JP2022145083A - Propylene polymer composition and foam - Google Patents

Abstract

To provide a propylene-based foam having a high expansion ratio and excellent impact resistance.SOLUTION: There is provided a propylene polymer composition, comprising: two or more propylene polymer components; and an ethylene-α-olefin copolymer (3) which has a melt flow rate of less than 10 g/10 min measured at a temperature of 190°C and a load of 2.16 kg, a density of 850 to 910 kg/m3, and contains an ethylene monomer unit and an α-olefin monomer unit having 3 to 8 carbon atoms. The propylene polymer composition has a melt flow rate of 12 to 23 g/10 min measured at a temperature of 230°C and a load of 2.16 kg and satisfies the following formula (1). MT≥7.52×MFR(-0.576) +1...(1). (where MT represents the melt tension (g) measured at a temperature of 190°C and a take-up speed of 15.7 m/min; and MFR indicates the melt flow rate (g/10 min) measured at a temperature of 230°C and a load of 2.16 kg.).SELECTED DRAWING: None

Description

This invention relates to propylene polymer compositions and foams.

Propylene foams are used for packaging, shipping boxes, partition plates, food containers, stationery, building materials, automobile interior materials, and the like.

In Cited Document 1, in a propylene-based resin multilayer foam sheet having a resin layer and a resin layer on the surface of the propylene-based resin foam layer obtained by a co-extrusion method using a T-die, the foam layer, the resin layer and the resin The layer has a melt tension (MT(190)) at 190°C and a melt flow rate (MFR(230)) at 230°C such that MT(190)≧7.52×MFR(230) ^(−0.576) . A multi-layer foamed sheet made of a propylene-based resin containing a satisfactory linear propylene-based polymer in an amount of 10% by mass or more is disclosed.

JP 2004-291626 A

In the multi-layered foam sheet as described above, there is a high need for further increasing the expansion ratio, which leads to weight reduction and cost reduction. However, there is still room for improvement in that increasing the expansion ratio of the foam causes a decrease in the impact resistance of the foam.

An object of the present invention is to provide a propylene-based foam having a high expansion ratio and excellent impact resistance.

In order to solve the above problems, two or more propylene polymer components according to one aspect of the present invention and a melt flow rate measured at a temperature of 190° C. and a load of 2.16 kg are less than 10 g/10 minutes, An ethylene-α-olefin copolymer (3) having a density of 850 to 910 kg/m ³ and containing ethylene monomer units and α-olefin monomer units having 3 to 8 carbon atoms, A propylene polymer composition having a melt flow rate of 12 to 23 g/10 minutes measured at a temperature of 230° C. and a load of 2.16 kg, and satisfying the following formula (1): MT≧7.52×MFR ^(−0.576) +1 (1)
(In the formula, MT is the melt tension (g) measured at a temperature of 190°C and a take-up speed of 15.7 m/min. MFR is the melt flow rate (g) measured at a temperature of 230°C and a load of 2.16 kg. /10 minutes).)

According to one aspect of the present invention, it is possible to provide a propylene polymer composition that provides a propylene-based foam having a high expansion ratio and excellent impact resistance, and a foam thereof.

[Propylene polymer composition]
Hereinafter, the propylene polymer composition according to one embodiment of the present invention will be described in detail. A propylene polymer composition according to one embodiment contains two or more propylene polymer components and an ethylene-α-olefin copolymer (3), and has a melt measured at a temperature of 230°C and a load of 2.16 kg. It has a flow rate of 12 to 23 g/10 minutes and satisfies the following formula (1).

MT≧7.52×MFR ^(-0.576) +1 (1)
(In the formula, MT is the melt tension (g) measured at a temperature of 190°C and a take-up speed of 15.7 m/min. MFR is the melt flow rate (g) measured at a temperature of 230°C and a load of 2.16 kg. /10 minutes).)

Melt tension is evaluated as tension applied to the molten resin when the molten resin extruded from the cylinder is drawn. Melt tension can be measured using a melt tension measuring machine. Specifically, the melted propylene polymer composition is drawn through a pulley equipped with a load cell at a predetermined speed by a take-up roller, and the load (g) applied to the pulley at this time is measured by the load cell. . Melt tension is evaluated under the conditions of a melting temperature of 190° C. with a cylinder.

Melt tension is a parameter that determines the degree of hardness when the propylene polymer composition is melt-deformed, and affects cell growth when producing a foam from the propylene polymer composition. For example, a propylene polymer composition can be melted inside an extruder, mixed with a foaming gas, melt extruded through a die, and taken off by a take-off roll to form a foam. Here, the propylene polymer composition extruded from the die can be taken up by a take-up roll while being cooled. At this time, the propylene polymer composition may be stretched to form a foam while bubbles are formed therein by the foaming gas.

The propylene polymer composition that satisfies the above formula (1) has a melt flow rate (MFR) within a predetermined range, so that it is suitable inside the propylene polymer composition at the initial stage of cell growth during foam production. Air bubbles can be generated. In addition, since the propylene polymer composition satisfies the above formula (1) in terms of melt tension measured at a high take-up speed of 15.7 m/min, the cells do not grow excessively at the final stage of cell growth during foam production. , the occurrence of air bubble breakage can be suitably prevented.

Although not limited, the MT is preferably 2.2 to 6.0 g, more preferably 2.3 to 4.5 g.

The propylene polymer composition according to one embodiment has a melt flow rate of 12 to 23 g/10 minutes, more preferably 14 to 22 g/10 minutes, measured at a temperature of 230° C. and a load of 2.16 kg. The propylene polymer composition according to one embodiment has a melt flow rate measured at a temperature of 230° C. and a load of 2.16 kg in the range of 14.0 to 30.0 g/10 minutes, and the above formula (1) is By satisfying the conditions, it is possible to obtain a propylene polymer composition from which a propylene foam having good foamability and excellent impact resistance can be obtained. Hereinafter, the propylene foam may be simply referred to as "foam".

The "expansion ratio" is a measurement method using a water substitution method, and the density of the foam is determined, and the density of the foam is divided by the density of the unfoamed propylene polymer composition. refers to The higher the expansion ratio, the better the foamability.

The "impact resistance" of a foam can be evaluated by the DuPont impact test specified in JIS K5600-5-3:1999.

(Melt tension ratio)
In one embodiment, the melt tension ratio is, as shown in the following formula (1), the ratio of the melt tension when the propylene polymer composition is taken at a take-up speed of 28.3 m/min and at a take-up speed of 3.2 m/min. It is a ratio.

The propylene polymer composition according to one embodiment may have a melt tension ratio of less than 1.7 calculated by the following formula (2).

MT ^R =MT ¹ /MT ² (2)
(In the formula, MT ^R indicates the melt tension ratio of the propylene polymer composition. MT ¹ indicates the melt tension (g) of the propylene polymer composition measured at a take-up speed of 28.3 m/min. MT ² indicates the melt tension (g) of the propylene polymer composition measured at a take-up speed of 3.2 m/min.)

A propylene polymer composition according to one embodiment may meet the requirements of formula (1) above and have a melt tension ratio as defined in formula (2) of less than 1.7. Due to the action of the ethylene-α-olefin copolymer (3), the propylene polymer composition according to one embodiment is a foam even if the melt tension ratio defined in formula (2) is less than 1.7. A propylene polymer composition can be obtained in which cell growth can be suitably controlled during the production of , and a high expansion ratio can be achieved. Further, by containing the ethylene-α-olefin copolymer (3), the foam can be imparted with high impact resistance.

The melt tension ratio of the propylene polymer composition according to one embodiment is preferably 1.1 or more, more preferably 1.2 or more.

[Components contained in the propylene polymer composition]
(Ethylene-α-olefin copolymer (3))
The ethylene-α-olefin copolymer (3) contained in the propylene polymer composition according to one embodiment is ethylene containing ethylene monomer units and α-olefin monomer units having 3 to 8 carbon atoms. - α-olefin copolymer. Further, the ethylene-α-olefin copolymer (3) preferably has a melt flow rate of less than 10 g/10 minutes, more preferably less than 9 g/10 minutes, measured at a temperature of 190°C and a load of 2.16 kg. preferable. It is preferable that the density is 850-910 kg/m ³ .

Such an ethylene-α-olefin copolymer (3) has the effect of suitably suppressing cell growth in the final stage of cell growth when a foam is produced by injecting gas into the propylene polymer composition. . Therefore, it is possible to prevent breakage of cell walls during foam production. Further, by including the ethylene-α-olefin copolymer (3) defined as described above, a foam having a high magnification ratio is produced using the propylene polymer composition according to one embodiment. can also improve impact resistance. From this point of view, the ethylene-α-olefin copolymer (3) preferably has a melt flow rate of less than 10 g/10 minutes, preferably less than 9 g/10 minutes, measured at a temperature of 190° C. and a load of 2.16 kg. is preferably The ethylene-α-olefin copolymer (3) has a melt flow rate of less than 10 g/10 minutes measured at a temperature of 190° C. and a load of 2.16 kg. Growth can be suitably suppressed. The propylene polymer composition satisfies the requirements of formula (1) and contains an ethylene-α-olefin copolymer (3) having a predetermined melt flow rate, thereby achieving a high expansion ratio and high impact resistance. Foams can be produced that combine two properties that seemingly can be traded off.

Examples of α-olefins include α-olefins having 4 to 10 carbon atoms, and examples of α-olefins having 4 to 10 carbon atoms include 1-butene, 1-pentene, 1-hexene, 4-methyl -1-pentene, 1-octene, 1-decene, 3-methyl-1-butene, etc., preferably α-olefins having 4 to 10 carbon atoms, more preferably 1-butene, 1- hexene or 1-octene.

Specific examples of the ethylene-α-olefin copolymer (3) include ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer, and ethylene-1-decene copolymer. It is an ethylene-(3-methyl-1-butene) copolymer, and these may be a single type or a mixture of two or more types. Also, the ethylene polymer (3) may be a mixture of an ethylene homopolymer and a copolymer of ethylene and α-olefin.

The ethylene-α-olefin copolymer (3) can be produced by a known polymerization method using a known polymerization catalyst.

Polymerization catalysts include, for example, homogeneous catalyst systems represented by metallocene catalysts, Ziegler-type catalyst systems, Ziegler-Natta-type catalyst systems, and the like. The homogeneous catalyst system includes, for example, a catalyst system comprising a transition metal compound of Group 4 of the periodic table having a cyclopentadienyl ring and an alkylaluminoxane, and a transition metal compound of Group 4 of the periodic table having a cyclopentadienyl ring. A catalyst system consisting of a compound that reacts with it to form an ionic complex and an organoaluminum compound, a transition metal compound of Group 4 of the periodic table having a cyclopentadienyl ring in inorganic particles such as silica and clay minerals, an ionic Examples thereof include a catalyst system in which a catalyst component such as a compound forming a complex and an organoaluminum compound is loaded and modified. Also included are prepolymerized catalyst systems prepared by prepolymerizing ethylene and α-olefins in the presence of the above catalyst systems.

(Propylene polymer material (1))
The propylene polymer material (1) contains two or more propylene polymer components. Here, the two or more propylene polymer components can be propylene polymer components (11) and (12). These propylene polymer components (11) and (12) are preferably contained in the propylene polymer composition as components of the propylene polymer material (1). More preferably, the propylene polymer composition contains a propylene polymer material (2).

The propylene polymer material (1) preferably has a melt flow rate of 2 to 11 g/10 minutes measured at a temperature of 230° C. and a load of 2.16 kg. When the melt flow rate of the propylene polymer material (1) is within the above range, the propylene resin can be sufficiently stretched and deformed in the production process of the propylene foam. When the melt flow rate of the propylene polymer material (1) is within this range, the propylene resin composition can be sufficiently elongated and deformed in the process of producing a foam from the propylene polymer composition. Further, by making the melt flow rate of the propylene polymerization material (1) smaller with reference to the range, the melt tension shown in the formula (1) can be increased.

The propylene polymerization component (11) preferably has an intrinsic viscosity of 6 to 15 dL/g, more preferably 6.5 to 8.0 dL/g. Propylene polymer component (12) preferably has an intrinsic viscosity of 0.5 to 1.3 dL/g, more preferably 0.5 to 1.0 dL/g. When the intrinsic viscosities of the propylene polymer components (11) and (12) are within the above range, the melt flow rate of the propylene polymer component (1) is within a suitable range. Also, with reference to the ranges of the intrinsic viscosities of the propylene polymer components (11) and (12) contained in the propylene polymer material (1), the intrinsic viscosity of the propylene polymer component (11) is increased and propylene The melt tension of the propylene polymer composition with respect to the melt flow rate shown in formula (1) can be increased by either or both of decreasing the intrinsic viscosity of the polymer component (12). In addition, the melt tension ratio of the propylene polymer composition shown in formula (2) can be made higher.

The content of the propylene polymer component (11) is 6 to 25% by mass with respect to the total 100% by mass of the content of the propylene polymer component (11) and the content of the propylene polymer component (12). It is preferably 12 to 22% by mass, and the content of the propylene polymer component (12) is preferably 75 to 94% by mass, more preferably 78 to 88% by mass. preferable.

The propylene polymerized material (1) is preferably obtained by continuously polymerizing the propylene polymer component (11) and the propylene polymer component (12). In that case, the propylene polymerized material (1) and the propylene polymer component ( The intrinsic viscosity of 11) can be measured in tetralin (1,2,3,4-tetrahydronaphthalene) at 135° C. using an Ubbelohde viscometer.

The intrinsic viscosity of the propylene polymer component (12) is calculated by the following formula ( 2) can be used for calculation.

[η] ₁₂ = ([η] ₁ ×100−[η] ₁₁ ×W ₁₁ )/W ₁₂ (2)
(In the formula, [η] ₁₂ represents the intrinsic viscosity (dl/g) of the propylene polymer component (12). [η] ₁ represents the intrinsic viscosity (dl/g) of the propylene polymerization material (1). [η] ₁₁ represents the intrinsic viscosity (dl/g) of the propylene polymer component (11), W ₁₁ represents the content (% by mass) of the propylene polymer component (11), and W ₁₂ represents the Shows the content (% by mass) of the propylene polymer component (12).)

The propylene polymer components (11) and (12) contained in the propylene polymer material (1) can each be a crystalline propylene polymer component having a polypropylene crystal structure, a homopolymer of propylene, or propylene and Copolymers with comonomers such as ethylene and/or α-olefins in amounts that do not lose crystallinity are preferred, and are preferably linear. Examples of α-olefins are α-olefins having 4 to 10 carbon atoms, and examples of α-olefins having 4 to 10 carbon atoms include 1-butene, 1-pentene, 1-hexene, 4-methyl-1 -pentene, 1-octene, 1-decene, 3-methyl-1-butene, etc., preferably α-olefins having 4 to 10 carbon atoms, more preferably 1-butene, 1-hexene or 1-octene. The amount that does not lose crystallinity varies depending on the type of comonomer. , the amount of α-olefin units in the copolymer is usually 30% by mass or less. The propylene polymer components (11) and (12) may have the same composition or different compositions. Also, some of the propylene polymer components (11) and (12) may be block-bonded. Furthermore, even if the propylene polymer components (11) and (12) are block-bonded together with the other propylene polymer components (11) and (12) in the propylene polymer material (1), good.

The content of the propylene polymer component (11), the content of the propylene polymer component (12), and the content of the ethylene-α-olefin copolymer (3) in total of 100% by mass, propylene The content of polymer component (11) is preferably 5 to 20% by mass, more preferably 9 to 18% by mass, and the content of propylene polymer component (12) is 45 to 88% by mass. is preferably 48 to 75% by mass, and the content of the ethylene-α-olefin copolymer (3) is preferably 7 to 40% by mass, preferably 20 to 40% by mass. is more preferable. By keeping the contents of the propylene polymer components (11) and (12) within the above range, the melt flow rate of the propylene polymer component (1) can be within a suitable range. Moreover, the impact resistance of the foam produced from the propylene polymer composition can be favorably improved. Further, referring to the above content ranges, the higher the content of the propylene polymer component (11) and the propylene polymer component (12), the higher the melt tension. The smaller the content of the polymer (3), the higher the melt tension of the propylene polymer composition.

(Propylene polymer material (2))
The propylene polymer composition of one embodiment further comprises a propylene polymerized material (2) comprising one or more propylene polymer components. The propylene polymer material (2) preferably has a melt flow rate of 50 g/10 minutes or more, more preferably 70 g/10 minutes or more, measured at a temperature of 230° C. and a load of 2.16 kg.

By including propylene polymer materials (1) and (2) having different melt flow rates, a sufficient melt tension ratio can be imparted to the propylene polymer composition according to one embodiment. It is presumed that this is because the polymer material (2) having a high melt flow rate does not hinder the elongational deformation of the propylene polymer material (1) having a low melt flow rate. Here, the propylene polymer material (2) has a melt flow rate of 50 g/10 minutes or more measured at a temperature of 230° C. and a load of 2.16 kg. While imparting a melt tension ratio, it can contribute to lowering the melt tension during low-speed (3.2 m/min) take-up of the propylene polymer composition.

The propylene polymer material (2) is not particularly limited as long as the melt flow rate is within the range described above. Examples of propylene polymeric material (2) are similar to examples of propylene polymeric material (1), for example propylene homopolymers and copolymers of propylene with comonomers such as ethylene and/or α-olefins. mentioned. Examples of the α-olefin include those similar to the propylene polymerization material (1).

The content of the propylene polymer component (11), the content of the propylene polymer component (12), the content of the propylene polymerization material (2), and the content of the ethylene-α-olefin copolymer (3) The content of the propylene polymer component (11) is preferably 5 to 17% by mass, more preferably 5.5 to 10% by mass, based on the total of 100% by mass. The content of the propylene polymer component (12) is preferably 24-63% by mass, more preferably 25-45% by mass. The content of the propylene polymerization material (2) is preferably 25-54% by mass, more preferably 28-52% by mass. The content of the ethylene-α-olefin copolymer (3) is preferably 7-25% by mass, more preferably 10-23% by mass. By setting the propylene polymer component (11), the propylene polymer component (12), the propylene polymer material (2) and the ethylene-α-olefin copolymer (3) within the above range, the melt flow rate is high. A propylene polymer composition is obtained which exhibits melt tension, ie satisfies the above formula (1). Also, the larger the content of the ethylene-α-olefin copolymer (3), the higher the impact resistance of the foam when the foam having a high expansion ratio is produced.

When the contents of the propylene polymer components (11) and (12), the propylene polymer material (2), and the ethylene-α-olefin copolymer (3) are within the above ranges, cell growth during foam production is suppressed. It can be suitably controlled. Furthermore, when a foam is produced using the propylene polymer composition of one embodiment, the foam can have sufficient impact resistance.

[Foam]
A foam according to one embodiment comprises the propylene polymer composition according to one embodiment of the invention described above.

A propylene polymer composition according to one embodiment may include a blowing agent. The foaming agent is not particularly limited, and known foaming agents can be used. For example, physical foaming agents include carbon dioxide gas, nitrogen gas, air, propane, butane, pentane, hexane, dichloroethane, dichlorodifluoromethane, dichloromonofluoromethane, and trichloromonofluoromethane. Nitrogen gas, carbon dioxide gas, It is preferable to use a safe and environment-friendly inorganic gas such as air, and it is more preferable to use carbon dioxide gas because of its high solubility in propylene-based resins. When carbon dioxide gas is used, it is preferable to mix it with the propylene-based resin in a supercritical state at 7.4 MPa or higher and 31° C. or higher from the viewpoint of diffusion into the resin and solubility.

Examples of chemical blowing agents include baking soda, mixtures of baking soda with citric acid, sodium citrate, stearic acid and other organic acids, isocyanate compounds such as azodicarbonamide, tolylene diisocyanate, 4,4' diphenylmethane diisocyanate, azobis butyronitrile, barium azodicarboxylate, diazoaminobenzene, azo and diazo compounds such as trihydrazinotriazine, benzene sulfonyl hydrazide, P,P'-oxybis(benzenesulfonyl hydrazide), toluene sulfonyl hydrazide Hydrazine derivatives such as N,N'-dinitroso pentamethylene tetramine, N,N'-dimethyl-N,N'-dinitroso terephthalamide and other nitroso compounds, P-toluene sulfonyl semicarbazide, 4,4' In addition to semicarbazide compounds such as oxybisbenzenesulfonyl semicarbazide, azide compounds and triazole compounds can be mentioned. Baking soda, citric acid, or azodicarbonamide are particularly preferred.

The above physical foaming agents and chemical foaming agents may be used alone, or two or more of them may be used in combination. Further, when a chemical foaming agent is used, a foaming aid may be used together in order to adjust the decomposition temperature and decomposition rate. For example, since azodicarbonamide alone has a decomposition temperature as high as about 200° C., a small amount of zinc oxide, zinc stearate, urea, or the like may be added as a foaming aid when processing at a low temperature is desired.

When using a physical blowing agent, a cell nucleating agent can be added. Cell nucleating agents include talc, silica, diatomaceous earth, calcium carbonate, magnesium carbonate, barium sulfate, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, calcium silicate, zeolite, mica, clay, wollastonite, and hydrotalcite. , magnesium oxide, zinc oxide, zinc stearate, calcium stearate, polymer beads such as PMMA, synthetic aluminosilicates, and the chemical blowing agents mentioned above.

(Other ingredients)
The propylene polymer composition of one embodiment may optionally contain various additives. For example, on the surface of the propylene polymer composition, additives and/or modified resins for expressing functions according to applications such as packaging, shipping boxes, partition plates, food containers, stationery, building materials, and automotive interior materials. is preferably included. Such additives and/or modifying resins include antistatic agents, flame retardants, fillers, antioxidants, copper damage inhibitors, weathering agents, UV absorbers, lubricants, pigments, blowing agents, and the like. be done.

[Foam]
A foam according to one embodiment of the present invention comprises a propylene polymer composition according to one embodiment of the present invention as described above. The foam according to one embodiment is not particularly limited as long as it has the propylene polymer composition according to one embodiment of the present invention. For example, the foam has an arbitrary resin layer on the surface of the propylene polymer composition. It may be a multilayer foam.

The expansion ratio and thickness of the propylene foam according to one embodiment are not particularly limited, but the expansion ratio is 4 times or more. When the propylene foam according to one embodiment is used as a foam sheet, the thickness of the entire sheet may be 1-7 mm. Since the expansion ratio of the foam and the thickness of the sheet are within the above ranges, the propylene foam according to one embodiment can be suitably used as a thin foam sheet.

(Method for manufacturing foam)
A propylene polymer composition of one embodiment is obtained by a co-extrusion method using a T-die. The propylene polymer composition and the foaming agent are melt-kneaded using an extruder, laminated and integrated in a feed block or T-die connected to the extruder, and co-extruded into the atmosphere to obtain a flat molten sheet. The flat molten sheet is brought into contact with a large number of rolls which are placed immediately after the multi-layer T die and whose cooling temperature is controlled, or is passed between two plate-like flat plates whose cooling temperature is controlled while being in contact with each other. After cooling by the known method of No. 1, it is taken by a take-up machine equipped with nip rolls and cut into a predetermined size by a cutter to produce a propylene polymer composition foamed sheet.

As an extruder, a single-screw extruder or a multi-screw extruder can be used, and a tandem extruder combining a plurality of extruders can also be used. As an extruder used for kneading the propylene polymer composition and the foaming agent, a twin-screw extruder is preferable. It is more preferable to use an extruder with a structure that generates less shear heat. A cooling medium may be circulated through the screw body to control the temperature.

A gear pump is provided between each extruder and the feed block or multi-layer T die, and a constant feeder is provided for raw material supply, and the gear pump inlet pressure is constantly controlled by feedback to the rotation speed of the screw or gear pump or the raw material supply amount. A system that does this is also effective in stabilizing the state of extrusion foaming.

It is also effective to stabilize the foaming state by inserting a static mixer or the like into the adapter connecting each extruder and the feed block or multilayer T-die to make the resin temperature uniform.

When using a physical blowing agent, the extruder for the propylene polymer composition has a structure that allows the blowing agent to be injected into the molten resin. It is necessary that the foaming agent and the foaming agent are sufficiently mixed and homogenized so that the resin temperature can be controlled appropriately for foaming.

The surface of the propylene foam according to one embodiment can be subjected to surface treatment such as corona treatment, ozone treatment, and application of an antistatic agent, if necessary. A skin material such as a sheet or a film may be laminated on one or both sides of the propylene foam according to the embodiment according to the application to obtain a skin material-laminated propylene foam. The propylene foam and skin-laminated propylene foam of one embodiment can also be subjected to thermoforming such as vacuum forming.

When laminating an arbitrary layer on the foam, known skin materials such as sheets or films for lamination can be used depending on the application. Examples include metals such as aluminum and iron, thermoplastic resins, Examples include thin plates made of paper, synthetic paper, and the like. A non-woven fabric or a woven fabric made of a plant material such as a thermoplastic resin or hemp or an inorganic material such as glass may be laminated. Moreover, decoration such as embossing or printing may be applied to the surface of the thin plate to be used. A foam may be used as a skin material for lamination.

For example, when the foam of one embodiment is used for food packaging, it is preferable to laminate a propylene-based resin film or a gas barrier resin film having a thickness of 10 to 100 μm. Ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polyvinyl alcohol, polyamide and the like can be used as the gas barrier resin. These gas barrier resins may be used singly or in combination, or two or more types of gas barrier resin films may be laminated for use.

When the foam of one embodiment is used for automotive interior materials, it is preferred to laminate non-woven fabrics, woven fabrics, carpets, and the like. In other packaging applications, for example, when used as a partition plate for a box, a cushioning sheet may be laminated to protect the contents.

The method of laminating the skin material to the propylene foam according to one embodiment is not particularly limited. A method of heating and melting the surface of an adhesive resin film using a material and laminating it with propylene foam, a method of melting and laminating the surface of the skin material and foam using a heater or hot air, etc. A method of laminating by extrusion lamination between the material and the foam sheet can be used.

A propylene foam according to one embodiment can be used for packaging, shipping boxes, partition plates, food containers, stationery, building materials, automobile interior materials, and the like.

The present invention is not limited to the above-described embodiments, but can be modified in various ways within the scope of the claims, and can be obtained by appropriately combining technical means disclosed in different embodiments. is also included in the technical scope of the present invention.

〔summary〕
A propylene polymer composition according to an embodiment of the present invention comprises two or more propylene polymer components, a melt flow rate of less than 10 g/10 minutes measured at a temperature of 190° C. under a load of 2.16 kg, and a density of is 850 to 910 kg/m ³ and contains an ethylene-α-olefin copolymer (3) containing ethylene monomer units and α-olefin monomer units having 3 to 8 carbon atoms; The melt flow rate measured at 230° C. under a load of 2.16 kg is 12 to 23 g/10 minutes, satisfying the following formula (1).

MT≧7.52×MFR ^(-0.576) +1 (1)
(In the formula, MT is the melt tension (g) measured at a temperature of 190°C and a take-up speed of 15.7 m/min. MFR is the melt flow rate (g) measured at a temperature of 230°C and a load of 2.16 kg. /10 minutes).)

With this configuration, when a foam is produced using the propylene polymer of one embodiment, it is possible to obtain a foam having good foamability and excellent impact resistance.

Further, in the propylene polymer composition according to one embodiment of the present invention, the propylene polymer composition contains a propylene polymer material (1), and the propylene polymer material (1) has an intrinsic viscosity of 6 to 15 dL/g. and a propylene polymer component (12) having a limiting viscosity of 0.5 to 1.3 dL/g. It has a melt flow rate of 2-11 g/10 min measured at 0.16 kg.

When the intrinsic viscosities of the propylene polymer components (11) and (12) are within this range, the melt flow rate of the propylene polymer material (1) is within a preferred range. Further, by setting the melt flow rate of the propylene polymer material (1) within the above range, the propylene resin can be sufficiently elongated and deformed in the production process of the propylene foam.

Further, the propylene polymer composition according to one embodiment of the present invention comprises the content of the propylene polymer component (11), the content of the propylene polymer component (12), and the ethylene-α-olefin copolymer. The content of the propylene polymer component (11) is 5 to 20% by mass and the content of the propylene polymer component (12) is 45% by mass based on the total 100% by mass of the content of the polymer (3) and 88% by mass, and the content of the ethylene-α-olefin copolymer (3) is 7 to 40% by mass. With this configuration, the melt flow rate of the propylene polymer composition is within the preferred range.

Further, the propylene polymer composition according to one embodiment of the present invention contains one or more propylene polymer components and has a melt flow rate of 50 g/10 minutes or more measured at a temperature of 230° C. and a load of 2.16 kg. Contains a propylene polymerized material (2). With this configuration, a suitable melt flow rate can be imparted to the propylene polymer composition according to one embodiment.

Further, the propylene polymer composition according to one embodiment of the present invention comprises the content of the propylene polymer component (11), the content of the propylene polymer component (12), and the propylene polymer material (2). and the content of the ethylene-α-olefin copolymer (3) totaling 100% by mass, the content of the propylene polymer component (11) is 5 to 17% by mass, and the propylene weight The content of the combined component (12) is 24-63% by mass, the content of the propylene polymerization material (2) is 25-54% by mass, and the content of the ethylene-α-olefin copolymer (3) is 7 to 25% by mass. With this configuration, it is possible to obtain a propylene polymer composition capable of suitably controlling cell growth during foam production and imparting sufficient impact resistance to the foam.

Further, the propylene polymer composition according to one embodiment of the present invention has a melt tension ratio of less than 1.7 calculated by the following formula (2).

MT ^R =MT ¹ /MT ² (2)
(In the formula, MT ^R indicates the melt tension ratio of the propylene polymer composition. MT ¹ indicates the melt tension (g) of the propylene polymer composition measured at a take-up speed of 28.3 m/min. MT ² indicates the melt tension (g) of the propylene polymer composition measured at a take-up speed of 3.2 m/min.)

A foam according to an embodiment of the invention also comprises a propylene polymer composition according to an embodiment of the invention.

EXAMPLES The present invention will be described below using Examples and Comparative Examples, but the present invention is not limited to these Examples.

(1) Melt flow rate (MFR, unit: g/10 minutes)
According to the method specified in JIS K-7210:1999, the melt flow rate of the propylene polymer composition or propylene polymer material was measured under conditions of a temperature of 230° C. or 190° C. and a load of 2.16 kg.

The melt flow rate measured under the conditions of a temperature of 230° C. and a load of 2.16 kg is described as “MFR (230° C.)”, and the melt flow rate measured under the conditions of a temperature of 190° C. and a load of 2.16 kg is referred to as “MFR ( 190°C)”.

(2) Melt tension (MT)
Melt tension tester type 2 (manufactured by Toyo Seiki Co., Ltd.) was used to measure the melt tension of the propylene polymer composition under the following conditions, and the melt tension ratio was calculated.

A cylinder with an inner diameter of 9.55 mm was fitted with an orifice with a length of 8.00 mm and an inner diameter of 2.10 mm. After that, the cylinder was filled with the propylene polymer composition, inserted with a piston, and preheated at 190° C. for 5 minutes to sufficiently melt the propylene polymer composition. Thereafter, the piston is lowered at a speed of 5.7 mm/min, and the propylene polymer composition melted and extruded from the orifice is drawn through the pulley at 15.7 m/min, and the load (g) applied to the pulley is measured with a load cell. and melt tension.

(3) Melt tension ratio (MT ratio)
Using a melt tension measuring machine manufactured by Toyo Seiki Co., Ltd., the melt tension of the propylene polymer composition was measured under the following conditions.

A cylinder with an inner diameter of 9.55 mm was fitted with an orifice with a length of 8.00 mm and an inner diameter of 2.10 mm. After that, the cylinder was filled with the propylene polymer composition, inserted with a piston, and preheated at 190° C. for 5 minutes to sufficiently melt the propylene polymer composition. After that, the piston is lowered at a speed of 5.7 mm/min, and the propylene polymer composition melted and extruded from the orifice is drawn through the pulley at a speed of 3.2 m/min or 28.3 m/min, and a load balanced with the pulley is applied. The weight (g) was measured with a load cell and taken as the melt tension.

The melt tension ratio was calculated using the following formula (2).

MT ^R =MT ¹ /MT ² (2)
(In the formula, MT ^R indicates the melt tension ratio of the propylene polymer composition. MT ¹ indicates the melt tension (g) of the propylene polymer composition measured at a take-up speed of 28.3 m/min. MT ² indicates the melt tension (g) of the propylene polymer composition measured at a take-up speed of 3.2 m/min.)
(4) Intrinsic viscosity The intrinsic viscosity of the propylene polymer component (11) and the propylene polymerization material (1) was measured in tetralin (1,2,3,4-tetrahydronaphthalene) at 135°C using an Ubbelohde viscometer. .

The intrinsic viscosity of the propylene polymer component (12) is calculated by the following formula (3) from the intrinsic viscosity of the propylene polymer component (11) and the propylene polymer material (1) and the masses of the propylene polymer components (11) and (12). was calculated using

[η] ₁₂ = ([η] ₁ ×100−[η] ₁₁ ×W ₁₁ )/W ₁₂ (3)
(In the formula, [η] ₁₂ represents the intrinsic viscosity (dl/g) of the propylene polymer component (12). [η] ₁ represents the intrinsic viscosity (dl/g) of the propylene polymerization material (1). [η] ₁₁ represents the intrinsic viscosity (dl/g) of the propylene polymer component (11), W ₁₁ represents the content (% by mass) of the propylene polymer component (11), and W ₁₂ represents the Shows the content (% by mass) of the propylene polymer component (12).)

(5) Expansion Ratio The density of the foam was obtained by a measurement method using a water substitution method. The expansion ratio was calculated by dividing the density of the foam by the density of the unfoamed propylene polymer composition. The higher the expansion ratio, the better the foamability. A foam with little gas escape and an expansion ratio of 4 times or more was judged to have good foamability.

(6) Impact resistance of foam The impact resistance of foam was evaluated by the DuPont impact test specified in JIS K5600-5-3. After adjusting the temperature of the foam test piece (70 mm×70 mm) to −10° C., an impact test was performed 10 times under the conditions of a drop load of 300 g and a drop height of 40 cm. When the ratio of cracks and/or cracks in the foam was 60% or more, it was judged that the impact resistance was good. Note that the impact resistance test was performed only on sheets with good foamability.

(7) Production of propylene polymer material (1-1) Propylene was homopolymerized by the method disclosed in JP-A-11-228629 to produce a propylene polymer powder. The propylene polymer powder contains a propylene polymer component (11-1) with an intrinsic viscosity of 7.0 dl/g and a propylene polymer component (12-1) with an intrinsic viscosity of 0.8 dl/g. Met. The mass ratio of the propylene polymer component (11-1) and the propylene polymer component (12-1) was 19% by mass:81% by mass, and the propylene polymer powder had an intrinsic viscosity of 1.9 dl/g. there were.

100 parts by mass of propylene polymer powder, 0.05 parts by mass of calcium stearate, 0.10 parts by mass of trade name Irganox (registered trademark) 1010 (manufactured by BASF Japan Ltd.), and trade name of Irgafos (registered trademark) 168 ( (manufactured by BASF Japan Ltd.) and melt-kneaded at 230° C. to obtain pellets of propylene polymerization material (1-1) having an MFR (230° C.) of 7.7 g/10 min. rice field.

(8) Propylene polymer material (2)
(8-1) Propylene polymerization material (2-1)
As the propylene polymerization material (2-1), a mixture of a propylene homopolymer component and an ethylene-propylene copolymer component obtained by homopolymerizing propylene and then copolymerizing ethylene and propylene (Sumitomo Chemical Co., Ltd. Company Noblen (registered trademark), grade: AU161C, MFR (230°C) = 90 g/10 min, ethylene-propylene copolymer content = 11% by mass) was used. "Noblen" is a registered trademark of Sumitomo Chemical Co., Ltd.

(8-2) Propylene polymerization material (2-2)
As the propylene polymerization material (2-2), a mixture of a propylene homopolymer component and an ethylene-propylene copolymer component obtained by homopolymerizing propylene and then copolymerizing ethylene and propylene (Sumitomo Chemical Co., Ltd. Company Noblen, grade: AW161C, MFR (230°C) = 9 g/10 min, ethylene-propylene copolymer content = 14% by mass) was used.

(8-3) Propylene polymerized material (2-3)
As the propylene polymerization material (2-3), a mixture of a propylene homopolymer component and an ethylene-propylene copolymer component obtained by homopolymerizing propylene and then copolymerizing ethylene and propylene (Sumitomo Chemical Co., Ltd. Company Noblen, grade: AZ564, MFR (230° C.)=30 g/10 min, ethylene-propylene copolymer content=13% by mass) was used.

(9) Ethylene-α-olefin copolymer (3)
(9-1) Ethylene-α-olefin copolymer (3-1)
As the ethylene-α-olefin copolymer (3-1), Tafmer (registered trademark) DF740 (manufactured by Mitsui Chemicals, Inc., ethylene-1-butene copolymer, MFR (190° C.) = 3.2 g/10 min, density = 870 kg/m ³ ) was used.

(9-2) Ethylene-α-olefin copolymer (3-2)
As the ethylene-α-olefin copolymer (3-2), Excellen (registered trademark) FX402 (manufactured by Sumitomo Chemical Co., Ltd., ethylene-1-hexene copolymer, MFR (190° C.) = 8 g/10 min, density = 880 kg/m ³ ) was used. "Excellen" is a registered trademark of Sumitomo Chemical Co., Ltd.

(9-3) Ethylene-α-olefin copolymer (3-3)
As the ethylene-α-olefin copolymer (3-3), Sumikasen E FV401 (manufactured by Sumitomo Chemical Co., Ltd., ethylene-1-hexene copolymer, MFR (190 ° C.) = 4 g / 10 minutes, density = 903 kg / m ³ ) was used. "Sumikasen" is a registered trademark of Sumitomo Chemical Co., Ltd.

(9-4) Ethylene-α-olefin copolymer (3-4)
As the ethylene-α-olefin copolymer (3-4), Tafmer (registered trademark) DF8200 (manufactured by Mitsui Chemicals, Inc., ethylene-1-butene copolymer, MFR (190° C.) = 18 g/10 min, density = 885 kg/m ³ ) was used.

[Example 1]
48% by mass of the propylene polymerized material (1-1), 32% by mass of the propylene polymerized material (2-1), and 20% by mass of the ethylene-α-olefin copolymer (3-1) are melt-kneaded to obtain propylene. A polymer composition was obtained.

100 parts by mass of the obtained propylene polymer composition and 0.3 parts by mass of a cell nucleating agent (masterbatch containing azodicarbonamide, Cellmic MB1023, manufactured by Sankyo Kasei) were mixed. The resulting mixture was charged into the extruder hopper shown below.

A 50mmΦ single-screw extruder (L/D = 42, L is the effective length of the screw, D is the diameter of the screw) equipped with a gear pump at the tip, and a T-die with a resin channel width of 100mm and a thickness of 1.3mm at the lip part. extruder connected with.

In order to obtain a foam by carbon dioxide physical foaming, liquefied carbon dioxide is injected at a high pressure of 105 g/h with a diaphragm type metering pump at the position where the mixture has melted, and the mixture is further melted and kneaded to melt and foam. A sexual mixture was obtained. The resulting molten mixture was introduced into the T-die while adjusting the gear pump so that the discharge amount showed 12.6 kg / h, and then the molten mixture discharged from the T-die was discharged at a speed of 2.2 m / min. to obtain a foam containing a propylene polymer composition.

The temperature of each portion of the extruder was adjusted within the range of 170°C to 190°C so that the resin thermometer attached to the tip of the extruder indicated 180°C. The temperatures of the gear pump section and the T-die section were adjusted to 180°C. The extruder speed was adjusted so that the resin pressure at the gear pump inlet was 7 MPa.

[Example 2]
48% by mass of propylene polymerized material (1-1), 32% by mass of propylene polymerized material (2-1), and 20% by mass of ethylene-α-olefin copolymer (3-2) are melt-kneaded to obtain propylene polymer. A foam was obtained in the same manner as in Example 1, except that a combined composition was obtained.

[Example 3]
32% by mass of the propylene polymerized material (1-1), 48% by mass of the propylene polymerized material (2-1), and 20% by mass of the ethylene-α-olefin copolymer (3-1) are melt-kneaded to obtain propylene. A foam was obtained in the same manner as in Example 1, except that a polymer composition was obtained.

[Comparative Example 1]
Propylene polymerization material (1-1) 50% by mass, propylene polymerization material (2-2) 40% by mass, and ethylene-α-olefin copolymer (3-3) 10% by mass are melt-kneaded to obtain propylene. A foam was obtained in the same manner as in Example 1, except that a polymer composition was obtained.

[Comparative Example 2]
In the same manner as in Example 1, except that 80% by mass of the propylene polymerized material (1-1) and 20% by mass of the propylene polymerized material (2-3) were melt-kneaded to obtain a propylene polymer composition. A foam was obtained.

[Comparative Example 3]
32% by mass of propylene polymerized material (1-1), 48% by mass of propylene polymerized material (2-1), and 20% by mass of ethylene-α-olefin copolymer (3-4) are melt-kneaded to obtain propylene. A foam was obtained in the same manner as in Example 1, except that a polymer composition was obtained.

The components of the propylene polymer compositions of Examples 1-3 and Comparative Examples 1-4 are shown in Table 1. Also, the MFR of the propylene polymer compositions of Examples 1 to 3 and Comparative Examples 1 to 4, the value on the left side of formula (1), the value on the right side of formula (1), whether the formula (1) is satisfied, and melt tension ratio are shown in Table 2. If the formula (1) is satisfied, it is indicated by "O", and if it is not satisfied, it is indicated by "x". Furthermore, Table 3 shows the expansion ratio and impact resistance measurement results.

INDUSTRIAL APPLICABILITY The present invention can be applied to propylene foams that can be used for packaging, shipping boxes, partition plates, food containers, stationery, building materials, automobile interior materials, and the like.

Claims (7)

two or more propylene polymer components;
It has a melt flow rate of less than 10 g/10 minutes measured at a temperature of 190 ° C. and a load of 2.16 kg, a density of 850 to 910 kg / m ³ , and an ethylene monomer unit and an α- and an ethylene-α-olefin copolymer (3) containing olefin monomer units,
The melt flow rate measured at a temperature of 230 ° C. and a load of 2.16 kg is 12 to 23 g / 10 minutes,
A propylene polymer composition satisfying the following formula (1).
MT≧7.52×MFR ^(-0.576) +1 (1)
(In the formula,
MT indicates the melt tension (g) measured at a temperature of 190°C and a take-up speed of 15.7 m/min.
MFR indicates the melt flow rate (g/10 min) measured at a temperature of 230°C and a load of 2.16 kg. ) comprising a propylene polymerized material (1);
The propylene polymer material (1) contains a propylene polymer component (11) and a propylene polymer component (12) as the two or more propylene polymer components,
The propylene polymer component (11) has an intrinsic viscosity of 6 to 15 dL/g,
The propylene polymer component (12) has an intrinsic viscosity of 0.5 to 1.3 dL/g,
The propylene polymer composition according to claim 1, wherein the propylene polymer material (1) has a melt flow rate of 2 to 11 g/10 minutes measured at a temperature of 230°C and a load of 2.16 kg. Based on the total 100% by mass of the content of the propylene polymer component (11), the content of the propylene polymer component (12), and the content of the ethylene-α-olefin copolymer (3) hand,
The content of the propylene polymer component (11) is 5 to 20% by mass,
The content of the propylene polymer component (12) is 45 to 88% by mass,
3. The propylene polymer composition according to claim 2, wherein the content of the ethylene-α-olefin copolymer (3) is 7-40% by mass. Claims 1 to 1 further comprising a propylene polymer material (2) containing at least one propylene polymer component and having a melt flow rate of 50 g/10 minutes or more measured at a temperature of 230°C under a load of 2.16 kg. 4. The propylene polymer composition according to any one of 3. The content of the propylene polymer component (11), the content of the propylene polymer component (12), the content of the propylene polymer material (2), and the ethylene-α-olefin copolymer (3) With respect to the total 100% by mass of the content of
The content of the propylene polymer component (11) is 5 to 17% by mass,
The content of the propylene polymer component (12) is 24 to 63% by mass,
The content of the propylene polymerization material (2) is 25 to 54% by mass,
5. The propylene polymer composition according to claim 4, wherein the content of the ethylene-α-olefin copolymer (3) is 7-25% by mass. The propylene polymer composition according to any one of claims 1 to 5, wherein the melt tension ratio calculated by the following formula (2) is less than 1.7.
MT ^R =MT ¹ /MT ² (2)
(In the formula,
^MTR indicates the melt tension ratio of the propylene polymer composition.
MT ¹ indicates the melt tension (g) of the propylene polymer composition measured at a take-up speed of 28.3 m/min.
MT ² indicates the melt tension (g) of the propylene polymer composition measured at a take-up speed of 3.2 m/min. ) A foam containing the propylene polymer composition according to any one of claims 1-6.