JP2004074653A - Method for manufacturing foam molded product with skin material and foam molded product with skin material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a foam molded product with a skin material which shows no collapsing of a foamed layer and no appearance of the irregularities of foamed particles on the surface of the skin material and the thorough fusion-bonding of the skin material to the foam molded product with a good appearance and an excellent feel of softness. <P>SOLUTION: This method manufactures the foam molded product with the skin material laminated on the surface by heating the foamed particles of a polyolefin resin packed in a molding space part formed between a first molding die with the skin material arranged on the inner face and a second molding die with many through holes opened in the wall face and fusion-bonding the foamed particles. The skin material is constituted of an olefinic thermoplastic elastomer layer (X), a foamed layer of a crosslinked polypropylene resin (Y) and an olefinic thermoplastic elastomer layer (Z) sequentially laminated. In addition, the olefinic thermoplastic elastomer layer (Z) is arranged so that it is directed to the inner face of the first molding die. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a foam molded article with a skin material and a foam molded article with a skin material.
[0002]
[Prior art]
Conventionally, many proposals have been made for automobile interior materials to which a soft feel is imparted by sticking a skin material to a foamed particle molded article. For example, Japanese Patent Application Laid-Open No. 6-891 discloses a foamed molded article with a skin material on which a skin material composed of a resin sheet and a polyolefin resin extruded foam sheet is attached.
[0003]
However, in the foamed particle molded product with a skin material disclosed in JP-A-6-891, the extruded foamed sheet and the foamed particle molded product constituting the skin material are directly joined, and thus the extruded foamed sheet is heated. Air bubbles are crushed by heating at the time of molding and the flexibility of the skin material is impaired, and the skin material is thinly stretched on the surface of the obtained foamed product with the skin material, particularly at the corners of the foamed molded product with the skin material. In addition, there has been a problem that unevenness of the expanded particles emerges.
[0004]
Also, Japanese Patent Application Laid-Open No. 11-333960 discloses a foam molded article on which a skin material composed of a skin layer, a cushion layer, and a hard sheet layer is stuck.
[0005]
However, the foam molded article with a skin material disclosed in JP-A-11-333960 has a problem that the skin material is easily peeled off. That is, in the foam, foamed particles made of a polyphenylene ether-based resin or a styrene-maleic acid copolymer are used, and heat molding is performed at a low steam pressure so as not to lower the surface appearance of the embossed skin material. In this way, the foamed particles are integrated into the hard sheet layer made of the softened polypropylene-based resin sheet only by penetrating the foamed particles, so that the fusion property between the foamed particles and the hard sheet layer is low.
[0006]
[Problems to be solved by the invention]
In the present invention, the foam layer constituting the skin material is not crushed at the time of heat molding and the flexibility is not impaired, and the skin material is thinly stretched at the corners, so that irregularities of the foamed particles appear on the surface of the skin material. It is an object of the present invention to provide a method for producing a foam molded article with a skin material, which can be fused so that the skin material and the foam molded article are not easily peeled off without impairing the appearance. Another object of the present invention is to provide a foam molded article with a skin material that has a good appearance, has an excellent soft feeling, and does not easily peel off the skin material from the foam molded article.
[0007]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above problems, and as a result, have completed the present invention. That is, according to the present invention, the following invention is provided.
(1) Polyolefin-based resin filled in a molding space formed between a first molding die having a skin material disposed along the inner surface and a second molding die having a large number of through-holes along the wall surface. A method for producing a foam molded article with a skin material having the skin material laminated on a surface thereof by heating and fusing the foamed particles, wherein the skin material comprises an olefin-based thermoplastic elastomer layer (X) and a crosslinked polypropylene-based material. A resin foam layer (Y) and an olefin-based thermoplastic elastomer layer (Z) are sequentially laminated, and the olefin-based thermoplastic elastomer layer (Z) is disposed so as to face the inner surface side of the first mold. A method for producing a foam molded article with a skin material, comprising:
(2) The olefin-based thermoplastic elastomer in a skin material in which an olefin-based thermoplastic elastomer layer (X), a crosslinked polypropylene-based resin foam layer (Y), and an olefin-based thermoplastic elastomer layer (Z) are sequentially laminated. A foam molded article with a skin material, wherein the layer (X) is fused to a foam molded article composed of polyolefin resin foam particles.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the method of the present invention will be described in detail with reference to FIGS.
FIG. 1 is an explanatory view showing a state in which the skin material is arranged on the inner surface of the first molding die. In FIG. 1, 1 is a skin material, 2 is an olefin-based thermoplastic elastomer layer (X) (hereinafter, also simply referred to as “elastomer layer (X)”), and 3 is a cross-linked polypropylene-based resin foam layer (Y) (hereinafter, referred to as “Y”). 4 is an olefin-based thermoplastic elastomer layer (Z) (hereinafter, also simply referred to as an “elastomer layer (Z)”), 31 is a first mold, 10 Indicates the inner surface of the first mold.
FIG. 2 is a schematic diagram illustrating an example of a foam molding apparatus used for carrying out the present invention. In FIG. 2, reference numeral 31 denotes a first molding die, 32 denotes a second molding die, M denotes a molding space portion, N denotes a foamed particle, 11, 11 (2) denotes through holes, 33 denotes a partition plate, 5 is an upper box for molding, 6 is a lower box for molding, 7 is a vacuum suction hole, 8 is a vacuum suction pipe, 9 is an upper box chamber, 12 is a lower box chamber, and 13 is a foamed particle supply pipe. , 13 (2) indicates an air pipe, 14 and 20 indicate heating medium introduction pipes, 16 and 22 indicate cooling water introduction pipes, and 18 and 24 indicate drain discharge pipes, respectively. The first molding die 31 is fixed to the upper molding box 5 and the second molding die 32 is fixed to the lower molding box 6 by bolts (not shown).
[0009]
First, an apparatus used in the method of the present invention will be described. The first molding die 31 shown in FIG. 1 is for forming the external shape of the foam molded body, and the skin material 1 is arranged along the inner surface 10 thereof. At this time, if necessary, the inside of the upper box chamber 9 is depressurized via the vacuum suction pipe 8 and the skin material 1 is sucked through the numerous vacuum suction holes 7 provided along the wall surface of the first mold 31. Thereby, the skin material 1 can be arranged on the inner surface 10 of the first mold 31.
[0010]
The second mold 32 has a large number of through holes 11 along the wall surface. The diameter of the through hole 11 is such that the expanded particles N do not pass therethrough, and is usually about 0.3 to 1 mm, preferably about 0.5 to 0.7 mm.
[0011]
The partition plate 33 divides the lower box chamber 12 located on the back surface of the second mold 32 into two separated spaces, that is, a space A and a space B.
[0012]
It is preferable that the inside of the chamber located on the back surface of the second mold 32 be partitioned into a plurality of separated spaces, but among the above, two separated spaces A and It is more preferable to partition into B.
[0013]
Next, an example of a method for producing a foam molded article with a skin material using the sheet-shaped skin material and the foam molding apparatus shown in FIG. 2 will be described.
First, as shown in FIG. 2, the sheet-like skin material 1 is arranged along the inner surface 10 of the first mold 31. At this time, the upper molding box 5 and the lower molding box 6 are clamped, and heated with steam so that the surface temperature of the first molding die 31 and the second molding die 32 becomes 100 ° C. or higher. The upper box 5 for forming and the lower box 6 for forming are opened to position the sheet between the upper box 5 for forming and the lower box 6 for forming. After heating and softening, the upper mold box 5 and the lower mold box 6 are clamped, and the inside of the upper box chamber 9 is depressurized, so that a large number of pieces penetrated along the wall surface of the first mold 31. The skin material 1 obtained by thermoforming the sheet by suction through the vacuum suction holes 7 is arranged along the inner surface 10 of the first molding die 31.
However, the present invention is not limited to a method using a sheet-like skin material, and for example, a skin material formed by injection molding, stamping molding, or the like can be used. In this case, since the skin material is already formed so as to correspond to the inner surface shape of the mold, it is not necessary to perform the thermoforming as described above, and the skin material 1 is simply formed along the inner surface of the first mold. It should just be arranged.
[0014]
Next, the upper molding box 5 and the lower molding box 6 are opened to the extent that the foamed particles N do not go outside, and the foamed particles N are supplied to the valve (not shown) of the supply pipe 13 and the air pipe 13 (2). (Not shown) to fill the molding space M between the first molding die 31 and the second molding die 32 together with the air flow, and then the valve of the supply pipe 13 and the air pipe 13 (2) Close the valve.
[0015]
The foaming particles N are filled into the molding space M so that the foaming particles N have a predetermined density (predetermined expansion ratio) when molded.
The expanded particles N may be filled by a so-called compression filling method in which the expanded particles N are crushed and filled in a mold.
[0016]
The forming step includes an exhausting step, a heating step, and a cooling step. The exhaust step is a step performed to exhaust air from the molding space M. First, the valve 21 of the heating medium introduction pipe 20 and the valve 19 of the drain discharge pipe 18 communicating with the space B shown in FIG. Then, the other valves, that is, the valve 23, the valve 25, the valve 15, and the valve 17 are closed, and steam is transferred from the space B into the space A through the through hole 11 (2), the molding space M, and the through hole 11. At the same time, air mixed with steam is discharged from the drain discharge pipe 18. Subsequently, the valve 15 of the heating medium introduction pipe 14 and the valve 25 of the drain discharge pipe 24 communicating with the space A shown in FIG. 2 are opened, and the other valves, namely, the valve 17, the valve 19, the valve 21, and the valve With the tube 23 closed, steam is introduced into the space B from the space A through the through hole 11, the molding space M, and the through hole 11 (2), and the air mixed with the steam is discharged from the drain discharge pipe 24. In this way, it is possible to discharge the air between the foamed particles at least twice by changing the flow direction of the steam sequentially to improve the fusion between the foamed particles and the fusion between the foamed particles and the skin material. It is preferable from the viewpoint of doing.
[0017]
Immediately after the evacuation, a heating step is performed. As a method of performing the heating step, steam is introduced into the molding space M from all the through holes 11 and 11 (2) formed in the wall surface of the second molding die 32 so that the steam is introduced into the molding space M. The main heating for heating and fusing the filled expanded particles N, and the through holes 11 or 11 (2) for introducing steam into the molding space M are sequentially changed to introduce steam at least twice. Alternate heating for heating and fusing the foamed particles N filled in the molding space M, a method of combining them, and the like are included. Among these methods, in the case of a foamed molded article having a complicated shape or a thick foamed molded article, it is possible to employ alternating heating in which the through holes for introducing steam are sequentially changed, because the foaming existing in the molding space M This is preferable because the particles N can be efficiently heated and fused to each other, and the expanded particles N and the skin material 1 can be efficiently heated and fused.
[0018]
The heating medium used in the method of the present invention is preferably steam which is excellent in productivity and economy and is industrially advantageous. However, it is also possible to heat with a heating medium in which the temperature is adjusted by mixing compressed air and steam.
[0019]
After the heating step, it is preferable to carry out a cooling step with water, and then take out the foam molded article with a skin material, and if necessary, perform curing and drying at 40 to 80 ° C. for 3 to 24 hours.
[0020]
Next, the skin material used in the present invention will be described.
In the present invention, a skin material in which an elastomer layer (X), a foam layer (Y), and an elastomer layer (Z) are sequentially laminated is used. Such a skin material has excellent sheet elongation during thermoforming, and in particular, the thickness of the corners in the foamed molded article with skin does not become extremely thin, so that the surface of the foamed particle molded article has a foamed molded article with skin. Surface does not protrude unevenly.
[0021]
As the olefin-based thermoplastic elastomer constituting the elastomer layer (X), it is preferable to use an olefin-based thermoplastic elastomer that is particularly suitable for a vehicle application (eg, a bumper grade) from the viewpoint of excellent rigidity, heat resistance, low-temperature brittleness, and printing characteristics. The olefin-based thermoplastic elastomer comprises a blend of a hard segment and a soft segment. Examples of the hard segment include a propylene homopolymer, a propylene-ethylene block copolymer, a propylene-ethylene random copolymer, and a propylene-ethylene butene random copolymer. And the like, or a mixture of two or more of the above-mentioned high melting point resins. The soft segment has the same structure as the resin exemplified as the high melting point resin, but has a melting point of less than 155 ° C., a polypropylene-based resin, a linear ultra low density polyethylene, a branched low density polyethylene, Linear low density polyethylene, medium density polyethylene, polyethylene resin such as high density polyethylene, or polyolefin resin such as polybutene resin, or ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene rubber, ethylene-hexene rubber, ethylene- Synthetic rubbers such as pentene rubber and ethylene-octene rubber are exemplified. The content of these soft segments is up to 50 parts by weight, preferably 40 parts by weight, in the case of polyolefin resin, and 350 parts by weight, preferably 240 parts by weight in the case of synthetic rubber, per 100 parts by weight of the hard segments. Parts as the upper limit. In addition, what is obtained by dynamically heat-treating these blends in the presence of a crosslinking agent as needed may be used.
[0022]
The olefin-based thermoplastic elastomer is preferably one that fuses with the foam particles in that it fuses firmly with the skin material. Further, the melting point of the olefin-based thermoplastic elastomer is preferably the melting point of the polypropylene-based resin constituting the expanded particles described below ± 10 ° C. When the melting point of the olefin-based thermoplastic elastomer is lower than the above range, the foamed molded article may be deformed when the foamed particles are heated and fused to each other. On the other hand, if it is higher than the above range, it becomes difficult to fuse the skin material and the foamed particles, and even if the fusion can be performed by heating at a high temperature, the contraction of the foamed molded article becomes large.
[0023]
Examples of the polypropylene resin constituting the foam layer (Y) of the skin material include propylene homopolymer, propylene-ethylene block copolymer, propylene-ethylene random copolymer, propylene-butene random copolymer, and propylene-ethylene butene random copolymer. And those having one or more selected from the group of propylene-based copolymers containing 70 mol% or more of propylene as a main component.
[0024]
Among the polypropylene resins constituting the foamed layer (Y), those having a melting point of 130 ° C. or more are preferable in that they have excellent heat resistance, and are excellent in heat resistance and also have excellent flexibility and softness. In terms of becoming a skin material, a propylene-ethylene random copolymer, a propylene-butene random copolymer, or a propylene-ethylene-butene random copolymer alone or a mixture of two or more is more preferable.
[0025]
Further, in order to obtain a skin material having a softer feeling, it is preferable to blend another copolymer as a subcomponent with the polypropylene resin constituting the foamed layer (Y). Examples of such auxiliary components include polyolefin-based copolymers, in particular, polyethylene-based resins such as linear ultra-low density polyethylene, branched low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, and high-density polyethylene; -Polyolefin-based elastomers such as propylene rubber, ethylene-butene rubber, ethylene-octene rubber and propylene-butene rubber; and one or more polyolefin-based copolymers selected from polybutene resins.
[0026]
The melting point of the polyolefin-based copolymer blended to enhance the softness of the skin material is preferably less than 140 ° C, more preferably 135 ° C or less, further preferably 130 ° C or less. The lower limit is approximately 100 ° C.
[0027]
Examples of the olefin-based thermoplastic elastomer constituting the elastomer layer (Z) of the skin material include the same olefin-based thermoplastic elastomer constituting the aforementioned elastomer layer (X).
[0028]
The elastomer layer (X), the foam layer (Y), and the elastomer layer (Z) constituting the skin material described above contain various conventional additives such as fillers, stabilizers, reinforcing agents, pigments, and lubricants. You may make it contain. The content is preferably 30 parts by weight or less, more preferably 10 parts by weight or less. The lower limit is approximately 0.01 parts by weight.
[0029]
In the present invention, when the skin material 1 is thermoformed using a sheet, it is necessary that the base resin constituting the elastomer layer (X) and the elastomer layer (Z) be the same, and that the mold and the mold are used when thermoforming. This is preferable because the same shape can be easily formed.
[0030]
In the present invention, as a method of thermoforming a sheet serving as a base material of a skin material, for example, vacuum forming or pressure forming using a mold composed of a male mold and / or a female mold, and free drawing molding as an application thereof, Plug and ridge molding, ridge molding, matched molding, straight molding, drape molding, reverse draw molding, air slip molding, plug assist molding, plug assist reverse draw molding, and molding methods combining these, etc. .
[0031]
The sheet serving as the base of the skin material can be produced by a known method using an extruder. For example, (i) a co-extrusion method such as laminating two or three layers by co-extrusion, and (ii) an elastomer layer (X), a foam layer (Y), and an elastomer layer (Z) in advance using an extruder. A heating lamination method such as separately producing, heat-sealing with a heating roll and laminating, and (iii) forming a foam layer (Y) in advance, and extruding the elastomer layer (X) and the elastomer layer (Z) by extrusion lamination. Extrusion lamination methods such as lamination, and (iv) a lamination method by a combination of the above-mentioned methods.
[0032]
As a method of forming the foamed layer (Y) by an extruder, a thermally decomposable foaming agent and, if necessary, various additives are added to a polypropylene resin as a base resin at a temperature at which the foaming agent is not substantially decomposed. After melt-kneading in an extruder, a foaming sheet is extruded to produce a foamable sheet, and the obtained foamable sheet is cross-linked and then heated to a decomposition temperature of a foaming agent or higher to foam the foam. is there. In addition, you may crosslink after a foaming process.
[0033]
Methods for crosslinking the foamable sheet include electron beam crosslinking, chemical crosslinking with a peroxide, and silane crosslinking using a silane-modified (graft-modified) propylene-based resin. However, in the case of electron beam cross-linking or chemical cross-linking with peroxide, it is necessary to add and knead an additive such as a cross-linking auxiliary agent and / or a peroxide in advance during sheet production. In the crosslinking, at least a part of the propylene-based resin serving as the base material must be silane-modified.
[0034]
As the pyrolytic foaming agent used for crosslinking the foamable sheet, any chemical foaming agent known to be suitable for foaming a polypropylene resin can be used, for example, azodicarbonamide, azo Bisformamide, N, N'-dinitrosopentamethylenetetramine, diazoaminobenzene, benzenesulfonylhydrazide, polypropylene'-oxybisbenzenesulfonylhydrazide, N, N'-dimethyl-N, N'-dinitrosoterephthalamide, etc. Of these, azodicarbonamide is most preferred from the viewpoint of stability and decomposition temperature. These foaming agents may be used alone or in combination of two or more. The amount of the pyrolytic foaming agent used in the present invention is appropriately selected depending on the density of the intended foam, and specifically 0.2 to 30 parts by weight, preferably 100 to 100 parts by weight of the polypropylene resin. It is 0.5 to 20 parts by weight.
[0035]
The foam layer (Y) of the skin material preferably has a gel fraction of 20 to 70% by weight. If the gel fraction exceeds 70%, the fusion with the elastomer layer (X) or the elastomer layer (Z) may be insufficient. On the other hand, if it is less than 20%, since the foamed layer (Y) is in a molten state at the time of heat molding, it is compressed and the thickness is reduced, so that the soft feeling is reduced, and in some cases, the line at the interface between the foamed particles becomes The appearance is impaired due to the transfer to the uneven shape.
[0036]
The gel fraction of the foamed layer (Y) refers to a value indicating the degree to which the foamed layer (Y) is crosslinked. The value of the gel fraction is measured and calculated as follows. First, a sample having a weight of about 1 g is cut out from the foamed layer (Y), the sample is immersed in 200 ml of xylene, heated, and refluxed with xylene boiling at normal pressure for 8 hours. Next, the insolubles were quickly filtered through a wire mesh of 74 μm specified in JIS Z8801 (1966), and then the insolubles were dried under reduced pressure for 24 hours. To the drying under reduced pressure), and finally the weight (g) of the remaining insoluble matter is measured, and calculated by the following equation (1).
[0037]
(Equation 1)
Gel fraction (%) = (weight of insoluble matter / weight of sample used for measurement) × 100 (1)
[0038]
The expansion ratio of the foam layer (Y) constituting the skin material is 5 to 50 times (apparent density 0.018 to 0.184 g / cm). ³ ) Can be manufactured, but in order to give a soft feeling, it is 10 to 45 times (0.020 to 0.092 g / cm in apparent density). ³ ) Is preferable.
[0039]
As described above, the sheet serving as the base of the skin material 1 used in the method of the present invention is formed by sequentially laminating the elastomer layer (X), the foam layer (Y), and the elastomer layer (Z), as described later. Then, the elastomer layer (X) is fused with the foamed molded article composed of the foamed particles. The thickness of the elastomer layer (X) is set so that the foamed particles are not crushed by the foamed particles when filling the foamed particles, particularly at the location of the elastomer layer (X) corresponding to the filling port of the filling machine. In light of this, it is preferably 0.10 mm or more, more preferably 0.20 mm or more, and even more preferably 0.30 mm or more. On the other hand, the upper limit is preferably 1.00 mm or less, more preferably 0.80 mm or less, and even more preferably 0.60 mm or less from the viewpoint of reducing the heating time when thermoforming the skin material. When the thickness of the resin layer (X) is within the above-mentioned specific range, the resin layer (X) is easily melted during heat molding but is not easily broken, and has excellent fusion property with the foamed particles.
[0040]
The thickness of the foam layer (Y) is preferably 1.00 mm or more, more preferably 1.20 mm or more, and further preferably 1.40 mm or more from the viewpoint of obtaining a foamed molded article with a skin material having a high cushioning property and a soft feeling. . On the other hand, the upper limit is preferably 4.00 mm or less, more preferably 3.50 mm or less, and more preferably 3.00 mm or less, from the viewpoint of reducing the heating time when performing heat molding.
[0041]
The thickness of the elastomer layer (Z) is 0.20 mm from the viewpoint that the surface of the mold can be easily transferred to the surface of the foamed article with the skin material and that the surface of the foamed article with the skin material obtained is hardly damaged. The above is preferable, 0.30 mm or more is more preferable, and 0.40 mm or more is further preferable. On the other hand, the upper limit is preferably 1.50 mm or less, more preferably 1.20 mm or less, and still more preferably 1.00 mm or less, from the viewpoint of reducing the heating time when performing heat molding.
[0042]
The thickness of the sheet serving as the base of the skin material 1 used in the method of the present invention is preferably from 1.30 to 6.50 mm, more preferably from 1.50 to 5.50 mm, from the viewpoint of each layer described above. More preferably, it is 1.70 to 5.00 mm.
[0043]
In the method of the present invention, the skin material 1 described above is applied to the inner surface 10 of the first mold 31 so that the elastomer layer (Z) 4 faces the inner surface 10 of the first mold 31 as shown in FIG. Place along. Also, as shown in FIG. 2, the upper molding box 5 and the lower molding box 6 are clamped to form a molding space M. Next, after filling the foamed polypropylene resin particles (hereinafter simply referred to as foamed particles) N into the molding space M, steam is introduced into the molding space M to form the foamed particles N and the foamed particles. The particles N and the skin material 1 are fused.
[0044]
In the method of the present invention, the method of arranging on the inner surface 10 of the first mold 31 is as follows: (a) arranging the skin material 1 previously molded by another mold on the inner surface 10 of the first mold 31; The upper molding box 5 and the lower molding box 6 may be clamped to form a molding space M. (b) The sheet material is heated and softened, and the skin material thermoformed by the first molding die 31 1 may be directly placed on the inner surface 10 of the first molding die 31, and at the same time, the upper molding box 5 and the lower molding box 6 may be clamped to form the molding space M.
[0045]
In the method of the present invention, the method (b) is preferable among the methods described above. According to this method, the thermoforming of the sheet and the forming of the foamed molded article composed of the foamed particles N can be performed by using one mold, so that the skin material 1 is molded by another mold (a). Higher productivity than method.
[0046]
Examples of the polypropylene resin constituting the expanded particles N used in the method of the present invention include propylene homopolymer, propylene-ethylene block copolymer, propylene-ethylene random copolymer, propylene-butene random copolymer, propylene-ethylene-butene random copolymer, and the like. . When the polypropylene resin is a block copolymer, the propylene content is preferably 75 to 97% by weight, and when the polypropylene resin is a random copolymer, the propylene content is preferably 93 to 99.7% by weight. These polypropylene resins preferably have a melting point of 135 ° C. or higher, more preferably 142 ° C. or higher, in order to impart heat resistance and rigidity to the obtained foam molded article with a skin material. The upper limit of the melting point is about 170 ° C.
[0047]
Further, as the polypropylene-based resin constituting the expanded particles N, a polypropylene-based resin having the above-mentioned main component as a main component and another polymer blended as an auxiliary component depending on the purpose may be used. Such subcomponent polymers include polyethylene resins such as linear ultra low density polyethylene, branched low density polyethylene, linear low density polyethylene, medium density polyethylene, and high density polyethylene, ethylene-propylene rubber, ethylene-butene rubber. , An ethylene-octene rubber, an elastomer such as a polyolefin such as propylene-butene rubber, and a polybutene resin. When the total amount of the main component and the subcomponent is 100% by weight, the content of the subcomponent is preferably at most 40% by weight, more preferably at most 30% by weight, and particularly preferably at most 20% by weight.
[0048]
Next, the foamed particles N used in the method of the present invention can be produced, for example, by the following conventionally known method.
First, a polypropylene-based resin is extruded into a strand using an extruder, cooled through water, and cut to obtain resin particles. In this case, the polypropylene resin may contain various conventional additives such as a filler, a stabilizer, a reinforcing agent, a pigment, and a lubricant. Next, the resin particles were impregnated with an inorganic gas-based blowing agent and / or a volatile organic blowing agent while being stirred with water, for example, in a closed pressure-resistant container, and heated to a predetermined foaming temperature under pressure. Later, it can be obtained by a method such as release into a low pressure region.
[0049]
The apparent density of the expanded particles N is 0.015 to 0.450 g / cm. ³ Is preferably 0.030 to 0.300 g / cm. ³ Is more preferred. Apparent density 0.450g / cm ³ When it exceeds, the obtained foamed molded article may lack the lightness characteristic of the foamed article. On the other hand, the apparent density is 0.015 g / cm ³ If it is less than the above, the strength of the obtained foam molded article may be reduced.
[0050]
In addition, the said apparent density is measured as follows.
1000 foamed particle groups were sampled and dried for 24 hours at a temperature of 60 ° C. and a relative humidity of 15%, and then left for 24 hours at a temperature of 23 ° C. and a relative humidity of 50%. Next, the weight of this sample: W (g) was measured, and then the sample was immersed in ethanol at 23 ° C. in a measuring cylinder, and the true volume of the sample: L (cm) ³ ) Was measured and determined by the following equation (2).
[0051]
(Equation 2)
Apparent density (g / cm) ³ ) = W ÷ L (2)
[0052]
The amount of heat at the high-temperature endothermic peak of the expanded particles N used in the method of the present invention is preferably 5 to 60 J / g in order to increase the mechanical strength of the obtained expanded molded article when molding the expanded particles N. A gap is generated between the foamed particles of the molded body, and the gap is not traced on the surface of the skin material and is not transferred, and the mechanical properties of the foamed molded body with the skin, particularly, the compressive strength can be increased. . When the base resin of the expanded particles N is a propylene homopolymer, the calorie at the high temperature peak is preferably 15 J / g or more, more preferably 20 J / g or more from the viewpoint of increasing the compressive strength of the obtained foamed molded article with skin. Is more preferred. On the other hand, from the viewpoint of reducing the effect of lowering the molding temperature, it is preferably at most 60 J / g, more preferably at least 55 J / g. When the base resin of the foamed particles N is a propylene-ethylene random copolymer, the calorie at the high temperature peak is preferably 5 J / g or more from the viewpoint of increasing the compressive strength of the obtained foamed molded article with skin. And more preferably 10 J / g or more. On the other hand, the upper limit is preferably 30 J / g or less, from the viewpoint that gaps are formed between the foamed particles of the obtained foamed molded article with the skin and the gaps are not transferred to the surface of the skin material as traces. / G or less is more preferable.
[0053]
The high-temperature endothermic peak of the expanded particles is the same as that described as “high-temperature peak calorific value” in JP-A-2002-53692, and is described in JP-A-61-4738 and JP-A-8-259724. Is present on the DSC curve due to the presence of “secondary crystals” in the expanded polypropylene resin particles. Therefore, when the secondary crystallization is not performed in the production process of the expanded particles, the obtained expanded particles do not show the endothermic peak on the high-temperature side. Further, even in the case of foamed particles having a high-temperature endothermic peak, for example, when the foamed particles are melted by raising the temperature to a temperature equal to or higher than the melting end temperature of the high-temperature endothermic peak, the secondary crystal disappears. A high-temperature endothermic peak does not appear in the measurement sample. The method of adjusting the amount of heat of fusion at the high-temperature endothermic peak of the expanded particles is as described in the above-mentioned known document. Foamed particles exhibiting a high-temperature endothermic peak tend to have a low reject rate and a high mechanical strength of the resulting foamed molded article in the production of the foamed molded article.
[0054]
In the foam molded article obtained by the method of the present invention, the skin material and the foam molding are formed at the interface between the elastomer layer (X) composed of the olefin resin elastomer constituting the skin material and the foam molded article composed of the polypropylene resin foam particles. Since the body is heated and fused, the skin material does not easily come off the foam molded body. In addition, when the skin material and the foamed particle molded article are heated and fused, the foamed layer (Y) may be crushed because the elastomer layer (X) absorbs the force of secondary expansion of the foamed particles and the pressure of the heating medium. Absent. Therefore, the obtained foam molded article with a skin material has a beautiful appearance because the irregularities of the foamed particles do not appear at the corners of the surface. Moreover, since the skin material is provided with the elastomer layer (X), it is excellent in thermoformability, and the thickness of the skin material of the obtained molded article is small.
[0055]
The shape of the foam molded article with a skin material obtained by the method of the present invention can be made to an arbitrary shape by changing the shape of a molding die.
[0056]
The foam molded article with a skin material of the present invention is a skin material in which an elastomer layer (X), a foam layer (Y), and an elastomer layer (Z) are laminated in this order. It is fused to a foamed molded article composed of particles.
[0057]
The configuration of the elastomer layer (X) of the foam molded article with a skin material of the present invention is the same as the configuration of the elastomer layer (X) in the method of the present invention described above. The structure of the foam layer (Y) of the skin material is the same as the structure of the foam layer (Y) in the method of the present invention described above, and the elastomer layer (Z) of the skin material in the foam molded article with the skin material of the present invention is used. The structure of the skin material in the foam molded article with the skin material of the present invention is the same as the structure of the elastomer layer (Z) in the method of the present invention described above. And the same configuration as the above. In addition, the configuration of the expanded molded article made of the expanded polypropylene resin particles in the expanded molded article with a skin material of the present invention is the same as the configuration of the expanded molded article formed of the expanded polypropylene resin particles of the method of the present invention described above. Can be
[0058]
For the foam molded article with a skin material of the present invention, the above-mentioned method is mentioned as a production example. Therefore, the foam molded article has a good appearance, has an excellent soft feeling, and the skin material is not easily peeled off from the foam molded article.
[0059]
Further, in the foam molded article with a skin material of the present invention, since the skin material 1 is fused to a foam molded article made of foamed polypropylene resin particles, static compression characteristics such as energy absorption and local compression elastic modulus are obtained. In addition, it is excellent in bending characteristics, has a remarkable effect on collision resistance, and can be reduced in weight when applied to a vehicle component, particularly a vehicle bumper. Furthermore, it can be suitably used as interior materials of automobiles such as instrument panels, pillars, and door panels that require high strength, box materials, electronic devices, pallet boards, and the like.
[0060]
【Example】
Next, the present invention will be described in more detail with reference to examples.
[0061]
Example 1
As a sheet serving as a base material of the skin material, the elastomer layer (X) has a thickness of 0.4 mm, the foam layer (Y) has a Tolepef AP67 manufactured by Toray Industries, Inc., an expansion ratio of 20 times, a thickness of 2.5 mm, and an elastomer layer (Z). Was 0.6 mm and the overall thickness was 3.5 mm.
The sheet was subjected to a tensile test. Specifically, JIS K7113 (1981) No. 2 type was manufactured, and the test was performed at a distance between grips of 80 mm, at a speed of 200 mm / min, at 23 ° C., and at a humidity of 50%. The tensile elongation of the skin material was 330% when the tensile stress was 5.1 MPa (G).
[0062]
Using the apparatus shown in FIG. 2, the upper molding box 5 and the lower molding box 6 are clamped, and the first molding die 31 and the first molding die 32 are heated to 100 ° C. or higher. When the lower box 6 for molding is opened and the distance between the upper box 5 for molding and the lower box 6 for molding is set to 160 mm, the sheet serving as the base of the skin material is placed between the first molding die 31 and the second molding die 32. It was installed in. Next, the sheet is heated from the second mold 32 with steam of 0.196 MPa (G) for 3.5 seconds to soften it, and the upper box 5 and the lower box 6 are clamped at the same time as the vacuum suction pipe 8 The upper box chamber 9 located on the back surface of the first molding die 31 was sucked for 7 seconds to form the skin material 1, and the skin material was disposed on the inner surface 10 of the first molding die 31.
[0063]
Next, the molding upper box 5 and the molding lower box 6 were opened, and the distance between the molding upper box 5 and the molding lower box 6 was set to 10 mm, and the foamed particles N were filled.
[0064]
Next, an evacuation step was performed. 2. Steam of 0.980 MPa (G) is introduced into the space A through the valve 15 of the heating medium introduction pipe 14 shown in FIG. 4 for 4 seconds, and the steam is introduced through the wall of the second mold 32 facing the space A from here. The steam is introduced into the molding space M through a large number of through holes 11 formed therein, and steam is circulated in the molding space M to the right in the drawing, and then transmitted through the wall surface of the second molding die 32 facing the space B. The gas was discharged into the space B through a large number of the provided holes 11 (2). At that time, the valves 17, 19, 21 and 23 were kept closed. During this evacuation, the pressure in the space B was 0.049 MPa (G), and the pressure in the space A was 0.196 MPa (G).
[0065]
Subsequently, 0.980 MPa (G) steam is introduced into the space B for 4 seconds through the valve 21 of the heating medium introduction pipe 20, and the steam is introduced through the wall surface of the second mold 32 facing the space B from here. Is introduced into the molding space M through a large number of through holes 11 (2), and steam flows in the molding space M to the left in the drawing, and then the wall surface of the second molding die 32 facing the space A. Was discharged into the space A through a number of through-holes 11 provided in the through hole. At that time, the valves 23, 25, 15 and 17 were closed. During this evacuation, the pressure in the space A was 0.372 MPa (G). The pressure in the space B was 0.196 MPa (G).
[0066]
Next, a heating step including alternating heating and main heating was performed. First, in the alternate heating, steam is introduced into the space A through the valve 15 of the heating medium introduction pipe 14, and a large number of through-holes are provided through the wall of the second mold 32 facing the space A from here. 11 and is introduced into the molding space M through the inside of the molding space M in the right direction in the drawing, and then a large number of through holes 11 are provided through the wall surface of the second molding die 32 facing the space B. It was discharged into the space B through (2). At that time, the valves 21, 23, 25, 17, and 19 were closed. At the time of this heating, the pressure in the space B was set to 0.372 MPa (G).
[0067]
Subsequently, steam is introduced into the space B through the valve 21 of the heating medium introduction pipe 20, and a number of through holes 11 (2) provided through the wall surface of the second mold 32 facing the space B therefrom. ), Into the molding space M, and through the inside of the molding space M, the steam is circulated to the left in the drawing. It was discharged into the space A through the hole 11. At that time, the valves 23, 25, 15, 17, and 19 were closed. At the time of this heating, the pressure in the space A was 0.372 MPa (G).
[0068]
Next, main heating was performed. The steam 15 was introduced into the spaces A and B with the valve 15 of the heating medium introduction pipe 14 and the valve 21 of the heating medium introduction pipe 20 kept open and the other valves closed. During this heating, the pressure in the space A and the space B was set to 0.372 MPa (G).
[0069]
Thereafter, the valves 19 and 25 of the drain discharge pipe were opened, and the pressure in the molding space M was reduced to normal pressure. Next, the valves 23 and 17 of the cooling water introduction pipe were opened, and the other valves were closed to perform water cooling. Subsequently, the valves 19 and 25 of the drain discharge pipe were opened, and the other valves were closed to allow cooling. Thereafter, the upper molding box 5 and the lower molding box 6 are opened to take out a foam molded article with a skin material in which a skin material is integrally laminated and fused on one side, and cured at 60 ° C. under atmospheric pressure for 24 hours. Back to.
[0070]
The obtained foam molded article with the skin material has good fusion property between the skin material and the foam particles, excellent fusion property between the foam particles, and the surface of the foam particles is raised and recessed on the corner surface. It was nothing.
Further, the portion of the skin material corresponding to the filled portion of the foamed particles has no pattern of the trace of filling of the foamed particles because the foamed layer (Y) is not crushed when filled due to the presence of the elastomer layer (X). was gotten.
[0071]
Comparative Example 1
The procedure was performed in the same manner as in Example 1 except that a laminated sheet having a thickness of 3.1 mm except for the elastomer layer (X) was used.
[0072]
The obtained foam molded article with the skin material had good fusion property between the skin material and the foam particles, and excellent fusion property between the foam particles, but the thickness of the skin material was reduced on the surface of the corner portion. As a result, the surface of the foamed particles protruded unevenly on the skin material, and the appearance was poor.
In addition, the surface of the skin material corresponding to the filled portion of the foamed particles had a pattern of traces of filling of the foamed particles.
[0073]
【The invention's effect】
In the foam molded article with a skin material obtained by the method of the present invention, the skin material has three layers, and the interface between the olefin resin elastomer layer (X) constituting the skin material and the foam molded article made of the polypropylene resin foam particles. In the above, since the skin material and the foam molded body are heated and fused, the skin material is not easily peeled off from the foam molded body. In addition, when thermoforming by using a three-layer sheet, the sheet elongation is excellent, and particularly, since the thickness of the corners in the foamed molded article with skin does not become extremely thin, the surface of the foamed particle molded article is There is no embossing on the surface of the foam molded article with skin.
[0074]
In the foam molded article with a skin material of the present invention, the skin material is formed by sequentially laminating an olefin-based thermoplastic elastomer layer (X), a crosslinked polypropylene-based resin foam layer (Y), and an olefin-based thermoplastic elastomer layer (Z). Since the olefin-based thermoplastic elastomer layer (X) and the foamed particle molded article are bonded to each other, the skin material is not easily peeled off from the foamed molded article, and the appearance is beautiful.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a state in which a skin material is arranged on an inner surface of a first molding die.
FIG. 2 is a schematic view of an example of a foam molding apparatus used in an embodiment of the present invention.
[Explanation of symbols]
1 Skin material
2 Elastomer layer (X)
3 Foam layer (Y)
4 Elastomer layer (Z)
31 Inner surface of first mold 31
32 Second mold
M molding space
N expanded particles

Claims (2)

The polyolefin-based resin foam particles filled in the molding space formed between the first molding die in which the skin material is arranged along the inner surface and the second molding die having a large number of through-holes along the wall surface. A method for producing a foam molded article with a skin material having the skin material laminated on the surface by heating and fusing, wherein the skin material is an olefin-based thermoplastic elastomer layer (X) and a cross-linked polypropylene-based resin foam layer (Y) and an olefin-based thermoplastic elastomer layer (Z) are sequentially laminated, and the olefin-based thermoplastic elastomer layer (Z) is arranged so as to face the inner surface side of the first mold. A method for producing a foam molded article with a skin material, which is a feature. The olefin-based thermoplastic elastomer layer (X) in a skin material in which an olefin-based thermoplastic elastomer layer (X), a crosslinked polypropylene-based resin foam layer (Y), and an olefin-based thermoplastic elastomer layer (Z) are sequentially laminated. ) Is fused to a foamed molded article made of polyolefin-based resin foamed particles.

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