JPS63312332A - Polyolefin polymer foam - Google Patents

Abstract

PURPOSE:To obtain the titled foam giving a stable product having remarkably improved heat-deformation ratio and high accuracy, by compounding chopped polyester fiber or polymer to a base polymer. CONSTITUTION:A crosslinked polyolefin polymer foam is compounded with >=1wt.% of chopped polyester fiber and/or polyester polymer. Preferably, the fiber has a diameter of <=2mm and fiber length of <=5mm and the polymer has particle size passing through 20-200 mesh sieve.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a polyolefin resin foam.

More specifically, the present invention relates to a polyolefin resin foam with significantly improved thermal deformation rate.

[Conventional technology]

Polyolefin resin foams are widely used for vehicle interior materials, insulation panels, etc. For example, they are used as interior materials for vehicles such as automobiles, such as door linings, ceilings, and instrument panels. On the other hand, examples of heat insulating materials include fillers for the outer walls of refrigerators, fillers for the inner walls of buildings, and pipe lining materials for water, waste, steam, etc.

[Problem that the invention seeks to solve]

In these applications, polyolefin resin foams are closed cells, so by appropriately selecting the expansion ratio, it is possible to obtain moderate elasticity and excellent heat insulation, and it has excellent properties such as low density and lightness. However, it has the disadvantage of a large thermal deformation rate at high temperatures.

Therefore, when thermoforming is carried out, there is a drawback that molding workability at high temperatures is difficult and it is difficult to obtain molded products with high precision.

[Means for solving problems]

In order to achieve the above object, the present invention consists of the following configuration.

That is, it is a polyolefin resin foam characterized in that the crosslinked polyolefin resin foam contains at least 1% by weight of cut polyester fibers and/or polyester resin.

The present invention will be explained in more detail.

The polyolefin resins used in the present invention include not only low-, medium-, and high-density polyethylene resins, but also copolymerized polyethylene resins in which α-olefin is copolymerized with these polyethylene resins, polypropylene resins, and ethylene and/or butene resins containing 0.5 to 0.5 to Examples include 35% random, block, and random-block copolymerized polypropylene resins. Furthermore, a resin composition formed by mixing a copolymer resin mainly composed of ethylene or a petroleum resin which is compatible with these resins may be used.

The polyolefin resin foam used in the present invention is preferably a crosslinked type. Therefore, an appropriate amount of divinylbenzene, diallyl phthalate, etc. can be added as a crosslinking accelerator. In addition, pigments for coloring, inorganic fillers, heat stabilizers,
Additives such as ultraviolet absorbers, antioxidants, and nucleating agents can be added.

Examples of the polyester fiber used in the present invention include polyester fibers made of polyethylene terephthalate mixed with polyethylene isophthalate or polybutylene terephthalate. Of course, copolymerized polyester fibers can also be used.

These fibers preferably have a diameter of 2 mm or less and a fiber length of 5 mm or less. Although the cross-sectional shape of the fibers does not matter, it is preferable to remove auxiliary agents such as processing agents and oils adhering to the ls fibers.

The polyester resin used in the present invention is made of the same polymer as fibers, and is preferably in the form of flakes that can be passed through a 20 to 200 mesh sieve by cutting or crushing a sheet-like material containing a film.

In the present invention, the content of polyester fiber and/or polyester resin needs to be at least 1% by weight. If the content is less than this, the effect of improving the thermal deformation rate will be small. On the other hand, the upper limit of the content is not particularly limited, and the content is preferably 30% by weight or less. If the content is too high, it will be difficult to handle gas during foaming.

Because the jqed foam has flakes of polyester fibers and polyester film dispersed inside it,
These substances form a skeleton and prevent the foam from being thermally deformed when the foam is heated and molded, so that a product with a stable shape can be obtained.

The polyolefin resin foam according to the present invention is used for the following purposes.

First, batt materials for molded interiors of vehicles such as automobiles are mentioned. Usually, molded interior parts for vehicles are formed into a laminate in which a skin material is bonded to one side of a foam, which is further bonded to a base material to form a molded interior part. The skin materials include polyolefin resin sheets, polyvinyl chloride resin sheets, knitted fabrics using fibers,
Examples include fabrics such as nonwoven fabrics. On the other hand, AB as a base material
Examples include S resin sheets or molded products, polyolefin resin sheets or molded products, and molded products such as hardboard.

The method for crosslinking the polyolefin resin foam according to the present invention includes a method using ionizable eA radiation and a chemical crosslinking method using a chemical crosslinking agent such as dicumyl peroxide, and these methods can be used alone or in combination.

Furthermore, known foaming agents and foaming methods can be used.

The polyolefin resin foam according to the present invention can be manufactured as follows.

First, a polyolefin resin (unnecessary if crosslinking agents, blowing agents, and other additives have been added in advance) is mixed with the above-mentioned chemicals and flakes of polyester fiber or film and fed to the extruder. It can be obtained by making a sheet-like product by crosslinking and foaming. Then, the above-described laminate and base material are formed into an interior molded product by means of heat pressure molding or heat vacuum molding.

In the interior molded product using the polyolefin resin foam according to the present invention, aggregates in the form of flakes of polyester fibers and polyester films are dispersed and embedded in the foam, so these aggregates By suppressing thermal deformation, a molded product with a stable shape can be obtained without the occurrence of gaps due to thermal deformation at the joints between the respective members of the molded product.

Next, the polyolefin resin foam according to the present invention is a closed cell, has excellent heat insulating effect, and is used as a heat insulating material. Examples include refrigerants, lining materials for hot water insulation, and filling materials for refrigerator walls and doors.

In particular, lining materials for pipes, tanks, etc. are thermoformed to suit their shape, but as shown in the previous example, their thermal deformation rate is low, so they can be easily peeled off by thermoforming with sheets or base materials made of other resins. It has the excellent feature of not

〔Example〕

80% polypropylene resin with 4% ethylene copolymerized
100 parts by weight of a 20% polyethylene resin mixture with a density of 0.930 C]/cm3 and a melt index of 7.0, 15 parts by weight of a pyrolytic blowing agent, and 5 parts by weight of diallyl phthalate as a crosslinking accelerator. A composition obtained by uniformly mixing 1, 5, or 10 parts by weight of finely chopped polyethylene terephthalate polyester fibers (100 denier, length 1 mm) with respect to the resin was added to the mixture to a thickness of 2 mm. After forming the resin into a sheet, the resin was heated to a temperature above the decomposition temperature of the foaming agent to form a cross-linked bond and foamed.

This foam is bonded to a polypropylene resin sheet using an adhesive method, and then the composite material is heated and vacuum formed (with a mold diameter of 5 mm).
0mm, depth 30mm>, and finish condition at the deepest corner (peeling, shrinkage, edge finish)
Good results were obtained.

On the other hand, for comparison, a foam without polyester fiber mixed therein was molded in the same manner as in the example. As a result, the foam contracted after molding and a peeling state was observed at a part of the adhesive interface.

The results are shown in Table 1.

In addition, the gel fraction and adhesive releasability were evaluated as follows.

(Gel fraction) The foam was cut into fine pieces, weighed to a precision of 0.10, placed in a 10○ mesh wire mesh bag, and extracted with hot tetralin at 130°C. The percentage of remaining amount was expressed as gel fraction.

(adhesive releasability) ○: Foam remains on the base material side.

△: A state in which no foam remained partially on the base material side.

〔Effect of the invention〕

By having the above-described structure, the present invention achieves the following excellent effects.

(1) Polyester fibers or film flakes with a higher Tm (DSC> than the resin) are dispersed and buried in the polyolefin resin that becomes the foam to form an aggregate. As a result of suppressing the thermal deformation rate of the polyester resin foam, even when using the heat molding method, there are no gaps between the components forming the composite material and no peeling, making it possible to obtain stable products. can significantly improve the quality and yield of

(2) Since the polyolefin resin foam according to the present invention is melt-molded after mixing the above-mentioned polyester fibers and film flakes into the resin, it does not require special equipment and can be easily used with existing equipment. can be manufactured.

Claims (1)

[Claims] (1) A polyolefin resin foam characterized in that the crosslinked polyolefin resin foam contains at least 1% by weight of cut polyester fibers and/or polyester resin.