JP4865941B2 - Polyolefin-based composite material and method for producing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polyolefin-based composite material in which a layered silicate is combined to modify a polyolefin-based resin, and a method for producing the same.
[0002]
[Prior art]
In order to improve the mechanical properties, thermal characteristics, gas barrier properties, etc. of the thermoplastic resin, a method of dispersing a layered silicate in the thermoplastic resin is known. In the layered silicate constituting the clay mineral, extremely fine flaky crystals are aggregated by ionic bonds. The aggregated structure is disintegrated by chemical or physical means, and the flaky crystals are uniformly dispersed in the thermoplastic resin, whereby the properties of the thermoplastic resin are improved.
[0003]
For example, Japanese Patent Publication No. 8-22946 discloses intercalating aminocarboxylic acid into a layered silicate to widen the gap between layers in advance, and then inserting ε-caprolactam, which is a polyamide monomer, between the layers. It is disclosed that a structure in which lamellar silicate flakes are uniformly dispersed in a polyamide resin can be formed by condensation.
[0004]
However, it is generally very difficult to uniformly disperse the layered silicate in the matrix for polymers other than those capable of inserting monomers between the layers of the layered silicate, such as polyamide. Various attempts have been made to solve this problem.
[0005]
For example, Japanese Patent Application Laid-Open No. 9-183910 discloses a method of dispersing a layered silicate in a polymer by mixing an organic dispersion obtained by swelling and dispersing an organicated layered silicate and a vinyl polymer compound in a dissolved state. Is disclosed. JP-A-10-182892 discloses infinite swelling between layers of a layered silicate in a polymer by melt-kneading an organically modified layered silicate, a polyolefin oligomer containing a hydrogen bonding functional group, and a polyolefin polymer. It is disclosed that a polyolefin resin composite material can be prepared.
According to these methods, the layered silicate can be dispersed in the polymer.
[0006]
[Problems to be solved by the invention]
However, in the methods described in JP-A-9-183910 and JP-A-10-182892, when the obtained composite material is kept at a temperature equal to or higher than the melting point of the polymer for a while, significant aggregation of flaky crystals of layered silicate occurs. Was found to occur. FIG. 5 is a schematic view of an optical micrograph at room temperature of a composite material obtained by the method described in JP-A-10-182892. FIG. 6 is a schematic diagram of an optical micrograph showing a state after the composite material is remelted at a temperature of 200 ° C. and held for 5 minutes. In FIG. 5 and FIG. 6, the numbers in the drawings indicate the aggregated portions.
[0007]
As shown in FIG. 5, large aggregates are not observed before melting, whereas in FIG. 6 showing the state after melting, a large number of huge aggregated particles exist. The agglomerated particles have a major axis of about 3 to 50 μm and are produced by agglomeration of lamellar crystals of layered silicate.
[0008]
As described above, in the conventional layered silicate-containing composite material, when it is exposed to a temperature higher than the melting point of the polymer used, the flake crystals of the layered silicate aggregate and are obtained by dispersion of the flake crystals. The effect that is achieved is significantly impaired. That is, the properties of the composite material such as mechanical properties, thermal properties and gas barrier properties are significantly impaired after the melting treatment.
[0009]
In general industrial processes, in order to use as a master batch or reuse materials, there are many cases in which a molded product once obtained is melt-molded again. However, when the above composite material is melted again, the dispersibility of the layered silicate is remarkably lowered, and it becomes difficult to develop the characteristics of the composite material in which the layered silicate is dispersed again.
[0010]
The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to maintain a dispersion state of the layered silicate stably even if the temperature is maintained at a temperature higher than the melting point of the polymer used. It is to provide a fillene-based composite material and a method for producing the same.
[0011]
[Means for Solving the Problems]
A first invention of the present application is 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 organic layered silicate, Further containing 0.5 to 10 parts by weight of a crystal nucleating agent, An average interlayer distance of the organically modified layered silicate detected by X-ray diffraction measurement after holding the polyolefin composite material at a temperature of the melting point of the polyolefin resin + 40 ° C. or higher is 6 nm or more.
[0012]
A second invention is 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, Further containing 0.5 to 10 parts by weight of a crystal nucleating agent, After the polyolefin composite material is held at a temperature equal to or higher than the melting point of the polyolefin resin + 40 ° C., the increase rate before and after holding the number of particles having a major axis of 3 μm or more is 50% or less.
[0013]
First and second departure In the light Further contains 0.5 to 10 parts by weight of a crystal nucleating agent, whereby the precipitation of polyolefin crystals is suppressed, and the dispersibility of the organically modified layered silicate is maintained well. Preferably, as the crystal nucleating agent, a rosin crystal nucleating agent or a sorbitol crystal nucleating agent is used, and the dispersion state of the organically modified layered silicate is more favorably maintained.
[0016]
In the polyolefin-based composite materials according to the first and second inventions, a swellable smectite-based viscosity mineral / or swellable mica is preferably used as the layered silicate for constituting the organically modified layered silicate.
[0017]
The polyolefin resin is preferably an ethylene homopolymer, a copolymer of ethylene and α-olefin, an ethylene-propylene copolymer, a propylene homopolymer, and a copolymer of propylene and α-olefin. At least one of the coalescence is used.
[0018]
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, the polyolefin resin is 100 weights, the organically modified layered silicate is 0.1 to 50 parts by weight, the crystal nucleating agent is 0.5 to 10 parts by weight, and the melt kneading. By doing so, a polyolefin-based composite material is obtained.
[0019]
Ma Book In still another aspect of the production method of the invention, the organically modified layered silicate is chemically bonded to the polyolefin resin at a temperature not higher than the melting point of the polyolefin resin.
[0020]
Details of the present invention will be described below.
In the present invention, the layered silicate means a silicate mineral having a plurality of layers composed of many fine flaky crystals and having exchangeable cations between the layers. The flaky crystal usually has a thickness of 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.
[0021]
The type of layered silicate having an exchangeable cation between the layers is not particularly limited. For example, smectite clay minerals such as montmorillonite, saponite, hectorite, beidellite, stevensite, nontronite; vermiculite, halloysite, etc. Natural mica, or synthetic mica such as swellable mica (swelling mica), which may be natural or synthesized. Preferably, a swellable smectite clay mineral or swellable mica is used.
[0022]
Two or more of the above layered silicates may be used in combination.
In addition, the lamellar silicate has the function of increasing the gas barrier property of the composite material by the flaky crystals acting as partition walls. Therefore, the higher the aspect ratio of the lamellar crystal of the layered silicate, the higher the gas barrier property. Therefore, montmorillonite having an aspect ratio of about 100 and swellable mica having an aspect ratio of about 150 are preferably used in applications where gas barrier properties are required.
[0023]
The structure of the lamellar silicate crystal flakes is schematically shown in FIG. FIG. 2 is a schematic view 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. This exchangeable cation is generally sodium ion or calcium ion on the crystal surface (B). Since these ions have ion exchange properties with a cationic substance, various substances having a cationic property can be inserted between the layers.
[0024]
In the present invention, organic layered silicate is used. Organized layered silicate refers to those in which the layer of layered silicate is ion-exchanged by a chemical species having a hydrophobic group. The organic layered silicate has a high affinity for polyolefin resins, which are nonpolar resins, because the layers are hydrophobized.
[0025]
Hydrophobization between layers is performed by ion exchange of exchangeable cations existing between layers of the layered silicate with a cationic surfactant.
In general, 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 exchanged with the exchangeable cations of the cationic surfactant. It has ion exchange properties. Accordingly, various cationic surfactants having exchangeable cations can be inserted between the layers.
[0026]
Therefore, by using a cationic surfactant having a low polarity, the above-mentioned exchangeable cation is ion-exchanged with the exchangeable ion of the cationic surfactant, so that the crystal surface of the layered silicate becomes nonpolar or has a low polarity. The dispersibility of the layered silicate in the nonpolar resin can be enhanced.
[0027]
As described above, the exchangeable cation is usually an ion of an alkali metal or an alkaline earth metal such as sodium or calcium, and the exchangeable cation is lower than the exchangeable cation. Equivalent ions are used.
[0028]
In addition, when using ion equivalent to an exchangeable cation, the density | concentration of an exchangeable cation should just be higher than the density | concentration of an exchangeable cation.
The cationic surfactant is not particularly limited, and a commonly used cationic surfactant is used, and examples thereof include quaternary ammonium salts, quaternary phosphonium salts, and the like as main components. A quaternary ammonium salt having an alkyl chain having 8 or more carbon atoms is used. When the alkyl chain having 8 or more carbon atoms is not included, the alkyl group ammonium ion has strong hydrophilicity, and it becomes difficult to sufficiently non-polarize or lower the polarity of the layered silicate layer.
[0029]
Examples of the quaternary ammonium salt include lauryl trimethyl ammonium salt, stearyl trimethyl ammonium salt, trioctyl ammonium salt, distearyl dimethyl ammonium salt, di-cured tallow dimethyl ammonium salt, distearyl dibenzyl ammonium salt and the like.
[0030]
The cation exchange capacity of the layered silicate is not particularly limited. However, if the amount is too small, the amount of the cationic surfactant intercalated by the ion exchange between the crystal layers is small, so the layers may not be sufficiently hydrophobized. 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 the crystal flakes (delamination), and therefore it is preferably 50 to 200 meq / 100 g.
[0031]
Moreover, in the polyolefin-type composite material which concerns on this invention, an organic layered silicate is used in 0.1-50 weight part with respect to 100 weight part of polyolefin-type resin. 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 become hard and brittle is increased in physical properties, and the moldability and appearance are impaired. .
[0032]
The polyolefin resin used in the present invention is not particularly limited, and is a homopolymer of ethylene, propylene or α-olefin; a copolymer of ethylene and propylene, a copolymer of ethylene and α-olefin, propylene and α-olefin. Examples include olefin copolymers, copolymers of two or more α-olefins, and the like. Examples of the α-olefin include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene and the like.
[0033]
Moreover, these polyolefin resin may be used independently and may be used in mixture of 2 or more types.
The molecular weight and molecular weight distribution of the polyolefin resin are not particularly limited, and the weight average molecular weight is preferably 5,000 to 5,000,000, more preferably 20,000 to 300,000. The molecular weight distribution (weight average molecular weight Mw / number average molecular weight Mn) is preferably 2 to 80, more preferably 3 to 40.
[0034]
The polyolefin resin may be appropriately alloyed or blended with other types of polymer compounds. For example, a small amount of a polymer compound grafted with carboxylic acid such as maleic acid may be added to increase the affinity between the polyolefin resin and the layered silicate in advance.
[0035]
The average interlayer distance detected by X-ray diffraction measurement of the organically modified layered silicate in the polyolefin-based composite material according to the present invention is preferably 6 nm or more. In general, the strengthening of a polymer by an inorganic material is performed more efficiently as the area of the polymer / inorganic interface is larger. Therefore, when the layered silicate is agglomerated with each other by ionic bonding force, that is, at an interlayer distance of about 1 to 2 nm, the modification effect by adding the layered silicate is very small. Only after the lamellar 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. In general, the interlayer attractive force of the layered silicate becomes extremely small when the interlayer is peeled off to 6 nm or more, so it is important to set the average interlayer distance to 6 nm or more.
[0036]
The interlayer distance defined in the present invention refers to the distance between the 001 planes of the lamellar silicate flaky crystals, that is, the distance between the centers of the two flaky crystals in FIG. Further, the average interlayer distance defined in the present invention is calculated by obtaining the distance between flaky crystals and the amount of silicate in the distance between flaky crystals by X-ray diffraction. Two typical examples are shown below. FIG. 3 is an X-ray diffraction profile when the average interlayer distance is 6 nm or more, and FIG. 4 is an X-ray diffraction profile when the average interlayer distance is less than 6 nm. That is, in FIG. 3, a small diffraction peak is observed at an interlayer distance of 2 nm, but most of the interlayer distance can be confirmed by a broad diffraction line of 6 nm or more.
[0037]
As described above, even when the flaky crystals of the layered silicate are sufficiently dispersed in the composite material, the composite material is again maintained at a temperature equal to or higher than the melting point of the polyolefin resin and further solidified as described above. Thus, agglomerated particles are formed by agglomeration of lamellar crystals of layered silicate.
[0038]
In the polyolefin-based composite material according to the present invention, even when the remelting treatment is performed in this manner, the dispersion state of the lamellar crystals of the layered silicate is maintained well, and the generation of the aggregated particles can be effectively suppressed. it can.
This will be described in more detail below. The reason why the dispersibility of the layered silicate is impaired during the above heat treatment is considered as follows.
[0039]
(1) Polyolefins are inherently very hydrophobic and are essentially incompatible with substances having a hydrophilic surface, such as layered silicates. In the present invention, by making the layered silicate organic, the affinity with the polyolefin is enhanced. However, since the layered silicate locally leaves a hydrophilic surface, it is agglomerated between the layered silicates. There is a tendency to try.
[0040]
(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 excluded by this crystal growth and aggregates at the crystal interface.
[0041]
Therefore, the inventors of the present application have found that if a crystal nucleating agent is added, the precipitation of giant crystals can be suppressed, and thereby the dispersion state of the layered silicate can be maintained well.
[0042]
The crystal nucleating agent is not particularly limited, but a soluble crystal nucleating agent such as a rosin crystal nucleating agent such as a rosin acid partial metal salt or a crystal nucleating agent represented by a dibenzylidene sorbitol compound is preferably used. It is possible.
[0043]
Dibenzylidene sorbitol compounds include dibenzylidene sorbitol, bis (dimethylbenzylidene) sorbitol, bis (diethylbenzylidene) sorbitol, bis (dipropylbenzylidene) sorbitol, bis (dibutylbenzylidene) sorbitol, bis (hexylbenzylidene) sorbitol, bis (di Chlorobenzylidene) sorbitol and the like, and these may be used alone or in combination.
[0044]
As commercially available crystal nucleating agents, rosin-based crystal nucleating agents such as KM1500 and KM1300 (manufactured by Arakawa Chemical Co., Ltd.), EC1, EC1-55, EC-4 (manufactured by EC Chemical Co., Ltd.), Gelall MD, Gelall D, Examples thereof include dibenzylidene sorbitol-based crystal nucleating agents such as gel all MD-R, gel all DH, gel all T (manufactured by Shin Nippon Rika)
[0045]
Among them, the rosin-based crystal nucleating agent tends to give a polymer crystal nucleus to the surface of the layered silicate because the metal or hydrophilic group in the structure has a strong affinity with the local hydrophilic portion of the layered silicate. That is, the crystal growth of the polymer proceeds preferentially on the surface of the layered silicate, and the elimination of the layered silicate and the aggregation at the crystal interface due to the crystal growth are suppressed. Therefore, even when the molten composite material is solidified again, the dispersion state of the lamellar crystals of the layered silicate is maintained well.
[0057]
【Example】
EXAMPLES Next, although an Example and a comparative example are given and this invention is demonstrated in detail, this invention is not limited only to these Examples.
The raw materials used in the following examples and comparative examples will be described.
A: Raw materials used
[0058]
(1) Layered silicate
The following minerals were used as the layered silicate.
・ Montmorillonite: Montmorillonite manufactured by Toyshun Mining Co., Ltd.
-Swellable mica: Swelled mica manufactured by Co-op Chemical (trade name; ME-100)
[0059]
(2) Organized layered silicate
As the organic layered silicate, the following commercially available product containing a cationic surfactant between layers was used.
・ DSDM-modified montmorillonite:
DSDM modified montmorillonite manufactured by Toyshun Mining Co., Ltd. (trade name; organic montmorillonite obtained by ion exchange of all sodium ions between montmorillonite layers with New Sven D = distereal dimethylammonium chloride)
・ DSDM-modified swelling mica:
DSDM modified swellable mica manufactured by Coop Chemical (trade name; MAE = organized swellable mica obtained by ion exchange of all sodium ions between montmorillonite layers with distearyldimethylammonium chloride)
[0060]
(3) Vinyltrimethoxysilane-treated montmorillonite
While stirring DSDM-modified montmorillonite manufactured by Toyshun Mining in a Henschel mixer, 2% by weight of vinyltrimethoxysilane (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise to the solid content.
[0061]
(4) Polyolefin resin
The following commercial products were used as polyolefin resins.
·polypropylene:
(Nippon Polychem, trade name; EA9, density 0.91, MFR = 0.5)
·polyethylene:
(Nippon Polychem, trade name; HB530, density 0.96, MFR = 0.5)
・ Silane modified polyethylene
(Nippon Polychem, trade name; Linkron, density 0.94, MFR = 2.1)
[0062]
(5) Acid-modified polyolefin resin
In order to increase the affinity between the polyolefin resin and the layered silicate, the following commercial products were used.
-Maleic anhydride modified polypropylene oligomer:
(Product name: Sanyo Chemicals Co., Ltd .; Umex 1001, Functional group content = 0.23 mmol / g)
-Maleic anhydride modified polyethylene oligomer:
(Trade name: Sanyo Chemical Co., Ltd .; Umex 2000, functional group content = 0.92 mmol / g)
[0063]
(6) Crystal nucleating agent
The following commercially available products were used as crystal nucleating agents.
・ Rosin crystal nucleating agent
(Arakawa Chemicals product name: KM1500)
・ Sorbitol crystal nucleating agent
(New Nippon Rika product name: Gelall MD)
[0064]
(7) Polyethylene polymerization reagent
The following commercially available products were used as reagents for polymerizing polyethylene.
・ Dicyclopentadienyl titanium dichloride (Aldrich)
・ Methylalmonoxan (Aldrich)
[0065]
(8) Crosslinking aid
The following commercially available products were used as crosslinking aids.
・ Trimethylpentatriacrylate
(Product name made by Nippon Oil &Fats; 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 the same as the method described in JP-A-10-182892.
[0066]
(1) (Examples 1-5, 11 and Comparative Examples 1-4, Comparative Example 9)
In Laboplast mill manufactured by Toyo Seiki, polypropylene resin (Nippon Polychem, trade name: EA9, density 0.91, MFR = 0.5), polyethylene resin (Nippon Polychem, trade name: HB530, density 0.96, MFR = 0.5), silane-modified polyethylene resin (Nippon Polychem, trade name; Linkron, density 0.94, MFR = 2.1), polyethylene resin or silane-modified polyethylene resin, and maleic anhydride-modified polypropylene oligomer (manufactured by Sanyo Kasei) Trade name: Umex 1001, functional group content = 0.23 mmol / g), or maleic anhydride-modified polyethylene oligomer (trade name; Umex 2000, functional group content = 0.92 mmol / g) and Coop Chemical DSDM modified puffed mica (trade name: MAE) or Toyshun Mining OS M-modified montmorillonite (trade name: New S. Ben D) and, as shown in Table 1 below, was fed at a rate of 80/5/10 by weight. As required, as shown in Table 1 below, the desired crystal nucleating agent was supplied in the amount shown in Table 1 below. N at a set temperature of 200 ° C ₂ It was melt-kneaded for 10 minutes in a gas atmosphere. The obtained composite material composition is taken out in a molten state and quickly charged into a mold, and 100 kg / cm ² While pressing the mold contents for 1 minute, the mold was rapidly cooled to room temperature to form a 1 mm thick sheet.
[0067]
(2) (Example) 6 and And Comparative Examples 5, 7, 8, 10)
A polyolefin resin and an organically modified layered silicate shown in Table 1 below were fed at a ratio of 95/5 by weight in a Toyo Seiki Laboplast mill, and melt kneaded at a preset temperature of 200 ° C. for 10 minutes.
[0068]
The obtained composite composition was preheated at 200 ° C. for 5 minutes in a melt press, and 100 kg / cm for 1 minute. ² Was pressed to form a 1 mm thick sheet. A 1 mm thick sheet was cut into a 3 cm square, sealed in an autoclave, and the internal temperature of the autoclave was set to a temperature 10 ° C. higher than the melting point or glass transition temperature of the polyolefin resin. Next, carbon dioxide or nitrogen gas is injected into the autoclave at a high pressure, and the internal pressure in the autoclave is 170 kg / cm. ² Was held for 30 minutes. Furthermore, the temperature in the autoclave was set to a temperature lower by 10 ° C. than the melting point or glass transition temperature of the polyolefin resin, and in this state, the gas in the autoclave was exhausted at once, and the internal pressure was returned to normal pressure to obtain a foamed body.
[0069]
(3) (Example 7, Comparative Example 6)
300 ml of distilled toluene was introduced into four 500 ml flasks, and 0.5 g of organically modified layered silicate was added. After stirring at room temperature for 1 hour and confirming the transparency of the mixed slurry, the surroundings of the slurry were replaced with nitrogen to block contact with the outside air. Furthermore, 0.05 g of methylammonoxane was added to the mixed slurry, and the mixture was stirred for 15 minutes. A solution in which 0.02 g of dicyclopentadienyl dichloride was previously dissolved in 100 ml of toluene was added to the slurry, and ethylene gas was immediately fed.
[0070]
After the reaction was continued for 3 hours, the contents of the flask were taken out, reprecipitated with methanol and repeatedly washed, and then the solid matter was taken out by filtration.
C: Crosslinking method
Of the samples obtained as described above, as shown in Table 1. Compared to For Comparative Example 7, the following crosslinking treatment was performed as necessary.
[0071]
(1) Electron beam crosslinking
A sample subjected to electron beam crosslinking and electron beam irradiation was cut into a thickness of 1 mm, and irradiated with a 1 Mrad electron beam by an electron irradiation apparatus manufactured by Nissin High Voltage.
[0072]
(2) Hydrothermal crosslinking
A sample to be subjected to hot-water crosslinking was cut out to a thickness of 1 mm and placed in a thermostatic chamber whose temperature was adjusted to 100 ° C. Subsequently, 100 degreeC water vapor | steam was introduce | transduced in the thermostat, and the pressure in a thermostat was set to 1.2 atmospheres. After the treatment for 5 hours, a sample was taken out.
D: Evaluation method
The sample obtained as described above and the sample subjected to post-treatment were evaluated in the following manner. The results are shown in Table 2.
[0075]
(2) Change in aggregation state by heat treatment
The sample obtained by the above method was cut into a thickness of 30 μm by a microtome, and the number of particles having a long piece of 3 μm or more in a 3 mm square field of view was counted by an optical microscope. The sample is held for 5 minutes at a temperature of the melting point of the sample + 40 ° C. by a hot stage placed on the sample stage of the same optical microscope. At this time, particles having a long piece of 3 μm or more in a 3 mm square field of view. I counted the number.
[0076]
(3) Flexural modulus
A test piece was cut out from a 1 mm thick plate-like material obtained by the above method, maintained at a temperature of the melting point of the polyolefin resin + 40 ° C. for 5 minutes, solidified again, and then in a method defined in JISK7207, The flexural modulus was measured using a Tensilon tester.
[0077]
Sample obtained by layered silicate dispersion method (2) (Example) 6 and And Comparative Examples 5, 7, 8, and 10) were not evaluated because the sample had a foam shape.
[0078]
(4) Oxygen permeability
A test piece was cut out from the 100 μm thick plate obtained by the above method, maintained at a temperature of the melting point of the polyolefin resin + 40 ° C. for 5 minutes, and then solidified again, and then an oxygen permeability tester (Modern Control Co., Ltd.). The oxygen gas permeation rate was measured with the apparatus name “Oxtran-Twin”.
[0079]
Sample obtained by layered silicate dispersion method (2) (Example) 6 and And Comparative Examples 5, 7, 8, and 10) were not evaluated because the sample had a foam shape.
[0080]
(5) Layer distance of layered silicate
After maintaining for 5 minutes at the melting point of polyolefin resin + 40 ° C. and solidifying again, it is obtained from diffraction of the layered surface of the layered silicate in the composite by an X-ray diffraction measurement device (Rigaku; RINT1100) ( The 2θ of the (100) plane was measured, and the plane spacing of the layered silicate was calculated using the black diffraction formula (3).
[0081]
λ = 2 dsin θ (3)
(Λ = 1.54, d: interplanar spacing of layered silicate, θ: diffraction angle)
D obtained from the equation (3) is referred to as an average interlayer distance.
E: Evaluation result
Tables 1 and 2 show the details and evaluation results of the blends of Examples and Comparative Examples.
[0082]
[Table 1]
[0083]
[Table 2]
[0084]
(1) Effects of adding a crystal nucleating agent
From the comparison of Examples 1 to 7 and Comparative Examples 1, 2, 4, and 5, it can be seen that any of the crystal nucleating agents has a remarkable effect in suppressing the generation of aggregates in the composite material by heat treatment. As shown in Table 2, the major axis is 3 μm when 0.1 to 10 parts by weight of the crystal nucleating agent is added when any polymer, organic layered silicate, additive, or dispersion method is used. While the increase in the above particles was 50% or less, when the crystal nucleating agent was not added, a marked increase in aggregated particles was confirmed. The decrease in flexural modulus and oxygen permeability with increasing aggregated particles is evident from Table 2.
Further, as shown in Comparative Example 3, when the crystal nucleating agent is added in an excessive amount of 11% by weight, the effect of modifying the elastic modulus and oxygen permeability is lowered.
[0087]
【Effect of the invention】
In the polyolefin-based composite material according to the present invention, 0.1 to 50 parts by weight of the organic layered silicate is blended with respect to 100 parts by weight of the polyolefin-based resin, Further containing 0.5 to 10 parts by weight of a crystal nucleating agent, Since the average interlayer distance of the organically modified layered silicate detected by X-ray diffraction measurement is 6 nm or more after holding at a temperature of the melting point of the polyolefin resin + 40 ° C. or higher, or the number of particles having a major axis of 3 μm or more is maintained. Since the increase ratio before and after is 50% or less, even when the dispersion state of the flaky crystals in the organic layered silicate is remelted, it is maintained well. Therefore, by using the polyolefin-based composite material according to the present invention and the method for producing the composite material, modification of the polyolefin-based resin with layered silicate, that is, improvement in elastic modulus, increase in heat distortion temperature, gas barrier property Not only can the improvement and improvement of flame retardancy, the polyolefin composite material according to the present invention exhibits the above various effects well even when used as a masterbatch or remelted when reused. To do. Therefore, the industrial utility value of the polyolefin-based composite material can be significantly increased.
[Brief description of the drawings]
FIG. 1 is a schematic view showing the structure of a lamellar silicate crystal flake.
2 is an enlarged schematic view showing a cubic portion X of the crystal structure shown in FIG. 1. 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 an X-ray diffraction profile of a layered silicate having an average interlayer distance of less than 6 nm.
FIG. 5 is a schematic diagram of an optical micrograph before heat treatment of a conventional polyolefin-based composite material.
FIG. 6 is a schematic diagram of an optical micrograph after heat treatment of a conventional polyolefin-based composite material.
[Explanation of symbols]
1 ... Layered silicate
B ... Crystal surface

Claims (6)

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,
Further containing 0.5 to 10 parts by weight of a crystal nucleating agent,
A polyolefin having an average interlaminar distance of 6 nm or more of the organically modified layered silicate detected by X-ray diffraction measurement after holding the polyolefin composite material at a temperature of the melting point of the polyolefin resin + 40 ° C. or higher. Based composite materials. 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,
Further containing 0.5 to 10 parts by weight of a crystal nucleating agent,
The polyolefin-based resin is characterized in that, after the polyolefin-based composite material is held at a temperature of the melting point of the polyolefin-based resin + 40 ° C. or higher, the increasing ratio before and after holding the number of particles having a major axis of 3 μm or more is 50% or less. Composite material. The polyolefin composite material according to claim 1 or 2, wherein the crystal nucleating agent is a rosin crystal nucleating agent or a sorbitol crystal nucleating agent. The polyolefin composite material according to any one of claims 1 to 3, wherein the layered silicate is a swellable smectite viscosity mineral and / or swellable mica. The polyolefin resin is at least one of an ethylene homopolymer, a copolymer of ethylene and an α-olefin, an ethylene-propylene copolymer, a propylene homopolymer, and a copolymer of propylene and an α-olefin. The polyolefin-type composite material in any one of Claims 1-4. It is a manufacturing method of the polyolefin-type composite material of Claim 1 or 2, Comprising: 100 weight part of polyolefin-type resin, 0.1-50 weight part of organic-ized layered silicate, and 0.5-10 weight of crystal nucleating agent A method for producing a polyolefin-based composite material, comprising melt-kneading a part.