JPH09118769A - Polyolefin resin foam and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyolefin resin foam having excellent elasticity and cushioning properties because of its low density, and having good surface properties and a high rate of closed cells and to provide a process for producing the foam. SOLUTION: This polyolefin resin foam prepared by extrusion-foaming a polyolefin resin composition containing a polyolefin resin, a polycarbonate resin and a compatibilizer is provided. A polyolefin resin composition containing a polyolefin resin, a polycarbonate resin and a compatibilizer is melted by heating, and the melt is impregnated with a vaporizable blowing agent. The temperature of the composition is adjusted to a temperature suitable for foaming, and it is extrusion-foamed into a low-pressure zone.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyolefin resin foam and a method for producing the same. More specifically, it relates to a polyolefin resin foam that can be suitably used as a structural material such as a wall of a building, a partition or the like, a cushioning material for a high-load precision instrument packaging, and a method for producing the same.

[0002]

2. Description of the Related Art Polyolefin is inexpensive and excellent in various physical properties, and is therefore widely used in various fields.

When the polyolefin is used as a foaming material, the viscosity of the polyolefin decreases sharply when it is melted. This is an important point in manufacturing.

Generally, in the polyolefin bead foaming method, the temperature of the crystalline polyolefin is maintained in a semi-molten state by delicate temperature control, the proper viscosity for foaming is maintained, and the heat of vaporization of the volatile foaming agent is maintained. The pre-expanded particles having a high closed cell ratio are produced by utilizing the cooling effect of

On the other hand, in the extrusion foaming method of polyolefin, it is not possible to perform extrusion foaming in a state where the crystal of the crystalline polyolefin is semi-molten, and it is necessary to make it into a completely molten state. Cannot maintain a proper viscosity. If the crystalline polyolefin is extruded and foamed in a completely molten state, the bubbles will be broken in the process of foaming and growth, and the shrinkage will be large, so that a foam having beautiful closed cells cannot be produced.

Therefore, the combined use of polyolefin and polycarbonate has been studied (JP-A-57-1).
No. 6033 gazette and Japanese Patent Publication No. 58-29729 gazette), although it can be said that a certain degree of improvement in the closed cell ratio is observed when both are used in combination, the closed cell ratio is still insufficient, and It cannot be said that the surface properties of the molded product are good.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and because of the low foam density, it has excellent elasticity and cushioning properties, good surface properties, and is independent. An object of the present invention is to provide a polyolefin resin foam having a high cell rate and a method for producing the same.

[0008]

The present invention is directed to a polyolefin resin foam obtained by extruding and foaming a polyolefin resin composition containing a polyolefin resin, a polycarbonate resin and a compatibilizer, and a polyolefin resin and a polycarbonate. A polyolefin resin composition containing a resin and a compatibilizer is heated and melted, impregnated with an evaporative foaming agent, and the temperature of the polyolefin resin composition is adjusted to a temperature suitable for foaming, and then extruded into a low pressure region. The present invention relates to a method for producing a polyolefin resin foam, which is characterized by foaming.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the polyolefin resin foam of the present invention is obtained by extrusion-foaming a polyolefin resin composition containing a polyolefin resin, a polycarbonate resin and a compatibilizer. Is.

Typical examples of the polyolefin resin include polypropylene resin and polyethylene resin.

The polypropylene resin may be a propylene homopolymer, a block copolymer or a random copolymer. Among these, polypropylene-based copolymers and propylene homopolymers containing 75% by weight or more of propylene are particularly preferable.
As the copolymerizable monomer in the polypropylene-based copolymer, for example, ethylene, 1-butene, isobutene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3 , 4-dimethyl-
1-butene, 1-heptene, 3-methyl-1-hexene, 1-octene, 1-decene and other α-olefins having 2 or 4 to 12 carbon atoms, cyclopentene, cyclic olefins such as norbornene, and 5-methylene- 2-norbornene, 5-ethylidene-2-norbornene, 1,4-
Dienes such as hexadiene, methyl-1,4-hexadiene, 7-methyl-1,6-octadiene and the like can be mentioned.

The polyethylene resin may be an ethylene homopolymer, a block copolymer or a random copolymer. Among these, polyethylene-based copolymers containing 75% by weight or more of ethylene and ethylene homopolymers are particularly preferable. Examples of the copolymerizable monomer in the polyethylene-based copolymer include propylene, 1-butene, isobutene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, and 3 , 4-dimethyl-1-butene,
1-heptene, 3-methyl-1-hexene, 1-octene, 1-decene and the like having 2 or 4-12 carbon atoms α-
Olefins, cyclopentene, cyclic olefins such as norbornene, 5-methylene-2-norbornene, 5-ethylidene-2-norbornene, 1,4-hexadiene,
Methyl-1,4-hexadiene, 7-methyl-1,6-
Examples include octaene and other dienes.

The melt flow index (MI) of the polyolefin resin is in accordance with ASTM D 1238, the polypropylene resin is 230 ° C., and the polyethylene resin is 190 ° C. under a load of 2.16 kg. From the viewpoint that the workability of the polyolefin resin composition containing a resin is improved, 0.2
It is preferably 20 or less, more preferably 10 or less, from the viewpoint that the foamability is improved by maintaining the viscosity of the polyolefin-based resin composition during melting to an extent suitable for foaming. .

In the present invention, other resins and rubbers may be added to the polyolefin resin as long as the object of the present invention is not impaired.

Typical examples of the polycarbonate resin include bis (4-hydroxyphenyl) methane, 2,2-bis (4'-hydroxyphenyl) propane (bisphenol A), and 2,2-bis (3 ', 5'-
Dibromo-4'-hydroxyphenyl) propane, 2,
Bis- (hydroxyaryl) alkane represented by 2-bis (3 ', 5'-dichloro-4'-hydroxyphenyl) propane and the like; bis (hydroxyaryl) ether, bis (hydroxyaryl) sulfoxide, bis (hydroxyaryl) ) Sulfonic acid, phosgene,
A polymer obtained by reacting a polycarbonate precursor represented by diphenyl carbonate or the like by a known technique can be used. Also, from bisphenol A and 2,2-bis (3 ', 5'-dibromo-4'-hydroxyphenyl) propane or 2,2-bis (3', 5'-dichloro-4'-hydroxyphenyl) propane A copolymer obtained by a known method can also be used.
Among these, aromatic polycarbonate obtained from bisphenol A alone or bisphenols containing 70% by weight or more of bisphenol A is particularly preferable.

The weight average molecular weight of the polycarbonate resin is not particularly limited, but is usually 5,000 to 100.
000 is preferred.

The compatibilizer may be used without particular limitation as long as it enhances the compatibility between the polyolefin resin and the polycarbonate resin.

Typical examples of the compatibilizer include an epoxy group-containing polyolefin resin, a polyolefin resin modified with an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative, and the like, which may be used alone or in combination.
A mixture of more than one species is used.

When the compatibilizing agent is an epoxy group-containing polyolefin resin, the epoxy group content of the epoxy group-containing polyolefin resin is such that compatibility with the polycarbonate resin is sufficiently exhibited. From the point of view, it is preferably 0.05% by weight or more, more preferably 0.2% by weight or more, and the effect of improving the foamability and processability by the combined use of the polyolefin resin and the polycarbonate resin is sufficiently exhibited. From the viewpoint, it is preferably 50% by weight or less, especially 30% by weight or less.

Typical examples of the epoxy group-containing polyolefin resin include copolymers of glycidyl methacrylate, glycidyl acrylate, α-methyl glycidyl acrylate, α-methyl glycidyl methacrylate, vinyl glycidyl ether, methacryl glycidyl ether and polyolefin. Alternatively, a graft polymer may be used.

When the compatibilizing agent is a polyolefin resin modified with an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative, the unsaturated carboxylic acid or unsaturated carboxylic acid ester contained in the modified polyolefin resin is used. The content of the group based on 0.01 is 0.01 from the viewpoint that compatibility with the polycarbonate resin is sufficiently exhibited.
The content is preferably not less than 0.2% by weight, more preferably not less than 0.2% by weight, and 50% by weight from the viewpoint that the effect of improving the foamability and processability by the combined use of the polyolefin resin and the polycarbonate resin is sufficiently exhibited. Hereafter, it is preferably 30% by weight or less.

Typical examples of the polyolefin resin modified with the unsaturated carboxylic acid or the unsaturated carboxylic acid derivative are, for example, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid and the like. Examples thereof include copolymers and graft polymers.

The ratio of the polyolefin resin to the polycarbonate resin (polyolefin resin / polycarbonate resin: weight ratio) is 55/45 or more from the viewpoint of uniformly dispersing the polycarbonate resin in the polyolefin resin, It is preferably 70/30 or more, more preferably 95/5 or less and 90/90 or more from the viewpoint of improving foamability and processability.
It is preferably 10 or less.

The amount of the compatibilizing agent is not particularly limited as long as it can enhance the compatibility between the polyolefin resin and the polycarbonate resin, but the viewpoint of improving the foamability and processability. Therefore, the total of polyolefin resin and polycarbonate resin is 100
It is preferably 1 part by weight or more, especially 5 parts by weight or more with respect to parts by weight, and 40 parts by weight or less, particularly 3 parts by weight from the viewpoint of eliminating the possibility of deterioration in processability.
It is preferably 0 parts by weight or less.

The polyolefin-based resin composition containing the above-mentioned polyolefin-based resin, polycarbonate-based resin and compatibilizer may include, if necessary, a cell nucleating agent (nucleating agent), an ultraviolet absorber and an antioxidant. Additives such as lubricants, antistatic agents, etc. may be added within a range that does not impair the object of the present invention.

The bubble nucleating agent may be one that is commonly used. Specific examples of the cell nucleating agent include inorganic powders such as talc and silica; organic fine powders such as zinc stearate and calcium stearate;
Examples include fine powders that generate gas by heating a mixture of citric acid and sodium hydrogen carbonate.

In the present invention, the order and method of mixing the polyolefin resin, the polycarbonate resin, the compatibilizer, and the additives added as necessary are not particularly limited.

The method for producing the polyolefin resin foam of the present invention will be described below.

According to the method for producing a polyolefin resin foam of the present invention, as described above, a polyolefin resin composition containing a polyolefin resin, a polycarbonate resin and a compatibilizer is heated and melted to form an evaporation type foam. A polyolefin-based resin foam is obtained by impregnating the agent, adjusting the temperature of the polyolefin-based resin composition to a temperature suitable for foaming, and then extruding and foaming in a low-pressure region.

First, in the present invention, a polyolefin resin, a polycarbonate resin and a compatibilizing agent, and if necessary, additives such as a stabilizer, a lubricant and a cell nucleating agent are melted in the polyolefin resin and the polycarbonate resin. Kneading is carried out in a kneading machine usually used in this state.

Examples of the kneader include rolls, co-kneaders, Banbury mixers, Brabenders, single-screw extruders, twin-screw extruders, and other kneaders and extruders.
Among these, an extruder is preferable from the viewpoint of productivity,
In particular, a twin-screw extruder having a large shear force for kneading the polymers is more preferable.

There is no particular limitation on the method of mixing the polyolefin resin, the polycarbonate resin, the compatibilizer, and the additives as necessary. As an example, there may be mentioned a method in which the polyolefin-based resin composition is heated to 170 to 250 ° C., melt-kneaded with a twin-screw extruder, and then produced into a pellet if necessary.

As a method of impregnating a heat-melted polyolefin resin composition with an evaporative foaming agent and performing extrusion foaming, for example, a polyolefin resin composition is prepared by a kneading machine which is usually used, and then the resin composition is prepared. A material by impregnating an evaporative foaming agent, and then discharging it outside the kneading machine to foam, a method of extruding and foaming after impregnating the evaporative foaming agent into a polyolefin-based resin composition in the kneading machine, a polyolefin-based material Examples include a method of using a kneading device capable of simultaneously performing the step of kneading a resin composition and the step of impregnating an effervescent foaming agent and foaming, and extruding and foaming outside the kneading apparatus after kneading.

Typical examples of the evaporative blowing agent include aliphatic hydrocarbons such as n-propane, n-butane, isobutane, n-pentane, isopentane, neopentane, n-hexane, isohexane and heptane; cyclobutane, Alicyclic hydrocarbons such as cyclopentane and cyclohexane; chlorodifluoromethane, difluoromethane, trifluoromethane, trichlorofluoromethane,
Dichlorofluoromethane, dichlorodifluoromethane,
Halogenated hydrocarbons such as chloromethane, dichloromethane, chloroethane, dichlorotrifluoroethane, tetrafluoroethane, difluoroethane, pentafluoroethane, trifluoroethane, trichlorotrifluoroethane, dichlorotetrafluoroethane, chloropentafluoroethane, perfluorocyclobutane Examples thereof include inorganic gases such as carbon dioxide, nitrogen and air; water and the like, and these foaming agents can be used alone or in combination of two or more kinds.

The amount of the evaporative foaming agent used is not particularly limited and may be appropriately adjusted according to the desired expansion ratio of the foamed product obtained. Usually, the amount of the evaporative foaming agent used is about 5 to 50 parts by weight based on 100 parts by weight of the total amount of the polyolefin resin, the polycarbonate resin and the compatibilizer.

As a method for extruding and foaming the heat-melted polyolefin-based resin composition, for example, a single-screw extruder, a tandem-type extruder having two kneading regions, or the like is used to preliminarily add the evaporation-type foaming agent to the resin composition. Examples of the method include foaming by impregnating the same with or by impregnating it in an extruder and extruding from a die.

When the polyolefin resin composition is extruded and foamed, the temperature of the resin composition is adjusted to a temperature suitable for foaming (hereinafter referred to as a proper foaming temperature) and then extruded and foamed in a low pressure region.

The proper foaming temperature may be appropriately adjusted according to the composition of the polyolefin resin composition. Generally, for example, when a tandem type extruder is used, the temperature of the first-stage kneading section is raised to 200 to 300 ° C., the evaporative foaming agent is injected and impregnated in the second-stage kneading section, and an appropriate foaming temperature, for example, 150 to 2 is obtained.
It can be foamed by extruding from a die at about 50 ° C.

The low pressure region is usually under atmospheric pressure,
If necessary, the atmosphere may be depressurized to be lower than atmospheric pressure.

The polyolefin resin foam of the present invention thus obtained is lightweight, has a beautiful surface, and has a high closed cell ratio, and therefore, for example, as a packaging material, a cushioning material, a heat insulating material, etc. It can be preferably used.

[0041]

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

Example 1 A resin composition comprising 75 parts by weight of polypropylene, 25 parts by weight of polycarbonate and 10 parts by weight of polypropylene grafted with 0.5% by weight of glycidyl methacrylate was used as a twin-screw extruder having a diameter of 32 mm (L / D = 25.5)
, The temperature of 260 ℃, screw rotation speed 100 rp
The resin composition was melt-kneaded at m to form pellets.

Using 100 parts by weight of the obtained pellets, 0.05 part by weight of blended oil and 0.1 part by weight of sodium bicarbonate-citric acid as a foam nucleating agent were mixed in a ribbon blender.

The mixed pellets were fed to a 40 mm-50 mmφ tandem type extruder, and the first stage extruder (40 mmφ) was used.
After being melted in the medium at 250 ° C., isorich butane (n-butane / i-butane (weight ratio) = 15 as a foaming agent
/ 85) was mixed by press-fitting 10 parts by weight with respect to 100 parts by weight of the mixed resin, and the resin temperature was adjusted to 16 by a second stage extruder (50 mmφ).
It was cooled to 0 ° C. and discharged from a cylindrical die (6 mmφ × 25 mm) into atmospheric pressure to obtain a round rod-shaped foam.

As the physical properties of the obtained foam, (a) foam density, (b) surface property, and (c) closed cell ratio were examined according to the following methods. Table 1 shows the results.

(A) Foam density Measured according to JIS-K 6767.

(B) Surface property The surface of the foam was visually observed and evaluated based on the following evaluation criteria.

(Evaluation Criteria) A: Surface shrinkage and wrinkle are less than 5% of the whole. B: Surface shrinkage and wrinkle are 5% or more and less than 15% of the whole. C: Surface shrinkage and wrinkles are 15% or more and less than 30% with respect to the whole. D: Surface shrinkage and wrinkle are 30% or more based on the whole.

(C) Closed cell ratio According to the method described in ASTM D-2856, air pycnometer (manufactured by Beckman, MOD)
Measured using EL 930).

Example 2 A resin composition comprising 70 parts by weight of polypropylene, 30 parts by weight of polycarbonate and 10 parts by weight of polypropylene grafted with 0.5% by weight of maleic anhydride was used to prepare a twin-screw extruder (L / D) having a diameter of 32 mm. = 25.5),
The resin composition was melt-kneaded at a temperature of 260 ° C. and a screw rotation speed of 100 rpm to form pellets.

Using 100 parts by weight of the obtained pellets, 0.05 part by weight of blended oil and 0.1 part by weight of sodium bicarbonate-citric acid as a foaming nucleating agent were mixed in a ribbon blender.

The mixed pellets were fed to a 40 mm-50 mmφ tandem type extruder, and the first stage extruder (40 mmφ) was used.
After being melted in the medium at 250 ° C., isorich butane (n-butane / i-butane (weight ratio) = 15 as a foaming agent
/ 85) was mixed by press-fitting 10 parts by weight with respect to 100 parts by weight of the mixed resin, and the resin temperature was adjusted to 16 by a second stage extruder (50 mmφ).
It was cooled to 0 ° C. and discharged from a cylindrical die (6 mmφ × 25 mm) into atmospheric pressure to obtain a round rod-shaped foam.

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

Example 3 75 parts by weight of low density polyethylene, 25 polycarbonate
A resin composition comprising 10 parts by weight and 10 parts by weight of ethylene-glycidyl methacrylic acid copolymer (Sumitomo Chemical Co., Ltd., Bondfast E, glycidyl methacrylate content: 12% by weight) is used as a twin screw extruder having a diameter of 32 mm ( L /
D = 25.5), and the resin composition was melt-kneaded at a temperature of 240 ° C. and a screw rotation speed of 100 rpm to form pellets.

Using 100 parts by weight of the obtained pellets, 0.05 part by weight of blended oil and 0.1 part by weight of sodium bicarbonate-citric acid as a foam nucleating agent were mixed with a ribbon blender.

The mixed pellets were supplied to a 40 mm-50 mmφ tandem type extruder, and the first stage extruder (40 mmφ) was used.
After melting at 240 ° C. in the medium, isorich butane (n-butane / i-butane (weight ratio) = 15 as a foaming agent
/ 85) was mixed by press-fitting 10 parts by weight with respect to 100 parts by weight of the mixed resin, and the resin temperature was adjusted to 16 by a second stage extruder (50 mmφ).
It was cooled to 0 ° C. and discharged from a cylindrical die (6 mmφ × 25 mm) into atmospheric pressure to obtain a round rod-shaped foam.

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

Comparative Example 1 90 parts by weight of polypropylene and 10 of polycarbonate
The resin composition consisting of parts by weight was supplied to a twin-screw extruder (L / D = 25.5) having a diameter of 32 mm, and the resin composition was melt-kneaded at a temperature of 260 ° C. and a screw rotation speed of 100 rpm to form pellets. .

Using 100 parts by weight of the obtained pellets, 0.05 part by weight of blended oil and 0.1 part by weight of baking soda-citric acid as a foam nucleating agent were mixed in a ribbon blender.

The mixed pellets were supplied to a 40 mm-50 mmφ tandem type extruder, and the first stage extruder (40 mmφ) was used.
After being melted in the medium at 250 ° C., isorich butane (n-butane / i-butane (weight ratio) = 15 as a foaming agent
/ 85) was mixed by press-fitting 10 parts by weight with respect to 100 parts by weight of the mixed resin, and the resin temperature was adjusted to 16 by a second stage extruder (50 mmφ).
It was cooled to 0 ° C. and discharged from a cylindrical die (6 mmφ × 25 mm) into atmospheric pressure to obtain a round rod-shaped foam.

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

Comparative Example 2 Using 100 parts by weight of polypropylene, 0.05 part by weight of blended oil and 0.1 part by weight of baking soda-citric acid as a foam nucleating agent were mixed in a ribbon blender.

The mixture was supplied to a 40 mm-50 mmφ tandem type extruder and melted at 230 ° C. in a first stage extruder (40 mmφ), and then isorich butane (n-butane / i-butane) was used as a foaming agent. (Weight ratio) = 15/8
5) was mixed by press-fitting 10 parts by weight to 100 parts by weight of the resin component, cooled to a resin temperature of 150 ° C. by a second stage extruder (50 mmφ), and discharged from a cylindrical die (6 mmφ × 25 mm) to atmospheric pressure. To obtain a round bar-shaped foam.

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

Comparative Example 3 Polypropylene 10 grafted with 100 parts by weight of polypropylene and 0.5% by weight of glycidyl methacrylate.
The resin composition consisting of 1 part by weight is supplied to a twin-screw extruder having a diameter of 32 mm (L / D = 25.5), and the resin composition is melt-kneaded at a temperature of 260 ° C. and a screw rotation speed of 100 rpm to form pellets. did.

Using 100 parts by weight of the obtained pellets, 0.05 part by weight of blended oil and 0.1 part by weight of baking soda-citric acid as a foam nucleating agent were mixed in a ribbon blender.

The mixed pellets were fed to a 40 mm-50 mmφ tandem type extruder, and the first stage extruder (40 mmφ) was used.
After being melted in the medium at 250 ° C., isorich butane (n-butane / i-butane (weight ratio) = 15 as a foaming agent
/ 85) was mixed by press-fitting 10 parts by weight with respect to 100 parts by weight of the mixed resin, and the resin temperature was adjusted to 15 at a second stage extruder (50 mmφ).
It was cooled to 0 ° C. and discharged from a cylindrical die (6 mmφ × 25 mm) into atmospheric pressure to obtain a round rod-shaped foam.

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

Comparative Example 4 100 parts by weight of polypropylene and 0.
A resin composition consisting of 10 parts by weight of polypropylene grafted with 5% by weight was used for a twin-screw extruder (L /
D = 25.5), and the resin composition was melt-kneaded at a temperature of 260 ° C. and a screw rotation speed of 100 rpm to form pellets.

Using 100 parts by weight of the obtained pellets, 0.05 part by weight of blended oil and 0.1 part by weight of baking soda-citric acid as a foam nucleating agent were mixed in a ribbon blender.

The mixed pellets were supplied to a 40 mm-50 mmφ tandem type extruder, and the first stage extruder (40 mmφ) was used.
After melting at 230 ° C. in the medium, isorich butane (n-butane / i-butane (weight ratio) = 15 as a foaming agent
/ 85) was mixed by press-fitting 10 parts by weight with respect to 100 parts by weight of the mixed resin, and the resin temperature was adjusted to 15 at a second stage extruder (50 mmφ).
It was cooled to 0 ° C. and discharged from a cylindrical die (6 mmφ × 25 mm) into atmospheric pressure to obtain a round rod-shaped foam.

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

The resin used in each Example and each Comparative Example was polypropylene (Sumitomo Noblen D501 manufactured by Sumitomo Chemical Co., Ltd., melt flow index: 0.5 (2
(Measured at 30 ° C.)), low density polyethylene (G201 manufactured by Sumitomo Chemical Co., Ltd., melt flow index: 2 (1
(Measured at 90 ° C.)), polycarbonate (Taflon A2700 manufactured by Idemitsu Petrochemical Co., Ltd., weight average molecular weight: 270)
00).

[0074]

[Table 1]

From the results shown in Table 1, the foams obtained in Examples 1 to 3 had a low foam density and a low surface density due to the combined use of the polycarbonate resin and the compatibilizer. It can be seen that it has excellent properties and has a high closed cell rate.

[0076]

The present invention provides a polyolefin resin foam having a low foam density, excellent elasticity and cushioning properties, good surface properties, and a high closed cell rate.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B29K 105: 04

Claims (4)

[Claims] 1. A polyolefin resin foam obtained by extruding and foaming a polyolefin resin composition containing a polyolefin resin, a polycarbonate resin, and a compatibilizer. 2. The polyolefin resin foam according to claim 1, wherein the compatibilizing agent is an epoxy group-containing polyolefin resin or a polyolefin resin modified with an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative. 3. A polyolefin-based resin composition containing a polyolefin-based resin, a polycarbonate-based resin and a compatibilizing agent is heated and melted and impregnated with an evaporation type foaming agent,
A method for producing a polyolefin-based resin foam, which comprises adjusting the temperature of the polyolefin-based resin composition to a temperature suitable for foaming and then extruding and foaming in a low-pressure region. 4. The method for producing a polyolefin resin foam according to claim 3, wherein the compatibilizing agent is an epoxy group-containing polyolefin resin or a polyolefin resin modified with an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative.