JP2005059891A - Buffering material for packaging - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a buffering material for packaging, which retains capabilities like lubricity, antiblocking property, etc., even if an additive is eliminated from the buffering material, prevents the formation of cell marks on an article to be packaged, and has improved compressive breakage resistant strength, piercing resistant strength, or the like. <P>SOLUTION: The buffering material 10 consists of a cell layer 14, on which a plurality of projections 16 are formed, and a film layer 12 sticking to the cell layer 14. The film layer 12 and/or the cell layer 14 contain (A) an ethylene polymer (copolymer) of 40 to 100 wt.%, which has a density, melt flow rate, and molecular weight distribution within a specific range and an elution temperature, given by a continuous temperature-programmed elution fractionating method, in a specific relation with the density, (B) a straight-chain low-density or a high-density polyethylene of 0 to 30 wt.%, which has a density of 0.93 to 0.96 g/cm<SP>3</SP>and a melt flow rate of 0.1 to 10 g/10min., and (C) a high-pressure radical method ethylene copolymer of 0 to 30 wt.%, which has a melt flow rate of 0.1 to 10 g/10min. The film layer 12 and/or the cell layer 14 is made of a resin composition having a density of 0.93 to 0.96 g/cm<SP>3</SP>and a melt flow rate of 1 to 10 g/10min. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cushioning material for packing (a so-called air chamber sheet) that is used as a packaging material for various articles, reduces the impact on the article, and is used as a heat insulating material.

A cushioning material for packing (so-called air chamber sheet) is widely used as a packaging material that reduces external force applied to various articles and is used as a heat insulating material.
As a cushioning material for packing, generally, a flat resin film and a resin film formed with protrusions to be a cell (air cell, air chamber) are laminated to have a plurality of sealed cells. There are two-layer structures and three-layer structures in which flat resin films are laminated on both sides of a resin film with protrusions that form cells as intermediate layers. Various thermoplastic resins, especially Polyolefins are known. Conventionally, as the polyolefin, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), or a mixture thereof is generally used.

Conventionally, LDPE having a density of about 0.920 g / cm ³ has been used as a cushioning material for packing such as chests, tableware, and automobile export parts. However, the cushioning material for packing made of LDPE has a problem that the puncture strength is low and it is easily broken.

  Air chamber sheets made of a mixture of LDPE, LLDPE and HDPE (polyethylene composition) are often used because of their excellent characteristics. However, such a polyethylene composition has a slip agent, an anti-molding agent, a mold release property, a slip agent and an anti Additives such as blocking agents, antistatic agents, and antioxidants were added to all layers having a 2-3 layer structure. For this reason, these additives bleed out on the film surface, and the cell part additive that comes into contact with the object to be packed is transferred to the object to be packed, leaving cell marks on the object to be packed, thereby reducing the commercial value. There was a problem that.

JP-A-11-170410 (Patent Document 1) discloses that (A) density is 0.935 g / cm ³ or less, melt flow rate (MFR) is 0.1 to 5 g / 10 min, and Z average molecular weight is 95 to 60% by mass of low density polyethylene by high pressure radical polymerization method having 3 to 15% by mass of 400,000 to 900,000 components, (B) density is 0.94 to 0.97 g / cm ³ , and MFR is 0.00. It contains 5 to 40% by mass of high density polyethylene of 01 to 50 g / 10 min, the density is 0.92 to 0.94 g / cm ³ , the MFR is 0.5 to 20 g / 10 min, and the melt tension is 4 to 4%. 12 g of resin composition and 0.01 to 0.5 parts by mass of at least a phosphorus-based antioxidant with respect to 100 parts by mass of the resin composition. Is described.
However, even in the air chamber sheet using the resin material for the air chamber sheet, a slip agent, an antiblocking agent, and an antistatic agent are usually required, and in this publication, transfer of the additive in the cell portion is prevented. The technical idea to do is not disclosed.

Japanese Patent Application Laid-Open No. 9-123320 (Patent Document 2) describes a cellular cushion sheet made of a plastic film having a predetermined density, MFR, ratio of MFR at different loads, and molecular weight distribution. Yes. This plastic is polyethylene made using a single site catalyst (paragraph 0009). In the examples of this publication, polyethylene produced using a single-site catalyst with a density of 0.918 g / cm ³ is used. Although there is no description of additives in this example, an antiblocking agent and an antistatic agent should be clearly added in view of the density. Also, this publication does not disclose the technical idea of preventing the transfer of the additive in the cell portion.
JP-A-11-170410 JP-A-9-123320

  Therefore, the object of the present invention is that even if additives such as a lubricant, an antiblocking agent, and an antistatic agent are excluded, it has performance such as a slippery property and an antiblocking property, and a cell mark is not attached to an object to be packed. Another object of the present invention is to provide a packing cushioning material having improved compression fracture resistance, puncture resistance, and the like.

That is, the packing cushioning material of the present invention is the packaging cushioning material having a plurality of sealed cells, in which the film layer is bonded to the cell layer on which a plurality of protrusions are formed, and the film layer and / or The cell layer is (A) 40 to 100% by mass of an ethylene (co) polymer that satisfies the following requirements (a) to (d), and (B) the density is 0.93 to 0.96 g / cm ³ . , 0-30 mass% linear low density polyethylene or high density polyethylene having a melt flow rate of 0.1 to 10 g / 10 min, and (C) high pressure having a melt flow rate of 0.1 to 10 g / 10 min. 0 to 30% by mass of a radical process ethylene polymer (the total of (A) component, (B) component and (C) component is 100% by mass), and the density is 0.93 to 0.96 g / cm ³ . Yes, melt flow rate 1-10g It consists of a resin composition that is / 10 minutes.
(A) Density 0.91 g / cm ^{3 to} 0.96 g / cm ³ ,
(B) Melt low rate 0.1 to 10 g / 10 min,
(C) molecular weight distribution (Mw / Mn) is 1.5 to 4.5,
(D) Difference between temperature T _{25 at} which 25% of the elution is obtained from the integral elution curve of the elution temperature-elution amount curve by continuous temperature rising elution fractionation method (TREF) and temperature T _{75 at} which 75% of the elution is eluted T ₇₅ -T ₂₅ and density d satisfy the relationship of the following (formula 1).
(Formula 1) T ₇₅ −T ₂₅ ≦ −670 × d + 644

Here, the resin composition comprises (A) 40 to 90% by mass of an ethylene (co) polymer, (B) 5 to 30% by mass of linear low-density polyethylene or high-density polyethylene, and (C) a high-pressure radical. It is desirable to contain 5 to 30% by mass of a method ethylene polymer (the total of (A) component, (B) component and (C) component is 100% by mass).
Moreover, the said resin composition may contain 700 ppm or less of antioxidant.
The antioxidant is preferably a natural antioxidant and a phosphorus antioxidant.
The antioxidant is vitamin E and a phosphorus antioxidant, and vitamin E is preferably 100 ppm or less in the resin composition, and the phosphorus antioxidant is preferably 600 ppm or less in the resin composition.
Moreover, it is desirable that the antioxidant contains tris (2,4-di-tert-butylphenyl) phosphite.

The (A) ethylene (co) polymer further has a temperature T at which 25% of the total amount obtained from the integral elution curve of the elution temperature-elution amount curve by (e) continuous temperature rising elution fractionation method (TREF) is eluted. the difference T ₇₅ -T ₂₅ and the density d of the temperature T _{75 to 25} and the total 75% elutes, it is preferable to satisfy the following relationship (equation 2).
(Formula 2) When d <0.950 g / cm ³ ,
T ₇₅ −T ₂₅ ≧ −300 × d + 285
When d ≧ 0.950 g / cm ³
T ₇₅ -T ₂₅ ≧ 0

The (A) ethylene (co) polymer further satisfies the following requirements (f) and (g): (A1) an ethylene (co) polymer, or the following requirements (h) and (i): (A2) It is desirable that it is an ethylene (co) polymer.
(F) The amount X (mass%) of the ODCB soluble component at 25 ° C., the density d, and the MFR satisfy the relationship of the following (formula 3) and (formula 4).
(Formula 3) When d−0.008log MFR ≧ 0.93,
X <2.0
(Formula 4) When d−0.008 log MFR <0.93,
X <9.8 × 10 ³ × (0.9300−d + 0.008logMFR) ² +2.0
(G) There are a plurality of peaks of the elution temperature-elution amount curve by the continuous temperature rising elution fractionation method (TREF).
(H) There is one peak of the elution temperature-elution amount curve by the continuous temperature rising elution fractionation method (TREF).
(I) It has one or more melting point peaks, and the highest melting point T _ml and density d satisfy the relationship of the following (formula 5).
(Formula 5) T _ml ≧ 150 × d-19

The (A2) ethylene (co) polymer preferably further satisfies the following requirement (j).
(J) Melt tension (MT) and melt flow rate (MFR) satisfy the following (formula 6).
(Formula 6) logMT ≦ −0.572 × logMFR + 0.3
The (A) ethylene (co) polymer (k) halogen concentration is preferably 10 ppm or less.
The (A) ethylene-based (co) polymer is preferably polymerized by a catalyst containing at least an organic cyclic compound having a conjugated double bond and a transition metal compound of Group 4 of the periodic table.

The packing cushioning material of the present invention is a packaging cushioning material having a plurality of sealed cells, in which a film layer is bonded to both surfaces of a cell layer on which a plurality of protrusions are formed. The layer is (A) 40 to 100% by mass of an ethylene (co) polymer that satisfies the requirements (a) to (d), and (B) the density is 0.93 to 0.96 g / cm ³ , 0-30 mass% linear low density polyethylene or high density polyethylene having a melt flow rate of 0.1-10 g / 10 min, and (C) a high pressure radical having a melt flow rate of 0.1-10 g / 10 min. Containing 0 to 30% by mass of a method ethylene polymer (total of component (A), component (B) and component (C) is 100% by mass), and the density is 0.93 to 0.96 g / cm ³ Melt flow rate is 1-10g / 10 It consists of the resin composition which is a part.

  The packing cushioning material of the present invention has performance such as lubricity and anti-blocking properties even if additives such as lubricants, anti-blocking agents, and antistatic agents are excluded, and marks of cells are attached to the packaged items. However, it is excellent in resistance to compression fracture and puncture.

[(A) Ethylene (co) polymer]
The (A) ethylene (co) polymer in the present invention is an ethylene homopolymer or ethylene-α-olefin copolymer that satisfies the following conditions (a) to (d).
(A) Density 0.91 g / cm ^{3 to} 0.96 g / cm ³ ,
(B) Melt low rate 0.1 to 10 g / 10 min,
(C) molecular weight distribution (Mw / Mn) is 1.5 to 4.5,
(D) Difference between temperature T _{25 at} which 25% of the elution is obtained from the integral elution curve of the elution temperature-elution amount curve by continuous temperature rising elution fractionation method (TREF) and temperature T _{75 at} which 75% of the elution is eluted T ₇₅ -T ₂₅ and density d satisfy the relationship of the following (formula 1).
(Formula 1) T ₇₅ −T ₂₅ ≦ −670 × d + 644

  (A) The ethylene (co) polymer is a homopolymer of ethylene or a copolymer obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms, preferably 3 to 12 carbon atoms. It is. Examples of the α-olefin having 3 to 20 carbon atoms include propylene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene and 1-dodecene. In addition, the total content of these α-olefins is usually 30 mol% or less, preferably 3 to 20 mol% or less.

(A) The density of (a) ethylene (co) polymer is in the range of 0.91 g / cm ^{3 to} 0.96 g / cm ³ , preferably 0.92 to 0.96 g / cm ³ , more preferably It is in the range of 0.93 to 0.95 g / cm ³ . When the density is less than 0.91 g / cm ³ , low molecular weight components increase, and there is a concern that transfer of the cell portion to the product or part that is the object to be packed occurs (cell marks are attached to the object to be packed). Moreover, there exists a possibility that a lubricity may be required because lubricity is inferior. On the other hand, when the density exceeds 0.96 g / cm ³ , the flexibility is lost, and there is a concern that the compression fracture strength and the like are reduced.

  (A) The ethylene (co) polymer (b) melt flow rate (hereinafter referred to as MFR) is in the range of 0.1 to 10 g / 10 minutes, preferably 0.5 to 8 g / 10 minutes, Preferably it is the range of 1.0-6 g / min. If the MFR is less than 0.1 g / 10 min, the moldability may be lowered. Moreover, when MFR exceeds 10 g / 10min, there exists a possibility that mechanical strength, such as impact resistance, tensile strength, tear strength, compression fracture strength, and puncture strength, may become inferior.

(A) The (c) molecular weight distribution (Mw / Mn) of the ethylene (co) polymer is preferably 1.5 to 4.5, more preferably 2.0 to 4.0, still more preferably 2.5 to The range is 3.0. If this molecular weight distribution is less than 1.5, the molding processability of the resin composition in the present invention may be inferior. If this molecular weight distribution exceeds 4.5, the tear strength, impact resistance, etc. may be insufficient.
(A) The molecular weight distribution (Mw / Mn) of the ethylene (co) polymer is determined by gel permeation chromatography (GPC) to obtain the mass average molecular weight (Mw) and the number average molecular weight, and the ratio (Mw / Mn). Can be obtained by calculating.

(A) The ethylene (co) polymer is obtained from an integral elution curve of an elution temperature-elution amount curve by (d) continuous temperature rising elution fractionation (TREF = Temperature Rising Elution Fractionation) as shown in FIG. Further, it is preferable that the difference T ₇₅ -T ₂₅ and the density d between the temperature T _{25 at} which 25% of the total is eluted and the temperature T _{75 at} which 75% of the total is eluted satisfy the relationship of the following (formula 1).
(Formula 1) T ₇₅ −T ₂₅ ≦ −670 × d + 644
When T ₇₅ -T ₂₅ and the density d do not satisfy the relationship of the above (Formula 1), there is a concern that the cell mark may be attached to the package.

The measuring method of 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 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, ODCB is allowed to flow through the column at a constant flow rate, and the sample is sequentially eluted while raising the column temperature at a constant rate of 50 ° C./hr. At this time, the concentration of the sample eluted in the solvent is continuously detected by measuring the absorption with respect to the wave number of 2925 cm ⁻¹ of the asymmetric stretching vibration of methylene with 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, since a change in elution rate with respect to a temperature change can be continuously analyzed with a very small amount of sample, it is possible to detect a relatively fine peak that cannot be detected by a fractionation method.

In addition, (A) the ethylene (co) polymer further has a temperature T at which 25% of the total obtained from the integral elution curve of the elution temperature-elution amount curve by (e) continuous temperature rising elution fractionation method (TREF) is eluted. the difference T ₇₅ -T ₂₅ and the density d of the temperature T _{75 to 25} and the total 75% elutes, it is preferable to satisfy the following relationship (equation 2).
(Formula 2) When d <0.950 g / cm ³
T ₇₅ −T ₂₅ ≧ −300 × d + 285
When d ≧ 0.950 g / cm ³
T ₇₅ -T ₂₅ ≧ 0
When T ₇₅ -T ₂₅ and the density d do not satisfy the relationship of the above (Formula 2), there is a possibility that the cell mark is attached to the packaged item.

  (A) The ethylene (co) polymer further satisfies the requirements of (f) and (g) described later. (A1) The ethylene (co) polymer, or the requirements of (h) and (i) described later. (A2) It is preferable that it is either ethylene (co) polymer.

(A1) The amount (% by mass) of the ODCB soluble content at 25 ° C. and the density d and MFR of the ethylene (co) polymer satisfy the relationship of the following (formula 3) and (formula 4): And
(Formula 3) When d−0.008log MFR ≧ 0.93,
X <2.0
(Formula 4) When d−0.008 log MFR <0.93,
X <9.8 × 10 ³ × (0.9300−d + 0.008logMFR) ² +2.0
Preferably,
If d−0.008log MFR ≧ 0.93,
X <1.0
d-0.008 log MFR <0.93,
X <7.4 × 10 ³ × (0.9300−d + 0.008 log MFR) ² +2.0
And more preferably,
If d−0.008log MFR ≧ 0.93,
X <0.5
d-0.008 log MFR <0.93,
X <5.6 × 10 ³ × (0.9300−d + 0.008 log MFR) ² +2.0
Satisfied with the relationship.

Here, the amount X of soluble ODCB at 25 ° C. is measured by the following method. A sample of 0.5 g is heated with 20 ml of ODCB at 135 ° C. for 2 hours to completely dissolve the sample, and then cooled to 25 ° C. This solution is allowed to stand at 25 ° C. overnight, and then filtered through a Teflon (registered trademark) filter to collect the filtrate. The intensity of the absorption peak in the vicinity of a wave number of 2925 cm ⁻¹ corresponding to the asymmetric stretching vibration of methylene is measured for this filtrate, which is a sample solution, using an infrared spectrometer, and the sample concentration is calculated using a calibration curve prepared in advance. From this value, the amount of soluble ODCB at 25 ° C. is obtained.

  The ODCB soluble content at 25 ° C. is a highly branched component and a low molecular weight component contained in the (A) ethylene (co) polymer, causing a decrease in heat resistance and stickiness of the surface of the molded product. In addition, it is desirable that the content is small because it causes blocking of the inner surface of the molded body. The amount of ODCB solubles is affected by (A) the content and molecular weight of the α-olefin in the entire ethylene (co) polymer, that is, density and MFR. Therefore, the fact that the density and the amount of soluble matter of MFR and ODCB satisfy the above relationship is that (A) when the ethylene (co) polymer is a copolymer, α contained in the whole copolymer -Indicates that there is little uneven distribution of olefins.

  The (A1) ethylene (co) polymer has a plurality of peaks in the elution temperature-elution amount curve obtained by (g) continuous temperature rising elution fractionation method (TREF). Of the plurality of peaks, the peak temperature on the high temperature side is particularly preferably 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.

  Here, as shown in FIG. 2, (A1) ethylene (co) polymer has a special peak having substantially a plurality of peaks in the elution temperature-elution amount curve obtained by the continuous temperature rising elution fractionation method (TREF). Ethylene (co) polymer. On the other hand, the ethylene (co) polymer of FIG. 3 is an ethylene (co) polymer having substantially one peak in the elution temperature-elution amount curve obtained by the continuous temperature rising elution fractionation method (TREF). This is a typical metallocene-based ethylene (co) polymer.

As shown in FIG. 4, the (A2) ethylene (co) polymer in the present invention has one peak in the elution temperature-elution amount curve by (h) continuous temperature rising elution fractionation method (TREF).
The (A2) ethylene (co) polymer having one peak of the elution temperature-elution amount curve by TREF is excellent in heat resistance.

In addition, the (A2) ethylene (co) polymer in the present invention has (i) one or more melting point peaks, and the highest melting point T _ml and density d among them have the relationship of the following (formula 5). Satisfied.
(Formula 5) T _ml ≧ 150 × d-19
If the melting point T _m1 and the density d do not satisfy the relationship of the above (Formula 5), the heat resistance may be inferior.

Among the (A2) ethylene (co) polymers, ethylene (co) polymers that satisfy the following requirement (j) are preferable.
(J) Melt tension (MT) and melt flow rate (MFR) satisfy the relationship of the following (formula 6) (formula 6) logMT ≦ −0.572 × logMFR + 0.3
When MT and MFR satisfy the relationship of the above (formula 6), moldability such as film molding becomes good.

  Here, the (A2) ethylene (co) polymer has one TREF peak as shown in FIG. 4, but the ethylene (co) polymer by a conventional typical metallocene catalyst is the above (formula This does not satisfy 2) and is distinguished from the ethylene (co) polymer by the typical metallocene catalyst.

  The catalyst used for producing the (A) ethylene (co) polymer is not particularly limited, but the (A) ethylene (co) polymer is preferably obtained by polymerizing ethylene alone in the presence of a single site catalyst. It is desirable to be a linear ethylene (co) polymer obtained by copolymerization or obtained by copolymerizing ethylene and an α-olefin. Such a linear ethylene (co) polymer has a relatively narrow molecular weight distribution and composition distribution, so it has excellent mechanical properties such as resistance to compression fracture and puncture, and heat sealability and heat resistance blocking. Further, it is possible to provide a cushioning material that is excellent in properties and the like, has few low molecular weight components, and does not have cell marks on the package.

As the single-site catalyst, in addition to the conventional typical metallocene catalyst, CGC catalyst, etc., a catalyst containing at least an organic cyclic compound having a conjugated double bond and a transition metal compound of Group 4 of the periodic table, particularly A catalyst obtained by mixing the compounds a1 to a4 is desirable.
a1: formula ^{_{Me 1 R 1 p R 2 q}} (OR 3) r X 1 compound represented by the _4-pqr (wherein Me ¹ represents zirconium, titanium, hafnium, R ¹ and R ³ are carbon atoms 1 to 24 hydrocarbon groups, R ² represents 2,4-pentanedionato ligand or derivative thereof, benzoylmethanato ligand, benzoylacetonate ligand or derivative thereof, X ¹ represents a halogen atom , 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: Compound represented by the general formula Me ² R ⁴ _m (OR ⁵ ) _n X ² _zmn (wherein Me ² is a group element of the periodic table 1, ^2, 12, 13 and R ⁴ and R ⁵ are each a carbon number) 1 to 24 hydrocarbon groups, X ² represents a halogen atom or a hydrogen atom (however, when X ² is a hydrogen atom, Me ² is limited to a group 13 element in the periodic table), and z is a valence of Me ² M and n are integers satisfying the ranges of 0 ≦ m ≦ z and 0 ≦ n ≦ z, respectively, and 0 ≦ m + n ≦ z).
a3: An organic cyclic compound having a conjugated double bond.
a4: Modified organoaluminum oxy compound and / or boron compound containing Al—O—Al bond.

Further details will be described below.
Of general formula ^{_{Me 1 R 1 p R 2 q}} (OR 3) r X 1 compound represented by the _4-pqr of the catalyst component a1, Me ¹ represents zirconium, titanium, hafnium, these transition metals The type is not limited, and a plurality of types can be used, but it is particularly preferable that zirconium having excellent weather resistance of the copolymer is included. R ¹ and R ³ are each 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 aryl groups such as benzyl group, trityl group, phenethyl group, styryl group, benzhydryl group, phenylbutyl group, and neofoyl group. These may be branched. R ² represents a 2,4-pentanedionate ligand or a derivative thereof, a benzoylmethanato ligand, a benzoylacetonato ligand or a derivative thereof. X ¹ represents a halogen atom such as fluorine, iodine, chlorine and bromine. 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.

Examples of the compound represented by the general formula of the catalyst component a1 include tetramethylzirconium, tetraethylzirconium, tetrabenzylzirconium, tetrapropoxyzirconium, tripropoxymonochlorozirconium, tetraethoxyzirconium, tetrabutoxyzirconium, tetrabutoxytitanium, tetrabutoxy Hafnium and the like are mentioned, and Zr (OR) ₄ compounds such as tetrapropoxyzirconium and tetrabutoxyzirconium are particularly preferred, and two or more of these may be used in combination. Specific examples of the 2,4-pentanedionato ligand or derivative thereof, benzoylmethanato ligand, benzoylacetonate ligand or derivative thereof include tetra (2,4-pentandionato) zirconium. , Tri (2,4-pentanedionato) chloride zirconium, di (2,4-pentandionato) dichloride zirconium, (2,4-pentandionato) trichloride zirconium, di (2,4-pentandionato) Diethoxide zirconium, di (2,4-pentanedionato) di-n-propoxide zirconium, di (2,4-pentandionato) di-n-butoxide zirconium, di (2,4-pentane) Diato) dibenzylzirconium, di (2,4-pentanedionate) dineoyl zirconium, tetra ( Benzoylmethanato) zirconium, di (dibenzoylmethanato) diethoxide zirconium, di (dibenzoylmethanato) di-n-propoxide zirconium, di (dibenzoylmethanato) di-n-butoxidezirconium, di (benzoyl) Acetonato) diethoxide zirconium, di (benzoylacetonato) di-n-propoxide zirconium, di (benzoylacetonato) di-n-butoxide zirconium and the like.

Said wherein Me ² in the general formula _{^{Me 2 R 4 m (OR 5}} ) n X 2 compound represented by _zmn catalyst component a2 shows the periodic table 1,2,12,13 group element, lithium, sodium, Potassium, magnesium, calcium, zinc, boron, aluminum and the like. R ⁴ and R ⁵ are each a hydrocarbon group having 1 to 24 carbon atoms, preferably 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, specifically a methyl group, an ethyl group, a propyl group, an isopropyl group, Alkyl group such as butyl group; alkenyl group such as vinyl group and allyl group; aryl group such as phenyl group, tolyl group, xylyl group, mesityl group, indenyl group and naphthyl group; benzyl group, trityl group, phenethyl group and styryl group Aralkyl groups such as a benzhydryl group, a phenylbutyl group, and a neofoyl group. These may be branched. X ² represents a halogen atom or hydrogen atom such as fluorine, iodine, chlorine and bromine. However, when X ² is a hydrogen atom, Me ² is limited to a group 13 element of the periodic table exemplified by boron, aluminum and the like. Z represents the valence of Me ² , and m and n are integers satisfying the ranges of 0 ≦ m ≦ z and 0 ≦ n ≦ z, respectively, and 0 ≦ m + n ≦ z.

  Examples of the compound represented by the general formula of the catalyst component a2 include organolithium compounds such as methyllithium, ethyllithium and butyllithium; organomagnesium compounds such as dimethylmagnesium, diethylmagnesium, methylmagnesium chloride and ethylmagnesium chloride; dimethyl Organic zinc compounds such as zinc and diethylzinc; Organic boron compounds such as trimethylboron and triethylboron; Trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, trihexylaluminum, tridecylaluminum, diethylaluminum chloride, ethylaluminum dichloride , Ethylaluminum sesquichloride, diethylaluminum ethoxide, diethylaluminum Derivatives of organoaluminum compounds such as beam hydride diisobutylaluminum hydride and the like.

  The organic cyclic compound having a conjugated double bond of the catalyst component a3 is cyclic, having one or more rings having 2 or more, preferably 2 to 4, more preferably 2 to 3 conjugated double bonds. A cyclic hydrocarbon compound having 4 to 24 carbon atoms, preferably 4 to 12 carbon atoms; the cyclic hydrocarbon compound is partially a hydrocarbon residue having 1 to 6 carbon atoms (typically having 1 to A cyclic hydrocarbon compound substituted with 12 alkyl groups or an aralkyl group; having 1 or 2 rings having 2 or more, preferably 2 to 4, more preferably 2 to 3 conjugated double bonds An organosilicon compound having a cyclic hydrocarbon group having a total carbon number of 4 to 24, preferably 4 to 20; the cyclic hydrocarbon group is partially a hydrocarbon residue or alkali metal salt (sodium 1-6) Or lithium salt) The organosilicon compound is contained. Particularly preferred is one having a cyclopentadiene structure in any of the molecules.

  Suitable examples of the compound include cyclopentadiene, indene, azulene, or alkyl, aryl, aralkyl, alkoxy or aryloxy derivatives thereof. Moreover, the compound which these compounds couple | bonded (bridge | crosslinked) via the alkylene group (The carbon number is 2-8 normally, Preferably 2-3) is also used suitably.

The organosilicon compound having a cyclic hydrocarbon group can be represented by the following general formula.
A _L SiR _4-L
Here, A represents the cyclic hydrogen group exemplified by cyclopentadienyl group, substituted cyclopentadienyl group, indenyl group, and substituted indenyl group, and R represents methyl group, ethyl group, propyl group, isopropyl group, butyl group An alkyl group such as a group; an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, or 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; To 24, preferably 1 to 12 hydrocarbon residues or hydrogen, L is 1 ≦ L ≦ 4, preferably 1 ≦ L ≦ 3.

Specific examples of the organic cyclic hydrocarbon compound of component a3 include cyclopentadiene, methylcyclopentadiene, ethylcyclopentadiene, propylcyclopentadiene, butylcyclopentadiene, 1,3-dimethylcyclopentadiene, 1-methyl-3-ethylcyclopentadiene. 1-methyl-3-propylcyclopentadiene, 1-methyl-3-butylcyclopentadiene, 1,2,4-trimethylcyclopentadiene, pentamethylcyclopentadiene, indene, 4-methyl-1-indene, 4,7- Cyclopolyene having 5 to 24 carbon atoms such as dimethylindene, cycloheptatriene, methylcycloheptatriene, cyclooctatetraene, azulene, fluorene, methylfluorene, 1H-cyclopenta [l] phenanthrene Or substituted cyclopolyenes, monocyclopentadienyl silane, biscyclopentadienyl silane, tris cyclopentadienyl silane, mono indenyl silane, bis indenyl silane, and tris indenyl silane.
These compounds serving as ligands may be used alone or in combination. A plurality of complexes or catalysts having these as ligands may be combined.

  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 referred to as an aluminoxane. Usually, it contains 1 to 100, preferably 1 to 50 Al—O—Al bonds. The modified organoaluminum oxy compound may be linear or cyclic.

The reaction between organoaluminum and water is usually carried out 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 0.25 / 1 to 1.2 / 1, preferably 0.5 / 1 to 1/1.

As the boron compound, borate or borane is used. Specific examples of the borate include tributylammonium tetra (o-fluorophenyl) borate, tributylammonium tetra (p-fluorophenyl) borate, tributylammonium tetra (m-fluorophenyl) borate, tributylammonium tetra (3,5-difluorophenyl). ) Borate, tributylammonium tetra (pentafluorophenyl) borate, dimethylanilinium tetra (o-fluorophenyl) borate, dimethylanilinium tetra (p-fluorophenyl) borate, dimethylanilinium tetra (m-fluorophenyl) borate, dimethyl Anilinium tetra (3,5-difluorophenyl) borate, dimethylanilinium tetra (pentafluorophenyl) borate, trityltetra ( -Fluorophenyl) borate, trityltetra (p-fluorophenyl) borate, trityltetra (m-fluorophenyl) borate, trityltetra (pentafluorophenyl) borate, tropiniumtetra (o-fluorophenyl) borate, tropiniumtetra ( Examples thereof include p-fluorophenyl) borate, tropinium tetra (m-fluorophenyl) borate, tropinium tetra (3,5-difluorophenyl) borate, and tropinium tetra (pentafluorophenyl) borate. Preferable examples include tributylammonium tetra (pentafluorophenyl) borate, dimethylanilinium tetra (pentafluorophenyl) borate, trityltetra (pentafluorophenyl) borate, and tropinium tetra (pentafluorophenyl) borate.
Specific examples of the borane compound include tri (o-fluorophenyl) borane, tri (p-fluorophenyl) borane, tri (m-fluorophenyl) borane, tri (3,5-difluorophenyl) borane, tri ( Pentafluorophenyl) borane, preferably tri (pentafluorophenyl) borane.

The catalyst may be used by mixing and contacting a1 to a4, but it is preferable to use the catalyst supported on an inorganic carrier and / or a particulate polymer carrier (a5).
Examples of the inorganic carrier and / or particulate polymer carrier (a5) include carbonaceous materials, metals, metal oxides, metal chlorides, metal carbonates or mixtures thereof, thermoplastic resins, thermosetting resins, and the like.
Preferred as the inorganic carrier is a metal oxide (single oxide or double oxide).
Specific examples include SiO ₂ , Al ₂ O ₃ , MgO, ZrO ₂ , TiO ₂ , B ₂ O ₃ , CaO, ZnO, BaO, ThO _2, or a mixture thereof, and SiO ₂ —Al ₂ O _3. , SiO ₂ —V ₂ O ₅ , SiO ₂ —TiO ₂ , SiO ₂ —MgO, SiO ₂ —Cr ₂ O _{3 and the} like. Among these, those containing as a main component at least one component selected from the group consisting of SiO ₂ and Al ₂ O ₃ are preferable.
As the organic compound, any of a thermoplastic resin and a thermosetting resin can be used. Specifically, particulate polyolefin, polyester, polyamide, polyvinyl chloride, poly (meth) acrylate, polystyrene, Examples include norbornene, various natural polymers, and mixtures thereof.

  The inorganic carrier and / or the particulate polymer carrier can be used as they are, but preferably, as a pretreatment, these carriers are contacted with an organoaluminum compound or a modified organoaluminum compound containing an Al—O—Al bond. After that, it can also be used as component a5.

  (A) A method for producing an ethylene (co) polymer is produced by a gas phase polymerization method, a slurry polymerization method, a solution polymerization method, or the like that is substantially free of a solvent in the presence of the catalyst. In the state where the above are excluded, aliphatic hydrocarbons such as butane, pentane, hexane and heptane, aromatic hydrocarbons such as benzene, toluene and xylene, and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane are exemplified. Produced in the presence or absence of an active hydrocarbon 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 7 MPaG in the low to medium pressure method, preferably The pressure is from normal pressure to 2 MPaG, and usually 150 MPaG or less in the high pressure method. The polymerization time is usually from 3 minutes to 10 hours, preferably from about 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 about 2 minutes to 20 minutes. In addition, the polymerization is not particularly limited to a one-stage polymerization method, but also a two-stage or more multi-stage polymerization method in which polymerization conditions such as hydrogen concentration, monomer concentration, polymerization pressure, polymerization temperature, and catalyst are different from each other. A particularly preferable production method includes the method described in JP-A-5-132518.

(A) The ethylene (co) polymer is a halogen concentration of at most 10 ppm, preferably 5 ppm or less, more preferably substantially, by using a catalyst having no halogen such as chlorine among the above catalyst components. 2 ppm or less (ND: Non-Detect) which is not included in.
By using such a halogen-free ethylene (co) polymer such as chlorine, there is no need to use an acid neutralizer (halogen absorber) as in the past, and chemical stability is excellent and clean packaging. A cushioning material can be provided.

[(B) linear low density polyethylene or high density polyethylene]
The (B) linear low density polyethylene or high density polyethylene of the present invention is a linear chain produced with a Ziegler catalyst, a Philips catalyst, a metallocene catalyst, etc. excluding the (A) ethylene (co) polymer. Low density polyethylene and high density polyethylene. The density of (B) a linear low density polyethylene or high density polyethylene is a 0.93~0.96g / cm ^3, preferably 0.94~0.96g / cm ^3, more preferably, 0.94 It is in the range of ˜0.95 g / cm ³ . (B) Linear low-density polyethylene or high-density polyethylene is not essential, but for example, by blending high-density polyethylene, sufficient rigidity (strength of waist) is easily given to the packing cushioning material of the present invention. It becomes possible.

  (B) The MFR of the linear low-density polyethylene or high-density polyethylene is 0.1 to 10 g / 10 minutes, preferably 1.0 to 8 g / 10 minutes, more preferably 1.5 to 6 g / 10 minutes. . When the MFR is less than 0.1 g / 10 min, the effect of improving the molding processability of the resin composition in the present invention is diminished, and when the MFR exceeds 10 g / 10 min, the impact resistance and tensile strength of the resin composition in the present invention are reduced. There is a possibility that the effect of improving mechanical strength such as tear strength, compressive fracture strength, and puncture strength cannot be expected.

[(C) High-pressure radical method ethylene polymer]
The (C) high-pressure radical method ethylene polymer in the present invention is an ethylene polymer obtained by a high-pressure radical method. (C) The MFR of the high pressure radical process ethylene polymer is 0.1 to 10 g / 10 min. (C) If the MFR of the high-pressure radical method ethylene polymer is less than 0.1 g / 10 min, there is a possibility that the moldability will be reduced, and if it exceeds 10 g / 10 min, impact resistance, tensile strength, tear strength, There is a risk that the compressive fracture strength, the puncture strength, and the like are reduced.
(C) High pressure radical ethylene polymer includes (C1) low density polyethylene, (C2) ethylene-vinyl ester copolymer, (C3) copolymer of ethylene and α, β-unsaturated carboxylic acid or its derivative. Examples include coalescence.

[(C1) low density polyethylene]
(C1) The MFR of the low density polyethylene is 0.1 to 10 g / 10 minutes, preferably 0.5 to 8 g / 10 minutes, more preferably 1.0 to 6 g / 10 minutes. If it is this range, melt tension will become an appropriate range and a moldability will improve. The density of the (C1) low density polyethylene is in the range of 0.91~0.94g / cm ^3, preferably 0.910 to 0.935 g / cm ^3, more preferably 0.920~0.930g / Cm ³ range.
(C1) Molding processability is improved by blending low density polyethylene. (C1) The melt tension of the low density polyethylene is preferably 1.5 to 25 g, more preferably 3 to 20 g, and still more preferably 3 to 15 g. The molecular weight distribution Mw / Mn of (C1) low density polyethylene is preferably 3.0 to 12, more preferably 4.0 to 8.0.

[(C2) ethylene-vinyl ester copolymer]
(C2) The ethylene-vinyl ester copolymer is produced by a high-pressure radical polymerization method and contains ethylene as a main component. Ethylene, vinyl propionate, vinyl acetate, vinyl caproate, vinyl caprylate, It is a copolymer with vinyl ester monomers such as vinyl laurate, vinyl stearate, and vinyl trifluoroacetate. Among these, an ethylene-vinyl acetate copolymer is particularly preferable. Further, a copolymer composed of 50 to 99.5% by mass of ethylene, 0.5 to 50% by mass of vinyl ester, and 0 to 49.5% by mass of other copolymerizable unsaturated monomers is preferable. In particular, the vinyl ester content is preferably in the range of 3 to 30% by mass, more preferably 5 to 25% by mass.

[(C3) Copolymer of ethylene and α, β-unsaturated carboxylic acid or derivative thereof]
(C3) As a copolymer of ethylene and an α, β-unsaturated carboxylic acid or a derivative thereof, ethylene- (meth) acrylic acid or an alkyl ester copolymer thereof may be mentioned. , Methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butyl methacrylate, acrylic acid Examples include cyclohexyl, cyclohexyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, glycidyl acrylate, glycidyl methacrylate, and the like. Of these, particularly preferred are alkyl (meth) acrylates such as methyl (meth) acrylate and ethyl (meth) acrylate. Further, the content of the (meth) acrylic acid ester is preferably 3 to 30% by mass, more preferably 5 to 25% by mass.

(Resin composition)
The resin composition in the present invention includes (A) an ethylene (co) polymer (hereinafter also referred to as (A) component), (B) a linear low density polyethylene or high density polyethylene (hereinafter also referred to as (B) component). ) And (C) high-pressure radical ethylene polymer (hereinafter also referred to as component (C)), and preferably contains no slip agent, anti-blocking agent, or antistatic agent, and essentially contains (A ) Component, (B) component and (C) component.
Such a resin composition is a mixture of (A) ethylene (co) polymer, HDPE (or LLDPE) and high-pressure low-density polyethylene (LDPE), where LDPE is easy moldability and HDPE is the strength of the sheet. (A) The ethylene (co) polymer contributes to the compatibility of HDPE and LDPE.

The ratio of each component in the resin composition is (A) component 40 to 100% by mass, (B) component 0 to 30% by mass, and (C) component 0 to 30% by mass ((A) component, (B). The total of the component and the component (C) is 100% by mass).
When the component (A) is less than 40% by mass (when the sum of the component (B) and the component (C) exceeds 60% by mass), impact resistance, tensile strength, tear strength, compression fracture strength, puncture strength, etc. There is a risk that the mechanical strength is inferior.

  The proportion of each component in the resin composition is preferably (A) component 40 to 90% by mass, (B) component 5 to 30% by mass, and (C) component 5 to 30% by mass, more preferably (A). 50 to 80% by mass of component, 5 to 25% by mass of (B) component, and 5 to 25% by mass of component (C) (total of (A) component, (B) component and (C) component is 100% by mass) .

The density of the resin composition is ^{0.93g / cm 3 ~0.96g / cm 3} , is preferably 0.935 g / cm ³ or higher, more preferably at 0.94~0.955g / cm ³ More preferably, it is 0.94 to 0.95 g / cm ³ .
If the density of the resin composition is less than 0.93 g / cm ^3, it is necessary to add a slip agent, an anti-blocking agent, and an antistatic agent, and low molecular weight components increase, so that cell traces may adhere to the packaged item. Arise. Further, if the density of the resin composition exceeds 0.96 g / cm ³ , the cushioning material for packing lacks flexibility, and there is a risk that the impact resistance, compressive fracture strength, puncture strength, etc. will be inferior. .

Moreover, MFR of a resin composition is 1-10 g / 10min, Preferably it is 2-8g / 10min, More preferably, it is the range of 2-6g / 10min.
When the MFR of the resin composition is less than 1 g / 10 minutes, the resin discharge amount at the time of molding is lowered, and the moldability is lowered. Moreover, when MFR of a resin composition exceeds 10 g / 10min, there exists a possibility that the drawdown at the time of shaping | molding may deteriorate.
The oxygen induction period of the resin composition is desirably 3 minutes or longer, preferably 3 to 12 minutes, and more preferably 4 to 11 minutes. If the oxygen induction period is less than 3 minutes, the resin may be deteriorated. Moreover, when the oxygen induction period exceeds 12 minutes, it is necessary to add a large amount of an antioxidant and transfer may occur.

  As a preparation method of the resin composition in the present invention, each component is mixed by various known methods such as a Henschel mixer, a V blender, a ribbon blender, a tumbler mixer or the like, or after mixing, a single screw extruder, a twin screw extruder Examples thereof include a method of granulation or pulverization after melt-kneading with a machine, kneader, Banbury mixer or the like.

〔Antioxidant〕
The resin composition in the present invention does not contain commonly used additives such as slip agents, antiblocking agents, and antistatic agents, but must be molded under severe molding conditions such as a high molding temperature. If not obtained, an antioxidant up to 700 ppm or less can be added to the resin composition.
When antioxidant exceeds 700 ppm in a resin composition, there exists a possibility that a cell trace may adhere to to-be-packaged goods, such as a product and components.
Examples of antioxidants include phenolic antioxidants, phosphorus antioxidants, natural antioxidants, and the like.

  Examples of phenolic antioxidants include 2,6-di-t-butyl-4-methylphenol, tocopherol, 4-hydroxymethyl-2,6-di-t-butylphenol, and 2,6-di-t-. Butyl-4-ethylphenol, 2,6-di-t-butyl-4-methoxyphenol, octadecyl-3- (4′-hydroxy-3 ′, 5′-di-t-butylphenyl) propionate, 2,2 '-Methylenebis (4-methyl-6-t-butylphenol), 2,2'-oxamidobis [ethyl 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,2'-ethylidene Bis (4,6-di-t-butylphenol), 2,2'-methylenebis (4-ethyl-6-t-butylphenol), 4,4'-methylenebis (2,6 Di-t-butylphenol), 4,4'-butylidenebis (2-t-butyl-5-methylphenol), 4,4'-thiobis (3-methyl-6-t-butylphenol), N, N'-hexa Methylenebis (3,5-di-t-butyl-4-hydroxyhydrocinnamate), hexamethylenebis (3,5-di-t-butyl-4-hydroxyhydrocinnamate, 1,1,3-tris ( 2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, Pentaerythritol tetrakis- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (also known as tetrakis [methylene-3- (3 ′, 5′-di) t-butyl-4′-hydroxyphenyl) propionate] methane), bis [3,3-bis (4′-hydroxy-3′-t-butylphenyl) butanoic acid] glycol ester, 1,4-benzenedicarboxylic acid bis [2- (1,1-dimethylethyl) -6-[[3- (1,1- (dimethylethyl) -2-hydroxy-5-methylphenyl] methyl] -4-methylphenyl] ester, tris (3 , 5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, 2- [1- (2-Hydroxy-3,5-di-t-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate, 2-t-butyl-6- (3′-t- Butyl-5′-methyl-2′-hydroxybenzyl) -4-methylphenyl acrylate, 3,9-bis [2- {3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane and the like.

Examples of phosphorus antioxidants include 3,5-di-tert-butyl-4-hydroxybenzyl phosphite diethyl ester and bis (2,6-di-tert-butyl-4-methylphenoxy) diphosphospiro. Undecane, bis (stearyl) diphosphospiroundecane, cyclic netopentanetetraylbis (nonylphenylphosphite), bis (nonylphenylphenoxy) diphosphospiroundecane, 3,4,5,6-dibenzo-1,2 -Oxaphosphan-2-oxide, tris (2,4-di-t-butylphenyl) phosphite, 2,4,6-tri-t-butylphenyl-2-butyl-2-ethyl-1,3- Propanediol phosphite, 2,2′-methylenebis (4,6-di-t-butylphenyl) octyl phosphite, bis [ 2,4-bis (1,1-dimethylethyl) -6-methyl-phenyl] ethyl phosphite, bis (2,4-di-t-butylphenoxy) diphosphospirodecane, trilauryl trithiophosphite, 1 , 1,3-Tris (2-methyl-4-di-tridecyl phosphite 5-t-butylphenyl) butane, 2,2′-ethylidenebis (4,6-di-t-butylphenyl) fluorophosphite 4,4′-isopropylidene diphenol alkyl (C12-C15) phosphite, 4,4′-butylidenebis (3-methyl-6-tert-butylphenyl) -di-tridecyl phosphite, diphenylisodecyl phosphite , Diphenyl mono (tridecyl) phosphite, tris- (mono & di-mixed nonylphenyl) phosphite, phenyl-bi Phenol A pentaerythritol diphosphite, di (laurylthio) pentaerythritol diphosphite, tetrakis (2,6-di-t-butyl-4-n-octadecyloxycarbonylethyl-phenyl) -4,4'-biphenylene-di Phosphonite, tetrakis [2,6-di-tert-butyl-4- (2,4′-di-tert-butylphenyloxycarbonyl) -phenyl] -4,4′-biphenylene-diphosphonite), Tricetyl trithiophosphite, condensate of di-t-butylphenyl-m-cresyl phosphonite and biphenyl, tetrakis (2,4-di-t-butylphenyl) -4,4′-biphenylene diphospho Knight, cyclic butylethylpropanediol-2,4,6-tri-butylphenylphosphine Iit, tris- [2- (2,4,8,10-tetrabutyl-5,7-dioxa-6-phospho-dibenzo- {a, c} cyclohepten-6-yloxy) ethyl] amine, bis (3,5 -Ethyl di-t-butyl-4-hydroxybenzylphosphonate) calcium, 3,9-bis {2,4-bis (1-methyl-1-phenylethyl) phenoxy} -2,4,8,10-tetraoxa -3,9-diphosphaspiro [5,5] undecane and the like.
Among these phosphorus-based antioxidants, tris (2,4-di-tert-butylphenyl) phosphite is preferable in that it has a good antioxidant effect when incorporated in a small amount and has little bleed-out to the surface. .

  Natural antioxidants originally include those extracted from compounds existing in natural products, or synthetic products corresponding to these natural products. Examples of natural antioxidants include tocopherols (vitamin E) such as α-, β-, γ-, δ-tocopherol and dimers thereof; vitamin B such as B1, B2, and B6 Groups and their derivatives; vitamin K groups such as K1 to K7 and their derivatives. Among these, vitamins such as vitamin E and K are particularly preferable from the viewpoint of suppressing oxidative deterioration and high thermal stability, and vitamin E is particularly preferable.

The antioxidant is not particularly limited, but a combination of a natural antioxidant and a phosphorus antioxidant is preferable in consideration of the effect of preventing cell transfer traces, the antioxidant effect, and the economic effect. In particular, a combination of vitamin E and a phosphorus antioxidant is preferable.
Here, vitamin E is preferably 100 ppm or less in the resin composition, and the phosphorus antioxidant is preferably 600 ppm or less in the resin composition.
In the above blending amount, it is better not to have an antioxidant when considering the transfer prevention effect. On the other hand, in consideration of thermal stability and transfer, only a maximum of 600 ppm of the phosphorus-based antioxidant can be added. If it is added more, the possibility of transfer increases. Therefore, in order to further improve the thermal stability, it is possible to satisfy both the transfer effect and the thermal stability by adding up to 100 ppm of vitamin E, which is highly effective in a small amount.
Therefore, even if it is only expensive vitamin E, transcription | transfer generate | occur | produces and the compounding ratio of this invention was determined in consideration of the transcription | transfer effect, thermal stability, and economical efficiency.

[Packing cushioning material]
The packing cushioning material of the present invention is not limited in its shape and the like, for example, as shown in FIG. This packing cushioning material 10 is a circular bag-like protrusion, and a plurality of cells (air chambers) 16, 16,... With air sealed inside are formed on the surface. The shape of the air chamber may be a cylindrical shape, a polygonal prism shape such as a triangular prism or a quadrangular prism, a cone, a polygonal pyramid shape such as a triangular pyramid or a quadrangular pyramid, a truncated cone, a polygonal frustum shape, or a combination thereof.
Usually, the height of the cell (air chamber) is 1 to 20 mm, the bottom area is 0.5 to 15 cm ² , and the interval between the air chambers is 0.5 to 100 mm.

  As shown in FIG. 6, the packing cushioning material 10 is formed by laminating a flat base film 12 (film layer) and an embossed film 14 (cell layer) on which a plurality of protrusions are formed. . The manufacturing method of this packing material 10 for packing is not specifically limited, It can manufacture by a conventionally well-known method. For example, methods described in Japanese Patent Publication No. 37-13782, Japanese Patent Publication No. 38-330, Japanese Patent Application Laid-Open No. 9-123320, and the like can be applied.

FIG. 7 shows another example of the cushioning material for packing according to the present invention. This packing cushioning material 20 has an embossed film 22 (cell layer) formed with a plurality of protrusions as an intermediate layer. It has a three-layer structure in which flat films 24 and 26 (film layers) are bonded to both surfaces.
Thus, the packing cushioning material is composed of a laminated film of two layers or three or more layers. Each layer may be made of the same material, or layers made of different materials may be combined. When combining layers made of different materials, it is necessary to make a combination that increases the laminate strength.

The air chamber sheet which is the cushioning material for packing according to the present invention is a layer in which at least one of the inner and outer layers or all the layers are made of the above-described resin composition. When using the resin composition in this invention for a one part layer, the resin composition in this invention is used for the layer which contacts a packaged object. A small amount of an anti-blocking agent or the like may be added to the layer that does not come into contact with the package.
Usually, the thickness of each layer is 10-100 micrometers, More preferably, it is 20-50 micrometers.

  The cushioning material for packing (air chamber sheet) manufactured using the resin composition of the present invention has a compressive fracture strength of cells (air chamber) of 300 kg / piece or more, a waist strength of 10 to 50 g by a handle ohmmeter, oxygen It is excellent in that the induction time can be 10 minutes or more.

EXAMPLES Next, although an Example demonstrates this invention in more detail, this invention is not limited by these.
The measuring method of the physical property in a present Example is as follows.

[density]
Conforms to JIS K6962-2.
[MFR]
Conforms to JIS K6962-2.
[Mw / Mn]
It measured using GPC (Waters 150C type | mold). ODCB at 135 ° C. was used as the solvent. The column used was Shodex HT806M.

[TREF]
First, a sample was added to ODCB to which an antioxidant (butylhydroxytoluene) was added so that the sample concentration was 0.05% by mass, and heated and dissolved at 140 ° C. 5 ml of this sample solution was poured into a column filled with glass beads while maintaining the column at 135 ° C., cooled to 25 ° C. at a cooling rate of 0.1 ° C./min, and the sample was deposited on the surface of the glass beads. . Next, the sample was sequentially eluted while increasing the column temperature at a constant rate of 50 ° C./hr while flowing ODCB through the column at a constant flow rate (1.0 ml / min). At this time, the concentration of the sample eluted in the solvent was continuously detected by measuring the absorption with respect to a wave number of 2925 cm ⁻¹ of the asymmetric stretching vibration of methylene with an infrared detector. From this value, the concentration of ethylene (co) polymer in the solution was quantitatively analyzed, and the relationship between elution temperature and elution rate was determined.

[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. The sample was held at 230 ° C. for 10 minutes and then 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 maximum temperature peak that appeared was defined as the maximum peak temperature Tml.

[ODCB soluble content]
0.5 g of the sample was added to 20 ml of ODCB and heated at 135 ° C. for 2 hours to completely dissolve the sample, and then cooled to 25 ° C. This solution was allowed to stand at 25 ° C. overnight and then filtered through a Teflon (registered trademark) filter to collect the filtrate. The absorption peak intensity in the vicinity of wave number 2925 cm ⁻¹ of the asymmetric stretching vibration of methylene in the filtrate as the sample solution was measured with an infrared spectrometer, and the sample concentration in the filtrate was calculated with a calibration curve prepared in advance. From this value, the ODCB soluble content at 25 ° C. was determined.

[Melt tension (MT)]
The stress when the molten 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 Seisakusho. The orifice to be 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 lowering speed of 20 mm / min, and a winding speed of 15 m / min.

[Halogen concentration]
When measured by a fluorescent X-ray method and 10 ppm or more of chlorine was detected, this was used as an analytical 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 2 ppm or less was considered to be substantially free of ND (non-detect).

Ethylene copolymer (A-1) was produced by the following method.
[Preparation of solid catalyst]
To a catalyst preparation apparatus equipped with an electromagnetic induction stirrer, 1000 ml of toluene purified under nitrogen, 26 g of tetrapropoxyzirconium (Zr (OPr) ₄ ), 22 g of indene and 88 g of methylbutylcyclopentadiene were added and tripropyl was maintained at 90 ° C. 100 g of aluminum was added dropwise over 100 minutes, and then reacted 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 stirred for 2 hours. Next, 2000 g of silica (surface area 300 m ² / g) fired at 450 ° C. for 5 hours in advance is added, stirred for 1 hour at room temperature, blown with nitrogen at 40 ° C., and dried under reduced pressure to give a solid catalyst (I )

[Gas phase polymerization]
Using a continuous fluidized bed gas phase polymerization apparatus, ethylene and 1-hexene were copolymerized at a polymerization temperature of 65 ° C. and a total pressure of 20 kgf / cm ² G ( ² MPaG). The solid catalyst (a) was continuously supplied, and ethylene, 1-hexene, hydrogen, and the like were supplied so as to maintain a predetermined molar ratio, and polymerization was performed to obtain an ethylene copolymer (A-1). The measurement results of the physical properties of the copolymer are shown in Table 1.

The ethylene copolymer (A-2) was produced by the following method.
[Preparation of solid catalyst]
To a catalyst preparation apparatus equipped with an electromagnetic induction stirrer, 1000 ml of toluene purified under nitrogen, 26 g of tetrapropoxyzirconium (Zr (OPr) ₄ ), 74 g of indene and 78 g of methylpropylcyclopentadiene were added and tripropyl was maintained at 90 ° C. 100 g of aluminum was added dropwise over 100 minutes, and then reacted 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 stirred for 2 hours. Next, 2000 g of silica (surface area 300 m ² / g) calcined at 450 ° C. for 5 hours in advance is added, stirred at room temperature for 1 hour, blown with nitrogen at 40 ° C. and dried under reduced pressure to give a solid catalyst with good fluidity (b) )

[Gas phase polymerization]
Using a continuous fluidized bed gas phase polymerization apparatus, ethylene and 1-hexene were copolymerized at a polymerization temperature of 80 ° C. and a total pressure of 20 kgf / cm ² G ( ² MPaG). The solid catalyst (b) was continuously supplied, and ethylene, 1-hexene and hydrogen were supplied so as to maintain a predetermined molar ratio, and polymerization was performed to obtain an ethylene copolymer (A-2). The measurement results of the physical properties of the copolymer are shown in Table 1.

The ethylene copolymer (A-3) was produced by the following method.
Using a Ziegler catalyst containing titanium tetrachloride, triethylaluminum, and magnesium chloride, ethylene and 1-butene were copolymerized by a gas phase method to obtain an ethylene copolymer (A-3). The physical properties are shown in Table 1.

[Resin used]
((A) component)
A-1: An ethylene-1-hexene copolymer (sLLDPE) obtained using a single site catalyst and satisfying the requirements of (a) to (d) (density = 0.915 g / cm ³ , MFR = 3.5 g / 10 min).
A-2: An ethylene-1-hexene copolymer (sLLDPE) obtained by using a single-site catalyst and satisfying the requirements (a) to (d) (density = 0.930 g / cm ³ , MFR = 3.5 g / 10 min).
A-3: an ethylene-1-butene copolymer (zLLDPE) obtained using a Ziegler catalyst and not satisfying some of the requirements (a) to (d) (density = 0.930 g / cm) ³ , MFR = 2.3 g / 10 min).

((B) component)
B-1: High density polyethylene (HDPE)
(Density = 0.953 g / cm ³ , MFR = 1.0 g / 10 min,
Nippon Polyolefin Co., Ltd., product name KS368S additive-free product).
B-2: High density polyethylene (HDPE)
(Density = 0.953 g / cm ³ , MFR = 5.0 g / 10 min,
Nippon Polyolefin Co., Ltd., product name KM568A additive-free product).
((C) component)
C-1: High-pressure low-density polyethylene (LDPE)
(Density = 0.922 g / cm ³ , MFR = 0.5 g / 10 min,
Nippon Polyolefin Co., Ltd., product name JB221R additive-free product).
C-2: High pressure low density polyethylene (LDPE)
(Density = 0.930 g / cm ³ , MFR = 3.0 g / 10 min,
Nippon Polyolefin Co., Ltd., product name JF454S additive-free product).

〔Additive〕
[Antioxidant]
(1) Brand: Irganox B910 (1: 1 blend of phenolic antioxidant (Irganox 1076) and phosphorus antioxidant (Irgaphos 168), manufactured by Ciba Geigy Special).
(2) Phosphorous antioxidant (Tris (2,4-di-tert-butylphenyl) phosphite, brand: Irgaphos 168, manufactured by Ciba Geigy Special).
(3) Vitamin E (brand: Riken Oil 100, manufactured by Riken Vitamin Co., Ltd.).
[Lubricant]
Oleic acid amide (brand: Neutron, manufactured by Nippon Seika Co., Ltd.).

〔Evaluation methods〕
(1) Transfer test: a packing material for packing is laid on a glass plate having a thickness of 5 mm so that the cell layer is in contact with it, a 10 cm × 10 cm stainless steel plate is placed thereon, a 5 kg load is applied, and 60 ° C. After 240 hours in an environment of × 85% RH, the transfer state of the glass surface was visually observed and evaluated in five stages.
(Transfer level)
Level a: No transfer.
Level b: A slight trace is seen through the light beam.
Level c: The shape trace of the cell can be confirmed by passing light.
Level d: The shape trace of the cell can be confirmed even on the desk.
Level e: The shape trace of the cell can be clearly confirmed even on the desk.

(2) Impact drilling strength: Conforms to JIS P8134. However, the shape of the penetrating portion was a half hemisphere in diameter.
(3) Coefficient of dynamic friction: Conforms to JIS K7125. As a friction object, a block polypropylene injection-molded plate coated with an acrylic melamine paint was used (coating film = 30 to 50 μm, baking condition: 90 ° C. × 20 minutes).
(4) Oxygen induction period (OIT):
Using an oxygen induction period measuring device (device connecting SSC5020 disk station and thermal analysis module DSC200: manufactured by Seiko Denshi Kogyo Co., Ltd.), 5 mg of a sample was placed in an aluminum pan, and 100 cc / min. While flowing nitrogen gas at a flow rate of 50 ° C./min. The temperature was raised from 30 ° C to 210 ° C. Then, after leaving at 210 ° C. for 5 minutes, the nitrogen gas was switched to oxygen gas and 100 cc / min. The OIT was defined as the heat increase start time.

[Examples 1 to 5, Comparative Examples 1 to 4]
(A) ethylene (co) copolymer (sLLDPE: A-1, A-2, zLLDPE: A-3), (B) high density polyethylene (HDPE: B-1, B-2) and (C) high pressure Radical method ethylene polymers (LDPE: C-1, C-2) were mixed at the ratio shown in Table 2. Various additives were added at a blending amount shown in Table 2 with respect to 100 parts by mass of the resin mixture to prepare a resin composition.
The obtained resin composition was measured for density and MFR. The results are shown in Table 2.

Using the resin composition, a cushioning material for packing (air chamber sheet) was produced as follows.
Using one extruder, two sheets of a molten thin film made of the resin composition were extruded from a double-head die, and these were introduced between an embossing roll and a pressure-bonding roll arranged opposite to each other. The embossing roll has a large number of recesses formed on the roll surface, and each recess is connected to a vacuum pump. Of the two films introduced between the embossing roll and the pressure-bonding roll, the film located on the embossing roll side is sucked into the recess when it comes into contact with the embossing roll, and a large number of protrusions are formed. The film was bonded to the film on the side of the pressure-bonding roll so as to sandwich air. Thereafter, the product is cooled with a cooling roll to produce a two-layer cushioning material (air chamber sheet) having a plurality of cylindrical cells (air chambers) having a bottom area of 0.8 cm ² and a height of 10 mm. did.
The obtained cushioning material for packing was evaluated, and the results are shown in Table 2.

  The cushioning material for packing according to the present invention has improved compressive fracture resistance, puncture resistance, etc., and does not have cell marks on the product or part being packaged. It is something to enhance. The packing cushioning material of the present invention can dramatically expand the use as a packing material for so-called air chamber sheets.

It is a graph which shows the elution temperature-elution amount curve of the (A) ethylene (co) polymer which concerns on this invention. It is a graph which shows the elution temperature-elution amount curve of the (A1) ethylene (co) polymer which concerns on this invention. It is a graph which shows the elution temperature-elution amount curve of the ethylene copolymer by a metallocene catalyst. It is a graph which shows the elution temperature-elution amount curve of the (A2) ethylene (co) polymer which concerns on this invention. It is a perspective view which shows an example of the shock absorbing material for packing of this invention. It is the perspective view which peeled a part of cushioning material for packing of FIG. It is a figure which shows the other example of the buffer material for packing of this invention, and is the perspective view which peeled one part.

Explanation of symbols

10 Packing cushioning material 12 Base film (film layer)
14 Embossed film (cell layer)
16 cells 20 cushioning material for packing 22 embossed film (cell layer)
24 Film (film layer)
26 Film (film layer)

Claims (13)

In a packing cushioning material having a plurality of sealed cells, which is formed by laminating a film layer to a cell layer in which a plurality of protrusions are formed,
The film layer and / or cell layer is
(A) 40 to 100% by mass of an ethylene (co) polymer that satisfies the following requirements (a) to (d);
(B) a linear low density polyethylene or a high density polyethylene of 0 to 30% by mass having a density of 0.93 to 0.96 g / cm ³ and a melt flow rate of 0.1 to 10 g / 10 min;
(C) 0-30% by mass of a high-pressure radical ethylene polymer having a melt flow rate of 0.1-10 g / 10 min (the sum of the components (A), (B) and (C) is 100% by mass),
A packing material comprising a resin composition having a density of 0.93 to 0.96 g / cm ³ and a melt flow rate of 1 to 10 g / 10 min.
(A) Density 0.91 g / cm ^{3 to} 0.96 g / cm ³ ,
(B) Melt low rate 0.1 to 10 g / 10 min,
(C) molecular weight distribution (Mw / Mn) is 1.5 to 4.5,
(D) Difference between temperature T _{25 at} which 25% of the elution is obtained from the integral elution curve of the elution temperature-elution amount curve by continuous temperature rising elution fractionation method (TREF) and temperature T _{75 at} which 75% of the elution is eluted T ₇₅ -T ₂₅ and density d satisfy the relationship of the following (formula 1).
(Formula 1) T ₇₅ −T ₂₅ ≦ −670 × d + 644   The resin composition comprises (A) 40 to 90% by mass of an ethylene (co) polymer, (B) 5 to 30% by mass of linear low-density polyethylene or high-density polyethylene, and (C) high-pressure radical method ethylene weight. The packing cushioning material according to claim 1, comprising 5 to 30% by mass of coalescence (total of (A) component, (B) component and (C) component is 100% by mass).   The packing material according to claim 1 or 2, wherein the resin composition contains an antioxidant of 700 ppm or less.   The packing cushioning material according to any one of claims 1 to 3, wherein the antioxidant is a natural antioxidant and a phosphorus antioxidant. The antioxidant is vitamin E and phosphorus antioxidant,
Vitamin E is 100 ppm or less in a resin composition, and phosphorus antioxidant is 600 ppm or less in a resin composition, The cushioning material for packing of Claim 4 characterized by the above-mentioned.   6. The packing cushioning material according to claim 2, wherein the antioxidant contains tris (2,4-di-tert-butylphenyl) phosphite. The temperature (T _{25) at} which 25% of the (A) ethylene (co) polymer is further eluted from the integral elution curve of the elution temperature-elution amount curve by (e) continuous temperature rising elution fractionation method (TREF) The packaging according to any one of claims 1 to 6, wherein the difference T ₇₅ -T ₂₅ and the density d from the temperature T _{75 at} which 75% of the total elution is satisfied satisfy the following relationship (Formula 2). Cushioning material.
(Formula 2) When d <0.950 g / cm ³ ,
T ₇₅ −T ₂₅ ≧ −300 × d + 285
When d ≧ 0.950 g / cm ³
T ₇₅ -T ₂₅ ≧ 0 The (A) ethylene (co) polymer is an (A1) ethylene (co) polymer that further satisfies the following requirements (f) and (g): The cushioning material for packing as described in a term.
(F) The amount X (mass%) of the ODCB soluble component at 25 ° C., the density d, and the MFR satisfy the relationship of the following (formula 3) and (formula 4).
(Formula 3) When d−0.008log MFR ≧ 0.93,
X <2.0
(Formula 4) When d−0.008 log MFR <0.93,
X <9.8 × 10 ³ × (0.9300−d + 0.008logMFR) ² +2.0
(G) There are a plurality of peaks of the elution temperature-elution amount curve by the continuous temperature rising elution fractionation method (TREF). The (A) ethylene (co) polymer is an (A2) ethylene (co) polymer that further satisfies the following requirements (h) and (i): The cushioning material for packing as described in a term.
(H) There is one peak of the elution temperature-elution amount curve by the continuous temperature rising elution fractionation method (TREF).
(I) It has one or more melting point peaks, and the highest melting point T _ml and density d satisfy the relationship of the following (formula 5).
(Formula 5) T _ml ≧ 150 × d-19 The packing material according to claim 9, wherein the (A2) ethylene (co) polymer further satisfies the following requirement (j).
(J) Melt tension (MT) and melt flow rate (MFR) satisfy the following (formula 6).
(Formula 6) logMT ≦ −0.572 × logMFR + 0.3   The cushioning material for packing according to any one of claims 1 to 10, wherein the (k) halogen concentration of the (A) ethylene (co) polymer is 10 ppm or less.   The (A) ethylene-based (co) polymer is polymerized by a catalyst containing at least an organic cyclic compound having a conjugated double bond and a transition metal compound of Group 4 of the periodic table. The cushioning material for packing as described in any one of 1 thru | or 11. In the cushioning material for packing having a plurality of sealed cells, which is formed by laminating a film layer on both surfaces of a cell layer on which a plurality of protrusions are formed,
At least one film layer
(A) 40 to 100% by mass of an ethylene (co) polymer that satisfies the following requirements (a) to (d);
(B) a linear low density polyethylene or a high density polyethylene of 0 to 30% by mass having a density of 0.93 to 0.96 g / cm ³ and a melt flow rate of 0.1 to 10 g / 10 min;
(C) 0-30% by mass of a high-pressure radical ethylene polymer having a melt flow rate of 0.1-10 g / 10 min (the sum of the components (A), (B) and (C) is 100% by mass),
A packing material comprising a resin composition having a density of 0.93 to 0.96 g / cm ³ and a melt flow rate of 1 to 10 g / 10 min.
(A) Density 0.91 g / cm ^{3 to} 0.96 g / cm ³ ,
(B) Melt low rate 0.1 to 10 g / 10 min,
(C) molecular weight distribution (Mw / Mn) is 1.5 to 4.5,
(D) Difference between temperature T _{25 at} which 25% of the elution is obtained from the integral elution curve of the elution temperature-elution amount curve by continuous temperature rising elution fractionation method (TREF) and temperature T _{75 at} which 75% of the elution is eluted T ₇₅ -T ₂₅ and density d satisfy the relationship of the following (formula 1).
(Formula 1) T ₇₅ −T ₂₅ ≦ −670 × d + 644

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