JP2004027124A - Polyolefin resin composition for use in foaming, foamed molding and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyolefin resin composition for use in foaming having excellent foaming properties, flexibility and mechanical strength such as tear strength and capable of obtaining a foamed molding with less dust generation caused by bleed of a low molecular weight component and an additive. <P>SOLUTION: This polyolefin resin composition for use in foaming comprises a resin component containing 100-5 mass% of an ethylene (co)polymer (A) and 0-95 mass% of another polyolefin resin (B), and 0.5-20 pts.mass of a foaming agent (C) per 100 pts.mass of the resin component. The ethylene (co)polymer has a density of 0.86-0.97 g/cm<SP>3</SP>, a melt flow rate of 0.1-100 g/10min, a molecular weight distribution (Mw/Mn) of 1.5-4.5 and satisfies a relationship of T<SB>75</SB>-T<SB>25</SB>≤-670×d+644, wherein T<SB>25</SB>represents a temperature at which 25% of a total eluate calculated from an integrated elution curve of elution temperature-elution amount by a continuous temperature rise eluting fractionation method and T<SB>75</SB>represents a temperature at which 75% of the total eluate, and d represents a density. <P>COPYRIGHT: (C)2004,JPO

Description

【００９２】
［他のポリオレフィン系樹脂（Ｂ）］
市販の高密度ポリエチレン（ＨＤＰＥ）
密度：０．９５１ｇ／ｃｍ^３　、ＭＦＲ：０．３ｇ／１０分（商品名：ジェイレックス−ＨＤ　ＫＶ１７５Ｎ、日本ポリオレフィン（株）製）
【００９３】
［実施例１］
エチレン共重合体（Ａ１１）１００質量部に、発泡剤として炭酸水素ナトリウム１．０質量部、無水クエン酸モノソーダ−１．０質量部と発泡助剤としてタルク（発泡核剤）０．０３質量部を加え、二軸押出機（口径６５ｍｍ）で溶融混練し、この押出機に連結しているコートハンガータイプのＴダイから１４０℃の温度で押出し、約２ｍｍ厚の発泡シートを得た。得られた発泡シートの見かけ密度、引張強度等を測定した結果を表２に示した。
試験法は以下のとおりである。
【００９４】
［見かけ密度］
電子比重計（ミラージュ社製ＭＤ−２００Ｓ型）により測定した。
［気泡の均一性］
発泡シートの断面を肉眼で目視し、気泡が均一になっているものを○、若干気泡が不均一なものが混在しているものを△、気泡が不均一なものを×とした。
【００９５】
［引張試験］
ＡＳＴＭ　Ｄ６３８に準拠して、５０ｍｍ／分の条件で発泡シートの引張試験を行い、破断点抗張力および破断点伸びを測定した。
［引裂試験］
ＪＩＳ　Ｋ６７６７に準拠し、クレーブ法引裂試験を用いて速度５００ｍｍ／分の条件で引裂強度を測定した。
【００９６】
［実施例２〜６］
（Ａ）成分のエチレン共重合体（Ａ１１）に（Ｂ）成分の高密度ポリエチレンを表２に示す配合で混合した以外は、実施例１と同様にして発泡シートを得て、評価した結果を表２に示した。
【００９７】
［実施例７〜９］
（Ａ）成分のエチレン共重合体（Ａ１１）を、エチレン共重合体（Ａ１２）、エチレン共重合体（Ａ２）、エチレン共重合体（Ａ３）に代えた以外は、実施例６に準拠して発泡シートを得て、評価した結果を表２に示した。
【００９８】
【表２】

【００９９】
［比較例１〜６］
（Ａ）成分のエチレン共重合体（Ａ１１）を他のエチレン共重合体（Ａ４）に代え、（Ｂ）成分の高密度ポリエチレンを表２に示す配合で混合した以外は、実施例１に準拠して発泡シートを得て、評価した結果を表３に示した。
【０１００】
【表３】

【０１０１】
【発明の効果】
以上説明したように、本発明の発泡用ポリオレフィン系樹脂組成物は、上述の（ａ）〜（ｄ）の要件を満足するエチレン（共）重合体（Ａ）１００〜５質量％および他のポリオレフィン系樹脂（Ｂ）０〜９５質量％を含む樹脂成分と、該樹脂成分１００質量部に対して０．５〜２０質量部の発泡剤（Ｃ）を含有するものであるので、従来のポリエチレン系樹脂発泡体よりも発泡特性、柔軟性、引裂強度等の機械的強度等に優れ、低分子量成分やステアリン酸カルシウム、ステアリン酸亜鉛のような塩素キャッチャー等の添加物のブリードによる塵発生が少なく、とりわけ医療、エレクトロニクス、食品包装等の分野に適した発泡成形体を提供することができる。
【図面の簡単な説明】
【図１】本発明に係るエチレン（共）重合体（Ａ）の溶出温度−溶出量曲線を示すグラフである。
【図２】本発明に係るエチレン（共）重合体（Ａ１）の溶出温度−溶出量曲線を示すグラフである。
【図３】一般のメタロセン系触媒によるエチレン（共）重合体の溶出温度−溶出量曲線を示すグラフである。
【図４】本発明に係るエチレン（共）重合体（Ａ２）の溶出温度−溶出量曲線を示すグラフである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a polyolefin-based resin composition for foaming and a foamed molded product thereof, and more specifically, a polyolefin-based resin composition capable of providing a foamed molded product excellent in foaming properties, flexibility, mechanical strength such as tear strength, and the like. The present invention relates to a foam molded article and a production method thereof.
[0002]
[Prior art]
BACKGROUND ART Foams made of polyolefin resins such as polyethylene and polypropylene have excellent flexibility and heat insulating properties, and have been conventionally used for various uses as cushioning materials or heat insulating materials. The type of such a polyethylene resin is selected according to the purpose of use. For example, when the foam requires flexibility, a linear low-density polyethylene is used, and toughness is required. In such a case, a linear low-density polyethylene or a resin composition comprising a high-pressure low-density polyethylene and a linear low-density polyethylene (JP-B-61-57334) is used.
[0003]
The linear low-density polyethylene is composed of an ethylene-α-olefin copolymer, and in order to increase the flexibility of the foam, it is supported by lowering the density of the linear low-density polyethylene. . However, when the density is reduced in this manner, the linear low-density polyethylene is composed of a low-molecular-weight component in which a large amount of a comonomer is introduced and a high-molecular-weight component in which a comonomer is hardly introduced, so that the melt viscosity is low. However, there is a problem that the foaming ratio does not increase due to a large variation in the expansion ratio. Even if a foam having a satisfactory expansion ratio can be obtained, there are problems such as appearance irregularities, and very large or small bubbles are mixed and broken from the non-uniformly foamed portion during secondary processing. Was.
[0004]
Further, when the foam is applied to a floor material or an interior material, a surface dent is generated due to abrasion, which often causes a problem in appearance. Therefore, the appearance of a foam having better foaming properties, mechanical properties, and appearance than conventional polyethylene resin foams is desired.
[0005]
[Problems to be solved by the invention]
Therefore, an object of the present invention is to provide a foaming property, flexibility, mechanical strength such as tear strength, etc., higher than conventional polyethylene-based resin foams, low molecular weight components and chlorine catchers such as calcium stearate and zinc stearate. The present invention provides a polyolefin resin composition for foaming, a foamed molded article, and a method for producing the same, which can provide a foamed molded article which is less likely to generate dust due to bleeding of an additive and is particularly suitable for medical, electronics, food packaging and other fields. Is to do.
[0006]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to improve the drawbacks of the conventional polyolefin resin composition for foaming, and as a result, have completed the present invention.
That is, the polyolefin resin composition for foaming of the present invention comprises 100 to 5% by mass of an ethylene (co) polymer (A) satisfying the following requirements (a) to (d) and another polyolefin resin (B). It is characterized by containing a resin component containing 0 to 95% by mass and 0.5 to 20 parts by mass of a foaming agent (C) based on 100 parts by mass of the resin component.
(A) 0.86-0.97 g / cm density³,
(B) a melt flow rate of 0.1 to 100 g / 10 minutes,
(C) a molecular weight distribution (Mw / Mn) of 1.5 to 4.5,
(D) The temperature T at which 25% of the whole is eluted, determined from the integrated elution curve of the elution temperature-elution amount curve by the continuous heating elution fractionation method (TREF).₂₅And the temperature T at which 75% of the whole elutes₇₅And the difference T₇₅-T₂₅And the density d satisfies the relationship of the following (formula 1).
(Equation 1) ΔT₇₅-T₂₅≦ −670 × d + 644
[0007]
Further, it is desirable that the ethylene (co) polymer (A) further satisfies the following requirement (e).
(E) The temperature T at which 25% of the whole is eluted, obtained from the integrated dissolution curve of the elution temperature-elution amount curve by the continuous heating elution fractionation method (TREF).₂₅And the temperature T at which 75% of the whole elutes₇₅And the difference T₇₅-T₂₅And the density d satisfies the following relationship (Equation 2):
(Equation 2) d <0.950 g / cm³ When
T₇₅-T₂₅≧ −300 × d + 285
d ≧ 0.950 g / cm³ When
T₇₅-T₂₅≧ 0
[0008]
The ethylene (co) polymer (A) satisfies the following requirements (f) and (g), or satisfies the following requirements (h) and (i). It is preferable that the ethylene (co) polymer (A2) be used.
(F) Orthodichlorobenzene (ODCB) soluble content X (mass%), density d and melt flow rate (MFR) at 25 ° C. satisfy the following formulas (3) and (4).
(Equation 3) When d−0.008 log MFR ≧ 0.93
X <2.0
(Equation 4) When d−0.008 log MFR <0.93
X <9.8 × 10³X (0.9300-d + 0.008 log MFR)²+2.0
(G) The presence of a plurality of peaks in the elution temperature-elution amount curve by the continuous temperature elution fractionation method (TREF)
(H) One peak of the elution temperature-elution amount curve by the continuous heating elution fractionation method (TREF)
(I) One or more melting point peaks, and the highest melting point Tml and density d among them satisfy the relationship of the following (Equation 5).
(Equation 5) ΔTml ≧ 150 × d−19
[0009]
Further, it is desirable that the ethylene (co) polymer (A2) further satisfies the following requirement (j).
(J) Melt tension (MT) and melt flow rate (MFR) satisfy the following (Equation 6).
(Formula 6) ΔlogMT ≦ −0.572 × logMFR + 0.3
Further, the halogen concentration in the ethylene (co) polymer (A) is desirably 10 ppm or less.
[0010]
Further, the ethylene (co) polymer (A) is desirably produced by a catalyst containing at least an organic cyclic compound having a conjugated double bond and a transition metal compound of Group IV of the periodic table.
Further, the resin component desirably comprises 5% by mass or more of ethylene (co) polymer (A) and 95% by mass or less of high-density polyethylene.
The foaming agent (C) is preferably a pyrolytic foaming agent or a gas foaming agent.
[0011]
Further, the foamed molded article of the present invention comprises the polyolefin-based resin composition for foaming of the present invention, and is characterized by having an expansion ratio of 1.2 to 30 times.
Further, the foamed molded article of the present invention is desirably a crosslinked foam.
Further, the method for producing a foamed molded article of the present invention comprises molding a polyolefin resin composition for foaming containing the resin component and a pyrolytic foaming agent, and decomposing the pyrolytic foaming agent by heat to obtain an expansion ratio. Is obtained by obtaining 1.2 to 30 times the foam molded article.
Further, the method for producing a foamed molded article of the present invention is characterized in that when molding the resin component, a gas-type foaming agent is injected to obtain a foamed molded article having an expansion ratio of 1.2 to 30 times. .
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
[Ethylene (co) polymer (A)]
The ethylene (co) polymer (A) in the present invention is an ethylene homopolymer or an ethylene obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms, preferably 3 to 12 carbon atoms. -Α-olefin copolymer.
Examples of the α-olefin include propylene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, and the like. It is desirable that the content of these α-olefins is generally selected in a range of usually 30 mol% or less, preferably 3 to 20 mol% or less.
[0013]
The (a) density of the ethylene (co) polymer (A) in the present invention is 0.86 to 0.97 g / cm.³, Preferably 0.88 to 0.95 g / cm³, More preferably 0.90 to 0.94 g / cm³範 囲 range. 0.86g / cm density³If it is less than, rigidity and heat resistance are inferior. The density is 0.97 g / cm³If the value exceeds, there is a possibility that the material is too hard and the mechanical strength such as tear strength and impact strength becomes insufficient.
[0014]
The melt flow rate (hereinafter, referred to as MFR) of the ethylene (co) polymer (A) is 0.01 to 100 g / 10 min, preferably 0.1 to 50 g / 10 min, more preferably 0.1 to 50 g / 10 min. It is in the range of 1 to 30 g / min. If the MFR is less than 0.01 g / 10 minutes, the moldability will be poor, and if it exceeds 100 g / 10 minutes, the mechanical strength and the like may be poor.
[0015]
The (c) molecular weight distribution (Mw / Mn) of the ethylene (co) polymer (A) is in the range of 1.5 to 4.5, preferably 2.0 to 4.0, and more preferably 2.5 to 3 0.0. If Mw / Mn is less than 1.5, molding processability will be poor, and if Mw / Mn exceeds 4.5, the foaming performance and the like may be poor.
[0016]
Here, the molecular weight distribution (Mw / Mn) of the ethylene (co) polymer (A) was determined by gel permeation chromatography (GPC) to determine the mass average molecular weight (Mw) and the number average molecular weight (Mn). It can be determined by calculating the ratio (Mw / Mn).
[0017]
As shown in FIG. 1, for example, as shown in FIG. 1, 25% of the ethylene (co) polymer (A) was (d) 25% of the total obtained from an integrated elution curve of an elution temperature-elution amount curve by a continuous heating elution fractionation method (TREF). Elution temperature T₂₅And the temperature T at which 75% of the whole elutes₇₅And the difference T₇₅-T₂₅And the density d must satisfy the following relationship (Equation 1).
(Equation 1) ΔT₇₅-T₂₅≦ −670 × d + 644
T₇₅-T₂₅And the density d do not satisfy the relationship of the above (formula 1), uniform foam cells cannot be obtained at the time of foaming.
[0018]
The method of measuring TREF is as follows. First, a sample is added to ODCB to which an antioxidant (for example, butylhydroxytoluene) is added so that the sample concentration becomes 0.05% by mass, and heated and dissolved at 140 ° C. 5 ml of this sample solution is injected into a column filled with glass beads, cooled to 25 ° C. at a cooling rate of 0.1 ° C./min, and the sample is deposited on the surface of the glass beads. Next, the sample is sequentially eluted while raising the column temperature at a constant rate of 50 ° C./hr while flowing ODCB through the column at a constant flow rate. At this time, the concentration of the sample eluted in the solvent was 2925 cm, the wave number of the asymmetric stretching vibration of methylene.^-1Is continuously detected by measuring the absorption with respect to an infrared detector. From this value, the concentration of the ethylene (co) polymer in the solution is quantitatively analyzed to determine the relationship between the elution temperature and the elution rate. According to the TREF analysis, the change in the elution rate with respect to the temperature change can be continuously analyzed with a very small amount of sample, so that relatively fine peaks that cannot be detected by the fractionation method can be detected.
[0019]
The ethylene (co) polymer (A) further has a temperature T at which 25% of the total eluted from (e) an integrated elution curve of an elution temperature-elution amount curve obtained by continuous temperature elution fractionation (TREF).₂₅And the temperature T at which 75% of the whole elutes₇₅And the difference T₇₅-T₂₅It is desirable that the density d satisfies the following relationship (Equation 2).
(Equation 2) d <0.950 g / cm³ When
T₇₅-T₂₅≧ −300 × d + 285
d ≧ 0.950 g / cm³ When
T₇₅-T₂₅≧ 0
T₇₅-T₂₅When the density d satisfies the above (Equation 2), the foam cells become uniform and the performance such as heat resistance is improved.
[0020]
The ethylene (co) polymer (A) is an ethylene (co) polymer (A1) satisfying the requirements of (f) and (g) described below, or the requirements of (h) and (i) described further below. It is preferable that the ethylene (co) polymer of the ethylene (co) polymer (A2) satisfying the following conditions.
[0021]
(F) The amount X (mass%) of the ODCB-soluble component at 25 ° C., the density d and the MFR of the ethylene (co) polymer (A1) satisfy the relationships of the following (formula 3) and (formula 4). Yes,
(Equation 3) When d−0.008 log MFR ≧ 0.93,
X <2.0
(Equation 4) When d−0.008 log MFR <0.93,
X <9.8 × 10³X (0.9300-d + 0.008 log MFR)²+2.0
Is satisfied, preferably,
d-0.008 log When MFR ≧ 0.93,
X <1.0
When d−0.008 log MFR <0.93,
X <7.4 × 10³X (0.9300-d + 0.008 log MFR)²+2.0
Is satisfied, and more preferably,
d-0.008 log When MFR ≧ 0.93,
X <0.5
When d−0.008 log MFR <0.93,
X <5.6 × 10³X (0.9300-d + 0.008 log MFR)²+2.0
Satisfied with the relationship.
[0022]
Here, the amount X of the ODCB-soluble component at 25 ° C. is measured by the following method. 0.5 g of the sample is heated at 135 ° C. for 2 hours in 20 ml of ODCB to completely dissolve the sample and then cooled to 25 ° C. After leaving this solution at 25 ° C. overnight, the solution is filtered through a Teflon (registered trademark) filter to collect a filtrate. This filtrate, which is a sample solution, was subjected to infrared spectroscopy to measure the asymmetric stretching vibration of methylene with a wave number of 2925 cm.^-1The intensity of the nearby absorption peak is measured, and the sample concentration is calculated from a calibration curve created in advance. From this value, the ODCB-soluble content at 25 ° C. is determined.
[0023]
The ODCB-soluble component at 25 ° C. is a high branching degree component and a low molecular weight component contained in the ethylene (co) polymer, and causes a decrease in heat resistance and a sticky surface of a molded product, which causes a problem of hygiene and a problem in the molded product. It is desirable that this content be low because it causes blocking of the surface. The amount of the ODCB-soluble component is affected by the α-olefin content and the molecular weight of the entire copolymer, that is, the density and the MFR. Therefore, the fact that the density and the amounts of MFR and ODCB-soluble component, which are these indices, satisfy the above relationship indicates that the uneven distribution of α-olefin contained in the whole copolymer is small.
[0024]
In addition, the ethylene (co) polymer (A1) has a plurality of peaks in the elution temperature-elution amount curve obtained by (g) continuous heating elution fractionation (TREF). It is particularly preferable that the peak temperature on the high temperature side of the plurality of peaks exists between 85 ° C and 100 ° C. The presence of this peak increases the melting point, increases the crystallinity, and improves the heat resistance and rigidity of the molded body.
[0025]
In addition, as shown in FIG. 4, the ethylene (co) polymer (A2) has one peak of an elution temperature-elution amount curve obtained by (h) continuous heating elution fractionation (TREF).
Further, the ethylene (co) polymer (A2) has (i) one or more melting point peaks, and the highest melting point Tml and the density d satisfy the relationship of the following (Equation 5).
(Equation 5) ΔTml ≧ 150 × d−19
When the melting point Tm1 and the density d satisfy the above relationship (Equation 5), the heat resistance is improved.
[0026]
Further, among the ethylene (co) polymers (A2), an ethylene (co) polymer that further satisfies the requirement of (j) below is preferable.
(J) Melt tension (MT) and melt flow rate (MFR) satisfy the relationship of the following (Equation 6).
(Formula 6) ΔlogMT ≦ −0.572 × logMFR + 0.3
When the MT and the MFR satisfy the relationship of the above (formula 6), the moldability such as extrusion molding is improved.
[0027]
Here, as shown in FIG. 2, the ethylene (co) polymer (A1) substantially has a plurality of special peaks in the elution temperature-elution amount curve obtained by the continuous heating elution fractionation method (TREF). Ethylene-α-olefin copolymer.
On the other hand, the ethylene (co) polymer shown in FIG. 3 is an ethylene (co) polymer having substantially one peak in an elution temperature-elution amount curve determined by a continuous heating elution fractionation method (TREF). This corresponds to a typical metallocene-based ethylene (co) polymer.
As shown in FIG. 4, the ethylene (co) polymer (A2) has one TREF peak as shown in FIG. Not satisfied). Therefore, the ethylene (co) polymer (A2) is clearly distinguished from the conventional typical metallocene-based catalyst-based ethylene (co) polymer (FIG. 3).
[0028]
The ethylene (co) polymer (A) in the present invention may be produced with a general metallocene-based catalyst, CGC catalyst, or the like, but is preferably an organic cyclic compound having at least a conjugated double bond and a compound of the periodic table. A linear low-density ethylene (co) polymer obtained by homopolymerizing ethylene or copolymerizing ethylene and an α-olefin in the presence of a catalyst containing a Group IV transition metal compound. Such a linear low-density ethylene (co) polymer has a narrow molecular weight distribution and a narrow composition distribution, and thus has excellent mechanical properties, excellent uniformity of foam cells, and excellent heat resistance.
[0029]
In the production of the ethylene (co) polymer (A) in the present invention, ethylene is homopolymerized in the presence of a catalyst containing at least an organic cyclic compound having a conjugated double bond and a transition metal compound of Group IV of the periodic table, or It is preferably a linear ethylene (co) polymer obtained by copolymerizing ethylene and an α-olefin. In particular, it is desirable to carry out polymerization with a catalyst obtained by mixing the following compounds a1 to a4.
a1: General formula Me¹R¹ _pR² _q(OR³)_rX¹ _4-pqr化合物 (in the formula, Me¹Represents zirconium, titanium, hafnium, and R¹And R³Represents a hydrocarbon group having 1 to 24 carbon atoms,²Represents a 2,4-pentanedionato ligand or a derivative thereof, a benzoylmethanato ligand, a benzoylacetonato ligand or a derivative thereof, X¹Represents a halogen atom, and p, q and r are integers satisfying the ranges of 0 ≦ p ≦ 4, 0 ≦ q ≦ 4, 0 ≦ r ≦ 4, and 0 ≦ p + q + r ≦ 4, respectively.
a2: General formula Me²R⁴ _m(OR⁵)_nX² _zmn化合物 (in the formula, Me²Is an element of Groups I to III of the periodic table, R⁴And R⁵Represents a hydrocarbon group having 1 to 24 carbon atoms, X²Represents a halogen atom or a hydrogen atom (however, X²Me when is a hydrogen atom²Represents a Group III element of the periodic table), and z represents Me²And m and n are integers satisfying the ranges of 0 ≦ m ≦ z and 0 ≦ n ≦ z, respectively, and 0 ≦ m + n ≦ z.
a3: Organic cyclic compound having a conjugated double bond
a4: Modified organic aluminum oxy compound and / or boron compound containing Al—O—Al bond
[0030]
The details are described below.
The general formula Me of the catalyst component a1¹R¹ _pR² _q(OR³)_rX¹ _4-pqrIn the formula of the compound represented by, Me¹Represents zirconium, titanium, and hafnium, and the type of these transition metals is not limited, and a plurality of transition metals can be used, but it is particularly preferable that zirconium, which has excellent weather resistance of the copolymer, is contained. R¹And R³Is a hydrocarbon group having 1 to 24 carbon atoms, preferably 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms. Specifically, alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group and butyl group; alkenyl groups such as vinyl group and allyl group; phenyl group, tolyl group, xylyl group, mesityl group, indenyl group and naphthyl group And an aralkyl group such as a benzyl group, a trityl group, a phenethyl group, a styryl group, a benzhydryl group, a phenylbutyl group, and a neofuyl group.
These may have branches. R²Indicates a 2,4-pentanedionato ligand or a derivative thereof, a benzoylmethanato ligand, a benzoylacetonato ligand or a derivative thereof. X¹Represents a halogen atom such as fluorine, iodine, chlorine and bromine. p and q are integers satisfying the ranges of 0 ≦ p ≦ 4, 0 ≦ q ≦ 4, 0 ≦ r ≦ 4, and 0 ≦ p + q + r ≦ 4, respectively.
[0031]
Examples of the compound represented by the general formula of the catalyst component a1 include tetramethyl zirconium, tetraethyl zirconium, tetrabenzyl zirconium, tetrapropoxy zirconium, tripropoxy monochlorodiconium, tetraethoxy zirconium, tetrabutoxy zirconium, tetrabutoxy titanium, tetrabutoxy titanium And Zr (OR) such as tetrapropoxyzirconium and tetrabutoxyzirconium.₄Compounds are preferred, and they may be used in combination of two or more. Specific examples of the 2,4-pentanedionato ligand or derivative thereof, benzoylmethanato ligand, benzoylacetonato ligand or derivative thereof include tetra (2,4-pentanedionato) zirconium. , Tri (2,4-pentanedionato) chloride zirconium, di (2,4-pentanedionato) dichloride zirconium, (2,4-pentanedionato) trichloride zirconium, di (2,4-pentanedionato) Diethoxide zirconium, di (2,4-pentanedionato) di-n-propoxide zirconium, di (2,4-pentanedionato) di-n-butoxide zirconium, di (2,4-pentane Dionato) dibenzyl zirconium, di (2,4-pentanedionato) dineofylzirconium, tetra ( Benzoylmethanato) zirconium, di (dibenzoylmethanato) dioxide zirconium, di (dibenzoylmethanato) di-n-propoxide zirconium, di (dibenzoylmethanato) di-n-butoxide zirconium, di (benzoyl) (Acetonato) dioxide zirconium, di (benzoylacetonato) di-n-propoxide zirconium, di (benzoylacetonato) di-n-butoxide zirconium and the like.
[0032]
The general formula Me of the catalyst component a2²R⁴ _m(OR⁵)_nX² _zmnMe in the formula of the compound represented by²Represents an element of Groups I to III of the periodic table, such as lithium, sodium, potassium, magnesium, calcium, zinc, boron, and aluminum. R⁴And R⁵Is a hydrocarbon group having 1 to 24 carbon atoms, preferably 1 to 12 carbon atoms, and more preferably 1 to 8 carbon atoms. Specific examples thereof include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, and butyl group. Alkenyl groups such as vinyl group and allyl group; aryl groups such as phenyl group, tolyl group, xylyl group, mesityl group, indenyl group and naphthyl group; benzyl group, trityl group, phenethyl group, styryl group, benzhydryl group and phenyl An aralkyl group such as a butyl group and a neofuyl group is exemplified. These may have branches. X²Represents a halogen atom or a hydrogen atom such as fluorine, iodine, chlorine and bromine. Where X²Me when is a hydrogen atom²Is limited to the case of Group III III elements of the periodic table exemplified by boron, aluminum and the like. Z is Me²And m and n are integers satisfying the ranges of 0 ≦ m ≦ z and 0 ≦ n ≦ z, respectively, and 0 ≦ m + n ≦ z.
[0033]
Examples of the compound represented by the general formula of the catalyst component a2 include organic lithium compounds such as methyl lithium and ethyl lithium; organic magnesium compounds such as dimethyl magnesium, diethyl magnesium, methyl magnesium chloride, and ethyl magnesium chloride; dimethyl zinc, diethyl Organic zinc compounds such as zinc; organic boron compounds such as trimethylboron and triethylboron; trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, trihexylaluminum, tridecylaluminum, diethylaluminum chloride, ethylaluminum dichloride, ethylaluminum Sesquichloride, diethyl aluminum ethoxide, diethyl aluminum hydride Any derivative of an organic aluminum compound, and the like.
[0034]
The organic cyclic compound having a conjugated double bond of the catalyst component a3 is one or two or more rings having two or more, preferably two to four, more preferably two to three conjugated double bonds. A cyclic hydrocarbon compound having 4 to 24 carbon atoms, preferably 4 to 12 carbon atoms; wherein the cyclic hydrocarbon compound is partially a hydrocarbon residue having 1 to 6 carbon atoms (typically, 1 to 6 carbon atoms). A cyclic hydrocarbon compound substituted with 12 or more alkyl groups or aralkyl groups; having one or more rings having two or more, preferably two to four, more preferably two to three conjugated double bonds. An organosilicon compound having a cyclic hydrocarbon group having a total carbon number of 4 to 24, preferably 4 to 12; a hydrocarbon residue or an alkali metal salt (sodium) in which the cyclic hydrocarbon group is partially 1 to 6 Or lithium salt) The organosilicon compound is contained. Particularly preferably, those having a cyclopentadiene structure in any of the molecules are desirable.
[0035]
Examples of suitable compounds include cyclopentadiene, indene, azulene, and alkyl, aryl, aralkyl, alkoxy or aryloxy derivatives thereof. Further, a compound obtained by bonding (crosslinking) these compounds via an alkylene group (the number of carbon atoms of which is usually 2 to 8, preferably 2 to 3) is also preferably used.
[0036]
The organosilicon compound having a cyclic hydrocarbon group can be represented by the following general formula.
A_LSiR_4-L
Here, A represents the cyclic hydrogen group exemplified by a cyclopentadienyl group, a substituted cyclopentadienyl group, an indenyl group, and a substituted indenyl group, and R represents a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group. An alkyl group such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group; an aryl group such as a phenyl group; an aryloxy group such as a phenoxy group; an aralkyl group such as a benzyl group; Represents 24 to 24, preferably 1 to 12 hydrocarbon residues or hydrogen, and L is 1 ≦ L ≦ 4, preferably 1 ≦ L ≦ 3.
[0037]
Specific examples of the organic cyclic hydrocarbon compound of the component a3 include cyclopentadiene, methylcyclopentadiene, ethylcyclopentadiene, propylcyclopentadiene, butylcyclopentadiene, 1,3-dimethylcyclopentadiene, and 1-methyl-3-ethylcyclopentadiene. , 1-methyl-3-propylcyclopentadiene, 1-methyl-3-butylcyclopentadiene, 1,2,4-trimethylcyclopentadiene, pentamethylcyclopentadiene, indene, 4-methyl-1-indene, 4,7- C5-C24 cyclopolyene or substituted cyclopolyene such as dimethylindene, cycloheptatriene, methylcycloheptatriene, cyclooctatetraene, azulene, fluorene, methylfluorene, monocyclope Tajienirushiran, biscyclopentadienyl silane, tris cyclopentadienyl silane, mono indenyl silane, bis indenyl silane, and tris indenyl silane.
[0038]
The modified organoaluminum oxy compound containing an Al—O—Al bond of the catalyst component a4 is obtained by reacting an alkylaluminum compound with water to obtain a modified organoaluminum oxy compound usually called aluminoxane. It usually contains 1 to 100, preferably 1 to 50 Al-O-Al bonds. The modified organic aluminum oxy compound may be linear or cyclic.
[0039]
The reaction between the organoaluminum and water is usually performed in an inert hydrocarbon. As the inert hydrocarbon, aliphatic, alicyclic, and aromatic hydrocarbons such as pentane, hexane, heptane, cyclohexane, benzene, toluene, and xylene are preferable.
The reaction ratio (water / Al molar ratio) between water and the organoaluminum compound is usually from 0.25 / 1 to 1.2 / 1, preferably from 0.5 / 1 to 1/1.
[0040]
Examples of the boron compound include triethylaluminum tetra (pentafluorophenyl) borate, triethylammonium tetra (pentafluorophenyl) borate, dimethylanilinium tetra (pentafluorophenyl) borate, dimethylaniliniumtetra (pentafluorophenyl) borate, butyl Ammonium tetra (pentafluorophenyl) borate, N, N-dimethylaniliniumtetra (pentafluorophenyl) borate, N, N-dimethylaniliniumtetra (3,5-difluorophenyl) borate, trityltetrakispentafluoroborate, ferrose Ium tetrakispentafluoroborate, trispentafluoroborane and the like. Among them, N, N-dimethylanilinium tetra (pentafluorophenyl) borate, trityltetrakispentafluoroborate, ferrocenium tetrakispentafluoroborate, and trispentafluoroborane are preferable.
[0041]
The above catalyst may be used by mixing and contacting a1 to a4, but it is preferable to use the catalyst by supporting it on an inorganic carrier and / or a particulate polymer carrier (a5).
Examples of the inorganic carrier and / or the particulate polymer carrier (a5) include a carbonaceous material, a metal, a metal oxide, a metal chloride, a metal carbonate, a mixture thereof, a thermoplastic resin, and a thermosetting resin. Suitable metals that can be used for the inorganic carrier include iron, aluminum, nickel and the like.
Specifically, SiO₂, Al₂O₃, MgO, ZrO₂, TiO₂, B₂O₃, CaO, ZnO, BaO, ThO₂And mixtures thereof.₂-Al₂O₃, SiO₂-V₂O₅, SiO₂-TiO₂, SiO₂-MgO, SiO₂−Cr₂O₃And the like. Among them, SiO₂And Al₂O₃The main component is preferably at least one component selected from the group consisting of:
In addition, as the organic compound, any of a thermoplastic resin and a thermosetting resin can be used. Specifically, particulate polyolefin, polyester, polyamide, polyvinyl chloride, polymethyl (meth) acrylate, polystyrene, poly Examples include norbornene, various natural polymers, and mixtures thereof.
[0042]
The above-mentioned inorganic carrier and / or particulate polymer carrier can be used as they are, but preferably, as a pretreatment, these carriers are contact-treated with an organoaluminum compound or a modified organoaluminum compound containing an Al-O-Al bond. After that, it can be used as the component a5.
[0043]
The ethylene (co) polymer (A) is produced in the presence of the catalyst by a gas phase polymerization method, a slurry polymerization method, a solution polymerization method, or the like in which substantially no solvent is present, and substantially excludes oxygen, water, and the like. Hydrocarbons such as butane, pentane, hexane, heptane and the like, aromatic hydrocarbons such as benzene, toluene, xylene, and the like, and inactive hydrocarbons such as alicyclic hydrocarbons such as cyclohexane and methylcyclohexane It is produced in the presence or absence of a solvent. The polymerization conditions are not particularly limited, but the polymerization temperature is usually 15 to 350 ° C., preferably 20 to 200 ° C., more preferably 50 to 110 ° C., and the polymerization pressure is usually normal pressure to 70 kg / cm in the case of the low and medium pressure method.²G, preferably normal pressure to 20 kg / cm²G, usually 1500 kg / cm for high pressure method²G or less is desirable. The polymerization time is usually from 3 minutes to 10 hours, preferably from 5 minutes to 5 hours in the case of the low and medium pressure method. In the case of the high-pressure method, it is usually 1 minute to 30 minutes, preferably 2 minutes to 20 minutes. In addition, the polymerization is not particularly limited to a one-stage polymerization method and a multi-stage polymerization method of two or more stages in which polymerization conditions such as a hydrogen concentration, a monomer concentration, a polymerization pressure, a polymerization temperature, and a catalyst are different from each other. As a particularly preferred production method, a method described in JP-A-5-132518 is exemplified.
[0044]
The ethylene (co) polymer (A) has a halogen concentration of at most 10 ppm, preferably at most 5 ppm, more preferably substantially at least, by using a catalyst having no halogen such as chlorine in the above-mentioned catalyst components. (ND: 2 ppm or less). By using such a halogen-free ethylene (co) polymer (A) such as chlorine, it is not necessary to use a conventional acid neutralizer (halogen absorber) such as calcium stearate, hydrotalcite and the like. .
[0045]
[Other polyolefin resin (B)]
In the present invention, the other polyolefin-based resin (B) has a density different from that of the above-mentioned ethylene (co) polymer (A) from 0.86 to 0.97 g / cm.³Ethylene homopolymer or ethylene-α-olefin copolymer (hereinafter referred to as ethylene-based polymer), ethylene (co) polymer obtained by radical polymerization method, polypropylene, polybutene-1, poly4-methyl- Penten-1, ethylene-α-olefin copolymer rubber (EPR, EPDM, etc.) and the like.
[0046]
Examples of the ethylene polymer include a conventionally known Ziegler catalyst or Phillips catalyst (hereinafter, referred to as a Ziegler catalyst), or an ethylene homopolymer or ethylene-α-olefin polymerized using a metallocene catalyst. And copolymers. Such an ethylene polymer generally has a wider molecular weight distribution or composition distribution than the ethylene (co) polymer (A), and has a density of 0.88 to 0.97 g / cm.³, MFR in the range of 0.1 to 100 g / 10 min is preferable, and so-called very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), and high density polyethylene (HDPE) Is included.
[0047]
Medium / high-density polyethylene (HDPE) with a Ziegler-type catalyst etc. has a density of 0.94 to 0.97 g / cm³直 鎖, and linear low-density polyethylene (LLDPE) has a density of 0.91 to 0.94 g / cm³And the MFR is in the range of 0.01 to 100 g / 10 min, preferably 0.05 to 50 g / 10 min, and more preferably 0.1 to 30 g / 10 min. The melt tension is 0.3 to 40 g, preferably 0.4 to 35 g, more preferably 0.5 to 30 g. Mw / Mn is 2.5-13, preferably 3-10.
[0048]
Ultra low density polyethylene (VLDPE) using a Ziegler type catalyst or the like means that the density is 0.86 to 0.91 g / cm.³Less than, preferably 0.88 to 0.905 g / cm³, MFR is in the range of 0.01 to 100 g / 10 min, preferably 0.1 to 50 g / 10 min. Ultra-low density polyethylene (VLDPE) shows intermediate properties between linear low-density polyethylene (LLDPE) and ethylene-α-olefin copolymer rubber (EPR, EPDM). Ultra low density polyethylene (VLDPE) has a maximum peak temperature (Tm) by differential scanning calorimetry (DSC) of 60 ° C. or more, preferably 100 ° C. or more, and a boiling n-hexane insoluble content of 10% by mass or more. Is a specific ethylene-α-olefin copolymer having the formula: polymerized using a catalyst comprising at least a solid catalyst component containing at least titanium and / or vanadium and an organoaluminum compound; linear low-density polyethylene (LLDPE) Is a resin having both a high crystalline portion represented by the formula and an amorphous portion represented by the ethylene-α-olefin copolymer rubber. Such ultra-low density polyethylene (VLDPE) has the mechanical strength and heat resistance characteristic of linear low density polyethylene (LLDPE) and the rubber-like elasticity characteristic of ethylene-α-olefin copolymer rubber. And low-temperature impact resistance coexist in a well-balanced manner.
[0049]
The α-olefin of the ethylene-α-olefin copolymer with a Ziegler catalyst has 3 to 12 carbon atoms, preferably 3 to 10 carbon atoms, and specifically includes propylene, 1-butene, and 4-methyl. -1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene and the like. In addition, the content of these α-olefins is preferably selected in a range of usually 3 to 40 mol% in total.
[0050]
Examples of the ethylene (co) polymer obtained by the radical polymerization method include low-density polyethylene (LDPE) by high-pressure radical polymerization, an ethylene-vinyl ester copolymer, ethylene and an α, β-unsaturated carboxylic acid or a derivative thereof. And the like.
[0051]
The MFR of low density polyethylene (LDPE) is in the range of 0.01 to 100 g / 10 min, more preferably 0.1 to 50 g / 10 min, and even more preferably 0.5 to 30 g / 10 min. Within this range, the melt tension will be in an appropriate range, and foamability, moldability, etc. will be good. The density is 0.91 to 0.94 g / cm³, More preferably 0.912 to 0.935 g / cm³範 囲 range. Within this range, the melt tension will be in an appropriate range, and foamability will be improved. The melt tension is 1.5 to 25 g, preferably 3 to 20 g, more preferably 3 to 15 g. Further, the molecular weight distribution Mw / Mn is 3.0 to 12, preferably 4.0 to 8.0. Melt tension is an elasticity item of the resin, and the foamability is good in the above range.
[0052]
The ethylene-vinyl ester copolymer is mainly composed of ethylene produced by a high-pressure radical polymerization method, ethylene and vinyl propionate, vinyl acetate, vinyl caproate, vinyl caprylate, vinyl laurate, vinyl stearate, It is a copolymer with a vinyl ester monomer such as vinyl trifluoroacetate. Among them, particularly preferred is vinyl acetate. Further, a copolymer comprising 50 to 99.5% by mass of ethylene, 0.5 to 50% by mass of a vinyl ester, and 0 to 49.5% by mass of another copolymerizable unsaturated monomer is preferable. In particular, the content of the vinyl ester is in the range of 3 to 30% by mass, preferably 5 to 25% by mass. The MFR of the ethylene-vinyl ester copolymer is in the range of 0.01 to 100 g / 10 min, more preferably 0.05 to 50 g / 10 min, and further preferably 0.1 to 30 g / 10 min, and the melt tension is 2 0.0-25 g, preferably 3-20 g.
[0053]
Examples of the copolymer of ethylene and an α, β-unsaturated carboxylic acid or a derivative thereof include an ethylene-maleic anhydride copolymer, an ethylene- (meth) acrylic acid or an alkyl ester copolymer thereof, and the like. Examples of the comonomer include maleic anhydride, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, and n-acrylate. -Butyl, n-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, glycidyl acrylate, glycidyl methacrylate, and the like. it can. Of these, particularly preferred are maleic anhydride and alkyl esters of (meth) acrylic acid such as methyl and ethyl. In particular, the content of the (meth) acrylate is in the range of 3 to 30% by mass, preferably 5 to 25% by mass. The MFR of a copolymer of ethylene and an α, β-unsaturated carboxylic acid or a derivative thereof has an MFR of 0.01 to 100 g / 10 min, more preferably 0.05 to 50 g / 10 min, and still more preferably 0.1 to 30 g. / 10, and the melt tension is 2.0 to 25 g, preferably 3 to 20 g.
[0054]
Examples of the polypropylene-based resin include homopolypropylene and propylene-ethylene copolymer. The MFR of the polypropylene-based resin is in the range of 0.1 to 100 g / 10 minutes, preferably 0.2 to 50 g / 10 minutes. Within this range, the melt tension will be in an appropriate range, and foamability will be improved.
Examples of the ethylene-α-olefin copolymer rubber include ethylene propylene rubber (EPR), ethylene-propylene-diene terpolymer (EPDM), and ethylene-butene-1 copolymer rubber.
[0055]
The type of the other polyolefin-based resin (B) used in the present invention varies depending on the characteristics required for the foamed molded article. Among these other polyolefin-based resins (B), high-density polyethylene and polypropylene-based resins are preferably used from the viewpoint of imparting excellent heat resistance of the foamed molded article.
[0056]
A preferred embodiment of the present invention is a composition comprising 100 to 5% by mass of an ethylene (co) polymer (A) and 0 to 95% by mass of a high-density polyethylene as another polyolefin-based resin (B). More preferably, the ethylene (co) polymer (A) is in the range of 80 to 20% by mass and the high-density polyethylene is in the range of 20 to 80% by mass, and more preferably the ethylene (co) polymer (A) is 70 to 40% by mass, Polyethylene is 30 to 60% by mass. When the composition is in this range, a foam having a well-balanced processability at the time of foaming, heat resistance, mechanical strength, uniformity of foam cells, etc. is provided.
[0057]
Various additives, compounding agents, and fillers can be used in the resin component containing the ethylene (co) polymer (A) as long as the purpose is not impaired. If these are specifically shown, antioxidants (heat stabilizers), ultraviolet absorbers (light stabilizers), antistatic agents, tackifiers, antifogging agents, flame retardants, lubricants (slip agents, antiblocking agents) , Coloring agents (dyes and pigments), fragrances and the like.
[0058]
[Blowing agent (C)]
Examples of the foaming agent (C) include (C1) a pyrolytic foaming agent and (C2) a gas foaming agent.
Examples of the thermal decomposition type foaming agent include an organic thermal decomposition type foaming agent such as an azo or diazo compound, a nitroso compound and a sulfonic acid hydrazide compound, and an inorganic thermal decomposition type foaming agent. Specifically, azo or diazo compounds include azodicarbonamide, azobisisobutyronitrile, diazoaminobenzene, barium-azodicarboxylate, trihydrazinotriazine, p-toluenesulfonyl semicarbazide, 4,4 '-Oxybisbenzenesulfonyl semicarbazite and the like.
Examples of the nitroso compound include N, N'-nitrosopentamethylenetetramine, N, N'-dimethyl-N, N'-dinitrosoterephthalamide, and the like.
[0059]
Examples of the sulfonic acid hydrazide compound include 4,4'-oxybisbenzenesulfonyl hydrazide, p-toluenesulfonyl hydrazide, benzenesulfonyl hydrazide, diphenylsulfone-S, S'-disulfonyl hydrazide and the like.
As other organic thermal decomposition type foaming agents, organic thermal decomposition type foaming agents such as nitroguanine and 5-phenyltetrazole can be mentioned.
Examples of the inorganic pyrolytic foaming agent include sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, sodium hydrogen carbonate, anhydrous sodium citrate, peroxides, azide compounds, sodium and potassium borohydride, and the like.
[0060]
In addition, the gas type blowing agent includes carbon dioxide gas, nitrogen gas, air, H₂Inorganic foaming agents such as O, and organic solvent type foaming agents such as pentane, acetone, hexane, benzene, heptane, freon, trichlorotrifluoroethane, petroleum ether, and isohexane.
Among them, azodicarbonamide, carbon dioxide gas and the like are particularly preferably used. These foaming agents can be used alone or in combination of two or more.
The decomposition temperature of the pyrolytic foaming agent is in the range of 100 to 240 ° C., and thermal decomposition occurs in this range.
[0061]
The amount of the foaming agent (C) is in the range of 0.5 to 20 parts by mass based on 100 parts by mass of the resin component containing the ethylene (co) polymer (A) and the other polyolefin-based resin (B). . When the expansion ratio is in the range of 1.2 to 10 times, it is desirable that the blowing agent (C) is blended in the range of 0.5 to 10 parts by mass, preferably 1 to 7 parts by mass.
[0062]
[Preparation of polyolefin resin composition for foaming]
The polyolefin resin composition for foaming of the present invention in an uncrosslinked and unfoamed state may be in a molten state, or may be a pellet or sheet solidified by cooling.
The pellets of the polyolefin-based resin composition for foaming of the present invention are prepared, for example, by mixing an ethylene (co) polymer (A), another polyolefin-based resin (B), and a pyrolytic foaming agent in the above-described ratio with a Henschel mixer or the like. Then, it can be melt-plasticized by a kneading machine such as a Banbury mixer or an extruder at a temperature at which the pyrolytic foaming agent does not decompose, uniformly mixed and dispersed, and prepared by a granulator.
[0063]
In the polyolefin resin composition for foaming, in addition to the ethylene (co) polymer (A), the other polyolefin resin (B) and the pyrolytic foaming agent, optionally, a foaming aid, a crosslinking agent, and a crosslinking agent. Conventionally known additives such as auxiliaries, heat stabilizers, weather stabilizers, pigments, fillers, lubricants, antistatic agents, flame retardants and the like can be blended within a range that does not impair the object of the present invention.
[0064]
Specific examples of the foaming aid include metal oxides such as zinc oxide and lead oxide; metal carbonates such as zinc carbonate; metal chlorides such as zinc chloride; urea; zinc stearate, lead stearate; Metal soaps such as lead stearate, zinc laurate, zinc 2-ethylhexoate, and dibasic lead phthalate; organic tin compounds such as dibutyltin dilaurate and dibutyltin dimaleate; tribasic lead sulfate and dibasic phosphorous acid Inorganic salts such as lead oxide and basic lead sulfite; dibutyltin dilaurate-based, dibutyltin dimaleate-based, calcium-zinc-based, barium-zinc-based composite stabilizers for polyvinyl chloride (PVC), talc, and the like. it can. This composite stabilizer for polyvinyl chloride is used for the purpose of controlling the decomposition temperature of the blowing agent and imparting thermal stability.
[0065]
A cross-linking agent (radical generator) may be used when preparing a cross-linked foam. Specifically, dicumyl peroxide, benzoyl peroxide, di-t-butyl peroxide, 2,5-dimethyl -2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne, 2,5-dimethyl-2,5-di (t-butyl Organic peroxides such as peroxy) hexane-3, lauroyl peroxide, t-butylperoxybenzoate, and dicumyl peroxide.
[0066]
When using a crosslinking agent, a crosslinking aid may be used in combination. Specific examples of the crosslinking assistant include triallyl cyanurate (TAC) and triallyl isocyanurate (TAIC).
[0067]
An uncrosslinked and unfoamed foamable sheet made of the polyolefin resin composition for foaming is formed, for example, by molding pellets of the composition obtained as described above using an extruder or a calender molding machine. Obtainable. Alternatively, an uncrosslinked and unfoamed foamable sheet can be obtained by, for example, kneading various components of the foaming polyethylene resin composition with a Brabender or the like, and then forming the sheet through a T-die or an annular die.
[0068]
[Manufacture of foam molding]
The foamed molded article of the present invention is obtained, for example, from a pellet of the polyolefin resin composition for foaming prepared as described above or a molten resin in an unfoamed state by extrusion molding or injection molding, etc. Producing a desired foamable molded article, for example, a foamable sheet at a temperature lower than the decomposition temperature, and then producing the foamable sheet by heating and foaming at a temperature not lower than the temperature at which the pyrolytic foaming agent thermally decomposes. Can be. In the present invention, the temperature equal to or higher than the temperature at which the thermal decomposition type foaming agent is thermally decomposed is 100 to 240 ° C.
As another method for producing the foamed molded article of the present invention, when an inert gas (gas-type foaming agent) such as nitrogen or carbon dioxide is used, the inert gas is extruded into a molten resin in an extruder. There is also a method of injecting from the machine side into a foamed molded body.
[0069]
In the present invention, if a resin composition containing an ethylene (co) polymer (A) and another polyolefin-based resin (B) is previously crosslinked, a crosslinked foam made of crosslinked polyethylene, for example, a crosslinked foam sheet Can be obtained.
As a method of performing such crosslinking, generally, a crosslinking agent (radical generation) mixed in a resin composition containing (i) an ethylene (co) polymer (A) and another polyolefin resin (B) is used. Of the resin composition by thermal decomposition of the agent), (ii) a crosslinking method by irradiation with ionizing radiation, (iii) a crosslinking by irradiation with ionizing radiation in the presence of a polyfunctional monomer, and (iv) a silane crosslinking. And the like.
[0070]
In order to obtain a cross-linked foam by the cross-linking method (i), first, an ethylene (co) polymer (A), another polyolefin resin (B) and a foaming agent (C), an organic peroxide (cross-linking agent) and other Is melt-kneaded at a temperature lower than the decomposition temperature of the foaming agent (C), and the resulting kneaded product is molded into, for example, a sheet to obtain a foamable sheet.
Next, the obtained foamable sheet is heated at a temperature at which the organic peroxide decomposes and at a temperature lower than the decomposition temperature of the foaming agent (C) to crosslink the composition. The crosslinked sheet is foamed by heating it to a temperature equal to or higher than the decomposition temperature of the foaming agent (C).
[0071]
In order to obtain a cross-linked foam by the cross-linking method by irradiation of ionizing radiation in (ii), first, an ethylene (co) polymer (A), another polyolefin resin (B) and a foaming agent (C) are required. The other additives are melt-kneaded at a temperature lower than the decomposition temperature of the foaming agent (C), and the resulting kneaded material is formed into, for example, a sheet to obtain a foamable sheet.
Next, the obtained foamable sheet is irradiated with a predetermined amount of ionizing radiation to crosslink the resin composition containing the ethylene (co) polymer (A), and then the obtained foamable crosslinked sheet is subjected to a blowing agent (C The crosslinked foamed sheet can be obtained by foaming by heating at or above the decomposition temperature of (1).
[0072]
As the ionizing radiation, α-rays, β-rays, γ-rays, electron beams, neutron rays, X-rays and the like are used. Of these, gamma rays and electron beams of cobalt-60 are preferably used. The dose of the ionizing radiation is about 1 to 20 Mrad, preferably 2 to 18 Mrad, and the expansion ratio of the obtained crosslinked foam is 1.2 to 30 times, preferably 2 to 10 times. It is desirable that the irradiation amount is appropriate.
[0073]
When an inert gas is used, carbon dioxide gas, nitrogen gas, or the like is injected into the zone where the resin is in a molten state in the extruder from the middle of the extruder to form a foam molded article.
Examples of the product shape of the foam molded article of the present invention include a sheet shape, a thick board shape, a net shape, and a mold.
[0074]
The foam molded article of the present invention comprises a polyolefin resin composition containing a specific ethylene (co) polymer (A), another polyolefin resin (B) and a foaming agent (C) at a specific ratio. Therefore, they are excellent in foaming characteristics, flexibility, mechanical strength such as tear strength, and the like. In particular, the crosslinked foam has better appearance and the like than the non-crosslinked foam.
[0075]
Such a foamed molded article is excellent in flexibility, mechanical strength such as tear strength, etc., and is formed by bleeding of additives such as low molecular weight components and chlorine catchers such as calcium stearate (CaSt) and zinc stearate (ZnSt). The generation of dust is small, and it is particularly suitable for applications such as heat insulating materials, cushioning materials, flooring materials, and interior materials that are suitable for fields such as medical care, electronics, and food packaging.
[0076]
【Example】
Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.
The test method of the resin composition in this example was performed according to the following test method.
[density]
It conformed to JIS K692-2-2.
[MFR]
It conformed to JIS K692-2-2.
[0077]
[Mw / Mn]
GPC (150C type manufactured by Waters) was used, and ODCB at 135 ° C. was used as a solvent. The column used was Showdex @ HT806M.
[0078]
[TREF]
With the column kept at 140 ° C., the sample was injected into the column, the temperature was lowered to 25 ° C. at 4 ° C./h, and the polymer was deposited on the glass beads. The concentration of the polymer eluted at the temperature was detected by an infrared detector. (Solvent: ODCB, flow rate: 1 ml / min, heating rate: 50 ° C./hr, detector: infrared spectrometer (wavelength: 2925 cm)^-1), Column: 0.8 cmφ × 12 cmL (filled with glass beads), sample concentration: 0.1% by mass)
[0079]
[ODCB soluble content X]
0.5 g of the sample is heated at 135 ° C. for 2 hours in 20 ml of ODCB to completely dissolve the sample and then cooled to 25 ° C. After leaving this solution at 25 ° C. overnight, the solution is filtered through a Teflon (registered trademark) filter, and the filtrate is collected. This filtrate, which is a sample solution, was subjected to infrared spectroscopy to measure the asymmetric stretching vibration of methylene with a wave number of 2925 cm.^-1The intensity of the nearby absorption peak was measured, and the sample concentration was calculated from a calibration curve created in advance. From this value, the ODCB-soluble content at 25 ° C. was determined.
[0080]
[Measurement of Tml by DSC]
A sheet having a thickness of 0.2 mm was formed by hot pressing, and a sample of about 5 mg was punched from the sheet. After holding this sample at 230 ° C. for 10 minutes, it was cooled to 0 ° C. at 2 ° C./min. Thereafter, the temperature was raised again to 170 ° C. at 10 ° C./min, and the temperature at the top of the highest temperature peak that appeared was defined as the highest peak temperature Tml.
[0081]
[Melt tension (MT)]
The stress when the melted polymer was stretched at a constant speed was determined by measuring with a strain gauge. The measurement sample was granulated into pellets and measured using an MT measuring device manufactured by Toyo Seiki Seisaku-sho. The orifice used has a hole diameter of 2.09 mmφ and a length of 8 mm. The measurement conditions are a resin temperature of 190 ° C., a cylinder descending speed of 20 mm / min, and a winding speed of 15 m / min.
[0082]
[Halogen concentration]
It was measured by a fluorescent X-ray method, and when chlorine of 10 ppm or more was detected, this was used as an analysis value. When it was less than 10 ppm, it was measured with a TOX-100 type chlorine / sulfur analyzer manufactured by Dia Instruments Co., Ltd., and when it was 2 ppm or less, it was regarded as ND and was not substantially contained.
[0083]
Various components used in the examples are as follows.
[Ethylene (co) polymer (A)]
The ethylene (co) polymer (A1) was polymerized by the following method.
(Preparation of solid catalyst)
(Solid catalyst)
In a catalyst preparation device equipped with an electromagnetic induction stirrer, 1000 ml of toluene purified under nitrogen, tetrapropoxyzirconium (Zr (OPr)₄Ii) 26 g, 22 g of indene and 88 g of methylbutylcyclopentadiene were added, 100 g of tripropylaluminum was added dropwise over 100 minutes while maintaining the temperature at 90 ° C., and the mixture was reacted at the same temperature for 2 hours. After cooling to 40 ° C., 2,424 ml of a toluene solution of methylalumoxane (concentration: 3.3 mmol / ml) was added, and the mixture was stirred for 2 hours. Next, silica (calculated at 450 ° C. for 5 hours)²/ G), and after stirring at room temperature for 1 hour, nitrogen blowing and drying under reduced pressure were performed at 40 ° C. to obtain a solid catalyst (a) having good fluidity.
[0084]
(Gas phase polymerization)
Using a continuous fluidized bed gas phase polymerization apparatus, polymerization temperature 65 ° C, total pressure 20kgf / cm²The copolymerization of ethylene and 1-hexene was performed at ΔG. The solid catalyst (a) was continuously supplied, and ethylene, 1-hexene, hydrogen, and the like were supplied so as to be maintained at a predetermined molar ratio to carry out polymerization to obtain an ethylene copolymer (A11) (sLLDPE). . Table 1 shows the measurement results of the physical properties of the copolymer.
[0085]
(Preparation of solid catalyst)
(Solid catalyst)
In a catalyst preparation device equipped with an electromagnetic induction stirrer, 1000 ml of toluene purified under nitrogen, tetrabutoxyzirconium (Zr (OBu))₄Ii) 31 g and 74 g of indene were added, and while maintaining the temperature at 90 ° C., 127 g of triisobutylaluminum was added dropwise over 100 minutes, followed by a reaction at the same temperature for 2 hours. After cooling to 40 ° C., 2424 ml of a toluene solution of methylalumoxane (concentration: 3.3 mmol / ml) was added, and the mixture was stirred for 2 hours. Next, silica (calculated at 450 ° C. for 5 hours)²/ G), and after stirring at room temperature for 1 hour, nitrogen blowing and drying under reduced pressure were performed at 40 ° C. to obtain a solid catalyst (b) having good fluidity.
[0086]
(Gas phase polymerization)
Using a continuous fluidized-bed gas-phase polymerization apparatus, polymerization temperature 70 ° C., total pressure 20 kgf / cm²The copolymerization of ethylene and 1-hexene was performed at ΔG. The solid catalyst (b) was continuously supplied, and polymerization was performed by supplying ethylene, 1-hexene and hydrogen at a predetermined molar ratio to obtain an ethylene copolymer (A12) (sLLDPE). . Table 1 shows the measurement results of the physical properties of the copolymer.
[0087]
The ethylene (co) polymer (A2) was polymerized by the following method.
(Preparation of solid catalyst)
(Solid catalyst)
In a catalyst preparation device equipped with an electromagnetic induction stirrer, 1000 ml of toluene purified under nitrogen, tetrapropoxyzirconium (Zr (OPr)₄Ii) 26 g, 74 g of indene and 78 g of methylpropylcyclopentadiene were added, and 100 g of tripropylaluminum was added dropwise over 100 minutes while maintaining the temperature at 90 ° C., followed by a reaction at the same temperature for 2 hours. After cooling to 40 ° C., 2133 ml of a toluene solution of methylalumoxane (concentration: 3.3 mmol / ml) was added, and the mixture was stirred for 2 hours. Next, silica (calculated at 450 ° C. for 5 hours)²/ G), and after stirring at room temperature for 1 hour, nitrogen blowing and drying under reduced pressure were performed at 40 ° C. to obtain a solid catalyst (c) having good fluidity.
[0088]
(Gas phase polymerization)
Using a continuous fluidized-bed gas-phase polymerization apparatus, polymerization temperature 80 ° C., total pressure 20 kgf / cm²The copolymerization of ethylene and 1-hexene was performed at ΔG. The solid catalyst (c) was continuously supplied, and ethylene, 1-hexene and hydrogen were supplied so as to be maintained at a predetermined molar ratio to carry out polymerization to obtain an ethylene copolymer (A2) (sLLDPE). Table 1 shows the measurement results of the physical properties of the copolymer.
[0089]
(A3) Ethylene-hexene-1 copolymer with general metallocene catalyst
Purified toluene was placed in a pressurized reactor equipped with a stirrer replaced with nitrogen, 1-hexene was added, and a mixed liquid of bis (n-butylcyclopentadienyl) zirconium dichloride and methylalumoxane (MAO) was further added. After adding (Al / Zr molar ratio = 500), the temperature was raised to 80 ° C. to prepare a metallocene catalyst. Then, ethylene was added, and the total pressure was 6 kg / cm while continuously polymerizing ethylene.²The polymerization was carried out while maintaining the temperature at to produce an ethylene / hexene-1 copolymer (referred to as mLLDPE). Table 1 shows the measurement results of the physical properties of the copolymer.
[0090]
(A4) Commercial linear low density polyethylene with Ziegler catalyst
Density: 0.910 g / cm³, MFR: 10 g / 10 min, comonomer: 4-methyl-1-pentene
Table 1 shows the measurement results of physical properties of the copolymer (referred to as zLLDPE).
[0091]
[Table 1]

[0092]
[Other polyolefin resin (B)]
Commercially available high-density polyethylene (HDPE)
Density: 0.951 g / cm³Ｍ, MFR: 0.3 g / 10 min (trade name: J-LEX-HD KV175N, manufactured by Nippon Polyolefin Co., Ltd.)
[0093]
[Example 1]
1.0 parts by mass of sodium hydrogencarbonate as a foaming agent, 1.0 parts by mass of anhydrous citric acid monosodium, and 0.03 parts by mass of talc (foaming nucleating agent) as a foaming aid, per 100 parts by mass of the ethylene copolymer (A11) Was melt-kneaded by a twin-screw extruder (65 mm in diameter), and extruded at a temperature of 140 ° C. from a coat hanger type T-die connected to the extruder to obtain a foam sheet having a thickness of about 2 mm. Table 2 shows the results of measuring the apparent density, tensile strength, and the like of the obtained foamed sheet.
The test method is as follows.
[0094]
[Apparent density]
It was measured by an electronic hydrometer (MD-200S manufactured by Mirage).
[Bubble uniformity]
The cross section of the foamed sheet was visually observed with the naked eye. When the bubbles were uniform, the sample was evaluated as 若干, when the samples were slightly non-uniform, and Δ, and when the samples were non-uniform, ×.
[0095]
[Tensile test]
In accordance with ASTM D638, a tensile test was performed on the foamed sheet under the conditions of 50 mm / min, and the tensile strength at break and the elongation at break were measured.
[Tear test]
According to JIS K6767, the tear strength was measured at a speed of 500 mm / min by using a clave method tear test.
[0096]
[Examples 2 to 6]
A foamed sheet was obtained and evaluated in the same manner as in Example 1, except that the high-density polyethylene of the component (B) was mixed with the ethylene copolymer (A11) of the component (A) in the composition shown in Table 2. The results are shown in Table 2.
[0097]
[Examples 7 to 9]
According to Example 6, except that the ethylene copolymer (A11) as the component (A) was replaced with an ethylene copolymer (A12), an ethylene copolymer (A2), and an ethylene copolymer (A3). The foamed sheet was obtained and the evaluation results are shown in Table 2.
[0098]
[Table 2]

[0099]
[Comparative Examples 1 to 6]
According to Example 1, except that the ethylene copolymer (A11) of the component (A) was replaced with another ethylene copolymer (A4) and the high-density polyethylene of the component (B) was mixed with the composition shown in Table 2. Thus, a foamed sheet was obtained, and the evaluation results are shown in Table 3.
[0100]
[Table 3]

[0101]
【The invention's effect】
As described above, the polyolefin resin composition for foaming of the present invention comprises 100 to 5% by mass of an ethylene (co) polymer (A) satisfying the above requirements (a) to (d) and another polyolefin. Since the resin component contains 0 to 95% by mass of the resin (B) and 0.5 to 20 parts by mass of the foaming agent (C) with respect to 100 parts by mass of the resin component, a conventional polyethylene-based resin is used. Excellent foaming properties, flexibility, mechanical strength such as tear strength, etc., compared to resin foam, and low dust generation due to bleeding of additives such as low molecular weight components and chlorine catchers such as calcium stearate and zinc stearate. A foam molded article suitable for medical, electronics, food packaging and other fields can be provided.
[Brief description of the drawings]
FIG. 1 is a graph showing an elution temperature-elution amount curve of an ethylene (co) polymer (A) according to the present invention.
FIG. 2 is a graph showing an elution temperature-elution amount curve of an ethylene (co) polymer (A1) according to the present invention.
FIG. 3 is a graph showing an elution temperature-elution amount curve of an ethylene (co) polymer with a general metallocene catalyst.
FIG. 4 is a graph showing an elution temperature-elution amount curve of the ethylene (co) polymer (A2) according to the present invention.

Claims (13)

A resin component containing 100 to 5% by mass of an ethylene (co) polymer (A) and 0 to 95% by mass of another polyolefin resin (B) satisfying the following requirements (a) to (d): A foaming polyolefin-based resin composition containing 0.5 to 20 parts by mass of a foaming agent (C) based on 100 parts by mass.
(A) a density of 0.86 to 0.97 g / cm ³ ,
(B) a melt flow rate of 0.1 to 100 g / 10 minutes,
(C) a molecular weight distribution (Mw / Mn) of 1.5 to 4.5,
(D) elution temperature by continuous Atsushi Nobori elution fractionation (TREF) - the difference between the temperature T ₇₅ to 75% of the total temperature T ₂₅ to 25% of the total determined from the integral elution curve of elution amount curve is eluted elutes T ₇₅ −T ₂₅ and density d satisfy the relationship of the following (Equation 1) (Equation 1): T ₇₅ −T ₂₅ ≦ −670 × d + 644 The polyolefin resin composition for foaming according to claim 1, wherein the ethylene (co) polymer (A) further satisfies the following requirement (e).
(E) elution temperature by continuous Atsushi Nobori elution fractionation (TREF) - the difference between the temperature T ₇₅ to 75% of the total temperature T ₂₅ to 25% of the total was determined from integral溶曲line of elution curve is eluted elutes T ₇₅ -T ₂₅ and density d satisfy the following to satisfy the relation of (formula 2) (formula _{2) d <T 75 -T 25} ≧ -300 × d + 285 when 0.950 g / cm ³
When d ≧ 0.950 g / cm ³ , T ₇₅ −T ₂₅ ≧ 0 3. The ethylene (co) polymer (A1) according to claim 1 or 2, wherein the ethylene (co) polymer (A) satisfies the following requirements (f) and (g). Polyolefin resin composition for foaming.
(F) Orthodichlorobenzene (ODCB) soluble content X (mass%), density d and melt flow rate (MFR) at 25 ° C. satisfy the following formulas (formula 3) and (formula 4) (formula 3) d-0.008 log X <2.0 when MFR ≧ 0.93
(Equation 4) When d−0.008 log MFR <0.93, X <9.8 × 10 ³ × (0.9300−d + 0.008 log MFR) ² +2.0
(G) The presence of a plurality of peaks in the elution temperature-elution amount curve by the continuous temperature elution fractionation method (TREF) The said ethylene (co) polymer (A) is an ethylene (co) polymer (A2) which further satisfies the requirements of (h) and (i) below, 3 or 2 characterized by the above-mentioned. A polyolefin resin composition for foaming.
(H) One peak of the elution temperature-elution amount curve by the continuous heating elution fractionation method (TREF). (I) It has one or more melting point peaks, and the highest melting point Tml and density d are: Satisfies the following equation (Equation 5) (Equation 5) Tml ≧ 150 × d−19 The polyolefin resin composition for foaming according to claim 4, wherein the ethylene (co) polymer (A2) further satisfies the following requirement (j).
(J) Melt tension (MT) and melt flow rate (MFR) satisfy the following (Equation 6) (Equation 6) logMT ≦ −0.572 × logMFR + 0.3 The polyolefin resin composition for foaming according to any one of claims 1 to 5, wherein a halogen concentration in the ethylene (co) polymer (A) is 10 ppm or less. The ethylene (co) polymer (A) is produced by using a catalyst containing at least an organic cyclic compound having a conjugated double bond and a transition metal compound belonging to Group IV of the periodic table. 7. The polyolefin resin composition for foaming according to any one of 1 to 6. The polyolefin foam for foaming according to any one of claims 1 to 7, wherein the resin component comprises 5% by mass or more of an ethylene (co) polymer (A) and 95% by mass or less of high-density polyethylene. Resin composition. The polyolefin resin composition for foaming according to any one of claims 1 to 8, wherein the foaming agent (C) is a pyrolytic foaming agent or a gas foaming agent. . A foam molded article comprising the polyolefin resin composition for foaming according to any one of claims 1 to 9 and having a foaming ratio of 1.2 to 30 times. The foam molded article according to claim 10, which is a crosslinked foam. A resin component containing 100 to 5% by mass of an ethylene (co) polymer (A) and 0 to 95% by mass of another polyolefin resin (B) satisfying the following requirements (a) to (d): A foaming polyolefin-based resin composition containing 0.5 to 20 parts by mass of a thermal decomposition type foaming agent with respect to 100 parts by mass is molded, and the thermal decomposition type foaming agent is decomposed by heat to have an expansion ratio of 1. A method for producing a foamed molded article, which comprises obtaining a foamed molded article of 2 to 30 times.
(A) a density of 0.86 to 0.97 g / cm ³ ,
(B) a melt flow rate of 0.1 to 100 g / 10 minutes,
(C) a molecular weight distribution (Mw / Mn) of 1.5 to 4.5,
(D) elution temperature by continuous Atsushi Nobori elution fractionation (TREF) - the difference between the temperature T ₇₅ to 75% of the total temperature T ₂₅ to 25% of the total determined from the integral elution curve of elution amount curve is eluted elutes T ₇₅ −T ₂₅ and density d satisfy the relationship of the following (Equation 1) (Equation 1): T ₇₅ −T ₂₅ ≦ −670 × d + 644 When molding a resin component containing 100 to 5% by mass of an ethylene (co) polymer (A) satisfying the following requirements (a) to (d) and 0 to 95% by mass of another polyolefin-based resin (B): And a gas-type foaming agent is injected to obtain a foamed molded article having an expansion ratio of 1.2 to 30 times.
(A) a density of 0.86 to 0.97 g / cm ³ ,
(B) a melt flow rate of 0.1 to 100 g / 10 minutes,
(C) a molecular weight distribution (Mw / Mn) of 1.5 to 4.5,
(D) elution temperature by continuous Atsushi Nobori elution fractionation (TREF) - the difference between the temperature T ₇₅ to 75% of the total temperature T ₂₅ to 25% of the total determined from the integral elution curve of elution amount curve is eluted elutes T ₇₅ −T ₂₅ and density d satisfy the relationship of the following (Equation 1) (Equation 1): T ₇₅ −T ₂₅ ≦ −670 × d + 644

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