JP2010144133A - Straight chain polypropylene-based resin composition, injection foam molded product and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a straight chain polypropylene-based resin composition excellent in surface appearance, injection foam moldability and physical properties such as rigidity, enabling large weight reduction, and excellent in recyclability, foam molded products and a method for producing the same. <P>SOLUTION: The straight chain polypropylene-based resin composition or the like comprises a polypropylene-based resin (A) comprising a straight chain propylene-ethylene block copolymer (A-1) having characteristics (i)-(vi) and a propylene-based polymer (A-2), and a foaming agent (B). The characteristics (i): the MFR of a straight chain propylene polymer section is ≥130 g/10 minutes, (ii) the ratio of the straight chain random copolymer section to the component A is 2-50 wt.%, (iii): the MFR is over 45 g/10 minutes, (iv) the die swell ratio is 1.2-2.5, (v): strain-hardening properties are expressed in measuring elongation viscosity at 180°C and (vi) the ratio (N1/SS) of the first normal stress difference (N1) to the shear strength (SS) in melt viscoelasticity measurement is ≥1.01. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a linear polypropylene-based resin composition, an injection foam molded article, and a method for producing the same, and more specifically, a linear form that has excellent surface appearance, good injection foam moldability, and can be significantly reduced in weight. The present invention relates to a polypropylene resin composition, an injection foamed molded article, and a method for producing the same.

Conventionally, polypropylene-based resins have good physical properties and moldability, and their use range is rapidly expanding as environmentally friendly materials. In particular, automobile parts and the like are provided with polypropylene-based resin products that are lightweight and excellent in rigidity, and one such product is an injection-foamed molded product of polypropylene-based resin.
In the injection molding of the polypropylene-based resin, so-called injection foam molding for foaming has been conventionally performed for the purpose of weight reduction, cost reduction, and prevention of warping and sink marks of the molded body (for example, see Patent Document 1). Further, in recent years, in the automobile field, further weight reduction has been achieved in order to improve fuel efficiency (reduction of CO ₂ emissions), and it has been necessary to significantly reduce the thickness, for example, to form products having a thin portion of about 1 to 2 mm. It is.
However, polypropylene resin has a low melt tension (melting tension), and bubbles are easily destroyed. As a result, voids were easily generated inside, and it was difficult to increase the expansion ratio. Moreover, since the bubbles were non-uniform and large, the resulting molded article was not sufficiently rigid. The term “void” as used herein refers to a coarse bubble that is generated when internal bubbles communicate with each other and substantially has a diameter exceeding 1.0 mm.

  As a method for improving the foamability of polypropylene, for example, a method of adding a foaming agent and a crosslinking aid to polypropylene and producing a foam while cross-linking the molecules has been proposed (see, for example, Patent Document 2). .) However, even with this method, the melt tension of the polypropylene is insufficiently improved, and the odor is a problem as a result of the remaining crosslinking aid remaining in such polypropylene.

By introducing long-chain branching by irradiation, the polypropylene has a higher melt tension than ordinary linear polypropylene resins, and the viscosity increases as the stretch distortion of the melt increases. The resin is commercially available from Sun Allomer as HMS-PP (High Melt Strength Polypropylene) (see Patent Document 3).
It is also known that a foam molded body can be obtained by using such HMS-PP as a base resin for injection foam molding (see Patent Document 4).
Normally, in order to achieve significant weight reduction while maintaining rigidity, the mold cavity clearance thickness (thickness before foaming) at the time of injection filling is significantly thinner than the non-foamed injection molded body before weight reduction. However, it is necessary to make it highly foamed. However, the HMS-PP used here has a melt flow rate of only about 4 g / 10 min and low fluidity at the time of melting, so it has a significant thickness reduction, for example, a thickness of about 1 to 2 mm. In molding, there is a problem that a short shot tends to occur. In addition, thermoplastic resins having a crosslinked structure tend to be difficult to be melt-processed again, and there are problems in terms of the cost of the foam, the amount of waste, and the recycling of resources.

  Further, by using a thermoplastic resin that does not have a cross-linked structure that defines the melt index (MI) and the capillary swell ratio, good foam cell control and a foamed article with high appearance have been achieved (for example, Patent Document 5). 6)), however, as the molded body becomes larger, complicated, and thinner, an injection foam molded body that maintains a good cell shape when foamed with a high magnification and reduced thickness before foaming is obtained. It was difficult.

  In addition, by using a propylene-based multistage polymer or a polypropylene resin composition that defines the intrinsic viscosity of a propylene homopolymer component or a copolymer component, and further defines a melt index (MI) and a melt flow index (MFR), An injection-foamed molded article with excellent moldability and appearance has been obtained, but as the molded article becomes larger, more complicated, and thinner, it tends to become a short shot and the appearance is often insufficient. (For example, refer to Patent Documents 7 and 8.)

On the other hand, as a manufacturing method for obtaining a foamed molded article having a good surface appearance, various methods have been conventionally proposed. For example, after forming a skin layer by injecting and filling a polypropylene resin into a narrow mold cavity while reversing the movable mold at a pressure equal to or higher than the foaming pressure, the movable mold is further retracted after the filling is completed. With the manufacturing method for foaming, a foamed molded article having a good surface appearance can be obtained without a special device (see, for example, Patent Document 9).
However, all of the foamed molded products obtained by these methods have a low expansion ratio of less than 2 times, and a high expansion ratio is not obtained.

In addition, using a material comprising a linear polypropylene resin, a modified polypropylene resin exhibiting strain hardening obtained by melt-kneading a radical polymerization initiator and a conjugated diene compound, and a foaming agent, the mold is a fixed mold. And a step of injecting and filling the molten mixture into a cavity having a clearance (t ₀ ) smaller than the thickness (t ₁ ) of the molded body before foaming, which is composed of a movable mold capable of moving forward and backward, and then retracting the movable mold step complete injection filling up the clearance corresponding to the allowed foamed previous moldings thickness (t _1), the manufacturing method of the injection foam molded article comprising a step of further foaming the polypropylene-based resin by retracting the movable mold Proposed injection foam moldability and surface appearance are excellent, and an injection foam molded article having a high expansion ratio is obtained (for example, see Patent Document 10).
However, as the molded body becomes larger, more complicated, and thinner, it tends to become a short shot, and the appearance, expansion ratio, and recyclability are often insufficient.

Under these circumstances, the problems of conventional polypropylene resin compositions have been solved, and injection foam molded products that are relatively large, complicated in design, and thinned, especially injection foam molded products for automobile parts, especially trim. It is the performance necessary for obtaining injection foam moldings for automobile interior parts such as ceilings, trunks, etc., excellent surface appearance, good injection foam molding properties, can be significantly reduced in weight, and recycled Research and development are required for polypropylene resin compositions, injection-foamed molded articles, and methods for producing the same, which have excellent properties and improved physical properties such as rigidity.
JP-A-6-198668 Japanese Examined Patent Publication No. 45-40420 Japanese Patent Laid-Open No. 62-121704 (Japanese Patent Publication No. 7-45551) JP 2001-26032 A JP-A-8-231816 JP 2004-307665 A International Publication No. WO2005 / 097842 JP 2006-152271 A JP 2003-11190 A JP 2005-224963 A

In view of the above-mentioned problems of the prior art, the object of the present invention is that when used in an injection foam molded article, the surface appearance is excellent, the injection foam moldability is good, the weight can be significantly reduced, and the recyclability is also good. An object of the present invention is to provide a linear polypropylene resin composition excellent in physical properties such as rigidity, an injection foam molded article, and a method for producing the same.
Incidentally, in this specification, excellent surface appearance means that it has a good appearance while suppressing the occurrence of silver streak, and good injection foam moldability means that the surface tension is good and the set foaming ratio. It means that the cell diameter is uniform and the cell diameter is uniform. The surface tension represents the uniformity of the surface on the surface of the molded body, and that the surface tension is good means that the entire surface of the molded body has no irregularities, and there are partial dents and bulges. It is to indicate that there is no state.

  As a result of intensive studies to solve the above problems, the present inventors have found that a linear chain having a specific property / performance comprising a linear propylene polymer portion and a linear ethylene / propylene random copolymer portion. Polypropylene resin (component A) composed of 30 to 100% by weight of propylene / ethylene block copolymer (component A-1) and 0 to 70% by weight of other propylene polymer (component A-2), and foaming agent (Component B) If necessary, a filler (Component C) and an elastomer (Component D) were blended, and the content ratio of each component was optimized. 30 to 100% by weight of a linear propylene / ethylene block copolymer (component A-1) having specific properties and performance such as showing curability and other propylene polymers (component A-2) 0 to 70 weight When a foaming agent (component B) is blended with a polypropylene resin (component A) consisting of a resin composition for injection foam molding, the surface appearance is excellent, injection foam moldability is good, and significant weight reduction is possible. It was found that a linear polypropylene resin composition having excellent recyclability and improved physical properties such as rigidity and an injection-foamed molded article thereof were obtained, and based on these findings, the present invention was completed. It was.

That is, according to the first aspect of the present invention, the linear propylene polymer portion and the linear ethylene / propylene random copolymer portion have the following characteristics (i) to (vi). Propylene / ethylene block copolymer (component A-1) 30 to 100% by weight, other propylene polymer (component A-2) 0 to 70% by weight polypropylene resin (component A), and foaming agent A linear polypropylene resin composition comprising (Component B) is provided.
Characteristic (i): The melt flow rate (230 ° C., 2.16 kg load) of the linear propylene polymer portion is 130 g / 10 min or more.
Characteristic (ii): The ratio of the linear ethylene / propylene random copolymer portion to the entire linear propylene / ethylene block copolymer (component A) is 2 to 50% by weight.
Characteristic (iii): Melt flow rate (230 ° C., 2.16 kg load) exceeds 60 g / 10 min.
Characteristic (iv): Die swell ratio is 1.2 to 2.5.
Characteristic (v): Shows strain hardening in 180 ° C. extensional viscosity measurement.
Characteristic (vi): The ratio (N1 / SS) between the first normal stress difference (N1) and the shear stress (SS) in the melt viscoelasticity measurement is 1.01 or more.

According to the second invention of the present invention, in the first invention, the linear propylene / ethylene block copolymer (component A-1) has an intrinsic viscosity of the linear ethylene / propylene random copolymer portion [ _{eta] copoly} linear polypropylene-based resin composition is provided which is a 5.3~15.0dl / g.
According to the third invention of the present invention, in the first or second invention, the weight average molecular weight (Mw) and the number average molecular weight of the whole linear propylene / ethylene block copolymer (component A-1) ( A linear polypropylene-based resin composition having a ratio (Q value: Mw / Mn) to Mn) of 7 to 13 is provided.
Furthermore, according to the fourth aspect of the present invention, in any one of the first to third aspects, the linear ethylene / propylene random copolymer in the linear propylene / ethylene block copolymer (component A-1) is used. An ethylene content of the polymer portion is 15 to 80% by weight based on the total amount of the linear ethylene / propylene random copolymer, and a linear polypropylene resin composition is provided.

According to the fifth aspect of the present invention, in any one of the first to fourth aspects, the filler (component C) is contained in an amount of 1 to 70 parts by weight with respect to 100 parts by weight of the polypropylene resin (component A). A linear polypropylene-based resin composition is provided.
Furthermore, according to a sixth invention of the present invention, in the fifth invention, the filler (component C) is at least one selected from talc, polyester fiber, whisker, glass fiber or carbon fiber. A linear polypropylene resin composition is provided.

  According to the seventh invention of the present invention, in any one of the first to sixth inventions, the elastomer (component D) is contained in an amount of 1 to 50 parts by weight with respect to 100 parts by weight of the polypropylene resin (component A). A linear polypropylene-based resin composition is provided.

According to an eighth aspect of the present invention, there is provided an injection foam molded article comprising the linear polypropylene resin composition according to any one of the first to seventh aspects.
Furthermore, according to the ninth aspect of the present invention, the mold is composed of a fixed mold and a movable mold capable of moving forward and backward, and from the mold cavity clearance (T ₁ ) corresponding to the shape position of the final product. An injection process of injecting and filling a molten or semi-molten linear polypropylene resin composition into a mold cavity having a smaller mold cavity clearance (T ₀ ), and mold cavity clearance (T ₁ ) An injection foam molded article made of a linear polypropylene resin composition is produced by a mold opening injection molding method comprising a foaming step in which the movable mold is retracted to fill the void of the mold cavity with an expansion pressure by a foaming agent. In the injection process in which a linear polypropylene resin composition is injection-filled, the injection rate for a pre-foamed molded body filling volume of 100% is 20 / Eighth production method of injection foam molded body according to the invention, characterized by molding in seconds or more conditions are provided.

As described above, the present invention relates to a linear polypropylene resin composition and the like, and preferred embodiments include the following.
(1) In the first invention, the foaming agent (component B) comprises (i) sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, ammonium nitrite, azodicarbonamide (ADCA), N, N′-di A chemical blowing agent selected from nitrosopentamethylenetetramine, benzenesulfonylhydrazide or 4,4′-diphenyldisulfonyl azide, (ii) a physical blowing agent selected from carbon dioxide, nitrogen, argon or helium, or (iii) a blowing agent (expansion) A linear polypropylene-based resin composition, which is a microcapsule encapsulating an agent.
(2) In the invention of (1), the blending amount of the foaming agent (component B) is 0.001 to 10 parts by weight with respect to 100 parts by weight of the polypropylene resin (component A) in the case of a chemical foaming agent. In the case of a physical foaming agent, a linear polypropylene resin composition characterized in that the amount is a supercritical state.
(3) In the first invention, the linear propylene polymer portion of the linear propylene / ethylene block copolymer (component A-1) is polymerized by a multistage polymerization method, preferably a two-stage polymerization method. A linear polypropylene-based resin composition characterized by being:
(4) In the first invention, the linear propylene / ethylene block copolymer (component A-1) has strain hardening in 180 ° C. extensional viscosity measurement, and in 180 ° C extensional viscosity measurement, the strain rate is A linear polypropylene-based resin composition having a strain hardening degree (λmax) value of 2.0 or more at 1.0 / sec.
(5) In the eighth invention, an injection foam molded article having a foamed layer having an average cell diameter of 500 μm or less and a non-foamed layer having a thickness of 10 to 1000 μm.
(6) In the eighth aspect of the invention, an injection foam molded article having an expansion ratio of 2.0 to 10 times.

  The linear polypropylene resin composition and injection-foamed molded article of the present invention have excellent surface appearance, good injection-foaming moldability, and can be significantly reduced in weight, despite no cross-linking modification. In addition, it has excellent recyclability and exhibits remarkable effects of improving physical properties such as rigidity. In particular, molding is possible in the region where the absolute molding wall thickness before foaming is less than 2 mm, especially 1.5 mm or less, which has been difficult in the past, and it is possible to significantly reduce the weight by expressing a uniform high foaming ratio. Become. In addition, since cross-linking modification is not performed, recyclability is excellent and environmental adaptability is also good. Therefore, it can be suitably used for injection molded parts including automobile interior parts such as trims, ceiling materials, and trunks.

The present invention includes 30 to 100% by weight of a linear propylene / ethylene block copolymer (component A-1, hereinafter simply referred to as component A-1) and other propylene-based polymers (component A-2, hereinafter simply referred to as component A-1). Polypropylene resin (component A, hereinafter also simply referred to as component A) composed of 0 to 70% by weight (also referred to as component A-2), foaming agent (component B, hereinafter also referred to simply as component B), and as necessary. A linear polypropylene resin characterized by containing each component of filler (component C, hereinafter also simply referred to as component C) and elastomer (component D, hereinafter also simply referred to as component D) to be blended. It is a composition and an injection foaming molding.
Hereinafter, each component of the linear polypropylene resin composition, the production of the linear polypropylene resin composition, the production of the injection-foamed molded article, and the like will be described in detail.

[I] Constituent Components of Linear Polypropylene Resin Composition Polypropylene resin (component A)
The polypropylene resin (component A) used in the linear polypropylene resin composition of the present invention is 30 to 100% by weight, preferably a linear propylene / ethylene block copolymer (component A-1) described below. 40 to 100% by weight, particularly preferably 50 to 100% by weight, and other propylene polymer (component A-2) 0 to 70% by weight, preferably 0 to 60% by weight, particularly preferably 0 to 50% by weight. %.
Here, when the component A-1 is less than 30% by weight, the surface appearance and the injection foam moldability of the linear polypropylene resin composition of the present invention and the injection foam molded article thereof are deteriorated.
In addition, the compounding ratio of each component in the linear polypropylene resin composition of the present invention is based on 100 parts by weight of component A.

1-1. Linear propylene / ethylene block copolymer (component A-1)
The linear propylene / ethylene block copolymer (component A-1) used in the linear polypropylene resin composition of the present invention is composed of a linear propylene polymer portion and a linear ethylene / propylene random copolymer. It is a linear propylene / ethylene block copolymer composed of a combined portion.
Component A-1 has the following characteristics (i) to (vi), and in a linear polypropylene resin composition, has excellent surface appearance and high injection foam moldability (surface tension, expansion ratio, cell form) ).
Characteristic (i): Melt flow rate (hereinafter referred to as MFR) (230 ° C., 2.16 kg load) of the linear propylene polymer portion is 130 g / 10 min or more.
Characteristic (ii): The ratio of the linear ethylene / propylene random copolymer portion to the whole component A-1 is 2 to 50% by weight.
Characteristic (iii): MFR (230 ° C., 2.16 kg load) exceeds 60 g / 10 min.
Characteristic (iv): Die swell ratio is 1.2 to 2.5.
Characteristic (v): Shows strain hardening in 180 ° C. extensional viscosity measurement.
It is.
Characteristic (vi): The ratio (N1 / SS) between the first normal stress difference (N1) and the shear stress (SS) in the melt viscoelasticity measurement is 1.01 or more.

Here, the “linear” in the linear propylene polymer portion, the linear ethylene / propylene random copolymer portion or the linear propylene / ethylene block copolymer (component A-1) is a methyl branch. This means that there are very few branched structures other than the structure, and this is a structure often found in ordinary polypropylene resins.
For example, it can be confirmed by ¹³ C-NMR analysis that no peak is observed at 31.5 to 31.7 ppm based on branched carbon (see Macromol. Chem. Phys. 2003, Vol. 204, page 1738).

  As described above, component A-1 exhibits strain-hardening properties even though it has a linear structure. This strain hardening property is usually said to be caused by molecular entanglement. In order to develop the strain hardening property, for example, the molecular weight of the linear propylene polymer portion and the linear propylene / ethylene random copolymer weight are used. Examples of the method include increasing the difference in molecular weight of the combined portion, and increasing the compatibility between the linear propylene polymer portion and the linear propylene / ethylene random copolymer portion.

Component A-1 not only satisfies these requirements, but also has a unique dispersion structure of the linear ethylene / propylene random copolymer portion in the linear propylene polymer portion, that is, general propylene / ethylene. Unlike the case of a block copolymer (in this case, when subjected to shearing, the ethylene / propylene random copolymer portion is rejected and aggregated at the interface of the propylene polymer portion and dispersed individually), It exhibits a kind of network-like state (that is, the linear ethylene / propylene random copolymer portion soaks into the linear propylene polymer portion in a network shape), so that it has strain hardening properties. It is considered to show.
In addition, by exhibiting a state that approximates a kind of network, the compatibility between the linear propylene polymer portion and the linear ethylene / propylene random copolymer portion is further enhanced, Has been considered.

  The effect of exhibiting the strain hardening property is attributed to foam breakage at the molten resin flow front end (flow front) at the time of injection foam molding in the linear polypropylene resin composition and injection foam molded article of the present invention. Silver streak is unlikely to occur, the surface appearance is likely to be beautiful, and an injection foam molded article having uniform fine bubbles at a high magnification is likely to be obtained.

(1) Production The linear propylene / ethylene block copolymer (component A-1) used in the present invention can be produced by a semi-batch method using a single reactor.
Hereinafter, a polymerization solvent, a polymerization catalyst, and hydrogen are charged into a single reactor, and propylene and hydrogen are continuously supplied to produce a linear propylene polymer. The reactor gas is purged once, and then propylene, ethylene The semi-batch process for producing and taking out a linear ethylene / propylene random copolymer will be described.

(I) Polymerization reactor The polymerization reactor is not particularly limited in shape and structure, but is generally used in a tank with a stirrer generally used in slurry polymerization and bulk polymerization, a tube reactor, and gas phase polymerization. Examples thereof include a fluidized bed reactor and a horizontal reactor having a stirring blade. In the polymerization method using a single reactor, polymerization is performed using one reactor selected from these throughout the polymerization process.

(Ii) Polymerization catalyst The total amount of the polymerization catalyst is preferably present at the start of the polymerization, and is preferably involved in the polymerization from the beginning of the polymerization, and it is preferable not to add a new catalyst after the start of the polymerization. If a new catalyst is not added after the start of polymerization, a powder with a high ratio of the ethylene / propylene random copolymer to the crystalline propylene polymer produced by the added catalyst will cause deterioration of the powder properties and gel generation. Can be suppressed.

  The kind of the polymerization catalyst is not particularly limited, and a known catalyst can be used. For example, a so-called Ziegler-Natta catalyst or a metallocene catalyst (for example, disclosed in JP-A-5-295022) in which a titanium compound and organoaluminum are combined can be used. Since the intrinsic viscosity of the rubber component is preferably relatively high, a Ziegler-Natta catalyst with less chain transfer during polymerization is more preferable. A Ziegler-Natta catalyst is a titanium trichloride or titanium trichloride composition obtained by reduction with organoaluminum or the like as a titanium compound and treated with an electron donating compound (for example, JP-A-47-34478). And disclosed in JP-A-58-23806 and JP-A-63-146906), and by supporting titanium tetrachloride on a carrier such as magnesium chloride. 58-157808, JP-A-58-83006, JP-A-58-5310, and JP-A-61-2218606). As these catalysts, known catalysts can be used without particular limitation.

  Moreover, an organoaluminum compound is used as a promoter. For example, trialkylaluminum such as trimethylaluminum, triethylaluminum and triisobutylaluminum, alkylaluminum halide such as diethylaluminum chloride and diisobutylaluminum chloride, alkylaluminum hydride such as diethylaluminum hydride, alkylaluminum alkoxide such as diethylaluminum ethoxide, methyl Examples include alumoxanes such as alumoxane and tetrabutylalumoxane, and complex organoaluminum compounds such as dibutyl methylboronate and lithium aluminum tetraethyl. It is also possible to use a mixture of two or more of these.

  In addition, various polymerization additives for the purpose of improving stereoregularity, controlling particle properties, controlling soluble components, controlling molecular weight distribution, and the like can be used for the above-described catalyst. For example, organic silicon compounds such as diphenyldimethoxysilane and tert-butylmethyldimethoxysilane, esters such as ethyl acetate, butyl benzoate, methyl p-toluate and dibutyl phthalate, ketones such as acetone and methyl isobutyl ketone, diethyl ether And electron donating compounds such as ethers such as benzoic acid and propionic acid, and alcohols such as ethanol and butanol.

(Iii) Polymerization format and polymerization solvent As the polymerization format, slurry polymerization using an inert hydrocarbon such as hexane, heptane, octane, benzene or toluene as a polymerization solvent, bulk polymerization using propylene itself as a polymerization solvent, Gas phase polymerization in which propylene is polymerized in a gas phase state is possible. Moreover, it is also possible to carry out by combining these polymerization formats.
For example, linear propylene polymer polymerization is performed by bulk polymerization, linear ethylene / propylene random copolymer polymerization is performed by gas phase polymerization, and linear propylene polymer polymerization is followed by bulk polymerization. Examples of the method include vapor phase polymerization, and polymerization of the linear ethylene / propylene random copolymer by vapor phase polymerization.

(Iv) Polymerization additive Although the polymerization additive depends on the combination with the catalyst, the case where an aromatic ester such as butyl benzoate is added to the titanium trichloride catalyst consumes more hydrogen. preferable.

(V) Polymerization pressure In the semi-batch polymerization, it is possible to carry out the polymerization pressure at a constant value or to change it as needed during the production of the linear propylene polymer. When the polymerization pressure is set high, there is an advantage that the catalytic activity can be increased, but there is a disadvantage that the amount of unreacted propylene to be recovered increases. Therefore, the polymerization pressure is 0.2 to 5 MPa, preferably about 0.3 to 2 MPa. Is preferred.
Further, it is possible to carry out the polymerization pressure at a constant value or to change the polymerization pressure at any time during the production of the linear ethylene / propylene random copolymer, but it is preferable to carry out at about 0.1 to 0.2 MPa. .

(Vi) Polymerization temperature Although it does not specifically limit regarding polymerization temperature in this invention, Usually, 20-100 degreeC, Preferably it selects from the range of 40-80 degreeC. This polymerization temperature may be the same or different at the start of polymerization and at the end of polymerization.

(Vii) Polymerization time In this invention, although superposition | polymerization time is also not specifically limited, Usually, it implements in 30 minutes-10 hours. In general, the production of linear propylene polymer is typically 2 to 5 hours for gas phase polymerization, 30 minutes to 2 hours for bulk polymerization, and 4 to 8 hours for slurry polymerization. The standard of the polymer is 1 to 3 hours for gas phase polymerization, 20 minutes to 1 hour for bulk polymerization, and 1 to 3 hours for slurry polymerization.

(Viii) Production of linear propylene polymer portion In the successive multi-stage polymerization step of at least two stages, hydrogen is supplied as propylene and a chain transfer agent in the previous polymerization step, and propylene is present in the presence of the catalyst. Homopolymerization is performed to produce a linear propylene polymer portion.
At this time, the MFR of the linear propylene polymer portion in the linear propylene / ethylene block copolymer (component A-1) is not only to be 130 g / 10 min or more, but also to the first normal stress. In order to make the ratio to the shear stress 1.01 or more, hydrogen and propylene are supplied into the reactor in the previous polymerization step, and the hydrogen concentration relative to propylene is decreased with time in the presence of the catalyst. When propylene is polymerized while a linear propylene polymer is obtained, the gas concentration ratio (H ₂ / C ₃ ) between hydrogen and propylene in the unreacted gas should be kept below 0.1 molar ratio. Is preferred.

Examples of the method for controlling the gas concentration ratio (H ₂ / C ₃ ) of hydrogen and propylene in the unreacted gas at the end of the previous polymerization step include the following methods.
That is, as described above, in the semi-batch polymerization, it is possible to carry out the polymerization pressure at a constant value or to change it at any time during the production of the crystalline propylene polymer, so that the gas concentration of hydrogen and propylene in the unreacted gas As a method for reducing the ratio (H ₂ / C ₃ ), (i) a method in which the supply amount of propylene is kept constant and the supply amount of hydrogen is reduced, and (ii) a supply amount of propylene with a constant polymerization pressure. And (iii) a method of decreasing the supply amount of both propylene and hydrogen, and (iv) a method of increasing the supply amount of both propylene and hydrogen.
In the present invention, from the simplicity of control, (ii) a method of increasing the supply amount of propylene and decreasing the supply amount of hydrogen while keeping the polymerization pressure constant, that is, the ratio of hydrogen to propylene supplied to the reactor. A method in which (H ₂ / C ₃ ) is gradually decreased is preferable.
In batch polymerization, most of the required amount is charged before production, and the hydrogen consumption rate is adjusted, so that the gas concentration ratio of hydrogen to propylene (H ₂ / C ₃ ) in the unreacted gas is 0.1. It can control so that it may become below molar ratio.

  The consumption of hydrogen varies depending on the catalyst, the presence or absence of a polymerization additive, the polymerization time, etc., but in order to keep the hydrogen concentration at the end of production of the linear propylene polymer low, it is preferable that the consumption rate of hydrogen is larger. . From the viewpoint of the consumption rate of hydrogen, a Ziegler catalyst is generally preferable to a metallocene catalyst, and among Ziegler catalysts, a titanium trichloride type is more preferable than a so-called magnesium chloride-supported catalyst.

In this way, the amount of hydrogen is controlled, and at the end of the previous polymerization step (a), the gas concentration ratio of hydrogen to propylene (H ₂ / C ₃ ) in the unreacted gas is preferably 0.1 molar ratio or less. More preferably, the molar ratio is 0.09 or less, and further preferably 0.08 or less. Within this range, it is possible to suppress the introduction of hydrogen into the subsequent linear ethylene / propylene random copolymer production process, and it is easy to obtain a highly viscous copolymer.

  As for the supply timing of hydrogen necessary for the linear propylene polymer, it is preferable to charge most of the necessary amount before production. Further, during the semi-batch polymerization, the amount of hydrogen supplied to propylene can be gradually reduced. By doing so, the average residence time of hydrogen can be made longer than the average residence time in the reactor of propylene, hydrogen can be used more efficiently, and the supply amount can be reduced. As a result, the hydrogen concentration can finally be kept low. Further, hydrogen may be supplied at the end of propylene polymerization, or supply may be stopped. When the hydrogen supply is stopped, the supply may be stopped simultaneously with the end of the propylene polymerization, or the supply may be stopped in the middle of the polymerization.

(Ix) Production of linear ethylene / propylene random copolymer portion In the previous polymerization step (a), propylene was continuously supplied to produce a linear propylene polymer, and the reactor gas was purged once. Subsequently, in the subsequent polymerization step (b), a linear ethylene / propylene random copolymer portion is produced.
In the subsequent polymerization step (b), propylene, ethylene and hydrogen are continuously supplied, and propylene is present in the presence of the catalyst (the catalyst used in the previous polymerization step (a) (first step)). And ethylene are randomly copolymerized to produce a linear ethylene / propylene random copolymer portion, and a linear propylene / ethylene block copolymer is obtained as a final product.

  At this time, the ratio of the first normal stress difference and the shear stress in the melt viscoelasticity measurement of the linear propylene / ethylene block copolymer (component A-1) of the present invention needs to be 1.01 or more. Therefore, although depending on the type of process and catalyst, it is preferable to adjust the hydrogen of the chain transfer agent to a relatively low concentration.

  In the production of the linear ethylene / propylene random copolymer, hydrogen is not supplied in principle, but a small amount can be supplied for the purpose of finely adjusting the viscosity of the resulting propylene / ethylene random copolymer.

  Further, at the time of production of the linear ethylene / propylene random copolymer portion, it is preferable that the supply amount of propylene is decreased with time, while the supply amount of ethylene is supplied while being increased with time. By doing so, the intrinsic viscosity of the propylene / ethylene random copolymer portion can be increased, and the ratio between the first normal stress difference and the shear stress can be easily increased to 1.01 or more. This is because the chain transfer agent hydrogen is brought in somewhat from the polymerization step (a) to the polymerization step (b), but is consumed at the beginning of the polymerization step (b), and the ethylene concentration in the latter stage of polymerization where there is almost no hydrogen. It is considered that the increase in the intrinsic viscosity is possible because the polymerization reaction rate with respect to the chain transfer reaction rate is increased due to the increase.

  The linear propylene polymer portion is preferably a propylene homopolymer from the viewpoint of the rigidity of the linear polypropylene resin composition of the present invention, but from the viewpoint of moldability, propylene and a small amount of a comonomer are included. A copolymer may also be used. Specific examples of the copolymer include α- other than propylene such as ethylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, and 4-methyl 1-pentene. A comonomer unit corresponding to one or more comonomers selected from the group consisting of olefin, styrene, vinylcyclopentene, vinylcyclohexane, vinylnorbornane and the like is preferably contained in a content of 5% by weight or less. Two or more of these comonomers may be copolymerized. The comonomer is preferably ethylene and / or 1-butene, most preferably ethylene. Here, the content of the comonomer unit is a value determined by infrared spectroscopy (IR).

Following the polymerization of the linear propylene polymer portion, the linear ethylene / propylene random copolymer portion is polymerized. The linear ethylene / propylene random copolymer portion is preferably a high molecular weight linear ethylene / propylene random copolymer in order to adjust the die swell ratio and molecular weight distribution (Q value) to predetermined values.
The polymerization of the linear ethylene / propylene random copolymer portion is preferably performed in a hydrogen atmosphere as low as possible or in a state substantially free of hydrogen in order to polymerize a high molecular weight polymer. The polymerization is carried out successively in the presence of the propylene polymer produced in the linear propylene polymer partial polymerization step and a catalyst. The polymerization temperature is usually selected from the range of 40 to 90 ° C. and the pressure of 2 × 10 ^{5 to} 35 × 10 ⁵ Pa.

(2) Physical property (i):
MFR (230 degreeC, 2.16kg load) of the linear propylene polymer part of the component A-1 used for this invention is 130 g / 10min or more, Preferably it is 250-3000 g / 10min, More preferably, it is 550-500. 2000 g / 10 min. When the MFR is less than 130 g / 10 min, the surface appearance and the injection foam moldability of the linear polypropylene resin composition and the injection foam molded article are deteriorated.
The MFR is the MFR when the polymerization of the linear propylene polymer portion is completed, and when performing the multistage polymerization, the MFR is the MFR of the linear propylene polymer portion taken out from the final polymerization tank.

Characteristic (ii):
The component ratio of the linear ethylene / propylene random copolymer portion of the component A-1 used in the present invention to the entire component A-1 is 2 to 50% by weight, preferably 5 to 40% by weight, More preferably, it is 7 to 20% by weight. That is, the ratio of the linear propylene polymer portion to the whole component A-1 is 50 to 98% by weight, preferably 60 to 95% by weight, more preferably 80 to 93% by weight. When the linear ethylene / propylene random copolymer part is less than 2% by weight (that is, the linear propylene polymer part exceeds 98% by weight), the linear polypropylene resin composition and the injection-foamed molded article The injection foaming moldability and impact strength are deteriorated. On the other hand, if the proportion of the linear ethylene / propylene random copolymer portion exceeds 50% by weight (that is, the linear propylene polymer portion is less than 50% by weight), the surface appearance, injection foam moldability and rigidity Gets worse.

Characteristic (iii):
The MFR (230 ° C., 2.16 kg load) of component A-1 used in the present invention needs to exceed 60 g / 10 minutes, preferably 70 g / 10 minutes or more, more preferably 100 g / 10 minutes or more, Preferably it is 150-500 g / 10min. When the MFR is 60 g / 10 min or less, the surface appearance and the injection foam moldability of the polypropylene resin composition and the injection foam molded article are deteriorated. For example, the mold cavity clearance before foaming is about 1 to 2 mm. In molding having a portion, there may occur a case where short shot occurs and stable molding cannot be performed.

Characteristic (iv):
The die swell ratio of the whole component A-1 used in the present invention is 1.2 to 2.5, preferably 1.3 to 2.4, and more preferably 1.4 to 2.3. When the die swell ratio is less than 1.2, the linear propylene-based resin composition cannot maintain a good cell shape at a high magnification, and the injection foam moldability deteriorates. On the other hand, those having a die swell ratio exceeding 2.5 are difficult to manufacture industrially and thus have little practicality.

Characteristic (v):
Component A-1 used in the present invention exhibits strain hardening in 180 ° C. extensional viscosity measurement. In the linear polypropylene resin composition of the present invention, the effect of exhibiting strain hardening in the 180 ° C. elongational viscosity measurement is due to foam breakage at the molten resin flow front (flow front) during injection molding. This makes it difficult for silver streaks to occur, the surface appearance tends to be beautiful, and it becomes easy to obtain a foamed molded article having uniform fine cells at a high magnification.
The term “strain hardenability” as used herein means that the elongational viscosity gradually increases as the amount of stretch strain of the melt increases. It is a case of increasing.

  Here, as to the method for evaluating strain hardening, any method can be used in principle as long as the uniaxial elongation viscosity can be measured. For example, details of the measuring method and measuring instrument are known: Polymer 42 (2001) 8663 has a method described in the above, but as a preferable measurement method, as a measurement device, Ales (Jig: Extensive Visibility Fixture manufactured by TA Instrument Co., Ltd.) manufactured by Rheometrics, or Melten manufactured by Toyo Seiki Co., Ltd. The method using Rheometer is mentioned.

  The degree of strain hardening is 2.0 or more, more preferably 2.5 or more, particularly preferably 3.0 or more, further preferably 5 in the 180 ° C. extensional viscosity measurement (strain rate: 1.0 / sec). It preferably has a strain hardening degree (λmax) of 0.0 or more. When the strain hardening degree (λmax) is less than 2.0, in the linear polypropylene resin composition and the injection foam molded article of the present invention, silver streaks are likely to occur during injection foam molding, and the surface appearance is deteriorated. In some cases, an injection-foamed molded article having uniform fine bubbles cannot be obtained.

Characteristic (vi):
Component A-1 used in the present invention has a ratio (N1 / SS) of the first normal stress difference (N1) to the shear stress (SS) of 1.01 or more, preferably 1. 3 or more, more preferably 2.0 or more. When N1 / SS is less than 1.01, a good cell shape cannot be maintained, and a high-magnification foamed molded product tends to be not obtained. On the other hand, there is no particular upper limit for N1 / SS, but if N1 / SS exceeds 5, the production becomes extremely difficult, so the practicality is small.

Here, N1 / SS is measured according to the following method.
Using a dynamic viscoelasticity measuring device (“ARES” manufactured by TA Instruments), a steady flow measurement was performed by rotating a cone plate having a diameter of 25 mm and a cone angle of 0.1 radians at a temperature of 180 ° C. and a strain rate of 10 / sec. The shear stress (SS) and the first normal stress difference (N1) are the values at 100 s of the shear stress and the first normal stress difference, respectively.
The first normal stress difference (N1) and the shear stress (SS) represent elastic properties and viscous properties, respectively, during steady flow of the resin or resin composition in the molten state.

Other characteristics:
Component A-1 used in the present invention, the intrinsic viscosity _{[eta] copoly} of linear ethylene-propylene random copolymer portion is preferably 5.3~15.0dl / g, more preferably 6.0 to 14.5 dl / g, more preferably 6.5 to 14.0 dl / g. When the intrinsic viscosity _{[eta] copoly} is less than 5.3 dl / g, there is a possibility that the injection foam molding is deteriorated. On the other hand, when the intrinsic viscosity [η] _copolymer exceeds 15.0 dl / g, the surface appearance and impact strength may be deteriorated.

  In addition, Component A-1 used in the present invention preferably has a ratio (Q value: Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) representing the molecular weight distribution, preferably from 7 to 13. Preferably it is 8-12. If the Q value is less than 7, the linear polypropylene-based resin composition cannot maintain a good cell form, and there is a tendency that a high-magnification foam molded article cannot be obtained. On the other hand, when the Q value exceeds 13, the production becomes extremely difficult.

  The ethylene content of the linear ethylene / propylene random copolymer portion of Component A-1 used in the present invention is preferably 15 to 80% by weight based on the total amount of the linear ethylene / propylene random copolymer. More preferably, it is 20-70 weight%, More preferably, it is 25-45 weight%. When the ethylene content is less than 15% by weight, the injection-foaming moldability and the surface appearance of the linear polypropylene resin composition and the injection-foamed molded article are liable to be lowered. On the other hand, when the ethylene content exceeds 80% by weight, The impact strength tends to decrease.

  Furthermore, the weight average molecular weight (Mw) of the linear ethylene / propylene random copolymer portion of Component A-1 used in the present invention is preferably 1 million or more, more preferably 1.1 million to 8 million, and still more preferably. It is 1.2 million to 7 million, particularly preferably 1.5 to 4 million. If the weight average molecular weight (Mw) of the linear ethylene / propylene random copolymer portion is lower than 1,000,000, the effect of improving the injection foam moldability of the linear polypropylene resin composition tends to be insufficient.

MFR, die swell ratio, Mw, Q value, linear ethylene / propylene random copolymer portion content and ethylene content were measured using MFR meter, cross fractionator, Fourier transform infrared absorption spectrum analysis, gel permeation chromatography ( GPC). Intrinsic viscosity [η] _copy is measured using an Ubbelohde viscometer, and strain hardening in 180 ° C. extensional viscosity measurement is measured using an extensional viscosity meter. The measurement conditions of main items are described in the examples.

(3) Blending ratio The blending ratio of Component A-1 in the linear polypropylene resin composition of the present invention is 30 to 100% by weight, preferably 40 to 100% by weight, based on 100% by weight of Component A. Preferably it is 50 to 100% by weight. When the component A-1 is less than 30% by weight, the surface appearance and injection foam moldability of the linear polypropylene resin composition of the present invention and the injection foam molded article thereof are lowered.

1-2. Other propylene polymers (component A-2)
Other propylene-based polymers (component A-2) used in the present invention are propylene homopolymers, copolymers of propylene and α-olefins such as propylene / ethylene random copolymers and propylene / ethylene block copolymers. Coalescence, and mixtures thereof. Of these, a copolymer of propylene and ethylene is preferable, and a propylene / ethylene block copolymer is particularly preferable.
Component A-2 has a feature that contributes to maintaining and improving physical properties such as surface appearance, injection foam moldability, rigidity, impact strength, and productivity in the linear polypropylene resin composition of the present invention. .

(1) Production The production method of the other propylene polymer (component A-2) used in the present invention is not particularly limited, and is appropriately selected from known methods and conditions.
As the propylene polymerization catalyst, a highly stereoregular catalyst is usually used, and examples thereof include a Ziegler catalyst and a metallocene catalyst.
In the presence of the catalyst, it is obtained by applying a production process such as a gas phase polymerization method, a liquid phase bulk polymerization method, or a slurry polymerization method.
Examples of the α-olefin in the propylene / α-olefin copolymer include α-olefins having 2 to 20 carbon atoms excluding propylene, and examples thereof include ethylene, butene-1, hexene-1, and octene-1. The α-olefin copolymerized with propylene may be used alone or in combination of two or more. Of these, ethylene and butene-1 are preferred.

(2) Physical properties The MFR (230 ° C., 2.16 kg load) of Component A-2 used in the present invention is preferably 0.1 to 300 g / 10 minutes, more preferably 3 to 200 g / 10 minutes, and still more preferably. 10 to 100 g / 10 min, particularly preferably 20 to 60 g / 10 min. If the MFR is less than 0.1 g / 10 min, the surface appearance and injection foam moldability of the linear polypropylene resin composition and the injection foamed molded product tend to deteriorate, for example, a mold cavity before foaming In molding having a thin portion with a clearance of about 1 to 2 mm, a short shot may occur and stable molding cannot be performed.

(3) Blending ratio The blending ratio of Component A-2 used in the present invention is 0 to 70% by weight, preferably 0 to 60% by weight, particularly preferably 0 to 50% by weight, based on 100% by weight of Component A. It is. When component A-2 exceeds 70% by weight, the surface appearance and the injection foam moldability of the linear polypropylene resin composition of the present invention and the injection foam molded article thereof are lowered.

2. Foaming agent (component B)
The foaming agent (component B) used in the present invention is a chemical foaming agent, a physical foaming agent, a microcapsule, and the like. In a linear polypropylene resin composition, good injection foam moldability (surface tension, foaming ratio, It is used for the purpose of expressing cell morphology.

(1) Types, functions, etc. Examples of the foaming agent include chemical foaming agents, physical foaming agents, and microcapsules, and any foaming agent can be used without particular limitation as long as it can be normally used for injection foam molding. These foaming agents can be used alone or in admixture of two or more.
Examples of the chemical foaming agent include inorganic chemical foaming agents such as sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, ammonium nitrite, azodicarbonamide (ADCA), N, N′-dinitrosopentamethylenetetramine. Organic chemical blowing agents such as benzenesulfonyl hydrazide and 4,4′-diphenyldisulfonyl azide.

  These chemical foaming agents include organic acids such as citric acid that promote gas generation and sodium citrate Such organic acid metal salts can be used and added together, and nucleating agents such as inorganic fine particles such as talc and lithium carbonate can also be added.

  As the chemical foaming agent, an inorganic type is preferable from the viewpoint that a normal injection molding machine can be used safely and uniform fine bubbles are easily obtained in the molded body. As described above, various chemical foaming agents include inorganic and organic types. Preferred examples include sodium bicarbonate, citric acid, sodium citrate, and mixtures of two or more thereof. Preferred are sodium bicarbonate, a combination of sodium bicarbonate and sodium citrate, and a combination of sodium bicarbonate and citric acid.

For example, these chemical foaming agents are processed into particles having an average particle diameter of 1 to 100 μm, and are then applied to the component A or the like at the time of injection foam molding, and then supplied to an injection molding machine or injection molding. In doing so, it is injected from the middle of the cylinder of the injection molding machine or decomposes in the cylinder or the like to generate a gas such as carbon dioxide.
Moreover, a chemical foaming agent can also be used, after granulating as a masterbatch which used the polyolefin resin as the base material from points, such as a handleability, storage stability, and a polypropylene resin. Thereby, contamination of the hopper of the molding machine and adhesion of powder to the surface of the molded body can be suppressed. In this case, it is preferably used as a master batch of polyolefin resin having a concentration of 10 to 50% by weight.
Alternatively, the chemical foaming agent may be added once, and the chemical foaming agent may be decomposed by pelletization, or the chemical foaming agent having a high concentration may be decomposed in advance and the residue may be added. The chemical foaming agent decomposes in the cylinder of the injection molding machine, and the foaming residue can become the foaming nucleating agent.

Examples of the physical foaming agent include inert gas, low-boiling organic solvent vapor, halogen-based inert solvent vapor, and air.
Examples of the inert gas include carbon dioxide, nitrogen, air, argon, helium, neon, and astatine. Examples of the low boiling point organic solvent vapor include methanol, ethanol, propane, butane, and pentane. Examples of the halogen-based inert solvent vapor include dichloromethane, chloroform, carbon tetrachloride, chlorofluorocarbon, and nitrogen trifluoride. Among these, it is preferable to use an inert gas because it is not necessary to use steam, is inexpensive, and has a very low risk of environmental pollution and fire. Among them, carbon dioxide, nitrogen, argon, and helium are preferable. In particular, carbon dioxide and nitrogen are preferable.
Furthermore, the physical foaming agent is preferably in a supercritical state, which has the advantage of facilitating gas melting into the resin.
The physical foaming agent is injected as a gaseous or supercritical fluid into the component A or the like in a cylinder of an injection molding machine, and is dispersed or dissolved. By injecting into a mold, the pressure is released. It functions as a foaming agent.

Microcapsules are obtained by encapsulating a foaming agent (expansion agent) in a shell made of various thermoplastic resins. Examples of the blowing agent (swelling agent) include specific freons such as trichlorofluoromethane, dichlorofluoromethane, and dichlorofluoroethane, alternative freons, hydrocarbons such as n-pentane, isopentane, isobutane, and petroleum ether, Examples thereof include chlorinated hydrocarbons such as methyl chloride, methylene chloride, and dichloroethylene. The average particle size of the microcapsule foaming agent is usually 2 to 50 μm.
These microcapsules are usually supplied to an injection molding machine or the like after being previously mixed with the component A or the like.

  These foaming agents are used in combination with a chemical foaming agent and a physical foaming agent in order to obtain more uniform and fine bubbles in a linear polypropylene resin composition and an injection foamed molded article and to increase the expansion ratio. In particular, it is preferable to use an inorganic chemical foaming agent in combination with carbon dioxide or nitrogen as a physical foaming agent.

(2) Blending ratio The blending ratio of the foaming agent (component B) in the linear polypropylene resin composition of the present invention may be appropriately set in view of the type of foaming agent, foaming ratio, injection foaming molding conditions, and the like. . For example, when using a chemical foaming agent, 0.001-10 weight part is preferable per 100 weight part of component A, More preferably, it is 0.01-8 weight part, More preferably, it is 0.1-5 weight part.
The blending ratio in this case is a substantial concentration of the foaming agent. For example, when a master batch of the foaming agent and the polyolefin resin is used, the blending ratio is calculated based on the concentration of the foaming agent contained in the master batch. When the blending ratio of component B is less than 0.001 part by weight, the linear polypropylene resin composition does not sufficiently foam, whereas when the blending ratio exceeds 10 parts by weight, the linear polypropylene resin composition The mechanical strength such as impact strength of the product and the injection-foamed molded product decreases, secondary foaming phenomenon (the phenomenon that the surface of the injection-foamed molded product swells in a blistering state due to excessive remaining foaming gas), economics, etc. Disadvantageous.
Moreover, when using a physical foaming agent, it sets suitably by adjusting the injection pressure of the gas to be used, for example. If the gas injection pressure is insufficient or excessive, as in the case of the chemical foaming agent, the linear polypropylene resin composition does not sufficiently foam, or the mechanical strength of the injection-foamed molded article And so on.

3. Filler (component C)
In the linear polypropylene resin composition of the present invention, the filler (component C), which is blended as necessary, is an inorganic or organic filler. Component C is used for the purpose of improving the properties of linear polypropylene-based resin compositions and injection-foamed molded articles, such as injection-foaming moldability, physical properties such as rigidity, dimensional stability (reduction of linear expansion coefficient), and environmental adaptability. It is done.

(1) Kind, shape, etc. Specific examples of component C include, for example, inorganic fillers such as silica, diatomaceous earth, barium ferrite, beryllium oxide, pumice, pumice balun and other oxides, aluminum hydroxide, magnesium hydroxide, basic Hydroxides such as magnesium carbonate, carbonates such as calcium carbonate, magnesium carbonate, dolomite, and dawsonite, sulfates or sulfites such as calcium sulfate, barium sulfate, ammonium sulfate, and calcium sulfite, talc, clay, mica, glass fiber, glass Balloons, glass beads, calcium silicate, wollastonite, montmorillonite, bentonite and other silicates, carbon black, graphite, carbon fiber, carbon hollow sphere and other carbons, molybdenum sulfide, boron fiber, zinc borate, metaboron Barium acid, e Examples thereof include calcium oxalate, sodium borate, magnesium oxysulfate, basic magnesium sulfate fiber, potassium titanate fiber, aluminum borate fiber, calcium silicate fiber, calcium carbonate fiber, and various metal fibers.
On the other hand, as the organic filler, for example, shell fiber such as fir shell, wood powder, cotton, jute, paper strip, cellophane piece, aromatic polyamide fiber, cellulose fiber, nylon fiber, polyester fiber, polypropylene fiber, various synthetic fibers, A thermosetting resin powder etc. can be mentioned.

There is no restriction | limiting in particular about the shape of the component C, The thing of any shape, such as a granular form, plate shape, rod shape, fiber shape, and a whisker shape, can be used.
Of these, plate-like, fiber-like, and whisker-like ones are preferable in that the linear propylene resin composition and the injection-foamed molded article of the present invention, which are excellent in balance between dimensional stability and physical properties, can be easily obtained. Moreover, what is marketed as a filler for polymers can use all.
These are often manufactured in the form of compressed soul, pellets (granulated), granules, chopped strands, etc., in addition to the general powder form, with improved handling convenience, etc. Either can be used. Of these, powder, compressed soul, and granule are preferable.

Among the components C, at least one selected from talc, polyester fiber, whisker, glass fiber, carbon fiber, talc, and polyester fiber is a property such as injection foam moldability, dimensional stability, and rigidity, economy. It is preferable in that a linear polypropylene resin composition and an injection-foamed molded article excellent in balance such as properties are easily obtained. Here, for example, a blend of a plurality of different fibers such as a blend of polyester fiber and cotton may be used.
The whisker mentioned here is an ultrafine fiber (generally 2 μmφ or less, particularly 1 μmφ or less) such as basic magnesium sulfate fiber, potassium titanate fiber, aluminum borate fiber, calcium silicate fiber, calcium carbonate fiber, or ultrafine carbon fiber. It is a shape.

Among them, talc having an average particle size of 15 μm or less, preferably 0.5 to 10 μm, particularly preferably 2 to 8 μm is particularly excellent in balance between physical properties such as injection foaming moldability, dimensional stability, rigidity, and economical efficiency. The propylene-based resin composition and the injection-foamed molded article are preferable because they are easily obtained.
This average particle diameter is a value measured using a laser diffraction / scattering particle size distribution analyzer or the like, and examples of the measuring apparatus include Horiba LA-920 type. Further, talc having an average aspect ratio of 4 or more, particularly 5 or more is more preferable. The measurement of the aspect ratio of talc is obtained from the value measured with a microscope or the like.

  These components C are obtained by surface treatment with an organic titanate coupling agent, an organic silane coupling agent, an unsaturated carboxylic acid, or a modified polyolefin grafted with an anhydride thereof, a fatty acid, a fatty acid metal salt, a fatty acid ester, or the like. Alternatively, two or more kinds may be used in combination for surface treatment.

(2) Manufacturing The manufacturing method of these components C is not specifically limited, It manufactures with a well-known various manufacturing method. For example, in the case of talc, a product obtained by mechanically pulverizing a naturally produced product can be obtained by classifying the product once or more precisely.
Examples of the pulverizer include a jaw crusher, a hammer crusher, a roll crusher, a screen mill, a jet pulverizer, a colloid mill, a roller mill, and a vibration mill. These pulverized talcs are wetted once or repeatedly in an apparatus such as a cyclone, cyclone air separator, micro separator, cyclone air separator, sharp cut separator, etc. to adjust to the average particle size shown in the present invention. Or dry classification. After pulverization to a specific particle size, it is preferable to carry out a classification operation with a sharp cut separator.

(3) Blending ratio In the linear polypropylene resin composition of the present invention, the blending ratio of Component C blended as necessary is 1 to 70 parts by weight, preferably 5 parts per 100 parts by weight of Component A. -50 parts by weight, more preferably 10-35 parts by weight. If the blending ratio of component C is less than 1 part by weight, the rigidity and dimensional stability of the linear polypropylene resin composition and the injection-foamed molded product are liable to decrease, whereas if it exceeds 70 parts by weight, the impact strength And the appearance tends to deteriorate. In addition, you may use 2 or more types of component C together.

4). Elastomer (component D)
In the linear polypropylene resin composition of the present invention, the elastomer (component D) blended as necessary is an ethylene / α-olefin copolymer elastomer, etc., and the linear polypropylene resin composition and injection It is used for the purpose of exhibiting high impact strength, excellent dimensional stability, etc. in a foamed molded product.

(1) Kind As component D, for example, ethylene / propylene copolymer elastomer (ethylene propylene rubber; EPR), ethylene / butene copolymer elastomer (EBR), ethylene / hexene copolymer elastomer (EHR), ethylene Ethylene / α-olefin copolymer elastomer such as octene copolymer elastomer (EOR); Ethylene such as ethylene / propylene / ethylidenenorbornene copolymer, ethylene / propylene / butadiene copolymer, ethylene / propylene / isoprene copolymer・ Α-Olefin ・ Diene terpolymer elastomer; Styrene ・ Butadiene ・ Styrene triblock (SBS), Hydrogenated styrene ・ Butadiene ・ Styrene triblock (SEBS), Styrene ・ Isoprene ・ Styrene Block body (SIS), styrene-based elastomers such as hydrogenated products of styrene-isoprene-styrene triblock body (SEPS).
Two or more of these elastomers can be mixed and used.

(2) Production An ethylene / α-olefin copolymer elastomer, an ethylene / α-olefin / diene terpolymer elastomer, and the like are produced by polymerizing each monomer in the presence of a catalyst. Examples of the catalyst include titanium compounds such as titanium halides, organoaluminum-magnesium complexes such as alkylaluminum-magnesium complexes, so-called Ziegler-type catalysts such as alkylaluminum or alkylaluminum chloride, and the like described in WO91 / 04257. A metallocene compound catalyst or the like can be used. As the polymerization method, polymerization can be performed by applying a production process such as a gas phase fluidized bed, a solution method, or a slurry method.

  Styrenic elastomers can be produced by ordinary anionic polymerization methods and polymer hydrogenation techniques.

(3) Physical properties The MFR (190 ° C., 2.16 kg load) of Component D is preferably 0.5 g / 10 min or more.
Considering the automobile member which is the main use of the present invention, those having an MFR in the above range are preferable because a linear polypropylene resin composition and an injection foamed molded article having good impact strength can be obtained in many cases. .

(4) Blending ratio In the linear polypropylene resin composition of the present invention, the blending ratio of Component D blended as necessary is 1 to 50 parts by weight, preferably 5 parts per 100 parts by weight of Component A. It is -45 weight part, More preferably, it is 10-40 weight part. When the blending ratio of component D is less than 1 part by weight, the impact strength and dimensional stability of the linear polypropylene resin composition and the injection-foamed molded article are liable to decrease, while the blending ratio exceeds 50 parts by weight. , The rigidity tends to decrease.

5). Optional additive (component E)
In the linear propylene-based resin composition of the present invention, in addition to the component A, component B, component C, and component D, if necessary, for example, the effects of the present invention can be achieved within a range that does not significantly impair the effects of the present invention. An optional additive component (component E) can be blended for further improving or imparting other effects.
Specifically, light stabilizers such as hindered amines, ultraviolet absorbers such as benzotriazoles, nucleating agents such as sorbitols, colorants such as pigments, antioxidants such as phenols and phosphoruss, nonionics Antistatic agents such as inorganic compounds, antibacterial and antifungal agents such as thiazoles, flame retardants such as halogen compounds, process oils (blending oils), plasticizers, antiionics such as nonionics, Dispersants such as organometallic salts, lubricants such as fatty acid amides, metal deactivators such as nitrogen compounds, nonionic surfactants, polyolefins such as polypropylene other than the above components A to D, polyamides, Examples thereof include thermoplastic resins such as polyester, fillers, and elastomers. These components may be used in combination of two or more, may be added to the composition, may be added to each component, or may be used in combination in each component.

As light stabilizers and ultraviolet absorbers, for example, hindered amine compounds, benzotriazoles, benzophenones and salicylates are used to impart and improve the weather resistance and durability of linear polypropylene resin compositions and injection-foamed molded articles. It is valid.
Specific examples of the hindered amine compound include a condensate of dimethyl succinate and 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine; poly [[6- (1, 1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl] [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene [(2 , 2,6,6-tetramethyl-4-piperidyl) imino]]; tetrakis (2,2,6,6-tetramethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate; tetrakis ( 1,2,2,6,6-pentamethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate; bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebake Bis-2,2,6,6-tetramethyl-4-piperidyl sebacate and the like, and examples of the benzotriazole type include 2- (2′-hydroxy-3 ′, 5′-di-t-butyl) Phenyl) -5-chlorobenzotriazole; 2- (2′-hydroxy-3′-t-butyl-5′-methylphenyl) -5-chlorobenzotriazole, and the like. As the benzophenone series, 2-hydroxy- 4-methoxybenzophenone; 2-hydroxy-4-n-octoxybenzophenone and the like. Examples of the salicylates include 4-t-butylphenyl salicylate; 2,4-di-t-butylphenyl 3 ′, 5′- And di-t-butyl-4′-hydroxybenzoate.

Moreover, as a nucleating agent, for example, inorganic, sorbitol, carboxylic acid metal salt, organic phosphate, etc. are rigid, heat resistance and hardness of linear polypropylene resin composition and injection-foamed molded article, It is effective for imparting and improving injection foam moldability.
Specific examples include talc; silica and the like as inorganic system, and 1,3,2,4-dibenzylidene-sorbitol; 1,3,2,4-di- (p-methyl-benzylidene as sorbitol system. ) Sorbitol; 1,3,2,4-di- (p-ethyl-benzylidene) sorbitol; 1,3,2,4-di- (2 ′, 4′-di-methyl-benzylidene) sorbitol; -P-chlorobenzylidene-2,4-p-methyl-benzylidene-sorbitol; 1,3,2,4-di- (p-propylbenzylidene) sorbitol and the like. -Hydroxy-di-pt-butylbenzoate; sodium benzoate; calcium montanate and the like. (4-t-butylphenyl) phosphate; sodium-2,2′-methylene-bis (4,6-di-t-butylphenyl) phosphate; lithium-2,2′-methylene-bis (4,6 -Di-t-butylphenyl) phosphate and the like.

In addition, as the colorant, for example, inorganic or organic pigments, such as linear polypropylene resin composition and injection-foamed molded article, coloring appearance, appearance, texture, commercial value, weather resistance, durability, etc. It is effective for granting and improving.
Specific examples of the inorganic pigment include titanium oxide; iron oxide (eg, bengara); chromic acid (eg, galvanized lead); molybdic acid; selenide sulfide; ferrocyanide and carbon black. A poorly soluble azo lake; a soluble azo lake; an insoluble azo chelate; a condensable azo chelate; an azo pigment such as other azo chelates; a phthalocyanine pigment such as phthalocyanine blue; a phthalocyanine green; an anthraquinone; a perinone; a perylene; Rake; quinacridone type; dioxazine type; isoindolinone type. Moreover, in order to make a metallic tone or a pearl tone, an aluminum flake; a pearl pigment can be contained. Moreover, dye can also be contained.

As antioxidants, for example, phenol-based, phosphorus-based and sulfur-based antioxidants are used for the heat resistance stability, processing stability, heat aging resistance, etc. of linear polypropylene resin compositions and injection-foamed molded articles. It is effective for granting and improving.
Examples of the phenolic antioxidant include 2,6-di-t-butyl-4-methylphenol; tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl). Propionate] -methane; tris (3,5-di-t-butyl-4-hydroxyphenyl) isocyanurate and the like.
Examples of phosphorus antioxidants include distearyl pentaerythritol diphosphite; tris (2,4-di-t-butylphenyl) phosphite; tris (2-t-butyl-4-methylphenyl) phosphite. For example, fights.
Moreover, as a sulfur type antioxidant, distearyl thiodipropionate etc. are mentioned, for example.

As the antistatic agent, for example, nonionic or cationic antistatic agents are effective for imparting and improving the antistatic property of the linear polypropylene resin composition and the injection foamed molded article.
Specific examples include polyoxyethylene alkylamines; polyoxyethylene alkylamides; polyoxyethylene alkylphenyl ethers; stearic acid monoglycerides; alkyldiethanolamines; alkyldiethanolamides; alkyldiethanolamine fatty acid monoesters;

[II] Production method of linear polypropylene resin composition, production method and use of injection-foamed molded article As the production method of the linear polypropylene resin composition of the present invention, component A, component B, and further required Depending on the condition, component C, component D and component E are blended at the above blending ratio and mixed using various blenders such as V blender and tumbler mixer, mixer, etc. A method, a single-screw extruder, a twin-screw extruder, a Banbury mixer, a roll mixer, a Brabender plastograph, a kneader and a conventional kneading machine such as a kneader, and each of the above components separately (or A method in which a part is blended) and directly supplied to an injection molding machine can be mentioned.

  When selecting a kneading / granulating method, it is usually preferable to knead / granulate using a twin screw extruder. In this kneading and granulation, the above-mentioned components A to E may be kneaded at the same time, and each component is divided to improve performance, for example, first, a part of component A and component C Alternatively, the whole can be kneaded, and then the remaining components can be kneaded and granulated. In addition, when all or part of component B is mixed and kneaded in the injection foam molding stage, kneading and granulating is performed only with the component excluding all or part of component B.

The injection foam molding method for producing the injection foam molded article in the present invention is not particularly limited, and usually includes a foam molding method using an injection molding machine or an injection compression molding machine.
As an injection foam molding method, for example, in a mold cavity, a linear polypropylene-based resin composition containing at least part of component B is injected and filled while reversing the movable mold at a pressure equal to or higher than the foaming pressure, There is a method in which after the skin layer is formed, the core layer is foamed by further retracting the movable mold after completion of the filling.

  Further, for example, a linear polypropylene resin composition composed of components excluding all or part of component B is supplied to an injection molding machine, and component B such as the physical foaming agent is also compressed or supercritical. In this state, in addition to the direct molding machine, it can be injected into a mold to form an injection foam molding. That is, a linear polypropylene resin composition containing a chemical foaming agent is supplied to an injection molding machine, and at the same time, a physical foaming agent is directly controlled and introduced into the molding machine for molding. This method can also be used in a molding method in which the skin layer is formed by injection filling while retracting the movable mold, and then the core layer is foamed by retracting the movable mold.

Further, for example, the mold is composed of a fixed mold and a movable mold that can move forward and backward, and an initial mold cavity clearance (T ₁ ) that is smaller than the mold cavity clearance (T ₁ ) corresponding to the shape position of the final product. An injection step of injecting and filling a linear or polypropylene-based resin composition in a molten or semi-molten state into a mold cavity having T ₀ ), and retracting the movable mold to the mold cavity clearance (T ₁ ) (core back) And a mold opening injection foaming method comprising a foaming step of filling the voids of the mold cavity with the expansion pressure of the foaming agent.
This molding method is preferable because the surface appearance and the injection foam moldability of the linear polypropylene resin composition and the injection foam molded article can be expressed at a high level. Among these, in the molding method, it is preferable that molding is performed under the condition that the injection rate with respect to 100% of the pre-foaming filling volume in the injection process of injection-filling the linear polypropylene resin composition is 20% / second or more, 50 % / Second or more is more preferable, 100% / second or more is further preferable, and 200% / second or more is particularly preferable. The molding method under these conditions can exhibit the above-described injection foam moldability and surface appearance at a higher level.

  Moreover, the injection foamed molded article in the present invention has an average cell diameter of preferably 500 μm or less, more preferably 200 μm or less, and a thickness formed on the surface of at least one side of the foam layer, preferably 10 μm or more and 1000 μm or less. More preferably, it has a non-foamed layer of 100 μm or more and 500 μm or less. When the average cell diameter of the foam layer exceeds 500 μm, excellent rigidity tends not to be obtained. In addition, when the thickness of the non-foamed layer is less than 10 μm, the surface is not beautiful and the rigidity tends to decrease, and when it exceeds 1000 μm, it is difficult to obtain light weight.

  Further, the expansion ratio of the injection foamed molded product in the present invention is preferably 2.0 times or more and 10.0 times or less, more preferably 2.5 times or more and 6.0 times or less, and more preferably 3.0 times or more and 6.0 times. The following are particularly preferred: If the expansion ratio is less than 2.0 times, the lightness tends to be difficult to obtain, whereas if the expansion ratio exceeds 10.0 times, the rigidity tends to decrease significantly. The expansion ratio refers to the ratio of the specific gravity of the foamed molded product and the non-foamed molded product that was injection-molded under the same conditions except that no foaming agent was added to the linear polypropylene resin composition of the present invention, and the thickness of the foamed molded product. And the value obtained from the ratio of the initial wall thickness.

  Applications of the linear polypropylene resin composition and the injection-foamed molded article of the present invention include automotive parts, household appliances such as televisions, industrial parts including electronic parts, etc., building material parts, preferably automobile parts, especially trim. Automobile interior parts such as roofing, ceiling material, trunk area, instrument panel and pillar.

Examples The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
The evaluation methods, analysis methods and materials used in the examples are as follows.

1. Evaluation method, analysis method (1) Surface appearance:
(A) Silver streak:
The degree of occurrence of silver streaks in the foamed molded product was evaluated in the following three stages, compared with a separately produced non-foamed molded product.
Same level as non-foamed molded products ...
There are some silver streaks on the surface of the molded body.
The molded product has a lot of silver streaks over the entire surface ...
In this case, ◯ and Δ are levels that are judged to have practicality.

(2) Injection foaming moldability:
(A) Surface tension:
The degree of surface tension of the foamed molded product was evaluated in the following three stages in comparison with a separately produced non-foamed molded product.
Same level as non-foamed molded product
Some irregularities on the surface of the molded body
The molded product has many irregularities on the entire surface ...
In this case, ◯ and Δ are levels that are judged to have practicality.

(B) Foaming ratio:
It calculated | required by the board thickness / initial stage thickness of the foaming molding. Cavity clearance after core back / initial cavity clearance = 1.9, 2.7, 3.1 The thickness of the molded body obtained under the condition of each core back amount was evaluated. The evaluation criteria are the following three stages.
However, the initial cavity clearance = 1.3 mm. Accordingly, the cavity clearance after each core back is 2.5, 3.5, 4.0 mm.
The thickness of the entire molded body is exactly the same as the cavity clearance after the core back.
There are some places where the thickness of the molded product is partially thinner than the cavity clearance after the core back.
The thickness of the molded body is generally thinner than the cavity clearance after the core back.
In this case, ◯ and Δ are levels that are judged to have practicality.

(C) Cell form:
The micrograph of the cross section which cut | disconnected the foaming molding in the thickness direction was observed visually, and was evaluated. The evaluation criteria are the following three stages.
The cell diameter is fine and uniform throughout.
Cell diameter is small and partly non-uniform.
Cell diameter is non-uniform throughout or completely peeled
In this case, ◯ and Δ are levels that are judged to have practicality.

(3) Rigidity:
The following bending test was performed to determine the load value (N) when the strain amount was 10 mm. The greater the load value (N), the higher the rigidity.
Test equipment: Shimadzu Autograph AG1000
Support base: span = 100 mm, tip radius of support portion = 10 mm
Indenter: Tip radius = 10 mm
Test piece: Cut piece (50 mm x 150 mm x wall thickness) from a molded product having a foam wall thickness (2.5 mm, 3.5 mm)
Test speed: 50 mm / min Test temperature: 23 ° C.

(4) MFR:
Conforms to JIS K7210. Test temperature: 230 ° C., load: 2.16 kg. However, component D has a test temperature of 190 ° C. and a load of 2.16 kg.

(5) Content of linear ethylene / propylene random copolymer portion and ethylene content:
(A) Analyzer used:
(A-1) Cross sorter:
Diamond Instruments CFC T-100 (hereinafter abbreviated as CFC)
(A-2) Fourier transform infrared absorption spectrum analysis:
FT-IR, Perkin Elmer 1760X
The fixed wavelength infrared spectrophotometer attached as the CFC detector is removed, and an FT-IR is connected instead, and this FT-IR is used as the detector. The transfer line from the outlet of the solution eluted from the CFC to the FT-IR is 1 m long, and the temperature is maintained at 140 ° C. throughout the measurement. The flow cell attached to the FT-IR has an optical path length of 1 mm and an optical path width of 5 mmφ, and the temperature is maintained at 140 ° C. throughout the measurement.
(A-3) Gel permeation chromatography (GPC):
The GPC column in the latter part of the CFC is used by connecting three AD806MS manufactured by Showa Denko KK in series.

(B) CFC measurement conditions:
(B-1) Solvent: Orthodichlorobenzene (ODCB)
(B-2) Sample concentration: 4 mg / mL
(B-3) Injection amount: 0.4 mL
(B-4) Crystallization: The temperature is lowered from 140 ° C. to 40 ° C. over about 40 minutes.
(B-5) Sorting method:
The fractionation temperature at the time of temperature-raising elution fractionation is 40, 100, and 140 ° C., and fractionation is performed in three fractions in total. In addition, the elution ratio (unit:% by weight) of the component eluting at 40 ° C. or lower (fraction 1), the component eluting at 40 to 100 ° C. (fraction 2), and the component eluting at 100 to 140 ° C. (fraction 3), respectively W ₄₀ , W ₁₀₀ , and W ₁₄₀ are defined. W ₄₀ + W ₁₀₀ + W ₁₄₀ = 100. Moreover, each fractionated fraction is automatically transported to the FT-IR analyzer as it is.
(B-6) Solvent flow rate during elution: 1 mL / min

(C) FT-IR measurement conditions:
After elution of the sample solution starts from GPC at the latter stage of CFC, FT-IR measurement is performed under the following conditions, and GPC-IR data is collected for each of the above-described fractions 1 to 3.
(C-1) Detector: MCT
(C-2) Resolution: 8 cm ⁻¹
(C-3) Measurement interval: 0.2 minutes (12 seconds)
(C-4) Number of integrations per measurement: 15 times

(D) Post-processing and analysis of measurement results:
The elution amount and molecular weight distribution of the components eluted at each temperature are determined using the absorbance at 2945 cm ⁻¹ obtained by FT-IR as a chromatogram. The elution amount is normalized so that the total elution amount of each elution component is 100%. Conversion from the retention volume to the molecular weight is performed using a standard curve prepared in advance by standard polystyrene.
The standard polystyrenes used are all the following brands manufactured by Tosoh Corporation.
F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000.

A calibration curve is created by injecting 0.4 mL of a solution dissolved in ODCB (containing 0.5 mg / mL BHT) so that each is 0.5 mg / mL. The calibration curve uses a cubic equation obtained by approximation by the least square method. Conversion to molecular weight uses a general-purpose calibration curve with reference to “Size Exclusion Chromatography” written by Sadao Mori (Kyoritsu Shuppan). The following numerical values are used in the viscosity equation ([η] = K × M ^α ) used at that time.
(D-1) When creating a calibration curve using standard polystyrene:
K = 0.000138, α = 0.70
(D-2) During sample measurement of component A-1:
K = 0.000103, α = 0.78
The ethylene content distribution (distribution of ethylene content along the molecular weight axis) of each eluted component is a ratio of the absorbance of 2956 cm ⁻¹ and the absorbance of 2927 cm ⁻¹ obtained by FT-IR, and is obtained by using polyethylene, polypropylene, or ¹³ Converted to ethylene content (% by weight) using a calibration curve prepared in advance using ethylene-propylene rubber (EPR) and mixtures thereof whose ethylene content is known by C-NMR measurement, etc. Ask.

(E) Content of linear ethylene / propylene random copolymer portion:
The content (Wc) of the ethylene / propylene random copolymer portion in Component A-1 used in the present invention is theoretically defined by the following formula (I), and is determined by the following procedure.
Wc (% by weight) = W ₄₀ × A ₄₀ / B ₄₀ + W ₁₀₀ × A ₁₀₀ / B ₁₀₀ (I)
In the formula (I), W ₄₀ and W ₁₀₀ are elution ratios (unit:% by weight) in each of the above-described fractions, and A ₄₀ and A ₁₀₀ are actual values in the respective fractions corresponding to W ₄₀ and W _100. The measured average ethylene content (unit: wt%), and B ₄₀ and B ₁₀₀ are the ethylene content (unit: wt%) of the linear ethylene / propylene random copolymer portion contained in each fraction. . A method for _obtaining A ₄₀ , A ₁₀₀ , B ₄₀ , and B ₁₀₀ will be described later.

The meaning of the formula (I) is as follows. That is, the first term on the right side of the formula (I) is a term for calculating the amount of the linear ethylene / propylene random copolymer portion contained in the fraction 1 (portion soluble at 40 ° C.). When fraction 1 contains only a linear ethylene / propylene random copolymer and no linear propylene polymer, W ₄₀ is the linear ethylene / propylene random derived from fraction 1 as it is Fraction 1 contributes to the copolymer content, but in addition to the component derived from the linear ethylene / propylene random copolymer, a small amount of the component derived from the linear propylene polymer (component with extremely low molecular weight) And atactic polypropylene), it is necessary to correct the portion. Therefore, by multiplying W ₄₀ by A ₄₀ / B ₄₀ , the amount derived from the linear ethylene / propylene random copolymer portion in fraction 1 is calculated. For example, when the average ethylene content (A ₄₀ ) of fraction 1 is 30% by weight and the ethylene content (B ₄₀ ) of the linear ethylene / propylene random copolymer contained in fraction 1 is 40% by weight In the fraction 1, 30/40 = 3/4 (ie, 75% by weight) is derived from a linear ethylene / propylene random copolymer, and 1/4 is derived from a linear propylene polymer. Thus, the operation of multiplying A40 / B40 in the first term on the right side means that the contribution of the linear ethylene / propylene random copolymer is calculated from the weight% (W ₄₀ ) of fraction 1. The same applies to the second term on the right side. For each fraction, the linear ethylene / propylene random copolymer partial content is calculated by adding the contribution of the linear ethylene / propylene random copolymer. .

(E-1) As described above, the average ethylene contents corresponding to fractions 1 and 2 obtained by CFC measurement are A ₄₀ and A ₁₀₀ , respectively (unit is weight%). A method for obtaining the average ethylene content will be described later.

(E-2) The ethylene content corresponding to the peak position in the differential molecular weight distribution curve of fraction 1 is defined as B ₄₀ (unit is% by weight). Fraction 2 is considered to be substantially defined as B ₁₀₀ = 100 in the present invention because it is considered that the rubber part is completely eluted at 40 ° C. and cannot be defined with the same definition. B ₄₀ and B ₁₀₀ are the ethylene content of the linear ethylene / propylene random copolymer portion contained in each fraction, but it is practically impossible to obtain this value analytically. This is because there is no means for completely separating and fractionating the linear propylene polymer and the linear ethylene / propylene random copolymer mixed in the fraction.
As a result of investigations using various model samples, B ₄₀ can explain the effect of improving material properties well by using the ethylene content corresponding to the peak position of the differential molecular weight distribution curve of fraction 1. all right. Further, B ₁₀₀ has crystallinity derived from ethylene chain, and the amount of linear ethylene / propylene random copolymer contained in these fractions includes linear ethylene / propylene random copolymer contained in fraction 1. For the two reasons that it is relatively small compared to the amount of coalescence, the approximation to 100 is closer to the actual situation and hardly causes an error in calculation. Therefore, analysis is performed with B ₁₀₀ = 100.

(E-3) For the above reason, the content (Wc) of the linear ethylene / propylene random copolymer portion is determined according to the following formula.
Wc _{(wt%) = W 40 × A 40} / B 40 + W 100 × A 100/100 ... (II)
That is, W ₄₀ × A ₄₀ / B ₄₀ which is the first term on the right side of the formula (II) indicates the content (wt%) of the linear ethylene / propylene random copolymer having no crystallinity, and the second term. W ₁₀₀ × A _100/100 is a linear ethylene / propylene random copolymer partial content (% by weight) having crystallinity.
_Here, the average ethylene content _A 40 of _{B 40} and each of the fractions obtained by the CFC measurement 1 and _{2, A 100} is determined as follows.
Ethylene content corresponding to the peak position of the differential molecular weight distribution curve is B _40. In addition, the sum of the products of the weight ratio for each data point and the ethylene content for each data point, which is captured as data points during measurement, is the average ethylene content A _{40 of} fraction 1. The average ethylene content A _{100 of} fraction 2 is determined in the same manner.

The significance of setting the three types of fractionation temperatures is as follows. In the CFC analysis of the present invention, a polymer having no crystallinity at 40 ° C. (for example, most of the linear ethylene / propylene random copolymer or extremely low molecular weight in the linear propylene polymer portion) It has the meaning that it is a temperature condition necessary and sufficient for fractionating only the component and the atactic component). 100 ° C. means a component that is insoluble at 40 ° C. but becomes soluble at 100 ° C. (for example, a component having crystallinity due to a chain of ethylene and / or propylene in a linear ethylene / propylene random copolymer) , And a linear propylene polymer having low crystallinity). 140 ° C. means a component that is insoluble at 100 ° C. but becomes soluble at 140 ° C. (for example, a component having particularly high crystallinity in a linear propylene polymer and a linear ethylene / propylene random copolymer) The temperature is necessary and sufficient to elute only the component having extremely high molecular weight and extremely high ethylene crystallinity and recover the entire amount of propylene / ethylene block copolymer used for analysis. W ₁₄₀ does not contain any linear ethylene / propylene random copolymer portion, or even if it is present, it is extremely small amount and can be substantially ignored. It is excluded from the calculation of the content of the polymer and the ethylene content of the linear ethylene / propylene random copolymer.

(F) Ethylene content of linear ethylene / propylene random copolymer portion:
The ethylene content of the linear ethylene / propylene random copolymer portion in Component A-1 used in the present invention is determined from the following formula using the values described above.
Ethylene content (% by weight) of linear ethylene / propylene random copolymer portion = (W ₄₀ × A ₄₀ + W ₁₀₀ × A ₁₀₀ ) / Wc
[Wc is the ratio (% by weight) of the linear ethylene / propylene random copolymer portion determined previously. ]

(6) Intrinsic viscosity [η] _{copy of the} linear ethylene / propylene random copolymer portion:
The intrinsic viscosity [eta] _copoly of linear ethylene-propylene random copolymer portion in the component A-1 used in the present invention is determined as follows.
First, after completion of the polymerization of the linear propylene polymer part, a part is sampled from the polymerization tank, and the intrinsic viscosity [η] _{homo of the part} is measured. Next, after polymerizing the linear propylene polymer portion, the intrinsic viscosity [η] _F of the final polymer (F) obtained by polymerizing the linear ethylene / propylene random copolymer portion is measured. This measurement is performed at a temperature of 135 ° C. using decalin as a solvent using an Ubbelohde viscometer. [Η] _copy is obtained from the following relationship.
[Η] _F = (100−Wc) / 100 × [η] _homo + Wc / 100 × [η] _copy

(7) Die swell ratio:
The die swell ratio of component A-1 used in the present invention is a value determined by the following method.
Set the in-cylinder temperature of the MFR meter to 190 ° C. The orifice has a length of 8.00 mm, a diameter of 1.00 mmφ, and L / D = 8. Also, place a graduated cylinder containing ethyl alcohol directly under the orifice (the distance between the orifice and the ethyl alcohol liquid surface is 20 ± 2 mm). In this state, the sample is put into the cylinder, and the load is adjusted so that the extrusion amount per minute becomes 0.10 ± 0.03 g. The extrudate after 6 to 7 minutes is dropped into ethanol and solidified before being collected. The maximum and minimum values of the diameter of the strand-shaped sample of the collected extrudate were measured at 3 locations, 1 cm from the top, 1 cm from the bottom, and the center. Ratio.
The die swell ratio of component A is determined by, for example, performing polymerization in a hydrogen atmosphere of as low a concentration as possible or in the absence of hydrogen at the time of polymerization of the constituent linear ethylene / propylene random copolymer portion. It is possible to adjust by controlling the height of the high.

(8) Strain hardenability:
The strain hardening property of Component A-1 used in the present invention is measured by the following method.
(A) Apparatus: Ales manufactured by Rheometrics
(B) Jig: EXTENSIONAL VISUALITY FIXTURE, manufactured by TA Instruments
(C) Test temperature: 180 ° C
(D) Strain rate: 1.0 / sec
(E) Sample test piece: press molded sheet of 15 mm × 10 mm, thickness 0.5 mm

(F) Determination of the presence or absence of strain hardening:
The elongational viscosity at a strain rate of 1.0 / sec is plotted as a logarithmic graph of the amount of strain on the horizontal axis and the elongational viscosity ηE (Pa · s) on the vertical axis. As the amount of strain increases, the extensional viscosity gradually increases, and when the rate of increase in the extensional viscosity increases abruptly from a certain amount of strain, this is a case where strain hardening is exhibited. The case was made “strain hard”. On the other hand, the case where the above-mentioned phenomenon was not substantially recognized was set as “no strain”.
(G) Calculation method of strain hardening degree (λmax):
On the above logarithmic graph, the viscosity immediately before the strain hardening is approximated by a straight line, and the maximum value (ηmax) of the elongational viscosity η _E until the strain amount becomes 4.0 is obtained. Let ηlin be the viscosity on the approximate straight line. ηmax / ηlin is defined as λmax.
The strain rate can be measured in the range of 0.001 / sec to 10.0 / sec, and the strain hardening degree varies depending on the difference in strain rate.

(9) Q value (Mw / Mn):
The Q value of the component A-1 used in the present invention is the molecular weight distribution curve of the entire component A prepared by synthesizing the molecular weight distribution curves of the fractions 1 to 3 measured by gel permeation chromatography in the above-described cross fractionator. Ask more. The method for calculating the weight average molecular weight (Mw) and the number average molecular weight (Mn) from this molecular weight distribution curve is according to a known method, and Mw / Mn is used as the Q value.

(10) Shear stress (SS) and first normal stress difference (N1):
The ratio (N1 / SS) of the first normal stress difference (N1) and the shear stress (SS) of component A-1 used in the present invention is a dynamic viscoelasticity measuring device (“ARES” manufactured by TA Instruments). , A cone plate with a diameter of 25 mm and a cone angle of 0.1 radians was rotated at a temperature of 180 ° C. and a strain rate of 10 / sec. Are the shear stress (SS) and the first normal stress difference (N1), respectively.

2. Material (1) Component A (Component A-1)
Production Example 1 (Component A-1a):
I. Production of solid catalyst component (a) 20 liters of dehydrated and deoxygenated n-heptane and 20 liters of MgCl ₂ , Ti (On -C ₄ H _{9) 4} and 20 mol introduced and reacted for 2 hours at 95 ° C.. After completion of the reaction, the temperature was lowered to 40 ° C., and then 12 liters of methylhydropolysiloxane (20 centistokes) was introduced and reacted for 3 hours. The resulting solid component was washed with n-heptane.
Subsequently, 5 liters of dehydrated and deoxygenated n-heptane was introduced into the tank using the tank equipped with a stirrer, and 3 mol of the solid component synthesized above was introduced in terms of Mg atoms. Next, 5 mol of SiCl ₄ was mixed with 2.5 liters of n-heptane, introduced into the flask at 30 ° C. for 30 minutes, and reacted at 70 ° C. for 3 hours. After completion of the reaction, washing with n-heptane was performed.
Next, 2.5 liters of n-heptane was introduced into the tank equipped with a stirrer, 0.3 mol of phthalic acid chloride was mixed, introduced at 70 ° C. for 30 minutes, and reacted at 90 ° C. for 1 hour. After completion of the reaction, washing with n-heptane was performed. Next, 2 liters of TiCl ₄ was introduced and reacted at 110 ° C. for 3 hours. After completion of the reaction, a solid component was obtained. The titanium content of this solid component was 2.0% by weight.
Then purged with nitrogen the stirrer with tank n- heptane 8 liters synthesized solid component above 400 g, and allowed to react for 2 hours at a SiCl ₄ 0.6 liters introduced to 90 ° C.. After completion of the reaction, further _{(CH 2 = CH) Si (} CH 3) 3 0.54 _{mole, (t-C 4 H 9} ) (CH 3) Si (OCH 3) 2 0.27 mol, Al (C ₂ H ₅ ) ₃ was sequentially introduced at 1.5 mol and contacted at 30 ° C. for 2 hours. After completion of the contact, the product was sufficiently washed with n-heptane to obtain 390 g of a solid catalyst component (a) mainly composed of magnesium chloride. The titanium content of this product was 1.8% by weight.

II. Production of propylene-based block copolymer A stainless steel autoclave with a stirrer having an internal volume of 400 liters was sufficiently replaced with propylene gas, and 120 liters of dehydrated and deoxygenated n-heptane was added as a polymerization solvent. Next, 30 g of triethylaluminum, 147 liters of hydrogen, and 17 g of the solid catalyst component (a) were added at a temperature of 70 ° C. After the temperature of the autoclave was raised to an internal temperature of 75 ° C., propylene was supplied so that the pressure became 0.3 MPaG, and polymerization was started. Hydrogen started to be supplied at a hydrogen / propylene ratio of 10.2 (L / Kg), and was reduced at a constant rate so that it would become 0 after 230 minutes. After 230 minutes, the introduction of propylene was stopped, and the unreacted gas in the vessel was released to 0.03 MPaG to obtain a crystalline propylene polymer portion (preliminary polymerization step). The hydrogen concentration (hydrogen / propylene) in the reactor was 0.24 molar ratio at the start of polymerization, but gradually decreased, and 0.08 molar ratio when propylene supply was stopped.
Next, after setting the autoclave at an internal temperature of 65 ° C., 12.5 cc of n-butanol was introduced, and then propylene was reduced at a constant rate so that it became 0 after 120 minutes from the start of feeding at 5.25 Kg / Hr, and ethylene was 0 120 minutes after that, it was supplied at a constant rate so as to be 2.25 Kg / Hr. After 120 minutes, the supply of ethylene and propylene was stopped to complete the polymerization. The pressure was 0.03 MPaG at the start of ethylene and propylene supply, but was 0.01 MPaG when the supply was stopped (the latter polymerization step).
The obtained slurry was transferred to the next tank equipped with a stirrer, 2.5 liters of butanol was added, treated at 70 ° C. for 3 hours, further transferred to the next tank equipped with a stirrer, and 100 g of pure water in which 20 g of sodium hydroxide was dissolved. After adding 1 liter and treating for 1 hour, the aqueous layer was allowed to stand and then separated to remove the catalyst residue. The slurry was treated with a centrifugal separator to remove heptane, and then treated with a dryer at 80 ° C. for 3 hours to completely remove heptane, thereby obtaining a linear propylene / ethylene block copolymer (A-1a).

The linear propylene / ethylene block copolymer (A-1a) has an MFR (230 ° C., 2.16 kg load) of the linear polypropylene polymer portion of 592 g / 10 min, linear ethylene / propylene random copolymer ratio is 9.6 wt% to the whole component a-1a of the united portion, the intrinsic viscosity _{[eta] copoly} of linear ethylene-propylene random copolymer portion 12.8dl / g, component a-1a overall MFR ( 230 ° C., 2.16 kg load) is 105 g / 10 min, the die swell ratio of the whole component A-1a is 1.8, and shows strain hardening in 180 ° C. extensional viscosity measurement (strain hardening “Yes”). The strain hardening degree (λmax) is 7.7, and the ratio of the first normal stress difference (N1) to the shear stress (SS) in the transient response measurement at a strain rate of 180 ° C. of 10 / sec (N1 / SS) Further, the Q value of the whole component A-1a was 14.3, and the ethylene content of the linear ethylene / propylene random copolymer portion was 23.1% by weight (measured by a cross fractionation method). Chain propylene / ethylene block copolymer (antioxidant / neutralizing agent, added pellets).

Production Example 2 (Component A-1b):
In Production Example 1, the supply amount of hydrogen in the first-stage polymerization step was started at a hydrogen / propylene ratio of 13.6 (L / Kg), and decreased at a constant rate so that it became 0 after 230 minutes. The component is reduced at a constant rate so that it becomes 0 120 minutes after the start of supply at 3.75 Kg / Hr, and ethylene is supplied at a constant rate so that it becomes 3.75 Kg / Hr after 0 to 120 minutes. Proceeding according to the production of A-1a, a propylene / ethylene block copolymer (A-1b) was produced. The hydrogen concentration (hydrogen / propylene) in the reactor of the pre-stage polymerization step was 0.07 molar ratio when propylene supply was stopped.

The linear propylene / ethylene block copolymer (A-1b) has a linear propylene polymer portion MFR (230 ° C., 2.16 kg load) of 795 g / 10 min, linear ethylene / propylene random copolymer ratio is 8.7 wt% to the whole component a-1b of the united portion, the intrinsic viscosity _{[eta] copoly} of linear ethylene-propylene random copolymer portion 13.0dl / g, component a-1b overall MFR ( 230 ° C., 2.16 kg load) is 150 g / 10 min, the die swell ratio of the entire component A-1b is 1.9, and shows strain hardening in 180 ° C. extensional viscosity measurement (strain hardening “Yes”). The strain hardening degree (λmax) is 9.1, and the ratio (N1 / SS) of the first normal stress difference (N1) to the shear stress (SS) in the transient response measurement at a strain rate of 180 ° C. of 10 / sec. Further, the linear component having a Q value of the entire component A-1b of 14.1, and an ethylene content of the linear ethylene / propylene random copolymer portion of 40.4% by weight (measured by a cross fractionation method) Propylene / ethylene block copolymer (antioxidant / neutralizing agent, added pellets).

Production Example 3 (Component A-1c):
In Production Example 1, the supply amount of hydrogen was started at 11.0 (L / Kg) of hydrogen / propylene in the pre-stage polymerization step, and decreased at a constant rate to become 0 after 230 minutes. In the post-stage polymerization step, Propylene is reduced at a constant rate so that it becomes 0 120 minutes after the start of supply at 6.3 Kg / Hr, and ethylene is supplied at a constant rate so that it becomes 2.7 Kg / Hr after 0 to 120 minutes. It carried out according to manufacture of component A-1a, and manufactured the propylene ethylene block copolymer (A-1c). The hydrogen concentration (hydrogen / propylene) in the reactor of the pre-stage polymerization process was 0.09 molar ratio when propylene supply was stopped.

The linear propylene / ethylene block copolymer (A-1c) has a linear propylene polymer portion MFR (230 ° C., 2.16 kg load) of 618 g / 10 min, linear ethylene / propylene random copolymer ratio is 11.1% by weight with respect to the entire component a-1c of the united portion, the intrinsic viscosity _{[eta] copoly} of linear ethylene-propylene random copolymer portion 12.5dl / g, component a-1c overall MFR ( 230 ° C., 2.16 kg load) is 75 g / 10 min, the die swell ratio of the whole component A-1c is 1.8, and shows strain hardening in 180 ° C. extensional viscosity measurement (strain hardening “Yes”). The strain hardening degree (λmax) is 7.6, and the ratio (N1 / SS) of the first normal stress difference (N1) to the shear stress (SS) in the transient response measurement at a strain rate of 180 ° C. of 10 / sec. .78, and the total linearity of component A-1c is 13.8, and the ethylene content of the linear ethylene / propylene random copolymer portion is 23.3 wt% (measured by cross fractionation method). Propylene / ethylene block copolymer (antioxidant / neutralizing agent, added pellets).

Production Example 4 (Component A-1d):
I. Production of solid catalyst component (b) 20 liters of dehydrated and deoxygenated n-heptane and 20 liters of MgCl ₂ , Ti (On -C ₄ H ₉ ) ₄ was introduced in an amount of 20 mol and reacted at 95 ° C. for 2 hours. After completion of the reaction, the temperature was lowered to 40 ° C., and then 12 liters of methylhydropolysiloxane (20 centistokes) was introduced and reacted for 3 hours. The resulting solid component was washed with n-heptane.
Subsequently, 5 liters of dehydrated and deoxygenated n-heptane was introduced into the tank using the tank equipped with a stirrer, and 3 mol of the solid component synthesized above was introduced in terms of Mg atoms. Next, 5 mol of SiCl ₄ was mixed with 2.5 liters of n-heptane, introduced into the flask at 30 ° C. for 30 minutes, and reacted at 70 ° C. for 3 hours. After completion of the reaction, washing with n-heptane was performed.
Next, 2.5 liters of n-heptane was introduced into the tank equipped with a stirrer, 0.3 mol of phthalic acid chloride was mixed, introduced at 90 ° C. for 30 minutes, and reacted at 95 ° C. for 1 hour. After completion of the reaction, washing with n-heptane was performed. Next, 2 liters of TiCl ₄ was introduced and reacted at 100 ° C. for 2 hours. After completion of the reaction, washing with n-heptane was performed. Furthermore, TiCl ₄ 0.6 liters, n- heptane was introduced 8 liters 1 hour at 90 ° C., washed thoroughly with n- heptane to obtain a solid component. This solid component contained 1.30% by weight of titanium.
Next, 8 liters of n-heptane in the tank equipped with a stirrer substituted with nitrogen, 400 g of the solid component obtained above, and 0.27 mol of (tC ₄ H ₉ ) (CH ₃ ) Si (OCH ₃ ) ₂ , (CH ₂ ═CH) Si (CH ₃ ) ₃ 0.27 mol was introduced and contacted at 30 ° C. for 1 hour. Next, the mixture was cooled to 15 ° C., and 1.5 mol of Al (C ₂ H ₅ ) ₃ diluted in n-heptane was introduced over 15 minutes under 15 ° C. After the introduction, the temperature was raised to 30 ° C. and reacted for 2 hours. The liquid was taken out and washed with n-heptane to obtain 390 g of a solid catalyst component (b). The titanium content of this product was 1.22% by weight.
Further, 6 liters of n-heptane and 1 mol of triisobutylaluminum diluted in n-heptane were introduced over 30 minutes at 15 ° C., and then about 0.4 kg of propylene was controlled so as not to exceed 20 ° C. Per hour for 1 hour to conduct prepolymerization. As a result, a polypropylene-containing solid catalyst component (b) in which 0.9 g of propylene was polymerized per 1 g of solid was obtained.

II. Production of propylene block copolymer Polymerization was carried out using a continuous reaction apparatus comprising two fluidized bed reactors having an internal volume of 230 liters. First, while maintaining a polymerization temperature of 75 ° C. and a propylene partial pressure of 1.8 MPa in the first reactor, hydrogen as a molecular weight control agent is continuously supplied so that the molar ratio of hydrogen / propylene is 0.055. Then, triethylaluminum was supplied at 5.25 g / hr and the solid catalyst component (b) containing polypropylene was supplied so that the polymer polymerization rate was 20 kg / hr to produce a crystalline propylene polymer component. The powder polymerized in the first reactor (crystalline propylene polymer component) was continuously withdrawn so that the amount of powder held in the reactor was 60 kg and transferred to the second reactor.
Subsequently, propylene and ethylene are continuously fed so that the molar ratio of ethylene / (propylene + ethylene) is 0.30 so that the inside of the second reactor has a polymerization temperature of 80 ° C. and a pressure of 2.0 MPa. Furthermore, hydrogen as a molecular weight control agent is continuously supplied so that the molar ratio of hydrogen / (propylene + ethylene) is 0.015, and ethyl alcohol is added as an active hydrogen compound to triethylaluminum. The propylene / ethylene random copolymer component was produced by supplying 1.4 mol.
The powder that has been polymerized in the second reactor (a propylene-based block copolymer comprising a crystalline propylene polymer component and a propylene / ethylene random copolymer component) has a powder content in the reactor of 40 kg. Continuously extracted into a vessel. Nitrogen gas containing water was supplied to stop the reaction to obtain a propylene / ethylene block copolymer (A-1d).

The linear propylene / ethylene block copolymer (A-1d) has a linear propylene polymer portion MFR (230 ° C., 2.16 kg load) of 150 g / 10 min, linear ethylene / propylene random copolymer ratio is 27.0% by weight to the whole component a of the united portion, the intrinsic viscosity _{[eta] copoly} of linear ethylene-propylene random copolymer portion is 2.9 dl / g, component a-1d overall MFR (230 ° C. , 2.16 kg load) is 30 g / 10 min, the die swell ratio of the entire component A-1d is 1.0, and does not exhibit strain hardening in the 180 ° C. elongational viscosity measurement (strain hardening “no”). The strain hardening degree (λmax) cannot be calculated, and the ratio (N1 / SS) of the first normal stress difference (N1) to the shear stress (SS) in the transient response measurement at a strain rate of 180 ° C. of 10 / sec is 0.98. In addition, the Q value of the whole component A-1d is 6.0, and the ethylene content of the linear ethylene / propylene random copolymer portion is 37% by weight (measured by a cross fractionation method). Combined (antioxidant / neutralizing agent, added pellets).

Production Example 5 (Component A-1e):
A stainless steel autoclave with a stirrer having an internal volume of 400 liters was sufficiently replaced with propylene gas, and 120 liters of dehydrated and deoxygenated n-heptane was added as a polymerization solvent. Next, 30 g of triethylaluminum, 70 liters of hydrogen, and 15 g of a solid catalyst component (b) containing polypropylene were added under a temperature of 70 ° C. After the autoclave was heated to an internal temperature of 75 ° C., propylene was supplied at a rate of 16.6 kg / hour and hydrogen was supplied at a rate of 50.0 L / hour to initiate polymerization. After 230 minutes, the introduction of propylene and hydrogen was stopped. The pressure was 0.34 kg / cm ² G at the start of polymerization, increased with time during the supply of propylene, and increased to 3.9 kg / cm ² G when the supply was stopped. Then, after the pressure in the vessel is subjected to residual polymerization until drops to 3.5 kg / cm ² G, and releasing the unreacted gas to 0.3 kg / cm ^2. During this time, the polymerization temperature was maintained in the range of 75 ± 1 ° C. (one-stage polymerization).
Next, after setting the autoclave to an internal temperature of 65 ° C., 16.0 cc of n-butanol was introduced, and then propylene was fed at 3.3 kg / hour and ethylene was fed at a rate of 2.4 kg / hour to start two-stage polymerization. did. After 120 minutes, the introduction of propylene and ethylene was stopped. The pressure increased with time during the supply of propylene and ethylene, and increased to 0.5 kg / cm ² G when the supply was stopped. Thereafter, the unreacted gas in the vessel was released to 0.3 kg / cm ² . During this time, the polymerization temperature was maintained in the range of 65 ± 1 ° C. (two-stage polymerization).
The obtained slurry was transferred to the next tank with a stirrer, 5 liters of butanol was added, treated at 70 ° C. for 3 hours, further transferred to the next tank with a stirrer, and 100 liters of pure water in which 100 g of sodium hydroxide was dissolved. In addition, after treating for 1 hour, the aqueous layer was allowed to stand and then separated to remove the catalyst residue. The slurry was treated with a centrifugal separator to remove heptane, and then treated with a dryer at 80 ° C. for 3 hours to completely remove heptane to obtain a propylene / ethylene block copolymer (A-1e).

The linear propylene / ethylene block copolymer (A-1e) has a linear propylene polymer portion MFR (230 ° C., 2.16 kg load) of 130 g / 10 min, linear ethylene / propylene random copolymer ratio is 15.5% by weight with respect to the entire component a-1e of the united portion, the intrinsic viscosity _{[eta] copoly} of linear ethylene-propylene random copolymer portion is 7.1dl / g, component a-1e overall MFR ( 230 ° C., 2.16 kg load) is 30 g / 10 min, the die swell ratio of the whole component A-1e is 1.6, and shows strain hardening in 180 ° C. extensional viscosity measurement (strain hardening “Yes”). The strain hardening degree (λmax) is 2.03, and the ratio (N1 / SS) of the first normal stress difference (N1) to the shear stress (SS) in the transient response measurement at a 180 ° C. strain rate of 10 / sec. In addition, the total propylene component A-1e has a Q value of 8.4, and the ethylene content of the linear ethylene / propylene random copolymer portion is 42% by weight (measured by a cross fractionation method). Ethylene block copolymer (antioxidant / neutralizing agent, added pellets).

Production Example 6 (component A-1f):
In Production Example 4, the hydrogen / propylene molar ratio in the preceding polymerization step was 0.087, the hydrogen / (propylene + ethylene) molar ratio in the latter polymerization step was 0.020, and ethyl alcohol was 1. Except having changed so that it might become 8 times mole, it carried out according to manufacture example 4 and manufactured the propylene ethylene block copolymer (A-1f).

The linear propylene / ethylene block copolymer (A-1f) has a linear propylene polymer portion MFR (230 ° C., 2.16 kg load) of 270 g / 10 min, linear ethylene / propylene random copolymer ratio is 20.3% by weight with respect to the entire component a-1f of the united portion, the intrinsic viscosity _{[eta] copoly} of linear ethylene-propylene random copolymer portion is 2.7 dl / g, component a-1f overall MFR ( 230 ° C., 2.16 kg load) is 103 g / 10 min, the die swell ratio of the entire component A-1f is 1.0, and does not show strain hardening in 180 ° C. extensional viscosity measurement (strain hardening “none”) The strain hardening degree (λmax) cannot be calculated, and the ratio (N1 / SS) of the first normal stress difference (N1) to the shear stress (SS) in the transient response measurement at 180 ° C. strain rate of 10 / sec is In addition, linear propylene.composition Q.5.6 of the whole component A-1f and ethylene content of the linear ethylene / propylene random copolymer portion of 39% by weight (measured by a cross fractionation method). Ethylene block copolymer (antioxidant / neutralizing agent, added pellets).

Production Example 7 (Component A-1g):
A stainless steel autoclave with a stirrer having an internal volume of 400 liters was sufficiently replaced with propylene gas, and 120 liters of dehydrated and deoxygenated n-heptane was added as a polymerization solvent. Next, 30 g of triethylaluminum, 70 liters of hydrogen, and 15 g of a solid catalyst component (b) containing polypropylene were added under a temperature of 70 ° C. After the autoclave was heated to an internal temperature of 75 ° C., propylene was supplied at a rate of 17.0 kg / hour and hydrogen was supplied at a rate of 34.0 L / hour to initiate polymerization. After 230 minutes, the introduction of propylene and hydrogen was stopped. The pressure of the polymerization initiator at 0.32 kg / ^cm 2 G, increased over time in propylene feed was increased to 3.4 kg / cm ² G at a feed stop time. Then, after the pressure in the vessel is subjected to residual polymerization until drops to 2.5 kg / cm ² G, and releasing the unreacted gas to 0.3 kg / cm ^2. During this time, the polymerization temperature was maintained in the range of 75 ± 1 ° C. (one-stage polymerization).
Next, after setting the autoclave at an internal temperature of 65 ° C., 16.0 cc of n-butanol was introduced, and then propylene was supplied at a rate of 2.7 kg / hour and ethylene was supplied at a rate of 7.0 kg / hour to start two-stage polymerization. did. After 60 minutes, the introduction of propylene and ethylene was stopped. The pressure increased with time during the supply of propylene and ethylene, and increased to 1.0 kg / cm ² G when the supply was stopped. Thereafter, the unreacted gas in the vessel was released to 0.3 kg / cm ² . During this time, the polymerization temperature was maintained in the range of 65 ± 1 ° C. (two-stage polymerization).
The obtained slurry was transferred to the next tank with a stirrer, 5 liters of butanol was added, treated at 70 ° C. for 3 hours, further transferred to the next tank with a stirrer, and 100 liters of pure water in which 100 g of sodium hydroxide was dissolved. In addition, after treating for 1 hour, the aqueous layer was allowed to stand and then separated to remove the catalyst residue. The slurry was treated with a centrifugal separator to remove heptane, and then treated with a dryer at 80 ° C. for 3 hours to completely remove heptane to obtain a propylene / ethylene block copolymer (A-1 g).
The resulting propylene / ethylene block copolymer was adjusted for melt viscosity with a peroxide.

The linear propylene / ethylene block copolymer (A-1g) has an MFR (230 ° C., 2.16 kg load) of the linear propylene polymer portion of 70 g / 10 min, linear ethylene / propylene random copolymer ratio is 14.1% by weight with respect to the entire component a-1 g of the united portion, the intrinsic viscosity _{[eta] copoly} of linear ethylene-propylene random copolymer portion is 7.8dl / g, component a-1 g total MFR ( 230 ° C., 2.16 kg load) is 60 g / 10 min, the die swell ratio of the whole component A-1g is 1.1, and shows strain hardening in 180 ° C. extensional viscosity measurement (strain hardening “Yes”). The strain hardening degree (λmax) is 2.00, and the ratio (N1 / SS) of the first normal stress difference (N1) to the shear stress (SS) in the transient response measurement at a 180 ° C. strain rate of 10 / sec. 1 26, and further, the linear propylene / ethylene having a Q value of the whole component A-1g of 7.3 and an ethylene content of the linear ethylene / propylene random copolymer portion of 65% by weight (measured by a cross fractionation method) Block copolymer (antioxidant / neutralizing agent, added pellet).

(2) Component B:
(B-1): Chemical foaming agent master batch (Polyslen EE25C manufactured by Eiwa Chemical Co., Ltd., foaming agent concentration 20%, amount of generated gas 75 to 90 ml / 2.5 g (220 ° C. under constant temperature × 20 min)). Acid-based, low-density polyethylene base.
(B-2): Carbon dioxide gas.
(B-3): Nitrogen gas.

(3) Component C:
(C-1): Talc (Fuji Talc Kogyo Co., Ltd., average particle size 5.1 μm, average aspect ratio 6).

[Examples 1 to 8]
Each component A, component B, and component C were blended and blended in the proportions shown in Tables 1 and 3, and performance evaluation was performed on those molded under the following conditions. The evaluation results are shown in Table 2 and Table 4.

1. Conditions for Examples 1-4 and Example 8:
(1) Injection molding machine: “α-300” manufactured by FANUC.
(2) Mold: 400 mm long × 200 mm wide, having a plate-shaped cavity with variable thickness by adjusting the position of the movable mold, and having an initial cavity clearance (T ₀ ) of 1.3 mm.
(3) Molding conditions: cylinder temperature 210 ° C., mold temperature 40 ° C., injection speed 25-220 mm / sec, cooling time 30 sec.
(4) Molding method: mold opening injection foaming in which the initial cavity clearance (T ₀ ) is 1.3 mm and the cavity clearance after core back (T ₁ ) is 2.5 mm, 3.5 mm and 4.0 mm Molding.

2. Conditions for Examples 5-7:
(1) Injection molding machine: “J35-AD” manufactured by Nippon Steel Works.
(2) Mold: A plate-shaped cavity having a thickness of 80 mm × 50 mm and a variable thickness by adjusting the position of the movable mold, and an initial cavity clearance (T ₀ ) of 1.3 mm.
(3) Molding conditions: cylinder temperature 210 ° C., mold temperature 40 ° C., injection speed 100 mm / second, cooling time 30 seconds, gas injection pressure 25 MPa (supercritical state).
(4) Molding method: injection foam molding similar to those in Examples 1 to 5 described above.

[Comparative Examples 1-4]
Each component A and component B were blended and blended in the proportions shown in Table 1, and performance evaluation was performed on those molded under the same conditions as in Examples 1 to 4. The evaluation results are shown in Table 2.

  From the results shown in Tables 1 to 4, the linear polypropylene resin compositions and injection-foamed molded articles having the compositions shown in Examples 1 to 8 that satisfy the respective requirements in the essential constituent elements of the present invention are all good. The linear polypropylene resin composition and injection foam molded article having the surface appearance and injection foam moldability, and in particular having the composition shown in Example 8 in which the component C filler is blended, have good surface appearance. It has injection foam moldability and high rigidity. The rigidity of Example 2, that is, the load value at a strain of 10 mm, was 21.6 N when the set foaming ratio was 1.9 times, and 38.2 N when the set foaming ratio was 2.7 times. All of these can be significantly reduced in weight, are excellent in recyclability and environmental adaptability, and are automotive parts, industrial parts including television parts and other home appliances, parts of electronic products, building material parts, preferably automobile parts. In particular, it has become clear that it has performance suitable for automobile interior parts such as trims, ceiling materials, trunks, instrument panels, pillars and the like.

On the other hand, the linear polypropylene resin compositions and injection-foamed molded articles having the compositions shown in Comparative Examples 1 to 4 are inferior due to their poor performance balance.
For example, (1) Comparative Example 1 was significantly different from Examples 2 to 4 in surface appearance and injection foam moldability because the MFR of the entire component A was low. In Comparative Example 2, the strain hardenability was exhibited, and although the surface appearance was equivalent to that of Examples 2 to 4, the MFR of the entire component A was low, so that the injection foam moldability was remarkable as in Examples 2 to 4. Differences have occurred. This indicates that it is essential that the MFR of component A as a whole meets the requirements of the present invention.
(2) Although the comparative example 4 showed strain hardening property, since the MFR of the linear propylene polymer portion was low, the injection foam moldability was significantly different from those of Examples 2 to 4. This indicates that it is essential that the MFR of the linear propylene polymer portion satisfies the requirements of the present invention.
(3) In Comparative Example 3, although the MFR of the linear propylene polymer portion and the MFR of Component A as a whole satisfy the requirements of this project, they do not exhibit strain hardening, and shear stress (SS) Since the ratio (N1 / SS) of the first normal stress difference (N1) with respect to was small, a significant difference was produced from Examples 2 to 4 in the injection foaming moldability. This indicates that it is essential that the ratio (N1 / SS) of the first normal stress difference (N1) to the strain hardening and shear stress (SS) satisfies the requirements of the present invention.
From the results of the above examples and comparative examples, the rationality and significance of the configuration and requirements of the present invention are demonstrated, and the superiority of the present invention over the prior art is also apparent.

  The linear polypropylene resin composition and injection-foamed molded article of the present invention have good surface appearance, injection-foaming moldability, rigidity and other physical properties, and can be significantly reduced in weight. Due to its excellent environmental adaptability, industrial parts such as automobile parts, television household appliances, electronic parts, etc., building material parts, preferably automobile parts, especially trims, ceiling materials, trunks, instrument panels, pillars It can be suitably used for automobile interior parts and the like.

Claims (9)

A linear propylene / ethylene block copolymer (component A-1) comprising the linear propylene polymer portion and the linear ethylene / propylene random copolymer portion and having the following characteristics (i) to (vi): A polypropylene resin (component A) comprising 30 to 100% by weight, another propylene polymer (component A-2) 0 to 70% by weight, and a foaming agent (component B). A chain polypropylene resin composition.
Characteristic (i): The melt flow rate (230 ° C., 2.16 kg load) of the linear propylene polymer portion is 130 g / 10 min or more.
Characteristic (ii): The ratio of the linear ethylene / propylene random copolymer portion to the entire linear propylene / ethylene block copolymer (component A-1) is 2 to 50% by weight.
Characteristic (iii): Melt flow rate (230 ° C., 2.16 kg load) exceeds 60 g / 10 min.
Characteristic (iv): Die swell ratio is 1.2 to 2.5.
Characteristic (v): Shows strain hardening in 180 ° C. extensional viscosity measurement.
Characteristic (vi): The ratio (N1 / SS) between the first normal stress difference (N1) and the shear stress (SS) in the melt viscoelasticity measurement is 1.01 or more. The linear propylene-ethylene block copolymer (Component A-1), the intrinsic viscosity of the linear ethylene-propylene random copolymer portion _{[eta] copoly} is 5.3~15.0dl / g The linear polypropylene resin composition according to claim 1, wherein   The linear propylene / ethylene block copolymer (component A-1) has a weight average molecular weight (Mw) to number average molecular weight (Mn) ratio (Q value: Mw / Mn) of 7 to 13. The linear polypropylene resin composition according to claim 1 or 2, characterized in that   The ethylene content of the linear ethylene / propylene random copolymer portion in the linear propylene / ethylene block copolymer (component A-1) is 15 to 15% with respect to the total amount of the linear ethylene / propylene random copolymer. It is 80 weight%, The linear polypropylene resin composition in any one of Claims 1-3 characterized by the above-mentioned.   The linear polypropylene resin composition according to any one of claims 1 to 4, comprising 1 to 70 parts by weight of filler (component C) with respect to 100 parts by weight of polypropylene resin (component A). object.   6. The linear polypropylene resin composition according to claim 5, wherein the filler (component C) is at least one selected from talc, polyester fiber, whisker, glass fiber, or carbon fiber.   The linear polypropylene resin composition according to any one of claims 1 to 6, comprising 1 to 50 parts by weight of an elastomer (component D) with respect to 100 parts by weight of the polypropylene resin (component A). object.   An injection foam molded article comprising the linear polypropylene resin composition according to any one of claims 1 to 7. The mold is composed of a fixed mold and a movable mold capable of moving forward and backward, and has a mold cavity clearance (T ₀ ) smaller than the mold cavity clearance (T ₁ ) corresponding to the shape position of the final product. An injection process of injecting and filling a molten or semi-molten linear polypropylene resin composition into the mold cavity, and retracting the movable mold to the mold cavity clearance (T ₁ ) A mold-opening injection molding method comprising a foaming step for filling a void in a mold cavity, and a method for producing an injection foam molded product comprising a linear polypropylene resin composition, wherein the linear polypropylene resin composition In the injection process for injection filling, the injection rate for a pre-foamed molded body filling volume of 100% is molded under the condition of 20% / second or more. Method for producing an injection molded foam product of claim 8.