JP2019166709A - Multilayer fiber-containing resin molding - Google Patents

Abstract

To provide a multilayer fiber-containing resin molding having excellent rigidity and also excellent impact resistance.SOLUTION: A multilayer fiber-containing resin molding 1 has: a substrate layer 2 containing a thermoplastic resin and a plant fiber; and an impact absorption layer 3 that has a thermoplastic resin, a plant fiber and a high strength fiber, and is laminated on one side of the substrate layer 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a multilayer fiber-containing resin molded body.

  Conventionally, fiber-containing resin moldings obtained by heating and pressing a mixture of plant fibers and thermoplastic resins (fibers) are door trim base materials, inner panels, pillar garnishes, rear packages, ceiling base materials, shock absorbers, sound absorbing materials. Widely used as interior materials for vehicles such as materials; building materials such as wall materials, floor materials, under-floor shock absorbers and heat insulating materials; and equipment materials such as speaker boxes and sound absorbing materials (see, for example, Patent Document 1) ).

JP 2001-179716 A

  As a fiber material, a fiber-containing resin molded body containing only plant fibers is lightweight and rigid, but there are cases where impact resistance is not sufficient.

  An object of the present invention is to provide a multilayer fiber-containing resin molded body having excellent rigidity and excellent impact resistance.

  The multilayer fiber-containing resin molded body according to the present invention includes a base material layer containing a thermoplastic resin and a vegetable fiber, and includes a thermoplastic resin, a vegetable fiber and a high strength fiber, on one surface side of the base material layer. A shock absorbing layer to be laminated.

  In the multilayer fiber-containing resin molded body, the content of the high-strength fiber in the shock absorbing layer is 25% by mass or more, and the thickness (d1) of the shock absorbing layer and the thickness (d2) of the base material layer The ratio (d1 / (d1 + d2)) of the thickness (d1) of the shock absorbing layer to the total thickness (d1 + d2) is 0.1 or more, and the puncture in the puncture impact test according to JIS K7211-2: 2006 The energy absorption amount is preferably 5.0 J or more.

  In the multilayer fiber-containing resin molded body, the thermoplastic resin of the base material layer is made of a polyolefin resin, the thermoplastic resin of the shock absorbing layer is made of a polyolefin resin, and the shock absorbing layer is The content of the acid-modified polyolefin resin is preferably 1.2% by mass or less.

  In the multilayer fiber-containing resin molded body, the intermediate film includes a core layer and a pair of adhesive layers respectively laminated on both sides of the core layer, and is interposed between the base material layer and the shock absorbing layer It is preferable to provide.

  In the multilayer fiber-containing resin molded product, the tensile strength of the high strength fiber is preferably 27 GPa or more.

  ADVANTAGE OF THE INVENTION According to this invention, the multilayer type fiber containing resin molding which is excellent also in impact resistance while providing the outstanding rigidity can be provided.

Explanatory drawing which represented typically the cross-sectional structure of the multilayer type fiber containing resin molding of this embodiment Explanatory drawing which represented typically the cross-sectional structure of the multilayer type fiber containing resin molding which concerns on other embodiment. Explanatory drawing enlarging the cross-sectional configuration of the intermediate film The graph which shows the measurement result of puncture energy absorption amount and puncture displacement amount of Examples 1-3 and Comparative Examples 1-6

  The multilayer fiber-containing resin molded body of this embodiment will be described with reference to FIG. FIG. 1 is an explanatory view schematically showing a cross-sectional configuration of a multilayer fiber-containing resin molded body 1 of the present embodiment. The multilayer fiber-containing resin molded body 1 includes a base material layer 2 and a shock absorbing layer 3 laminated on one surface side of the base material layer 2.

  The base material layer 2 contains a thermoplastic resin and plant fibers.

  The thermoplastic resin is not particularly limited, and examples thereof include polyolefin resins such as polypropylene, polyethylene, and ethylene / propylene random copolymers; aliphatic polyester resins such as polylactic acid, polycaprolactone, and polybutylene succinate; polyethylene terephthalate; Polyester resins such as aromatic polyester resins such as polytrimethylene terephthalate and polybutylene terephthalate; polystyrenes; acrylic resins; polyamide resins; polycarbonate resins; polyacetate resins; The thermoplastic resin may be modified (acid anhydride modified, carboxylic acid modified, epoxy modified or oxazoline modified) in order to increase the affinity for the surface of the plant fiber. The thermoplastic resins may be used alone or in combination of two or more. The thermoplastic resin is preferably a polyolefin resin and a polyester resin, and more preferably a polyolefin resin such as polypropylene.

  In particular, as the thermoplastic resin used for the base material layer 2, it is preferable that the polyolefin-based resin includes an acid-modified polyolefin-based resin modified with an acid anhydride such as maleic anhydride.

  The content ratio (content ratio) of the thermoplastic resin contained in the base material layer 2 is based on the whole base material layer 2 from the viewpoint of ensuring adhesion to other layers such as the shock absorbing layer 3 to be laminated. The content is preferably 5 to 80% by mass, more preferably 30 to 70% by mass.

  The plant fiber is not particularly limited, and fibers derived from stems, stems, branches, leaves, roots, and the like in plants may be included as they are, and these include heat treatment, drying treatment, pulverization treatment, chemical treatment, and the like. May be processed. The plant fiber is preferably kenaf, jute hemp, manila hemp, sisal hemp, cocoon, cocoon, cocoon, banana, pineapple, coconut palm, corn, sugar cane, bagasse, palm, papyrus, cocoon, esparto, surabigrass, wheat, rice, It is a linear fibrous body derived from bamboo, conifers (cedar, birch, etc.), hardwoods, cotton and the like. Among these, the mallow is a plant that has a woody stem, is an extremely fast growing annual plant, has an excellent carbon dioxide absorption, contributes to reducing the amount of carbon dioxide in the atmosphere, effective use of forest resources, etc. Particularly preferred is a linear fiber body (kenaf fiber) derived from kenaf. Examples of the kenaf include hibisuc cannabinus and hibisuc sabdariffa in scientific names, and red sesame, cuban kenaf, western hemp, taykenaf, mesta, bimli, ambari and bombay hemp in common names.

  The plant fiber is usually solid, and its length (fiber length) and outer diameter (fiber diameter) are not particularly limited. The upper limit of the fiber length is preferably 150 mm. In addition, the average value of the fiber length is preferably 10 mm to 100 mm, more preferably 30 mm to 80 mm. The upper limit of the fiber diameter is preferably 1500 μm. The average fiber diameter is preferably 20 μm to 500 μm, more preferably 20 μm to 200 μm.

  The shape of the vegetable fiber contained in the base material layer 2 is not particularly limited. The shape in the length direction can be a straight line, a broken line, a curved line, a spiral, or a deformed form thereof. The outer shape of the cross section may be a circle, an ellipse, a polygon, or a deformed shape thereof.

  The content ratio (content ratio) of the plant fiber contained in the base material layer 2 is preferably 20 to 95% by mass with respect to the whole base material layer 2 from the viewpoint of maintaining the structure of the base material layer 2 and the like. Preferably it is 30-70 mass%.

  The base material layer 2 can further contain other components in addition to the thermoplastic resin and the plant fiber. Examples of other components include additives, balloons, and the like that are conventionally included in known thermoplastic resin molded products.

  The shock absorbing layer 3 contains a thermoplastic resin, a vegetable fiber and a high strength fiber.

  The thermoplastic resin used for the shock absorbing layer 3 is basically the same as the thermoplastic resin of the base material layer 2 described above. Therefore, as the thermoplastic resin of the shock absorbing layer 3, those exemplified in the description of the thermoplastic resin of the base material layer 2 can be appropriately used. The thermoplastic resin of the shock absorbing layer 3 is preferably a polyolefin resin and a polyester resin, and more preferably a polyolefin resin such as polypropylene.

  As the thermoplastic resin of the shock absorbing layer 3, as in the case of the base material layer 2, modified (acid anhydride modified, carboxylic acid modified, epoxy modified or oxazoline modified) may be used. However, a modified thermoplastic resin (for example, an acid-modified polyolefin resin modified with an acid anhydride such as maleic anhydride) has an impact-absorbing layer because the affinity with high-strength fibers becomes too high. It is preferably not used as a thermoplastic resin for 3.

  The content ratio (content ratio) of the thermoplastic resin contained in the shock absorbing layer 3 is based on the entire shock absorbing layer 3 from the viewpoint of ensuring adhesion to other layers such as the base material layer 2 to be laminated. , Preferably 30 to 55 mass%, more preferably 30 to 70 mass%.

  Moreover, it is preferable that the content rate (content rate) of the modified thermoplastic resin (for example, acid-modified polyolefin-type resin) contained in the shock absorption layer 3 is 1.2 mass% or less.

  The vegetable fiber used for the shock absorbing layer 3 is basically the same as the vegetable fiber of the base material layer 2 described above. Therefore, as the vegetable fiber of the shock absorbing layer 3, those exemplified in the description of the vegetable fiber of the base material layer 2 can be appropriately used.

  The content ratio (content rate) of the vegetable fiber contained in the shock absorbing layer 3 is preferably 10 to 95% by mass, more preferably, based on the entire shock absorbing layer 3 from the viewpoint of maintaining the structure of the shock absorbing layer 3 and the like. Is 30-70 mass%.

  The high-strength fiber is a fiber having a tensile modulus measured according to JIS L 1015 or JIS L 1013, preferably 27 GPa or more, more preferably 40 GPa or more, still more preferably 50 GPa or more, and particularly preferably 60 GPa or more. Examples of the high-strength fibers include aramid fibers (para-type or meta-type), polyparaphenylene benzobisoxazole fibers (hereinafter referred to as “PBO fibers”), carbon fibers, glass fibers, silicon carbide fibers, PBT fibers, and polyamideimide fibers. , Polyimide fiber, polyarylate fiber, polyazomethine fiber and the like. The high-strength fibers contained in the shock absorbing layer 3 may be only one type or two or more types. The high-strength fiber is preferably at least one selected from an aramid fiber, a PBO fiber, a carbon fiber, and a glass fiber, and particularly preferably an aramid fiber.

  In the case of these fibers, the thermoplastic resin is preferably a resin having low affinity with plant fibers, that is, a non-modified thermoplastic resin, particularly preferably a non-modified thermoplastic resin, from the viewpoint of impact resistance. Polyolefin resin. For example, when the thermoplastic resin includes a non-modified polyolefin-based resin, when the impact absorbing layer 3 receives an impact, the impact energy is converted into friction energy, while the remaining impact energy is received by the high-strength fiber, In order to follow the high-strength fiber to which the plastic resin is sufficiently bonded, the impact absorbing layer 3 is excellent not only in rigidity but also in impact resistance.

  The high-strength fibers are usually solid, and the length (fiber length) and outer diameter (fiber diameter) are not particularly limited. The upper limit of the fiber length is preferably 150 mm. In addition, the average value of the fiber length is preferably 10 mm to 100 mm, more preferably 30 mm to 80 mm. The upper limit of the fiber diameter is preferably 1000 μm. In addition, the average value of the said fiber diameter becomes like this. Preferably they are 3 micrometers-500 micrometers, More preferably, they are 3 micrometers-100 micrometers.

  The high-strength fiber contained in the shock absorbing layer 3 may be in any form of a fiber-like single fiber, a filament-like fiber bundle, and a tow-like twisted fiber. Moreover, the shape of the said high strength fiber is not specifically limited. The shape in the length direction can be a straight line, a broken line, a curved line, a spiral, or a deformed form thereof. The outer shape of the cross section may be a circle, an ellipse, a polygon, or a deformed shape thereof.

  The content (content rate) of the high-strength fibers contained in the shock absorbing layer 3 is not particularly limited as long as the object of the present invention is not impaired, but is preferably 25% by mass or more, more preferably 30% by mass or more, Preferably it is 85 mass% or less, More preferably, it is 70 mass% or less.

  The shock absorbing layer 3 can further contain other components in addition to the thermoplastic resin, the plant fiber, and the high strength fiber. As other components, as in the case of the base material layer 2, conventionally, additives, balloons, and the like included in known thermoplastic resin molded products can be used.

  The total thickness (d1 + d2) of the thickness (d1) of the shock absorbing layer 3 and the thickness (d2) of the base material layer 2 is not particularly limited as long as the object of the present invention is not impaired. It is 5 mm or more, more preferably 2.0 mm or more, preferably 3.0 mm or less, more preferably 2.7 mm or less.

  The ratio (d1 / (d1 + d2)) of the thickness (d1) of the shock absorbing layer to the total thickness (d1 + d2) of the thickness (d1) of the shock absorbing layer 3 and the thickness (d2) of the base material layer 2 is As long as the purpose is not impaired, there is no particular limitation. For example, it is preferably 0.1 or more, more preferably 0.15 or more, preferably 0.9 or less, more preferably 0.8 or less. is there.

  The multilayer fiber-containing resin molded body 1 has a puncture energy absorption amount of 5.0 J or more in a puncture impact test. The contents of the puncture impact test will be described later.

  The method for producing the multilayer fiber-containing resin molded body 1 is not particularly limited, but a preferred production method is that a fiber mixture for the base material layer 2 containing plant fibers and a molten thermoplastic resin, plant fibers, and This is a method in which a laminate of a high-strength fiber and a fiber mixture for the shock absorbing layer 3 containing a molten thermoplastic resin is conventionally subjected to a known molding step.

  The fiber mixture for the base material layer 2 is, for example, a base material layer 2 obtained by mixing (mixing) a thermoplastic resin molded body (for example, pellets, fibrous materials, etc.) and plant fibers. The fiber assembly can be made.

  The fiber mixture for the impact absorbing layer 3 is obtained, for example, by mixing (mixing) a thermoplastic resin molded body (for example, pellets, fibrous materials, etc.), plant fibers, and high-strength fibers. The obtained fiber assembly for the shock absorbing layer 3 can be obtained.

  The molded body of the thermoplastic resin is preferably a thermoplastic fiber, and the shape thereof may be any of a linear shape, a curved shape, a spiral shape, and the like. The fiber length of the thermoplastic resin fiber is preferably 30 mm or more, more preferably 30 mm to 100 mm, and still more preferably 30 mm to 70 mm. When the fiber length is 30 mm or more, it is easy to obtain sufficient entanglement between the thermoplastic resin fibers and sufficient entanglement between the thermoplastic resin fibers and the plant fibers. Therefore, the base material layer 2 in which the vegetable fibers are uniformly dispersed and the impact absorbing layer 3 in which the vegetable fibers and the high-strength fibers are uniformly dispersed can be efficiently produced by the subsequent molding process. Although the fiber diameter of the said thermoplastic resin fiber is not specifically limited, Preferably it is 5 micrometers-100 micrometers, More preferably, they are 20 micrometers-100 micrometers, More preferably, they are 30 micrometers-100 micrometers. The plant fibers and high-strength fibers used for forming each fiber assembly are as described above.

  When the base material layer 2 is formed, the amount of the thermoplastic resin fiber and the plant fiber used is such that the puncture energy absorption amount in the puncture impact test of the multilayer fiber-containing resin molded body 1 is 5.0 J or more. There is no particular limitation.

  The amount of the thermoplastic resin fiber, plant fiber and high strength fiber used in forming the impact absorbing layer 3 is the amount of puncture energy absorbed in the puncture impact test of the multilayer fiber-containing resin molded product 1 is 5. If it becomes 0J or more, there is no particular limitation, but for example, it is appropriately set so that the content of high-strength fibers in the shock absorbing layer 3 is 25% by mass or more.

  When forming the fiber aggregate for the base material layer 2 and the fiber aggregate for the shock absorbing layer 3, the airlaid method, the card method, etc. can be applied, and then entangled as necessary. .

  The fiber aggregate for the shock absorbing layer 3 is placed on the fiber aggregate for the base material layer 2, and the obtained multilayer fiber aggregate is at a temperature at which the thermoplastic resin fibers melt and has high strength. Heating at a temperature at which the fibers and plant fibers are not melted or the like, and pressing using a mold or the like, the multilayer shaped fiber-containing resin molded body 1 having a predetermined shape is obtained. The base material layer 2 and the shock absorbing layer 3 are fixed by melting the thermoplastic resin fibers contained therein and bonding them to each other.

  The multilayer fiber-containing resin molded body 1 has excellent impact resistance performance while having excellent rigidity. Therefore, the multilayer fiber-containing resin molded body 1 is used in various applications such as door trim base materials, inner panels, pillar garnishes, rear packages, ceiling base materials, impact absorbing materials, sound absorbing materials, and other vehicle interior materials and building materials. be able to. The multilayer fiber-containing resin molded body 1 is usually used in such a manner that the impact absorbing layer 3 side is arranged on the side where it is likely to receive an external force directly. That is, the external force (impact) is used in a form that is applied from the shock absorbing layer 3 side.

  The multilayer fiber-containing resin molded body 1 has a configuration in which high-strength fibers are concentrated in the shock absorbing layer 3. That is, the shock absorbing layer 3 is a high density layer of high strength fibers. Such a multilayer fiber-containing resin molded body 1 has a predetermined thickness and a shock absorbing layer 3 having a predetermined amount of high-strength fibers on the impact receiving side. It can absorb energy. In short, even if high strength fibers are not blended on the base material layer 2 side, impact energy can be effectively absorbed by blending a predetermined amount of high strength fibers only on the impact absorbing layer 3 side. . High-strength fibers are very expensive compared to general thermoplastic resins and the like, and it is desired to suppress the amount of use from the viewpoint of manufacturing cost. Therefore, it can be said that the multilayer fiber-containing resin molded body 1 of the present embodiment has an advantageous configuration from the viewpoint of manufacturing cost.

  The multilayer type fiber-containing resin molded body 1 may include other layers in addition to the base material layer 2 and the impact absorbing layer 3 as long as the object of the present invention is not impaired.

  FIG. 2 is an explanatory view schematically showing a cross-sectional configuration of a multilayer fiber-containing resin molded body 1A according to another embodiment. The multilayer fiber-containing resin molded body 1 </ b> A of this embodiment includes an intermediate film 4 in addition to the base material layer 2 and the impact absorbing layer 3. In addition, the basic composition of the base material layer 2 and the shock absorbing layer 3 included in the multilayer fiber-containing resin molded body 1A of the present embodiment is the same as that of the multilayer fiber-containing resin molded body 1 described above. Therefore, those descriptions are omitted.

  The intermediate film 4 has a function of relieving the external force (impact) received by the multilayer fiber-containing resin molded body 1 </ b> A, and is interposed between the base material layer 2 and the shock absorbing layer 3. FIG. 3 is an explanatory diagram in which the cross-sectional configuration of the intermediate film 4 is enlarged. The intermediate film 4 has a very small thickness as compared with the base material layer 2 and the shock absorbing layer 3. The thickness (total thickness) of the intermediate film 4 is not particularly limited as long as the object of the present invention is not impaired, but is, for example, 30 μm to 200 μm (preferably 50 μm to 150 μm).

  As shown in FIG. 3, the intermediate film 4 is multi-layered and includes at least a three-layer structure including a core layer 40 and a pair of adhesive layers 41 and 42 laminated on both sides of the core layer 40. Yes. The core layer 40 is made of a thermoplastic resin layer (film) having appropriate rigidity, strength, etc., such as polyamide. In addition, the core layer 40 uses what does not melt even if it heats at the time of manufacture of the multilayer type fiber-containing resin molding 1. The adhesive layers 41 and 42 are made of a layer (film) of a thermoplastic resin (binder resin) having adhesiveness to the core layer 40 and adhesiveness to the base material layer 2 and the shock absorbing layer 3. Examples of the thermoplastic resin constituting the adhesive layers 41 and 42 include polyolefin resins such as polyethylene and polypropylene.

  The intermediate film 4 is interposed between the base material layer 2 and the shock absorbing layer 3 so as to be in full contact with the surface of the base material layer 2 and the surface of the shock absorbing layer 3. In addition, unless the objective of this invention is impaired, the form which the intermediate film 4 may contact partially with respect to the surface of the base material layer 2 and the surface of the shock absorption layer 3 may be sufficient. In addition, the intermediate film 4 may be provided with a plurality of holes provided so as to penetrate in the thickness direction.

  The multilayer fiber-containing resin molded body 1A was obtained, for example, by placing the intermediate film 4 on the fiber aggregate for the base material layer 2 and further placing the fiber aggregate for the shock absorbing layer 3 thereon. As in the above embodiment, the multilayer fiber assembly is obtained by heating at a predetermined temperature and pressing it using a mold or the like.

  When the multilayer fiber-containing resin molded body 1A receives an impact from the impact absorbing layer 3 side, the interface between the core layer 40 and the one adhesive layer 41 of the intermediate film 4 or the core layer 40 and the other adhesive layer 42 is received. Peeling (delamination) is likely to occur at the interface between the two. When such peeling (delamination) occurs, impact energy is easily absorbed while the breakage of the multilayer fiber-containing resin molded body 1A is suppressed.

  Hereinafter, the present invention will be described in more detail based on examples. In addition, this invention is not limited at all by these Examples.

[1. material〕
(Plant fiber)
As a plant fiber, a kenaf fiber having an average diameter of 0.05 mm and a fiber length of 70 mm was used.

(High strength fiber)
As high-strength fibers, para-aramid fibers “Technora” (trade name) (aramid fibers) manufactured by Teijin Limited having a fineness of 1.7 dtex and a fiber length of 50 mm were used. The tensile elastic modulus according to JIS L 1013 is 33 GPa.

(Thermoplastic fiber)
<Polypropylene fiber>
As a thermoplastic resin fiber, a resin fiber (polyolefin resin fiber) having a fineness of 6.6 dtex and a fiber length of 51 mm obtained by melt spinning a polypropylene resin “Novatec SA01” (trade name) manufactured by Nippon Polypro Co., Ltd. was used.

<Acid-modified polypropylene fiber>
The thermoplastic resin fiber was obtained by dry blending 95% by mass of the above polypropylene resin and 5% by mass of maleic anhydride-modified polypropylene resin “Modic P908” (trade name) manufactured by Mitsubishi Chemical Corporation, and then melt spinning. Resin fibers (acid-modified polyolefin resin fibers) having a fineness of 6.6 dtex and a fiber length of 51 mm were used.

(Intermediate film)
As the intermediate film, a three-layer film (total thickness: 95 μm) including a core layer made of polyamide and a pair of adhesive layers made of polyethylene laminated on both sides thereof was used. In the three-layer film, a plurality of through holes having a diameter of 0.5 mm are formed at regular intervals of 3 mm.

[2. Production of multi-layer fiber-containing resin molding 1]
Example 1
600 parts by mass of kenaf fibers and 600 parts by mass of acid-modified polyolefin resin fibers (acid-modified PP fibers) were laminated by a card machine to prepare a fiber assembly for a base material layer. Separately, 150 parts by mass of kenaf fiber, 60 parts by mass of polypropylene fiber (PP fiber), and 90 parts by mass of high-strength fiber are laminated by a card machine, and a fiber assembly for a shock absorbing layer. Was made. And the said intermediate | middle film was mounted on the fiber assembly for base material layers, and also the fiber assembly for shock absorption layers was mounted on it. The multilayer fiber assembly thus obtained was heated and compressed (235 ° C., 60 seconds) with a hot plate press to obtain a mat. Subsequently, a cooling press is performed on the mat for 60 seconds, and then the temperature is set to 25 ° C., the size is 100 mm × 100 mm × 2.5 mm, and the basis weight is 1500 g / m ^2. A contained resin molded body (board) was obtained. The impact absorbing layer of the multilayer fiber-containing resin molded body has a thickness (d1) of 0.5 mm and a basis weight of 300 g / m ² . The base material layer of the multilayer fiber-containing resin molded body has a thickness (d2) of 2 mm and a basis weight of 1200 g / m ² .

(Example 2)
A multilayer fiber-containing resin molded article of Example 2 in the same manner as in Example 1, except that no intermediate film is interposed between the fiber aggregate for the base material layer and the fiber aggregate for the shock absorbing layer. (Board) was produced.

Example 3
In the same manner as in Example 2, except that 60 parts by mass of acid-modified polyolefin resin fiber (acid-modified PP fiber) was used instead of polypropylene fiber when forming the fiber structure for impact absorption. The multilayer fiber-containing resin molded body (board) of Example 3 was produced.

(Comparative Example 1)
Except for changing the blending amount of polypropylene fibers to 90 parts by mass and changing the blending amount of high-strength fibers to 60 parts by mass when forming the fiber aggregate for impact absorption, the same as in Example 2. A multilayer fiber-containing resin molded body (board) of Comparative Example 1 was produced.

(Comparative Example 2)
In the same manner as in Comparative Example 1, except that 90 parts by mass of acid-modified polyolefin resin fiber (acid-modified PP fiber) was used instead of polypropylene fiber when forming the fiber structure for impact absorption. The multilayer fiber-containing resin molded body (board) of Example 2 was produced.

(Comparative Example 3)
Except for changing the blending amount of the polypropylene fiber to 105 parts by mass and changing the blending amount of the high-strength fiber to 45 parts by mass when forming the fiber aggregate for impact absorption, the same as in Example 2. A multilayer fiber-containing resin molded body (board) of Comparative Example 3 was produced.

(Comparative Example 4)
In the same manner as in Comparative Example 3, except that 105 parts by mass of acid-modified polyolefin resin fiber (acid-modified PP fiber) was used instead of polypropylene fiber when forming a fiber structure for impact absorption. The multilayer fiber-containing resin molded body (board) of Example 4 was produced.

(Comparative Example 5)
637.5 parts by mass of kenaf fiber, 637.5 parts by mass of acid-modified polyolefin resin fiber (acid-modified PP fiber), and 225 parts by mass of high-strength fiber are laminated by a card machine to produce a fiber assembly. did. The fiber assembly was heated and compressed (235 ° C., 60 seconds) by a hot plate press to obtain a mat. Subsequently, the mat was subjected to a cooling press for 60 seconds, and then the temperature was set to 25 ° C., the size was 100 mm × 100 mm × 2.5 mm, and the basis weight was 1500 g / m ^2. A mold fiber-containing resin molded body (board) was obtained.

(Comparative Example 6)
When the fiber aggregate is formed, comparison is made except that the blending amount of the kenaf fiber is changed to 750 parts by mass, the blending amount of the acid-modified polyolefin resin fiber is changed to 750 parts by mass, and the high-strength fiber is not blended. In the same manner as in Example 5, a single-layer fiber-containing resin molded body (board) of Comparative Example 6 was obtained.

(Examples 4 to 6 and Comparative Examples 7 and 8)
Except having used each raw material with the compounding quantity shown by Table 2, it carried out similarly to the said Example, and produced the multilayer type fiber containing resin molding (board) of Examples 4-6 and Comparative Examples 7 and 8. FIG. .

[3. Evaluation)
The test shown below was done about each board obtained in Examples 1-3 and Comparative Examples 1-8.

(Puncture impact test)
In accordance with JIS K7211-2: 2006, the maximum impact force (kN) and puncture energy absorption of each board using a high-speed impact tester (product name “Hydroshot HITS-P10”, manufactured by Shimadzu Corporation) (J) and the puncture displacement (mm) were measured. The measurement results of Examples 1 to 3 and Comparative Examples 1 to 6 are shown in Table 1. In addition, about the measurement result of the puncture energy absorption amount (J) and puncture displacement amount (mm) of Examples 1-3 and Comparative Examples 1-6, it showed also in FIG. 4 (graph). The measurement results of Examples 4 to 6 and Comparative Examples 7 and 8 are shown in Table 2.
The measurement conditions are as follows.
Inner diameter of support base: 40mm
Striker shape: spherical with a diameter of 20 mm Impact velocity: 4.4 m / sec

  In the multilayer fiber-containing resin molded bodies of Examples 1 to 3, the ratio of the thickness (d1) of the shock absorbing layer to the total thickness (d1 + d2) of the thickness (d1) of the shock absorbing layer and the thickness (d2) of the base material layer This is a case where (d1 / (d1 + d2)) is 0.2. That is, it is a case where 20% (or about 20%) of the thickness of the multilayer fiber-containing resin molded body is made of an impact absorbing layer. Moreover, in Examples 1-3, the content rate of a high strength fiber is 30 mass% in the impact-absorbing layer which has such thickness. The multilayer type fiber-containing resin molded bodies of Examples 1 to 3 have a puncture energy absorption amount of 5.0 J or more in the puncture impact test, and it was confirmed that they have excellent impact resistance performance. Moreover, it was confirmed that the multilayer type fiber-containing resin molded bodies of Examples 1 to 3 have a large puncture displacement amount and are difficult to break. In addition, it was confirmed that the multilayer fiber-containing resin molded bodies of Examples 1 to 3 had a maximum impact force of 0.49 kN or more and had excellent rigidity.

  Comparative Examples 1 to 4 are cases in which the impact absorbing layer having the same thickness as that of Example 1 and the like is provided, but the content of high-strength fibers contained in those impact absorbing layers is small. Specifically, the content of Comparative Examples 1 and 2 is 20% by mass, and the content of Comparative Examples 3 and 4 is 15% by mass. In Comparative Examples 1 to 4, the puncture energy absorption amount in the puncture impact test was 3.70 to 4.72 J, and the impact resistance performance was insufficient.

  Comparative Examples 5 and 6 are single-layer fiber-containing resin molded bodies, and the thicknesses thereof are the same (or substantially the same) as the multilayer-type fiber-containing resin molded bodies of Example 1 and the like. Comparative Example 5 is a case where high strength fibers are included, and Comparative Example 6 is a case where high strength fibers are not included. In Comparative Example 5, high-strength fibers having a mass ratio of 2.5 times (225/90 times) are used as compared with Example 1 and the like. As in Comparative Example 5, the amount of puncture energy absorbed in the puncture impact test remained at 4.20 J even when much higher strength fibers were used than in Example 1 or the like. On the other hand, in Example 1 etc. which were mentioned above, even if it is a small quantity of high strength fibers, the impact-resistant performance is efficiently obtained by concentrating the high strength fibers in the impact absorbing layer. Moreover, in the comparative example 6 which does not contain a high strength fiber, the amount of puncture energy absorption was 2.87J, and the impact resistance performance was remarkably low.

  In Examples 4 and 5, the total thickness (d1 + d2) of the thickness (d1) of the shock absorbing layer and the thickness (d2) of the base material layer is the same as that of Example 1 or the like, but the thickness of the shock absorbing layer ( This is a case where d1) is smaller than that of Example 1 or the like. Specifically, the thickness (d1) of the impact absorbing layer of Examples 4 and 5 is 0.25 mm, and occupies 10% of the thickness of the multilayer fiber-containing resin molded body. In Examples 4 and 5, although the thickness (d1) of the shock absorbing layer is small, the content of high-strength fibers in the shock absorbing layer is higher than that in Example 1 and is 40% by mass. Also in Examples 4 and 5, the puncture energy absorption amount was 5.0 J or more, and it was confirmed that high impact resistance performance was provided.

  In Comparative Example 7, the thickness (d1) of the shock absorbing layer is the same as that of Examples 4 and 5, but the content of high-strength fibers in the shock absorbing layer is set lower than in Examples 4 and 5. (Content: 30% by mass). In Comparative Example 7 as described above, the puncture energy absorption amount was low, and the impact resistance performance was insufficient.

  In Example 6, the total thickness (d1 + d2) of the thickness (d1) of the shock absorbing layer and the thickness (d2) of the base material layer is the same as in Example 1 and the like, but the thickness (d1) of the shock absorbing layer. Is larger than that of Example 1 or the like. Specifically, the thickness (d1) of the shock absorbing layer of Example 6 is 0.5 mm, and occupies 50% of the thickness of the multilayer fiber-containing resin molded body. In addition, the content rate of the high strength fiber in the impact-absorbing layer of Example 6 is the same as Example 1 etc., and is set to 30 mass%. Also in Example 6 as described above, the puncture energy absorption amount was 5.0 J or more, and it was confirmed that high impact resistance performance was provided.

  In Comparative Example 8, the thickness (d1) of the shock absorbing layer is the same as that of Example 6, but the content of the high strength fibers in the shock absorbing layer is set lower than that of Example 6 (content: 12% by mass). In such Comparative Example 8, the amount of puncture energy absorbed was low, and the impact resistance performance was insufficient.

  Here, for Examples 1 to 5, Comparative Examples 1 to 4 and Comparative Examples 7 and 8 described above, d1 / (d1 + d2), high-strength fiber content (% by mass), puncture energy absorption amount (J) The relationships are summarized in Table 3.

  As shown in Table 3, the amount of puncture energy absorbed is adjusted by appropriately adjusting the ratio (d1 / (d1 + d2)) relating to the thickness d1 of the shock absorbing layer and the content of high-strength fibers in the shock absorbing layer. Was found to be able to be set to 5.0 J or more, and it was confirmed that a multilayer fiber-containing resin molded article excellent in impact resistance performance was obtained. In Table 3, the symbol “◯” indicates the case where the puncture energy absorption amount is expected to be 5.0 J or more although the puncture impact test is not performed. In Table 3, the symbol “x” indicates a case where the puncture energy absorption amount is expected to be less than 5.0 J although the puncture impact test is not performed.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

  (1) The multilayer fiber-containing resin molded body of the above embodiment is widely used in the fields of vehicles, ships, aircraft, architecture, etc., and is suitably used as an interior material, exterior material, structural material, etc. in these fields. In the field of vehicles, for automobiles, door base material, package tray, pillar garnish, switch base, quarter panel, armrest core material, door trim, seat structure material, console box, dashboard, various instrument panels, deck trim, Examples include bumpers, spoilers, and cowlings. Furthermore, it is also suitable for interior materials, exterior materials and structural materials such as buildings and furniture. Specifically, door cover materials, door structure materials, cover materials for various furniture (desks, chairs, shelves, bags, etc.), structural materials, and the like can be given. In addition, it is also suitable as a package, a container (such as a tray), a protective member, and a partition member.

  DESCRIPTION OF SYMBOLS 1,1A ... Multilayer type fiber-containing resin molding, 2 ... Base material layer, 3 ... Shock absorption layer, 4 ... Intermediate film, 40 ... Core layer, 41, 42 ... Adhesive layer

Claims (5)

A base material layer containing a thermoplastic resin and plant fibers;
A multilayer-type fiber-containing resin molded body comprising a thermoplastic resin, plant fibers, and high-strength fibers, and an impact absorbing layer laminated on one surface side of the base material layer. The content of the high-strength fiber in the shock absorbing layer is 25% by mass or more,
The ratio (d1 / (d1 + d2)) of the thickness (d1) of the shock absorbing layer to the total thickness (d1 + d2) of the thickness (d1) of the shock absorbing layer and the thickness (d2) of the base material layer is 0.1 or more. And
The multilayer type fiber-containing resin molded article according to claim 1, wherein the puncture energy absorption amount in a puncture impact test based on JIS K7211-2: 2006 is 5.0 J or more. The thermoplastic resin of the base material layer is made of a polyolefin resin,
The thermoplastic resin of the shock absorbing layer is made of a polyolefin resin,
The multilayer fiber-containing resin molded product according to claim 1 or 2, wherein the impact absorbing layer has an acid-modified polyolefin resin content of 1.2 mass% or less.   The core layer and a pair of adhesive layers respectively laminated on both sides of the core layer, and comprising an intermediate film interposed between the base material layer and the shock absorbing layer. The multilayer-type fiber-containing resin molded product according to any one of the above.   The multi-layer fiber-containing resin molded body according to any one of claims 1 to 4, wherein the tensile elastic modulus of the high strength fiber is 27 GPa or more.

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