JP2015187232A - polyolefin foam sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foamed body using a polyolefin-based resin which has both excellent moldability and flexibility, satisfies an increased required performance and is especially suitably used in applications of an automobile interior material requiring molding into a complicated shape and flexibility after molding.SOLUTION: There is provided a polyolefin foam sheet which comprises 15 pts.mass or more and 75 pts.mass or less of an olefin-based block copolymer (A) having a melting point of 115°C or more and a melt index (hereinafter defined as MI) of 0.1 to 40 g/10 min (190°C) and 85 pts.mass or more and 25 pts.mass or less of a polypropylene-based resin (B) having an MI of 0.1 to 25 g/10 min (230°C) and has a gel fraction of 20 to 75% and a density of 25 to 250 kg/m.

Description

  The present invention relates to a molded article using a polyolefin-based resin crosslinked foamed sheet that is excellent in a balance of physical properties such as mechanical strength, heat resistance, flexibility and elongation, and can be molded into a complicated shape.

  Conventionally, a crosslinked foamed sheet made of a polyolefin-based resin is widely used as a vehicle interior material such as a ceiling, a door, and an instrument panel because it is excellent in flexibility, heat resistance, mechanical strength, and the like.

  For these applications, there has often been a demand for flexible foams. For example, in the case of a door panel of an automobile, a comfortable cushioning property cannot be obtained if a hard foam is used for an armrest portion.

  As such a polyolefin foam sheet, for example, Patent Document 1 discloses polyethylene and / or ethylene copolymer, ethylene-butene-propylene copolymer A having a melting point of 130 to 160 ° C., and copolymer A. A polyolefin system characterized by adding a foaming agent, a crosslinking agent and / or a crosslinking accelerator to a mixture of polypropylene and / or a propylene copolymer having a melting point of 10 ° C. or more higher than the melting point, and crosslinking and foaming. A method for producing a resin crosslinked foamed sheet is disclosed.

  However, the polyolefin foam sheet obtained by the production method disclosed in the above publication has a problem that the flexibility is insufficient, and tearing occurs when the polyolefin-based resin cross-linked foam sheet is molded into a complicated shape. There was a problem.

Furthermore, Patent Document 2 discloses that 25% compressive strength at normal temperature is 4.9 to 11.8 N / cm ² , 100% modulus at 120 ° C. is 15.7 to 29.4 N / cm ² , and 100% modulus at 160 ° C. Is a polyolefin-based resin-crosslinked foamed sheet characterized by a 3.9 to 9.8 N / cm ² and a specific gravity of 0.04 to 0.20.

  However, the polyolefin foam sheet disclosed in the above publication has a problem that heat resistance is insufficient in molding into a molded product having a complicated shape which has been increasing in recent years.

Japanese Patent Publication No. 2-38100 JP 2000-355085 A

  The object of the present invention is to provide a polyolefin resin foam sheet that is excellent in the balance of physical properties such as mechanical strength, heat resistance, flexibility and elongation, and can obtain a molded product having a complicated shape using a molding method such as vacuum molding. There is to do.

The present invention for solving the above-mentioned problems is as follows.
1) 15 to 75 parts by mass of an olefin block copolymer (A) having a melting point of 115 ° C. or higher and a melt index (hereinafter referred to as MI) of 0.1 to 40 g / 10 min (190 ° C.),
85 parts by mass or more and 25 parts by mass or less of a polypropylene resin (B) having an MI of 0.1 to 25 g / 10 min (230 ° C.),
The gel fraction is 20-75%,
A polyolefin foam sheet characterized by having a density of 25 to 250 kg / m ³ .

  According to the polyolefin foam sheet of the present invention, the polyolefin foam has excellent physical property balance such as mechanical strength, heat resistance, flexibility and elongation, and can obtain a molded product having a complicated shape using a molding method such as vacuum molding. Sheets can be provided.

  The polyolefin-based block copolymer (A) used in the present invention includes a multi-block polymer having a large number of blocks including a hard block having a relatively high crystallinity and a soft block having a lower crystallinity than the hard block. be able to. A multi-block polymer (eg, a multi-block olefin-based polymer) is a homopolymer containing one α-olefin monomer or a copolymer containing two α-olefin monomers or a terpolymer containing three or more monomers (typically Can include at least two monomers that are α-olefins, and can even include three α-olefins), or can include four or more α-olefin monomers. it can. Multiblock homopolymers can include hard and soft blocks containing the same monomer, the difference between these blocks being the regularity of the monomers (eg, hard blocks are monomers that are regularly oriented rather than soft blocks) The hard block has a higher degree of crystallinity). The olefinic block copolymer (A) can comprise blocks having different concentrations of monomers. For example, the olefinic block copolymer (A) has a high concentration (eg, greater than about 80%, preferably greater than about 90%, more preferably greater than about 95%, most preferably about 99% by weight of the olefinic block copolymer). One or more hard blocks comprising more than or even 100% by weight of a first α-olein-based monomer and a low concentration of a second α-olefin-based monomer; It can have one or more soft blocks containing a lower concentration of the first α-olefin than the block. Preferably, the first α-olefin is a lower α-olefin (LOA) which is ethylene or propylene, and thus the olefinic block copolymer is a LOA / α-olefin interpolymer. Without limitation, the olefinic block copolymer (A) can be an ethylene / α-olefin interpolymer or a propylene / α-olefin interpolymer. In the polyolefin block copolymer (A), the α-olefin repeating unit is 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene. , 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-itethene, the repeating unit can be derived from one or more α-olefins selected from the group consisting of

  The polyolefin block copolymer (A) used in the present invention preferably has a melt index (MI (190 ° C.)) at 190 ° C. of 0.1 to 40 g / 10 min (190 ° C.), more preferably 0.5. ˜30 g / 10 min. If MI (190 ° C.) is less than 0.1 g / 10 min, the load on the machine during kneading may be excessive and may not be processed. If MI (190 ° C.) exceeds 40 g / 10 min, the mechanical strength of the foam may be increased. May be insufficient as a product.

  The polyolefin block copolymer (A) used in the present invention preferably has a melting endothermic peak temperature (melting point) by differential scanning calorimetry of 115 ° C. or higher, more preferably 118 ° C. or higher. Especially preferably, it is 120 degreeC or more and 124 degrees C or less.

  The olefin block copolymer (A) used in the present invention preferably has a hardness of 25 degrees or more and 80 degrees or less using a type A durometer based on JIS K6235. More preferably, they are 30 degree | times or more and 70 degrees or less, More preferably, they are 50 degree | times or more and 70 degrees or less. If the numerical value is lower than 25 degrees, there is no “stiffness” when the foam is made, and there is a possibility that the handling when placing the foam in the molding machine may be deteriorated. If the numerical value is higher than 80 degrees, it depends on the amount of addition. This is because it becomes difficult to obtain a polyolefin-based foamed sheet having sufficient flexibility, which is an object of the present invention.

Examples of the polypropylene resin (B) used in the present invention include a propylene homopolymer, a copolymer of propylene and a polymerizable monomer containing 50% by mass or more of propylene, and the like. Polypropylene resins may be used alone or in combination of two or more. Examples of polymerizable monomers copolymerizable with prolene include α-olefins such as ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene and 1-octene. Is mentioned. The polymerizable monomer copolymerizable with propylene may be used alone or in combination of two or more.

  Such a polypropylene resin (B) is particularly preferably a propylene homopolymer and / or a propylene-olefin copolymer.

  The melt index (MI) at 230 ° C. of these polypropylene resins (B) is measured under normal conditions of a temperature of 230 ° C. and a load of 2.16 kgf based on JIS K7210 (1999). It is preferable that MI (230 degreeC) of the polypropylene resin (A) used exists in the range of 0.1-25 g / 10min (230 degreeC).

  If the MI is less than 0.1 g / 10 min, the thermal decomposable foaming agent may be decomposed by shearing to form a sheet, which may cause problems in appearance, and if the MI exceeds 25 g / 10 min, Heat resistance may be insufficient. The MI of the polypropylene resin (B) is more preferably 1.0 to 10 g / min, and still more preferably 1.7 to 2.5 g / min.

  In general, MI has a strong correlation with the molecular weight. When the molecular weight is large, the MI value decreases, and conversely, when the molecular weight is small, the MI value increases. However, the value varies depending on the copolymerization ratio, molecular weight distribution, etc., and thus cannot be defined unconditionally.

  The polypropylene resin (B) used in the present invention has a melting endothermic peak temperature of 137 ° C. or higher and 168 ° C. or lower, more preferably 137 ° C. or higher and 150 ° C. or lower, as determined by differential scanning calorimetry. Especially preferably, it is 146 degreeC or more and 148 degrees C or less.

  The endothermic peak as used herein refers to an endothermic reaction that occurs when a crystalline polymer crystal melts, measured by a differential scanning calorimeter, and generally treated as a melting point. If this endothermic peak is high, it can be said that the higher the endothermic peak is, the more difficult it is to melt and the higher the heat resistance. The polyolefin foamed sheet used in the present invention is a polyolefin foamed sheet comprising 15 to 75 parts by mass of the polyolefin block copolymer (A) and 85 to 25 parts by mass of the polypropylene resin (B). Preferably, the polyolefin block copolymer (A) is contained in an amount of 15 to 50 parts by mass, and the polypropylene resin (B) is contained in an amount of 85 to 50 parts by mass. When the polyolefin block copolymer (A) is less than 15 parts by mass, the desired flexibility cannot be obtained, and when it is more than 75 parts by mass, the heat resistance is insufficient and the molding processability is deteriorated.

If the (expanded) density of the polyolefin foam sheet is small, the heat resistance becomes insufficient, and bubbles (cells) are destroyed during thermoforming. If it is large, the flexibility and elongation of the polyolefin foam sheet are insufficient. Therefore, 25 to 250 kg / m ³ is preferable.
In addition, the apparent density of a polyolefin foamed sheet says what was measured based on JISK6767 "foamed plastic-polyethylene test method."

  The gel referred to in the present invention refers to a cross-linked and polymerized resin, which is a part that is not plasticized at a normal molding temperature, for example, 180 ° C. If this part increases, heat resistance will improve, but moldability will fall. Therefore, this ratio (hereinafter referred to as a gel fraction in the present invention) is arbitrarily selected according to the molding method.

  The gel fraction of the polyolefin foam sheet of the present invention is 20% or more and 75% or less. Preferably they are 30% or more and 70% or less. If it is lower than 25%, the heat resistance is lowered, the foamed foam is deteriorated during the molding process, making it difficult to perform a good molding process, and if it is higher than 75%, the target flexibility is impaired.

  The polyolefin foam sheet used in the present invention has a tactile value of 3.2 or less. The tactile sensation value is a numerical value measured according to VDA237-101 (1996). As a measuring method, a circular object having a diameter of 14 mm and rounded by 0.3 mm square is pressed against the foamed sheet at 5 mm / min. The test ends when the load reaches 60 N or is pushed in 2.1 mm. Then, the indentation amount (mm) and the load (N) of the test result are plotted, the largest inclination of the plotted curve is obtained, and the smallest inclination is obtained separately, and the value is calculated as follows.

Tactile value = “largest slope of curve” / “smallest slope of curve”
The tactile value is preferably 3.2 or less, more preferably 3.0 or less, and particularly preferably 2.8 or less.

  The polyolefin foam sheet used in the present invention preferably has a hardness of 25 degrees or more and 80 degrees or less measured based on ASTM D2240 using a type OO durometer. More preferably, they are 30 degree | times or more and 70 degrees or less, More preferably, they are 47 degree | times or more and 64 degrees or less. If the numerical value is lower than 25 degrees, there is no “stiffness” as a foam, and if the numerical value is higher than 80 degrees, it is not a polyolefin foam sheet having sufficient flexibility.

  The thickness of the polyolefin foam sheet is desirably 1.0 mm or more. Preferably it is 1.5 mm or more. If it is less than 1.0 mm, it is difficult to obtain a tactile feel rich in flexibility.

  The polyolefin foam sheet of the present invention has a shrinkage rate of 5% or less when treated at 120 ° C. for 1 hour, and preferably 10% or less when treated at 140 ° C. for 10 minutes. When the shrinkage rate is larger than the specified value at 120 ° C. and 140 ° C., it means that the film shrinks greatly during the molding process by heating, and it becomes difficult to process in accordance with the specified dimensions.

The relation between the 25% compressive strength at normal temperature and the density of the polyolefin foam sheet is preferably in the following range.
Compressive strength: 34 kPa or less Density: ~ 40 kg / m ³
Compressive strength: 50 kPa or less Density: 40-60 kg / m ³
In the case of compressive strength: 65 kPa or less Density: 60-80 kg / m ³
In the case of compressive strength: 80 kPa or less Density: 80-100 kg / m ³
In the case of compressive strength: 96 kPa or less Density: 100-119 kg / m ³
If it is out of this range, it is difficult to achieve both flexibility and “koshi” when contacting.

  The foam of the present invention is produced by mixing a foaming agent capable of generating a gas into the polyolefin resin composition before foaming (in addition, as a foaming agent, a pyrolytic chemical). Atmospheric pressure foaming method in which foaming agent is added and melted and kneaded and foamed by normal pressure heating. Pyrolysis chemical foaming agent is thermally decomposed in an extruder and extruded while being extruded under high pressure. Examples thereof include a press foaming method in which a thermally decomposable chemical foaming agent is thermally decomposed and foamed under reduced pressure, and an extrusion foaming method in which a solvent that is gas or vaporized is melt-mixed in an extruder and foamed while being extruded under high pressure.

  The thermally decomposable chemical foaming agent used here is a chemical foaming agent that decomposes when heated to release gas. For example, azodicarbonamide, hydrazodicarbonamide, azodicarboxylic acid barium salt, nitrosoguanidine, p, p'-oxybisbenzenesulfonyl semicarbazide, benzenesulfonyl hydrazide, N, N'-dinitrosopentamethylenetetramine, toluenesulfonyl hydrazide, 4,4-oxybis (benzenesulfonyl hydrazide), azobisisobutyronitrile, etc. Inorganic foaming agents such as organic foaming agents, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate and calcium azide can be mentioned.

  Examples of the gas or the solvent to be vaporized include gases such as carbon dioxide, nitrogen and helium, and vaporized solvents such as propane, normal butane and isobutane.

A foaming agent can be used individually or in combination of 2 types or more, respectively. In order to obtain a high-magnification foam that is flexible and has high moldability and a smooth surface, a normal pressure foaming method using azodicarbonamide as a foaming agent is preferably used.
The addition amount of the pyrolytic foaming agent is not particularly limited, and is preferably 1 to 30 parts by mass and more preferably 3 to 25 parts by mass with respect to 100 parts by mass of the polyolefin resin.

  If the amount of the pyrolytic foaming agent added relative to 100 parts by mass of the polyolefin resin is less than 1 part by mass, the polyolefin resin may not sufficiently foam, and if it exceeds 30 parts by mass, bubbles may break during foaming. It is because it becomes easy to raise | generate and it becomes impossible to obtain a desired polyolefin resin crosslinked foam sheet.

  The crosslinking aid is not particularly limited as long as it is a crosslinking aid that has been conventionally used in the production of foams. For example, triallyl trimellitate, triallyl melitte, diallyl melitte, diallyl Phthalate, divinylbenzene, trimethylolpropane trimethacrylate, 1,9-nonanediol dimethacrylate, 1,10-decanediol dimethacrylate, trimellitic acid triallyl ester, triallyl isocyanurate, ethyl vinylbenzene, neopentyl glycol dimethacrylate 1,2,4-benzenetricarboxylic acid triallyl ester, 1,6-hexanediol dimethacrylate and the like. The crosslinking aids may be used alone or in combination of two or more.

 And although the addition amount of the said crosslinking adjuvant is not specifically limited, 0.5-20 mass parts is preferable with respect to 100 mass parts of said polyolefin resin, and 2-10 mass parts is more preferable.

  If the addition amount of the crosslinking aid relative to 100 parts by mass of the polyolefin resin composition is less than 0.5 parts by mass, the effect of adding the crosslinking aid may not be sufficiently obtained, and 20 parts by mass. This is because the polyolefin resin is excessively cross-linked and foaming may be inhibited.

  Moreover, the gel fraction of a polyolefin foamed sheet is mentioned as one standard of the addition amount of a crosslinking agent or a crosslinking adjuvant. That is, it is preferable to adjust the addition amount of the crosslinking aid so that the resulting polyolefin foam sheet has a gel fraction of 20 to 75 mass%, and the polyolefin resin crosslinked foamed sheet has a gel fraction of 35 to 70 mass%. More preferably, the addition amount of the crosslinking aid is adjusted.

  The method for crosslinking the foam of the present invention may be a conventionally known method, and the production method is not particularly limited. In the method of irradiating a sheet material with a predetermined dose of ionizing radiation to crosslink the resin, an electron beam, X-ray, β-ray, γ-ray or the like is used as the ionizing radiation. The irradiation dose is generally about 1 to 300 kGy, and the dose is set according to a desired gel fraction. In addition, a method such as crosslinking with a peroxide such as dicumyl peroxide or silane crosslinking can also be used.

  The polyolefin resin composition used in the present invention includes, for example, phenolic compounds such as 2,6-di-t-butyl-p-cresol, phosphorous and the like within a range not impairing the physical properties of the polyolefin foam sheet. -Based, amine-based, sulfur-based antioxidants such as dilauryl thiodipropionate (anti-aging agent), metal harm-preventing agents such as methylbenzotriazole, phosphorus-based, nitrogen-based, halogen-based, antimony-based and these Additives such as flame retardants such as mixtures, inorganic fillers, organic fillers, lubricants, antistatic agents, and colorants (inorganic pigments and organic pigments) may be added. In addition, one type or two or more types of additives may be added.

  And the skin material may be laminated and integrated on the other surface of the polyolefin foam sheet. That is, the laminate of the present invention is obtained by laminating at least one selected from the group consisting of a film, a cloth, a nonwoven fabric and a leather and the polyolefin foam sheet of the present invention.

  As described above, in the case where the skin material is laminated and integrated on the other surface of the polyolefin foam sheet, the skin material may be laminated and integrated on the other surface of the polyolefin foam sheet in advance before molding, or the polyolefin foam The skin material may be detachably laminated on the other surface of the sheet, and the skin material may be laminated and integrated on the other surface of the polyolefin foam sheet during stamping molding.

  Examples of the skin material include a polyvinyl chloride sheet, a sheet made of a mixed resin of polyvinyl chloride and ABS resin, a thermoplastic elastomer sheet, a woven fabric, a knitted fabric, and a non-woven fabric.

  Also, when molding a polyolefin foam sheet by vacuum molding, a thermoplastic resin is laminated and integrated on one side of the polyolefin foam sheet, and a skin material is laminated on the other side of the polyolefin resin cross-linked foam sheet as necessary. After the integration, the polyolefin resin cross-linked foam sheet, the thermoplastic resin, and, if necessary, the skin material may be heated to a predetermined temperature and vacuum molded to form a desired shape.

  The evaluation methods used in the following examples and comparative examples are as follows.

(1) Foam thickness:
The thickness of the foam is a value measured according to ISO 1923 (Revised 1981/09/01) “Measurement method for foamed plastic and rubber linear dimensions”.

(2) Apparent density of foam:
The apparent density of the foam is a value measured according to JIS K6767 (Revised 1999/10/20) “Foamed plastics-polyethylene test method”.

(3) Gel fraction of foam:
The foam is cut into about 0.5 mm squares, and about 100 mg is weighed to the nearest 0.1 mg. After being immersed in 200 ml of tetralin at a temperature of 130 ° C. for 3 hours, it is naturally filtered through a 100 mesh stainless steel wire mesh, and the insoluble matter on the wire mesh is dried in a hot air oven at 120 ° C. for 1 hour. Next, the mixture is cooled in a desiccator containing silica gel for 10 minutes, the mass of this insoluble matter is accurately weighed, and the gel fraction of the foam is calculated as a percentage according to the following formula.
Gel fraction (%) = {mass of insoluble matter (mg) / weight of weighed foam (mg)} × 100
(4) MI of polyolefin resin:
The MI of the polyolefin resin was measured at a temperature of 190 ° C. and MI (230 ° C.) of 230 ° C. according to JIS K7210 (Revised 1999/10/20).

(5) Density of polyolefin resin:
The density of the polyolefin-based resin was measured according to JIS K7112 (Revised 1999/05/20) “Plastic—Method for measuring density and specific gravity of non-foamed plastic”.

(6) Melting point and crystal melting energy of polyolefin resin:
In the present invention, the melting point is the maximum peak among the crystal melting peaks of the DSC curve.
Measurement was performed using a differential scanning calorimeter (DSC: Seiko Electronics Co., Ltd. RDC220-robot DSC). The measurement conditions were that the sample was heated to a temperature of 200 ° C. and melted at a rate of 10 ° C./min. After cooling to a temperature of −50 ° C., the temperature was raised at a rate of 10 ° C./min, and the crystal melting peak was measured.

(7) 25% compression hardness of the foam:
The 25% compression hardness of the foam is a value measured based on JIS K6767 (1999) “Foamed plastic-polyethylene test method”. Specifically, the foam is cut into 50 mm × 50 mm, stacked so that the thickness is 20 mm or more and 30 mm or less, and the initial thickness is measured. A sample was placed on a flat plate, and stopped by compressing at a speed of 10 mm / min up to 25% of the initial thickness, the load after 20 seconds was measured, and 25% compression hardness (kPa) was calculated by the following formula.
・ 25% compression hardness (kPa) = 25% compression and 20 seconds later (N) / 25 (cm ² ) / 10.
(8) Durometer hardness Type A and type OO were measured based on ASTM D2240 (2010).

(9) Evaluation method of flexibility of foam:
A “tactile value” was determined based on VDA237-101: 1996 as an index of flexibility.
As a measuring method, a circular object having a diameter of 14 mm and rounded by 0.3 mm square is pressed against the foamed sheet at 5 mm / min. The test ends when the load reaches 60 N or is pushed in 2.1 mm. Then, the indentation amount (mm) and the load (N) of the test result are plotted, the largest inclination of the plotted curve is obtained, and the smallest inclination is obtained separately, and the value is calculated as follows.

Tactile value = “largest slope of curve” / “smallest slope of curve”
(10) Heat molding processability:
The heat molding processability was evaluated by the molding drawing ratio H / D at the time of vacuum molding. In a vertical cylindrical female cup with a diameter of D and a depth of H, when the foam was heated and straight molded using a vacuum molding machine, the foam expanded and expanded without tearing. This was done by comparing the values with the largest H / D values. The diameter D used a cup of 50 mm, and the foam temperature was measured according to JIS K7133 (established in 1999). Was allowed to stand for 1 hour in a temperature atmosphere described in Table 1, and the dimensional change after heating was measured. The dimensional change was measured in the width direction during foam production.

(Examples 1-9, Comparative Examples 1-8)
100 parts by mass of an olefin resin obtained by blending a specified amount of an olefin block copolymer (A) and a polypropylene resin (B) according to Table 1, azodicarbonamide (ADCA) (Vinole AC # R manufactured by Eiwa Kasei Kogyo Co., Ltd.) as a foaming agent, Antioxidants (“IRGANOX” (registered trademark) 1010 manufactured by BASF) and a crosslinking aid (80% divinylbenzene manufactured by Wako Pure Chemical Industries, Ltd.) were added in specified amounts according to Table 1, mixed using a Henschel mixer, and Table 1 Then, it was melt-extruded with an extruder under temperature conditions, and polyolefin resin sheets having various thicknesses shown in Table 1 were prepared using a T-die.

  The polyolefin-based resin sheet thus obtained was irradiated from one side under the conditions shown in Table 1 to obtain a crosslinked sheet, and then the crosslinked sheet was floated on a salt bath at a temperature of 220 ° C. It was heated with a heater and foamed. The foam was cooled with water at a temperature of 60 ° C., and the foam surface was washed with water and dried to obtain a long roll of foam whose thickness, apparent density, and gel fraction are shown in Table 1. The evaluation results of this foam are shown in Table 1.

  Details of each olefin block copolymer (A), polypropylene resin (B) and other resins used this time are shown in Table 2.

  In the table, “parts” means “parts by mass”.

  As is clear from Table 1, the olefin block copolymer (A) and the polypropylene resin (B) in Examples 1 to 8 are added in a specified amount, and the 25% compressive strength and tactile value, which are indices of flexibility, are good. In addition, an olefin foamed sheet having a good heat shrinkage, which is an index of heat resistance, could be produced. In Comparative Examples 1 to 5, ultra-low density polyethylene having good flexibility is added as the third component, but the heat shrinkage rate, which is an index of heat resistance, is increased, causing problems during molding. Further, Comparative Examples 6 to 8 are systems in which no olefinic block copolymer is added, but the heat shrinkage rate, which is an index of heat resistance, is increased, causing problems during molding.

Claims (6)

Including 15 to 75 parts by mass of an olefin block copolymer (A) having a melting point of 115 ° C. or higher and a melt index (hereinafter referred to as MI) of 0.1 to 40 g / 10 min (190 ° C.),
85 parts by mass or more and 25 parts by mass or less of a polypropylene resin (B) having an MI of 0.1 to 25 g / 10 min (230 ° C.),
The gel fraction is 20-75%,
A polyolefin foam sheet characterized by having a density of 25 to 250 kg / m ³ .   2. The polyolefin foam sheet according to claim 1, wherein the tactile value measured according to VDA237-101 (1996) is 3.2 or less.   The polyolefin according to claim 1 or 2, wherein the shrinkage rate when treated at 120 ° C for 1 hour is 5% or less and the shrinkage rate when treated at 140 ° C for 10 minutes is 10% or less. Foam sheet.   The polypropylene resin (B) is a propylene homopolymer and / or a propylene-olefin copolymer. The polyolefin foam sheet in any one of Claims 1-3.   The polyolefin foam sheet according to any one of claims 1 to 4, wherein the thickness is 1.0 mm or more.   The laminated product which laminated | stacked 1 type chosen from the group which consists of a film, a cloth, a nonwoven fabric, and leather, and the polyolefin foam sheet in any one of Claims 1-5.