Polypropylene resin composition and molded article obtained therefrom

Abstract

To provide a resin composition having small anisotropy of a molding shrinkage factor and a molding.SOLUTION: A polypropylene-based resin composition contains 85-99.5 wt.% of a component (A) satisfying conditions (A-1) to (A-2), and 0.5-15 wt.% of a component (B) satisfying specific conditions (B-1) to (B-3). Condition (A-1): the component (A) is a propylene homopolymer having a specific MFR. Condition (A-2): the component (A) shows a peak at a specific melting peak temperature. Condition (B-1): the component (B) is a propylene-α-olefin random copolymer, and a content of the α-olefin is 0.1-5 wt.%. Condition (B-2): a melt flow rate of the component (B) is within a specific range. Condition (B-3): the component (B) shows a peak at a specific melting peak temperature.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polypropylene-based resin composition and a molded article obtained therefrom. More specifically, the present invention relates to a polypropylene-based resin composition that provides a molded article having excellent rigidity and heat resistance and small anisotropy in the molding shrinkage rate, and a molded article obtained from this resin composition.

Background Art

[0002] Molded articles obtained by molding polypropylene resin compositions are being increasingly used in various fields such as automotive parts and home appliance parts due to their excellent moldability and physical properties.

[0003] However, with the expansion of the applications of polypropylene resin compositions, the sizes of the parts to which they are applied tend to become larger. When the size of a part becomes larger, problems such as deformation and warping in large parts occur, and thus an effective method for suppressing these problems is required. It has been found that such deformation and warping phenomena are caused by the anisotropy in the shrinkage rate during molding, and a method for further reducing the anisotropy in the molding shrinkage rate is required. In addition, as the size increases, the weight of the parts increases, and thus a method for suppressing the anisotropy in the shrinkage rate of lightweight polypropylene-based resin compositions is also required.

[0004] As a method for suppressing the deformation and warping of a molded article, a method of combining a specific polypropylene-based resin composition and an inorganic filler is known. For example, a method of suppressing the rigidity and the anisotropy in the molding shrinkage rate by combining an inorganic filler such as talc has been disclosed (for example, Patent Documents 1 and 3). In addition, a method of similarly suppressing the rigidity and the anisotropy in the molding shrinkage rate by combining wollastonite as an inorganic filler has been disclosed (for example, Patent Document 2). However, in the method of suppressing the anisotropy in the shrinkage rate by adding a filler, the density of the polypropylene-based resin composition increases, and it cannot be said that weight reduction has been achieved.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2012-229303 [Patent Document 2] Japanese Unexamined Patent Application Publication No. 2015-127405 [Patent Document 3] Japanese Unexamined Patent Application Publication No. 2017-019975 [Summary of the Invention] [Problems to be Solved by the Invention]

[0006] The present invention aims to solve problems not achieved by the above prior art, and provides a polypropylene-based resin composition that gives a molded article excellent in rigidity and having a small anisotropy in molding shrinkage rate in molded articles used for automotive parts, home appliance parts, etc., and a molded article obtained from this resin composition. [Means for Solving the Problems]

[0007] That is, as a result of intensive studies to solve the above problems, the present invention has found that a polypropylene-based resin composition obtained by blending a specific propylene homopolymer with a specific ethylene-α-olefin random copolymer at a specific ratio, and a molded article using the same as a raw material can solve the above problems, and based on these findings, the present invention has been completed.

[0008] That is, according to the first invention of the present invention, there is provided a polypropylene-based resin composition characterized by containing 85 to 99.5% by weight of component (A) satisfying the following conditions (A-1) to (A-2) and 0.5 to 15% by weight of component (B) satisfying the following conditions (B-1) to (B-3) (however, the total of component (A) and component (B) is 100% by weight). Condition (A-1): Component (A) is a propylene homopolymer having a melt flow rate (MFR, 230 ° C., 2.16 kg load) in the range of 0.5 to 100 g / 10 minutes. Condition (A-2): Component (A) shows a peak of the melting peak temperature (Tm) in the range of 160 to 175 °C in the measurement by the DSC method. Condition (B-1): Component (B) is a propylene-α-olefin random copolymer (wherein the α-olefin is an α-olefin having 2 to 8 carbon atoms (excluding 3 carbon atoms)), and the content of the α-olefin is 0.1 to 5% by weight (wherein the total of propylene and α-olefin in component (B) is 100% by weight). Condition (B-2): The melt flow rate (MFR, 230 °C, 2.16 kg load) of component (B) is in the range of 0.5 to 100 g / 10 min. Condition (B-3): Component (B) shows a peak of the melting peak temperature (Tm) in the range of 110 °C or higher and less than 160 °C in the measurement by the DSC method.

[0009] Further, according to the second invention of the present invention, there is provided a polypropylene resin composition containing 0.01 to 0.25 parts by weight of a nucleating agent (C) with respect to 100 parts by weight of the polypropylene resin composition in the first invention.

[0010] Further, according to the third invention of the present invention, there is provided a molded article obtained from the polypropylene resin composition of the first or second invention.

Effects of the Invention

[0011] The polypropylene resin composition of the present invention and the molded article made from the same have high rigidity and small anisotropy of shrinkage rate, and thus can be suitably used for a wide range of applications such as automotive parts and household electric appliance parts.

Modes for Carrying Out the Invention

[0012] The present invention relates to a polypropylene resin composition characterized by containing 85 to 99.5% by weight of a specific component (A) and 0.5 to 15% by weight of a specific component (B), preferably a polypropylene resin composition characterized by containing 0.01 to 0.2 parts by weight of a specific component (C) with respect to 100 parts by weight of the polypropylene resin composition, and a molded article formed by molding the same.

[0013] The details of each item of the polypropylene-based resin composition, its production method, and the molded article formed therefrom of the present invention will be described below.

[0014] [1] Constituent components of the polypropylene-based resin composition The polypropylene-based resin composition of the present invention contains 85 to 99.5% by weight of component (A) that satisfies the conditions (A-1) to (A-2) described below, and 0.5 to 15% by weight of component (B) that satisfies the conditions (B-1) to (B-3) described below (however, the total of component (A) and component (B) is 100% by weight). Preferably, it is in the range of 90 to 99.5% by weight of component (A) and 0.5 to 10% by weight of component (B), more preferably 92 to 99% by weight of component (A) and 1 to 8% by weight of component (B), and still more preferably 94 to 96% by weight of component (A) and 4 to 6% by weight of component (B). If the amount of component (B) is less than 0.5% by weight, the anisotropy of shrinkage increases, and if the amount of component (B) exceeds 15% by weight, there is a concern that the rigidity and heat distortion temperature (HDT) will decrease. By setting the above range, it becomes possible to obtain the polypropylene-based resin composition of the present invention that can reduce the shrinkage anisotropy while maintaining a higher rigidity and heat distortion temperature (HDT).

[0015] (1) Component (A) Component (A) used in the present invention is a propylene homopolymer that satisfies the conditions (A-1) to (A-2) described below.

[0016] (1-1) Condition (A-1): Melt flow rate (MFR) The melt flow rate (hereinafter sometimes abbreviated as MFR) of component (A) used in the present invention needs to be in the range of 0.5 to 100 g / 10 min, preferably 3 to 80 g / 10 min, more preferably 5 to 60 g / 10 min, still more preferably 15 to 55 g / 10 min, most preferably 25 to 50 g / 10 min, and particularly preferably 30 to 45 g / 10 min. By setting the MFR in the range of 0.5 to 100 g / 10 min, the polypropylene-based resin composition of the present invention has sufficient moldability (fluidity), and the generation of burrs in the molded article formed by molding the polypropylene-based resin composition can be suppressed. That is, when the MFR is less than 0.5 g / 10 min, the moldability (fluidity) may decrease, and when the MFR exceeds 100 g / 10 min, there is a risk of burr generation during molding. In addition, in this specification, the MFR is a value measured in accordance with JIS K7210 at a test temperature of 230 °C and a load of 2.16 kg. The MFR of component (A) can be easily adjusted by changing the type of catalyst, polymerization temperature, and pressure used during production, or as a general method, by adding a chain transfer agent such as hydrogen during polymerization and adjusting the addition amount.

[0017] (1-2) Condition (A-2): Melting peak temperature (Tm) Component (A) used in the present invention must have a melting peak temperature (hereinafter sometimes abbreviated as Tm) measured by the DSC (differential scanning calorimetry) method within the range of 160°C to 175°C, preferably within the range of 162°C to 170°C, and more preferably within the range of 163°C to 168°C. By setting the peak of the melting peak temperature (Tm) within this range, the heat distortion temperature (hereinafter sometimes abbreviated as HDT) and impact strength of the polypropylene resin composition of the present invention and the molded article formed therefrom can be made to be in a good range. That is, when the melting peak temperature is 160°C or higher, the HDT of the polypropylene resin composition of the present invention and the molded article formed therefrom increases. On the other hand, when the melting peak temperature (Tm) is 175°C or lower, the impact strength and the like can be improved. Further, when the melting peak temperature (Tm) is less than 160°C, the HDT of the polypropylene resin composition of the present invention and the molded article formed therefrom tends to decrease. On the other hand, when the melting peak temperature (Tm) exceeds 175°C, there is a risk that the impact strength and the like will decrease. In addition, in this specification, the melting peak temperature (Tm) was measured using a differential scanning calorimeter (for example, DSC6200 type manufactured by Seiko Instruments Inc.), taking 5.0 mg of the sample, holding it at 200°C for 5 minutes, then crystallizing it at a temperature drop rate of 10°C / min to 40°C, and further melting it at a temperature increase rate of 10°C / min. Moreover, the control of the melting peak temperature (Tm) of component (A) can be adjusted, for example, by selecting the type of catalyst used in the production of component (A).

[0018] (1-3) Density Component (A) used in the present invention preferably has a density of 0.86 to 0.92 g / cm 3 , more preferably 0.863 to 0.915 g / cm 3 , and even more preferably 0.865 to 0.91 g / cm 3 within the range. By setting the density within such a range, it is possible to make both the heat distortion temperature and the impact strength good in the polypropylene resin composition of the present invention and the molded article made from it as a raw material. That is, when the density is 0.86 g / cm 3If it is less than this value, in the polypropylene-based resin composition of the present invention and the molded article using the same as a raw material, the heat distortion temperature tends to decrease. On the other hand, if the density is more than 0.92 g / cm 3 exceeds this value, the impact strength may decrease.

[0019] (2) Component (B) Component (B) used in the present invention is a propylene-α-olefin random copolymer that satisfies the following conditions (B-1) to (B-3).

[0020] (2-1) Condition (B-1): α-olefin content Component (B) used in the present invention is a propylene-α-olefin random copolymer. When the total content of propylene and α-olefin in the propylene-α-olefin random copolymer is 100% by weight, the content of α-olefin needs to be in the range of 0.1 to 5% by weight. Further, the α-olefin is an α-olefin having 2 to 8 carbon atoms (excluding 3 carbon atoms). The content of the α-olefin is preferably 0.2 to 4.5% by weight, more preferably 0.25 to 4% by weight, and particularly preferably 0.3 to 3.5% by weight. When the content of the α-olefin is within the above range, in the polypropylene-based resin composition of the present invention and the molded article using the same as a raw material, it is possible to make the HDT and impact strength good. That is, when the content of the α-olefin is less than 0.1% by weight, the impact strength tends to decrease, and when the content exceeds 5% by weight, the heat distortion temperature (HDT) may deteriorate. In addition, in order to control the α-olefin content within a predetermined range, the amount ratio of propylene and α-olefin supplied to the polymerization tank may be appropriately adjusted during the production of component (B). The relationship between the supply ratio and the α-olefin content in the obtained propylene-α-olefin random copolymer is a technical matter well known to those skilled in the art. For example, when using a metallocene catalyst, it varies depending on the type, but by adjusting the supply ratio, component (B) having the required α-olefin content can be produced.

[0021] Examples of the α-olefins having 2 to 8 carbon atoms excluding 3 carbon atoms (propylene) used for component (B) include ethylene, 1-butene, 2-methyl-1-propene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene, 2-ethyl-1-butene, 2,3-dimethyl-1-butene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 3,3-dimethyl-1-butene, 1-heptene, methyl-1-hexene, dimethyl-1-pentene, ethyl-1-pentene, trimethyl-1-butene, 1-octene, and the like. In addition, the comonomer, which is an α-olefin having 2 to 8 carbon atoms excluding 3 carbon atoms (propylene) copolymerized with propylene, may be used alone or in combination of two or more.

[0022] Specific examples of the propylene-α-olefin random copolymer as component (B) include binary copolymers such as propylene-ethylene random copolymer, propylene-1-butene random copolymer, propylene-1-pentene random copolymer, propylene-1-hexene random copolymer, propylene-1-octene random copolymer, and ternary copolymers such as propylene-ethylene-1-butene random copolymer, propylene-ethylene-1-hexene random copolymer. Among them, propylene-ethylene random copolymer, propylene-ethylene-1-butene random copolymer, etc. are preferable, and propylene-ethylene random copolymer, which has an excellent balance of physical properties and is easily available, is particularly preferable.

[0023] (2-2) Condition (B-2): Melt flow rate (MFR) The melt flow rate of component (B) used in the present invention needs to be in the range of 0.5 to 100 g / 10 min, preferably in the range of 3 to 80 g / 10 min, more preferably in the range of 5 to 50 g / 10 min. By setting the MFR in the range of 0.5 to 100 g / 10 min, the polypropylene-based resin composition of the present invention has sufficient moldability (fluidity), and the generation of burrs in the molded article formed by molding the polypropylene-based resin composition can be suppressed. That is, when the MFR is less than 0.5 g / 10 min, the moldability (fluidity) may decrease, and when the MFR exceeds 100 g / 10 min, there is a risk of burr generation during molding. The MFR of component (B) can be easily adjusted by changing the type of catalyst, polymerization temperature, and pressure used during production, or, as a general method, by adding a chain transfer agent such as hydrogen during polymerization and adjusting the addition amount.

[0024] (2-3) Condition (B-3) Melting peak temperature (Tm) Component (B) used in the present invention needs to show a peak of the melting peak temperature measured by the DSC (differential scanning calorimeter) method in the range of 110°C or higher and less than 160°C, preferably in the range of 115°C to 159°C, more preferably in the range of 120°C to 157°C, still more preferably in the range of 125°C to 157°C, and particularly preferably in the range of 130°C to 155°C. By showing the peak of Tm in this range, the HDT and impact strength of the polypropylene-based resin composition of the present invention and the molded article formed by molding it can be made in a good range. That is, when Tm is 110°C or higher, the HDT of the polypropylene-based resin composition of the present invention and the molded article formed by molding it increases. On the other hand, when Tm is less than 160°C, the impact strength and the like can be improved. Also, when Tm is less than 110°C, the HDT of the polypropylene resin composition of the present invention and the molded article formed by molding it tends to decrease. On the other hand, when Tm is 160°C or higher, there is a risk that the impact strength and the like may decrease. In addition, the control of Tm can be achieved by appropriately adjusting the amount ratio of propylene to α-olefin supplied to the polymerization tank during the production of component (B). To control Tm, for example, to be 110°C or higher and less than 160°C, although it also depends on the type of catalyst used, by adjusting the α-olefin content to be generally 0.1 to 5% by weight, component (B) having a desired Tm can be produced.

[0025] (2-4) Density The density of component (B) used in the present invention is preferably 0.86 to 0.92 g / cm 3 , more preferably 0.863 to 0.915 g / cm 3 , still more preferably 0.865 to 0.91 g / cm 3 within the range. By setting the density within such a range, in the polypropylene-based resin composition of the present invention and the molded article made from it, both the heat distortion temperature and the impact strength can be made good. That is, when the density is less than 0.86 g / cm 3 , in the polypropylene-based resin composition of the present invention and the molded article made from it, the heat distortion temperature tends to decrease. On the other hand, when the density exceeds 0.92 g / cm 3 , the impact strength may decrease.

[0026] (3) Production methods of component (A) and component (B) The production methods of component (A) and component (B) are not particularly limited as long as polymers satisfying conditions (A-1) to (A-2) and conditions (B-1) to (B-3) can be obtained, and can be produced by known production methods. The catalysts used to obtain component (A) and component (B) used in the present invention are not particularly limited, and known catalysts can be used. For example, so-called Ziegler-Natta catalysts (described in, for example, "Polypropylene Handbook" (first edition, first printing issued on May 15, 1998), etc.) combining titanium compounds and organoaluminum, or metallocene catalysts (described in, for example, JP-A-5-295022, etc.) can be used.

[0027] In the production of component (B) particularly used in the present invention, it is preferable to use a metallocene catalyst. That is, it is preferable that the propylene-α-olefin random copolymer (B) used in the present invention is a metallocene-based random copolymer.

[0028] The polymerization process used to obtain component (A) and component (B) used in the present invention is not particularly limited, and known polymerization processes can be used. For example, slurry polymerization method, bulk polymerization method, gas-phase polymerization method, etc. can be used. Also, either batch polymerization method or continuous polymerization method can be used, and if desired, a multi-stage continuous polymerization method such as two-stage and three-stage can also be used. Further, it can also be produced by mechanically melt-kneading two or more propylene-based polymers. Moreover, various polypropylene-based resins that can be used as component (A) and component (B) are commercially available from many companies. For example, as products that can be used as component (A), Novatec series manufactured by Japan Polypropylene Corporation can be mentioned, and as products that can be used as component (B), Wintec series manufactured by Japan Polypropylene Corporation, etc. can be mentioned. It is also possible to purchase and use products having desired physical properties from these commercially available products.

[0029] (4) Nucleating agent (C) The polypropylene-based resin composition of the present invention preferably contains 0.01 to 0.25 parts by weight of a nucleating agent (C) (hereinafter, may be simply described as component (C)) based on 100 parts by weight of the polypropylene-based resin composition. Also, the blending amount of component (C) based on 100 parts by weight of the polypropylene-based resin composition is preferably in the range of 0.03 to 0.23 parts by weight, more preferably 0.05 to 0.22 parts by weight, and still more preferably 0.08 to 0.21 parts by weight. By setting the blending amount of the component (C) in the range of 0.01 to 0.25 parts by weight, an effect of increasing the heat distortion temperature (hereinafter, may be abbreviated as HDT) of the molded body can be obtained. That is, if the blending amount of the component (C) is less than 0.01 part by weight, there is a possibility that the effect of increasing the heat distortion temperature of the molded body cannot be obtained. On the other hand, if the blending amount of the component (C) exceeds 0.25 parts by weight, the anisotropy of the shrinkage rate may increase.

[0030] Component (C) that can be used in the present invention preferably includes a nucleating agent (a) represented by the following formula (1), a nucleating agent (b) represented by the following formula (2), a nucleating agent (c) represented by the following formula (3), a nucleating agent (d) composed of an aromatic carboxylic acid metal salt, a nucleating agent (e) represented by the following formula (4), and the like. Note that component (C) may be used alone or in combination of two or more kinds.

[0031] The nucleating agent (a) is an aminobenzene-based compound represented by the following general formula (1). [Chemical formula] (In the formula, R 1 , R 2 and R 3 each independently represent an unsubstituted or substituted hydrocarbon group.)

[0032] Specific examples of the compound having this unsubstituted or substituted hydrocarbon group include various compounds shown below. The nucleating agent used in the present invention basically has the performance that can be appropriately achieved if it has the form of the compound of the above formula (1). The various compounds having an unsubstituted or substituted hydrocarbon group depend on which reaction components are selected when synthesizing the compound represented by the formula (1) used in the present invention, and slightly affect the reaction yield of the compound of the formula (1), but act equivalently as a nucleating agent, and the following can be specifically exemplified.

[0033] For the formula (1) compound in which at least one of the groups R 1 , R 2 and R 3 is represented by a branched alkyl group having 3 to 20 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms that is unsubstituted or substituted by one or more alkyl groups having 1 to 20 carbon atoms is preferred.

[0034] Also, the groups R 1 , R 2 and R 3which are, independently of each other, an isopropyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1,1-dimethylpropyl group, a 1-ethylpropyl group, a tert-butylmethyl group, a cyclopropyl group, a 3-methylcyclopropyl group, a 2,2,3,3-tetramethylcyclopropyl group, a cyclopentyl group, a cyclopentylmethyl group, a 2-cyclopentylethyl group, a cyclohexyl group, a cyclohexylmethyl group, a 2-cyclohexylethyl group, a 4-tert-butylcyclohexyl group, a (4-methylcyclohexyl)methyl group, a functional group represented by the following formulas (1-1) to (1-3), an α-cyclohexylbenzyl group, a 3-methylbenzyl group, a 3,4-dimethoxybenzyl group, a 4-biphenylmethyl group, a 2-naphthylmethyl group, an m-tolyl group, an m-methoxyphenyl group, a p-tolyl group, a 4-ethylphenyl group, a 4-isopropylphenyl group, a 4-tert-butylphenyl group, a 2,3-dimethylphenyl group, a 2,6-dimethylphenyl group, a 2,4-dimethylphenyl group, a 3,4-dimethylphenyl group, a 3,5-dimethylphenyl group, a 3,5-di-tert-butylphenyl group, a 2,4,6-trimethylphenyl group or a 3,5-di-tert-butyl-4-hydroxyphenyl group, and the compound of the formula (1) is more preferable.

Chemical formula

Chemical formula

Chemical formula

[0035] Specifically, as the compound represented by the formula (1), 1,3,5-tris[2,2-dimethylpropionylamino]benzene, 1,3,5-tris[cyclohexylcarbonylamino]benzene, 1,3,5-tris[4-methylbenzoylamino]benzene, 1,3,5-tris[3,4-dimethylbenzoylamino]benzene, 1,3,5-tris[3,5-dimethylbenzoylamino]benzene, 1,3,5-tris[cyclopentanecarbonylamino]benzene, 1,3,5-tris[1-adamantanecarbonylamino]benzene, 1,3,5-tris[2-methylpropionylamino]benzene, 1,3,5-tris[3,3-dimethylbutyrylamino]benzene, 1,3,5-tris[2-ethylbutyrylamino]benzene, 1,3,5-tris[2,2-dimethylbutyrylamino]benzene, 1,3,5-tris[2-cyclohexyl-acetylamino]benzene, 1,3,5-tris[3-cyclohexyl-propionylamino]benzene, 1,3,5-tris[4-cyclohexyl-butyrylamino]benzene, 1,3,5-tris[5-cyclohexyl-valeroylamino]benzene, 1-isobutyrylamino-3,5-bis[pivaloylamino]benzene, 2,2-dimethylbutyrylamino-3,5-bis[pivaloylamino]benzene, 3,3-dimethylbutyrylamino-3,5-bis[pivaloylamino]benzene, 1,3-bis[isobutyrylamino]-5-pivaloylaminobenzene, 1,3-bis[isobutyrylamino]-5-(2,2-dimethyl-butyryl)aminobenzene, 1,3-bis[isobutyrylamino]-5-(3,3-dimethyl-butyryl)aminobenzene, 1,3-bis[2,2-dimethylbutyrylamino]-5-pivaloylaminobenzene, 1,3-bis[2,2-dimethylbutyrylamino]-5-isobutyrylaminobenzene, 1,3-bis[2,2-dimethylbutyrylamino]-5-(3,3-dimethylbutyryl)-aminobenzene, 1,3-bis[3,3-dimethylbutyrylamino]-5-pivaloylamino-benzene, 1,3-bis[3,3-dimethylbutyrylamino]-5-isobutyryl-aminobenzene, 1,3-bis[3,3-dimethylbutyrylamino]-5-(2,2-dimethyl-butyrylamino)aminobenzene or 1,3,Examples thereof include 5-tris[3-(trimethylsilyl)propionylamino]benzene.,

[0036] Such compounds can be produced, for example, by the production methods described in Published Patent No. 2006-518402.,

[0037] Among these, compounds of formula (1) in which the groups R 1 , R 2 and R 3 are the same group are preferred. Among them, compounds of formula (1) in which R 1 , R 2 and R 3 are represented by a tert-butyl group, that is, 1,3,5-tris[2,2-dimethylpropionylamino]benzene are particularly preferred.,

[0038] The nucleating agent (b) is an organic metal phosphate compound represented by the following general formula (2).

Chemical formula

[0039] Specific examples of the organophosphate metal salt compound represented by the general formula (2) include sodium-2,2'-methylene-bis(4,6-di-t-butylphenyl) phosphate, sodium-2,2'-ethylidene-bis(4,6-di-t-butylphenyl) phosphate, sodium-2,2'-methylene-bis(4-cumyl-6-t-butylphenyl) phosphate, lithium-2,2'-methylene-bis(4,6-di-t-butylphenyl) phosphate, lithium-2,2'-ethylidene-bis(4,6-di-t-butylphenyl) phosphate, lithium-2,2'-methylene-bis(4-cumyl-6-t-butylphenyl) phosphate, sodium-2,2'-ethylidene-bis(4-i-propyl-6-t-butylphenyl) phosphate, lithium-2,2'-methylene-bis(4-methyl-6-t-butylphenyl) phosphate, lithium-2,2'-methylene-bis(4-ethyl-6-t-butylphenyl) phosphate, sodium-2,2'-butylidene-bis(4,6-dimethylphenyl) phosphate, sodium-2,2'-butylidene-bis(4,6-di-t-butylphenyl) phosphate, sodium-2,2'-t-octylmethylene-bis(4,6-dimethylphenyl) phosphate, sodium-2,2'-t-octylmethylene-bis(4,6-di-t-butylphenyl) phosphate, sodium-2,2'-methylene-bis(4-methyl-6-t-butylphenyl) phosphate, sodium-2,2'-methylene-bis(4-ethyl-6-t-butylphenyl) phosphate, sodium(4,4'-dimethyl-6,6'-di-t-butyl-2,2'-biphenyl) phosphate, sodium-2,2'-ethylidene-bis(4-s-butyl-6-t-butylphenyl) phosphate, sodium-2,2'-methylene-bis(4,6-dimethylphenyl) phosphate, sodium-2,2'-methylene-bis(4,6-diethylphenyl) phosphate, potassium-2,2'-ethylidene-bis(4,6-di-t-butylphenyl) phosphate, calcium-bis[2,2'-methylene-bis(4,6-di-t-butylphenyl) phosphate], magnesium-bis[2,2'-methylene-bis(4,6-di-t-butylphenyl) phosphate], zinc-bis[2,2'-methylene-bis(4,6-di-t-butylphenyl) phosphate], aluminum-tris[2,2'-methylene-bis(4,6-di-t-butylphenyl) phosphate], calcium-bis[2,2'-methylene-bis-(4-methyl-6-t-butylphenyl) phosphate], calcium-bis[2,2'-ethylidene-bis(4,6-di-t-butylphenyl) phosphate], calcium-bis[2,2'-thiobis(4-methyl-6-t-butylphenyl) phosphate], calcium-bis[2,2'-thiobis(4-ethyl-6-t-butylphenyl) phosphate], calcium-bis[2,2'-thiobis(4,6-di-t-butylphenyl) phosphate], magnesium-bis[2,2'-thiobis(4,6-di-t-butylphenyl) phosphate], magnesium-bis[2,2'-thiobis(4-t-octylphenyl) phosphate], calcium-bis[(4,4'-dimethyl-6,6'-di-t-butyl-2,2'-biphenyl) phosphate], magnesium-bis[2,2'-ethylidene-bis(4,6-di-t-butylphenyl) phosphate], aluminum-tris[2,2'-ethylidene-bis(4,6-di-t-butylphenyl) phosphate] and mixtures of two or more of these can be exemplified. Among these, sodium-2,2'-methylene-bis(4,6-di-t-butylphenyl) phosphate is particularly preferred. As such a nucleating agent, commercially available ones can be used. Specifically, Adeka Corporation's product, trade name: Adeka Stab NA-11 can be mentioned.,

[0040] The nucleating agent (c) is a nucleating agent represented by the general formula (3). [Chemical formula] [In the formula, M 1 and M 2is either a lithium ion, a sodium ion or a potassium ion, or a single metal cation selected from the group consisting of calcium, magnesium, strontium, zinc and monobasic aluminum, and R 1 、R 2 、R 3 、R 4 、R 5 、R 6 、R 7 、R 8 、R 9 and R 10 are the same or different and are each selected from the group consisting of hydrogen, hydroxy, fluorine, chlorine, bromine, iodine, alkyl having 1 to 9 carbon atoms (wherein any two vicinal (bonded to adjacent carbons) or geminal (bonded to the same carbon) alkyls may together form a hydrocarbon ring having up to 6 carbon atoms), alkoxy having 1 to 9 carbon atoms, alkyleneoxy having 2 to 9 carbon atoms, phenyl, amino and alkylamino having 1 to 9 carbon atoms).]

[0041] Here, the term "monobasic aluminum" is well-known and is intended to include an aluminum hydroxy group as a single cation to which two carbonyloxy groups are bonded. Further, in each of these possible salts, the configuration of the asymmetric carbon atom may be either cis or trans, but cis is preferred.

[0042] The nucleating agent represented by the general formula (3) may be used by mixing with other compounds for the purpose of preventing aggregation and the like.

[0043] As such a nucleating agent, commercially available ones can be used. Specifically, those manufactured by Milliken & Company, trade names: Hyperform HPN68L and Hyperform HPN-20E can be mentioned. The structure of the nucleating agent component of Hyperform HPN68L is shown below. Metal represents sodium.

Chemical formula

[0044] The nucleating agent (d) is an aromatic carboxylic acid metal salt, and as a commercially available product, there can be mentioned Kyodo Yakuhin Co., Ltd.'s product with the following formula, trade name: AL-PTBBA. [Chemical formula]

[0045] The nucleating agent (e) is a nucleating agent represented by formula (4), and as a commercially available product, there can be mentioned Shin Nippon Rika Co., Ltd.'s product, trade name: Rika Clear PC-1. [Chemical formula] [In the formula, R 1 represents a propane-1,2,3-triyl group or a butane-1,2,3,4-tetrayl group. Three or four R 2 are the same as or different from each other and each represents a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms. a represents an integer of 3 or 4.]

[0046] (5) Pigment The polypropylene-based resin composition of the present invention may contain a pigment as long as the effects of the present invention are not inhibited. Examples of pigments that can be used in the polypropylene resin composition of the present invention include black carbon black, iron black; white titanium oxide, zinc white, lithopone, lead white; blue ultramarine, ultramarine blue, cobalt blue, phthalocyanine blue, indanthrene blue RS, fast sky blue lake, alkali blue lake, victoria blue lake; red carmine, lead charcoal, molybdenum red, cadmium red, lake red C, lake red D, brilliant carmine 6B, resorcin red, permanent red 4R, watching red, thioindigo red, alizarin red, quinacridone red, rhodamine lake, orange lake, benzimidazolone red, pyrazolone red, condensed azo red, perylene red, permanent carmine FB, quinacridone magenta; yellow lead yellow, cadmium yellow, titanium yellow, iron yellow, isoindolinone yellow, benzidine yellow, fast yellow, flavanthrone yellow, naphthol yellow, quinoline yellow, benzimidazolone yellow, HR yellow, condensed azo yellow; green chrome green, chromium oxide, guinea green, spinel green, phthalocyanine green, pigment green B, naphthol green, acid green lake, malachite green lake; orange chrome orange, cadmium orange, benzimidazolone orange, perinone orange; brown zinc ferrite; purple manganese purple, cobalt purple, purple carmine, fast violet B, methyl violet lake, dioxazine violet, etc. Pigments that can be used within a range that does not inhibit the effects of the present invention are preferably those with a small particle size. If the particle size of the pigment is too large, poor dispersion may occur on the surface of the molded article.

[0047] In the present invention, the compounding amount of the pigment is usually 0.01 to 20 parts by weight, preferably 0.025 to 15 parts by weight, more preferably 0.05 to 10 parts by weight, still more preferably 0.075 to 5 parts by weight, and particularly preferably 0.1 to 2 parts by weight per 100 parts by weight of the polypropylene-based resin composition. By setting the compounding amount within the above range, it becomes possible to easily adjust the color and obtain good color development properties. That is, when the compounding amount of the pigment is less than 0.01 part by weight, the uniformity of coloring may deteriorate and color unevenness may occur. On the other hand, when the compounding amount exceeds 20 parts by weight, adverse effects on physical properties such as a decrease in rigidity may be considered.

[0048] The pigment can be directly compounded into the polypropylene-based resin composition, but it is preferably used in the form of a masterbatch from the viewpoints of handling and compounding operability of the pigment. For example, in addition to the components (A) and (B) used in the polypropylene-based resin composition, a masterbatch having a pigment content of 20 to 80% by weight with polyethylene wax, polyethylene, etc. as matrix components can be used.

[0049] (6) Optional additive components In the polypropylene-based resin composition of the present invention, in addition to the above components (A), (B), (C), and the pigment, optional additive components can be further compounded as needed within a range that does not significantly impair the effects of the present invention, for example, to further improve the desired effects or impart other performance / effects. The addition amount of the optional additive components is usually 0.2 to 2.0% by weight based on the entire polypropylene-based resin composition. Specific examples of optional additives include antistatic agents such as nonionic types, light stabilizers such as hindered amine types, ultraviolet absorbers such as benzotriazole types, foaming agents such as physical foaming agents, dispersants such as organic metal salt types, antioxidants such as phenol types, neutralizing agents such as inorganic compounds, lubricants such as fatty acid amide types, metal deactivators such as nitrogen compounds, surfactants such as nonionic types, antibacterial and antifungal agents such as thiazole types, flame retardants such as halogen compounds, fluorescent brighteners, anti-foaming agents, crosslinking agents, peroxides, process oils (compounding oils), antiblocking agents, plasticizers, polyolefins such as polypropylene other than the above component (A), thermoplastic resins such as polyamides and polyesters, fillers such as talc with a small particle size, elastomers (rubber-like polymers), and other additives. These components may be used in combination of two or more, may be added later to the polypropylene-based resin composition of the present invention, may be added to each component, and two or more may be used in combination in each component.

[0050] [II] Production of Polypropylene-Based Resin Composition The polypropylene-based resin composition of the present invention is prepared by blending the above component (A), component (B), and, if necessary, component (C) and optional additives such as pigments in the above blending ratios, and mixing them by a known method such as a tumbler mixer, super mixer, Henschel mixer, screw blender, ribbon blender, or kneading and pelletizing them using a usual kneader such as a single-screw extruder, twin-screw extruder, Banbury mixer, roll mixer, Brabender plastograph, kneader, etc.

[0051] In this case, it is desirable to select a kneading and pelletizing method that can achieve good dispersion of each component, and usually a twin-screw extruder is used. During this kneading and pelletizing, the blends of the above components may be kneaded simultaneously, or, in order to improve performance, each component may be divided, for example, first kneading component (A) and part or all of component (B), and then kneading and pelletizing the remaining components.

[0052] [III] Molding and Applications of Polypropylene-Based Resin Composition (1) Molding The molding of the polypropylene resin composition of the present invention can be carried out by injection molding (including gas injection molding) or injection compression molding (including press injection, hot flow stamping molding, gas injection compression molding). Among them, injection molding other than gas injection molding and injection compression molding (press injection) can more effectively obtain the effects of the present invention, and it is preferable to obtain a molded body by such a molding method. For the molding of the polypropylene resin composition of the present invention, various molding methods such as blow molding, extrusion molding, compression (press) molding, foaming (expansion) molding, sheet molding, thermoforming, stamping molding, powder molding, etc. can also be applied as necessary, and thereby a desired molded body (for example, an extruded body) can also be obtained. Among them, molding methods other than foaming (expansion) molding are preferable.

[0053] (2) Applications The molded body obtained from the polypropylene resin composition of the present invention is excellent in mechanical properties such as density, heat distortion temperature, and impact strength, and in shrinkage anisotropy. The molded body obtained from the polypropylene resin composition of the present invention can be suitably used in applications such as automotive parts and household electrical appliances and lighting fixtures.

Examples

[0054] The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In addition, the materials, granulation methods, and evaluation methods used in the examples are as follows.

[0055] 1. Materials (1) Component (A) Novatec PP MA04C (manufactured by Nippon Polypro Co., Ltd.) A propylene homopolymer produced using a Ziegler catalyst, melt flow rate (MFR, 230 ° C, 2.16 Kg load) 40 g / 10 min, melting peak temperature (Tm) = 166 ° C, density: 0.90 g / cm 3 (2) Component (B) Wintec PP WMH02 (manufactured by Nippon Polypro Co., Ltd.) Propylene-ethylene random copolymer (ethylene concentration: 0.35% by weight) produced using a metallocene catalyst, melt flow rate (MFR, 230 °C, 2.16 Kg load) 20 g / 10 min, density: 0.90 g / cm 3 , melting peak temperature (Tm) = 152 °C (3) Nucleating agent (C) (C-1) Adeka Stab NA-11 (manufactured by ADEKA CORPORATION) 2,2'-Methylenebis(4,6-di-t-butylphenyl) sodium phosphate (C-2) AL-PTBBA (manufactured by Kyodo Yakuhin Co., Ltd.) Aluminum hydroxy-di(p-tert-butylbenzoate)

[0056] 2. (Examples 1 to 5 and Comparative Examples 1 to 2) Each component was mixed at the ratios shown in Table 1 and kneaded and granulated under the following conditions. The ratio of the nucleating agent in the table is the value shown in parts by weight based on 100 parts by weight of the polyolefin resin. At this time, 0.1 part by weight of Adeka Stab AO20 manufactured by ADEKA CORPORATION and 0.1 part by weight of Irgafos 168 manufactured by BASF were blended as heat stabilizers, and 0.05 part by weight of calcium stearate G) manufactured by NOF CORPORATION was blended as a neutralizing agent per 100 parts by weight of the polyolefin resin. After blending for 3 minutes with a Super Floater SFC-50 manufactured by Kawata Co., Ltd., the kneaded strands were kneaded under the following kneading conditions and extruded, and then cut to granulate pellets. The test pieces obtained by injection molding the obtained pellets for mechanical properties and shrinkage properties were evaluated under the following conditions. The evaluation results are shown in Table 1. Kneading apparatus: KCM50 type twin-screw extruder manufactured by Kobe Steel, Ltd. Kneading conditions: temperature = 200 °C, screw rotation speed = 800 rpm (Test piece for mechanical properties) Injection molding apparatus: Toshiba injection molding machine EC100 and ISO mold type A Injection molding conditions: injection primary pressure 50 MPa, molding temperature 200 °C, mold cooling water temperature 40 °C, molding cycle 15 seconds (Test piece for shrinkage properties) Injection molding machine: Toshiba IS100GN and mold of 100 mm × 100 mm × 2 mm (T) Injection molding conditions: Injection primary pressure 70 MPa, molding temperature 240 °C, mold cooling water temperature 60 °C, molding cycle 50 seconds

[0057] 3. Evaluation method (1) Density The density was measured by the water substitution method in accordance with JIS-K7112. The unit is g / cm 3 . (2) Heat distortion temperature (HDT) It was measured in accordance with JIS-K7191-1 at a flexural stress of 0.45 MPa. (3) Impact strength (Charpy impact strength (notched)): It was measured in accordance with JIS K7111 (notched) at a test temperature of 23 °C (the unit is kJ / m 2 ). (4) Shrinkage anisotropy The obtained test pieces were held in a constant temperature chamber at 23 °C and a relative humidity (RH) of 50% for 48 hours (conditioning), and then the shrinkage rates in the MD direction and TD direction were measured using a projector (manufactured by NIKON, model number PROFILE PROJECTOR V-16E). The shrinkage rates shown in Table 1 are the values obtained by multiplying the measured values by 10 3 . Shrinkage anisotropy was evaluated based on these shrinkage rates as "shrinkage rate TD - shrinkage rate MD".

[0058]

Table 1

[0059] 4. Evaluation From the results shown in Table 1, it can be understood that Examples 1 to 5 of the polypropylene-based resin composition of the present invention that satisfy the invention requirements are excellent in density, heat distortion temperature, and shrinkage anisotropy. Thus, since Examples 1 to 5 are all determined to have achieved good or practical levels in all evaluations, it has become clear that the polypropylene-based resin composition of the present invention can be suitably used in applications such as automotive parts and household electrical appliance lighting fixtures. On the other hand, Comparative Examples 1 and 2 that do not meet the invention requirements of the polypropylene resin composition of the present invention have a large anisotropy in shrinkage rate and are inferior to Examples 1 to 5.

Industrial Applicability

[0060] The polypropylene resin composition of the present invention and the molded article obtained therefrom have suppressed density, heat distortion temperature, and shrinkage anisotropy. Therefore, they can be suitably used in applications such as automotive parts and household electrical appliance lighting fixtures. It can be done.

Claims

1. A polypropylene resin composition comprising 85 to 99.5% by weight of a component (A) satisfying the following conditions (A-1) and (A-2), and 0.5 to 15% by weight of a component (B) satisfying the following conditions (B-1) to (B-3): (the total of components (A) and (B) is 100% by weight), and 0.01 to 0.25 parts by weight of a nucleating agent (C) per 100 parts by weight of the polypropylene resin composition. Condition (A-1): Component (A) is a propylene homopolymer having a melt flow rate (MFR, 230°C, 2.16 kg load) in the range of 0.5 to 100 g / 10 min. Condition (A-2): Component (A) exhibits a peak melting temperature (Tm) in the range of 160 to 175°C when measured by the DSC method. Condition (B-1): Component (B) is a propylene-α-olefin random copolymer (wherein the α-olefin is an α-olefin having 2 to 8 carbon atoms (excluding 3 carbon atoms)), and the content of the α-olefin is 0.1 to 5% by weight (wherein the total of the propylene and α-olefin in component (B) is 100% by weight). Condition (B-2): The melt flow rate (MFR, 230°C, 2.16 kg load) of component (B) is in the range of 0.5 to 100 g / 10 min. Condition (B-3): Component (B) exhibits a peak melting temperature (Tm) in the range of 110°C or higher and lower than 160°C when measured by a DSC method.

2. A molded article obtained from the polypropylene resin composition according to claim 1.

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