JPH05194775A - Polyolefin resin foam - Google Patents

Abstract

PURPOSE:To obtain the title foam excellent in antistatic properties, surface wettability, and printability by using a polyolefin resin comprising specific resin comprising specfic olefin units, acrylate units, alkylmaleimide units, and cationized maleimide units. CONSTITUTION:A foam is produced from a polyolefin resin comprising 45-98.5-mol% olefin units of formula I (wherein R<1> is H or methyl), 0-15mol% acrylate units of formula II (wherein R<2> is 1-4C alkyl), 0. 5-5mol% alkylmaleimide units of formula II (wherein R<3> is 8-18C alkyl or 8-18C aryl), and 1-35mol% cationized maleimide units of formula IV (wherein R<4> is 2-8C alkylene; R<5> and R<6> are each 1-4C alkyl; R<7> is 1-12C alkyl, 6-12C aralkyl; etc.; and X is halogen, CH3OSO3, etc., arranged linearly and randomly and having a wt.-average mol.wt. of 1,000-50,000.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyolefin resin foam. More specifically, the present invention relates to a polyolefin resin foam having excellent antistatic properties and surface wettability, which can be suitably used as materials such as daily necessities such as bath mats, packings, heat insulating materials, automobile interior materials and the like.

[0002]

2. Description of the Related Art Generally, a foam made of a polyolefin resin, particularly a polyethylene resin or a polypropylene resin, has a large hydrophobicity, so that static electricity is remarkably generated, dust is attached to the foam, or static electricity is discharged. There is a problem such as giving a shock to the human body. Also, since the surface water wettability is poor due to the large hydrophobicity, when the surface of the foam is coated with an adhesive or a printing ink, it is not applied uniformly, causing a so-called cissing phenomenon. There is a problem that the adhesive strength of the adhesive is small.

Therefore, conventionally, in order to impart antistatic properties to foams, a method of adding an anionic, cationic or amphoteric surfactant, or a method of previously adding a polyolefin resin to JP-A-62-121717 is described. Resin and Japanese Fairness 1-
The method of adding the resin described in Japanese Patent No. 29820 is adopted.

However, in the method of adding the surfactant, the surfactant has a molecular weight of at most 500-.
Since it is relatively small at around 600, it volatilizes during the production of the foam, and bleeds out over time after forming the foam, contaminating the surface of the foam, causing blocking, and bonding. However, there is a problem that it deteriorates the printability, printability and vapor deposition property. Further, in the method of adding the specific resin, since the resin is not a polyolefin-based resin, the buffering property of the polyolefin-based resin foam when formed into a foam is reduced, and further, such a resin is a polyolefin resin. Since the compatibility with the resin is poor,
There are problems that voids are generated in the case of forming a foam, the expansion ratio is reduced due to the escape of foaming gas, and that the formability of the foam is poor.

On the other hand, as a method for improving the surface wettability of a polyolefin resin foam, generally, a method of subjecting it to corona discharge treatment, a copolymer of ethylene and a vinyl monomer having a specific functional group, or a grafted copolymer is used. A method using a polymer or the like is adopted. However, in the method of performing the corona discharge treatment, there is a problem in terms of so-called durability, which shows a change with time after the treatment. In the method using the above copolymer, the surface wettability of the foam (surface wetting tension)
Since it is necessary to add a large amount of copolymer in order to practically increase the value to 37 dyne / cm or more, there is a problem that the cost becomes high and the heat resistance is lowered due to the low melting point of the copolymer. ..

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and is excellent in antistatic property and surface wettability, and is free from bleeding and blocking. Moreover, it is an object of the present invention to provide a polyolefin resin foam excellent in printability and the like.

[0007]

The present invention has the general formula (I):

[0008]

[Chemical 9]

(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):

[0010]

[Chemical 10]

An acrylate structural unit represented by the formula (wherein R ² represents an alkyl group having 1 to 4 carbon atoms) in an amount of 0 to 15 mol%, and a general formula (III):

[0012]

[Chemical 11]

(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 and the general formula (IV):

[0014]

[Chemical 12]

(In the formula, R ⁴ is an alkylene group having 2 to 8 carbon atoms, R ⁵ and R ⁶ are each an alkyl group having 1 to 4 carbon atoms, R ⁷ is an alkyl group having 1 to 12 carbon atoms, and 6 carbon atoms. 12 arylalkyl group, alicyclic alkyl group of the epoxy group or C6-12 2 to 4 carbon atoms which may be substituted by an alkyl group, X is a halogen atom, CH ₃ OSO ₃ or C ₂ H ₅ Of the cationized maleimide structural unit represented by OSO ₃ ) having a weight average molecular weight of 1000 to 50000 and having a weight average molecular weight of 1000 to 50000, and the general formula (I):

[0016]

[Chemical 13]

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

[0018]

[Chemical 14]

An acrylate structural unit represented by the formula (wherein R ² is the same as above) 0 to 15 mol%, the general formula (V):

[0020]

[Chemical 15]

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

[0022]

[Chemical 16]

(Wherein R ¹ , R ⁴ , R ⁵ , R ⁶ , R ⁷ ,
X and m are the same as those described above), and contain at least one polyolefin resin having a weight average molecular weight of 1000 to 50,000 linearly irregularly arranged and composed of 1 to 35 mol% of a cationized maleimide structural unit. The present invention relates to a polyolefin resin foam.

[0024]

FUNCTION AND EXAMPLE As described above, the polyolefin resin foam of the present invention comprises (A) the general formula (I):

[0025]

[Chemical 17]

(In the formula, 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):

[0027]

[Chemical 18]

An acrylate structural unit represented by the formula (wherein R ² represents an alkyl group having 1 to 4 carbon atoms) in an amount of 0 to 15 mol%, and a general formula (III):

[0029]

[Chemical 19]

(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 and the general formula (IV):

[0031]

[Chemical 20]

(Wherein R ⁴ is an alkylene group having 2 to 8 carbon atoms, R ⁵ and R ⁶ are each an alkyl group having 1 to 4 carbon atoms, R ⁷ is an alkyl group having 1 to 12 carbon atoms, and 6 carbon atoms. 12 arylalkyl group, alicyclic alkyl group of the epoxy group or C6-12 2 to 4 carbon atoms which may be substituted by an alkyl group, X is a halogen atom, CH ₃ OSO ₃ or C ₂ H ₅ OSO ₃ consisting cationized maleimide structural units to 35 mole% represented by the illustrated) linearly arranged irregularly with weight-average molecular weight from 1,000 to 50,000 polyolefin resin (hereinafter, referred to as the polyolefin resin a), and
(B) the olefin structural unit represented by the general formula (I) 45
~ 98.5 mol%, the acrylate structural unit represented by the general formula (II) 0 to 15 mol%, the general formula (V):

[0033]

[Chemical 21]

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

[0035]

[Chemical formula 22]

(Wherein R ¹ , R ⁴ , R ⁵ , R ⁶ , R ⁷ ,
X and m are the same as the above), and a polyolefin resin having a weight average molecular weight of 1000 to 50,000 and linearly irregularly arranged of 1 to 35 mol% of a cationized maleimide structural unit (hereinafter referred to as polyolefin resin B) A polyolefin resin foam containing at least one of the above.

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

The proportion of the olefin structural unit represented by the general formula (I) in the polyolefin resin A is 45 to 9
It is 8.5 mol%. When the proportion of the olefin structural unit is less than 45 mol%, the glass transition point of the polyolefin resin A becomes high, and not only the original flexibility of the polyolefin resin is impaired, but also a cationic group is added. The antistatic property is not so good in spite of the existence of many, and when it exceeds 98.5 mol%, the antistatic property of the polyolefin resin A becomes too small.

In the above olefin structural unit, R ¹ is a hydrogen atom or a methyl group, and these groups may be mixed in one molecule. The proportion of the olefin structural unit is preferably 85 to 97 mol% from the viewpoint of antistatic property and balance of 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
When 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 1 to 15 mol%, especially 3 to 7 from the viewpoint of the balance between the softening point and the toughness and impact resistance.
It is particularly preferable that the content is mol%.

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

The proportion 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 the property of improving the compatibility with the polyolefin-based resin, improves the flexibility of the polyolefin-based resin A, and imparts the property of making the antistatic property less dependent on the environmental humidity. Is. 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 poor. Therefore, the proportion of the alkylmaleimide structural unit, from the viewpoint of the compatibility and antistatic balance,
It is preferably 1 to 3 mol%.

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. From the viewpoint of compatibility with other polyolefin resins, long-chain alkyl groups having 16 to 18 carbon atoms are preferable.

The proportion of the cationized maleimide structural unit represented by the general formula (IV) in the polyolefin resin A is 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 has hygroscopicity, and The compatibility with the polyolefin resin becomes poor. A preferable ratio of the cationized maleimide structural unit is 3 to
It is 15 mol%.

In the cationized maleimide structural unit represented by the general formula (IV), specific examples of R ⁴ include, for example, ethylene group, propylene group, hexamethylene group, neopentylene group and the like. They may be mixed in one molecule. Among these groups, ethylene group and propylene group are preferable from the viewpoint of easiness of production of the polyolefin resin A, economy, and the like.

R ⁵ and R ⁶ are alkyl groups having 1 to 4 carbon atoms, and specific examples of R ⁵ and R ⁶ include methyl group, ethyl group, propyl group and butyl group. The groups may be mixed 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, an epoxy group having 2 to 4 carbon atoms which may be substituted with an alkyl group, or an alkyl group having 6 to 12 carbon atoms. It is an alicyclic alkyl group. 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.

X is, for example, a halogen atom such as Cl, Br or I, CH ₃ OSO ₃ or C ₂ H ₅ OSO ₃
And these may be mixed in one molecule. Among these, from the viewpoint of antistatic property, Cl, CH
₃ OSO ₃ and C ₂ H ₅ OSO ₃ are preferred.

The ratio of the alkyl maleimide 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, especially 1/70 to 1 in order to impart sufficient antistatic properties to the polyolefin resin A.
It is preferably 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
When it is less than the above range, the molecular weight becomes too small to be volatilized when heated, and when it exceeds 50,000, the viscosity at the time of melting becomes too large, resulting in poor workability. The preferred weight average molecular weight is 3000 to 35000.

The term "weight average molecular weight" as used herein means gel permeation chromatography (GP).
The monodisperse polystyrene-equivalent weight average molecular weight measured in C).

The polyolefin resin A used in the present invention is hardly soluble in an eluent for normal gel permeation, such as tetrahydrofuran (THF) and xylene, and therefore cannot be easily measured. (Kinukawa, Journal of Polymer Science, Vol. 44, No. 2, 139-141 (198
7 years))).

The polyolefin-based resin A and an olefin structural unit represented by the general formula (I) which is an intermediate thereof.
45-98.5 mol%, acrylate structural unit represented by general formula (II) 0-15 mol%, alkylmaleimide structural unit represented by general formula (III) 0.5-5 mol% and general formula (VI
I):

[0054]

[Chemical formula 23]

(Wherein R ⁴ , R ⁵ and R ⁶ are the same as defined above), the dialkylaminomaleimide structural units having a weight average molecular weight of 1000 to 50000, arranged linearly and irregularly, in an amount of 1 to 35 mol%. 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, and for example, benzene in an autoclave,
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 adding a large amount of the content in a solvent such as ether. Here, the charged molar ratio of each monomer is
It is almost equal to the ratio of structural units of the target copolymer.

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

For example, benzene, toluene,
It is dissolved in an aromatic or aliphatic hydrocarbon such as xylene, cyclohexanone, decane, cumene or cymene, or an inert solvent such as a ketone, and first, an alkyl group having 8 to 18 carbon atoms is obtained to obtain a maleimide structure corresponding to the general formula (III). An amine is added and reacted at 130 to 180 ° C. to convert the acid anhydride group contained in the maleic anhydride structural unit into an alkylimide group. Then add dialkylaminoalkylamine,
All of the remaining maleic anhydride structural units are converted to dialkylaminoalkylmaleimide structural units by reacting at 130 to 180 ° C. to give Intermediate A. The amount of the alkylamine used is 1.4 to 83 mol%, preferably 1.4 to 30% mol based on the acid anhydride group of the maleic anhydride structural unit in order to make the alkyl maleimide structural unit 0.5 to 5 mol%. is there. The amount of the dialkylaminoalkylamine used is 100 to 150 mol%, preferably 100 to 1 mol% with respect to the remaining maleic anhydride structural unit in order to adjust the dialkylaminoalkylmaleimide structural unit to 1 to 35 mol%.
It is 10 mol%. The resulting intermediate A is further cation-modified with a known quaternizing agent such as alkyl halide, dialkyl sulfate, and epichlorohydrin to convert the dialkylaminoalkylmaleimide structural unit into a cationized maleimide structural unit, The polyolefin resin A is obtained.

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

As described above, the polyolefin resin B is an olefin structural unit 45 represented by the general formula (I).
To 98.5 mol%, an acrylate structural unit represented by the general formula (II) 0 to 15 mol%, an alkylmaleimide structural unit represented by the general formula (V) 0.5 to 5 mol%, and a general formula (VI)
A cationized maleimide structural unit represented by 1 to 35 mol% of linearly irregularly arranged weight average molecular weight of 1000
It is a polyolefin resin of up to 50,000.

The proportion of the olefin structural unit represented by the general formula (I) in the polyolefin resin B is 45 to 9
It is 8.5 mol%. When the proportion of the olefin structural unit is less than 45 mol%, the glass transition point of the polyolefin resin B becomes high and not only the original flexibility of the resin is impaired, but also many cationic groups are present. However, if the antistatic property is not so good and if it exceeds 98.5 mol%, the polyolefin resin B
The antistatic property of becomes too small. In the olefin structural unit, R ¹ is a hydrogen atom or a methyl group, and these groups may be mixed in one molecule. The proportion of the olefin structural unit is preferably 85 to 97 mol% from the viewpoint of antistatic property and balance of 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 it exceeds 15 mol%, the softening point of the polyolefin resin B becomes low, and tack and stickiness occur.
When the acrylate structural unit is contained in the polyolefin resin, it is preferable because it gives toughness and impact resistance when blended with other polyolefin resins. In the polyolefin resin, the ratio of the acrylate structural unit is
From the viewpoint of the balance between the softening point and toughness and impact resistance,
It is particularly preferably 1 to 15 mol%, especially 3 to 7 mol%.

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

The proportion 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 the property of improving the compatibility with other polyolefin-based resins, improves the flexibility of the polyolefin-based resin B, and imparts the property of making the antistatic property less dependent on environmental humidity. To do. 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 poor. Therefore, the proportion of the alkylmaleimide structural unit is preferably 1 to 3 mol% in terms of the compatibility and antistatic property.

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 preferable from the viewpoint of compatibility with other polyolefin resins.

The proportion of the cationized maleimide structural unit represented by the general formula (VI) in the polyolefin resin B is 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%, hygroscopicity occurs and the phase relative to other polyolefin-based resins. The solubility becomes poor. A preferable 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 and R
Specific examples of ⁷ and X include 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) (alkylmaleimide structural unit / cationized maleimide structural unit: molar ratio)
Is 1/70 to 1/2, especially 1/70 to 1 in order to impart sufficient antistatic property to the polyolefin resin B.
It is preferably 1/43.

The weight average molecular weight of the polyolefin resin B is 1,000 to 50,000. The weight average molecular weight is 1000
When the amount is less than the above, the molecular weight becomes too small to be volatilized when the polyolefin resin B is heated, and when it exceeds 50,000, the viscosity when melted becomes too large, resulting in poor workability. become bad. The preferred weight average molecular weight is 3000 to 35000.

The weight average molecular weight of the polyolefin resin B can be measured in the same manner as 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, which is a raw material of the intermediate B, is not particularly limited. For example, a commercially available low molecular weight polypropylene-ethyl acrylate copolymer is used. Obtained by graft polymerization of maleic anhydride in the presence of an organic peroxide such as benzoyl peroxide.

The olefin-acrylate copolymer grafted with maleic anhydride thus obtained is reacted with an alkylamine and a dialkylaminoalkylamine in the same manner as in the case of the polyolefin resin A, to give 45 to 98.5 mol% of olefin structural unit represented by formula (I), 0 to 15 mol% of acrylate structural unit represented by general formula (II), 0.5 to 5 mol% of alkylmaleimide structural unit represented by general formula (V) , And the general formula (VIII):

[0074]

[Chemical formula 24]

(Wherein R ¹ , R ⁴ , R ⁵ , R ⁶ and m
Is the same as the above), and an intermediate B having a weight average molecular weight of 1000 to 50,000 and linearly and irregularly arranged and composed of 1 to 35 mol% of a dialkylaminomaleimide structural unit is obtained.

The amount of the alkylamine used is 1.4 to 83 relative to the grafted maleic anhydride structural unit so that the amount of the alkylmaleimide structural unit is 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 adjust the dialkylaminoalkylmaleimide structural unit to 1 to 35 mol%. is there.

Then, by reacting with the same quaternizing agent as in the case of producing the polyolefin resin A, the grafted cationized maleimide structural unit represented by the general formula (VI) of the present invention is contained. Polyolefin resin B is obtained.

The polyolefin resins A and B thus obtained each have an excellent antistatic property,
Moreover, it has an excellent property that the antistatic property is not so much influenced by the environmental humidity. Thus, the reason why the polyolefin resins A and B have excellent properties is not clear, but the cationized maleimide structural unit contained in the polyolefin resins A and B takes in water in the air, and X ⁻ is It is considered that this is due to the fact that it exhibits low electrical resistance because it ionizes and exhibits electrical conductivity. On the other hand, since the alkylmaleimide structural units in the polyolefin resins A and B also have long alkyl groups in their side chains, flexibility is improved, and antistatic properties are excellently independent of environmental humidity. It is speculated that this is a factor.

Further, in the above polyolefin resin, the cationized maleimide structural unit does not exhibit volatility even at high temperature, and since it is chemically incorporated into the above polyolefin resin, it is volatilized during processing. Therefore, it is considered that blocking does not occur after processing.

The polyolefin resin foam of the present invention is
The resin contains at least one of the polyolefin resins A and B, and the polyolefin resins A and B may be used alone or in combination, and other polyolefin resins may be mixed and used. Good.

Examples of the other polyolefin resin include ethylene 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) acrylic acid ester copolymer, ethylene- (meth ) Acrylic acid-maleic anhydride terpolymer, ethylene- (meth) acrylic acid ester-maleic anhydride terpolymer, etc. may be mentioned, and these resins may be used alone or in combination of two or more. Used.

When the polyolefin-based resin and the other polyolefin-based resin are used in combination, the amount of at least one of the polyolefin-based resin A and the polyolefin-based resin B used is the obtained polyolefin-based resin foam. In order to impart antistatic property and surface wettability to the obtained polyolefin-based resin foam, 0.1 part or more, preferably 20 parts or more based on 100 parts (parts by weight, the same below) of the resin component contained in Is desirable.

In the present invention, as long as the object of the present invention is not impaired, for example, inorganic fillers such as calcium carbonate, talc, and glass single fiber, antioxidants, flame retardants, colorants, polyfunctional monomers, etc. Various auxiliaries, etc. may be included in the polyolefin resin foam of the present invention.

Further, in the present invention, a known low molecular weight surfactant is used in an amount of 30 parts per 100 parts of the polyolefin resin.
You may use it in the range which does not exceed a part. Thus, when the surfactant is used within the range not exceeding 30 parts, no bleeding from the obtained foam is observed.

The method for producing the polyolefin resin foam of the present invention is not particularly limited, and known production methods can be applied. As a specific example thereof, for example, a decomposable foaming agent is mixed with a foamable resin composition containing the polyolefin resin and introduced into an extruder,
A method of decomposing a foaming agent to foam, a so-called extrusion foaming method in which the foamable resin composition is introduced into an extruder, and an evaporative solvent is further pressed into the extruder to foam.
The foamable resin composition is filled in a mold together with a mixture of a decomposable foaming agent and a peroxide compound and heated under pressure to decompose the peroxide compound and crosslink, and further decompose the decomposable foaming agent to release the pressure at the same time. So-called block foaming method to form a foam, a method of introducing a foamable resin composition into an extruder and molding it into a sheet, then irradiating it with an electron beam or adding a peroxide compound to crosslink it, and heat foaming it. can give.

The thus obtained foam of the present invention can be further subjected to corona discharge treatment on at least one side to increase the surface wetting tension and improve the adhesiveness to various water-soluble coating agents. In addition, a coating agent layer is provided, and various skin materials, films, sheets, other foams,
After metal foil, paper, nonwoven fabric made of natural fibers or synthetic fibers or synthetic leather is laminated to form a composite, these can be molded by various methods.

Next, the polyolefin resin foam of the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1 Formula:

[0089]

[Chemical 25]

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

[0091]

[Chemical formula 26]

5 mol% of an acrylate structural unit represented by:

[0093]

[Chemical 27]

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

[0095]

[Chemical 28]

A polyolefin resin having a weight average molecular weight of 37800 and having a linearly irregular arrangement of 9 mol% of a cationized maleimide structural unit represented by: Polyethylene (density: 0.921 g / cm ³ , melt index: 3.7 g /
10 minutes, particle size: 32 mesh pass) 100 parts mixed resin 10
10 parts of azodicarbonamide as a foaming agent was added to 0 part and mixed to obtain a foamable resin composition.

Next, the foamable resin composition thus obtained was treated with 120-
It was introduced into an extruder heated to 130 ° C., melted and kneaded to form a molten continuous sheet having a thickness of 1.5 mm and a width of 500 mm. This sheet was irradiated with an electron beam of 5 Mrad with an electron beam irradiator to be crosslinked to obtain a crosslinked foamable sheet.

The crosslinked foamable sheet thus obtained was continuously introduced into a vertical hot air foaming machine having a heating atmosphere of 230 ° C. to obtain a foam. This foam has an overall thickness of 3.1 mm and an overall width of 1170 m.
m, apparent expansion ratio was 20 times.

The surface resistivity of the obtained foam was examined by the following method, and it was found that it was extremely small at 1.6 × 10 ¹⁰ Ω and had excellent antistatic properties.

Next, the obtained foam is treated at 40 ° C. and 80% RH.
The surface of the foam was observed after leaving it in an atmosphere of (relative humidity) for 7 days. No stickiness was observed, and the surface of the foam was printed with a printing ink for polypropylene. There was no print failure due to out.

Next, one side of the obtained foam was subjected to corona discharge treatment to have a surface wetting tension of 45 dyne / cm or more, and the adhesiveness with various coating agents could be improved.

Further, by providing a coating agent layer, various skin materials, films, sheets, other foams, metal foils, papers,
Nonwoven fabrics or synthetic leathers made of natural fibers or synthetic fibers were laminated to form a composite, which was then formed into a desired shape by various methods.

(Surface specific resistance) The foamed body is cut into a size of 10 cm x 10 cm and left in a constant temperature and humidity chamber controlled at 20 ° C and 60% RH for 48 hours for aging.

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

Measuring instrument: Ultra-insulator (VE-40 type) manufactured by Kawaguchi Electric Co., Ltd. and room temperature measuring box (RC-02 type) connected Measuring condition: Applied voltage 100V adopt.

The surface resistivity is 1 × 10 ¹³ Ω
Hereinafter, the one having a charge half-life of 3 minutes or less is assumed to have antistatic properties.

Example 2 Instead of the high-pressure low-density polyethylene used in Example 1, a linear low-density polyethylene (density: 0.930 g / cm ³ , melt index: 3.7 g / 10 minutes, particle size: 32 mesh pass) was used. ), The amount of polyolefin resin used from 30 parts
Changed to 20 parts and changed the amount of azodicarbonamide used to 10
A foam was obtained in the same manner as in Example 1 except that the number of parts was changed to 6 parts. The obtained foam had an overall thickness of 2.5 mm, an overall width of 1000 mm, and an apparent expansion ratio of 13 times.

The surface wetting tension of the obtained foam was measured according to JIS-K 67.
According to 68, it was 39 dyne / cm, which was extremely superior to the surface wetting tension of 31 dyne / cm of the foam made of only the linear low-density polyethylene. When the surface resistivity was examined in the same manner as in Example 1, it was extremely small, 2.3 × 10 ¹¹ Ω.

Next, when a printing ink or an adhesive was applied onto the surface of the obtained foam, no cissing phenomenon was observed and the adhesiveness with these was excellent.

Further, when metal vapor deposition was performed on the surface of the obtained foam, a very strong adhesive force was obtained.

From the above, it can be seen that the foamed product of the present invention is excellent not only in improving the adhesiveness by improving the surface wettability but also in the adhesiveness with the metal film.

Example 3 In Example 1, instead of the polyolefin resin and the linear low density polyethylene, the formula:

[0113]

[Chemical 29]

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

[0115]

[Chemical 30]

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

[0117]

[Chemical 31]

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

[0119]

[Chemical 32]

50 parts of a polyolefin resin having a weight average molecular weight of 43800 and having a linearly irregular arrangement of 9 mol% of a cationized maleimide structural unit represented by and 50 parts of low-density polyethylene were heated to 110 to 120 ° C. Melt with an extruder, blow a volatile solvent from the middle of the barrel of the extruder under pressure, knead until the foaming agent is uniformly dispersed in the resin, and adjust the temperature to a viscosity suitable for foaming. Then, it was extruded from the die under atmospheric pressure and expanded to obtain a foam. This foam has an overall thickness of 10 mm and an overall width of 60
The apparent expansion ratio was 0 × 10 mm.

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

(Half-life of electric charge) [0122] A voltage of 10 KV was applied to the sample in the same atmosphere as when the surface resistivity was measured, using a static Honest meter (manufactured by Shishido Shokai Co., Ltd.) to measure the applied electric charge. Determine the decay rate as the half-life.

(Bleed out) An additive-free biaxially oriented polypropylene film was laminated on the surface of the foam, and the temperature was 40 ° C. and 80% RH.
After putting it in the atmosphere for 7 days, it is taken out, the film is peeled from the foam, and the presence or absence of deposits on the surface of the film is examined.

(Blocking Shearing Force) Two foams were overlapped over a width of 3 cm and a length of 4 cm, a weight of 550 g was placed on the foam, and the foam was put in an atmosphere of 40 ° C. and 80% RH for 7 days, and then 2 times. The shear peeling force of the foam is measured by a Shopper type tensile tester.

A shear peeling force of 1000 g or less is regarded as acceptable. The amount is preferably 500 g or less.

Example 4 Formula:

[0127]

[Chemical 33]

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

[0129]

[Chemical 34]

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

[0131]

[Chemical 35]

20 parts of a polyolefin resin having a weight average molecular weight of 28400 linearly and irregularly arranged of 19 mol% of a cationized maleimide structural unit represented by and pulverized to have a 32 mesh path and 20 parts of azo as a foaming agent 8 parts of dicarbonamide straight chain low density polyethylene (density: 0.921 g / cm ³ , melt index: 3.2 g / 10 minutes,
Particle size: 32 mesh pass) 80 parts were added and mixed to obtain a foamable resin composition.

Using the foamable resin composition thus obtained, a crosslinked foamable sheet was prepared in the same manner as in Example 1, and then heated to obtain a foamed product. This foam has an overall thickness
It had a width of 2.5 mm, a total width of 1000 mm, and an apparent expansion ratio of 18 times.

The physical properties of the obtained foam were examined in the same manner as in Example 3. The results are shown in Table 1.

Example 5 In Example 4, as the polyolefin resin, the formula:

[0136]

[Chemical 36]

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

[0138]

[Chemical 37]

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

[0140]

[Chemical 38]

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

[0142]

[Chemical Formula 39]

20 parts of a linearly irregularly arranged weight average molecular weight polyolefin resin consisting of 18 mol% of a cationized maleimide structural unit represented by and the same linear low-density polyethylene 80 as used in Example 4 A foam was obtained in the same manner as in Example 4 except that parts were used. This foam had an overall thickness of 2.8 mm, an overall width of 1030 mm, and an apparent expansion ratio of 20 times.

The physical properties of the obtained foam were examined in the same manner as in Example 3. The results are shown in Table 1.

Example 6 Formula:

[0146]

[Chemical 40]

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

[0148]

[Chemical 41]

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

[0150]

[Chemical 42]

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

[0152]

[Chemical 43]

Polyolefin resin having a weight average molecular weight of 39800 linearly and irregularly composed of 8 mol% of a cationized maleimide structural unit represented by : 2.5g / 10 minutes, particle size: 32 mesh pass)
90 parts were added and mixed to obtain a foamable composition.

Then, a foam was obtained in the same manner as in Example 3 using the obtained foamable composition. The obtained foam is
The total thickness was 2.5 mm, the overall width was 450 mm, and the apparent expansion ratio was 9 times.

The physical properties of the obtained foam were examined in the same manner as in Example 3. The results are shown in Table 1.

Example 7 Instead of the polyolefin resin used in the polyolefin resin foam in Example 3, the polyolefin resin used in Example 1 and the polyolefin resin used in Example 2 were used in Example 3. Polyolefin resin 100 used
A foam was obtained in the same manner as in Example 3 except that a mixture of 50 parts per part was used. This foam has an overall thickness of 2.0 mm, an overall width of 950 mm and an apparent expansion ratio of 13
It was double.

The physical properties of the obtained foam were examined in the same manner as in Example 3. The results are shown in Table 1.

[0158]

[Table 1]

Comparative Example 1 99 parts of polypropylene (melt index: 2.5 g / 10 minutes, particle size: 32 mesh pass) and 1 part of stearic acid monoglyceride as an antistatic agent were mixed to obtain a foamable composition.

Next, a foam was obtained in the same manner as in Example 3 using the obtained foamable composition. The physical properties of the obtained foam were examined in the same manner as in Example 3. The results are shown in Table 2.

Comparative Example 2 99.2 parts of polypropylene (melt index: 2.5 g / 10 minutes, particles: 32 mesh pass) and the formula as an antistatic agent:

[0162]

[Chemical 44]

Betaine-type amphoteric surfactant represented by
8 parts were mixed to obtain a foamable composition. Next, a foam was obtained in the same manner as in Example 3 using the obtained foamable composition.

The physical properties of the obtained foam were examined in the same manner as in Example 3. The results are shown in Table 2.

Comparative Example 3 Linear low-density polyethylene (density: 0.921 g / cm ³ , melt index: 3.2 g / 10 minutes, particle size: 32 mesh pass) 98.5 parts, stearic acid monoglyceride and formula:

[0166]

[Chemical 45]

A betaine-type amphoteric surfactant represented by the formula (1: 1) was mixed at a weight ratio of 1.5 parts and 10 parts of azodicarbonamide as a foaming agent to obtain a foamable composition. A foam was obtained in the same manner as in Example 4 using the foamable composition obtained below.

The physical properties of the obtained foam were examined in the same manner as in Example 3. The results are shown in Table 2.

Comparative Example 4 95 parts of ethylene-propylene copolymer having an ethylene content of 5% by weight (melt index: 1.2 g / 10 minutes, particle size: 32 mesh pass), sodium dodecylbenzenesulfonate as an antistatic agent and polyethylene glycol In a weight ratio of 1: 1 5 parts, azodicarbonamide 10 parts as a blowing agent and dicumyl peroxide 2 as a cross-linking agent.
The parts were mixed to give a foamable composition. The obtained foamable composition is melted by an extruder heated to 160 to 170 ° C.,
The mixture was kneaded, placed in a heated mold in a predetermined amount, and sealed under pressure. Further, in this state, the foaming agent was decomposed by heating to a temperature at which the foaming agent decomposes, and then pressure was released to obtain a foam.

The physical properties of the obtained foam were examined in the same manner as in Example 3. The results are shown in Table 2.

Comparative Example 5 A foamable composition was obtained by mixing 99.2 parts of polypropylene (melt index: 2.5 g / 10 minutes, particle diameter: 32 mesh pass) and 1 part of stearyldiethanolamine as an antistatic agent.

Then, a foam was obtained in the same manner as in Example 3 using the obtained foamable composition.

The physical properties of the obtained foam were examined in the same manner as in Example 3. The results are shown in Table 2.

[0174]

[Table 2]

From the results shown in Table 1, the polyolefin resin foam of the present invention is excellent in that the surface resistivity which is an index of antistatic property is 1 × 10 ¹³ Ω or less and the charge half-life is 180 seconds or less. In addition, there is no bleed-out of the antistatic component from the foam, and therefore it is clear that the foam has excellent antistatic properties without blocking.

On the other hand, the foams obtained in Comparative Examples 1 to 5 were
The conventional comparatively low molecular weight surfactant type antistatic agent was used. From the results shown in Table 2, if the antistatic property is to be satisfied, the antistatic agent bleeds from the foam. It turns out that there is a drawback that blocking occurs because it is out.

From the above, the polyolefin resin foam of the present invention has excellent antistatic properties, and since there is no bleed-out of the antistatic agent and blocking does not occur, for example, the occurrence of damage due to static electricity must be prevented. It can be seen that it can be suitably used in the field where it is not required.

Examples 8 to 12 Foams were obtained in the same manner as in Examples 3 to 7 except that the blending ratio of the polyolefin resin and other polyolefin resin was changed as shown in Table 3. Using the obtained foam, the surface resistivity was examined as physical properties in the same manner as in Example 1, and the surface wetting tension, cissing and printability were examined according to the following methods. The results are shown in Table 3.

(Surface Wetting Tension) Measured according to JIS-K 6768.

(Hajiki) Printing ink for cellophane (CCS
T: Toyo Ink Mfg. Co., Ltd.) was applied with a # 50 bar coater, and after application, the ink application surface was observed by leaving it in the room
Judgment is made based on whether or not the ink film on the ink-coated surface is circular, and those having no ink are judged to be good, and those having a slight amount to ink are judged to be no.

(Printability) Printing ink for cellophane (CCS
T: Toyo Ink Mfg. Co., Ltd.) was applied with a # 50 bar coater, dried in a hot air dryer at 80 ° C to remove the solvent, and then cellophane adhesive tape was applied to the ink surface to quickly rotate 180 °
Peel off. The printability is evaluated by the remaining area of ink on the adhesive tape sticking part.

The evaluation criteria are as follows.

(Evaluation Criteria) Remaining area is less than 50% Index 1 Remaining area is 50% or more and less than 70% Index 2 Remaining area is 75% or more and less than 90% Index 3 Remaining area is 90% or more and less than 100% Index 4 Remaining area is 100% Index 5

[0184]

[Table 3]

Comparative Example 6 A foam was obtained in the same manner as in Comparative Example 1 except that the antistatic agent was not used.

The physical properties of the obtained foam were examined in the same manner as in Examples 8-12. The results are shown in Table 4.

Comparative Example 7 In Comparative Example 2, an ethylene-vinyl acetate copolymer (vinyl acetate content: 20% by weight, weight average molecular weight: 56000) was used in place of the antistatic agent, and an ethylene-vinyl acetate copolymer / A foam was obtained in the same manner as in Comparative Example 2 except that the weight ratio of polypropylene was adjusted to 15/85.

The physical properties of the obtained foam were examined in the same manner as in Examples 8-12. The results are shown in Table 4.

Comparative Example 8 In Comparative Example 3, an ethylene-ethyl acrylate copolymer (ethyl acrylate content:
18% by weight, weight average molecular weight: 50000)
A foam was obtained in the same manner as in Comparative Example 3 except that the weight ratio of ethyl acrylate copolymer / low density polyethylene was adjusted to 10/90.

The physical properties of the obtained foam were examined in the same manner as in Examples 8-12. The results are shown in Table 4.

Comparative Example 9 In Comparative Example 4, an ethylene-ethyl acrylate-maleic anhydride terpolymer was used in place of the antistatic agent (ethyl acrylate content: 14% by weight, maleic anhydride content:
2 wt%, weight average molecular weight: 58000), ethylene
-Ethyl acrylate- Maleic anhydride terpolymer /
A foam was obtained in the same manner as in Comparative Example 4 except that the weight ratio of the ethylene-propylene copolymer was adjusted to 20/80.

The physical properties of the obtained foam were examined in the same manner as in Examples 8-12. The results are shown in Table 4.

Comparative Example 10 In Comparative Example 5, an ethylene-methyl methacrylate-maleic anhydride terpolymer was used in place of the antistatic agent (methyl methacrylate content: 13% by weight, maleic anhydride content: 2% by weight, weight average). A foam was obtained in the same manner as in Comparative Example 5, except that the ethylene-methyl methacrylate-maleic anhydride terpolymer / polypropylene was adjusted to a weight ratio of 15/85 using a molecular weight of 61000).

The physical properties of the obtained foam were examined in the same manner as in Examples 8-12. The results are shown in Table 4.

[0195]

[Table 4]

As is clear from the results shown in Table 3, the polyolefin resin foams of the present invention obtained in Examples 8 to 12 have a clearly improved surface wettability and are subjected to a physical surface treatment. Without causing repelling of the coating agent, exhibiting good printability, adhesiveness and vapor deposition property, and further having an excellent antistatic property that the surface specific resistance, which is an index of antistatic property, is 1 × 10 ¹³ Ω or less. I understand.

On the other hand, as shown in Table 4, the foams according to the conventional methods obtained in Comparative Examples 6 to 10 would cause cissing and printability unless a coating agent of a specific component was used, unless corona discharge treatment was applied. It did not satisfy either the adhesiveness or the vapor deposition property, and naturally did not have a satisfactory antistatic property.

As described above, the foam having excellent surface wettability of the present invention can be subjected to processing such as printing, vapor deposition, laminating, etc. However, even if it is used alone, there is no obstacle due to static electricity. It can be preferably used in fields such as materials and packaging materials.

[0199]

EFFECT OF THE INVENTION The polyolefin resin foam of the present invention has an excellent antistatic property without bleed-out, and therefore has no dust adhesion and does not give a shock to the human body due to electrostatic discharge. It is a foam with excellent handling properties.

Further, the polyolefin resin foam of the present invention exhibits extremely excellent surface wettability, adhesiveness,
It is a foam with excellent repellency, printability and vapor deposition of the coating.

Claims (1)

[Claims] 1. General formula (I): (In the formula, 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 (I
I): [Chemical 2] (In the formula, R ² represents an alkyl group having 1 to 4 carbon atoms) 0 to 15 mol% of an acrylate structural unit represented by the general formula (I
II): [Chemical Formula 3] (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 and the general formula (IV): (In the formula, R ⁴ is an alkylene group having 2 to 8 carbon atoms, R ⁵ and R ⁶ are respectively 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. Arylalkyl group, 2 to 2 carbon atoms which may be substituted with an alkyl group
An epoxy group having 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 ) and a polyolefin resin having a weight average molecular weight of 1000 to 50000 linearly and irregularly arranged of 1 to 35 mol% of a cationized maleimide structural unit, and a general formula (I): (Wherein R ¹ is the same as above) 45 to 98.5 mol% of an olefin structural unit represented by the general formula (II): (Wherein R ² is the same as above) 0 to 15 mol% of an acrylate structural unit represented by the general formula (V): (In the formula, R ¹ and R ³ are the same as above, m is 0 or 1
Is represented by) and an alkylmaleimide structural unit represented by 0.5
~ 5 mol% and general formula (VI): (Wherein R ¹ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , X and m are the same as described above), and the cationized maleimide structural units represented by 1 to 35 mol% are linearly and irregularly arranged. A polyolefin resin foam comprising at least one polyolefin resin having a weight average molecular weight of 1,000 to 50,000.