preferred are a fluorine atom, a chlorine atom or a bromine atom, or a halogenated alkyl group containing a fluorine atom, a chlorine atom or a bromine atom.

R ^{1 to} R ¹⁰ are each independently a hydrogen atom, a halogen atom, a phenyl group or a carbon number of 1
˜20 alkyl groups, alkenyl groups, alkoxy groups, or acyl groups, and the hydrogen atom in the phenyl group, alkyl group, alkenyl group, alkoxy group, and acyl group may be substituted with a halogen atom. As the halogen atom, a fluorine atom is preferable.

In R ^{1 to} R ¹⁰ , any two adjacent groups may form a cyclic group with each other.

From the viewpoint of transparency, more preferably, in Structural Formula (I), n is 0, 1 or 2, and R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁹ and R ¹⁰ Are each a hydrogen atom, and R ³ , R ⁸ and A are each an alkyl group having 1 to 20 carbon atoms.

  Specific examples of the compound (C) include Mirad NX8000 (manufactured by Milliken & Company) available as a commercial product.

<Other ingredients>
In the first polypropylene resin composition, one or more kinds of nucleating agents other than the compound (C) may be used in combination as long as the object of the present invention (coexistence of transparency and impact resistance) is not impaired. . The nucleating agent used here is not particularly limited, and a known nucleating agent can be used. For example, the nucleating agent is dibenzylidene sorbitol nucleating agent, phosphate salt nucleating agent, rosin nucleating agent, Examples include benzoic acid metal salt-based nucleating agents.

  In addition to the above-mentioned other nucleating agents, the first polypropylene resin composition has a weather-resistant stabilizer, a heat-resistant stabilizer, as long as the object of the present invention (coexistence of transparency and impact resistance) is not impaired. Even if additives such as antistatic agents, anti-slip agents, anti-blocking agents, anti-fogging agents, lubricants, pigments, dyes, plasticizers, anti-aging agents, hydrochloric acid absorbents, antioxidants are blended as necessary Good.

  Next, a 1st polypropylene resin composition and a molded object which consists of this are demonstrated.

  The first polypropylene resin composition of the present invention comprises a propylene polymer (A), a propylene polymer (B) and a compound (C). Other components may be used as necessary.

  The blending ratio of the propylene polymer (A) and the propylene polymer (B) can be arbitrarily set according to the purpose, but the propylene polymer (A) is preferably 50 to 99 parts by weight, more preferably 50 to 95 weights. Part of the propylene polymer (B), preferably 1 to 50 parts by weight, more preferably 5 to 50 parts by weight. Here, the total of the propylene polymer (A) and the propylene polymer (B) is 100 parts by weight. When the blending ratio of the propylene polymer (A) and the propylene polymer (B) is in the above range, a suitable molded body having both rigidity and heat resistance in addition to transparency and impact resistance can be obtained.

  Moreover, the compounding quantity of a compound (C) is 0.01-2 weight part with respect to a total of 100 weight part of a propylene polymer (A) and a propylene polymer (B), Preferably it is 0.05-1 weight part, More preferably, it is 0.05-0.8 weight part. When the compounding amount of the compound (C) is within this range, the transparency is optimized, and at the same time, the elution and bleeding out of the compound (C) from the molded product can be suppressed.

  In addition, the compounding quantity of nucleating agents other than a compound (C) is 0.01-0.15 weight part with respect to a total of 100 weight part of a propylene polymer (A) and a propylene polymer (B). It is desirable. The blending amount of other additives is desirably 0.01 to 2 parts by weight with respect to 100 parts by weight as a total of the propylene polymer (A) and the propylene polymer (B).

  The first polypropylene resin composition is characterized in that the propylene polymer (A) and the propylene polymer (B) are thermodynamically compatible, that is, have no phase separation structure. Specifically, the thermodynamic compatibility results from the elastomer (soft polymer component) even when the structure of the polypropylene resin composition is observed with a microscope (for example, a transmission electron microscope (TEM)). This means that no phase separation structure is observed. More specifically, it can be defined that the propylene polymer (B) does not have a dispersed phase of 0.1 μm or more, preferably 0.05 μm or more, in the matrix formed by the propylene polymer (A). Such a first polypropylene resin composition is particularly excellent in transparency.

  Next, the preferable form of a 1st polypropylene resin composition is demonstrated.

In a preferred form of the first polypropylene resin composition, the propylene content in the resin component comprising the propylene polymer (A) and the propylene polymer (B) is 76 to 99.5 mol%, preferably 80 to 99 mol%, More preferably, it is 85-96 mol%. In this specification, this propylene content is also called content _Xc3 (mol%) of the structural unit derived from propylene in the whole composition. The other constituent components mainly correspond to the content of constituent units derived from ethylene or α-olefin (excluding propylene) in the propylene polymer (A) and the propylene polymer (B).

  Moreover, in the preferable form of a 1st polypropylene resin composition, melting | fusing point (Tm) obtained by the differential scanning calorimeter (DSC) measurement derived from a propylene polymer (A) component is 110-175 degreeC, Preferably it is 115-170 degreeC, More preferably, it is 135-170 degreeC, More preferably, it is 140-170 degreeC. In this specification, this melting point (Tm) is also referred to as the melting point (Tm) (° C.) in the entire composition.

  Furthermore, what satisfy | fills following formula (II) is especially preferable.

Tm ≧ 3.75 × X _C3 -205 (II)
In the formula (II), Tm represents a melting point (° C.) in the entire composition and is 140 ° C. or higher. X _C3
Represents the content (mol%) of propylene-derived constituent units in the total composition.

  The first polypropylene resin composition satisfying the formula (II) has a high propylene content in the entire composition and a high melting point in the entire composition, and therefore has excellent heat resistance in addition to excellent transparency and impact resistance. ing.

On the other hand, in the prior art, a random copolymer of propylene and ethylene or α-olefin having a high comonomer content (that is, having a low propylene content) is generally used to improve impact resistance without reducing the transparency of the material. However, in this case, a decrease in the melting point of the polypropylene material is inevitable with a decrease in the propylene content. Therefore, there was room for improvement in heat resistance.

  The melt flow rate (MFR; ASTM D1238, 230 ° C., under a load of 2.16 kg) of the first polypropylene resin composition can be appropriately selected depending on the purpose and application, but is usually 0.01 to 1000 g / 10 minutes, preferably Is 0.1 to 200 g / 10 min, more preferably 0.1 to 100 g / 10 min.

  A suitable method for obtaining the first polypropylene resin composition includes a method of melt kneading the above components using a known kneader. For example, after mixing by mixing into a Henschel mixer, super mixer, ribbon blender, etc., it is obtained by melt-kneading at a temperature range of 170 to 320 ° C. with a normal single screw extruder, twin screw extruder, Banbury mixer, roll, etc. be able to.

  By the way, as a technique for improving impact resistance, which is a drawback of polypropylene materials, a technique for blending a specific elastomer is known. For example, in patent document 5, the transparent nucleating agent described in the previous patent documents 1 and 2 and the specific ethylene-alpha-olefin copolymer are mix | blended with the polypropylene material. However, all these techniques are common in that an elastomer compounded for the purpose of improving impact resistance is dispersed in a polypropylene phase to form a phase separation structure. In such a case, a decrease in transparency is inevitable unless the density and refractive index of the elastomer and polypropylene (generally, the density and refractive index of these elastomers are correlated) are not completely matched. Also, from the viewpoint of industrial convenience, it is difficult to select the same refractive index as the polypropylene material used from the commercially available limited elastomers. Even if effective, there is a problem that the transparency of other polypropylene materials is greatly impaired.

In general, the refractive index of polypropylene is about 1.49 to 1.52, but the density of the ethylene / α-olefin copolymer having the same refractive index is about 890 to 920 kg / m ^3. Such an ethylene / α-olefin copolymer is not necessarily flexible, and the impact resistance, flexibility, and ductility of polypropylene cannot be effectively improved (with a small addition amount).

  In contrast, in the first polypropylene resin composition, the propylene polymer (A) and the propylene polymer (B) do not have a phase separation structure. For this reason, while being excellent in impact resistance and a softness | flexibility, the transparency improvement effect by a compound (C) can fully be exhibited.

≪Second polypropylene resin composition≫
As a technique to which the polypropylene resin composition of the present invention is applied, a technique of blending an elastomer (D) having a glass transition temperature lower than that of the propylene polymer (B) of the present invention into the polypropylene resin composition of the present invention can be exemplified. Such a second polypropylene resin composition of the present invention contains a propylene polymer (A), a propylene polymer (B) and a compound (C), and further contains an elastomer (D).

  First, the components constituting the second polypropylene resin composition will be described in detail.

  The propylene polymer (A), the propylene polymer (B) and the compound (C) are the same as those described in the first polypropylene resin composition.

<Elastomer (D)>
The elastomer (D) has a lower glass transition temperature than the propylene polymer (B).
The elastomer (D) may be used alone or in combination of two or more. By using such an elastomer (D), it is possible to further improve impact resistance while maintaining transparency.

  Although there will be no restriction | limiting in particular if a glass transition temperature is lower than a propylene polymer (B), Usually, it is lower than -50 degreeC and is -150 degreeC or more. Moreover, it is preferably −100 ° C. or higher.

  There are no particular restrictions on the type of elastomer having such a low glass transition temperature. For example, ethylene / α-olefin random copolymer, styrene / butadiene rubber and its hydride, ethylene / vinyl acetate copolymer, ethylene Examples thereof include acrylic acid copolymers and ethylene / methyl methacrylate copolymers.

  Other components (other nucleating agents and additives other than the compound (C)) that may be contained in the polypropylene resin composition are the same as those described in the first polypropylene resin composition.

  Next, a 2nd polypropylene resin composition and a molded object which consists of this are demonstrated.

  The 2nd polypropylene resin composition of this invention is comprised using a propylene polymer (A), a propylene polymer (B), a compound (C), and an elastomer (D). Other components may be used as necessary.

  The blending ratio of the propylene polymer (A) and the propylene polymer (B) can be arbitrarily set according to the purpose, but the propylene polymer (A) is preferably 50 to 99 parts by weight, more preferably 50 to 95 weights. Part of the propylene polymer (B), preferably 1 to 50 parts by weight, more preferably 5 to 50 parts by weight. Here, the total of the propylene polymer (A) and the propylene polymer (B) is 100 parts by weight. When the blending ratio of the propylene polymer (A) and the propylene polymer (B) is in the above range, a suitable molded body having both rigidity and heat resistance in addition to transparency and impact resistance can be obtained.

  The total amount of the propylene polymer (A) and the propylene polymer (B) is usually 60 to 99 parts by weight, preferably 70 to 99 parts by weight, and the content of the elastomer (D) is usually 1 to 40 parts by weight, The amount is preferably 1 to 30 parts by weight. Here, the total of the propylene polymer (A), the propylene polymer (B) and the elastomer (D) is 100 parts by weight. When the content of the elastomer (D) is within this range, the impact resistance can be further improved while maintaining transparency.

  Moreover, the compounding quantity of a compound (C) is 0.01-2 weight part with respect to a total of 100 weight part of a propylene polymer (A), a propylene polymer (B), and an elastomer (D), Preferably 0.05- 1 part by weight, more preferably 0.05 to 0.8 part by weight. When the compounding amount of the compound (C) is within this range, the transparency is optimized, and at the same time, the elution and bleeding out of the compound (C) from the molded product can be suppressed.

  In addition, the compounding quantity of nucleating agents other than a compound (C) is 0.01-0.15 with respect to a total of 100 weight part of a propylene polymer (A), a propylene polymer (B), and an elastomer (D). A part by weight is desirable. The blending amount of the other additives is desirably 0.01 to 2 parts by weight with respect to 100 parts by weight in total of the propylene polymer (A), the propylene polymer (B), and the elastomer (D).

The melt flow rate (MFR; ASTM D1238, 230 ° C., under 2.16 kg load) of the second polypropylene resin composition can be appropriately selected according to the purpose and application,
Usually 0.01 to 1000 g / 10 min, preferably 0.1 to 200 g / 10 min, more preferably 0.1 to 100 g / 10 min.

  In the second polypropylene resin composition, a phase separation structure is usually observed by the elastomer (D). However, since the refractive index of the polypropylene resin composition can be arbitrarily adjusted by arbitrarily setting the ratio of the propylene polymer (A) and the propylene polymer (B), the refractive index with the elastomer (D) can be easily matched. It becomes possible. For this reason, the impact resistance (especially under low temperature) of a polypropylene resin composition can further be improved, suppressing the fall of transparency to the minimum.

<Molded body>
The molded product of the present invention comprises the above-described polypropylene resin composition of the present invention.

  The polypropylene resin composition of the present invention can be processed by a known molding method such as a blow molding method, an injection molding method, a press molding method, an extrusion molding method, an inflation molding method, and is stretched during or after the processing. Is also possible.

  The use of the molded body comprising the polypropylene resin composition of the present invention is not particularly limited. For example, automobile interior parts, automobile exterior parts, home appliance parts, civil engineering / building material parts, packaging materials, daily / industrial materials, It can be suitably used for medical materials, clothing materials, optical materials, toys, leisure goods, etc., and above all, it is used for various bottles, cups, sheets, films used for food containers and food packaging moldings, and for daily and industrial materials. It can be preferably used for medical cases, cosmetic cases, and syringes that are medical instruments.

  Hereinafter, the present invention will be described by way of examples.

1. Test method for evaluating properties and physical properties of polypropylene resin composition and molded article comprising the same (1) Transparency About square plate (thickness 2 mm) molded by the method described in Examples or Comparative Examples, Nippon Denshoku Industries Co., Ltd. The diffuse transmitted light amount and the total transmitted light amount were measured using a digital turbidimeter “NDH-2000” manufactured by Co., Ltd. and a C light source, and the internal haze and the total light transmittance were calculated by the following equations.

Haze (%) = 100 × (diffuse transmitted light amount) / (total transmitted light amount)
Total light transmittance (%) = 100 × (total transmitted light amount) / (incident light amount)
(2) Impact resistance Izod impact strengths at 0 ° C. and 23 ° C. were determined according to ASTM D256 using an injection specimen (a test piece with a notch having a thickness of 3 mm) molded by the method described in Examples or Comparative Examples.

(3) Tensile test Using an injection specimen (ASTM-IV shape test piece having a thickness of 3 mm) molded by the method described in the examples or comparative examples, in accordance with ASTM D638, tensile speed = 50 mm / min
The yield stress (YS), the stress at break (TS), the elongation at break (EL), and the tensile modulus (YM) were analyzed.

(4) Melting | fusing point in all compositions About the shape | molded square plate, it measured with the temperature increase rate of 20 degrees C / min from 23 degreeC using the DSC measuring apparatus made from Perkin Elmer, and it is the maximum heat among the melting peaks observed. The one corresponding to the flow rate was taken as the melting point of the entire composition.

(5) Propylene content in all compositions The propylene content was calculated | required by the FT-IR measurement about the polypropylene resin composition obtained by the method as described in an Example or a comparative example. Specifically, it was determined from the peak derived from the propylene unit (wave number 1150 cm ⁻¹ ) and the absorbance derived from other comonomer.

(6) Presence / absence of phase separation structure Sections collected from the core portion of the molded square plate were stained with ruthenic acid and observed with a transmission electron microscope (TEM) to confirm the presence or absence of the phase separation structure.

  In addition, although it did not confirm about the molded object obtained by all the Examples and the comparative example, about what can be judged that a phase-separation structure is not confirmed, it is N.N. T.A. Marked with (Not Tested).

2. Raw materials used in Examples and Comparative Examples (1) Propylene polymer (A)
table. Two types of polypropylene (PP-1, PP-2) shown in 1 were used. These physical property values were measured by the following methods.

[Melting point]
The DSC curve obtained by the following procedure was analyzed and obtained using a DSC measuring apparatus manufactured by PerkinElmer.

Method for DSC measurement of PP-1 and PP-2 (i) After heating up to 200 ° C. at 100 ° C./min and holding at 200 ° C. for 5 minutes, (ii) −20 at 20 ° C./min Then, the temperature was lowered to 200C, and then (iii) the temperature was raised to 200 ° C at 20 ° C / min. The endothermic curve obtained in (iii) was analyzed and determined.

[Propylene content and comonomer content]
^It was determined by analysis of ¹³ C-NMR spectrum.

[Stereoregularity (mmmm)]
^It was determined by analysis of ¹³ C-NMR spectrum.

[Melt flow rate (MFR)]
Based on ASTM D1238, measurement was performed at 230 ° C. and a load of 2.16 kg.

(2) Propylene polymer (B)
table. The propylene / ethylene / 1-butene copolymer (PBER) shown in 2 was used. These physical property values were measured by the following methods.

[Propylene content and comonomer content]
^It was determined by analysis of ¹³ C-NMR spectrum.

[Shore A hardness]
After heating for 5 minutes using a hydraulic hot press molding machine set at 190 ° C., pressurization was performed for 2 minutes and immediately cooled in a cooling tank set at 20 ° C. for 4 minutes to produce a 3 mm thick press sheet. This was stored for 72 hours in an environment of 23 ° C. ± 2 ° C., and the scale was read immediately after contact with the needle using an A-type measuring instrument (according to ASTM D-2240).

  In press molding, a 100 μm PET film (manufactured by Toray, Lumirror) was used as a release film.

[density]
A sample cut out from a press sheet produced under the same conditions as those used for Shore A hardness measurement was measured by a method based on ASTM D-1505.

[Melting point, glass transition temperature]
The DSC curve obtained by the following procedure was analyzed and obtained using a DSC measuring apparatus manufactured by PerkinElmer.

DSC measurement method of propylene polymer (B) After carrying out state adjustment for 72 hours or more at 23 degreeC ± 2 degreeC about the sample cut out from the press sheet produced on the same conditions as what was used for Shore A hardness measurement, After cooling to −40 ° C., a DSC curve was obtained by measuring at a heating rate of 10 ° C./min.

[Molecular weight distribution (Mw / Mn)]
GPC (gel permeation chromatography) was used as an orthodichlorobenzene solvent (mobile phase) and measured at a column temperature of 140 ° C. (polystyrene conversion, Mw: weight average molecular weight, Mn: number average molecular weight). Specifically, the molecular weight distribution (Mw / Mn) was measured as follows using a gel permeation chromatograph Alliance GPC-2000 model manufactured by Waters. The separation columns are two TSKgel GNH6-HT and two TSKgel GNH6-HTL.The column size is 7.5 mm in diameter and 300 mm in length, the column temperature is 140 ° C, and the mobile phase is Using o-dichlorobenzene (Wako Pure Chemical Industries) and 0.025% by weight of BHT (Takeda Pharmaceutical) as an antioxidant, it was moved at 1.0 ml / min, the sample concentration was 15 mg / 10 ml, and the sample injection volume was 500 A microliter was used, and a differential refractometer was used as a detector. The standard polystyrene used was manufactured by Tosoh Corporation for molecular weights of Mw <1000 and Mw> 4 × 106, and that of Pressure Chemical Co. was used for 1000 ≦ Mw ≦ 4 × 106.

[Stereoregularity (mm)]
It was determined by analysis of ¹³ C-NMR spectrum according to the method described in WO 2004-087775, page 21, line 7 to page 26, line 6.

[B value]
According to the method described in JP 2007-186664 A, it was determined by analysis of ¹³ C-NMR spectrum.

[Melt flow rate (MFR)]
Based on ASTM D1238, measurement was performed at 230 ° C. and a load of 2.16 kg.

Such a propylene / ethylene / 1-butene copolymer can be prepared by using, for example, diphenylmethylene (3-tert-butyl-diethylene) prepared by the method described in JP-A-2007-186664 as a polymerization catalyst / co-catalyst. 5-ethylcyclopentadienyl) (2,7-di-tert-butylfluorenyl) zirconium dichloride / methylaluminoxane (manufactured by Tosoh Finechem, 0.3 mmol in terms of aluminum) and raw materials ethylene, propylene, 1-butene can be obtained by polymerization in hexane solution using a continuous polymerization facility.

(3) Compound (C)
In the examples, D-glycero-L-glo-nonitol, 7,8,9, -trideoxy-3,5: 45-bis-O-[(R-propylphenyl) methylene] (commercial product) manufactured by Milliken Japan Ltd. Name: Millad NX8000J).

  In the comparative examples, bis (3,4 dimethylbenzylidene) sorbitol (trade name: Millad 3998) manufactured by Milliken Japan Co., Ltd. and bis (methylbenzylidene) sorbitol (trade name: Gelall manufactured by Shin Nippon Chemical Co., Ltd.) are used. MD (Gel all MD)) was used.

(4) Elastomer (D) having a low glass transition temperature
(A) Ethylene / 1-butene random copolymer (EBR)
Tuffmer A-4090 (MFR (190 ° C., 2.16 kg load) = 3.6 g / 10 min, density = 893 kg / m ³ , glass transition temperature = −52 ° C.) manufactured by Mitsui Chemicals, Inc. was used.

(B) Hydrogenated styrene / ethylene / butylene block copolymer (SEBS)
Tuftec H-1062 manufactured by Asahi Kasei Co., Ltd. (styrene content = 18 wt%, MFR (230 ° C., 2.16 kg load) = 4.5 g / 10 min, Shore A hardness = 68, vinyl bond amount = about 40%, glass transition Temperature = −59 ° C.) was used.

[Glass-transition temperature]
Using a DSC measuring device manufactured by Seiko Instruments Inc., the DSC curve obtained by the following procedure was analyzed and determined.

About the raw material (pellet) used for the DSC measuring method of the elastomer (D), after cooling to −100 ° C., the heating rate is 10 ° C./mi
A DSC curve was obtained as measured by n.

[Example 1]
First, a fine powder (powder) propylene polymer (A) (PP-1), a compound (C) (Mirad NX8000), and a hindered phenol-based antioxidant (made by Ciba) as a heat stabilizer. , Trade name: Irganox 1010) and phosphorus-based antioxidant (Ciba, trade name: Irgaphos 168), each of which is blended with 500 ppm each, using a single screw extruder with an inner diameter of 40 mm, and a resin temperature of about 250 to While maintaining at 260 ° C., melt kneading was performed to prepare a kneaded body composed of the propylene polymer (A) and the compound (C).

  Next, PBER which is a propylene polymer (B) is blended with this kneaded body, and melt-kneaded using a single screw extruder having an inner diameter of 40 mm as described above while maintaining the resin temperature at about 250 to 260 ° C. A product was obtained (see Table 3-1).

  In addition, the compounding quantity of a propylene polymer (A), a propylene polymer (B), and a compound (C) is Table. It is as 3-1.

  The obtained polypropylene resin composition was injection-molded under the conditions of a molding temperature of 240 ° C., a mold temperature of 40 ° C., and a holding time of 20 seconds, a 2 mm-thick square plate, and a specimen for evaluation of impact resistance test and tensile test. Was molded. Table shows the composition of the polypropylene resin composition and the properties and physical properties of the molding composed of the composition. Shown in 3-1.

[Examples 2-6, 9-10]
The types and blending amounts of the propylene polymer (A), the propylene polymer (B) and the compound (C) are shown in Table. A polypropylene resin composition was obtained in the same manner as in Example 1 except that it was changed as in 3-1.

  The obtained polypropylene resin composition was injection-molded under the same conditions as in Example 1 to mold a 2 mm-thick square plate and a specimen for evaluation of impact resistance test and tensile test. Table shows the composition of the polypropylene resin composition and the properties and physical properties of the molding composed of the composition. Shown in 3-1.

[Examples 7 to 8]
First, a fine powder (powder) propylene polymer (A) (PP-1), a compound (C) (Mirad NX8000), and a hindered phenol-based antioxidant (made by Ciba) as a heat stabilizer. , Trade name: Irganox 1010) and phosphorus-based antioxidant (Ciba, trade name: Irgaphos 168), each of which is blended with 500 ppm each, using a single screw extruder with an inner diameter of 40 mm, and a resin temperature of about 250 to While maintaining at 260 ° C., melt kneading was performed to prepare a kneaded body composed of the propylene polymer (A) and the compound (C).

  Next, PBER which is a propylene polymer (B) and elastomer (D) are blended into this kneaded body, and melted while maintaining the resin temperature at about 250 to 260 ° C. using a single screw extruder having an inner diameter of 40 mm in the same manner as described above. A polypropylene resin composition was obtained by kneading (see Table 3-1).

  In addition, the compounding quantity of a propylene polymer (A), a propylene polymer (B), a compound (C), and an elastomer (D) is Table. It is as 3-1.

The obtained polypropylene resin composition was injection-molded under the same conditions as in Example 1 to mold a 2 mm-thick square plate and a specimen for evaluation of impact resistance test and tensile test. Table shows the composition of the polypropylene resin composition and the properties and physical properties of the molding composed of the composition. Shown in 3-1.

[Comparative Example 1]
Fine powder (powder) propylene polymer (A) (PP-1), compound (C) (Mirad NX8000), and hindered phenol antioxidant as a heat stabilizer (manufactured by Ciba) Name: Irganox 1010) and phosphorus-based antioxidant (Ciba, trade name: Irgaphos 168) were each blended in an amount of 500 ppm each, and the resin temperature was about 250 to 260 ° C. using a single screw extruder with an inner diameter of 40 mm. The kneaded body consisting of the propylene polymer (A) and the compound (C) was prepared by keeping melted and kneaded.

  In addition, the compounding quantity of a propylene polymer (A) and a compound (C) is Table. It is as 3-2.

  The obtained polypropylene resin composition was injection-molded under conditions of a molding temperature of 240 ° C., a mold temperature of 40 ° C., and a holding time of 20 seconds, a 2 mm-thick square plate, and a specimen for impact resistance test and tensile test evaluation. Was molded. Table shows the composition of the polypropylene resin composition and the properties and physical properties of the molding composed of the composition. Shown in 3-2.

[Comparative Examples 2 to 8]
Table shows the types and amounts of ingredients used. A polypropylene resin composition was obtained in the same manner as in Comparative Example 1 except that the composition was changed as in 3-2.

  The obtained polypropylene resin composition was injection-molded under the same conditions as in Example 1 to mold a 2 mm-thick square plate and a specimen for evaluation of impact resistance test and tensile test. Table shows the composition of the polypropylene resin composition and the properties and physical properties of the molding composed of the composition. Shown in 3-2.

[Comparative Example 9]
First, a fine powder (powder) propylene polymer (A) (PP-1), a compound (C) (Mirad NX8000), and a hindered phenol-based antioxidant (made by Ciba) as a heat stabilizer. , Trade name: Irganox 1010) and phosphorus-based antioxidant (Ciba, trade name: Irgaphos 168), each of which is blended with 500 ppm each, using a single screw extruder with an inner diameter of 40 mm, and a resin temperature of about 250 to While maintaining at 260 ° C., melt kneading was performed to prepare a kneaded body composed of the propylene polymer (A) and the compound (C).

  Next, an elastomer (D) was blended into this kneaded body, and melt-kneaded while maintaining the resin temperature at about 250 to 260 ° C. using a single screw extruder having an inner diameter of 40 mm as described above to obtain a polypropylene resin composition ( Table 3-3).

  In addition, the compounding quantity of a propylene polymer (A), a compound (C), and an elastomer (D) is Table. It is as 3-3.

  The obtained polypropylene resin composition was injection-molded under conditions of a molding temperature of 240 ° C., a mold temperature of 40 ° C., and a holding time of 20 seconds, a 2 mm-thick square plate, and a specimen for impact resistance test and tensile test evaluation. Was molded. Table shows the composition of the polypropylene resin composition and the properties and physical properties of the molding composed of the composition. Shown in 3-3.

[Comparative Examples 10-12]
Table shows the types and amounts of ingredients used. A polypropylene resin composition was obtained in the same manner as in Comparative Example 9, except that the procedure was changed as in 3-3.

  The obtained polypropylene resin composition was injection-molded under the same conditions as in Example 1 to mold a 2 mm-thick square plate and a specimen for evaluation of impact resistance test and tensile test. Table shows the composition of the polypropylene resin composition and the properties and physical properties of the molding composed of the composition. Shown in 3-3.

  table. In 3-1, 3-2 and 3-3, N.B. represents no destruction (semi-destruction), and N.T. represents no observation.

  table. As shown in the results of Examples 3-1, it can be seen that the polypropylene resin composition of the present invention has superior transparency and good impact resistance as compared with conventional polypropylene materials. In particular, very excellent transparency is exhibited in a region where the compounding amount of the compound (C) of the present invention is relatively large.

  In contrast, the polypropylene resin compositions shown in Comparative Examples 1 to 3 and 6 have excellent transparency similar to the polypropylene resin composition of the present invention, but have poor impact resistance. Moreover, although the physical properties of the polypropylene resin composition using the conventional transparent nucleating agent are reflected in Comparative Examples 4, 5, 7, and 8, the polypropylene resin composition of the present invention or the polypropylenes of Comparative Examples 1 to 3 are reflected. The transparency is inferior to that of the resin composition, and it can be presumed that excellent transparency does not appear even if the propylene polymer (B) is added thereto. The blending amount of the clear nucleating agent in the polypropylene resin composition using the conventional clear nucleating agent is optimally around 0.15 parts by weight, and even if the blending amount of the clear nucleating agent is increased further, improvement in transparency cannot be expected. On the contrary, it is known that the transparency is lowered by the transparent nucleating agent becoming an impurity.

Moreover, although the physical properties of the polypropylene resin composition which consists of another elastomer (D) are reflected in Comparative Examples 9-12 in addition to a propylene polymer (A) and a compound (C), compared with this. The first embodiment of the present invention reflected in Examples 1 to 6, and further comprising a propylene polymer (A), a propylene polymer (B), a compound (C) and another elastomer (D) It can be seen that the second embodiment of the present invention reflected in Examples 7 to 10 has an excellent balance between transparency and impact resistance.

  The polypropylene resin composition of the present invention exhibits excellent impact resistance and good rigidity in addition to transparency that cannot be achieved by conventional polypropylene materials. The molded product made of the polypropylene resin composition of the present invention has characteristics such as good heat resistance and low specific gravity in addition to its excellent transparency, and it is an alternative to polystyrene materials with poor heat resistance and polycarbonate with high specific gravity. Application as a material can also be expected.

Claims (6)

A propylene polymer (A) having a melting point (Tm) of 110 to 175 ° C, a propylene polymer (B) satisfying the following (b1) to (b4) and having a melting point (Tm) of less than 100 ° C or not observed, and Consisting of compound (C) represented by chemical structural formula (I),
A polypropylene resin composition comprising 0.01 to 2 parts by weight of the compound (C) with respect to a total of 100 parts by weight of the propylene polymer (A) and the propylene polymer (B).
(B1) The content of structural units derived from propylene is 51 to 99 mol%.
(B2) Shore A hardness is 20 to 95
(B3) Density is 840-880 kg / m ³
(B4) Glass transition temperature is −50 to 0 ° C.

(In the formula (I), n is 0, 1 or 2, A is a non-hydrogen group, R ^{1 to} R ¹⁰
Are each independently a hydrogen atom, a halogen atom, a phenyl group or an alkyl group, alkenyl group, alkoxy group, or acyl group having 1 to 20 carbon atoms, a phenyl group, an alkyl group, an alkenyl group, an alkoxy group, and The hydrogen atom in the acyl group may be substituted with a halogen atom, and any two adjacent groups may form a cyclic group with each other). The propylene polymer (A) and the propylene polymer (B) do not have a phase separation structure. Further, the melting point (Tm) (° C.) in the entire composition and the content of structural units derived from propylene in the entire composition ( The polypropylene resin composition according to claim 1, wherein X _C3 ) (mol%) satisfies the following formula (II).
Tm ≧ 3.75 × X _C3 -205 (II)
(In Formula (II), Tm is 140 ° C. or higher.)   The polypropylene resin composition according to claim 1 or 2, wherein the propylene polymer (B) is obtained from propylene, ethylene, and an α-olefin having 4 to 20 carbon atoms.   The polypropylene resin composition according to claim 1, further comprising an elastomer (D) having a glass transition temperature (Tg) lower than that of the propylene polymer (B).   The polypropylene resin composition according to claim 4, wherein the propylene polymer (B) is obtained from propylene, ethylene, and an α-olefin having 4 to 20 carbon atoms.   The molded object which consists of a polypropylene resin composition of any one of Claims 1-5.