JP2010184492A - Heat foaming sheet, foam filling member, and method for filling internal space of hollow member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foam filling member capable of being easily manufactured, and capable of easily filling a protruded space without using a special member even if there is the protruded space in an internal space, a heat foaming sheet used for the foam filling member, and a method for filling the internal space of a hollow member. <P>SOLUTION: The heat foaming sheet 3 is elongated in one direction by foaming when heated at 160°C for 20 min and has 1.8 or higher in the ratio of elongation/contraction magnification before and after foaming in the elongation direction (A) with respect to the elongation/contraction magnification before and after foaming in a direction orthogonal to the elongation direction (A). The heat foaming sheet is formed of a heat foaming composition which contains thermoplastic resin, a foaming agent, a cross-linking agent and a fluorine-containing polymer having fibril forming capability, and has the fluorine-containing polymer compounded at a ratio of 0.1-10 pts.wt. to 100 pts.wt. of the thermoplastic resin. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heating foam sheet, a filled foam member, and a method for filling an internal space of a hollow member.

Conventionally, a hollow member formed as a closed cross section of an automobile pillar or the like is filled with a foam to prevent engine vibration and noise or wind noise from being transmitted to the passenger compartment. It is known.
For example, in general, it is well known to form such a foam by molding a foam material having a specific shape by injection molding or extrusion molding and foaming at 110 to 190 ° C.

However, normally, foamable materials foam uniformly in all directions upon heating. Therefore, if the internal space of the hollow member has a shape such that one side protrudes from the other side with respect to the position where the foamable material is installed, the problem that the protruding space on one side cannot be sufficiently filled. There is.
Therefore, in order to fill the internal space of the hollow member having a protruding space with a foam, for example, a heat-foamed material containing a polymer and a foaming agent is molded by calendering, and 5 to 5 in one direction. Manufacturing a heated foam sheet that stretches at an elongation rate of 50%, and placing the heated foam sheet in the internal space of the hollow member having the protruding space so that the extending direction of the heated foam sheet faces the protruding space. It has been proposed to foam (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2007-76169

If a heat-foamable sheet as described in Patent Document 1 is used, the foam can be filled into the projecting space even when the projecting space is present in the internal space without using a special member.
However, the heat-foamable sheet described in Patent Document 1 needs to be stretched by a plurality of calender rolls at a molding temperature lower than the decomposition temperature of the foaming agent and above the melting point of the polymer, and the manufacturing process is complicated.

  An object of the present invention is to provide a foamed foam member that can be easily manufactured, and can easily fill the protruding space without using a special member, even when there is a protruding space in the internal space. Another object of the present invention is to provide a heating foam sheet used for a filling foam member and a method for filling an internal space of a hollow member.

In order to achieve the above object, the heat-foamable sheet of the present invention is a heat-foamable sheet that expands in one direction when heated at 160 ° C. for 20 minutes, before and after foaming in a direction perpendicular to the direction of elongation. The ratio of the expansion / contraction ratio before and after foaming in the extension direction to the expansion / contraction ratio is 1.8 or more.
The heat-foamable sheet of the present invention is formed from a heat-foamable composition containing the thermoplastic resin, a foaming agent, a crosslinking agent, and a fluorine-containing polymer having fibril molding performance. It is preferable that the fluoropolymer is blended at a ratio of 0.1 to 10 parts by weight with respect to 100 parts by weight of the thermoplastic resin.

Moreover, the filling foam member of this invention is equipped with the above-mentioned heating foam sheet.
In the filled foam member of the present invention, it is preferable that the filling foam member further includes a fixing member that is attached to the heating foam sheet and can be fixed to the internal space of the hollow member.
Further, the filling method of the internal space of the hollow member of the present invention is a filling method of the internal space of the hollow member that fills the internal space of the hollow member by heating and foaming the filling foam member described above, In the internal space of the hollow member, a main space and a protruding space protruding from the main space are formed so as to communicate with each other, and the extending direction of the heating foam sheet is directed toward the protruding space. Thus, it arrange | positions in the said main space, It is characterized by making it foam by heating.

  Moreover, the foam for filling of this invention is obtained by making the above-mentioned heating foam sheet foam.

Since the heat-foamed sheet of the present invention uses a heat-foamed composition in which a specific component for stretching in one direction is selected, any sheet molding can be performed without using a complicated molding method such as calendar molding. It can manufacture by the method and can fill the interior space of the hollow member of the shape which has protrusion space.
The heated foamed sheet of the present invention foams and expands in one direction when heated at 160 ° C. for 20 minutes. Therefore, if this heated foamed sheet is used as a filling foamed member, the main space is formed in the internal space of the hollow member. Even if there is a protruding space protruding from the foamed foam member, if the foamed foam member is placed in the main space so that the expansion direction of the heated foam sheet faces the protruding space and foamed, the protruding space is used as a special member. Even if not, it can be filled easily and at low cost.

The top view of the heating foam sheet which foams, when extending | stretching greatly in an expansion | extension direction when it heats at 160 degreeC for 20 minutes is shown. It is process drawing of one Embodiment of the method of filling the interior space of a pillar using a filling foam member, Comprising: (a) attaches a clip to a heating foam sheet, produces a filling foam member, This is made into a pillar. (B) shows the step of filling the internal space of the pillar with the filling foam by foaming, crosslinking and curing the filling foam member by heating. It is process drawing of the method of filling the interior space of a model pillar using a filling foam member, (a) is a process of installing a filling foam member in a pillar, (b) is a filling foam member by heating, The process of filling the interior space of the model pillar with the foam for filling by foaming and crosslinking is shown. The top view of the filling foam member by which the clip was mounted | worn with the heating foam sheet is shown.

The heat-foamed sheet of the present invention is formed into a sheet form from a heat-foamed composition that is foamed by heating (for example, 150 to 220 ° C.).
The heat-foaming composition comprises a thermoplastic resin as a main component, a foaming agent for foaming the thermoplastic resin, a cross-linking agent for cross-linking and curing the thermoplastic resin, and heating the foamed sheet in one direction. And a fluorine-containing polymer having a fibril molding performance for stretching the film.

  The thermoplastic resin is not particularly limited, and examples thereof include ethylene / vinyl acetate copolymers, olefin resins such as polyethylene and polypropylene, and vinyl resins such as polyvinyl butyral and polyvinyl chloride. Preferably, an olefin resin, more preferably an ethylene / vinyl acetate copolymer is used. By using an ethylene / vinyl acetate copolymer, the expansion ratio can be increased. Of these thermoplastic resins, those having a melting point of 60 to 120 ° C., more preferably 80 to 100 ° C., are preferably selected. If the melting point is less than 60 ° C., the thermoplastic resin may exhibit stickiness and may be difficult to handle even at room temperature. If it exceeds 120 ° C., it is necessary to increase the processing temperature. There is a risk of disassembly. The melting point is determined by DSC (differential scanning calorimeter).

One or more of these thermoplastic resins can be appropriately selected and used.
Examples of the foaming agent include inorganic foaming agents and organic foaming agents. Examples of the inorganic foaming agent include ammonium carbonate, ammonium hydrogen carbonate, sodium hydrogen carbonate, ammonium nitrite, sodium borohydride, azides and the like.
Examples of the organic foaming agent include azo compounds such as azodicarbonamide, barium azodicarboxylate, azobisisobutyronitrile, azodicarboxylic acid amide, such as N, N′-dinitrosopentamethylenetetramine. , N, N′-dimethyl-N, N′-dinitrosotephthalamide, trinitrotrimethyltriamine, and other nitroso compounds such as 4,4′-oxybis (benzenesulfonylhydrazide), paratoluenesulfonylhydrazide, diphenylsulfone- Hydrazide compounds such as 3,3′-disulfonylhydrazide and allylbis (sulfonylhydrazide), for example, semicarbazide compounds such as p-toluylenesulfonyl semicarbazide and 4,4′-oxybis (benzenesulfonyl semicarbazide), for example Trichloromonofluoromethane, fluoride alkanes such dichloro monofluoromethane, for example, triazole compounds such as 5-morpholyl-1,2,3,4-thiatriazole and the like.

Among these foaming agents, those that decompose and generate a gas above the melting point of the thermoplastic resin and hardly foam when the heated foaming composition described later is formed are appropriately selected depending on the composition. The Preferably, those which foam (decompose) at 140 to 200 ° C. are used. More specifically, azodicarbonamide is used.
These foaming agents can be used by appropriately selecting one kind or two or more kinds. The blending ratio of the foaming agent is not particularly limited, but is, for example, 5 to 50 parts by weight, preferably 10 to 30 parts by weight with respect to 100 parts by weight of the thermoplastic resin.

  In addition, the blending amount of the foaming agent may be a range in which the expansion ratio is about 5 to 40 times, preferably about 10 to 35 times, and substantially closed cells are generated when the heated foam sheet is foamed. Is preferred. If the blending amount of the foaming agent is too small, the heat-foamed sheet will not foam sufficiently, while if the blending amount of the foaming agent is too large, voids will be generated due to the resin foam of the filling foam obtained by foaming. Fillability falls.

  The crosslinking agent is not particularly limited, and examples thereof include a radical generator that decomposes by heating to generate free radicals to form crosslinks between molecules or within molecules. More specifically, for example, dicumyl peroxide, 1,1-ditertiarybutylperoxy-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-ditertiarybutylperoxyhexane, 2 , 5-dimethyl-2,5-ditertiarybutylperoxyhexyne, 1,3-bis (t-butylperoxyisopropyl) benzene, tertiarybutylperoxyketone, tertiarybutylperoxybenzoate, etc. Such as things.

Further, when the thermoplastic resin can be vulcanized, a vulcanizing agent can be used as a crosslinking agent. Such a vulcanizing agent is not particularly limited. For example, sulfur, sulfur compounds, selenium, magnesium oxide, lead monoxide, zinc oxide, polyamines, oximes, nitroso compounds, resins, ammonium salts, etc. Is mentioned.
As a crosslinking agent, Preferably, an organic peroxide is mentioned.

These crosslinking agents can be used by appropriately selecting one kind or two or more kinds. Moreover, the mixing ratio of the crosslinking agent is not particularly limited, but is, for example, 0.1 to 10 parts by weight, preferably 0.5 to 7 parts by weight with respect to 100 parts by weight of the thermoplastic resin.
When a vulcanizing agent is used, a vulcanization accelerator can be used in combination. Examples of the vulcanization accelerator include vulcanization accelerators such as dithiocarbamic acids, thiazoles, guanidines, sulfenamides, thiurams, xanthogenic acids, aldehyde ammonias, aldehyde amines and thioureas. Such a vulcanization accelerator can be used by appropriately selecting one or more kinds, and the blending ratio is 0.1 to 5 parts by weight with respect to 100 parts by weight of the thermoplastic resin.

In contrast to the vulcanization accelerator, for the purpose of adjusting moldability, for example, a known vulcanization retarder such as an organic acid or an amine can be appropriately blended.
Examples of the fluorine-containing polymer having fibril molding performance include polytetrafluoroethylene, fluorinated ethylene / polypropylene copolymer, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene / ethylene copolymer, Examples thereof include polychlorotrifluoroethylene and polyvinylidene fluoride. Preferably, polytetrafluoroethylene is used.

Polytetrafluoroethylene having fibril-forming performance (hereinafter abbreviated as fibril PTFE) shows a tendency to be bonded to each other by an external action such as shearing force to form a fiber.
Examples of the fibril PTFE include solid fibril PTFE, aqueous emulsion or dispersion fibril PTFE (hereinafter abbreviated as aqueous fibril PTFE).

  As the solid form fibril PTFE, for example, a powder obtained by coagulation and drying a latex obtained by emulsion polymerization of tetrafluoroethylene (that is, a fine powder of polytetrafluoroethylene, which is type 3 in the ASTM standard). And the like). As the aqueous fibril PTFE, for example, an aqueous dispersion obtained by adding a surfactant to a latex obtained by emulsion polymerization of tetrafluoroethylene, and concentrating and stabilizing (that is, a dispersion of polytetrafluoroethylene). Etc.

The fibril PTFE is preferably a solid fibril PTFE. When aqueous fibril PTFE is used, the heat-and-moisture resistance may decrease due to the dispersant component.
The molecular weight of the fibril PTFE is, for example, 1,000,000 to 10,000,000, preferably 20000 to 90000000, in the number average molecular weight determined from the standard specific gravity.

Moreover, the primary particle diameter of fibril PTFE is 0.05-1.0 micrometer, for example, Preferably, it is 0.1-0.5 micrometer.
Moreover, when using the said polytetrafluoroethylene fine powder as fibril PTFE, the secondary particle diameter is 1-1000 micrometers, for example, Preferably, it is 10-500 micrometers.

  Fibril PTFE is available as a commercial product. For example, Teflon 6J (Mitsui / DuPont Fluoro Chemical), Teflon 30J (Mitsui / DuPont Fluoro Chemical), Polyflon MPA FA-500 (Daikin Chemical Industries) Manufactured), polyflon F-201 (manufactured by Daikin Chemical Industries, Ltd.), polyflon D-1 (manufactured by Daikin Chemical Industries, Ltd.), CD076 (manufactured by Asahi IC Fluoropolymers Co., Ltd.), and the like.

When the fine powder of polytetrafluoroethylene is used as the fibril PTFE, the fibril PTFE can be surface-treated in order to prevent secondary aggregation in the fine powder.
Examples of the surface treatment include calcination of the surface of fibril PTFE (hereinafter abbreviated as “surface calcination treatment”), and coating of the surface of fibril PTFE with polytetrafluoroethylene having non-fibril forming performance (hereinafter abbreviated as “surface coating treatment”). Etc.).

The surface treatment is preferably a surface coating treatment. In the surface baking treatment, the fibril formation performance of polytetrafluoroethylene may be lowered.
In the surface coating treatment, fibril PTFE is blended at a ratio of, for example, 70 to 95 parts by weight with respect to 100 parts by weight of the total amount of polytetrafluoroethylene and fibril PTFE having non-fibril forming performance.

In the surface coating treatment, the molecular weight of the polytetrafluoroethylene having non-fibril forming performance is, for example, 10,000 to 1,000,000, preferably 10,000 to 800,000 in the number average molecular weight determined from the standard specific gravity.
As the fibril PTFE, for example, a mixture of fibril PTFE and other resin (for example, a mixture of fibril PTFE and acrylic resin (hereinafter abbreviated as acrylic-modified fibril PTFE)) can be used. .

  Specifically, as a mixture of fibril PTFE and other resins, for example, an agglomerated mixture (hereinafter simply referred to as an agglomerated mixture) of an emulsion of fibril PTFE and an emulsion of a vinyl polymer is used. . By using the agglomerated mixture, the dispersibility in the thermoplastic resin can be improved, and further better appearance and mechanical properties can be obtained.

  Examples of vinyl polymers include polypropylene, polyethylene, polystyrene, high impact polystyrene resin (HIPS resin), acrylonitrile / styrene copolymer (AS resin), acrylonitrile / butadiene / styrene copolymer (ABS resin), and methyl methacrylate.・ Butadiene / styrene copolymer (MBS resin), methyl methacrylate / acrylonitrile / butadiene / styrene copolymer (MABS resin), acrylonitrile / acrylate / styrene copolymer (AAS resin), polymethyl (meth) acrylate, styrene and butadiene Block copolymer consisting of and a hydrogenated copolymer thereof, block copolymer consisting of styrene and isoprene, and a hydrogenated copolymer thereof, acrylonitrile-butadiene copolymer, Random-propylene random and block copolymers, ethylene-butene random and block copolymers, ethylene / α-olefin copolymers, ethylene / unsaturated carboxylic acid ester copolymers (for example, Ethylene-butyl acrylate), acrylic ester-butadiene copolymers (for example, butyl acrylate-butadiene), rubbery polymers (for example, polyalkyl (meth) acrylate), polyorganosiloxane and polyalkyl (meth) Examples include composite rubbers containing acrylates, and copolymers obtained by graft polymerization of vinyl monomers (for example, styrene, acrylonitrile, polyalkyl methacrylate, etc.) on such composite rubbers.

In the production of the agglomerated mixture, for example, first, an aqueous emulsion of a vinyl polymer and an aqueous emulsion of fibril PTFE are mixed.
An aqueous emulsion of a vinyl polymer can be obtained by a known method for producing an emulsion.
The average particle diameter of the vinyl polymer in the aqueous emulsion of the vinyl polymer is, for example, 0.01 to 1 μm, preferably 0.05 to 0.5 μm, and the solid content concentration is, for example, 25 to 60. % By weight, preferably 30 to 45% by weight.

An aqueous emulsion of fibril PTFE can be obtained, for example, by subjecting tetrafluoroethylene to emulsion polymerization using a fluorine-containing surfactant.
In the aqueous emulsion of fibril PTFE, the average particle diameter of fibril PTFE is, for example, 0.05 to 10 μm, preferably 0.05 to 1.0 μm, and the solid content concentration is, for example, 40 to 70% by weight, preferably Is 50 to 65% by weight.

In the emulsion polymerization, tetrafluoroethylene and other copolymer components (for example, hexafluoropropylene) can be copolymerized. In such a case, the other copolymer components are blended in the resulting copolymer so as to have a ratio of, for example, 10 parts by weight or less with respect to 100 parts by weight of the total amount of the copolymer. .
The aqueous emulsion of vinyl polymer and the aqueous emulsion of fibril PTFE are, for example, 1 to 80 parts by weight, preferably 1 part by weight of fibril PTFE with respect to 100 parts by weight of the total amount of vinyl polymer and fibril PTFE. It mix | blends so that it may become ~ 60 weight part.

  Next, in this method, for example, an aqueous solution in which a metal salt such as calcium chloride or magnesium sulfate is dissolved is heated, and a mixed solution of an aqueous emulsion of a vinyl polymer and an aqueous emulsion of fibril PTFE is then added to the aqueous solution. The vinyl polymer and fibril PTFE are salted out and solidified. Thereby, the aggregated mixture can be separated and recovered.

For example, the aggregated mixture can be separated and recovered by drying a mixed solution of an aqueous emulsion of a vinyl polymer and an aqueous emulsion of fibril PTFE by a method such as spray drying or freeze drying.
As the form of the agglomerated mixture, for example, a form in which the vinyl polymer is surrounded around the fibril PTFE particles, a form in which the fibril PTFE is surrounded around the vinyl polymer, and several particles per one particle. Agglomerated forms are exemplified.

Further, as the agglomerated mixture, for example, a polymer obtained by graft-polymerizing the same or different vinyl polymer as the vinyl polymer in the vinyl polymer emulsion in the outer layer of the agglomerated mixture can also be used.
Examples of such vinyl monomers include styrene, α-methylstyrene, methyl methacrylate, cyclohexyl acrylate, dodecyl methacrylate, dodecyl acrylate, acrylonitrile, and 2-ethylhexyl acrylate. . These vinyl monomers can be used by appropriately selecting one kind or two or more kinds (copolymerization).

  An agglomerated mixture of an emulsion of polytetrafluoroethylene having a fibril-forming performance and an emulsion of a vinyl polymer is also available as a commercial product. For example, Methbrene A-3000 (acrylic fibril PTFE, manufactured by Mitsubishi Rayon Co., Ltd.) ), Methabrene A-3700 (acrylic modified fibril PTFE, manufactured by Mitsubishi Rayon Co., Ltd.), methabrene A-3800 (acrylic modified fibril PTFE (having a molecular weight larger than that of methabrene A-3000) manufactured by Mitsubishi Rayon Co., Ltd.), BLENDEX449 (GE Specialties). Tea Chemicals) is used.

These fluorine-containing polymers having fibril molding performance can be used by appropriately selecting one kind or two or more kinds. Further, the blending ratio of the fluoropolymer having fibril molding performance is, for example, 0.05 to 15 parts by weight, preferably 0.08 to 12 parts by weight, more preferably, relative to 100 parts by weight of the thermoplastic resin. 0.1 to 10 parts by weight.
When the blending ratio of the fluorinated polymer having fibril molding performance is less than 0.05 parts by weight with respect to 100 parts by weight of the thermoplastic resin, it is difficult to stretch the heated foam sheet in one direction by heating. There is a case. Moreover, when exceeding 15 weight part, it may become difficult to extend | stretch a heating foam sheet to one direction by heating, and also there exists a malfunction that cost starts.

Moreover, in order to foam a thermoplastic resin efficiently, for example, a foaming assistant is further mix | blended with a heat | fever foaming composition suitably.
Although it does not restrict | limit especially as a foaming adjuvant, For example, according to the kind of foaming agent, a well-known foaming adjuvant can be selected suitably, For example, the urea type compound which has urea as a main component, for example Examples thereof include metal oxides such as zinc oxide and lead oxide, higher fatty acids such as salicylic acid and stearic acid, and metal salts thereof (for example, zinc stearate) and the like. Preferably, metal oxides and metal salts of higher fatty acids are used.

These foaming auxiliaries can be used by appropriately selecting one kind or two or more kinds. The blending ratio of the foaming aid is not particularly limited, but is, for example, 1 to 20 parts by weight, preferably 5 to 10 parts by weight with respect to 100 parts by weight of the thermoplastic resin.
Furthermore, the heat-foaming composition includes, for example, a stabilizer, a reinforcing material, a filler, a softening agent, a lubricant, and the like within a range that does not affect the physical properties of the obtained foam for filling, depending on the purpose and application. If necessary, for example, known additives such as a plasticizer, an antioxidant, an antioxidant, a pigment, a colorant, an antifungal agent, and a flame retardant can be appropriately blended.

The heated foam composition is prepared, for example, by blending the above-described components at the blending ratio described above, and then kneading using, for example, a mixing roll or a pressure kneader.
The viscosity of the heat-foaming composition is preferably adjusted to 100 to 10,000 Pa · s (120 ° C.).
The heat-foamable sheet is formed by continuously forming the heat-foamable composition prepared as described above into a sheet using, for example, a press, a mixing roll, a calender roll, or the like, or the heat-foamable composition is extruded, for example. It can be obtained by continuous molding into a sheet using a machine.

The thickness of the heat-foamed sheet is set to 1 to 20 mm, preferably 1.5 to 10 mm, for example.
In addition, a heat-foamable sheet can also be coated on a well-known base material sheet etc., and can also be obtained as a lamination sheet.
And when a heat-foaming composition is rolled, for example with a mixing roll etc., the fluorine-containing polymer which has a fibril molding performance is orientated in a flow direction inside a heat-foaming sheet.

Therefore, in the heat-foamed sheet thus obtained, foaming in the orientation direction (flow direction) of the fluoropolymer having fibril molding performance is suppressed, and the direction orthogonal to the orientation direction of the fluoropolymer having fibril molding performance Foaming is promoted.
As a result, the heat-foamed sheet thus obtained was heated at, for example, a temperature equal to or higher than the melting point of the thermoplastic resin, more specifically, 160 ° C. for 20 minutes, as shown in FIG. In some cases, it may be referred to as one direction, that is, a direction (hereinafter referred to as “extension direction A”) orthogonal to the orientation direction of the fluoropolymer having fibril molding performance (hereinafter also referred to as “orthogonal direction B”). ) Foams while stretching.

In the heated foam sheet, the expansion ratio before and after foaming in the extension direction A (hereinafter referred to as expansion / contraction) with respect to the expansion / contraction ratio before and after expansion (hereinafter referred to as expansion / contraction ratio B) in the direction orthogonal to the extension direction A (that is, the orthogonal direction B) The ratio (hereinafter referred to as the foam aspect ratio) is, for example, 1.8 or more, and preferably 2.5 or more from the viewpoint of filling properties.
The expansion ratio A and the expansion ratio B are the following formulas (1) and (2) when the heated foam sheet is cut into a test piece and heated at 160 ° C. for 20 minutes as shown in FIG. Is calculated by In general, the expansion / contraction magnification is evaluated by cutting a test piece from a sheet having a thickness of 3 mm into a square shape of 25 (mm) × 25 (mm).

Expansion / contraction magnification A (%) = {L2A (mm) / L1A (mm)} × 100 (1)
L2A (mm): Length of heated foam sheet after heating in extension direction A (mm)
L1A (mm): Length of the heated foam sheet before heating in the extension direction A (mm)
Expansion / contraction magnification B (%) = {L2B (mm) / L1B (mm)} × 100 (2)
L2B (mm): Length of heated foam sheet after heating in orthogonal direction B (mm)
L1B (mm): Length of heated foam sheet before heating in orthogonal direction B (mm)
The foam aspect ratio is calculated by the following equation (3).

Foam aspect ratio = Expansion / contraction ratio A (%) / Expansion / contraction ratio B (%) (3)
When the foam aspect ratio is less than 1.8, the effect of improving the filling property is lowered.
And the foam for filling of this invention can be formed by heating and foaming and hardening the heating foam sheet of this invention.
The filling foam of the present invention has a density (foam weight (g) / foam volume (g / cm ³ )) of, for example, 0.04 to 0.2 g / cm ³ , preferably 0.05 to 0.1 g / cm ³ , and the expansion ratio at the time of foaming is, for example, 5 to 40 times, preferably 10 to 35 times.

The foam for filling of the present invention obtained in this way is not particularly limited, and is used for vibration suppression, soundproofing, dustproofing, heat insulation, buffering, watertightness, etc., between various members and the internal space of the hollow member. For example, it can be suitably used as a filler for various industrial products such as a vibration-proof material, a sound-proof material, a dust-proof material, a heat-insulating material, a shock-absorbing material, and a water-stop material.
And in such a heat-foamable sheet and a foam for filling, the space to be filled is formed by foaming of the heat-foamable sheet even if the internal space of the hollow member has a protruding space protruding from the main space. The filling foam can fill the space with almost no gap.

FIG. 2 shows a process diagram of an embodiment of a method for filling an interior space of a pillar using a filling foam member.
Next, a method of filling the internal space of the pillar by heating and foaming the obtained foamed member including the heated foam sheet will be described with reference to FIG.
As shown in FIG. 2, the filling foam member 4 includes a heating foam sheet 3 and a clip 5 as a fixing member that is attached to the heating foam sheet 3 and can be fixed to the internal space 7 of the pillar 6 as a hollow member. I have.

The clip 5 is made of a hard resin and is integrally formed by injection molding or the like. The clip-shaped fixing portion 24 for fixing the heating foam sheet 3 to the internal space 7 and the fixing portion 24 are attached to the pillar 6. And a bowl-shaped mounting portion 25 are integrally provided.
The filled foam member 4 is produced by fitting the fixing portion 24 of the clip 5 into the heated foam sheet 3 cut into an appropriate shape by punching or the like corresponding to the hollow space 7 of the hollow member 6. .

The pillar 6 includes an inner panel 16 and an outer panel 17.
The inner panel 16 is integrally provided with an inner concave portion 18 that is recessed downward and has a substantially concave shape in a front sectional view, a right flange portion 31, and a left flange portion 32.
The outer panel 17 is vertically opposed to the right end portion and the center portion of the inner recess portion 18 of the inner panel 16 and bulges upward to form a substantially concave shape in front sectional view, and the left end portion of the outer recess portion 19. , A flat plate portion 20 having a flat plate shape, a right flange portion 33, and a left flange portion 34, which continuously extend toward the left side. The right flange portion 31 of the inner panel 16 and the right flange portion 33 of the outer panel 17 are opposed to each other and joined by welding, and the left flange portion 32 of the inner panel 16 and the left flange portion 34 of the outer panel 17 are joined together. They are brought into contact with each other and joined by welding. Thereby, the hollow space 7 of the pillar 6 is formed as a closed cross section. More specifically, such a pillar 6 is used as a front pillar, a side pillar, or a rear pillar of a vehicle body of an automobile.

The hollow space 7 is formed from a main space 8 formed by the inner concave portion 18 and the right side portion and the central portion of the outer concave portion 19, and a protruding space 9 formed by the flat plate portion 19 and the outer concave portion 19. . More specifically, a main space 8 and a protruding space 9 protruding from the main space 8 toward the left side are formed in the internal space 7 of the pillar 6 so as to communicate with each other.
In this method, first, as shown in FIG. 2A, in the internal space 7 of the pillar 6, the filling foam member 4 is placed in the main direction so that the extending direction A of the heated foam sheet 3 is directed to the protruding space 9. Arrange in space 8.

  In order to arrange the filling foam member 4 in the main space 8, first, the expansion direction A of the heating foam sheet 3 is placed in the opposing direction of the right flange portion 31 and the left flange portion 32 of the inner panel 16. The clip 5 is fixed to the inner panel 16 while the mounting portion 25 of the clip 5 is locked in the mounting hole 35 of the inner panel 16 while being arranged along the line. Thereby, the filling foam member 4 is fixed to the position of the inner concave portion 18 facing the outer concave portion 19, that is, the right portion and the central portion of the inner concave portion 18.

  Next, the right flange portion 31 of the inner panel 16 and the right flange portion 33 of the outer panel 17 and the left flange portion 32 of the inner panel 16 and the left flange portion 34 of the outer panel 17 are brought into contact with each other and joined by welding. Thus, the internal space 7 including the main space 8 and the protruding space 9 is formed. Thereby, the filling foam member 4 can be arrange | positioned in the main space 8 so that the expansion | extension direction A of the heating foam sheet 3 goes to the protrusion space 9. FIG.

  And in this method, after giving an antirust process to the inner peripheral surface of the pillar 6 after that, it heat-foams by the heating (for example, 110-190 degreeC) in the drying line process at the time of subsequent baking coating, for example. By foaming, crosslinking and curing the sheet 3, a filling foam 10 is formed as shown in FIG. 2 (b), and the internal space 7 of the pillar 6 is filled with the filling foam 10 without a gap.

  That is, in the filling method of the hollow space 7 of the pillar 6, the heated foamed sheet 3 extends in the extending direction A by heating, so that even if the protruding space 9 is present in the internal space 7 of the pillar 6, If it arrange | positions in the main space 8 so that the expansion | extension direction A of the heating foam sheet 3 may go to the protrusion space 9, the protrusion space 9 is filled easily and low-cost without a gap, without using a special member. Can do.

Moreover, since the heat-foamed sheet 3 is formed from a heat-foamed composition containing a fluorine-containing polymer having a fibril-molding performance for extending in one direction, it is optional regardless of a complicated molding method such as calendar molding. The hollow space 7 of the pillar 6 having the protruding space 9 can be filled.
Further, in the above description, the filling foam member 4 includes the heating foam sheet 3 and the clip 5, but the filling foam member 4 of the present invention is not limited to this, for example, the clip 5 is not attached. Alternatively, it may be formed only from the heated foam sheet 3.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the examples and comparative examples.
(Preparation of heated foam sheet)
Example 1
100 parts by weight of ethylene / vinyl acetate copolymer (Evaflex EV460, melting point 84 ° C., MFR 2.5, vinyl acetate content 19%, manufactured by Mitsui DuPont Polychemical Co., Ltd.) as a thermoplastic resin using a pressure kneader, The mixture was kneaded at 130 ° C. for 5 minutes at a rotation speed of 20 min ⁻¹ .

  Next, 20 parts by weight of azodicarbonamide (Vinole AC # 1C, decomposition temperature 199 ° C., manufactured by Eiwa Kasei Kogyo Co., Ltd.) as a foaming agent, and zinc oxide (Zinc oxide type II, manufactured by Mitsui Mining Co., Ltd.) as a foaming aid Parts, zinc stearate (SZ-P, manufactured by Sakai Chemical Industry Co., Ltd.), dicumyl peroxide (park mill D-40MBK, dicumyl peroxide content 40%, silica and EPDM content 60%, Nippon Oil & Fats) 5 parts by weight, as a fluorine-containing polymer having fibril molding performance, 2 parts by weight of acrylic-modified fibril PTFE (methabrene A-3000, manufactured by Mitsubishi Rayon Co., Ltd.) is blended, and further kneaded at 130 ° C. for 4 minutes. A heated foam composition was prepared.

Next, a heated foam sheet having a thickness of about 3 mm was formed by rolling with a mixing roll having a rotational speed of 20 min ⁻¹ .
Examples 2 to 6 and Comparative Example 1
Except that each component was blended according to the blending formulation shown in Table 1, heat-foamed sheets of the respective examples and comparative examples were molded in the same manner as in Example 1.

The abbreviations and product names in Table 1 are as follows. The formulations in Table 1 are shown in parts by weight.
EVA460: EVAFLEX EV460, melting point 84 ° C., MFR 2.5, vinyl acetate content 19%, manufactured by Mitsui DuPont Polychemical Co., Ltd. AC # 1C: azodicarbonamide, decomposition temperature 199 ° C., manufactured by Eiwa Chemical Industry Co., Ltd., zinc oxide type II: Zinc oxide, manufactured by Mitsui Kinzoku Mining Co., Ltd. SZ-P: zinc stearate, manufactured by Sakai Chemical Industry Co., Ltd. D-40MBK: Park mill D-40MBK, dicumyl peroxide content 40%, silica and EPDM content 60%, manufactured by NOF Corporation A -3000: methabrene A-3000, acrylic modified fibril PTFE, manufactured by Mitsubishi Rayon Co., Ltd. A-3800: methabrene A-3800, acrylic modified fibril PTFE, manufactured by Mitsubishi Rayon Co., Ltd. F-201: polyflon F-201, fibril PTFE, Daikin Chemical Industries Made by company (evaluation of heated foam sheet)
(Foaming aspect ratio)
As shown in FIG. 1, the obtained heat-foamed sheet was cut into a 25 mm × 25 mm square to obtain a test piece. This test piece was heated at 160 ° C. for 20 minutes, the elongation ratio in the stretching direction A and the orthogonal direction B was calculated, and the foaming aspect ratio was calculated. The results are shown in Table 1. When heated at the above-described temperature, the heated foamed sheet expanded while greatly extending in the extending direction A with respect to the orthogonal direction B.
(Foaming ratio)
From the obtained heat-foamed sheet, a 30 mm × 30 mm square was cut out to obtain a test piece. This test piece was heated at 160 ° C. for 20 minutes, and the expansion ratio was calculated by the following formula (4). The results are shown in Table 1.

Foaming ratio = (density before foaming) / (density after foaming) (4)
(Production of filled foam member)
As shown in FIG. 4, the obtained heat-foamed sheet was cut into a rectangular shape of 15 mm × 75 mm, and then a test piece was obtained by forming a clip hole (φ5 mm) at the right end thereof. A fixed portion (φ5 mm) of a clip made of 6,6-nylon was attached to the clip hole of this test piece to produce a filled foam member.
(Evaluation of filled foam member)
(Foam filling property)
First, as shown in FIG. 3A, a model pillar having a main space of 10 mm × 70 mm and a protruding space of 7 mm × 20 mm as a closed cross section was produced.

Next, the mounting portion of the clip is fixed to the inner pillar so that the expansion direction of the heated foam sheet is along the opposing direction of the right and left ends of the inner panel of the model pillar. Therefore, it was placed in the main space. In addition, the filling foam member was arrange | positioned so that the left side edge part of a heating foam sheet may face a protrusion space slightly.
Next, as shown in FIG. 3B, the model pillar on which the filled foam member was arranged was heated in an oven at 160 ° C. for 20 minutes to foam the heated foam sheet. Subsequently, after cooling, the model pillar was disassembled, and the filling property of the filling foam was visually evaluated. The results are shown in Table 1. In Table 1, “◯” indicates that the filling property was good, and “x” indicates that there was a gap and the filling property was slightly poor.

3 Heating foam sheet 4 Filling foam member 5 Clip 6 Pillar 7 Inner space 8 Main space 9 Protruding space 10 Filling foam

Claims (6)

A heated foam sheet that expands in one direction when it is heated at 160 ° C. for 20 minutes,
The ratio of the expansion / contraction ratio before and after foaming in the extension direction to the expansion / contraction ratio before and after foaming in a direction orthogonal to the extension direction is 1.8 or more. The heat-foamed sheet is formed from a heat-foamed composition containing a thermoplastic resin, a foaming agent, a crosslinking agent, and a fluorine-containing polymer having fibril molding performance,
The heat-foamable sheet according to claim 1, wherein the fluoropolymer is blended at a ratio of 0.1 to 10 parts by weight with respect to 100 parts by weight of the thermoplastic resin.   A filled foam member comprising the heated foam sheet according to claim 1.   The filling foam member according to claim 3, further comprising a fixing member attached to the heating foam sheet and capable of being fixed to an internal space of the hollow member. A method for filling an internal space of a hollow member, wherein the internal space of the hollow member is filled by heating and foaming the filled foam member according to claim 3 or 4,
In the internal space of the hollow member, a main space and a protruding space protruding from the main space are formed so as to communicate with each other,
A filling method of an internal space of a hollow member, wherein the filling foam member is disposed in the main space so that an extending direction of the heating foam sheet is directed to the protruding space, and foamed by heating.   A foam for filling, which is obtained by foaming the heated foam sheet according to claim 1.

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