JP3077846B2 - Laminated polyolefin resin foam - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated polyolefin resin foam. More specifically, the present invention relates to a laminated polyolefin-based resin foam which has excellent antistatic properties and can be suitably used as a material for household goods such as bath mats, packings, heat insulating materials, automobile interior materials and the like.

[0002]

2. Description of the Related Art In general, foams made of a polyolefin resin, particularly a polyethylene resin or a polypropylene resin, are so hydrophobic that they generate remarkably static electricity, causing dust to adhere to the foam or discharge of the static electricity. Therefore, there is a problem that a shock is given to a human body, or a fire occurs in a process using a flammable organic solvent.

Conventionally, as a method for solving the above problem,
In order to impart antistatic properties to the foam, a method of adding an anionic, cationic or amphoteric surfactant is employed. In such a method, the surfactant has a molecular weight of at most about 500 to 600. Because it is relatively small, it evaporates during the production of the foam, and after it is made into a foam, it bleeds out over time, contaminating the surface of the foam, causing blocking, There is a problem that printability and vapor deposition properties are deteriorated.

Therefore, a laminated polyolefin foam having a polyolefin resin foam layer having excellent antistatic properties is a resin having one or more specific functional groups in the polyolefin resin foam layer, a special modified resin ( For example, it is obtained by laminating a polyolefin resin foam to which an additive having a relatively small molecular weight is added, or by subjecting these to a corona discharge treatment.

However, in the method of adding the specific resin, since none of the resins is a polyolefin-based resin, the adhesiveness with the polyolefin-based resin foam is deteriorated. Cannot be obtained, and since such a resin has poor compatibility with the polyolefin-based resin, there is a problem that voids are generated and the surface property is deteriorated.

[0006] When these resins and surfactants are incorporated into the foam, the volume of the product is increased unlike sheets and films. As a result, a large amount of the resins and surfactants described above is added. Otherwise, there is a problem that the antistatic property is hardly exhibited.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and is not only excellent in antistatic properties, but also has a laminated polyolefin resin foam which does not cause bleeding or blocking. It is intended to provide the body.

[0008]

The present invention provides a compound of the general formula (I):

[0009]

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(Wherein R ¹ represents a hydrogen atom or a methyl group) 45 to 98.5 mol% of an olefin structural unit represented by the following general formula (II):

[0011]

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(Wherein R ² represents an alkyl group having 1 to 4 carbon atoms) 0 to 15 mol% of an acrylate structural unit represented by the following general formula (III):

[0013]

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(Wherein R ³ represents an alkyl group having 8 to 18 carbon atoms or an aryl group having 8 to 18 carbon atoms), and 0.5 to 5 mol% of an alkylmaleimide structural unit represented by the following general formula (IV):

[0015]

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(Wherein R ⁴ is an alkylene group having 2 to 8 carbon atoms, R ⁵ and R ⁶ are alkyl groups having 1 to 4 carbon atoms, R ⁷ is an alkyl group having 1 to 12 carbon atoms, and 6 carbon atoms. To 12 arylalkyl groups, an epoxy group having 2 to 4 carbon atoms which may be substituted with an alkyl group or an alicyclic alkyl group having 6 to 12 carbon atoms, X is a halogen atom, CH ₃ OSO ₃ or C ₂ H ₅ OSO ₃ are shown) cationized maleimide structural units 1 to 35 mol% linear irregularly arranged with weight-average molecular weight from 1,000 to 50,000 polyolefin resins consisting represented by, and the general formula (I):

[0017]

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(Wherein R ¹ is the same as described above) 45 to 98.5 mol% of an olefin structural unit represented by the following general formula (II):

[0019]

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(Wherein R ² is as defined above) 0 to 15 mol% of an acrylate structural unit represented by the following general formula (V):

[0021]

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(Wherein R ¹ and R ³ are the same as above, m
Represents 0 or 1), and 0.5 to 5 mol% of an alkylmaleimide structural unit represented by the general formula (VI):

[0023]

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(Wherein R ¹ , R ⁴ , R ⁵ , R ⁶ , R ⁷ ,
X and m are the same as those described above) and comprise at least one polyolefin resin having a weight average molecular weight of 1,000 to 50,000, which is linearly and irregularly arranged and has 1 to 35 mol% of a cationized maleimide structural unit represented by the following formula: The present invention relates to a laminated polyolefin resin foam provided with a polyolefin resin foam layer.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to (A)
General formula (I):

[0026]

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(Wherein R ¹ represents a hydrogen atom or a methyl group) 45 to 98.5 mol% of an olefin structural unit represented by the general formula (II):

[0028]

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(Wherein R ² represents an alkyl group having 1 to 4 carbon atoms) 0 to 15 mol% of an acrylate structural unit represented by the following general formula (III):

[0030]

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Wherein R ³ represents an alkyl group or an aryl group having 8 to 18 carbon atoms, and 0.5 to 5 mol% of an alkylmaleimide structural unit represented by the general formula (IV):

[0032]

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Wherein R ⁴ is an alkylene group having 2 to 8 carbon atoms, R ⁵ and R ⁶ are alkyl groups having 1 to 4 carbon atoms, R ⁷ is an alkyl group having 1 to 12 carbon atoms, To 12 arylalkyl groups, an epoxy group having 2 to 4 carbon atoms which may be substituted with an alkyl group or an alicyclic alkyl group having 6 to 12 carbon atoms, X is a halogen atom, CH ₃ OSO ₃ or C ₂ H ₅ A polyolefin resin having a weight average molecular weight of 1,000 to 50,000 (hereinafter, referred to as polyolefin resin A) linearly and irregularly composed of 1 to 35 mol% of a cationized maleimide structural unit represented by OSO ₃ );
(B) The olefin structural unit 45 represented by the general formula (I) 45
998.5 mol%, the acrylate structural unit represented by the general formula (II) 0-15 mol%, the general formula (V):

[0034]

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(Wherein R ¹ and R ³ are the same as above, m
Represents 0 or 1.) 0.5 to 5 mol% of an alkylmaleimide structural unit represented by the general formula (VI):

[0036]

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(Wherein R ¹ , R ⁴ , R ⁵ , R ⁶ , R ⁷ ,
X and m are the same as those described above, and a polyolefin resin having a weight average molecular weight of 1,000 to 50,000 (hereinafter, referred to as polyolefin resin B) linearly and irregularly composed of 1 to 35 mol% of a cationized maleimide structural unit represented by the following formula: A laminated polyolefin-based resin foam characterized in that a polyolefin-based resin foam layer containing at least one of the following is provided.

First, the polyolefin resin A and its intermediate will be described.

The ratio of the olefin structural unit represented by the general formula (I) in the polyolefin resin A is 45 to 9
8.5 mol%. When the proportion of the olefin structural unit is less than 45 mol%, the glass transition point of the polyolefin-based resin A becomes high, not only impairing the original flexibility of the polyolefin-based resin, but also reducing the number of Despite the presence of a large amount, the antistatic property is not so good, and if it exceeds 98.5 mol%, the antistatic property of the polyolefin resin A becomes too small.

In the olefin structural unit, R ¹ is a hydrogen atom or a methyl group, and these groups may be present in one molecule. The proportion of the olefin structural unit is preferably 85 to 97 mol% from the viewpoint of the balance between the antistatic property and the glass transition point.

The proportion of the acrylate structural unit represented by the general formula (II) in the polyolefin resin A is 0 to 15 mol%. The ratio of the acrylate structural unit is
If it exceeds 15 mol%, the softening point of the polyolefin resin A becomes low, and tack and stickiness occur.
In the present invention, when the acrylate structural unit is contained, toughness and impact resistance are imparted, which is preferable. In the present invention, the proportion of the acrylate structural unit is from 1 to 15 mol%, preferably from 3 to 7 from the viewpoint of the balance between the softening point and toughness and impact resistance.
Molar% is particularly preferred.

In the acrylate structural unit, R ²
Is an alkyl group having 1 to 4 carbon atoms. Specific examples of such R ^2, such as methyl group, ethyl group, n- propyl group, i- propyl, n- butyl group, etc. i- butyl group, and these groups coexist in one molecule May be. Among these groups, a methyl group and an ethyl group are particularly preferable for maintaining the softening point of the polyolefin resin A.

The ratio of the alkylmaleimide structural unit represented by the general formula (III) in the polyolefin resin A is 0.5 to 5 mol%. The alkylmaleimide structural unit has a property of improving the compatibility with other polyolefin resins, improves the flexibility of the polyolefin resin A, and imparts a property that the antistatic property is less dependent on environmental humidity. Things. When the proportion of the alkylmaleimide structural unit is less than 0.5 mol%, the compatibility with other polyolefin resins becomes poor, and when it exceeds 5 mol%, the antistatic property becomes small. Therefore, the proportion of the alkylmaleimide structural unit is preferably 1 to 3 mol% from the viewpoint of the balance between compatibility and antistatic properties.

In the alkylmaleimide structural unit represented by the general formula (III), R ³ is an alkyl group having 8 to 18 carbon atoms or an aryl group having 8 to 18 carbon atoms. A long-chain alkyl group having 16 to 18 carbon atoms is preferred from the viewpoint of compatibility with other olefin resins.

The proportion of the cationized maleimide structural unit represented by the general formula (IV) in the polyolefin resin A is from 1 to 35 mol%. When the proportion of the cationized maleimide structural unit is less than 1 mol%, the antistatic property becomes too small, and when it exceeds 35 mol%, the polyolefin resin A is blended with other polyolefin resins. This causes hygroscopicity and poor compatibility with the polyolefin resin. A preferred ratio of the cationized maleimide structural unit is 3 to 15 mol%.

In the cationized maleimide structural unit represented by the general formula (IV), specific examples of R ⁴ include, for example, an ethylene group, a propylene group, a hexamethylene group, and a neopentylene group. They may be present in one molecule. Among these groups, an ethylene group and a propylene group are preferable from the viewpoints of easiness of production of the polyolefin-based resin A and economy. R ⁵ and R ⁶ are an alkyl group having 1 to 4 carbon atoms, and specific examples of such R ⁵ and R ⁶ include, for example, a methyl group, an ethyl group, a propyl group, and a butyl group. They may be present in one molecule. Among these groups, a methyl group and an ethyl group are preferable in order to impart sufficient antistatic properties. R ⁷ is an alkyl group having 1 to 12 carbon atoms, an arylalkyl group having 6 to 12 carbon atoms, and 2 to 2 carbon atoms which may be substituted with an alkyl group.
An epoxy group of 4 or an alicyclic alkyl group having 6 to 12 carbon atoms. Among the above R ⁷ , in order to improve the heat resistance of the polyolefin resin A, a linear alkyl group or an arylalkyl group is preferable. Particularly preferred R ⁷ includes a methyl group and an ethyl group. The X
Is a halogen atom such as Cl, Br, I, etc., CH
₃ OSO ₃ or C ₂ H ₅ OSO ₃ , which are 1
It may be present in the molecule. Among them, Cl, CH ₃ OSO ₃ and C _3
2 H ₅ OSO ₃ is preferred.

The ratio of the alkylmaleimide structural unit represented by the general formula (III) to the cationized maleimide structural unit represented by the general formula (IV) (alkyl maleimide structural unit / cationized maleimide structural unit: molar ratio) Is 1/70 to 1/2, preferably 1/70, in order to impart sufficient antistatic property to the polyolefin resin A.
It is preferably from 70 to 1/43.

The polyolefin resin A has a weight average molecular weight of 1,000 to 50,000. The weight average molecular weight is 1000
If the molecular weight is less than the molecular weight, the molecular weight becomes too small and volatilizes when heated. If the molecular weight is more than 50,000, the viscosity upon melting becomes too large and workability deteriorates. The preferred weight average molecular weight is from 3000 to 35000.

The weight-average molecular weight referred to in the present specification refers to gel permeation chromatography (GP)
The monodisperse weight average molecular weight in terms of polystyrene measured in C).

The polyolefin resin A cannot be easily measured because it is hardly soluble in an ordinary gel permeation eluent such as tetrahydrofuran (THF) or xylene. It can be measured in accordance with Molecular Journal, Vol. 44, No. 2, pp. 139-141 (1987)).

The polyolefin resin A and its intermediate, an olefin structural unit represented by the general formula (I)
45 to 98.5 mol%, 0 to 15 mol% of the acrylate structural unit represented by the general formula (II), 0.5 to 5 mol% of the alkylmaleimide structural unit represented by the general formula (III), and
I):

[0052]

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(Wherein R ⁴ , R ⁵ and R ⁶ are the same as described above) having a weight average molecular weight of 1,000 to 50,000 which is linearly and irregularly composed of 1 to 35 mol% of a dialkylaminomaleimide structural unit represented by the formula: The copolymer (hereinafter, referred to as intermediate A) can be obtained, for example, by the following method.

First, the raw material of the intermediate A is not particularly limited. For example, benzene,
Using toluene or the like as a solvent, a radical polymerization initiator such as acrylate, maleic anhydride and benzoyl peroxide is dissolved, a predetermined amount of olefin is blown into the solution, and the mixture is reacted at 50 to 80 ° C. for 8 to 12 hours, and then autoclaved. Examples thereof include an olefin-acrylate-maleic anhydride copolymer obtained by a known method such as a method of pouring the contents therein into a large amount of a solvent such as ether. Here, the charged molar ratio of each monomer is
It is almost equal to the ratio of the structural unit of the target copolymer.

From the above raw materials, the polyolefin resin A
The method for producing the intermediate A is not particularly limited, but one example thereof will be described below.

The raw materials are, for example, benzene, toluene,
It is dissolved in an inert solvent such as an aromatic or aliphatic hydrocarbon such as xylene, cyclohexanone, decane, cumene or cymene, or a ketone, and the alkylene having 8 to 18 carbon atoms is formed to obtain a maleimide structure corresponding to the general formula (III). An amine is added and reacted at 130 to 180 ° C. to convert an acid anhydride group contained in the maleic anhydride structural unit into an alkylimide group.
Next, dialkylaminoalkylamine was added, and 130
By reacting at ~ 180 ° C, all of the remaining maleic anhydride structural units are converted to dialkylaminoalkylmaleimide structural units to obtain Intermediate A. The amount of the alkylamine to be used is 0.5 to 5 mol% of the alkylmaleimide unit, and is based on the acid anhydride group of the maleic anhydride structural unit.
It is 1.4 to 83 mol%, preferably 1.4 to 30 mol%. The dialkylaminoalkylamine is used in an amount of 100 to 150 mol%, preferably 100 to 110 mol%, based on the remaining maleic anhydride structural unit in order to make the dialkylaminoalkyl maleimide structural unit 1 to 35 mol%. It is.

The obtained intermediate A is further cation-modified with a known quaternizing agent such as alkyl halide, dialkyl sulfate, epichlorohydrin, etc., so that the dialkylaminoalkylmaleimide structural unit becomes a cationized maleimide structural unit. After conversion, the polyolefin resin A is obtained.

Next, the polyolefin resin B and its intermediate will be described.

As described above, the polyolefin-based resin B is an olefin structural unit 45 represented by the general formula (I).
998.5 mol%, acrylate structural unit represented by formula (II) 0-15 mol%, alkylmaleimide structural unit represented by formula (V) 0.5-5 mol%, and formula (VI)
Weight average molecular weight of 1000 linearly and irregularly composed of 1 to 35 mol% of a cationized maleimide structural unit represented by
Up to 50,000 polyolefin resins.

The ratio of the olefin structural unit represented by the general formula (I) in the polyolefin resin B is 45 to 9
8.5 mol%. When the ratio of the olefin structural unit is less than 45 mol%, the glass transition point of the polyolefin resin B becomes high, and when blended with the polyolefin resin, the inherent flexibility of the resin is impaired. Not
Despite the presence of many cationic groups, the antistatic property is not so good, and if it exceeds 98.5 mol%, the antistatic property of the polyolefin resin B becomes too small. In the olefin structural unit, R ¹ is a hydrogen atom or a methyl group, and these groups may be present in one molecule. The proportion of the olefin structural unit is preferably 85 to 97 mol% from the viewpoint of the balance between the antistatic property and the glass transition point.

The proportion of the acrylate structural unit represented by the general formula (II) in the polyolefin resin B is 0 to 15 mol%. The ratio of the acrylate structural unit is
When the amount exceeds 15 mol%, the softening point of the polyolefin resin B becomes low, and tackiness and stickiness occur when blended with the polyolefin resin. In the present invention, when the acrylate structural unit is contained, toughness and impact resistance are imparted when blended with a polyolefin-based resin, which is preferable. In the present invention, the proportion of the acrylate structural unit is from 1 to 15 from the viewpoint of the balance between the softening point, toughness and impact resistance.
It is particularly preferred that the content be from 3 to 7 mol%, especially from 3 to 7 mol%.

In the acrylate structural unit, R ²
Is an alkyl group having 1 to 4 carbon atoms. Specific examples of such R ² include the same as the acrylate structural unit of the polyolefin-based resin A.

The ratio of the alkylmaleimide structural unit represented by the general formula (V) in the polyolefin resin B is 0.5 to 5 mol%. The alkylmaleimide structural unit has a property of improving the compatibility with the polyolefin-based resin, improves the flexibility of the polyolefin-based resin B, and imparts a property of making the antistatic property less dependent on environmental humidity. It is. When the proportion of the alkylmaleimide structural unit is less than 0.5 mol%, the compatibility with the polyolefin resin becomes poor, and when it exceeds 5 mol%, the antistatic property becomes small. Therefore, the proportion of the alkylmaleimide structural unit is preferably 1 to 3 mol% from the viewpoint of the balance between compatibility and antistatic properties.

In the alkylmaleimide structural unit represented by the general formula (V), R ³ is an alkyl group having 8 to 18 carbon atoms or an aryl group having 8 to 18 carbon atoms. A long-chain alkyl group having 16 to 18 carbon atoms is preferred from the viewpoint of compatibility with other polyolefin-based resins.

The ratio of the cationized maleimide structural unit represented by the general formula (VI) in the polyolefin resin B is from 1 to 35 mol%. When the proportion of the cationized maleimide structural unit is less than 1 mol%, the antistatic property becomes too small, and when it exceeds 35 mol%, it becomes hygroscopic and the compatibility with the polyolefin resin becomes poor. become bad. A preferred ratio of the cationized maleimide structural unit is 3 to 15 mol%.

In the cationized maleimide structural unit represented by the general formula (VI), R ⁴ , R ⁵ , R ⁶ , R
Specific examples of ⁷ and X are the same as the cationized maleimide structural unit represented by the general formula (IV) of the polyolefin resin A.

The ratio of the alkylmaleimide structural unit represented by the general formula (V) to the cationized maleimide structural unit represented by the general formula (VI) (alkyl maleimide structural unit / cationized maleimide structural unit: molar ratio)
Is 1/70 to 1/2, preferably 1/70 to give the polyolefin resin B a sufficient antistatic property.
It is preferably 1/43.

The polyolefin resin B has a weight average molecular weight of 1,000 to 50,000. The weight average molecular weight is 1000
If the molecular weight is less than 1, the molecular weight becomes too small and the polyolefin resin B is blended with the polyolefin resin and volatilized when heated.If it exceeds 50,000, the polyolefin resin B is melted. The viscosity at the time of doing it becomes too large, and the workability becomes poor. The preferred weight average molecular weight is from 3000 to 35000.

The weight average molecular weight of the polyolefin resin B can be measured in the same manner as for the polyolefin resin A.

The polyolefin resin B and its intermediate (hereinafter referred to as intermediate B) can be obtained, for example, by the following method.

The method for producing the maleic anhydride graft-olefin-acrylate copolymer as a raw material of the intermediate B is not particularly limited. For example, a commercially available low molecular weight polypropylene-ethyl acrylate copolymer may be used. It is obtained by graft polymerization of maleic anhydride in the presence of an organic peroxide such as benzoyl peroxide.

By reacting the thus obtained olefin-acrylate copolymer onto which maleic anhydride has been grafted, an alkylamine and a dialkylaminoalkylamine in the same manner as in the method of the above-mentioned polyolefin resin A, 45 to 98.5 mol% of the olefin structural unit represented by the formula (I), 0 to 15 mol% of the acrylate structural unit represented by the general formula (II), 0.5 to 5 mol% of the alkylmaleimide structural unit represented by the general formula (V) And the general formula (VIII):

[0073]

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(Wherein R ¹ , R ⁴ , R ⁵ , R ⁶ and m
Are the same as described above), and an intermediate B having a weight average molecular weight of 1,000 to 50,000, which is linearly arranged and has a weight average molecular weight of 1,000 to 50,000, comprising 1 to 35 mol% of a dialkylaminomaleimide structural unit represented by the following formula:

The amount of the alkylamine to be used is from 1.4 to 83 with respect to the grafted maleic anhydride structural unit in order to make the alkylmaleimide structural unit 0.5 to 5 mol%.
Mol%, preferably 1.4 to 30 mol%. The dialkylamine is used in an amount of 100 to 150 mol%, preferably 100 to 110 mol%, based on the remaining maleic anhydride structural unit in order to make the dialkylaminoalkylmaleimide structural unit 1 to 35 mol%. is there.

Next, the polyolefin resin A is reacted with the same quaternizing agent as in the production of the polyolefin resin A, whereby the polyolefin containing the grafted cationized maleimide structural unit represented by the general formula (VI) is obtained. The base resin B is obtained.

The polyolefin resins A and B thus obtained each have excellent antistatic properties,
Moreover, it has an excellent property that the antistatic property is not greatly affected by the environmental humidity. The reason why the polyolefin-based resin has excellent properties is not clear, but the cationized maleimide structural unit contained in the polyolefin-based resins A and B takes in moisture in the air, and X ^- is ionized. This is considered to be caused by showing low electric resistance because of showing electric conductivity. On the other hand, since the alkylmaleimide structural units in the polyolefin-based resins A and B also have a long alkyl group in the side chain, the flexibility is improved, and the antistatic property exhibits excellent characteristics that the antistatic property is hardly dependent on environmental humidity. It is presumed to be a factor.

Further, in the present invention, since the cationic maleimide structural unit does not exhibit volatility even at high temperatures and is chemically incorporated in the polyolefin resin, there is no volatilization during processing. It is considered that no blocking or the like is caused after processing.

The polyolefin resin foam layer used in the present invention contains at least one of the polyolefin resins A and B. The polyolefin resins A and / or B are different from other polyolefin resins. They can be used in combination.

Examples of the other polyolefin resins include ethylene-containing resins having an ethylene content of 2 to 30% by weight.
Propylene copolymer, terpolymer obtained by further copolymerizing butene-1 with the ethylene-propylene copolymer, high-pressure low-density polyethylene, linear low-density polyethylene, linear ultra-low-density polyethylene, high-density Polyethylene, ethylene-vinyl acetate copolymer, saponified ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylate copolymer, ethylene- (meth) Acrylic acid-maleic anhydride terpolymer, ethylene- (meth) acrylate-maleic anhydride terpolymer, and the like. These resins may be used alone or in combination of two or more. Can be

When at least one of the polyolefin-based resins A and B is used in combination with the other polyolefin-based resin, the polyolefin-based resin A
And at least one of B is used in an amount of 100 parts (parts by weight, resin part) contained in the obtained polyolefin resin layer.
0.1 part or more, preferably 20 parts or more with respect to the same in the following, in order to impart antistatic properties.

The resin composition of the polyolefin resin foam used as the substrate in the present invention is not particularly limited, and may be appropriately selected and used according to the intended use of the obtained laminated polyolefin resin foam. Examples of the resin usable for the polyolefin resin foam include polypropylene, an ethylene-propylene copolymer having an ethylene content of 2 to 30% by weight, and a terpolymer obtained by further copolymerizing butene-1 with the ethylene-propylene copolymer. Various copolymers of propylene and other olefins such as copolymers, high-pressure low-density polyethylene, linear low-density polyethylene, linear ultra-low-density polyethylene, high-density polyethylene, and ethylene
-Vinyl acetate copolymer, saponified ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylate, ethylene-
(Meth) acrylic acid-maleic anhydride terpolymer, ethylene- (meth) acrylate-maleic anhydride terpolymer and the like. These resins may be used alone or in combination of two or more. Used.

The method for producing the polyolefin resin foam used in the present invention is not particularly limited, and a known production method can be applied. Specific examples thereof include, for example, a method of mixing a decomposable foaming agent with the foamable resin composition containing the polyolefin resin, introducing the mixture into an extruder, decomposing the foaming agent, and foaming the foamed resin composition. Is introduced into the extruder, and the evaporating solvent is press-fitted into the extruder to form a foam, a so-called extrusion foaming method. Heating, the peroxide compound is decomposed and cross-linked, the decomposition type foaming agent is decomposed and simultaneously decompressed and simultaneously released to form a foam, a so-called block foaming method, a foamable resin composition is introduced into an extruder, and formed into a sheet. After molding, a method of irradiating with an electron beam or adding a peroxide compound to form a crosslink, followed by heating and foaming may be used.

The expansion ratio and thickness of the polyolefin resin foam and the foam layer are not particularly limited, and may be appropriately selected according to the intended use of the obtained laminated polyolefin resin foam.

In the present invention, inorganic fillers such as calcium carbonate, talc, glass monofilament, etc., antioxidants, flame retardants, coloring agents, polyfunctional monomers, etc. are used as long as the object of the present invention is not impaired. And the like may be contained in the polyolefin resin foam layer and the polyolefin resin foam.

In the present invention, a known low molecular weight surfactant may be used in the polyolefin resin in an amount not exceeding 30 parts per 100 parts of the polyolefin resin. When the surfactant is used within a range not exceeding 30 parts, no bleeding from the obtained foam or foam layer is observed.

The method for laminating the polyolefin resin foam layer on the polyolefin resin foam is not particularly limited. For example, for example, a polyolefin resin foam serving as a base material is produced in advance. In addition, a method in which both surfaces of the polyolefin-based resin foam containing the polyolefin-based resin are heated to a melting temperature or higher with hot air to be fused and laminated, and the polyolefin-based resin foam is included during the production thereof, A method of directly laminating a polyolefin-based resin foam layer, specifically, a polyolefin-based resin foam layer having a thickness of 0.5 to 2 mm on one side or both sides of a portion to be a foamed resin serving as a base material in a molten state. A method of foaming after laminating the composite is given.

The thus obtained laminated polyolefin resin foam of the present invention may be further subjected to a corona discharge treatment on at least one side thereof to increase the surface wetting tension and to improve the adhesion to various water-soluble coating agents. it can. In addition, a coating agent layer is provided, and various skin materials, films, sheets, other foams, metal foils, papers, nonwoven fabrics made of natural fibers or synthetic fibers or synthetic leathers are laminated to form a composite, and then these are subjected to various kinds of processes. It can be formed by a method.

Next, the laminated polyolefin resin foam of the present invention will be described in more detail with reference to Examples.
The present invention is not limited to only such embodiments.

Example 1 As a foamable resin composition (A) for a polyolefin resin foam as a substrate, a high-pressure low-density polyethylene (density:
0.921 g / cm ³ , melt index: 3.7 g / 10 min,
(Particle size: 32 mesh pass) A mixture obtained by adding 10 parts of azodicarbonamide as a foaming agent to 100 parts and mixing.

The resin for the foam layer has the following formula:

[0092]

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85 mol% of an olefin structural unit represented by the formula:

[0094]

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5 mol% of an acrylate structural unit represented by the formula:

[0096]

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1 mol% of an alkylmaleimide structural unit represented by the following formula:

[0098]

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20 parts by weight of a polyolefin resin having a weight-average molecular weight of 39,400 and comprising 100 parts by weight of the same high-pressure low-density polyethylene resin as described above and 9 parts by mole of a cationized maleimide structural unit represented by The foamable resin composition (B) mixed with 6 parts of azodicarbonamide was used.

Next, two extruders were prepared, and each of the foamable resin compositions (A) and (B) was introduced into each extruder. Then, the extruder was introduced into a laminating apparatus equipped with a die complex, and melted and kneaded. And the thickness of the polyolefin resin foam layer is 1 mm,
The thickness of the foamable resin layer part that becomes the foam of the base material is 1.5 mm,
A molten composite continuous sheet having a width of 500 mm was formed.

The sheet was irradiated with an electron beam at 5 Mrad using an electron beam irradiator.
To give a crosslinked foamable laminated sheet.

The obtained cross-linked foamable laminated sheet was continuously introduced into a vertical hot-air foaming machine in a heating atmosphere of 230 ° C. to obtain a laminated foam. This laminated foam has an overall thickness of 4.2mm,
Total width is 1170mm, apparent foaming ratio is 20
The apparent expansion ratio was 13 times, and the thickness of the foam layer was 1.7 mm.

When the surface resistivity of the obtained laminated foam was measured according to the following method, it was found to be extremely small at 3.6 × 10 ¹¹ Ω, indicating that it had excellent antistatic properties.

Next, the obtained laminated foam was heated at 40 ° C. and 80%
After being left in an atmosphere of RH (relative humidity) for 7 days, the surface of the resin layer of the laminated foam was observed, and no stickiness due to bleed-out occurred. Printing was performed using the printing ink for printing, but there was no printing failure due to bleed-out.

Next, one surface of the obtained laminated foam was subjected to a corona discharge treatment to make the surface wetting tension 37 dyne / cm or more, thereby improving the adhesion to various coating agents.

Further, a coating agent layer is provided, and various skin materials, films, sheets, other foams, metal foil, paper,
After laminating a nonwoven fabric or a synthetic leather made of a natural fiber or a synthetic fiber to form a composite, it could be formed into a desired shape by various methods.

(Surface Specific Resistance) The laminated foam was cut into a piece of 10 cm × 10 cm, and left for 48 hours in a constant temperature and constant temperature room controlled at 20 ° C. and 60% RH for aging.

After the aging, the surface resistivity is measured in the atmosphere.

Measuring device: A super-insulation meter (VE-40 type) manufactured by Kawaguchi Electric Works, Ltd. connected to a room temperature measuring box (RC-02 type) Measurement conditions: Applied voltage 100 V Values measured with this device Is adopted.

The above surface resistivity is 1 × 10 ¹³ Ω.
Hereinafter, those having a charge half life of 3 minutes or less are considered to have antistatic properties.

Example 2 A low-density polyethylene (density: 0.923) was used as a foamable resin composition (A) for a polyolefin resin foam as a base material.
g / cm ³ , melt index: 1.2 g / 10 min, particle diameter: 32 mesh pass) A mixture obtained by adding 10 parts of azodicarbonamide as a foaming agent to 100 parts and mixing.

The resin for the foam layer has the following formula:

[0113]

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85 mol% of an olefin structural unit represented by the formula:

[0115]

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5 mol% of an acrylate structural unit represented by the formula:

[0117]

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9 mol% of an alkylmaleimide structural unit represented by the following formula:

[0119]

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A polyolefin resin having a weight-average molecular weight of 39,400 and having a weight average molecular weight of 39,400 and a foaming resin obtained by adding and mixing 4 parts of azodicarbonamide as a foaming agent. Composition (B) was used.

Next, the foamable resin composition (A) and
Using (B), a laminated foam was obtained in the same manner as in Example 1.
This laminated foam has an overall thickness of 3.0mm and an overall width of 1170m
m, the apparent expansion ratio of the foam as the base material was 20 times, the apparent expansion ratio of the foam layer was 6 times, and the thickness of the foam layer was 0.8 mm.

Next, as the physical properties of the obtained laminated foam, the surface resistivity was measured in the same manner as in Example 1, and the half-life of the charge, bleed-out and blocking shear force were examined according to the following methods. Table 1 shows the results.

(Half-Life of Electric Charge) A voltage of 10 KV was applied to the sample using a static honest meter (manufactured by Shishido Shokai) in the same atmosphere as when the surface resistivity was measured, and the applied electric charge was measured. Determine the decay rate as the half-life.

(Bleed-out) An additive-free biaxially stretched polypropylene film is superimposed on the surface of the foam, and is heated at 40 ° C. and 80% R
After being placed in an atmosphere of H for 7 days, the film is taken out, the film is peeled off from the foam, and the presence or absence of a deposit on the surface of the film is examined.

(Blocking shearing force) Two foams were superimposed over a width of 3 cm and a length of 4 cm, and 550 g of
And placed in an atmosphere of 40 ° C. and 80% RH for 7 days, and then the shear release force of the two foams is determined by a Shopper type tensile tester.

A shear peeling force of 1,000 g or less is considered to be acceptable. The weight is preferably 500 g or less.

Example 3 A low density polyethylene (density: 0.921 g / cm ³ , melt index:
(3.2 g / 10 min) What added 10 parts of azodicarbonamide as a foaming agent to 100 parts was used.

The resin for the foam layer has the following formula:

[0129]

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80 mol% of an olefin structural unit represented by the following formula:

[0131]

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1 mol% of an alkylmaleimide structural unit represented by the following formula:

[0133]

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30 parts of a polyolefin resin having a weight average molecular weight of 29,800 and having a weight average molecular weight of 29,800, and having a low density of polyethylene (density: 0.921 g / cm ³ , melt index:
The foaming composition (B) was prepared by adding and mixing 70 parts of 3.2 g / 10 min, particle diameter: 32 mesh pass) and 6 parts of azodicarbonamide as a foaming agent.

Using the obtained foamable resin compositions (A) and (B), two extruders heated to 110 to 170 ° C. were prepared, and the foamable resin compositions (A) and (B) were respectively prepared. (B)
After the foaming agent is gradually decomposed and kneaded until the foaming gas is evenly dispersed, the temperature is adjusted so as to have a viscosity suitable for foaming, and then the mixture is introduced into a device equipped with a combined die installation and laminated. Then, it was extruded from the die under atmospheric pressure and expanded to obtain a laminated foam. This laminated foam has a total thickness of 4.0mm
The total width was 1170 mm, the apparent foaming ratio of the foam as the base material was 25 times, the apparent foaming ratio of the foam layer was 13 times, and the thickness of the foam layer was 1.0 mm.

The physical properties of the obtained laminated foam were examined in the same manner as in Example 2. Table 1 shows the results.

Example 4 As a foamable resin composition (A) as a base material, a linear low-density polyethylene (density: 0.925 g / cm ³ , a melt index: 2 g / 10 minutes) and a low-density polyethylene (density: 0.923
g / cm ³ , melt index: 1.5 g / 10 min) in a weight ratio of 30:70.

The resin for the foam layer has the following formula:

[0139]

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80 mol% of an olefin structural unit represented by the following formula:

[0141]

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1 mol% of an acrylate structural unit represented by the following formula:

[0143]

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1 mol% of an alkylmaleimide structural unit represented by the following formula:

[0145]

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20 parts of a polyolefin resin having a weight-average molecular weight of 27,800 and consisting of 18 mol% of a cationized maleimide structural unit represented by the following formula:
80 parts of the same linear low-density polyethylene as used in the above was used. Next, two extruders heated to 110 to 125 ° C were prepared, and the foamable compositions (A) and (B) were introduced into each extruder, melted, and the volatile solvent was removed from the middle of the barrel of each extruder. Blow in the added state, knead until the volatile solvent is evenly dispersed in the resin, adjust the temperature so that it has a viscosity suitable for foaming, then introduce it to the production with a die complex equipment and laminate, The laminate was extruded from the die under atmospheric pressure and expanded to obtain a laminated foam. This laminated foam has a total thickness of 4.5m
m, the total width was 1170 mm, the apparent foaming ratio of the foam as the base material was 15 times, the apparent foaming ratio of the foam layer was 9 times, and the thickness of the foam layer was 1.25 mm.

The physical properties of the obtained laminated foam were examined in the same manner as in Example 2. Table 1 shows the results.

Example 5 As a foaming resin composition (A) serving as a base, 100 parts of an ethylene-propylene copolymer (ethylene content: 8% by weight, melt index: 2.3 g / 10 minutes) was used as a foaming agent. Azodicarbonamide 3 parts, dicumyl peroxide 1
Parts and 2 parts of divinylbenzene were used.

The resin for the resin layer has the formula:

[0150]

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88 mol% of an olefin structural unit represented by the following formula:

[0152]

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3 mol% of an acrylate structural unit represented by the formula:

[0154]

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1 mol% of an alkylmaleimide structural unit represented by the formula:

[0156]

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A polyolefin resin having a weight-average molecular weight of 37,800 and having a weight-average molecular weight of 37,800, which is composed of 8 mol% of cationized maleimide structural units represented by : 2.5 g / 10 min, particle size: 32 mesh pass) 40 parts and azodicarbonamide 2 as a foaming agent
Part, dicumyl peroxide 1 part and divinylbenzene 2 parts were used.

Next, a laminated foam was obtained in the same manner as in Example 1 except that dicumyl peroxide was decomposed and crosslinked, that is, the electron beam was not irradiated. The obtained laminated foam has a total thickness of 4.5 mm, a total width of 1170 mm,
The apparent expansion ratio of the foam as the base material was 5 times, the apparent expansion ratio of the foam layer was 3 times, and the thickness of the foam layer was 0.25 mm.

The physical properties of the obtained laminated foam were examined in the same manner as in Example 2. Table 1 shows the results.

Example 6 As a foamable resin composition (A) as a base material, a linear low-density polyethylene (density: 0.925 g / cm ³ , a melt index: 2 g / 10 minutes) and a low-density polyethylene (density: 0.923
g / cm ³ , melt index: 1.5 g / 10 min) in a weight ratio of 30:70.

The resin for the foam layer has the following formula:

[0162]

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80 mol% of an olefin structural unit represented by the following formula:

[0164]

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1 mol% of an acrylate structural unit represented by the formula:

[0166]

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1 mol% of an alkylmaleimide structural unit represented by the formula:

[0168]

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20 parts by weight of a polyolefin resin having a weight average molecular weight of 26,900 and linearly and irregularly arranged and comprising 19 mol% of a cationized maleimide structural unit represented by the following formula:
80 parts of the same linear low-density polyethylene as used in the above was used. Next, two extruders heated to 110 to 125 ° C. were prepared, foamable compositions (A) and (B) were introduced into each extruder, melted, and the volatile solvent was removed from the middle of the barrel of each extruder. Blow in the added state, knead until the volatile solvent is evenly dispersed in the resin, adjust the temperature so that it has a viscosity suitable for foaming, then introduce it to the production with a die complex equipment and laminate, The laminate was extruded from the die under atmospheric pressure and expanded to obtain a laminated foam. This laminated foam has a total thickness of 4.5m
m, the overall width was 1170 mm, the apparent foaming ratio of the foam as the base material was 17 times, the apparent foaming ratio of the foam layer was 13 times, and the thickness of the foam layer was 1.25 mm.

The physical properties of the obtained laminated foam were examined in the same manner as in Example 2. Table 1 shows the results.

Example 7 A laminated foam was obtained in the same manner as in Example 1 except that 10 parts of the 20 parts of the polyolefin resin used in Example 1 were changed to the polyolefin resin used in Example 6. This laminated foam has an overall thickness of 4.5 mm, an overall width of 1170 mm, an apparent expansion ratio of the base foam of 25 times, an apparent expansion ratio of the foam layer of 15 times, and the thickness of the foam layer. It was 1.25 mm.

The physical properties of the obtained laminated foam were examined in the same manner as in Example 2. Table 1 shows the results.

[0173]

[Table 1]

Comparative Example 1 Polypropylene (melt index: 2.5 g / 10 minutes,
(Particle size: 32 mesh pass) 99 parts, 1 part of stearic acid monoglyceride as an antistatic agent, 5 parts of azodicarbonamide as a foaming agent, and 2 parts of divinylbenzene are mixed to obtain a foamable composition (B) for a foam layer. I got it.

Ethylene-propylene copolymer (ethylene content: 5% by weight, melt index: 1.2 g / 10 min)
100 parts, 3 parts of azodicarbonamide as a foaming agent and 2 parts of divinylbenzene were mixed to obtain a foamable composition (A) for a foam as a base material.

Next, the obtained foamable composition (A) and
Using (B), a laminated foam was obtained in the same manner as in Example 1.

The physical properties of the obtained laminated foam were examined in the same manner as in Example 2. Table 2 shows the results.

Comparative Example 2 Polypropylene (melt index: 2.5 g / 10 minutes,
Particles: 32 mesh pass) 99.2 parts, formula as antistatic agent:

[0179]

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Betaine type amphoteric surfactant represented by the formula:
Eight parts, 3 parts of azodicarbonamide as a foaming agent and 2 parts of divinylbenzene were mixed to obtain a foamable resin composition (B) for a foam layer.

A foamable composition for a foam as a base material was prepared by mixing 100 parts of the same ethylene-propylene copolymer as used in Comparative Example 1, 1 part of azodicarbonamide as a foaming agent and 2 parts of divinylbenzene. (A)

Next, the obtained foamable composition (A) and
Using (B), a laminated foam was obtained in the same manner as in Example 1.

The physical properties of the obtained laminated foam were examined in the same manner as in Example 2. Table 2 shows the results.

Comparative Example 3 Low density polyethylene (density: 0.921 g / cm ³ , melt index: 3.2 g / 10 min, particle size: 32 mesh pass)
98.5 parts and stearic acid monoglyceride as antistatic agent with formula:

[0185]

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A betaine-type amphoteric surfactant represented by the formula (1) was mixed at a weight ratio of 1: 1 and 1.5 parts were mixed to obtain a foamable resin composition (B) for a foam layer.

A foamable resin composition for a foam as a base material using the same low-density polyethylene as that used in Example 3.
(A)

Using the foamable resin compositions (A) and (B) thus obtained, a laminated foam was obtained in the same manner as in Example 4.

The physical properties of the obtained laminated foam were examined in the same manner as in Example 2. Table 2 shows the results.

Comparative Example 4 95 parts of an ethylene-propylene copolymer having an ethylene content of 5% by weight (melt index: 1.2 g / 10 min, particle diameter: 32 mesh pass), sodium dodecylbenzenesulfonate and polyethylene glycol as antistatic agents Were mixed in a 1: 1 weight ratio, 10 parts of azodicarbonamide as a foaming agent and 2 parts of divinylbenzene were mixed to obtain a foamable composition (B) for a foam layer.

The same polypropylene used in Example 5
100 parts and 8 parts of azodicarbonamide as blowing agent,
2 parts of divinylbenzene were mixed to obtain a foamable composition (A) for a foam as a base material.

The foamable composition (A) obtained and
(B) was obtained in the same manner as in Example 1 to obtain a laminated foam.

The physical properties of the obtained laminated foam were examined in the same manner as in Example 2. Table 2 shows the results.

Comparative Example 5 Polypropylene (melt index: 2.5 g / 10 minutes,
Particle size: 32 mesh pass) 99.2 parts, 0.8 parts of stearyl diethanolamine as an antistatic agent, 3 parts of azodicarbonamide, 1 part of dicumyl peroxide and 2 parts of divinylbenzene as a foaming agent are mixed to form a foaming layer for foaming. A composition (B) was obtained.

Further, 100 parts of the polypropylene and 2 parts of azodicarbonamide as a foaming agent, 1 part of dicumyl peroxide, and 2 parts of divinylbenzene were mixed to prepare a foamable composition (A) for a foam as a base material. I got it.

Next, the obtained foamable composition (A) and
A laminated foam was obtained in the same manner as in Example 1, except that dicumyl peroxide was decomposed and crosslinked using (B), that is, the electron beam was not irradiated.

The physical properties of the obtained laminated foam were examined in the same manner as in Example 2. Table 2 shows the results.

[0198]

[Table 2]

From the results shown in Table 1, the laminated polyolefin resin foam of the present invention has a surface resistivity of 1 × 10 ¹³ Ω or less as an index of antistatic property and a half-life of electric charge of 180 seconds or less. It can be seen that the laminate foam is excellent and does not bleed out of the laminate foam of the antistatic component from the foam layer, and thus has excellent antistatic properties without blocking.

On the other hand, the laminated foams obtained in Comparative Examples 1 to 5 used a conventional comparatively low molecular weight surfactant-type antistatic agent. If the antistatic property is intended to be satisfied, the antistatic agent bleeds out of the foam, so that there is a disadvantage that blocking occurs.

As described above, the laminated polyolefin-based resin foam of the present invention has excellent antistatic properties, has no bleed-out of the antistatic agent, and does not cause blocking. It can be seen that it can be suitably used in fields where it is necessary.

[0202]

The laminated polyolefin resin foam of the present invention has no bleed-out and exhibits extremely excellent antistatic properties, so that there is no adhesion of dust and no shock to the human body due to electrostatic discharge. Therefore, it is a laminated foam excellent in handling properties.

Claims (1)

(57) [Claims] [Claim 1] General formula (I): (Wherein R ¹ represents a hydrogen atom or a methyl group) 45 to 98.5 mol% of an olefin structural unit represented by the following general formula (II): (Wherein R ² represents an alkyl group having 1 to 4 carbon atoms) 0 to 15 mol% of an acrylate structural unit represented by the following general formula (III): (Wherein R ³ represents an alkyl group having 8 to 18 carbon atoms or an aryl group having 8 to 18 carbon atoms), and 0.5 to 5 mol% of an alkylmaleimide structural unit represented by the following general formula (IV): (Wherein, R ⁴ is an alkylene group having 2 to 8 carbon atoms, R ⁵ and R ⁶ are alkyl groups having 1 to 4 carbon atoms, R ⁷ is an alkyl group having 1 to 12 carbon atoms, and 6 to 12 carbon atoms. An arylalkyl group, having 2 to 2 carbon atoms which may be substituted with an alkyl group;
An epoxy group of 4 or an alicyclic alkyl group having 6 to 12 carbon atoms,
X is a halogen atom, CH ₃ OSO ₃ or C ₂ H ₅ OS
O ₃ are shown) cationized maleimide structural units 1 to 35 mol% linear irregularly arranged with weight-average molecular weight from 1,000 to 50,000 polyolefin resins consisting represented by, and the general formula (I): 5] (Wherein R ¹ is as defined above) 45 to 98.5 mol% of an olefin structural unit represented by the following general formula (II): (Wherein R ² is as defined above) 0 to 15 mol% of an acrylate structural unit represented by the following general formula (V) (Wherein, R ¹ and R ³ are the same as above, and m is 0 or 1)
The alkylmaleimide structural unit represented by 0.5)
To 5 mol% and the general formula (VI): (Wherein, R ¹ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , X and m are the same as those described above), and are linearly and irregularly composed of 1 to 35 mol% of cationized maleimide structural units. A laminated polyolefin resin foam comprising a polyolefin resin foam layer containing at least one polyolefin resin having a weight average molecular weight of 1,000 to 50,000.