JP2570215B2 - Method for manufacturing foamed structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a foamed structure, and more particularly to a method for producing a foamed structure in which a composite layer of fibers and plastic is integrated with a thermoplastic foam.

[0002]

2. Description of the Related Art Conventionally, thermoplastic foams such as expanded polystyrene, expanded polyethylene, expanded polypropylene, expanded polyurethane, and the like have excellent shock absorption, heat insulation, water pressure resistance, electrical insulation, etc., water absorption, heat absorption, and the like. It has properties such as low conductivity, low moisture permeability, light weight, etc., and it is inexpensive, so it can be used in the field of packaging and packaging of electrical products, precision equipment, glass products, crafts, etc., wall materials, curing sheets, Construction and civil engineering fields such as roof insulation materials and waterproof layer protection materials, insulation materials for air-conditioning and heating equipment, insulation industry fields such as heat insulation materials for preventing freezing, vehicle fields such as interior materials for automobiles, bath saws, health mats, and sports mats Widely used in sports, household goods, sundries, etc. such as swimming beat boards.

[0003] However, conventional thermoplastic foams are very brittle against impact, so they lose their shape, break,
Cracks were easily generated. And, due to such a problem in terms of mechanical performance, the material is not suitable for a part that receives a strong impact force, or is subject to bending or twisting.

Further, there is a field in which the surface is rough and poor in smoothness, so that there is a problem in appearance when used alone, and it is difficult to clearly print characters, figures or patterns on the surface. There were also disadvantages.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a method for producing a foamed structure having excellent mechanical performance and surface smoothness.

[0006]

In order to achieve the above object, the present invention has the following arrangement.

That is, a method of manufacturing a foamed structure according to the present invention is directed to a method of manufacturing a foamed structure in which a composite layer of fiber and plastic and a thermoplastic foam are integrated with each other. A composite fiber or a composite yarn as a raw material, at least one component of the composite fiber or the composite yarn is composed of a component that adheres to the thermoplastic foam by heating and melting, and a layer of the composite fiber or the composite yarn; By heating the foam, the composite fibers or the composite yarns are fused and integrated together, and the layer of the composite fiber or the composite yarn and the thermoplastic foam are fused and integrated. .

In the method for producing a foamed structure of the present invention, preferably, the conjugate fiber is a core-sheath conjugate fiber, and the core-sheath conjugate fiber is A multi-core sheath composite fiber containing three or more core components per composite fiber, and the sheath component of the multi-core sheath composite fiber is the same as the thermoplastic foam, or the multi-core sheath composite fiber The core component of the composite fiber is composed of two or more different components.

[0009] Alternatively, preferably, the thermoplastic foam is reinforced by fibers.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the method for producing a foamed structure of the present invention will be described in more detail with reference to the drawings and the like.

FIG. 1 to FIG. 3 are schematic model sectional views schematically showing one embodiment of a foamed structure obtained by the manufacturing method of the present invention.

FIGS. 4 to 6 are schematic cross-sectional views schematically showing one embodiment of a composite fiber which can be used in producing the foamed structure of the present invention.

The foamed structure obtained by the present invention is roughly divided into two parts. That is, FIG.
3, reference numeral 1 denotes a foamed structure obtained by the present invention, 2 denotes a composite layer of fiber and plastic (hereinafter, referred to as a fiber plastic layer), and 3 denotes a thermoplastic foam part.

The foamed structure obtained by the present invention has such a structure that at least one surface is formed by integrating the fibrous plastic layer with the thermoplastic foam.

FIG. 1 shows a fiber plastic layer 2 and a thermoplastic foam 3 bonded and integrated on one surface.
FIG. 3 shows that the fiber plastic layer 2 is bonded and integrated on both the front and back surfaces of the thermoplastic foam 3, and FIG. 3 shows that the entire periphery of the thermoplastic foam 3 is covered with the fiber plastic layer 2 and bonded. It is integrated. The degree of such integration and the manner of integration greatly affect the performance of the foamed structure of the present invention. That is, since both the above-mentioned fiber plastic layer 2 and thermoplastic foam 3 are integrated and combined, the fiber plastic layer portion contributes to improvement of performance such as mechanical performance and surface smoothness. Since the thermoplastic foam part can contribute to performance such as light weight, shock absorption, heat insulation, and the like, it is possible to simultaneously have these two performances. For this reason, it can be applied to fields where severe impact or mechanical action could not be used alone or fields where clear printing on the outer peripheral surface and aesthetic appearance are required. .

In the present invention, the fibrous plastic layer comprises
Using a layer made of a conjugate fiber as a raw material layer, at least one component of the conjugate fiber in the layer is substantially melted to melt and integrate the conjugate fibers into a plastic, and a layer of the conjugate fiber is formed. One component of the composite fiber is melt-fused with a thermoplastic foam to be integrated.
At this time, at least one component of the composite fiber is melted to be plasticized, while the other component is left in the plasticized layer in a fibrous form, and is reinforced by the remaining fiber. It is formed as a layer. When one component is made into plastic, it is melt-integrated with one component of another conjugate fiber and a thermoplastic foam, but depending on the degree of plasticization, the form of conjugate fiber is partially maintained.

When employing this method, it is preferable to use a core-sheath conjugate fiber as the conjugate fiber, and in particular, a multi-core sheath conjugate fiber which is a structural fiber having a large number of core components in the sheath component. It is preferably used. That is, as such a multi-core sheath type composite fiber, for example, a composite fiber represented by a polymer array fiber, a mixed spun fiber, or the like can be suitably used.

In the multi-core sheath type composite fiber,
As the sheath component, polystyrene, polystyrene / acrylonitrile copolymer, polymethyl methacrylate, polymethyl methacrylate / polystyrene / acrylonitrile copolymer, polyamide, polyamide copolymer, polyester, polyester copolymer, polyethylene, polypropylene, A polyvinyl compound or the like is used. Also,
As the core component, polyester such as polyethylene terephthalate, polyester copolymer, polyamide, polyamide copolymer, polyarylate, polyethylene, polypropylene, polyurethane, carbon fiber, etc. are used. Among these components, polyethylene terephthalate, polybutylene Terephthalate, polyamide, polyethylene,
Polypropylene, polyarylate, carbon fiber is required tensile strength as a foam structure obtained by the present invention,
Excellent in properties such as impact strength, bending and torsional strength,
It is preferably used. In this case, consideration must be given to a combination with a sheath component that can be easily made into plastic.

In FIGS. 4 to 6, reference numerals 4 and 4 'denote a core component and 5 a sheath component. As shown in FIG. 4, one component can sufficiently achieve the object of the present invention. FIG.
As shown in the above, those in which the core component is composed of two or more kinds of 4, 4 'can simultaneously and widely select the properties of the reinforcing fiber, and are advantageous and more preferably used for enhancing the fiber performance.

For example, one core component / two core components / sheath component is
Nylon / polypropylene / polystyrene, nylon / polyethylene / polystyrene, nylon / polyarylate / polystyrene and the like can be used in an appropriate combination depending on the purpose and application. In such a combination, in order to enhance the integrity of the fiber plastic layer portion and the thermoplastic foam, it is preferable to select a combination of components having good adhesiveness for the thermoplastic foam portion and the sheath component of the core-sheath composite fiber. It is particularly preferred to use the same components.

The number and the component ratio of the core 1 component and the core 2 component are not limited. Further, the thickness may be the same or different between the core components, and may be different among the same core components.

The number of core fibers in the composite fiber is 3 to 10
Preferably, the number is in the range of 10 to 1,000.
Books are particularly preferably used. The thickness of the composite fiber may be a fiber-reinforced composite suitable for the application,
Although not particularly limited, generally, a range of 0.1 to 1000 denier for a conjugate fiber is preferable.

The thickness of the core fiber is usually 1/3 of that of the composite fiber.
About 1/1000 is preferable. Of course, it goes without saying that the thinner the composite fiber and / or the core fiber, the better the surface smoothness of the fibrous plastic layer.

Such conjugate fibers may be in the form of long fibers (filaments), cut into short fibers (staples) or similar lengths, cut into chips, flakes, or woven, knitted, non-woven fabrics or the like. What is necessary is just to shape | mold and process by using it in the form of layers, such as cloths, such as a composite, and to make it plastic.

In the above description, the case of a conjugate fiber has been described. However, a yarn made of the polymer described as the core component or the sheath component, or a composite yarn using a plurality of types of such yarns, such as a mixed fiber yarn or a twisted yarn. In use, it is possible to obtain a fiber-reinforced plastic layer substantially equivalent to the case of using the above-described composite fiber, and in the present invention, such a composite yarn may be used. Further, such a composite yarn may be mixed with the above-described composite fiber. Further, even when using a conjugate fiber, it goes without saying that a bimetal conjugate fiber, an orange cross-section conjugate fiber, a petal-like conjugate fiber, a multi-layer conjugate fiber, or the like may be used in addition to the core-sheath type.

The material of the thermoplastic foam used in the present invention includes polystyrene, polyethylene, polypropylene, polyurethane, ABS resin, vinyl chloride resin, acrylic resin, cellulose acetate resin, and the like.
One or more of these are used. In particular, these latently expandable beads are preferably used.

In the present invention, the thermoplastic foam part comprises:
Although the object of the present invention can be sufficiently achieved even if it is constituted only by the foam component, it is also possible to reinforce the thermoplastic foam portion by using fibers in order to further improve the mechanical performance.

As the conjugate fiber, it is particularly preferable to use the same conjugate fiber as used in the fibrous plastic layer.

In general, the cross-sectional shape of the whole fiber or each component of such a conjugate fiber may be a circular one, but may be a so-called multi-lobal such as triangular, quadrangular, pentagonal or octagonal. The shape may be any of the shapes mentioned above, or may have a cross section such as an H shape, a Π shape, a saw shape, a petal shape, and a swastika shape. In terms of the integrity of the thermoplastic foam part and the fiber part,
It is preferable that the surface of the fiber is as uneven as possible, and the fiber has an anchor effect.

The ratio between the fiber plastic layer portion (F) and the thermoplastic foam portion (H) is not particularly limited, but usually F / H = 95/5 to 5/95 is preferably used.

As an example of the preferred method of the present invention, a multi-core sheath type composite fiber which is stretched and sufficiently oriented is heated by an ejector so that the sheath component is previously melted by about half. The multi-core sheath type composite fiber sheet (composite fiber layer) is made by spraying on the wall of the mold,
Next, the beads that have been pre-expanded (primary expanded) are filled in the entire volume of the molding die, and then put into a heating device so that the sheath component of the multi-core sheath-type composite fiber is melted and flowed. This is achieved by heating to a temperature at which secondary foaming occurs. By such a method, the sheath component of the core-sheath composite fiber melts and flows, and the expandable beads foam, and the foaming energy causes the sheath component of the multi-core sheath composite fiber to become plastic on the outer peripheral surface, And it has a plastic structure reinforced with microfibers, the interior of which is filled with a thermoplastic foam. In this case, as a matter of course, the multi-core sheath type conjugate fiber may be in the form of a fabric such as a woven fabric, a knitted fabric, or a non-woven fabric in advance.

In the case where the fiber is also used for reinforcing the thermoplastic foam portion, first, similarly to the above, the multi-core sheath type composite fiber is sprayed onto the wall surface of the molding die heated in advance by an ejector to cover the entire wall surface. After forming the core-sheath composite fiber sheet, the beads having latent foaming properties and the multi-core sheath composite fiber are separately mixed or jet-mixed from the same ejector toward the molding die to reduce the inner volume of the molding die. After filling and mixing about 20 to 80% and closing the molding die, put it in a heating device and heat it to a temperature at which the sheath component of the multi-core sheath type composite fiber melts and flows and expands the latent expandable beads. Is achieved by Also, when injecting the latent expandable beads, a method of injecting pre-expanded particles, a method of supplying and injecting a pre-heated gas so that the beads expand to some extent, or attaching a heater to the cylinder end of the ejector A method of prefoaming and spraying at that portion is preferably performed. In the case where the fibers are in the form of a fiber bundle in which a plurality of single fibers are aggregated, if a high voltage is applied to the tip of the injection device and the injection is performed, the separation of the fibers is improved and the reinforcing effect is enhanced.

The foamed structure obtained by the present invention can be used for a field subjected to severe impact or mechanical action, which cannot be used by conventional thermoplastic foams alone, or for a clear print on the outer peripheral surface and appearance. It is also possible to apply to fields that require aesthetics.

Therefore, the fiber-reinforced foamed structure obtained by the present invention can be used not only for improving the performance of conventional applications but also for new applications such as surfboards, lightweight, simple cooler boxes, prefabs, and moving toilets. Can also.

[0035]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which by no means limit or limit the effectiveness and scope of the present invention. Rather, they bring about the following applications and developments.

Example 1 As a fibrous plastic layer portion, a multi-core sheath type composite fiber was composed of a polymer array fiber composed of polystyrene as the sheath component and polyethylene terephthalate as the core component (the number of cores in one filament: 16, the fineness of single yarn: 3.8 denier, number of filaments: 24) is sprayed toward an opening in a U-shaped molding die heated in advance using an ejector, and the multi-core sheath type composite fiber is applied to the entire wall surface of the molding die. A sheet was provided.

Next, a commercially available expandable polystyrene bead was used as the thermoplastic foam part, and the expandable polystyrene bead and the polymer array fiber were mixed and filled in the space of the molding die using an ejector. The injection of the expandable polystyrene beads was performed by supplying compressed air heated to 120 ° C. to pre-expand the polystyrene beads.
When the inside of the molding die is completely filled, the injection is stopped, the molding die is closed, and the mixture is heated by steam at 105 ° C., and the sheath component of the polymer array fiber (polystyrene)
Melted and flowed, and the polystyrene beads were foamed. The resulting foamed structure is one in which the fiber plastic layer portion and the thermoplastic foam portion are firmly integrated,
It excelled in surface smoothness, had excellent impact resistance, was strong against bending and twisting, and was hardly cracked.

Using the foamed structure obtained according to the present invention, a boombox was packaged in combination with the fiber-reinforced composite without wrapping the outside with cardboard, and a transport test was conducted. As a result, it was possible to transport the boombox as a packaged item without any damage.

On the other hand, when a similar test was conducted using a conventional polystyrene foam, the polystyrene foam was broken due to vibration during transportation, and the paint on the corners of the boombox was peeled off, and a part of the equipment was damaged. Was observed.

Further, when a product name and a pattern are printed on the surface of the foamed structure, the printing has been performed so clearly that it cannot be compared with the conventional polystyrene foam.

[0041]

As described above, the foamed structure obtained by the present invention has a structure in which the fiber plastic layer portion and the thermoplastic foam are adhered to each other with good integrity, and has good surface smoothness and tensile strength. It has mechanical properties such as strength, impact strength, bending and torsional strength.

Therefore, the present invention can be applied to a field which is subjected to severe impact or mechanical action, which cannot be used by the conventional thermoplastic foam alone. It is also possible to apply to the field where the beauty etc. is required.

In addition, the present invention can be preferably applied to construction and civil engineering fields such as road mud preventive materials, various civil engineering materials, and waterproof layer protective materials which are subjected to severe impact and mechanical action.

In addition, it can be preferably used in the heat insulation industry, the field of vehicles such as automobiles, the field of packaging and packing, and the field of sports and miscellaneous goods.

[Brief description of the drawings]

FIG. 1 is a schematic model diagram schematically showing an embodiment of a foamed structure obtained by the present invention.

FIG. 2 is a schematic model diagram schematically showing another embodiment of the foamed structure obtained by the present invention.

FIG. 3 is a schematic model diagram schematically showing still another embodiment of the foamed structure obtained by the present invention.

FIG. 4 is a schematic cross-sectional model diagram schematically illustrating an embodiment of a composite fiber that can be used in the production method of the present invention.

FIG. 5 is a schematic cross-sectional model diagram schematically illustrating another embodiment of a conjugate fiber that can be used in the production method of the present invention.

FIG. 6 is a schematic cross-sectional model showing a model of yet another embodiment of a conjugate fiber that can be used in the production method of the present invention.

[Explanation of symbols]

 1: foamed structure 2: fiber plastic layer 3: thermoplastic foam 4, 4 ': core component 5: sheath component

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B29L 9:00

Claims (6)

(57) [Claims] 1. A method for producing a foamed structure in which a composite layer of fiber and plastic and a thermoplastic foam are integrated, wherein the composite layer of fiber and plastic is made of a composite fiber or a composite yarn as a raw material. At least one component of the composite fiber or the composite yarn is composed of a component that adheres to the thermoplastic foam by heating and melting, and the layer of the composite fiber or the composite yarn and the thermoplastic foam are heated to form the composite. A method for producing a foamed structure, characterized in that fibers or composite yarns are fused and integrated, and a layer of the composite fiber or composite yarn and a thermoplastic foam are fused and integrated. 2. The method according to claim 1, wherein the conjugate fiber is a core-sheath conjugate fiber. 3. The method for producing a foamed structure according to claim 2, wherein the core-sheath type conjugate fiber is a multi-core sheath type conjugate fiber containing three or more core components per conjugate fiber. 4. The method for producing a foamed structure according to claim 3, wherein the sheath component of the multi-core sheath type composite fiber is the same as that of the thermoplastic foam. 5. The method for producing a foamed structure according to claim 3, wherein the core component of the multi-core sheath type composite fiber comprises two or more different components. 6. The thermoplastic foam as claimed in claim 1, wherein the thermoplastic foam is reinforced by fibers.
A method for producing the foamed structure according to the above.