JP2000246850A - Laminated sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve light weight properties and a mechanical strength by laminating propylene resin sheets on both surfaces of a crosslinked olefin resin foamed sheet for obtaining melt energy per specific unit weight, and forming any one of the sheets of a propylene resin, an ethylene resin and an inorganic filler. SOLUTION: A melt energy of 120 deg.C or above contained in a melt energy per unit weight is increased more than 60 mJ/mg, and a melt energy of 140 deg.C or above is increased by 40 mJ/mg 91 m, and propylene resin sheets are laminated on both surfaces of the crosslinked olefin resin foamed sheet obtained by foaming by using a pyrolytic foaming agent. One of the propylene resin sheets contains a propylene resin, an ethylene resin and an inorganic filler. Thus, light weight properties and a mechanical strength can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated sheet which is excellent in lightness and mechanical strength and is used for interior materials for automobiles and the like.

[0001]

2. Description of the Related Art Interior materials for automobiles, particularly ceiling materials for automobiles, are required to have many performances such as light weight, moldability, heat resistance, bending resistance, and soundproofing performance. As a device satisfying these requirements, Japanese Patent Publication No. 6-24767 discloses a laminated sheet in which a propylene-based resin sheet is laminated on one surface of a crosslinked foamed sheet made of an ethylene-based resin and a propylene-based resin.

However, the above-mentioned laminated sheet does not satisfy both the lightness and the mechanical strength.

[0003]

SUMMARY OF THE INVENTION The present invention provides a laminated sheet having excellent lightness and mechanical strength.

[0004]

According to the first aspect of the present invention, the laminated sheet according to the first aspect has a melting energy of 120 ° C. or higher which is included in the melting energy per unit weight (caloric value / weight obtained from the melting peak area in differential scanning calorimetry). Energy is 60mJ / m
g and a melting energy of 140 ° C. or more is 4
A propylene-based resin sheet is laminated on both sides of a crosslinked olefin-based resin foamed sheet obtained by foaming using a pyrolytic foaming agent while being larger than 0 mJ / mg, and at least one of these propylene-based resin sheets is used. One propylene-based resin sheet is a propylene-based resin,
It consists of an ethylene resin and an inorganic filler.

[0005] The melting energy per unit weight is obtained by dividing a calorific value (mJ) obtained from a melting peak area in differential scanning calorimetry by a sample weight (mg). Melting peak area of the differential scanning calorimetry was surrounded by the line connecting the melting peak curve measured according to JIS K7211 ^-1997, a melting initiation temperature portion and ending melting temperature portion of the melting peak curve This means the area of the portion (the area of the hatched portion in FIG. 1A). When an ethylene-based resin is contained as the olefin-based resin, the melting start temperature is set to 70 ° C.

As a specific method for measuring the melting energy per unit weight, SS
There is a method in which a melting peak curve of differential scanning calorimetry is measured by using a C5200 differential scanning calorimeter, a melting peak area is calculated from the melting peak curve, and a calorific value is obtained from the melting peak area.

The melting energy of 120 ° C. or more contained in the melting energy per unit weight is defined as the melting peak area of 120 ° C. or more with respect to the melting peak area of the differential scanning calorimetry (the hatched portion in FIG. 1B). Is calculated by multiplying the calorific value obtained from the melting peak area of the above differential scanning calorimetry by the above calculated percentage.

Similarly, the melting energy of 140 ° C. or more contained in the melting energy per unit weight refers to the melting peak area of 140 ° C. or more with respect to the melting peak area of the differential scanning calorimetry (FIG. 1C). (Shaded area) is calculated by multiplying the calorific value obtained from the melting peak area of the differential scanning calorimetry by the above calculated percentage.

As an example of a specific method for calculating the percentage of the melting peak area at a temperature of 120 ° C. or 140 ° C. or higher with respect to the melting peak area of the differential scanning calorimetry, a melting peak curve of the differential scanning calorimetry is copied on paper. Cutting out a portion surrounded by a straight line connecting the melting peak curve and the melting start temperature portion and the melting end temperature portion of the melting peak curve, and measuring the weight of the cut paper, while measuring the weight of the cut paper. The weight can be calculated by measuring the weight of the paper at a temperature of 120 ° C. or 140 ° C. or higher and dividing the weight of the paper at a temperature of 120 ° C. or 140 ° C. or higher by the weight of the entire cut paper.

The melting energy per unit weight in the crosslinked olefin resin foam sheet is 120
If the melting energy at a temperature of at least 0 ° C. is small, the high-temperature melting crystalline component is reduced and the heat resistance and the mechanical strength of the crosslinked olefin resin foam sheet are reduced, so that it is necessary to be larger than 60 mJ / mg.

Similarly, if the melting energy at 140 ° C. or higher included in the melting energy per unit weight in the above-mentioned crosslinked olefin resin foam sheet is small, the high-temperature melting crystalline component is reduced and the heat resistance of the crosslinked olefin resin foam sheet is reduced. 40 mJ / m
It must be larger than g.

When the melting energy per unit weight of the crosslinked olefin resin foam sheet is small, the amount of the crystalline component of the crosslinked olefin resin foam sheet is reduced, and the heat resistance of the crosslinked olefin resin foam sheet is reduced. In addition, 85 mJ / mg or more is preferable because the mechanical strength decreases.

As described above, the melting energy per unit weight included in the melting energy at 120 ° C. or higher is 60 m
By configuring the melting energy at greater than J / mg and at 140 ° C or more at greater than 40 mJ / mg, excellent heat resistance and mechanical strength can be imparted to the crosslinked olefin-based resin foam sheet.

Further, the melting energy at 120 ° C. or more contained in the melting energy per unit weight is 60 mJ / m
g and a melting energy of 140 ° C. or more is 4
By making the composition larger than 0 mJ / mg and the melting energy per unit weight to be 85 mJ / mg or more, the crosslinked olefin-based resin foam sheet
More excellent heat resistance and mechanical strength can be provided.

The resin constituting the crosslinked olefin resin foam sheet is not particularly limited as long as a crosslinked olefin resin foam sheet having a melting energy satisfying the above range can be obtained. For example, propylene resin, ethylene resin And the like. These may be used alone or in combination. When used in combination, a combination of a propylene resin and an ethylene resin is preferable.

The propylene resin (hereinafter referred to as “propylene resin (A)”) includes, for example, propylene as a main component (more than 50% by weight) in addition to homopolypropylene.
And a homopolypropylene is preferred.

The copolymer of propylene and α-olefin may be a block copolymer, a random copolymer,
Alternatively, any of random block copolymers may be used. Examples of the α-olefin include ethylene and 1-olefin.
Hexene, 4-methyl-1-pentene, 1-octene,
Examples thereof include 1-butene, 1-pentene, 1-heptene and the like.

Among the homopolypropylenes, highly crystalline isotactic homopropylene is preferable, and isotactic homopropylene having a pendat fraction of 96% or more is more preferable.

When the melt index (hereinafter referred to as “MI”) of the above isotactic homopolypropylene is high, the foaming property may be reduced. On the other hand, when the melt index is low, the melt viscosity increases and the thermal decomposition type foaming agent may be used. Since primary foaming may occur in the sheet obtained when kneading and extruding,
5 to 30 g / 10 min is preferred. In the present invention, the MI of the propylene-based resin refers to JIS K7210.
Is measured under the conditions of a temperature of 230 ° C. and a load of 2.16 kgf.

The above-mentioned propylene as a main component (more than 50% by weight)
When the MI of the copolymer with α-olefin is high,
If the foaming property is low, and if the foaming property is low, the melt viscosity increases, and the sheet obtained when kneading and extruding the pyrolytic foaming agent may cause primary foaming, so that 0.1 to 10 g / 10
Minutes, more preferably 0.3 to 8 g / 10 minutes.

When the content of the propylene-based resin (A) in the resin constituting the crosslinked olefin-based resin foamed sheet increases, the surface property of the crosslinked olefin-based resin foamed sheet obtained by primary foaming in the production process is reduced. Or, or may not be able to obtain the desired expansion ratio,
On the other hand, if the amount is small, the high-temperature strength of the obtained cross-linked olefin resin foam sheet may decrease, so that the content is preferably 10 to 90% by weight.

That is, in the resin constituting the crosslinked olefin resin foam sheet, it is preferable that isotactic homopolypropylene having an MI of 5 to 30 g / 10 min is 10 to 90% by weight.

The ethylene resin (hereinafter referred to as “ethylene resin (A)”) includes, for example, low-density polyethylene, medium-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene, and high-density polyethylene. ,
Copolymers with an α-olefin containing ethylene as a main component (more than 50% by weight) are exemplified. As the α-olefin, for example, propylene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-butene, 1-
Pentene, 1-heptene and the like.

In order to increase the melting energy per unit weight of the crosslinked olefin resin foam sheet, it is preferable to use a high-density polyethylene having a density of 0.95 g / cc or more.

When the MI of the ethylene-based resin (A) is high, the moldability of the crosslinked olefin-based resin foam sheet is reduced. On the other hand, when the MI is low, the melt viscosity is increased and the thermal decomposition type foaming agent is kneaded. Since primary foaming may occur in the sheet obtained at the time of extrusion, it is preferably 0.5 to 15 g / 10 min, more preferably 2 to 15 g / 10 min. In the present invention, the MI of the ethylene-based resin refers to JIS K72.
10, measured at a temperature of 190 ° C. under a load of 2.16 kgf.

If the content of the ethylene resin (A) in the resin constituting the crosslinked olefin resin foam sheet is small, the rigidity of the resulting crosslinked olefin resin foam sheet may be reduced. It is preferably at least 10% by weight.

That is, in the resin constituting the crosslinked polyolefin resin foam sheet, MI is 0.5 to 15 g / 10
It is preferable to contain 10% by weight or more of high-density polyethylene having a density of 0.95 g / cc or more.

When the propylene-based resin (A) and the ethylene-based resin (A) are used in combination, if the content of the propylene-based resin (A) is large, the melt viscosity increases and the thermal decomposition foaming Primary foaming may occur in the sheet obtained when the agent is kneaded and extruded, and if the amount is small, the heat resistance and mechanical strength of the obtained crosslinked olefin resin foam sheet may be reduced. ~ 90% by weight is preferred.

As the resin constituting the crosslinked olefin resin foam sheet, in addition to the olefin resin, ethylene-propylene rubber, styrene-isoprene-styrene rubber (SIS), styrene-ethylene-butadiene-
Styrene rubber (SEBS) or the like may be added as long as the physical properties of the crosslinked olefin resin foam sheet are not impaired.

Further, the crosslinked olefin-based resin foam sheet is obtained by foaming using a pyrolytic foaming agent. When the foaming method of foaming using the pyrolytic foaming agent is used, A crosslinked structure can be imparted to the foamed sheet.

That is, the olefin resin is selected so that the fusion energy of the crosslinked olefin resin foamed sheet is within the above range, and the foamed sheet is foamed with a pyrolytic foaming agent to introduce a crosslinked structure into the obtained foamed sheet. By the synergistic effect of both, excellent heat resistance, mechanical strength and moldability can be imparted to the crosslinked olefin resin foam sheet.

Furthermore, since a foamed sheet having a high expansion ratio can be obtained by introducing a crosslinked structure into the foamed sheet, the resulting crosslinked olefin resin foamed sheet is excellent in lightness.

When the density of the crosslinked olefin-based resin foam sheet is reduced, the mechanical strength of the crosslinked olefin-based resin foam sheet may be reduced, and when the density is large, the lightness of the crosslinked olefin-based resin foam sheet is reduced. Is preferably 0.02 to 0.20 g / cc,
0.03 to 0.10 g / cc is more preferable.

As a method for producing the crosslinked olefin resin foam sheet, for example, a foaming resin composition comprising the olefin resin and a pyrolytic foaming agent may be added with a crosslinking aid as necessary. The foamable resin composition is supplied to an extruder, melt-kneaded to extrude a foamable resin molded article, and a predetermined amount of ionizing radiation is applied to the obtained foamable resin molded article to form the foamable resin molded article. A method of producing a crosslinked olefin resin foam sheet by heating the crosslinked foamable resin molded article to a temperature not lower than the decomposition temperature of the pyrolytic foaming agent after imparting a crosslinked structure to the olefin resin, A cross-linking agent and, if necessary, a cross-linking aid are added to a foaming resin composition comprising a mold foaming agent, and then the foaming resin composition is supplied to an extruder and melt-kneaded to form a foaming resin composition. Pushing out the body, this Was such a method of producing a heated and crosslinked olefin-based resin foam sheet to a temperature higher than the decomposition temperature of the thermally decomposable foaming agents by the extruding a foamable resin molded body at the same time the heating roll or the like.

When the foamable resin composition is supplied to an extruder and melted and kneaded, if the melt viscosity of the foamable resin composition is large, primary foaming occurs and the resulting crosslinked olefin resin foam sheet is formed. Since the surface properties may be reduced or the desired expansion ratio may not be obtained in the subsequent foaming, the melt viscosity of the foamable resin composition may be 1
It is preferable to adjust so as to be not more than 000 poise.

The pyrolytic foaming agent is not particularly limited as long as it has been conventionally used for producing foams. Examples thereof include azodicarbonamide, dinitrosopentamethylenetetramine, hydradodicarbonamide, and azodicarbonamide. Barium acid salt, nitrosoguanidine, p, p
^, -Oxybisbenzenesulfonyl semicarbazide, benzenesulfonylhydrazide, N, N ^, -dinitrosopentamethylenetetramine, toluenesulfonylhydrazide, 4,4-oxybis (benzenesulfonylhydrazide), azobisisobutyronitrile and the like.

The amount of the above-mentioned pyrolytic foaming agent is appropriately adjusted. If the amount is large, the foam may be broken. If the amount is small, the foam may not be foamed. The amount is preferably 1 to 50 parts by weight, more preferably 1 to 30 parts by weight.

The crosslinking assistant is not particularly limited.
For example, divinylbenzene, trimethylolpropane trimethacrylate, 1,9-nonanediol dimethacrylate, 1,10-decanediol dimethacrylate,
Examples include triallylic acid triallyl ester, triallyl isocyanurate, ethylvinylbenzene, neopentyl glycol dimethacrylate, 1,2,4-benzenetricarboxylic acid triallyl ester, 1,6-hexanediol dimethacrylate, and the like.

The amount of the crosslinking aid is appropriately adjusted. If the amount is too large, the crosslinking of the expandable resin molded article may proceed too much to hinder foaming. If the amount is too small, the added effect may not be obtained. Therefore, the amount is preferably 0.5 to 30 parts by weight, more preferably 2.0 to 15 parts by weight, based on 100 parts by weight of the olefin resin.

The crosslinking agent is not particularly restricted but includes, for example, isobutyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane-3, 1,3 -Bis (t-butylperoxyisopropyl) benzene, t-butylcumyl peroxide, di-t-butyl peroxide, t-butylperoxybenzoate, cyclohexane peroxide, 1,1-bis (t-butylperoxy) Cyclohexane, 1,1-bis (t-butylperoxy) 3,
3,5-trimethylcyclohexane, 2,2-bis (t
-Butylperoxy) octane, n-butyl-4,4-
Bis (t-butylperoxy) bellate, benzoyl peroxide, cumylperoxyneodecanate,
2,5-dimethyl-2,5-di (benzoyloperoxy) hexane, t-butylperoxyisopropyl carbonate, t-butylperoxyallyl carbonate,
t-butyl peroxyacetate, 2,2-bis (t-
(Butylperoxy) butane, di-t-butylperoxyisophthalate, t-butylperoxymaleic acid and the like.

If the amount of the cross-linking agent is large, the cross-linking density may be too high to cause foaming. If the amount is small, the cross-linking density may be insufficient and the shear viscosity required for foaming may not be obtained. Therefore, the amount is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the olefin resin.

The amount of the crosslinking aid and crosslinking agent to be added is indicated by the gel fraction, and the crosslinked olefin resin foam sheet to be obtained preferably has a gel fraction of 20 to 75.
The addition amount of the crosslinking assistant may be adjusted so as to be 30% by weight, more preferably 30 to 65% by weight.

Here, in the present invention, the gel fraction means that the crosslinked olefin resin foam sheet is weighed with Ag,
It is immersed in xylene at 20 ° C. for 24 hours, the residue is filtered through a 200-mesh wire gauze, the insoluble matter on the wire gauze is dried in vacuum, and the weight at that time is measured (Bg), which is calculated by the following equation. It is. Gel fraction (% by weight) = 100 × B / A

The ionizing radiation is not particularly limited as long as it has been conventionally used for crosslinking a foamable resin molded article, and examples thereof include α rays, β rays, gamma rays, and electron beams. .

In the foamable resin composition, in addition to the crosslinking aid, a phenolic compound such as 2,6-di-t-butyl-p-cresol and a phosphorus-based compound may be used as long as foaming properties are not impaired. , Amine-based, dilaurylthiodipropionate, etc. sulfur-based antioxidants; metal toxic inhibitors such as methylbenzotriazole, phosphorus-based, nitrogen-based, halogen-based, antimony-based and flame retardants obtained by mixing these , A filler, an antistatic agent, a pigment and the like may be added.

A propylene resin sheet is laminated on both sides of the crosslinked olefin resin foam sheet. As the propylene-based resin (hereinafter referred to as “propylene-based resin (B)”) constituting the propylene-based resin sheet, the same propylene-based resin (A) as above is used. And a block propylene resin, and when used in combination, a combination of a homopolypropylene and a block propylene resin is preferable.

If the melting point of the propylene-based resin (B) is high, the secondary workability may be reduced.
The temperature is preferably from 160 to 170 ° C. because the heat resistance of the obtained laminated sheet may be unexpected. In addition, the melting point of the resin in the present invention refers to a peak temperature of a differential thermal analysis curve at a heating rate of 10 ° C./min.

If the MI of the propylene-based resin (B) is high, the melt viscosity may be reduced to make it difficult to form a sheet. If the MI is low, the molding distortion may occur when the resulting laminated sheet is formed. 0.3 to 15 g / 10 min is preferable, since it is likely to remain and the molding stability of the laminated sheet may decrease.

At least one of the propylene resin sheets laminated on both sides of the crosslinked olefin resin foam sheet comprises at least one of the propylene resin (B), the ethylene resin, and the inorganic filler. Consisting of

As the ethylene-based resin (hereinafter referred to as “ethylene-based resin (B)”), the same as the above-mentioned ethylene-based resin (A) is used. When the MI of the ethylene-based resin (B) is high, the melt viscosity is reduced, and it may be difficult to form a sheet. When the MI is low, molding distortion tends to remain when the obtained laminated sheet is formed, Since the molding stability of the laminated sheet may be reduced,
15 g / 10 min is preferable, and 2 to 15 g / 10 min is more preferable.

When the content of the ethylene-based resin (B) in the propylene-based resin sheet is large, the heat resistance of the obtained laminated sheet may be reduced. If the laminated sheet is deformed under high temperature at the time of molding, or is highly stretched during secondary processing or the like, the surface of the laminated sheet is easily whitened if the stress relaxation property is reduced. 1 for 100 parts by weight
-100 parts by weight are preferred.

The form of the inorganic filler is not particularly limited, whether it is powdery, balun or fibrous. Examples of the powdery inorganic filler include calcium carbonate, talc, kaolin clay, mica, Titanium oxide and the like, as examples of the balun-like inorganic filler, for example, silas balun, glass balun, fly ash balun, and the like, as the fibrous inorganic filler, for example, glass fiber,
Whiskers and the like. Among these inorganic fillers, calcium carbonate, talc, and mica are preferred, and talc and mica are more preferred, from the viewpoint that the effect of improving rigidity with respect to the resin is large and the obtained laminated sheet has excellent molding stability.

When the size of the inorganic filler is increased, the impact strength of the laminated sheet at a low temperature is reduced. Therefore, the particle size or the fiber diameter is preferably 20 μm or less.

If the content of the inorganic filler in the propylene-based resin sheet is large, the resulting laminated sheet may have a reduced lightness, or the surface of the laminated sheet may be whitened during secondary processing, If the amount is small, the rigidity of the laminated sheet is reduced. Therefore, the amount is preferably from 1 to 120 parts by weight based on 100 parts by weight of the propylene-based resin (B).

In the laminated sheet, both of the propylene resin sheets laminated on both sides of the crosslinked olefin resin foam sheet are composed of the propylene resin (B), the ethylene resin (B) and the inorganic filler. It may be something.

Among the propylene resin sheets laminated on both sides of the crosslinked olefin resin foam sheet, a propylene resin sheet comprising the propylene resin (B), the ethylene resin (B) and an inorganic filler is used. The other propylene-based resin sheet may be made of the propylene-based resin (B) or may be made of the propylene-based resin (B) and the ethylene-based resin (B).

Next, a method of manufacturing a laminated sheet will be described. The laminated sheet of the present invention is obtained by laminating and integrating a predetermined propylene-based resin sheet on both sides of a cross-linked olefin-based resin foam sheet.
A known method can be adopted, and there is no particular limitation. For example, a method of manufacturing a laminated sheet by laminating and integrating a propylene-based resin sheet separately manufactured in advance with heat lamination or an adhesive on both sides of a cross-linked olefin-based resin foam sheet A method of manufacturing a laminated sheet by extrusion laminating a propylene-based resin sheet on both sides of a cross-linked olefin-based resin foam sheet, preparing two cross-linked olefin-based resin foam sheets, A propylene-based resin sheet is extrusion-laminated to produce two cross-linked foamed laminated sheets in which the propylene-based resin sheet is laminated and integrated on one surface, and the cross-linked olefin-based resin foamed sheets of the obtained two cross-linked foamed laminated sheets are joined together. A method of manufacturing a laminated sheet by integrating by heat fusion is exemplified.

When the thickness of the propylene resin sheet laminated on both sides of the crosslinked olefin resin foam sheet is large, the lightness of the obtained laminated sheet is reduced. Since the mechanical strength such as strength may be reduced and the moldability may be reduced, it is preferably adjusted to be 0.1 to 1 mm.

Further, a general-purpose engineering resin sheet of polyamide or polyester may be laminated on the surface of the propylene resin sheet as long as the secondary workability is not impaired.

Next, the laminated sheet according to claim 3 will be described. The description of the same configuration as that of the above-described laminated sheet will be omitted. The laminated sheet according to claim 3, wherein the melting energy per unit weight (heat value / weight obtained from the melting peak area of differential scanning calorimetry) at 120 ° C. or higher is greater than 60 mJ / mg; The melting energy at 140 ° C. or higher is larger than 40 mJ / mg,
A propylene-based resin sheet is laminated on both sides of a cross-linked olefin-based resin foam sheet obtained by foaming using a pyrolytic foaming agent, and at least one propylene-based resin sheet among these propylene-based resin sheets is The laminated sheet according to claim 1, comprising a propylene-based resin, a low-melting-point propylene-based resin, and an inorganic filler, wherein at least one of the propylene-based resin sheets is a propylene-based resin or a low-melting-point propylene-based resin. And an inorganic filler.

The low-melting-point propylene-based resin is not particularly limited as long as it has a melting point lower than that of the propylene-based resin (B). For example, propylene-α-olefin random copolymer, propylene -Ethylene-butene terpolymer and the like;
Examples of the olefin include ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene and the like, with ethylene being preferred.

Further, when the content of the α-olefin is large, the heat resistance of the skin layer decreases, and the grain retention property decreases,
On the other hand, if the amount is small, whitening may occur on the surface of the laminated sheet when it is formed. Therefore, the amount is preferably 2 to 10% by weight.

If the melting point of the low-melting point propylene resin is high, the surface of the laminated sheet may be whitened when the laminated sheet is molded, and if the melting point is low, the heat resistance of the laminated sheet is reduced and the molding stability is lowered. May decrease, so that 125 to 1
50 ° C. is preferred.

The MI of the low-melting-point propylene-based resin is set to 0.1 for the same reason as in the case of the propylene-based resin (B).
3-15 g / 10 min is preferred.

If the content of the low-melting-point propylene-based resin in the propylene-based resin sheet is large, the heat resistance of the skin layer may be reduced and the grain retention of the laminated sheet may be reduced. The stress relaxation of the resulting laminated sheet is reduced, and the sheet is deformed at a high temperature during molding, or
If the film is highly stretched during the secondary processing, the surface of the obtained molded article may be whitened and its surface properties may be reduced. Therefore, 1 to 100 parts by weight based on 100 parts by weight of the propylene-based resin (B). Is preferable, and 1 to 50 parts by weight is more preferable.

[0066]

EXAMPLES In Examples 1 and 2 and Comparative Examples 1 and 2, the following propylene resins and ethylene resins were used. Propylene resin (A) Homo PP; Isotactic homopropylene (Pendat fraction = 98%, MI = 15/10 min, melting point 167.8)
℃)

PE copolymer 1; propylene-ethylene copolymer (ethylene content = 3.2% by weight, MI = 2.
0 g / 10 min, melting point = 150.5 ° C)

Propylene resin (B) PE copolymer 2: propylene-ethylene block copolymer (MI = 4 g / 10 min, melting point = 166.7 ° C.)

Low-melting propylene resin PE copolymer 3: propylene-ethylene random copolymer (MI = 1.5 g / 10 min, melting point = 136.2 ° C.)

Ethylene resin (A) HDPE; high density polyethylene (density = 0.969 g /
cc, MI = 5.0 g / 10 min)

LLDPE1: Octene copolymerized linear low-density polyethylene (density = 0.920 g / cc, MI =
2.0 / 10 minutes)

Ethylene resin (B) LLDPE2; linear low density polyethylene (density = 0.
920 g / cc, MI = 1 g / 10 min)

The crosslinked olefin resin foams used in Examples 1 and 2 and Comparative Examples 1 and 2 were produced in the following manner. Homo PP, PE copolymer 1, HDPE in the amounts shown in Table 1
And LLDPE1, 4.0 parts by weight of trimethylolpropane trimethacrylate as a crosslinking aid, 7.5 parts by weight of azodicarbonamide as an organic pyrolytic foaming agent, and 2,6-di-t-butyl-p as an antioxidant. 0.3 parts by weight of cresol and 0.1 part of dilaurylthiodipropionate.
A foaming resin composition comprising 3 parts by weight and 0.5 parts by weight of methylbenzotriazole as a metal harm inhibitor was supplied to a twin-screw extruder (type: PCM87, manufactured by Ikegai Iron Works Co., Ltd.).
The mixture was melt-kneaded at a temperature of 190 ° C. and extruded into a sheet to obtain a foamable resin sheet having a thickness of 1.3 mm.

After one side of the obtained foamable resin sheet is irradiated with an electron beam 3Mrad at an acceleration voltage of 800 kV to crosslink the foamable resin sheet, the crosslinked foamable resin sheet is placed in an oven at a temperature of 250 ° C. To obtain a crosslinked olefin resin foam sheet having a thickness of 4 mm and an expansion ratio of 20 times.

Melting energy per unit weight of the obtained crosslinked olefin resin foam sheet, normal temperature and 100 ° C.
, The stress at 20% elongation, the density and the gel fraction were measured by the following methods. The results are shown in Table 2.

(Melting energy) The melting peak curve of the obtained cross-linked olefin resin foam sheet was measured according to JIS K72.
11 ^-1997 in compliance with a differential scanning calorimeter (Seiko Instruments Ltd. SSC5200) heating temperature 10 ° C. using a /
It was measured in min.

Then, the melting energy per unit weight ΔH was calculated from the melting peak curve using the Analysis job program of the differential scanning calorimeter. Further, from the melting peak curve, the melting energy Δ
It was calculated H ₁₂₀ and 140 ° C. or more melting energy [Delta] H _140.

(Stress at 20% elongation) The crosslinked olefin resin foam sheet obtained at room temperature and 100 ° C.
% Elongation stress was measured in accordance with JIS K6767.

(Density) The density of the obtained cross-linked olefin-based resin foam sheet was measured with an electronic hydrometer (ED12 manufactured by Mirage Co., Ltd.).
0T).

[0080]

[Table 1]

[0081]

[Table 2]

Example 1 100 parts by weight of PE copolymer 2, 20 parts by weight of LLDPE2 and 60 parts by weight of talc having an average particle diameter of 10 μm were supplied to one twin-screw extruder.
And a propylene-based resin sheet having a thickness of 0.1 mm on one surface of the crosslinked olefin-based resin foam sheet shown in Table 1.
Extrusion lamination at 25 mm and propylene-ethylene block copolymer (MI = 1)
g / 10 min, melting point 166.5 ° C.), melt-kneaded at 210 ° C., and apply a propylene resin sheet having a thickness of 0.25 on the other surface of the crosslinked olefin resin foam sheet obtained above.
to produce a laminated sheet having a thickness of 4.5 mm. The bending strength of the obtained laminated sheet at room temperature and 85 ° C. was measured by the following method.
It was shown to.

(Bending Strength) The bending strength of the obtained laminated sheet at ordinary temperature and 85 ° C. was measured in accordance with JIS K7171. However, the size of the test piece is 50 × 150 m
m, and the load speed was 50 mm / min.

Example 2 In addition to using the crosslinked olefin resin foamed sheet shown in Table 1, the resin composition constituting the propylene resin sheet was 100 parts by weight of PE copolymer 2 and 100 parts by weight of PE copolymer. A laminated sheet was produced in the same manner as in Example 1 except that a polymer 3 consisting of 30 parts by weight and 60 parts by weight of talc having an average particle size of 10 μm was used. The bending strength of the obtained laminated sheet at normal temperature and 85 ° C. was measured in the same manner as in Example 1, and the results were shown in Table 3.
It was shown to.

Comparative Example 1 A laminated sheet was produced in the same manner as in Example 1 except that the foamed crosslinked olefin resin sheet shown in Table 1 was used. The bending strength of the obtained laminated sheet at ordinary temperature and 85 ° C. was measured in the same manner as in Example 1, and the results are shown in Table 3.

Comparative Example 2 Example 1 was repeated except that the foamed crosslinked olefin resin sheet shown in Table 1 was used and the thickness of the propylene resin sheet was 0.3 mm.
To obtain a laminated sheet. The bending strength of the obtained laminated sheet at ordinary temperature and 85 ° C. was measured in the same manner as in Example 1, and the results are shown in Table 3.

[0087]

[Table 3]

[0088]

The laminated sheet of the present invention is constituted by using a crosslinked olefin resin foamed sheet obtained by using a pyrolytic foaming agent and having a melting energy per unit weight of a predetermined value or more in a central layer thereof. Therefore, it is excellent in heat resistance, mechanical strength, moldability and light weight.

Further, at least one of the propylene-based resin sheets of the laminated sheet of the present invention comprises at least one of a propylene-based resin, an ethylene-based resin and an inorganic filler, or a propylene-based resin having a low melting point. Since it is composed of a propylene-based resin and an inorganic filler, the laminated sheet has good grain retention and thermal stability due to the propylene-based resin, and has good elongation properties of a low-melting-point propylene-based resin or an ethylene-based resin. And excellent thermal stability due to good stress relaxation.

Therefore, the laminated sheet of the present invention can be formed into a complicated shape while leaving the grain pattern formed on the surface well, and has excellent surface properties and thermal stability that do not cause whitening on the surface. A molded article having the same can be obtained.
Furthermore, since the inorganic filler is contained, the laminated sheet has excellent thermal stability and also has excellent mechanical strength such as impact strength.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a melting peak curve of a crosslinked olefin resin foam.

 ──────────────────────────────────────────────────続 き Continuing on the front page F-term (reference) 4F074 AA16 BA01 BB01 CA22 CC06Y CE02 CE46 CE98 DA35 DA57 4F100 AA01B AC10 AK03A AK04B AK07B AK07C AK63 AK64 AL02B BA03 BA08 BA10B BA10C BA15 CA01A CA02A CA23B01A01

Claims (4)

[Claims] 1. The melting energy at 120 ° C. or higher contained in the melting energy per unit weight (caloric value / weight obtained from the melting peak area in differential scanning calorimetry) is 60 m.
J / mg and a melting energy at 140 ° C. or higher are greater than 40 mJ / mg, and a propylene-based resin sheet is formed on both sides of a cross-linked olefin-based resin foamed sheet obtained by foaming using a pyrolytic foaming agent. A laminated sheet which is laminated, wherein at least one of the propylene-based resin sheets comprises a propylene-based resin, an ethylene-based resin, and an inorganic filler. 2. A propylene resin sheet comprising a propylene resin, an ethylene resin and an inorganic filler, comprising 100 parts by weight of a propylene resin, 1 to 100 parts by weight of an ethylene resin and 1 to 120 parts by weight of an inorganic filler. The laminated sheet according to claim 1, wherein: 3. The melting energy at 120 ° C. or higher contained in the melting energy per unit weight (caloric value / weight obtained from the melting peak area in differential scanning calorimetry) is 60 m.
J / mg and a melting energy at 140 ° C. or higher are greater than 40 mJ / mg, and a propylene-based resin sheet is formed on both sides of a cross-linked olefin-based resin foamed sheet obtained by foaming using a pyrolytic foaming agent. A laminated sheet, wherein at least one of the propylene-based resin sheets is laminated and comprises a propylene-based resin, a low-melting-point propylene-based resin, and an inorganic filler. 4. A propylene-based resin sheet comprising a propylene-based resin, a low-melting-point propylene-based resin and an inorganic filler, wherein the propylene-based resin sheet is 100 parts by weight of a homopolypropylene and / or a block propylene resin and has a melting point of 125 to 150 ° C. 1-100 parts by weight of resin and inorganic filler 1
The laminated sheet according to claim 3, wherein the laminated sheet comprises from to 120 parts by weight.