JP2002060555A - Polyolefin composite material and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyolefin composite material containing a laminar silicate, capable of stably keeping the dispersion state of the laminar silicate even if the composite material is kept at a temperature not less than the melting point of the polyolefin resin. SOLUTION: This polyolefin-based composite material consisting essentially of 100 pts.wt. polyolefin-based resin and 0.1-50 pts.wt. organized laminar silicate has >=6 nm average interlayer distance measured after keeping the composite material at the temperature >=+40 deg.C higher than the melting point of the polyolefin-based resin by an X-ray diffraction analysis, or <=50% maximum ratio of the numbers of particles having >=3 μm major axes before and after the retention.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin composite material in which a layered silicate is compounded for modifying a polyolefin resin, and a method for producing the same.

[0002]

2. Description of the Related Art There is known a method of dispersing a layered silicate in a thermoplastic resin in order to improve the mechanical properties, thermal properties, gas barrier properties and the like of the thermoplastic resin. In the layered silicate constituting the clay mineral, extremely fine flaky crystals are aggregated by ionic bonds. This aggregate structure is crushed by chemical or physical means,
By uniformly dispersing the flaky crystals in the thermoplastic resin, the properties of the thermoplastic resin are improved.

For example, Japanese Patent Publication No. Hei 8-22946 discloses that
By intercalating the aminocarboxylic acid into the layered silicate to increase the distance between the layers in advance, and then inserting the polyamide monomer ε-caprolactam between the layers and simultaneously performing polycondensation, the layered silicate in the polyamide resin is removed. It is disclosed that a structure in which flakes of salt are uniformly dispersed can be formed.

However, for polymers other than those capable of intercalating monomers between layered silicates, such as polyamides,
It is generally very difficult to uniformly disperse the layered silicate in the matrix. Various attempts have been made to solve this problem.

For example, Japanese Patent Application Laid-Open No. 9-183910 discloses that a layered silicate is mixed in a polymer by mixing an organic dispersion obtained by swelling and dispersing an organized layered silicate with a vinyl polymer compound in a dissolved state. A method of dispersing is disclosed. JP-A-10-182892 discloses that an organically modified layered silicate, a polyolefin oligomer containing a hydrogen bonding functional group, and a polyolefin polymer are melt-kneaded to infinitely swell between layers of the layered silicate in the polymer. It is disclosed that the polyolefin-based resin composite material can be prepared. According to these methods,
The layered silicate can be dispersed in the polymer.

[0006]

However, Japanese Patent Application Laid-Open Nos. Hei 9-183910 and Hei 10-182892 disclose.
According to the method described in Japanese Patent Application Laid-Open Publication No. H10-260, it was found that when the obtained composite material was kept at a temperature equal to or higher than the melting point of the polymer for a while, remarkable agglomeration of flaky crystals of the layered silicate occurred. FIG.
FIG. 1 is a schematic diagram of an optical microscope photograph at room temperature of a composite material obtained by the method described in JP-A-10-182892. FIG. 6 is a schematic view of an optical micrograph showing the state after re-melting the composite material at a temperature of 200 ° C. and holding it for 5 minutes. In FIGS. 5 and 6, the numbers in the figures indicate the aggregated portions.

As shown in FIG. 5, large aggregates are not observed before melting, whereas in FIG. 6, which shows a state after melting, many large aggregated particles are present.
The size of the agglomerated particles has a major axis of about 3 to 50 μm and is generated by agglomeration of flaky crystals of layered silicate.

As described above, in the conventional layered silicate-containing composite material, when exposed to a temperature higher than the melting point of the polymer used, flake-like crystals of the layered silicate are aggregated,
The effect obtained by dispersion of the flaky crystals is significantly impaired. That is, the mechanical properties, thermal properties, gas barrier properties, and other properties of the composite material are significantly impaired after the melting process.

[0009] In general industrial processes, in many cases, a molded product once obtained is melted and used again to be used as a master batch or to reuse materials. However, when the composite material is melted again, the dispersibility of the layered silicate is remarkably reduced, and it is difficult to exhibit characteristics as a composite material in which the layered silicate is dispersed again.

An object of the present invention is to solve the above-mentioned disadvantages of the prior art and to provide a layered silicate in which the dispersion state of the layered silicate is stably maintained even when the temperature is maintained at a temperature higher than the melting point of the polymer used. An object of the present invention is to provide a salt-containing polyolefin-based composite material and a method for producing the same.

[0011]

According to a first aspect of the present invention, there is provided a polyolefin composite material comprising 100 parts by weight of a polyolefin resin and 0.1 to 50 parts by weight of an organically modified layered silicate. After maintaining the polyolefin-based composite material at a temperature of melting point + 40 ° C. or more, the average interlayer distance of the organically modified layered silicate detected by X-ray diffraction measurement is 6 nm or more.

The second invention relates to a polyolefin resin 10
A polyolefin-based composite material comprising 0% by weight and 0.1 to 50 parts by weight of an organically modified layered silicate, wherein the long diameter of the polyolefin-based composite material is 3 μm after the polyolefin-based composite material is maintained at a temperature equal to or higher than the melting point of the polyolefin-based resin + 40 ° C. It is characterized in that the increase ratio of the above-mentioned number of particles before and after holding is 50% or less.

In a specific aspect of the first and second inventions, a nucleating agent is further contained in an amount of 0.5 to 10 parts by weight, whereby the precipitation of polyolefin crystals is suppressed, and Good dispersibility is maintained. Preferably, a rosin-based crystal nucleating agent or a sorbitol-based crystal nucleating agent is used as the crystal nucleating agent, and the dispersed state of the organically modified layered silicate is more favorably maintained.

In a specific aspect of the first and second inventions, the gel fraction of the polyolefin-based resin in the polyolefin-based composite material is set to 5% or more, whereby the molecular weight of the polyolefin-based resin as a matrix in a remelted state is determined. The movement is suppressed, and the dispersed state of the organically modified layered silicate is favorably maintained.

[0015] In still another specific aspect of the first and second inventions, the organically modified layered silicate is chemically bonded to a polyolefin-based resin, whereby the organically modified layered silicate is remelted. A good dispersion state is maintained.
Preferably, the chemical bond is achieved by a silane coupling agent and / or a titanate coupling agent.

In the polyolefin-based composite material according to the first and second aspects of the present invention, the layered silicate constituting the above-mentioned organically modified layered silicate is preferably a swellable smectite-based viscous mineral and / or swellable mica. Can be

The polyolefin resin is preferably an ethylene homopolymer, ethylene and α-
At least one of a copolymer with an olefin, an ethylene-propylene copolymer, a propylene homopolymer, and a copolymer of propylene and an α-olefin is used.

The polyolefin-based composite material according to the present invention can be obtained, for example, by the following production method. In one aspect of the method for producing a polyolefin-based composite material according to the present invention, 100 parts by weight of the polyolefin-based resin, 0.1 to 50 parts by weight of an organically modified layered silicate, 0.5 to 10 parts by weight of a crystal nucleating agent, and melt kneading. By doing so, a polyolefin-based composite material is obtained.

In another specific aspect of the method for producing a polyolefin composite material according to the present invention, the gel fraction of the polyolefin resin is set to 5% or more during the production process of the polyolefin composite material. Further, in still another aspect of the production method of the present invention, the organically modified layered silicate is chemically bonded to the polyolefin-based resin at a temperature equal to or lower than the melting point of the polyolefin-based resin.

Hereinafter, the present invention will be described in detail. In the present invention, the above-mentioned layered silicate means a silicate mineral having a plurality of layers composed of a large number of fine flaky crystals and having exchangeable cations between the layers. This flaky crystal is usually
The thickness is about 1 nm, and the ratio of the major axis to the thickness (hereinafter, referred to as aspect ratio) is about 20 to 200. In the layered silicate, these fine flaky crystals are aggregated by ionic bonds.

The type of the layered silicate having exchangeable cations between the layers is not particularly limited, and examples thereof include smectite clay minerals such as montmorillonite, saponite, hectorite, beidellite, stevensite, and nontronite; vermiculite. , Natural mica such as halloysite;
Alternatively, synthetic mica such as swellable mica (swellable mica) can be used, and it may be a natural product or a synthetic product. Preferably, a swellable smectite clay mineral or swellable mica is used.

The above-mentioned layered silicates may be used in combination of two or more. In addition, the layered silicate has a function in which the flaky crystal functions as a partition wall to enhance the gas barrier property of the composite material. Therefore, the higher the aspect ratio of the lamellar silicate flake crystal, the higher the gas barrier property. Therefore, montmorillonite having an aspect ratio of about 100 and swelling mica having an aspect ratio of about 150 are preferably used in applications requiring gas barrier properties.

The structure of a layered silicate crystal flake is shown schematically in FIG. FIG. 2 is a schematic diagram of the crystal structure of montmorillonite in which the cubic portion X shown in FIG. 1 is enlarged.
The layered silicate has exchangeable cations existing between layers. The exchangeable cation is generally a sodium ion or a calcium ion on the crystal surface (B). Since these ions have an ion exchange property with a cationic substance, various cationic substances can be inserted between layers.

In the present invention, an organically modified layered silicate is used. The term "organized layered silicate" refers to a layered silicate in which layers are ion-exchanged by a chemical species having a hydrophobic group. The organically modified layered silicate has a high affinity for a polyolefin-based resin, which is a non-polar resin, because the interlayer is made hydrophobic.

The hydrophobicization between the layers is carried out by ion-exchanging the exchangeable cations existing between the layers of the layered silicate with a cationic surfactant. Generally, the exchangeable cations existing between the layers of the layered silicate (that is, the flaky crystal surface) are usually ions such as sodium and calcium, and these ions are exchangeable with the exchangeable cations of the cationic surfactant. Has ion exchangeability. Therefore, various cationic surfactants having exchangeable cations can be inserted between the layers.

Therefore, by using a low-polarity cationic surfactant to ion-exchange the exchangeable cation with the exchangeable ion of the cationic surfactant, the crystal surface of the layered silicate becomes nonpolar. Alternatively, the dispersibility of the layered silicate in the non-polar resin can be enhanced by making the polarity low.

As described above, the exchangeable cation is usually an ion of an alkali metal such as sodium or calcium or an alkaline earth metal, and the exchangeable cation is more than the exchangeable cation. Also, base or equivalent ions are used.

When an ion equivalent to the exchangeable cation is used, the concentration of the exchangeable cation may be higher than the concentration of the exchangeable cation. The cationic surfactant is not particularly limited, and a commonly used cationic surfactant is used. Examples thereof include those mainly containing a quaternary ammonium salt, a quaternary phosphonium salt, and the like. A quaternary ammonium salt having an alkyl chain having 8 or more carbon atoms is used. When an alkyl chain having 8 or more carbon atoms is not contained, the alkyl group ammonium ion has high hydrophilicity, and it is difficult to sufficiently non-polarize or reduce the polarity between the layers of the layered silicate.

Examples of the quaternary ammonium salt include lauryl trimethyl ammonium salt, stearyl trimethyl ammonium salt, trioctyl ammonium salt, distearyl dimethyl ammonium salt, di-hardened tallow dimethyl ammonium salt, distearyl dibenzyl ammonium salt and the like. Can be

The cation exchange capacity of the above layered silicate is not particularly limited, but if it is too small, the amount of the cationic surfactant intercalated by ion exchange between the crystal layers is small, so that the interlayer is sufficiently hydrophobicized. In some cases, if the amount is too large, the bonding strength between the layers of the layered silicate becomes strong, and it may be difficult to delaminate (delaminate) the crystal flakes, so 50 to 200 meq / 100 g.
It is preferred that

Further, in the polyolefin-based composite material according to the present invention, 100 parts by weight of the polyolefin-based resin is
The organically modified layered silicate is used in the range of 0.1 to 50 parts by weight. If the amount is less than 0.1 part by weight, the effect of dispersing the organically modified layered silicate cannot be obtained. If the amount exceeds 50 parts by weight, the tendency to be hard and brittle is increased in physical properties, and the formability and appearance are impaired. .

The polyolefin resin used in the present invention is not particularly limited, and a homopolymer of ethylene, propylene or α-olefin; a copolymer of ethylene and propylene, a copolymer of ethylene and α-olefin, And α-olefin copolymers, and copolymers of two or more α-olefins. The above α
-As the olefin, for example, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-
Heptene, 1-octene and the like.

These polyolefin resins may be used alone or in combination of two or more. The molecular weight and molecular weight distribution of the polyolefin-based resin are not particularly limited, and the weight average molecular weight is preferably from 5,000 to 5,000,000.
0, more preferably 20,000 to 300,000, and the molecular weight distribution (weight average molecular weight Mw / number average molecular weight M
n) is preferably 2 to 80, more preferably 3 to 4
It is set to 0.

The above-mentioned polyolefin resin may be alloyed or blended with another kind of polymer compound as appropriate. For example, a small amount of a polymer compound to which a carboxylic acid such as maleic acid is grafted may be added, and the affinity between the polyolefin resin and the layered silicate may be increased in advance.

The average interlayer distance of the organically modified layered silicate in the polyolefin composite material according to the present invention, which is detected by X-ray diffraction measurement, is preferably 6 nm or more. Generally, the reinforcement of a polymer with an inorganic material is based on the polymer /
The larger the area of the inorganic interface, the more efficiently it is made. Therefore, when the phyllosilicates are cohered to each other due to the ionic bonding force, that is, when the phyllosilicates exist at an interlayer distance of about 1 to 2 nm, the modification effect by the addition of the phyllosilicate is very small. Only after the flaky crystals of the layered silicate can be dispersed in the polymer can the properties of the composite material such as mechanical strength, heat resistance and gas barrier properties be significantly improved. Generally, the interlayer attraction of a layered silicate is
Since the distance between the layers becomes extremely small when the layers are peeled to 6 nm or more, it is important to set the average interlayer distance to 6 nm or more.

The interlayer distance defined in the present invention is:
It refers to the plane distance between the 001 planes of the lamellar silicate flake crystal, that is, the distance between the centers of the two flake crystals in FIG. The average interlayer distance defined in the present invention is calculated by obtaining the distance between flaky crystals and the amount of silicate at the distance between the flaky crystals by X-ray diffraction. The following are two typical examples. FIG. 3 shows an X-ray diffraction profile when the average interlayer distance is 6 nm or more, and FIG. 4 shows an X-ray diffraction profile when the average interlayer distance is less than 6 nm. That is, in FIG. 3, although a small diffraction peak is observed at the position of the interlayer distance of 2 nm, most of the interlayer distance can be confirmed by a broad diffraction line of 6 nm or more.

As described above, even if the lamellar silicate flaky crystals are sufficiently dispersed in the composite material, the composite material is again kept at a temperature equal to or higher than the melting point of the polyolefin resin and further solidified. As described above, agglomerated particles are generated due to agglomeration of the flaky crystals of the layered silicate.

In the polyolefin composite material according to the present invention, even when the re-melting treatment is performed in this way, the dispersion state of the flaky crystals of the lamellar silicate is maintained well, and the generation of the agglomerated particles is effectively suppressed. can do. This is described in more detail below. The reason why the dispersibility of the layered silicate is impaired during the heat treatment as described above is considered to be as follows.

(1) Polyolefins are inherently very hydrophobic and are essentially incompatible with substances having a hydrophilic surface such as layered silicates. In the present invention, the affinity of the layered silicate with the polyolefin is increased by organizing the layered silicate, but since the layered silicate locally leaves a hydrophilic surface, the layered silicate aggregates with each other. Tend to try.

(2) When the polyolefin is cooled, depending on the cooling conditions, spherulites or crystals having a diameter of several tens of μm are precipitated, and the layered silicate is eliminated by this crystal growth.
Aggregates at the crystal interface.

The inventors of the present invention have found that the addition of a crystal nucleating agent can suppress the precipitation of giant crystals, thereby maintaining the dispersion state of the layered silicate well.

The nucleating agent is not particularly limited, but may be a rosin-based nucleating agent such as a rosin acid partial metal salt,
A soluble crystal nucleating agent such as a crystal nucleating agent represented by a dibenzylidene sorbitol compound can be preferably used.

Examples of the dibenzylidene sorbitol compound include dibenzylidene sorbitol, bis (dimethylbenzylidene) sorbitol, bis (diethyl benzylidene) sorbitol, bis (dipropyl benzylidene) sorbitol, bis (dibutyl benzylidene) sorbitol, bis (hexyl benzylidene) sorbitol, Bis (dichlorobenzylidene) sorbitol and the like;
These may be used alone or in combination.

As an available commercially available crystal nucleating agent, KM1
Rosin-based crystal nucleating agents such as 500, KM1300 (manufactured by Arakawa Chemical), EC1, EC1-55, EC-4 (manufactured by EC Chemical), gelol MD, gelol D, gelol MD-R, gelol DH, gelol T (Manufactured by Nippon Rika Co., Ltd.).

Among them, the rosin-based crystal nucleating agent gives a polymer crystal nucleus to the surface of the layered silicate because the metal or hydrophilic group in the structure has a strong affinity for the local hydrophilic portion of the layered silicate. Cheap. That is, the crystal growth of the polymer proceeds preferentially on the surface of the layered silicate, and the elimination of the layered silicate due to the crystal growth and the aggregation at the crystal interface are suppressed. Therefore, even when the melted composite material is solidified again, the dispersion state of the flaky crystals of the layered silicate is well maintained.

In another aspect of the present invention, the gel fraction of the polyolefin resin in the composite material is 5% in view of the fact that the movement of the layered silicate in the polymer matrix during remelting is also a factor of aggregation. As described above, the molecular motion of the polyolefin resin is suppressed, and the dispersion state of the layered silicate is favorably maintained.

The gel fraction of the polyolefin resin is set to 5
% Or more, a method in which a crosslinkable functional group is present in the polymer matrix, and a method of crosslinking with an external stimulus such as heat, ultraviolet light, or an electron beam, or using a polymer grafted with a silane coupling agent or the like. A method of cross-linking the matrix resin by hydrolysis and condensation, and a method of directly applying an external stimulus such as an electron beam to perform intermolecular cross-linking. The crosslinkable functional group is not particularly limited, and examples thereof include a vinyl group, an allyl group, an acryl group, and a methacryl group. The silane coupling agent is not particularly limited, and examples thereof include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane and the like.

In another specific aspect of the present invention, the layered silicate is grafted onto molecules of a polyolefin resin which is a matrix resin in order to prevent the layered silicate from moving in the matrix during remelting. You.

As shown in FIG. 1, generally, the layered silicate often has a hydroxyl group on the crystal end face, that is, on the crystal surface (A). Therefore, various chemical bonds can be formed through the hydroxyl groups. Examples of the compound having a functional group capable of binding to the hydroxyl group include a silane compound, a titanate compound, a glycidyl compound, a carboxylic acid, and an alcohol having the functional group. Preferably, the functional group is an alkoxysilyl group. As the alkoxysilyl group-containing compound,
General silane coupling agents are exemplified. The specific structure of the alkoxysilyl group-containing compound is represented by the following formula (1).

[0050]

Embedded image

In the formula (1), R1 is not particularly limited, but an alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a hexyl group, an octadecyl group; an aminopropyl group, N-β (aminoethyl) A reactive functional group such as a γ-aminopropyl group, a vinyl group, an epoxy group, a maleic anhydride group, an alkoxy group, an alkoxyl group, and a hydroxyl group can be used.

Any of R2 to R4 is preferably an epoxy group, a carboxyl group, a hydroxyl group, a maleic anhydride group, an isocyanate group or an aldehyde group, and more preferably has an alkoxysilyl group. When any one of R2 to R4 chemically bonds to the above-mentioned hydroxyl group on the surface of the layered silicate or is not a functional group having a chemical affinity, the structure thereof is not particularly limited, and examples thereof include a methyl group and an ethyl group. An alkyl group can be exemplified.

Specific examples of the compound represented by the formula (1) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyl Dimethoxysilane, γ-aminopropyldimethylmethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropyldimethylethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane,
Trimethylmethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β
(Aminoethyl) γ-aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, octadecyltrimethoxysilane,
Octadecyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane and the like can be mentioned.

If the end face of the organically modified layered silicate is previously treated with a compound as described above, for example, vinyltrimethoxysilane, the organically modified layered silicate is melt-kneaded with a polyolefin and further molded to form a composite material. After obtaining the composite material, the composite material is irradiated with an electron beam, so that the vinyl group and the polyolefin main chain are bonded, and the movement of the organically modified layered silicate accompanying the heat treatment is suppressed.

Further, for example, a polyolefin resin in which the above-mentioned vinyltrimethoxysilane is grafted in advance and an organically modified layered silicate are melt-kneaded and molded to obtain a composite material, and the composite material is impregnated with hot water. , The alkoxysilyl group and the hydroxyl group on the end face of the organically modified layered silicate can be bonded. Therefore, the movement of the organically modified layered silicate accompanying the heat treatment is suppressed.

In the polyolefin-based resin composite material according to the present invention, after maintaining at a temperature of not less than the melting point of the polyolefin-based resin + 40 ° C., the average interlayer distance of the organized layered silicate detected by X-ray diffraction measurement is at least 6 mm. Alternatively, the rate of increase in the number of particles having a major axis of 3 μm or more before and after holding is 50% or less. The number of particles having a major axis of 3 μm or more can be easily observed with an optical microscope. If the average interlayer distance is less than 6 mm, or if the increase rate of the particles is more than 50%, properties such as elastic modulus and gas barrier properties of the composite material are significantly impaired.

[0057]

Next, the present invention will be described in detail with reference to examples and comparative examples, but the present invention is not limited to these examples. Raw materials used in the following Examples and Comparative Examples will be described. A: Raw materials used

(1) Layered silicate The following minerals were used as the layered silicate.・ Montmorillonite: Montmorillonite manufactured by Toyshun Mining (trade name: Wenger A) ・ Swelling mica: swelled mica manufactured by Corp Chemical (trade name: ME-100)

(2) Organized layered silicate The following commercially available products containing a cationic surfactant between layers were used as the organized layered silicate.・ DSDM-modified montmorillonite: Toyshun Mining DSDM
Modified montmorillonite (trade name: New Esven D = organized montmorillonite obtained by ion-exchange of all sodium ions between montmorillonite layers with disterial dimethyl ammonium chloride) -DSDM-modified swelling mica: DSD manufactured by Corp Chemical
M-modified swellable mica (trade name; MAE = organized swellable mica obtained by ion exchange of all sodium ions between montmorillonite layers with distearyldimethylammonium chloride)

(3) Vinyltrimethoxysilane-treated montmorillonite Vinyltrimethoxysilane (manufactured by Wako Pure Chemical Industries, Ltd.) was dropped at 2% by weight based on the solid content while stirring DSDM-modified montmorillonite manufactured by Toyoko Mining Co., Ltd. in a Henschel mixer.

(4) Polyolefin resin The following commercial products were used as the polyolefin resin. -Polypropylene: (Japan Polychem, trade name; EA9,
・ Density 0.91, MFR = 0.5 ・ Polyethylene: (Nippon Polychem, trade name; HB53)
0, density 0.96, MFR = 0.5) Silane-modified polyethylene (Nippon Polychem, trade name; Linklon, density 0.94, MFR = 2.1)

(5) Acid-Modified Polyolefin Resin The following commercially available products were used to increase the affinity between the polyolefin resin and the layered silicate. -Maleic anhydride-modified polypropylene oligomer: (trade name, manufactured by Sanyo Chemical; Umex 1001, functional group content = 0.23 mmol / g)-Maleic anhydride-modified polyethylene oligomer: (trade name, manufactured by Sanyo Chemical; Umex 2000, containing functional group) Amount = 0.92 mmol / g)

(6) Crystal nucleating agent The following commercial products were used as the crystal nucleating agent.・ Rosin-based crystal nucleating agent (Arakawa Chemical: KM1500) ・ Sorbitol-based crystal nucleating agent (Shin Nippon Rika, product name: Gelol MD)

(7) Polyethylene polymerization reagents The following commercially available products were used as polyethylene polymerization reagents.・ Dicyclopentadienyl titanium dichloride (Aldrich) ・ Methylalmonoxane (Aldrich)

(8) Crosslinking Aids The following commercial products were used as crosslinking aids. -Trimethylpentatriacrylate (trade name, manufactured by NOF CORPORATION; light ester TPMTA) B: Layered silicate dispersion method The dispersion of the layered silicate was performed by the following methods (1) to (3). The method (1) is described in Japanese Patent Application Laid-Open No. 10-182.
This is the same as the method described in JP-A-892.

(1) (Examples 1 to 5, 11 and Comparative Example 1)
４4, Comparative Example 9) A polypropylene resin (Nippon Polychem, trade name; EA9, density 0.91, MF) was placed in Labo Plastomill manufactured by Toyo Seiki Co., Ltd.
R = 0.5), polyethylene resin (Nippon Polychem, trade name; HB530, density 0.96, MFR = 0.5), silane-modified polyethylene resin (Nippon Polychem, trade name; Linklon, density 0.94, MFR) = 2.1), a polyethylene resin or a silane-modified polyethylene resin, and a maleic anhydride-modified polypropylene oligomer (manufactured by Sanyo Chemical Industries, Ltd.)
Trade name: Umex 1001, functional group content = 0.2
3 mmol / g), or maleic anhydride-modified polyethylene oligomer (trade name, manufactured by Sanyo Chemical Industries; Umex 2)
000, functional group content = 0.92 mmol / g), and COP Chemical DSDM-modified swelling mica (trade name: MAE)
Alternatively, OSDM-modified montmorillonite (trade name: New Esven D) manufactured by Toyoshun Mining was supplied at a weight ratio of 80/5/10 as shown in Table 1 below. If necessary, as shown in Table 1 below, desired nucleating agents were supplied in the amounts shown in Table 1 below. The mixture was melted and kneaded at a set temperature of 200 ° C. in an N ₂ gas atmosphere for 10 minutes. The obtained composite material composition is taken out in a molten state, quickly charged into a mold, and the mold contents are pressed at 100 kg / cm ^{2 for} 1 minute, and the mold is rapidly cooled to room temperature. A sheet having a thickness of 1 mm was formed.

(2) (Examples 6, 8 to 10, and 12 and Comparative Examples 5, 7, 8, and 10) A polyolefin resin and an organically modified layered silicic acid as shown in Table 1 below were placed in a Labo Plastomill manufactured by Toyo Seiki. 9 parts by weight salt
Feed at a ratio of 5/5, and set the temperature to 200 ° C for 1
The mixture was melt-kneaded for 0 minutes.

The obtained composite composition was melt-pressed for 20 minutes.
By preheating at 0 ° C. for 5 minutes and pressing at 100 kg / cm ^{2 for} 1 minute, a 1 mm thick sheet was formed. A sheet having a thickness of 1 mm was cut into a 3 cm square, sealed in an autoclave, and the internal temperature of the autoclave was set to a temperature higher by 10 ° C. than the melting point or glass transition temperature of the polyolefin resin. Next, carbon dioxide gas or nitrogen gas is injected into the autoclave at a high pressure, and the autoclave is set to 30 kg / cm ² at an internal pressure of 170 kg / cm ^2.
Hold for minutes. Further, the temperature in the autoclave is set to be 10 points lower than the melting point or glass transition temperature of the polyolefin resin.
The temperature in the autoclave was set at a low temperature of ° C, and the gas in the autoclave was evacuated at once, and the internal pressure was returned to normal pressure to obtain a foam.

(3) (Example 7, Comparative Example 6) 300 ml of distilled toluene was introduced into four 500 ml flasks, and 0.5 g of an organically modified layered silicate was added. After stirring for 1 hour at room temperature to confirm that the mixed slurry was transparent, the surroundings of the slurry were replaced with nitrogen to shut off the contact with the outside air. Further, 0.05 g of methylammonoxane was added to the mixed slurry, and the mixture was stirred for 15 minutes. 0.02 in advance for 100 ml of toluene
A solution in which g of dicyclopentadienyl dichloride was dissolved was added to the slurry, and ethylene gas was immediately fed.

After the reaction was continued for 3 hours, the contents of the flask were taken out, reprecipitated with methanol and washed repeatedly, and then a solid was taken out by filtration. C: Crosslinking Method Among the samples obtained as described above, as shown in Table 1, Examples 8 to 11 and Comparative Example 7 were subjected to the following crosslinking treatment as necessary.

(1) Electron Beam Crosslinking A sample to be subjected to electron beam crosslinking and electron beam irradiation was cut out to a thickness of 1 mm, and irradiated with 1 Mrad electron beam using an electron irradiation device manufactured by Nissin High Voltage.

(2) Hot Water Crosslinking A sample to be subjected to hot water crosslinking was cut out to a thickness of 1 mm, and placed in a thermostat controlled at a temperature of 100 ° C. Then, 100 ° C. water vapor was introduced into the thermostat, and the pressure in the thermostat was set to 1.2 atm. After the treatment was performed for 5 hours, a sample was taken out. D: Evaluation method The samples obtained as described above and the samples subjected to post-treatment were evaluated in the following manner. Table 2 shows the results.

(1) Gel Fraction A sample to be subjected to gel fraction measurement was cut into slices having a thickness of 0.1 mm, and 3 g of the slice was introduced into xylene heated to 110 ° C. After 8 hours, the flakes were taken out, residual xylene was distilled off and dried, and the gel fraction was calculated according to the following equation.

(Formula 2) Gel fraction (%) = 100 × (sample weight after hot xylene treatment / sample weight before hot xylene treatment)

(2) Change in agglomeration state due to heat treatment The sample obtained by the above method was cut out to a thickness of 30 μm by a microtome, and 3 m thick was observed by an optical microscope.
The number of particles having a long piece of 3 μm or more in an m-angle visual field was counted. Further, the sample was heated at a melting point of the sample + 40 ° C by a hot stage installed on a sample stage of the optical microscope.
, And the number of particles whose long pieces were 3 μm or more in a 3 mm square visual field at this time was counted.

(3) Flexural Modulus A test piece was cut out from the sample 1 mm thick plate obtained by the above method, and the melting point of the polyolefin resin was +40.
After maintaining at a temperature of 5 ° C. for 5 minutes, solidifying again,
The flexural modulus was measured using a Tensilon tester according to the method specified in ISK7207.

With respect to the samples (Examples 6, 8 to 10, and 12 and Comparative Examples 5, 7, 8, and 10) obtained by the method of layered silicate dispersion (2), the samples have a foamed shape. Therefore, this evaluation was not performed.

(4) Oxygen permeability A test piece was cut out from a 100 μm thick plate obtained by the above-mentioned method, and the melting point of the polyolefin resin was measured.
After maintaining the temperature at 40 ° C. for 5 minutes, the mixture was solidified again, and the oxygen gas permeation rate was measured with an oxygen permeability tester (manufactured by Modern Control Co., Ltd .; device name: Oxtran-Twin).

With respect to the samples (Examples 6, 8 to 10, 12 and Comparative Examples 5, 7, 8, 10) obtained by the method of layered silicate dispersion (2), the samples have a foamed body shape. Therefore, this evaluation was not performed.

(5) Interlayer distance between layered silicates After maintaining the temperature at the melting point of the polyolefin-based resin + 40 ° C. for 5 minutes, and then solidifying again, the X-ray diffractometer (manufactured by Rigaku; RINT1100) was used to measure the distance between the layers. The 2θ of the (100) plane obtained by diffraction of the layered silicate layer was measured, and the plane distance of the layered silicate was calculated using the black diffraction equation (3).

Λ = 2 dsin θ (3) (λ = 1.54, d: spacing between layered silicates, θ: diffraction angle) d obtained from equation (3) is referred to as an average interlayer distance. And E: Evaluation results Tables 1 and 2 show the details of the formulations of Examples and Comparative Examples and the evaluation results.

[0082]

[Table 1]

[0083]

[Table 2]

(1) Effect of Addition of Crystal Nucleating Agent According to the comparison of Examples 1 to 7 and Comparative Examples 1, 2, 4, and 5, any of the crystal nucleating agents showed that the generation of aggregates in the composite material due to the heat treatment was suppressed. It turns out that it has a remarkable effect in suppressing. As shown in Table 2, any polymer,
In the case where the organically modified layered silicate, the additive, and the dispersion method are used, when the crystal nucleating agent is added in an amount of 0.1 to 10 parts by weight, the increase of the particles having a long diameter of 3 μm or more is 50% or less. When no crystal nucleating agent was added, a remarkable increase in aggregated particles was confirmed. The decrease in the flexural modulus and the oxygen permeability with the increase of the aggregated particles is apparent from Table 2. Further, as shown in Comparative Example 3, when the nucleating agent is added in an excessive amount of 11% by weight, the effect of improving the elastic modulus and oxygen permeability is reduced.

(2) Effect of Increasing Gel Fraction According to a comparison between Examples 8 to 10 and Comparative Examples 5 to 8, an increase in the gel fraction of the composite material after dispersion was caused by the generation of aggregates in the composite material due to the heat treatment. It has been found to have a remarkable effect in suppressing odor. Regardless of which polymer, organically modified layered silicate, additive, or dispersion method is used, when the gel fraction is 5% or more by electron beam crosslinking or hot water crosslinking, particles having a long diameter of 3 μm or more increase. 50% or less,
When electron beam crosslinking or hot water crosslinking was not performed, a remarkable increase in aggregated particles was confirmed. Further, the decrease in the flexural modulus and the oxygen permeability with the increase of the aggregated particles is apparent from Table 2.

(3) Result of chemical bonding between polyolefin resin and layered silicate By comparing Examples 11 and 12 and Comparative Examples 9 and 10,
It can be seen that by chemically bonding the polyolefin-based resin and the layered silicate after the dispersion, the generation of aggregates in the composite material due to the heat treatment is significantly suppressed. In any case of using any of the polymers and the organically modified layered silicate, when the polyolefin resin and the layered silicate are chemically bonded after dispersion, the increase in the particles having a major axis of 3 μm or more is 50% or less, When no treatment was applied, a remarkable increase in aggregated particles was confirmed. Further, the decrease in the flexural modulus and the oxygen permeability with the increase of the aggregated particles is apparent from Table 2.

[0087]

According to the polyolefin composite material of the present invention, 0.1 to 50 parts by weight of the organically modified layered silicate is blended with respect to 100 parts by weight of the polyolefin resin. After holding at the temperature, the average interlaminar distance of the organically modified layered silicate detected by X-ray diffraction measurement is set to 6 nm or more, or the rate of increase in the number of particles having a long diameter of 3 μm or more before and after holding is 50% or less. For this reason, the dispersed state of the flaky crystals in the organically modified layered silicate is well maintained even when remelted. Therefore, by utilizing the polyolefin-based composite material according to the present invention and the method for producing the composite material, the polyolefin-based resin is modified with the layered silicate, that is, the elastic modulus is improved, the heat distortion temperature is increased, and the gas barrier property is improved. Not only can the polyolefin composite material according to the present invention be used as a masterbatch or re-melted when reused, the polyolefin-based composite material according to the present invention can exhibit the above various effects well. I do. Therefore, the industrial utilization value of the polyolefin composite material can be significantly increased.

[Brief description of the drawings]

FIG. 1 is a schematic view showing the structure of a crystal flake of a layered silicate.

FIG. 2 is an enlarged schematic view showing a cubic portion X of the crystal structure shown in FIG.

FIG. 3 is a view showing an X-ray diffraction profile of a layered silicate having an average interlayer distance of 6 nm or more.

FIG. 4 is a view showing an X-ray diffraction profile of a layered silicate having an average interlayer distance of less than 6 nm.

FIG. 5 is a schematic view of an optical microscope photograph of a conventional polyolefin-based composite material before heat treatment.

FIG. 6 is a schematic view of an optical microscope photograph of a conventional polyolefin-based composite material after heat treatment.

[Explanation of symbols]

 1: Layered silicate B: Crystal surface

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 23/06 C08L 23/06 23/08 23/08 23/12 23/12 23/14 23/14 23 / 16 23/16 93/04 93/04 (72) Inventor Koichi Shibayama 2-1 Momoyama, Shimamoto-cho, Mishima-gun, Osaka Prefecture Inside Sekisui Chemical Co., Ltd. (72) Koji Taniguchi Momoyama, Shimamoto-cho, Mishima-gun, Osaka 2-1 F-term in Sekisui Chemical Co., Ltd. (reference) 4J002 AF022 BB031 BB051 BB121 BB141 BB151 DJ006 DJ056 DM006 EC057 EC078 EX018 EX038 EX048 EX058 EX078 FA116 FD016 FD148 FD172 FD177

Claims (12)

[Claims] 1. A polyolefin-based composite material comprising 100 parts by weight of the polyolefin-based resin and 0.1 to 50 parts by weight of an organically modified layered silicate, wherein the polyolefin-based composite material is heated to a temperature equal to or higher than the melting point of the polyolefin-based resin + 40 ° C. A polyolefin-based composite material, wherein the average interlaminar distance of the organically modified layered silicate detected by X-ray diffraction measurement is 6 nm or more. 2. A polyolefin-based composite material comprising 100 parts by weight of a polyolefin-based resin and 0.1 to 50 parts by weight of an organically modified layered silicate, wherein the polyolefin-based composite material is heated to a temperature equal to or higher than the melting point of the polyolefin-based resin + 40 ° C. A polyolefin-based composite material, characterized in that the ratio of increase in the number of particles having a major axis of 3 μm or more before and after the holding is 50% or less after holding. 3. The polyolefin-based composite material according to claim 1, further comprising 0.5 to 10 parts by weight of a nucleating agent. 4. The polyolefin-based composite material according to claim 3, wherein the nucleating agent is a rosin-based nucleating agent or a sorbitol-based nucleating agent. 5. The polyolefin composite material according to claim 1, wherein the gel fraction of the polyolefin resin is 5% or more. 6. The polyolefin composite material according to claim 1, wherein the organically modified layered silicate is chemically bonded to the polyolefin resin. 7. The polyolefin-based composite material according to claim 6, wherein the chemical bonding is performed using a silane coupling agent and / or a titanate coupling agent. 8. The swellable smectite-based viscous mineral and / or swellable mica, wherein the layer silicate is swellable.
8. The polyolefin-based composite material according to any one of 7. 9. The polyolefin resin is an ethylene homopolymer, a copolymer of ethylene and an α-olefin,
The polyolefin composite material according to any one of claims 1 to 8, which is at least one of an ethylene-propylene copolymer, a propylene homopolymer, and a copolymer of propylene and an α-olefin. 10. The method for producing a polyolefin-based composite material according to claim 1, wherein 100 parts by weight of the polyolefin-based resin, 0.1 to 50 parts by weight of the organically modified layered silicate, and 0.1% of the nucleating agent. A method for producing a polyolefin-based composite material, comprising melt-kneading 5 to 10 parts by weight. 11. The method for producing a polyolefin composite material according to claim 1, wherein a gel fraction of the polyolefin resin is set to 5% or more during the step of producing the polyolefin composite material. A method for producing a polyolefin-based composite material. 12. The method for producing a polyolefin resin according to claim 1, wherein the organically modified layered silicate is chemically bonded to the polyolefin resin at a temperature equal to or lower than the melting point of the polyolefin resin. A method for producing a polyolefin-based composite material, comprising: