JP2001047539A - Multilayer polystyrene resin foam molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer polystyrene resin foam molded body for which a sophisticated process for injecting a foamed body after a semi-molded product is manufactured is not required, and in which the outer appearance of the foam molded body thus manufactured is beautiful and lightweight properties, mechanical strength, heat insulation properties, cushioning properties, vibration isolation properties, oil resistance, impact resistance and the like are provided. SOLUTION: In the constitution of a multilayer polystyrene resin foam molded body, a multilayer parison 6 having a mixed resin layer 3 on the outer face of a polystyrene resin foamed layer 2 is so molded in a mold as to fusion bond together with at least a part of respective inner faces of the parison, and the mixed resin layer is composed of a mixture of 20-80 wt.% polystyrene resin (1) and 20-80 wt.% polyolefin resin or polyester resin (2) (The total of (1) and (2) is 100 wt.%).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer polystyrene resin foam molded article used for lightweight heat insulating panels such as floors and doors, pallets, containers, automobile members and the like.

[0002]

2. Description of the Related Art Hitherto, multi-layer resin foam molded articles of various shapes in which a thermoplastic resin layer is laminated on the surface of a resin foam layer have been known. As a molded body of this type, for example, a molded body having a hollow structure is formed of a thermoplastic resin, and a cavity inside the molded body is filled with a method of injecting a urethane resin or a method of filling and molding resin foam particles. There are molded foams (JP-B-58-10217, JP-A-6-339979, etc.). However, these methods have a problem that the molding process is complicated because the molding of the resin layer on the surface and the formation of the foam layer inside are separate steps,
There is a problem that a special molding machine is required, and as a result, foamed molded articles formed by these methods are expensive.

A multilayer resin foam molded article obtained by molding a hollow multilayer parison having a thermoplastic resin layer on the surface of a resin foam layer while compressing it with a mold, and fusing the opposing inner surfaces of the parison. (JP-B-62-27978, JP-A-6-321449, etc.).

However, in the above-mentioned method of molding a multi-layer parison while compressing the multilayer parison, a combination of a resin constituting the non-foamed resin layer and a resin constituting the resin foamed layer which does not exhibit good adhesiveness is used. In the case of adopting the method described above, the molded body obtained by molding the multilayer parison in the mold by the method is removed from the mold and the burrs are removed. There is a problem that the resin foamed layer and the non-foamed resin layer are easily separated from each other as a starting point. This means that as the resin constituting the resin foam layer, it is possible to increase the magnification and thickness, select a polystyrene resin that is superior in heat insulation and versatility, and select the heat resistance, impact properties, and oil resistance of the polystyrene resin. In order to improve the resilience, a polyolefin-based resin or the like was selected as the resin constituting the non-foamed resin layer, which was remarkably exhibited.

The above problem can be solved by bonding a foamed resin layer of a polystyrene resin and a non-foamed resin layer of a polyolefin resin or the like with an adhesive layer such as one-component urethane interposed therebetween. However, since the molded product having such a configuration cannot be used as a recycled resin in the same product even if it is melt-kneaded again, it is not economical and is not suitable for actual production. Further, since there is a problem of odor depending on the type of the adhesive layer, the configuration cannot be adopted in actual production.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the prior art, the present invention provides a multilayer polystyrene resin foam molded article which does not require a complicated process of injecting a foam after producing a semi-molded article. With the goal. The present invention also provides a polystyrene resin foam layer without using a special adhesive, a layer made of a polyolefin resin, a layer made of a polyester resin, a polyolefin resin or a polyester resin, and a mixture of a polystyrene resin. Multi-layer polystyrene with a beautiful appearance and excellent light weight, mechanical strength, heat insulation, cushioning, vibration damping, oil resistance, impact resistance, recyclability, etc. An object of the present invention is to provide a resin foam molded article.

[0007]

The multilayer polystyrene resin foam molded article of the present invention comprises a multilayer parison having a mixed resin layer on the outer surface of a polystyrene resin foam layer, wherein at least a part of the inner surfaces of the parison are fused. A foamed molded product obtained by molding with a molding die so that the mixed resin layer is (1) 20 to 80% by weight of a polystyrene resin.
And (2) a mixture of 20 to 80% by weight of a polyolefin-based resin or polyester-based resin (however, the total of (1) and (2) is 100% by weight). It is preferable that the peel strength between the polystyrene resin foam layer and the mixed resin layer of the foam molded article is 100 (gf / 25 mm) or more.

In the present invention, (3) 20 to 80% by weight of the polystyrene resin is added to the outside of the polystyrene resin foam layer.
And (4) a mixture of 20 to 80% by weight of a polyolefin resin (however, the total of (3) and (4) is 100% by weight)
A multi-layer parison obtained by molding a multi-layer parison in which a polyolefin-based resin layer is laminated via a mixed resin layer made of a molding die such that the inner surfaces of the parison are at least partially fused to each other. Foamed articles. The polyolefin-based resin layer of the foamed molded product is preferably made of a polyolefin-based resin having a Vicat softening point of 112 ° C. or higher, and the peel strength between the polystyrene-based resin foamed layer and the polyolefin-based resin layer of the foamed molded product is 1
It is preferably at least 00 (gf / 25 mm).

In the present invention, (5) 20 to 80% by weight of the polystyrene resin is added to the outside of the polystyrene resin foam layer.
And (6) a polyester resin layer is laminated via a mixed resin layer composed of a mixture of 20 to 80% by weight of a polyester resin (however, the total of (5) and (6) is 100% by weight). The present invention also encompasses a multilayer polystyrene resin foam molded article obtained by molding a multilayer parison with a molding die such that the inner surfaces of the parison are fused at least in part. The polyester resin layer of the foamed molded product is preferably made of a polyester resin having a half-crystallization time of 30 minutes or more, and the peel strength between the polystyrene resin foamed layer and the polyester resin layer of the foamed molded product is 100 (gf). /twenty five
mm) or more.

[0010] The polystyrene resin foam layer of the above-mentioned multilayer polystyrene resin foam molded article is preferably made of a polystyrene resin having a Vicat softening point of 110 ° C or higher.

A phase structure index PI value representing a mixed state of a mixture of a polystyrene resin and a polyolefin resin or a polyester resin constituting a mixed resin layer of the multilayer polystyrene resin foam molded article is 0.7. <PI value <
It is preferably 1.3.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1A is a longitudinal sectional view showing an example of a multilayer polystyrene resin foam molded article of the present invention having a mixed resin layer on the outer surface of the foam layer, and FIG. It is a longitudinal cross-sectional view which shows an example of the multilayer polystyrene resin foam molded body of this invention in which the polyolefin resin layer, the polyester resin layer, etc. are laminated via the mixed resin layer. In FIGS. 1A and 1B, reference numeral 1 denotes a multilayer polystyrene resin foam molded article (hereinafter, referred to as “foam molded article”).
12, a foamed polystyrene resin foam layer (hereinafter, referred to as a "foamed layer of a foamed molded article"), 13 a mixed resin layer of the foamed molded article, and 14 in FIG. A polyolefin-based resin layer or a polyester-based resin layer (hereinafter, referred to as a “polymer layer of a foamed molded article”). As shown in FIGS. 1A and 1B, the foamed molded article 1 has a foamed layer 12 of a foamed molded article and a mixed resin layer 13 of a foamed molded article that covers the entire surface of the foamed layer 12.

The foam molded article 1 is formed by compressing a multilayer parison having a mixed resin layer on the outer surface of a polystyrene resin foam layer with a mold such as a mold. The multi-layer parison has a tubular shape or another hollow shape, and has a shape capable of exhibiting the same or similar function as a pre-formed one capable of blowing air while being sandwiched between molds by blow molding or the like. is there.

FIG. 2 shows an example of a multilayer parison according to the present invention.
(A) and (b) show. FIG. 2A is an explanatory view of a multi-layer parison having a mixed resin layer on the outer surface of a polystyrene resin foam layer, and FIG. 2B is a diagram illustrating a polyolefin resin layer outside the polystyrene resin foam layer via the mixed resin layer. It is explanatory drawing of the multilayer parison which has a resin layer or a polyester resin layer. 2 (a) and 2 (b), reference numeral 6 denotes a multi-layer parison, 2 denotes a polystyrene resin foam layer (hereinafter, referred to as a “foam layer”), 3 denotes a mixed resin layer, and FIG. Represents a polyolefin-based resin layer or a polyester-based resin layer or the like (hereinafter referred to as a “polymer layer”) provided as necessary. As the mixed resin layer 3 and the polymer layer 4, a non-foamed material or a density of 0.4 g / cm ³
The above-mentioned foam or inorganic-filled non-foam is preferably used.

[0015] In the present invention, the foam molded article 1 is shown in FIG.
As shown in (a) and (b), the foam layer 1 of the foam molded article 1
2, the foam layer 12 is a foam layer 2 of the multilayer parison 6.
It corresponds to. Further, the foamed molded article 1 has a skin covering the entire surface of the foamed layer 12 of the molded article, and the skin is basically composed of the mixed resin layer 13 of the foamed molded article or the mixed resin layer 13.
And a polymer layer 14 of a foam molded article, wherein the mixed resin layer 13 of the foam molded article corresponds to the mixed resin layer 3 of the multilayer parison 6, and the polymer layer 14 of the foam molded article is a polymer of the multilayer parison 6 It corresponds to layer 4.

The polystyrene resin used for the polystyrene resin foam layer 2 includes a styrene homopolymer and a copolymer, and the styrene monomer unit contained in the polymer is at least 25% by weight or more, preferably at least 25% by weight. 50% by weight or more.

A preferred polystyrene resin used in the present invention is a resin containing at least 25% by weight of a structural unit represented by the following general formula (1) in the resin.

Embedded image In the general formula (1), R represents a hydrogen atom or a methyl group; Z represents a halogen atom or a methyl group;
Is 0 or an integer of 1 to 3.

Examples of the polystyrene resin include polystyrene, rubber-modified polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene- Methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-methyl acrylate copolymer, styrene
Examples thereof include an ethyl acrylate copolymer, a styrene-maleic anhydride copolymer, a polystyrene-polyphenylene ether copolymer, and a mixture of polystyrene and polyphenylene ether.

For the purpose of improving the brittleness of the foam layer 2, the styrene-conjugated diene block copolymer or a hydrogenated product thereof is preferably blended with the polystyrene-based resin at a ratio of preferably less than 30% by weight, or polypropylene. It is also possible to use a resin blended with a polyolefin resin such as a high-density polyethylene or a high-density resin, preferably in a proportion of less than 20% by weight.

In the present invention, the Vicat softening point is 11
It is preferable to improve the heat resistance of the foam molded article 1 by using a polystyrene resin having a temperature of 0 ° C. or higher for the foam layer 2. In the present specification, the Vicat softening point of a resin refers to a value determined according to JIS K7206 (test load is A method, and heating rate of heat transfer medium is 50 ° C./hour).

The polystyrene resin used for the foamed layer 2 of the present invention has a melt viscosity of 190 ° C. and a shear rate of 100 ° C.
Under the condition of sec ^-1 , 1 at 200 poise or more
Less than 00000 poise, preferably 1000 to 50
000 poise. If the melt viscosity is smaller than the above range, the molten resin extruded from the die at the time of foaming may drop, and it may be difficult to obtain the foamed layer 2. On the other hand, if it exceeds the above range, the viscosity is too high and the extrusion pressure rises, so that extrusion foaming becomes difficult, and there is a possibility that a good quality foamed layer 2 may not be obtained.

The polystyrene resin used for the foamed layer 2 of the present invention has a melt flow rate under the conditions of 200 ° C. and a load of 5 kgf, preferably 0.8 to 30 g / 10 min and a melt tension of 5 to 40 gf. More preferably 1.0 to
It is preferable that the melt tension is 10 g / 10 min and the melt tension is 8 to 35 gf from the viewpoint of preventing the drawdown of the multilayer foamed parison 6 and increasing the magnification and thickness of the foamed layer 2. Has an excellent effect. Examples of such a polystyrene resin include a polystyrene resin having a branched structure.

The resin used for the mixed resin layer 3 is mainly composed of a mixture of a polystyrene resin and a polyolefin resin or polyester resin, and the mixture is preferably 60% by weight or more.

The polystyrene resin used for the mixed resin layer 3 may be the same resin as the polystyrene resin constituting the foamed layer 2. However, the polystyrene resin used for the mixed resin layer 3 does not need to be the same as the polystyrene resin used for the foamed layer 2.
It is appropriately selected from the above polystyrene resins in relation to the melt viscosity and the melt flow rate of the polyolefin resin or polyester resin to be mixed.

Examples of the polyolefin resin used in the mixed resin layer 3 include polyethylene resins such as low density polyethylene, high density polyethylene, and linear low density polyethylene, polypropylene, propylene-ethylene random copolymer, and propylene-1. Butene random copolymer,
One or a mixture of two or more selected from a polypropylene-based resin such as a propylene-ethylene-butene random copolymer and a propylene-ethylene block copolymer, and a cyclic polyolefin.

The polyolefin resin used in the mixed resin layer 3 preferably has a Vicat softening point of 112 ° C. or higher in terms of heat resistance, more preferably 120 ° C. or higher, and more specifically, polypropylene. Resins and high-density polyethylene resins are preferred. The upper limit of the Vicat softening point is not particularly limited, but is about 165 ° C.

The polyester resin used for the mixed resin layer 3 may be selected from polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and a copolyester of terephthalic acid, ethylene glycol and cyclohexanedimethanol. Mixtures of more than one species. Particularly, the product name “Eastar PETG67” manufactured by Eastman Chemical Co., Ltd.
Copolyester-based resins having a half-crystallization time of 30 minutes or longer, such as "63" and "Eastar PETG5011", are preferable because the recovered raw materials can be recycled as raw materials for the foamed layer and / or the mixed resin layer.

The half-crystallization time referred to in the present specification is measured using a MK-801 type crystallization rate measuring device manufactured by Metron Co., Ltd. (formerly Kotaki Shoji Co., Ltd.). The crystallization rate measuring device is an apparatus for determining the degree of crystallization from the relationship between crystallization of a sample and birefringence of light.

The measurement of the half-crystallization time was performed when the thickness was 0.1 ± 0.1%.
A square film of 0.02 mm and 15 × 15 mm was prepared, and the film sandwiched between cover glasses for a microscope was heated to 300 ° C. in advance as a measurement sample, and then the crystallization bath was set to 100 ° C. And set the indicated value of the luminance of the light source lamp to 3 V for measurement.

The half crystallization time referred to in the present specification is obtained by reading a value A at which the amount of light due to birefringence is constant from the curve on the graph shown in FIG. This value is obtained by reading a value C on the curve on the graph corresponding to the value B on the vertical axis on the graph obtained by multiplying the value by 0.5 and obtaining the value D on the horizontal axis on the graph corresponding to C.
In addition, E in FIG. 3 is the crystallization bath set temperature, and the polygonal line (II) is the crystallization bath temperature.

The mixture of polystyrene resin and polyolefin resin or polyester resin constituting the main components of the mixed resin layer 3 comprises (1) 20 to 80% by weight of polystyrene resin and (2) polyolefin resin or A mixture with 20 to 80% by weight of a polyester resin (however,
(The sum of (1) and (2) is preferably 100% by weight), and (1) 40 to 80% by weight of a polystyrene resin.
And (2) a mixture of 20 to 60% by weight of a polyolefin resin or a polyester resin (provided that (1) and (2)
Is more preferably 100% by weight) in terms of adhesion to the foam layer, oil resistance of the mixed resin layer, and the like.

If the polystyrene resin in the mixture constituting the mixed resin layer 3 is less than 20% by weight, the foamed layer 2
And the mixed resin layer 3 becomes insufficient in adhesiveness, and after the multilayer parison 6 is formed, the foamed layer 12 of the foamed molded article and the mixed resin layer 13 of the foamed molded article undergo interfacial peeling from the cut portion obtained by cutting off the burrs. And a good foamed molded article cannot be obtained.

On the other hand, when the amount of the polystyrene resin exceeds 80% by weight, the adhesiveness between the foamed layer 2 and the mixed resin layer 3 is satisfied, but the polystyrene constituting the mixed resin layer 3 is formed outside the mixed resin layer 3. Even if a polymer layer 4 made of a polymer exhibiting thermal adhesion that can withstand practical use with a polyolefin-based resin or polyester-based resin mixed with a resin-based resin, the polymer layer 4 and the mixed resin layer 3 Adhesive properties became insufficient, and after forming the multilayer parison 6, the polymer layer 14 of the foamed molded article and the mixed resin layer 13 of the foamed molded article were separated from the cut portion obtained by cutting off the burrs, resulting in good molding. It does not become a body. On the other hand, when the polystyrene-based resin exceeds 80% by weight, functions such as oil resistance become insufficient.

A compatibilizer can be added to the mixed resin layer 3 of the present invention. As the compatibilizer, any one can be used as long as it can compatibilize the polystyrene resin and the polyolefin resin or the polyester resin, and various conventionally known ones can be used. And styrene-olefin copolymers are preferred. The styrene-based thermoplastic elastomer includes SB
S-type or SIS-type, SEBS-type or SEPS-type, and the like are included.

The SBS or SIS type has a structure in which a hard segment has a polystyrene crystal phase and a soft segment has polybutadiene or polyisoprene copolymerized in a block manner. On the other hand, the above SEBS and SEPS-based products are
It is obtained by highly hydrogenating polybutadiene and polyisoprene contained in S-based compounds to saturate the double bonds in the main chain. In addition, these SEBS systems, SEPS
Styrene-based thermoplastic elastomers such as styrene-based, SBS-based, and SIS-based thermoplastic elastomers are described in "Plastic Age", No. 10
The details are described on pages 1 to 106 (June 1985).

Examples of the styrene-olefin copolymer include a graft copolymer of ethylene and styrene, a graft copolymer of propylene and styrene, a graft copolymer of ethylene-glycidyl methacrylate copolymer and styrene, and ethylene-ethyl. Graft copolymer of acrylate copolymer and styrene, graft copolymer of ethylene-vinyl acetate copolymer and styrene, graft copolymer of ethylene-ethyl acrylate-maleic anhydride copolymer and styrene, ethylene and methyl methacrylate Graft copolymer of ethylene-glycidyl methacrylate copolymer and methyl methacrylate, graft copolymer of ethylene-ethyl acrylate copolymer and methyl methacrylate, ethylene-vinyl acetate copolymer and methyl methacrylate Graft copolymer of ethylene-ethyl acrylate-maleic anhydride copolymer and methyl methacrylate, graft copolymer of ethylene and acrylonitrile-styrene copolymer, propylene and acrylonitrile-styrene copolymer Graft copolymer, graft copolymer of ethylene-glycidyl methacrylate copolymer and acrylonitrile-styrene copolymer, graft copolymer of ethylene-ethyl acrylate copolymer and acrylonitrile-styrene copolymer, ethylene-vinyl acetate copolymer Graft copolymer of polymer and acrylonitrile-styrene copolymer, graft copolymer of ethylene-ethyl acrylate-maleic anhydride copolymer and acrylonitrile-styrene copolymer, and styrene-ethylene lander Copolymer, styrene - propylene random copolymer and the like.

The compatibilizer is a mixture 1 of a polystyrene resin and a polyolefin resin or polyester resin.
0.1 to 40 parts by weight per 100 parts by weight, preferably 0.1 to 40 parts by weight.
It is preferable to add in a ratio of 5 to 10 parts by weight. In particular, in the case of a styrene-based thermoplastic elastomer,
Preferably, it is added in a proportion of 30 parts by weight.

When the compatibilizer made of the above-mentioned styrene-based thermoplastic elastomer is added, the adhesion between the polystyrene-based resin foam layer 2 and the mixed resin layer 3 is improved, and the impact strength and the impact strength of the foam molded article 1 of the present invention are improved. Brittleness is also improved. In addition, when the polymer layer 4 is provided outside the mixed resin layer 3, the adhesion between the mixed resin layer 3 and the polymer layer 4 is also improved.

The melt flow rate of the mixture used for the mixed resin layer 3 is preferably 0.15 to 30 (g / 10
Min), more preferably 0.5 to 12 (g / 10 min), and within this range, the same as the melt flow rate of the polystyrene resin used for the foamed layer 2, or a foaming agent mixed with the polystyrene resin. In consideration of the plasticizing effect of the polystyrene resin, a somewhat higher value is selected, with "melt flow rate of polystyrene resin +10 (g / 10 min)" as the upper limit, rather than the melt flow rate of the polystyrene resin. Is preferred. The melt flow rate of the mixture is a value measured at 200 ° C. under a load of 5 kgf.

If the melt flow rate of the mixture is too low, the surface smoothness of the multilayer parison 6 may be deteriorated due to poor fluidity in the die, and in some cases, melt fracture may occur. Further, since the heat generation in the die also increases, the temperature of the resin increases, and the laminated foam layer 2
May be destroyed, and the closed cell rate may decrease.
On the other hand, if the melt flow rate of the mixture is too high,
Generally, since the melt tension is also reduced and the drawdown is increased, it becomes difficult to produce a large multilayer parison 6,
There is a possibility that a large foam molded article cannot be obtained.
In addition, since the foaming force of the bubbles in the foamed layer 2 is large, the bubbles may rise to the mixed resin layer 3, and the surface of the mixed resin layer 3 may become uneven, and the appearance may be deteriorated.

The polymer used for the polymer layer 4 is, for example, polyethylene resin such as low density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, propylene-ethylene random copolymer, propylene-1 butene. Random copolymer, propylene-ethylene block copolymer, polypropylene resin such as propylene-1 butene block copolymer, cyclic polyolefin, polycarbonate resin, polyester resin, styrene thermoplastic elastomer, olefin thermoplastic elastomer, Examples include a thermoplastic polymer composed of one or a mixture of two or more selected from polyester-based thermoplastic elastomers. Further, the polymer layer 4 of a single layer or a multi-layer made of these polymers needs to have thermal adhesiveness to the mixed resin layer 3 on the lamination surface with the mixed resin layer 3.

Among the above thermoplastic polymers, polyolefin resins and polyester resins are preferred, and polypropylene resins are preferred in terms of heat resistance and impact resistance at room temperature, and impact resistance under low temperature conditions. Linear low density polyethylene is preferred, high density polyethylene is preferred in terms of heat resistance and impact resistance under low temperature conditions, and polyester resin is preferred in terms of gas barrier properties and impact resistance at room temperature.

In the foamed molded article 1 of the present invention, the peel strength between the foamed layer 12 of the foamed molded article and the mixed resin layer 13 of the foamed molded article is preferably 100 (gf / 25 mm) or more. (Gf / 25 mm) or more, and particularly preferably a large peel strength of 200 (gf / 25 mm) or more. Also,
In the foamed molded article 1 in which the polymer layer 14 of the foamed molded article is laminated outside the foamed layer 12 of the foamed molded article via the mixed resin layer 13 of the foamed molded article, the foamed layer 12 and the polymer layer Peeling strength between 14 and 100 (gf / 25 mm)
And preferably 150 (gf / 25 mm)
More preferably, it is more than 200 (gf / 25m
It is particularly preferred to have a large peel strength of at least m). The upper limit of the peel strength is not particularly limited, but is usually about 3000 (gf / 25 mm). The foam molded article having such a large delamination strength has been developed for the first time by the present inventors.

The above adhesive strength is 100 (gf / 25 mm)
If it is less than 10 mm, the foamed layer 12 of the foamed molded article and the mixed resin layer 13 of the foamed molded article 13
When the mixed resin layer 13 of the foamed molded article and the polymer layer 14 of the foamed molded article are peeled off, or after the multilayer parison 6 is molded, the foamed layer 12 of the foamed molded article is cut from the cut portion where the burr is cut off. There is a concern that the mixed resin layer 13 of the foamed molded article or the mixed resin layer 13 of the foamed molded article and the polymer layer 14 of the foamed molded article may undergo interface separation.

In the present specification, the strip strength between the foamed layer 12 of the foamed molded article and the mixed resin layer 13 of the foamed molded article was determined by cutting a strip-shaped test piece having a width of 25 mm from the obtained foamed molded article 1. According to JIS Z0237, peeling speed condition 30
It is a value (gf / 25 mm) determined by measuring in a 90 ° peel test at 0 mm / min. In the case of the foamed molded article 1 having the mixed resin layer 13 of the foamed molded article and the polymer layer 14 of the foamed molded article, a test piece similar to the above-described test piece is cut out from the foamed molded article 1 and foamed by the upper grip. Only the polymer layer 14 of the molded article is pulled, and a peel test is performed in the same manner as described above, and the foamed layer 12 of the foamed molded article and the mixed resin layer 1 of the foamed molded article 1
3, or a value (gf / 25 mm) obtained by determining the strength at which one of the mixed resin layer 13 of the foamed molded article and the polymer layer 14 of the foamed molded article is peeled off.

However, when it is not possible to cut out a strip test piece having a width of 25 mm, a strip test piece having a width as wide as possible is cut out and the above-mentioned peeling test is performed, and the peeling strength per width of the cut test piece is obtained. The value is multiplied by “25 / coefficient of width (mm) of cut specimen” to obtain a peel strength per 25 mm width (gf / 25 mm).

As a method for increasing the delamination strength of the foamed molded article 1 of the present invention as described above, a phase structure index PI value representing the mixed state of the mixture constituting the mixed resin layer 3 of the multilayer parison 6 is used. More than 0.7 and less than 1.3, preferably 0.1.
The adjustment should be within the range of 8 to 1.2.

The phase structure index PI value of the mixed resin layer indicates a mixed state of the polystyrene resin and the polyolefin resin or the polyester resin of the mixed resin layer.
It is defined by the following equation (7).

[Number 1] PI value _{= (η A × φ B)} / (η B × φ A) ............ (7)

In the above formula (7), φ _A is the volume fraction of the polystyrene resin phase in the mixed resin layer, and η _A is 180
° C, the melt viscosity of the polystyrene resin at a shear rate of 100 sec ^-1 , φ _B is the volume fraction of the polyolefin resin phase or polyester resin phase in the mixed resin layer, and η _B is 1
The melt viscosity of a polyolefin resin or polyester resin at 80 ° C. and a shear rate of 100 sec ⁻¹ .

According to the study of the present inventors, when the PI value of the mixed resin layer 3 becomes 0.7 or less, the polyolefin resin or the polyester resin in the mixed resin layer 3 is covered with the polystyrene resin. Hardly exposed on the adhesive surface,
Foam layer 12 of foam molded article and mixed resin layer 13 of foam molded article
Although the peel strength of the foamed molded article 1 shows a high value, the oil resistance, impact strength, and the like of the foam molded article 1 may be insufficient.

Further, when a polyolefin-based resin layer or a polyester-based resin layer is provided outside the mixed resin layer 13 of the foamed molded product, the peel strength between the layers becomes insufficient, and the multilayer parison 6 is formed by molding with a mold. In a foam molded article such as a container to be formed, a mixed resin layer 13 of the foam molded article and a polymer layer 14 of the foam molded article are cut from a portion where the burr of the foam molded article is cut off.
Are easily peeled off.

On the other hand, when the PI value becomes 1.3 or more, the polystyrene resin in the mixed resin layer 3 is covered with the polyolefin resin or the polyester resin, and is hardly exposed to the adhesive surface. The peel strength between the layer 13 and the foamed layer 12 of the foamed molded article becomes insufficient, and in a molded article such as a container obtained from the multilayer parison 6, the foamed layer 12 of the foamed molded article is cut from a portion where the burr of the foamed molded article is cut off. And the mixed resin layer 13 of the foamed molded body easily peels off.

When the PI value is in the range of more than 0.7 and less than 1.3, the foamed molded article 1 formed from the multilayer parison 6 having the mixed resin layer 3 on the outer surface of the foamed layer 3 has a high foaming efficiency. The peel strength between the foamed layer 12 of the molded article and the mixed resin layer 13 of the foamed molded article is high and excellent, and the foamed molded article 1 having the polymer layer 14 of the foamed molded article on the outer side is excellent. The peel strength between the foamed layer 12 and the polymer layer 14 of the foamed molded article made of the polyolefin-based resin layer or the polyester-based resin layer is high and excellent.

In the foamed molded article 1 of the present invention, a metal layer, a fiber layer such as a nonwoven fabric or a woven fabric, etc. may be provided further outside the mixed resin layer 13 of the foamed molded article or the polymer layer 14 of the foamed molded article.

The foamed layer 2, the mixed resin layer 3, and the polymer layer 4 of the multilayer parison 6 are made of a resin or a polymer constituting these layers, and are provided with a bubble regulator, an infrared absorber, an infrared reflector, Various additives such as a fuel, a fluidity improver, a weathering agent, a colorant, a heat stabilizer, an antioxidant, a filler, and a rubber may be appropriately blended as necessary. Further, as the polymer layer 4, it is preferable to use polypropylene or high-density polyethylene having a high melt tension, since a foamed molded article 1 having a good appearance can be obtained.

The use of an olefin-based thermoplastic elastomer or a styrene-based thermoplastic elastomer as the polymer layer 4 is preferable because the impact resistance of the obtained foamed molded article 1 is further improved.

The thickness of the skin comprising only the mixed resin layer 13 of the foamed molded article covering the foamed layer 12 of the foamed molded article of the present invention or the mixed resin layer 13 of the foamed molded article and the polymer layer 14 of the foamed molded article is as follows. It is preferably from 100 μm to 10 mm, more preferably from 100 μm to 7 mm. The skin thickness is 100μ
If it is less than m, the surface smoothness is reduced, and the surface appearance of the foam molded article 1 may be inferior. The skin thickness is 10m
When m exceeds m, the weight of the foamed molded article 1 as a whole increases, so that it is difficult to say that the foamed molded article 1 is lightweight depending on the application, and the closed cell ratio of the foam layer 12 of the foamed molded article may be reduced.

The density of the foam layer 12 of the foam molded article is 20 to 5
00 kg / m ³ is preferable, and more preferably 20 to 4 kg / m ^3.
00 kg / m ³ . When the density of the foam layer 12 of the foamed molded body exceeds 500 kg / m ³ , it is difficult to say that the foam is lightweight.
In addition, physical properties such as heat insulation may be reduced. When the density of the foam layer 12 of the foam molded article is less than 20 kg / m ³ ,
Since the cell membrane constituting the foam layer 12 becomes thin, there is a possibility that a good foam molded article 1 cannot be obtained.

The density of the foamed layer 12 of the foamed molded article is determined by cutting out a part of the foamed layer 12 from the foamed molded article 1 and measuring the weight of the sample cut out of the foamed layer 12 of the foamed molded article. It is calculated by dividing by the volume determined from the dimensions. The thickness of each layer can be determined from the cross-section of the foam molded article (enlarged by a microscope as necessary, and an enlarged projected view is used). In addition, since the density of the foamed layer of the foamed molded article may be different for each part of the foamed molded article, a sample of the foamed layer 12 of the foamed molded article is cut out from ten or more places such as the bottom face and the side face of the foamed molded article. The density is measured for each sample, and the arithmetic average of the value excluding the maximum value and the minimum value is defined as the density of the foam layer 12 of the foam molded article.

The density of the foamed molded article 1 of the present invention is generally 20 to 800 kg / m ³ , preferably 25 to 4 kg / m ^3.
00 kg / m ³ . The density of the foam molding 1 is 800k
If it exceeds g / m ³ , the lightness and the heat insulation may be reduced. When the density of the foamed molded article 1 is less than 20 kg / m ³ , mechanical properties such as compressive strength may be reduced.

The density of the foamed molded article 1 is determined by measuring the volume of the foamed molded article submerged in water (however, even if there are voids inside the foamed molded article, (The volume of the void is not subtracted.) It is obtained by dividing the weight of the foamed molded article 1 by the previously obtained volume.

The foamed layer 2 of the multilayer parison 6 formed as the foamed layer 12 of the foamed molded article in the present invention is obtained by extrusion foaming a foamable molten resin obtained by adding a foaming agent to the above-mentioned polystyrene resin. can get. As the foaming agent, any of an inorganic foaming agent, a volatile foaming agent, and a decomposition-type foaming agent can be used. However, in order to obtain a foamed layer 12 of a foamed molded article having a high expansion ratio, a volatile foaming agent must be used. Is preferred. Examples of the inorganic foaming agent include nitrogen and carbon dioxide. Examples of the volatile foaming agent include propane, normal butane, isobutane, normal pentane, isopentane, normal hexane, isohexane, aliphatic hydrocarbons such as cyclohexane, methyl chloride, chlorinated hydrocarbons such as ethyl chloride, 1,1,1, and the like. Examples include fluorinated hydrocarbons such as 2-tetrafluoroethane and 1,1-difluoroethane. Examples of the decomposition type foaming agent include azodicarbonamide.
The above foaming agents can be used in combination of two or more,
Further, it is also possible to use a decomposition type foaming agent together with an inorganic foaming agent and a volatile foaming agent for the purpose of adjusting the air bubbles.

An example of a method for manufacturing the foam molded article 1 of the present invention will be described with reference to FIG. In order to manufacture the multilayer parison 6, as shown in FIG. 4, the base resin forming each layer of the multilayer parison 6 is melt-kneaded by a separate extruder (not shown), and these are laminated and merged in a die 21. The multi-layer parison 6 is obtained by extruding to a low pressure region while the pressure is being increased.
If necessary, an accumulator may be provided between the extruder and the die 21 or in the die 21.

In order to obtain the foamed molded article 1 from the multilayer parison 6, after forming the multilayer parison 6, as shown in FIG. 4, the divided mold 22a is sandwiched so as to sandwich the extruded multilayer parison 6 from both sides. 22b is closed. When the mold is closed, the foamed multi-layer parison 6 is compressed on the mold inner surfaces 23a and 23b, and adheres to the mold inner surface while deforming flat. Next, by closing the mold as shown in FIG. 5, at least a part of the inner surfaces of the multilayer parison 6 is fused to form the multilayer parison 6 foamed in the cavity. The foam molded article 1 is obtained.

Further, as shown in FIG. 4, by providing a depressurizing pipe 24 in the die, a die formed so as to be able to depressurize between the inner surfaces 23a and 23b of the die and the outer surface of the multilayer parison 6 is used. When closing the mold while depressurizing and molding,
When the outer surface of the multilayer parison 6 and the inner surface of the mold are closely adhered to each other, a foam molded article 1 having a good shape of the mold can be obtained, and when a mold having a pattern on the inner surface of the mold is used. In addition, the mold pattern transferability of the surface of the foam molded article 1 is also improved.

Immediately after the multi-layer parison is extruded, the multi-layer parison may be closed by a parison pinch, and the multi-layer parison expanded by pre-blowing may be formed as described above.

When the multi-layer parison 6 is formed by deep drawing, as shown in FIGS. 6 (a) and 6 (b), the four side surfaces 25 of the female mold 22b can be moved about the bottom surface 26. By constructing the female mold 22b, the female mold 22b can be assembled and deployed, and while the female mold 22b is deployed, the side surface 25 of the female mold 22b is moved to mold the female mold 22. Preferably, the male mold 22a and the female mold 22b are closed and molded.

FIGS. 4 to 6 are explanatory views conceptually showing an example of the production of a foamed molded article. The specific operation procedure for producing the foamed molded article of the present invention is shown in FIGS. It is not limited to what you do.

In the present invention, when the foaming ratio of the foamed layer 2 and the mixed resin layer 3 and the foamed layer 2 when extruding the polymer layer 4 from a die are high, the mixed resin layer 3 and / or the polymer If the layer 4 is not easily stretched, the tip of the multilayer parison 6 may be turned immediately after the multilayer parison 6 is extruded from the die. The turning of the tip of this multi-layer parison 6
This phenomenon is caused by the fact that the expansion of the mixed resin layer 3 and the like cannot follow the foamed layer 2 at a high magnification at the tip of the multilayer parison. What happens. After the resin forming the multilayer parison 6 is extruded to some extent,
Since the multilayer parison 6 itself is pulled downward by its own weight, no turn-over occurs.

When the tip of the multi-layer parison 6 is turned up, the turned-up portion cannot be used for molding. Therefore, the multi-layer parison 6 is extruded for a longer time, and only the portion where the turn is not generated is removed. It is necessary to obtain a foamed molded article 1 of a required size by molding. In this case, since the turned-up portion becomes a large burr, not only is the efficiency inefficient, but also an increase in the weight of the parison causes adverse effects such as drawdown.

In order to prevent the above turning, the mixed resin layer 3
Alternatively, the start of extrusion of the polymer layer 4 may be earlier than the start of extrusion of the foamed layer 2, the tip of the multilayer parison 6 may be formed without turning over, and then the entire layer may be extruded. Immediately after the tip of the multilayer parison 6 is extruded from the die, the lower tip of the multilayer parison 6 is pressed from the outside of the multilayer parison 6 in the mold clamping direction at the lower part of the die, so that at least a part of the inner surface of the multilayer parison 6 is formed. It is also possible to prevent the tip of the multilayer parison 6 from being turned up by using a technique such as bonding. If the tip of the multilayer parison 6 is prevented from being turned up by adopting such a method, the molding loss can be reduced, so that the extruded multilayer parison can be used effectively.

In the present invention, as described above, the molded foam 1 can be obtained by sandwiching the multilayer parison 6 in a molding die and compressing and molding. By using the multi-layer parison 6 in such a manner to obtain the foamed molded article 1, the foamed layer 12 of the foamed molded article and the mixed resin layer 13 of the foamed molded article, or the foamed layer 12 and the mixed resin layer The adhesion between the polymer layer 13 and the polymer layer 14 of the foamed molded article is good, and the peel strength can be increased. In addition, the foam molding 1
The thickness of the mixed resin layer 13 or the mixed resin layer 13 and the polymer layer 14 of the foamed molded article can be made more uniform, and the foamed layer 13 of the foamed molded article has a higher expansion ratio. There is an advantage that a product having a higher thickness and a product having a more uniform magnification can be easily obtained.

In the present invention, for example, FIG.
(A) As shown in FIG. 1 (b), when the inner surfaces of the multi-layer parison 6 are completely adhered to each other and the whole is fused and molded, there is no void inside the foamed molded body. This is a preferred embodiment in terms of dimensional stability and improvement of mechanical properties. The fusion ratio of the inner surface of the foamed molded product is represented by a fusion portion area ratio (%) in the present specification, and the fusion portion area ratio is 60% in terms of dimensional stability and improvement of mechanical properties. And more preferably 80% or more, and more preferably 9% or more.
Those having 5% or more are particularly preferred. The method for measuring the fused area ratio is as follows.

The foam molded article is cut in a direction perpendicular to the extrusion direction of the multilayer parison and parallel to the compression direction of the multilayer parison mold at the time of manufacturing the foam molded article so as to be equally divided into ten at equal intervals.
Next, the foam molded body is placed so that the cut surface of the cut foam molded body is located in the left-right direction in the order in which the foam molded body was formed. The length (mm) of the portion where the inner surfaces of the multilayer parison used to form the foam molded body are fused together is determined,
A value obtained by doubling this is defined as A (mm) as the length of the fused portion. Further, in the case where a gap is formed on the cut surface on the right side without the inner surfaces of the multilayer parison being fused, the inner peripheral length of the gap is B (mm). In addition, when there are a plurality of the fused portion lengths and / or voids in each of the cut surfaces, the fused portion length or the inner peripheral length of the void portion is obtained for each location, and the total of each is A or B. I do. Next, [A /
(A + B)] × 100, the fused area ratio (%) of each cut surface is determined. In addition, the said area ratio of a foaming molding becomes 100% in the state where there is no void part. Then, the arithmetic average value of the area ratio of the fused portion of each of the cut surfaces (excluding the cut surface where the inner surface fused portion itself of the multilayer parison does not exist) is defined as the fused portion area ratio (%) of the foam molded article. .

The foam molded article of the present invention is JIS K7211.
The one having a 50% breaking energy of 1 J or more in a falling weight impact test at room temperature, which is required in the above, is preferable. Furthermore, the 50% breaking energy by the falling weight impact test at low temperature is 0.5 J
Above, especially 0.7J or more is preferable.

In the falling weight impact test at room temperature or low temperature, 5
The 0% destruction energy was obtained by cutting a test piece cut from a foam molded article having a size of 100 mm in length and 100 mm in width left for 24 hours in a constant temperature and humidity room at a temperature of 23 ° C. and a humidity of 55% or a low temperature bath at −40 ° C. for 24 hours. A drop weight impact test is performed in a constant temperature and humidity room at 55 ° C. and a humidity of 55%, and the weight drop is determined by a calculation method according to JIS K7211. In the case of the falling weight impact test at a low temperature, the measurement is performed within 2 seconds after removing each test piece from the low temperature chamber. The tester was No. No. manufactured by Toyo Seiki Seisaku-sho, Ltd. 6
21 Drop weight impact tester was used, and the weight used was JIS
A spherical weight of the nominal ball type 2 (diameter 63 mm, mass 1 kg) specified in K7211 is used.

FIGS. 1A and 1B are drawings showing an example of the cross-sectional shape of the foamed molded article of the present invention. Fig. 1 (a), (b)
Is a container-shaped foam molded article obtained by completely fusing the inner surfaces of the foam layers of the multilayer foam parison with each other, and molding with a mold so that the container space 15 is formed.

When a container is obtained as a foamed molded article,
The density of the shape is 30 to 400 kg / m ^ThreeBy doing
Lightweight and excellent in heat insulation, mixing of foam moldings
The thickness of the resin layer 13 or the mixed resin layer 13 of the foam molded article
And the total thickness of the polymer layer 14 of the foamed molded article is 2
By setting the thickness to 00 to 5000 μm, durability and surface flatness are improved.
Obtain a container with high lubricity, balanced appearance and light weight
Can be

[0079]

The present invention will be described below in more detail with reference to examples. Example 1 A general-purpose polystyrene (Stylon G9802 manufactured by A & M Styrene Co., Ltd.) was used as a polystyrene-based resin, and 0.16% by weight of talc was further mixed as a cell regulator into an extruder and melted and kneaded. A foaming agent (a mixture of isobutane and normal butane at a weight ratio of 35:65) in the amount shown in Table 1 was pressed into an extruder and kneaded to obtain a foamable melt for forming a foam layer.

[0080]

[Table 1]

On the other hand, low-density polyethylene (NS-1 manufactured by Nippon Unicar Co., Ltd.) as a polyolefin resin, general-purpose polystyrene (Stylon 679 manufactured by A & M Styrene Co., Ltd.) as a polystyrene resin, and styrene-based heat A non-foamable melt for forming a mixed resin layer with a plastic elastomer (Tuftec H1041 manufactured by Asahi Kasei Kogyo Co., Ltd.) mixed at the compounding amount shown in Table 1 is supplied to another extruder and melt-kneaded. did.

Next, the melt kneaded by each extruder is filled into each accumulator provided between the extruder and the die, and after the filling is completed, the filled non-foamable melt and the foamable The melt was injected by an accumulator so as to be laminated and merged in the die, and was extruded from the die to obtain a multilayer parison in which the mixed resin layer was laminated on the outer surface of the foam layer.

Next, the extruded multilayer parison is
Closed so as to be sandwiched by the multi-part mold shown in FIG. 6 installed immediately below the die, deform the multilayer parison into a flat shape on the inner surface of the cavity, and further reduce the pressure inside the mold to mold the multilayer parison into a mold. It adhered in the plane. The multi-layer parison was formed in the mold as described above, and was further cooled and released to take out a foam molded article. In addition, the above-mentioned mold used was a mold whose inner surface was subjected to satin finish processing.

The foam molded article thus obtained (a container having a truncated conical shape having an opening of 300 mm long × 260 mm wide, a bottom part of 260 mm long × 180 mm wide, a height of 110 mm and a wall thickness of about 20 mm) Shape) had good appearance without any shrinkage or deformation.

Examples 2 to 7 Using the base materials shown in Table 1 and the same foaming agent as in Example 1,
A foam molded article was produced in the same manner as in Example 1 with the compounding amounts shown in Table 1. The foam molded body obtained in this way shrinks,
The appearance without deformation was good.

Example 8 Using the base materials shown in Table 1 and the same foaming agent as in Example 1,
With the compounding amounts shown in Table 1, a foamable melt for forming a foamed layer and a non-foamable melt for forming a mixed resin layer were produced in an extruder in the same manner as in Example 1. Furthermore, low density polyethylene (800 Nippon Unicar Co., Ltd.)
8) was further supplied to another extruder and melt-kneaded to obtain a non-foamable melt for forming a polymer layer.

A foamable melt for forming the foamed layer, a non-foamable melt for forming the mixed resin layer, and a non-foamable melt for forming the polymer layer are die-bonded. Injected by an accumulator provided between the extruder and the die so that they are merged within, extruded from the die, and a polymer layer made of a non-foamed resin is laminated on the outer surface of the foamed layer via a mixed resin layer. A multilayer parison was obtained. Next, the multi-layer parison is placed just below the die in FIG.
The molding, cooling, and release were performed in the same manner as in Example 1 using a mold of the type shown in FIG. The foam molded article thus obtained had a good appearance without any shrinkage or deformation.

Examples 9 to 12 Using the base materials shown in Table 1 and the same foaming agent as in Example 1,
A foam molded article was produced in the same manner as in Example 8 with the compounding amounts shown in Table 1. The foam molded body obtained in this way shrinks,
The appearance without deformation was good.

Comparative Example 1 Using the base material shown in Table 1 and the same foaming agent as in Example 1,
With the compounding amounts shown in Table 1, a foamable melt for forming a foamed layer and a non-foamable melt for forming a polymer layer were prepared in the same manner as in Example 8 (provided that the mixed resin layer was used). Are not formed), they are injected by an accumulator provided between the extruder and the die so as to be laminated and merged in the die, and extruded from the die, and a multi-layer parison having a polymer layer laminated on the outer surface of a foam layer I got Next, a foam molded article was manufactured in the same manner as in Example 1.

The foamed molded article thus obtained had a good appearance without any shrinkage or deformation, but was insufficient in oil resistance and impact resistance.

Comparative Example 2 Using the base material shown in Table 1 and the same foaming agent as in Example 1,
A foam molded article was produced in the same manner as in Comparative Example 1 with the compounding amounts shown in Table 1. However, although a molded article was obtained, the foamed layer and the polymer layer caused interfacial peeling from the cut portion where the burr was cut off, and a good foamed molded article could not be obtained.

Comparative Example 3 Using the base materials shown in Table 1 and the same foaming agent as in Example 1,
With the compounding amounts shown in Table 1, a foam molded article was produced in the same manner as in Example 1, and a molded article having a good appearance was obtained, but the oil resistance and impact resistance were insufficient.

Comparative Example 4 Using the base material shown in Table 1 and the same foaming agent as in Example 1,
With the compounding amount shown in Table 1, a foam molded article was produced in the same manner as in Example 1. However, although the molded article was obtained, the foamed layer and the mixed resin layer caused interfacial peeling from the cut portion obtained by cutting off the burr,
A good foam molded article was not obtained.

Comparative Example 5 Using the base materials shown in Table 1 and the same foaming agent as in Example 1,
With the compounding amounts shown in Table 1, the mixed resin layer was changed to a polystyrene resin layer, and a foam molded article was manufactured in the same manner as in Comparative Example 4.
Although the obtained foamed molded article had a good appearance, it was insufficient in oil resistance.

Comparative Examples 6 and 7 Using the base materials shown in Table 1 and the same foaming agent as in Example 1,
A foam molded article was produced in the same manner as in Example 8 with the compounding amounts shown in Table 1. Although a molded article was obtained, the polymer layer and the foamed layer were peeled off from the cut portion where the burr was cut off, and a good foamed molded article was not obtained. In Comparative Example 6, interface peeling occurred between the mixed resin layer and the polymer layer, and in Comparative Example 7, interfacial peeling occurred between the foamed layer and the mixed resin layer.

Table 2 shows the results obtained by measuring the density, solvent resistance, impact resistance at ordinary and low temperatures, and peel strength of the foamed molded articles obtained in Examples 1 to 12 and Comparative Examples 1 to 7. still,
The fused area ratios of the foamed molded articles obtained in Examples 1 to 12 were all 100%.

[0097]

[Table 2]

Table 3 shows the Vicat softening point, resin density and melt viscosity of the various substrates used in Examples 1 to 12 and Comparative Examples 1 to 7. Table 4 shows the types of base materials, manufacturer names, and grade names indicated by symbols in Tables 1 and 3.

[0099]

[Table 3] -: Not measured

[0100]

[Table 4]

A calculation example of the PI value of the mixed resin layer shown in Table 1 is shown below for the case of Example 1. PI value _{= (η A × φ B)} / (η B × φ A) η A = PS (2) Viscosity = 10100 [poise] of φ _A = PS (2) of the volume fraction η _B = LDPE (1) Viscosity = 16100 [poise] φ _B = volume fraction of LDPE (1)

[0102] _{Here, φ A = (W A /} ρ A) / (W A / ρ A + W B / ρ B) = (0.4 / 1.05) / (0.4 / 1.05 + 0 _{.6 / 0.92) = 0.37 φ B} = (W B / ρ B) / (W A / ρ A + W B / ρ B) = (0.6 / 0.92) / (0.4 / 1.05 + 0.6 / 0.92) = 0.63 W a = resin density of PS (amounts shown in Table 1 of 2) _{(wt%) / 100 = 0.4 ρ a} = PS (2) = 1.05 W _B = LDPE resin density = 0.92 in the amount shown in Table 1 (1) _{(wt%) / 100 = 0.6 ρ B} = LDPE (1)

Therefore, PI value = (η _A × φ _B ) / (η _B × φ _A ) = (10100 × 0.63) / (16100 × 0.37) = 1.07

[0104] The melt viscosity in the present specification was measured by using a "Rheobis 2100" manufactured by Chiast with an orifice having an inner diameter of 1 mm and a length of 10 mm, and a shear rate of 10 mm.
It is a value measured under the conditions of ⁰ sec ⁻¹ and a resin temperature of 180 ° C.

The evaluation of the foam molded articles in Table 2 was performed as follows.

After the multilayer parison is molded by sandwiching it between molds, it is taken out of the mold, and the burr-cut portion from which the burr has been removed is used to form a foamed foam layer and a mixed resin layer of a foamed molded article, or a foamed molded article. When the interfacial delamination occurs between the mixed resin layer and the polymer layer of the foamed molded article, and a good foamed molded article cannot be obtained, ×, the burr cut portion is properly fused, and a good one is represented by ○. Was evaluated.

Solvent resistance: Solvent resistance was measured by pouring toluene into the obtained container and leaving it to stand for 24 hours.
A foam molded article in which the foam layer was dissolved was evaluated as x.

Room Temperature Impact Resistance Room temperature impact resistance was obtained by cutting a test piece cut from the obtained container.
After standing for 24 hours in a thermo-hygrostat at 23 ° C. and 55% humidity, a spherical weight having a weight of 1 kg was dropped freely in accordance with JIS K7211 to obtain a 50% breaking energy, which was evaluated according to the following criteria. . ：: 50% breaking energy of 1 J or more ×: 50% breaking energy of less than 1 J

Low-Temperature Impact Resistance The low-temperature impact resistance was determined by subjecting a test piece cut from the obtained container to -2.
After leaving in a cool box at 0 ° C for 24 hours, take out, and within 2 seconds after taking out, drop a 1kg spherical weight freely according to JIS K7211 and calculate 50% breaking energy according to the following criteria. Was evaluated. : 50% breaking energy is 0.7 J or more Δ: 50% breaking energy is 0.5 J or more and less than 0.7 J ×: 50% breaking energy is less than 0.5 J

Heat resistance: After leaving in an oven at 95 ° C. for 24 hours, and taking out the product without any visual deformation, the sample was evaluated as having good heat resistance (○).

[0111]

According to the present invention, (1) 20 to 80% by weight of a polystyrene resin is added to the outer surface of the polystyrene resin foam layer;
(2) Polyolefin resin or polyester resin 2
A multi-layer parison having a mixed resin layer composed of a mixture of 0 to 80% by weight (however, the sum of (1) and (2) is 100% by weight) is fused at least in part to the inner surfaces of the parison. By adopting a configuration that can be obtained by molding with a molding die, it is possible to produce a polystyrene-based resin foam molded article without going through a complicated process of injecting a foam after producing a semi-molded article. . Further, according to the present invention, even without using a special adhesive, a layer made of a mixture of a polyolefin resin or a polyester resin and a polystyrene resin can be laminated on the foamed polystyrene resin layer and integrated. So the appearance is beautiful,
A multi-layer polystyrene resin foam molded article excellent in lightness, mechanical strength, heat insulation, cushioning, vibration proof, oil resistance, impact resistance, and the like can be provided. Further, the foamed molded product can be pulverized, melted, collected, and recycled as a raw material for a mixed resin layer or the like.

The multilayer polystyrene resin foam molded article of the present invention comprises a multilayer parison in which a polyolefin resin layer is laminated on the outside of a polystyrene resin foam layer via a mixed resin layer of a fixed composition, and the inside of the parison It includes a configuration in which the surfaces are molded with a mold so that the surfaces are fused at least in part. Therefore, if high-density polyethylene or linear polyethylene is used as the polyolefin-based resin, it is possible to provide a multilayer polystyrene-based resin foam molded article having excellent low-temperature impact resistance in addition to the effects described above. When a high-density polyethylene or a polypropylene resin is used as the polyolefin resin, it is possible to provide a multilayer polystyrene resin foam molded article having excellent heat resistance in addition to the above-mentioned effects.

The multilayer polystyrene resin foam molded article of the present invention comprises a multilayer parison in which a polyester resin layer is laminated on the outside of a polystyrene resin foam layer via a mixed resin layer of a fixed composition, and the inside of the parison is It also includes a configuration in which the surfaces are molded by a mold so that the surfaces are fused at least in part. By adopting such a configuration, it is possible to provide a multilayer polystyrene resin foam molded article having excellent gas barrier properties in addition to the above-described effects.

The multilayer polystyrene resin foam molded article of the present invention is used for lightweight heat insulating panels such as floors and doors, automobile members such as pillars, bumpers, and instrument panels, pallets, containers, desks, chairs, floats, surfboards, and the like. It is particularly suitable as a returnable container.

[Brief description of the drawings]

FIG. 1 (a) is a longitudinal sectional view showing an example of a multilayer polystyrene resin foam molded article of the present invention having a mixed resin layer on the outer surface of a foam layer. FIG. 1B is a vertical cross-sectional view showing an example of the multilayer polystyrene resin foam molded article of the present invention having a polymer layer via a mixed resin layer outside the foam layer.

FIG. 2A is an explanatory diagram of a multilayer parison having a mixed resin layer on the outer surface of a foam layer. FIG. 2B is an explanatory diagram of a multilayer parison having a polymer layer outside a foam layer with a mixed resin layer interposed therebetween.

FIG. 3 is a graph for determining a half-crystallization time of a polyester resin.

FIG. 4 is an explanatory diagram for explaining an example of the method for producing a foam molded article of the present invention.

FIG. 5 is an explanatory diagram for explaining an example of a method for producing a foam molded article of the present invention.

FIG. 6 (a) is an explanatory diagram for explaining an example of a different embodiment of the method for producing a foam molded article of the present invention. FIG.
(B) is explanatory drawing for demonstrating an example of a different aspect of the manufacturing method of the foaming molded article of this invention.

[Explanation of symbols]

 Reference Signs List 1 foamed polystyrene resin foam 2 foamed polystyrene resin 3 mixed resin layer 4 polymer layer 6 multilayer parison

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // B29L 22:00 (72) Inventor Seiji Takahashi 1704-25 Tsuruta-cho, Utsunomiya City, Tochigi Prefecture Terrace House A-102 (72) Inventor Daisuke Imanari 1669 Komakucho, Utsunomiya City, Tochigi Prefecture 201 Wakaba Heights 201 (72) Inventor Taku Kitahama 1126-5 Togamiuemachi, Utsunomiya City, Tochigi Prefecture F term (reference) 4F100 AK03B AK03C AK06 AK12A AK12B AK12H AK41B AK41H AL09B AL09B BA02 BA03 BA07 BA10A BA10C CA30 DD31 DJ01A EC03 GB08 GB16 GB33 GB87 JA04A JA04C JA11C JB04B JB07 JB16H JD02 JH02 JJ02 JK01 JK06 JK10 JK11 JL02 JL03 JL16 YY00 YY00A YY00B YA03A24 AAA AA AA AA AA AA AA AA AA AA AA AA AA AG20 AH26 AH48 AH49 AH56 KA01 KA11 KB26 KK04 KW42

Claims (9)

[Claims] 1. A foam molded article obtained by molding a multi-layer parison having a mixed resin layer on the outer surface of a polystyrene resin foam layer with a molding die such that the inner surfaces of the parison are at least partially fused to each other. Wherein the mixed resin layer comprises (1) 20 to 80% by weight of a polystyrene resin and (2)
Polyolefin resin or polyester resin 20-8
A multilayer polystyrene resin foam molded article comprising a mixture of 0% by weight (however, the total of (1) and (2) is 100% by weight). 2. The multi-layer polystyrene resin foam molded article according to claim 1, wherein the peel strength between the polystyrene resin foam layer and the mixed resin layer constituting the molded article is 100.
(Gf / 25 mm) or more. 3. A polystyrene resin foam layer,
(3) A mixed resin layer composed of a mixture of 20 to 80% by weight of a polystyrene resin and 20 to 80% by weight of a polyolefin resin (the total of (3) and (4) is 100% by weight). A multi-layer polystyrene resin foam molded article obtained by molding a multi-layer parison having a polyolefin resin layer laminated thereon with a mold so that at least a part of the inner surfaces of the parison are fused together. 4. The multilayer polystyrene resin foam according to claim 3, wherein the polyolefin resin layer is made of a polyolefin resin having a Vicat softening point of 112 ° C. or higher. 5. A polystyrene resin foam layer,
(5) A mixture of 20 to 80% by weight of a polystyrene resin and (6) 20 to 80% by weight of a polyester resin (however,
A multilayer parison in which a polyester resin layer is laminated via a mixed resin layer composed of (5) and (6) is 100% by weight) is fused at least partially at the inner surfaces of the parison. Multi-layer polystyrene resin foam molded article obtained by molding with a molding die as described above. 6. The polyester-based resin layer has a half-crystallization time of 3 hours.
The multi-layer polystyrene resin foam molded article according to claim 5, comprising a polyester resin for 0 minutes or more. 7. The foamed multilayer polystyrene resin according to claim 3, wherein the foamed polystyrene resin comprises a foamed polystyrene resin layer, a polyolefin resin layer, or a polyester resin layer. Peel strength of 10
The multilayer polystyrene resin foam molded article according to any one of claims 3 to 6, wherein the thickness is 0 (gf / 25 mm) or more. 8. The multi-layer polystyrene resin foam according to claim 1, wherein the polystyrene resin foam layer is made of a polystyrene resin having a Vicat softening point of 110 ° C. or higher. 9. A phase structure index PI value representing a mixed state of a mixture of a polystyrene-based resin constituting a mixed resin layer and a polyolefin-based resin or a polyester-based resin,
The multilayer polystyrene resin foam molded article according to any one of claims 1 to 8, wherein 0.7 <PI value <1.3.