JPH03121836A - Foamed structure - Google Patents

Abstract

PURPOSE:To enhance mechanical performances such as surface smoothness, tension strength, impact strength, bending strength, torsional strength and the like by bonding a fiber plastic layer section with a thermoplastic foamed material with good integrality. CONSTITUTION:As a fiber plastic layer section 2, a high molecular arranged material with its sheath component composed of polyethylene terephthalate with the core component of multi-core sheath type composite fiber composed of polystyrene and sheath component composed of polyethylene terephthalate is jetted toward an opening section in a preheated mold, and a multi-core sheath type composite fiber sheet is provided on the whole of the wall surface of the mold. Then, as for a thermoplastic foamed material section 3, foaming polystyrene beads and high molecular arranged material fibers are mixed and filled in a space of the mold. After filling, the mold is closed and heated by steam, and the sheath component of high molecular arranged material fiber is melted and flowed, and also polystyrene beads are foamed. An integral foamed structure 1 thus manufactured is composed firmly and integrally of a fiber plastic layer section 2 and a thermoplastic foamed material section 3 and is of superior surface smoothness and resistance to impact and also strong to bending and torsion and hard to get cracks.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a foamed structure, and more specifically, a foamed structure in which a composite layer of composite fibers and plastic is integrated with a thermoplastic foam. Regarding the body.

[Prior Art] Thermoplastic foams such as foamed polystyrene, foamed polyethylene, foamed polypropylene, and foamed polyurethane have traditionally been known to have excellent shock absorption, heat insulation, water pressure resistance, electrical insulation, etc., water absorption, and heat resistance. It has characteristics such as low conductivity, low moisture permeability, and light weight, as well as being inexpensive.
Packaging/packaging for electrical products, precision instruments, glass products, crafts, etc., construction/civil engineering fields such as wall materials, curing sheets, roof insulation materials, waterproof layer protection materials, etc., insulation materials for air-conditioning equipment, insulation for freezing prevention. It is widely used in the insulation industry such as moons, in the vehicle industry such as automobile interior materials, and in the sports, household goods, and miscellaneous goods fields such as bath grates, health mats, gym mats, swimming beat boards, etc.

However, conventional thermoplastic foams are extremely brittle against impact and are prone to lose their shape, break, or crack. Because of these problems in terms of mechanical performance, it has been considered an unsuitable material for parts that are subject to strong impact forces, bending, or torsion.

Furthermore, because the surface is rough and lacks smoothness, there are some fields in which there are problems in appearance when used alone, and there is also the drawback that characters, figures, patterns, etc. cannot be clearly printed on the surface. Ta.

[Problems to be Solved by the Invention] An object of the present invention is to solve these problems and provide a foamed structure having excellent mechanical performance and surface smoothness.

[Means for Solving the Problems] In order to achieve the above object, the present invention has the following configuration.

That is, the foamed structure of the present invention is characterized in that a composite layer of fibers and plastic is integrated with a thermoplastic foam, and the composite layer of fibers and plastic forms at least one surface. It is the body.

Further, in the foamed structure of the present invention, preferably, the composite layer of fibers and plastic uses a composite fiber layer as a raw material, and one component of the composite fiber is made into plastic, and other components are left substantially in the form of fibers. This is a foamed structure characterized by being formed by. Further, preferably, the composite fiber is a core-sheath type composite fiber, and the core-sheath type composite fiber is a multilayer fiber containing three or more core components per composite fiber. The foamed structure is a core-sheath type composite fiber, and the sheath component of the multicore-sheath type composite fiber is the same component as a thermoplastic foam, or the multicore-sheath type composite fiber is a foamed structure that is a core-sheath type composite fiber. The core component of is 2
It is a foamed structure composed of more than one different component.

Alternatively, preferably, in the foamed structure of the present invention described above, the thermoplastic foam is reinforced with fibers.

[Function] Hereinafter, the foamed structure of the present invention will be explained in more detail using drawings and the like.

1-3 are schematic cross-sectional views of a model showing one embodiment of the foamed structure of the present invention.

FIGS. 4 to 6 are schematic cross-sectional model diagrams illustrating one embodiment of a composite fiber that can be used in manufacturing the foamed structure of the present invention.

The foamed structure of the present invention is roughly divided into two parts. That is, in FIGS. 1 to 3, 1 indicates the foamed structure of the present invention, 2 indicates a composite layer of fiber and plastic (hereinafter referred to as fiber plastic layer), and 3
is the thermoplastic foam part.

The foamed structure of the present invention has a structure in which the fiber plastic layer is integrated with a thermoplastic foam and forms at least one surface.

Fig. 1 shows the fiber plastic layer 2 and thermoplastic foam 3 bonded together on one side and integrated, and Fig. 2 shows the fiber plastic layer 2 bonded and integrated on both the front and back sides of the thermoplastic foam 3. Furthermore, as shown in FIG. 3, the entire periphery of the thermoplastic foam 3 is covered with the fiber plastic layer 2 and is bonded and integrated. the degree of such integration;
The method of integration greatly affects 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 composited, the fiber plastic layer portion contributes to improvements in performance such as mechanical performance and surface smoothness, and Because the thermoplastic foam part can contribute to performance such as lightness, shock absorption, and heat insulation,
It is possible to have these two performances at the same time. For this reason, it is now possible to apply it to fields that are subject to severe impacts and mechanical effects, and fields that require clear printing on the outer peripheral surface and aesthetic appearance, something that could not be used alone until now. .

In the present invention, the fiber plastic layer may be formed by compositely integrating fibers and plastics and reinforced by the composite effect, and the manufacturing means thereof is not particularly limited, but in particular, composite fibers The entire layer is made into plastic by substantially melting at least one component of the composite fiber in the layer, while the other components remain in fiber form. It is most preferable to leave the fibers in the plastic layer and form a fiber-reinforced plastic layer reinforced by the remaining fibers.

When adopting such a method, it is preferable to use a core-sheath type conjugate fiber as the conjugate fiber, and among them, a multicore-sheath type conjugate fiber, which is a structural fiber having many core components in the sheath component, is particularly preferably used. . That is, as such multi-core sheath type conjugate fibers, for example, conjugate fibers typified by polymer array fibers, mixed spun fibers, etc. can be suitably used.

In addition, in such a multicore sheath type composite fiber, the sheath components include 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. In addition, 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, and carbon fiber are preferable because they have good properties such as tensile strength, impact strength, bending strength, and torsional strength required for the foamed structure of the present invention. used. In this case, consideration must be given to the combination with a sheath component that can be easily made into plastic.

4 to 6, 4 and 4' are core components, and 5 is a sheath component. As shown in FIG. 4, the core components are:
Although the object of the present invention can be sufficiently achieved with the - component, as shown in FIG. It is advantageous for improving performance and is more preferably used.

For example, one core component/two core components/sheath components may be used in appropriate combinations depending on the purpose and use, such as nylon/polyethylene/polystyrene, nylon/polyethylene/polystyrene, nylon/bolyarylate/polystyrene, etc. I can do it. In such a combination, in order to improve the integrity of the fiber plastic layer part and the thermoplastic foam, it is preferable to select a combination of components with good adhesive properties for the thermoplastic foam part and the sheath component of the core-sheath composite fiber. It is particularly preferred to use the same components.

The number and 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 core components, or may be different within the same core component.

The number of core fibers in the composite fiber is preferably in the range of 3 to 10,000, with 1-0 to 1,000 being particularly preferably used. The thickness of the composite fiber is not particularly limited as long as it is suitable for its use as a fiber-reinforced composite, but generally the thickness of the composite fiber is 0.1 to 10.
A range of 0.00 denier is preferred.

The thickness of the core fiber is usually 1/3 to 1/100 of the composite fiber.
About 0 is preferable. Of course, it goes without saying that the thinner the composite fiber and/or core fiber, the better the surface smoothness of the fiber plastic layer.

Such composite fibers may be in the form of long fibers (filaments), short fibers (staples) or similar lengths, chips, flakes, woven fabrics, knitted fabrics, nonwoven fabrics, composites thereof, etc. It may be used in a layered form such as a cloth, molded and made into plastic.

In the above explanation, we have explained in the case of composite fibers, but even when using composite yarns such as mixed yarns or intertwisted yarns that use multiple types of yarns made of the polymers described as the core component or sheath component, Similar fiber reinforced plastic layers can be obtained and such composite yarns may be used in the present invention. Furthermore, even when using composite fibers, it goes without saying that in addition to the core-sheath type described above, bimetal type composite fibers, orange cross-section type composite fibers, petal-shaped composite fibers, or multilayer bonded composite fibers may be used.

Furthermore, materials for the thermoplastic foam portion used in the present invention include polystyrene, polyethylene, polypropylene, polyurethane, ABS resin, vinyl chloride resin, acrylic resin, cellulose acetate resin, etc., and one or more of these resins can be used. are used. In particular, these latent expandable beads are preferably used.

In the present invention, the object of the present invention can be sufficiently achieved even if the thermoplastic foam portion is composed only of foam components.
Additionally, fibers can be used to reinforce the thermoplastic foam sections to improve mechanical performance.

The fibers used for such reinforcement may be made of a single component (single component fiber) or may be a composite fiber. It is particularly preferable to use the same conjugate fiber as the conjugate fiber used in the above-mentioned fiber plastic layer.

In addition, such fibers may have a single component fiber, a composite fiber, or a core component with a circular cross-sectional shape.Although it is sufficient to use a circular cross-sectional shape for boat fishing, so-called multi-component fibers such as triangular, quadrilateral, pentagonal, hexagonal, etc. It may have a so-called roval shape, or it may have an H-shaped, H-shaped, sawtooth-shaped, petal-shaped, etc. cross section. From the viewpoint of the integrity of the thermoplastic foam part and the fiber part, it is preferable that the surface of the fiber be as uneven as possible so that an anchor effect can be obtained.

1 Fiber plastic layer part (F) and thermoplastic foam part (
Although the ratio of H) is not particularly limited, it is usually F/
H=9515 to 5/95 is preferably used.

In the present invention, there is no particular limitation on the method of manufacturing such a foamed structure, and any method may be used.

To give an example of a preferred method, a fully oriented multicore sheath-type composite fiber is blown onto the wall of a molding die that has been heated using an ejector so that about half of the sheath component is melted. The multi-core sheath-type composite fiber sheet (composite fiber layer) is made on the entire wall surface, and then the entire volume of the mold is filled with pre-foamed (primary foamed) beads, and then heated to a heating device. This is achieved by heating the sheath component of the multicore sheath-type composite fiber to a temperature at which it melts and flows, and at which the expandable beads undergo secondary foaming.

By this method, the sheath component of the core-sheath type composite fiber is melted and fluidized, and the sheath component of the multi-core sheath type composite fiber is melted and fluidized on the outer peripheral surface by the foaming energy of the foam beads at 2°C and 70°C. is made into plastic, has a plastic structure reinforced with ultrafine fibers, and the inside is filled with thermoplastic foam. In this case, of course, the multi-core sheath type composite fiber may be used in advance in the form of a fabric such as a woven fabric, knitted fabric, or non-woven fabric.

In addition, when using fibers for reinforcement in the thermoplastic foam part, first spray the multi-core sheath-type composite fiber onto the pre-heated wall surface of the molding mold using an ejector in the same way as above, so that the entire wall surface becomes a multi-core sheath type composite fiber. After forming a composite fiber sheet, latent foaming beads and multi-core sheath type composite fibers are sprayed and mixed into a mold from separate or the same ejector to form a composite fiber sheet that covers 2 to 8 of the internal volume of the mold. This is achieved by filling and mixing to a certain degree, sealing the molding die, and then heating it in a heating device to a temperature at which the sheath component of the multicore sheath-type composite fiber melts and flows, and the latent expandable beads foam. Ru. In addition, when injecting latent expandable beads, there are two methods: injecting pre-expanded particles, supplying and injecting preheated gas so that the beads foam to some extent, or installing a heater at the tip of the ejector. A preferred method is to install the foam, pre-foam it in that area, and then spray it. Further, when the fibers are in the form of a fiber bundle made up of a plurality of single fibers, it is a preferable method to inject the fibers while applying a high voltage to the tip of the injection device, as this improves the separation of the fibers and enhances the reinforcing effect.

The foamed structure of the present invention requires aesthetics such as clear printing and appearance on the outer peripheral surface and in areas subject to severe impact and mechanical action, which conventional thermoplastic foams alone could not be used for. This makes it possible to apply the method to other fields.

Therefore, in addition to improving the performance of conventional applications, the fiber-reinforced composites of the present invention can also be used in new applications such as surfing boards, lightweight, simple toy boxes, prefabricated products, portable toilets, and the like.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples, but the validity and scope of the rights of the present invention are not limited or restricted by these Examples. Rather, it brings about the next application and development.

Example 1 - As a fiber plastic layer portion, a polymer array fiber (number of cores in 1 filament: 16, single fiber fineness: 3° 8 denier, number of filaments = 24) was injected using an ejector toward the opening in a preheated U-shaped molding mold, and a multi-core sheath-type composite fiber sheet was spread over the entire wall of the molding mold. Established.

Next, commercially available expandable polystyrene beads were used as the thermoplastic foam part, and the expandable polystyrene beads and polymer array fibers were mixed and filled into the space of the mold using an ejector. The foamable polystyrene beads were sprayed by supplying compressed air heated to 120° C. to pre-expand the polystyrene beads. When the inner volume of the mold is filled to its fullest, the injection is stopped, the mold is sealed, and heated with steam at 1-05°C to melt the sheath component (polystyrene) of the polymer array fibers. - Polystyrene beads were foamed as they flowed.

The resulting foamed structure is a strong integration of the fiber plastic layer and thermoplastic foam, and has excellent surface smoothness, excellent impact resistance, and is resistant to bending and torsion. , it was difficult to crack.

Using the foamed structure of the present invention, a radio cassette player was packed in combination with the fiber-reinforced composite without wrapping the outside with cardboard, and a transportation test was conducted. As a result, the packaged radio cassette player could be transported without any damage.

On the other hand, when similar tests were conducted using conventional polystyrene foam, the polystyrene foam cracked due to vibration during transportation, the paint on the corners of the radio cassette player came off, and some parts of the equipment were damaged. Ta.

Furthermore, when we printed the product name and pattern on the surface of the foam structure, we were able to print it much more clearly than with conventional polystyrene foam.

6 [Effects of the Invention] As described above, the foamed structure of the present invention has a structure in which the fiber plastic layer portion and the thermoplastic foam are bonded together with good integrity, and has good surface smoothness and tensile strength. It has mechanical properties such as strength, impact strength, bending strength, and torsional strength.

Therefore, it is now possible to apply it to fields subject to severe impact and mechanical effects, which could not be used with conventional thermoplastic foam alone, and it is also possible to print clearly on the outer peripheral surface and improve its appearance. It also becomes possible to apply it to fields that require the following.

In addition, it can be preferably applied to the construction and civil engineering fields, such as mud blowing prevention materials for roads that are subject to severe impact and mechanical action, various civil engineering materials, and waterproof layer protection materials.

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

[Brief explanation of drawings]

FIGS. 1 to 3 are schematic model diagrams showing one embodiment of the foamed structure of the present invention. FIGS. 4 to 6 are schematic cross-sectional model diagrams illustrating one embodiment of a composite fiber that can be used in manufacturing the foamed structure of the present invention. Foamed structure 2: Fiber plastic layer portion 3: Thermoplastic foam 4.4': Core component 5: Sheath component Patent application filed by Daito Shi Co., Ltd. 9 Figure 4 Figure 5 Yadashi 4

Claims (1)

[Claims] (1) A foam structure characterized in that a composite layer of fibers and plastic is integrated with a thermoplastic foam, and the composite layer of fibers and plastic forms at least one surface. . (2) The composite layer of fiber and plastic is formed by using a layer of composite fiber as a raw material, converting one component of the composite fiber into plastic, and leaving other components substantially in the form of fibers. The foamed structure according to claim 1. (3) The foamed structure according to claim 2, wherein the composite fiber is a core-sheath type composite fiber. (4) The foamed structure according to claim 3, wherein the core-sheath type composite fiber is a multicore-sheath type composite fiber containing three or more core components per composite fiber. (5) The foamed structure according to claim 4, wherein the sheath component of the multicore sheath type conjugate fiber is the same as that of the thermoplastic foam. (6) The foamed structure according to claim 4, wherein the core component of the multi-core sheath type composite fiber consists of two or more different components. (7) The foam structure according to claim 1, 2, 3, 4, 5 or 6, wherein the thermoplastic foam is reinforced with fibers.