JP5560034B2 - Lightweight automotive interior parts - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a lightweight automobile interior part, and more specifically, an instrument panel / console made of a polyolefin resin to which organic long fibers are added, and emphasizes low temperature impact characteristics and high temperature rigidity required for automobile parts. It relates to lightweight automotive interior parts with high appearance, molded into boxes, pillars, trims, etc.

  Conventionally, as a structural material for automobile instrument panels and safety-compliant interior materials, a rubber component and talc are blended in a propylene resin, and the former provides impact resistance and the latter imparts rigidity ( Patent References 1 to 6). According to this method, since the raw material is relatively inexpensive, there are advantages such as that the manufactured product is also inexpensive, can be ductile fractured under normal temperature use conditions, and can obtain a good molded article appearance. Many interior parts made of molding materials are used.

  In recent years, reducing carbon dioxide emissions by reducing the weight of automobiles as a measure against global warming has become an important issue, and weight reduction of resin parts for automobile interiors represented by the above is being demanded. The goal of weight reduction is to reduce the weight of a single component. Generally, this can be achieved by reducing the thickness of the component and reducing the specific gravity of the resin material used. In resin materials consisting of components and talc components, problems such as reduced rigidity of parts, impact resistance, and deterioration of flow mark appearance due to the occurrence of tiger stripe-like flow patterns (called flow marks) on the surface occur due to weight reduction. It was very difficult to solve the problem.

  For example, if the part thickness is reduced, the rigidity will decrease, so the amount of talc for rigidity reinforcement will increase, but the impact and flow mark appearance performance will decrease, and the material specific gravity will increase and the weight will be reduced sufficiently. There is a problem that cannot be achieved. In addition, when the rubber component that causes a decrease in rigidity is reduced, the impact property is naturally reduced, and there is a problem in that fragments are scattered due to brittle fracture in a component test at a low temperature.

In addition, in order to increase the rigidity relatively easily, addition of a filler having a high aspect ratio such as glass fiber or mica has been studied (see, for example, Patent Document 7). Glass fiber floats on the surface, and smooth appearance performance cannot be obtained with mirror-finished parts. Also, with grain-finished parts, the texture transfer is impaired, the texture of the texture is inferior, and the glass fiber is rigid. Are oriented in the flow direction of the molded product, and a significant warpage due to anisotropy occurs. In addition, since the stretchability of the parts is suppressed, the impact strength is reduced (brittle fracture phenomenon). In the case of mica, the anisotropy is small, but the light reflection of mica existing on the surface of the part causes a glittering feeling and the appearance performance as a design part is deteriorated, and the impact performance is reduced as in the case of glass. Occurs.
Therefore, the present applicant has proposed a composition for automobile interior parts in which organic long fibers are blended with a propylene resin (see Patent Document 8). As a result, it was possible to suppress deterioration in appearance performance (flow mark appearance and sparkling foreign object feeling) and impact performance. However, if organic long fibers are blended in a larger amount than propylene-based resin, it becomes difficult to mold thin and lightweight parts, and organic long fibers float on the surface of the parts, and smooth appearance performance cannot be obtained. There is a problem in that the textured finish of the textured parts also deteriorates.

  Under these circumstances, with the increase in demand for lightweight automobiles, development of lightweight automobile interior parts having both mechanical properties such as rigidity and impact and appearance performance has been desired.

JP 51-136735 A JP 58-1111846 JP-A-58-129037 JP 61-187859 A No. 60-3420 JP-A-3-250040 JP-A-62-36428 JP 2009-132772 A

  An object of the present invention is an instrument panel, console box, which is made of a polyolefin resin to which organic long fibers are added in view of the problems of the prior art, and emphasizes low temperature impact characteristics and high temperature rigidity required for automobile parts. It is to provide lightweight automotive interior parts with high appearance, molded into pillars and trims.

  As a result of diligent research to solve the above-described problems of the prior art, the present inventors have used a fiber-reinforced polyolefin resin material containing a specific amount of organic long fibers for a propylene resin, and at the time of injection molding. By optimizing the part thickness, lightweight automotive interior parts that combine mechanical properties such as rigidity and impact and various appearance performance (performance that does not stand out, such as flow marks, fiber floating, and glitter) can be obtained. As a result, the present invention has been completed.

That is, according to 1st invention of this invention, 5-60 weight part of organic long fibers (B) whose tensile strength is 5 cN / dtex or more are contained with respect to 100 weight part of propylene-type resin (A). A method for manufacturing a lightweight automotive interior part in which a fiber-reinforced propylene-based resin material is heated to a molten resin temperature and supplied into a mold having an inner surface formed into a predetermined shape, and injection molded ,
The injection molding is performed by setting the mold temperature to 30 to 50 ° C., the injection pressure to 40 to 100 MPa, and the injection speed to 50 to 200 mm / sec. Provided is a method for manufacturing a lightweight automobile interior part , characterized in that the surface density (product of the material density and the average thickness of the part design plane part) is less than 2 kg / m ² .

According to a second invention of the present invention, in the first invention, the fiber-reinforced propylene-based resin material is characterized in that the organic long fiber (B) is a polyester fiber and / or a polyamide fiber. A method for manufacturing an automotive interior part is provided.
According to the third invention of the present invention, in the first or second invention, the fiber-reinforced propylene-based resin material further includes an inorganic filler (C) with respect to 100 parts by weight of the propylene-based resin (A). There is provided a method for producing a lightweight automobile interior part , comprising 0 to 30 parts by weight and / or 0 to 30 parts by weight of a thermoplastic elastomer (D).
According to a fourth invention of the present invention, in any one of the first to third inventions, the fiber-reinforced propylene-based resin material has a weight of scattered pieces after the test in a product impact test at a low temperature. Provided is a method for manufacturing a lightweight automotive interior part , characterized in that it is less than 10% by weight of the pre-test product weight.
According to a fifth invention of the present invention, in any one of the first to fourth inventions, the fiber-reinforced propylene-based resin material has a tensile elastic modulus in accordance with JIS-K7161 at 80 ° C. of 1000 Mpa. Thus, there is provided a method for manufacturing a lightweight automobile interior part characterized in that broken pieces are not scattered in a part impact test at a low temperature.
According to the sixth invention of the present invention, in any one of the first to fifth inventions, the propylene-based resin (A) is melt flow rate (according to JIS K7210, temperature 230 ° C., load 21.18 N). in the manufacturing method of light-weight automotive interior parts, characterized in that the measured value) is 60 g / 10 minutes or more is provided.
According to the seventh invention of the present invention, in any one of the first to sixth inventions, the organic long fiber (B) has a crystal melting point (a softening point when no melting point is observed) is 200 ° C. or higher, or There is provided a method for manufacturing a lightweight automotive interior part characterized by being not thermoplastic.

The lightweight automotive interior part of the present invention (hereinafter sometimes abbreviated as “fiber-reinforced lightweight part”) contains a specific amount of organic long fibers (B) in a propylene-based resin (A), and has an average surface density of a flat portion. Is less than 2 kg / m ^2, and the reinforcing effect is improved by dispersing the long fibers in a network, and the interfacial adhesion between the fibers and the propylene-based resin as a matrix is moderately adjusted. Lightweight that cannot be achieved with a product can be obtained, and balance with mechanical properties such as impact resistance and heat rigidity can be easily achieved.
Moreover, when the average surface density of the plane is less than 2 kg / m ² , the thickness of the part can be designed to be thin (thinning). Improving the mold internal pressure at the time of injection molding, the organic long fibers (B) are pressed into the matrix resin on the mold surface and thinned, so the interface between the organic long fibers (B) and the matrix resin becomes close, It is possible to prevent a poor appearance called fiber surface floating, which has been a problem with conventional fiber-based resins, and achieve a high appearance. In addition, when the thickness of the part is designed to be thick so that the average surface density of the plane is less than 2 kg / m ² , the concentration of the organic long fiber can be lowered, so that the fiber floating is reduced. The appearance performance is maintained and improved.

  Furthermore, the fiber-reinforced lightweight part of the present invention has a feature of higher heat resistance rigidity (rigidity at high temperature) than a lightweight part designed by blending a large amount of conventionally known rubber components, talc, and the like. In addition, when the impact is applied to the component at low temperature and the fracture occurs, the propagation of the fracture from the fracture point is suppressed by the fiber, so there is no scattering of the component and the fracture surface is not easily sharpened. Even if there is a human body in the vicinity, secondary damage such as cuts will not occur.

It is the schematic explaining the manufacturing process of the organic long fiber reinforced polyolefin resin molding material pellet used by this invention.

Below, the lightweight automotive interior component of the present invention will be described in detail.
A lightweight automobile interior part of the present invention is an automobile injection-molded with a fiber-reinforced propylene resin material containing 5 to 60 parts by weight of an organic long fiber (B) with respect to 100 parts by weight of a propylene resin (A). An interior part for a vehicle, wherein an average surface density (product of a material density and an average thickness of a part design plane part) formed by a fiber-reinforced propylene resin material is less than 2 kg / m ^2. .

1. Fiber Reinforced Polyolefin Resin Material The fiber reinforced propylene resin material used in the present invention contains 5-60 parts by weight of organic long fiber (B) with respect to 100 parts by weight of propylene resin (A). It is a resin material.

(1) Propylene resin (A)
The propylene-based resin (A) is not particularly limited, and examples thereof include a propylene homopolymer, propylene-based ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, and the like. And other α-olefin copolymers with one or more. The copolymer may be a random copolymer or a block copolymer, but is preferably a block copolymer having an excellent balance between rigidity and impact property. In addition, said "main component" refers to what is contained in a propylene-type resin 50weight% or more, Preferably it is 60weight% or more.

The propylene-based resin (A) can be obtained by polymerizing propylene and, if necessary, α-olefin in the presence of a propylene polymerization catalyst. Any polymerization method may be employed as long as a resinous material can be obtained, but a gas phase method or a solution method is particularly preferable.
The melt flow rate of the propylene-based resin is based on JIS K7210, and the value measured at a temperature of 230 ° C. and a load of 21.18 N is usually 10 to 200 g / 10 minutes, preferably 30 to 150 g / 10 minutes, more preferably 60-150 g / 10 min. If the melt flow rate is in this range, the moldability does not deteriorate, the flow mark appearance on the surface of the resulting molded article becomes good, and a lightweight part with a high appearance can be obtained. In addition, the mechanical strength of the molded product does not decrease, and the dispersion of the organic long fibers (B) does not easily become defective, so that the fracture performance in the impact test of the parts is improved.

In the fiber-reinforced lightweight part of the present invention, the propylene-based resin (A) may be used alone or in combination of two or more. Further, in the present invention, as the propylene resin (A), for example, an acid-modified propylene resin modified with maleic anhydride can be added.
Examples of the acid-modified olefin resin include (a) an olefin homopolymer or a copolymer of two or more olefins, for example, a polyolefin obtained by graft polymerization of an unsaturated carboxylic acid or a derivative thereof, and (b) a polyolefin. (C) A copolymer obtained by copolymerizing one or two or more olefins and one or two or more unsaturated carboxylic acids or derivatives thereof, which is a polymerization raw material monomer of (c). Examples include those obtained by graft polymerization of saturated carboxylic acids or derivatives thereof.
However, the addition amount is preferably small. Moreover, although the organic long fiber (B) mentioned later can be surface-treated, it is preferable not to use acid-modified olefin resin. By satisfying such conditions, the interfacial strength between the propylene-based resin (A) as the matrix resin and the organic long fiber (B) can be weakened, and the tensile elongation at break and impact resistance can be further enhanced. This is because the scattering of parts during the impact test can be suppressed.

(2) Organic long fiber (B)
The organic long fibers (B) used in the present invention include, for example, polyester fibers (typical example polyethylene terephthalate; melting point about 260 ° C. thermoplastic), polyamide fibers (typical example nylon 6-6; melting point about 268 ° C. thermoplastic), polyurethane fibers (Typical example spandex; melting point 200-230 ° C. thermoplastic), acrylic fiber (typical example polyacrylonitrile; melting point about 317 ° C. thermoplastic), vinylon fiber (typical example vinylon; softening point 220-230 ° C.), kenaf fiber (typical example) It can be selected from natural fibers such as horse hemp; decomposition point 200 ° C. natural fiber not thermoplastic. Of these, polyester fibers or polyamide fibers are preferred in consideration of raw material costs. A plurality of types may be selected and mixed for use.
The organic long fiber has a melting point (softening point for those having no melting point) of 200 ° C. or higher, preferably 230 ° C. or higher, more preferably 240 ° C. or higher, or a material that does not melt plasticize even when heated. Is preferred. This is because it is preferable that the organic long fiber is not melt-plasticized and dispersed as a fibrous filler during the molding process. Here, the melting point is a value determined by DSC measurement. When the melting point is not observed by DSC measurement, the softening point (Vicat softening point) is preferably 200 ° C. or higher.

  The length of the organic long fiber is 4 to 20 mm, and 4 to 10 mm is particularly preferable. If the length of the organic long fiber is within this range, the fibers dispersed in the molded product are entangled with each other, and as a result, the molded product exhibits sufficient impact resistance. Moreover, it is because the pellet as a forming raw material does not become too enlarged or the aspect ratio becomes too large, and can be stably and continuously supplied to the molding machine.

  The tensile strength of the organic long fibers is not particularly limited, but those having a value measured in accordance with JIS L1013 of 3 cN / dtex or more, particularly 5 cN / dtex or more are suitable. If the tensile strength is within this range, the fiber does not stretch or break when plasticizing the pellets in the molding machine cylinder, and when the resulting molded product is impacted and broken, the fiber breaks and pulls. Since it does not occur preferentially, the molded article can exhibit sufficient impact resistance. The tensile strength of the organic long fiber is preferably 50 cN / dtex or less, more preferably 30 cN / dtex or less, and particularly preferably 10 cN / dtex or less. As the high-strength organic fibers, those generally marketed for applications such as tire cords, tents, sheets, and concrete reinforcing fibers can be suitably used.

  In particular, some organic fibers for tire cords have a polar resin attached for the purpose of improving adhesion to a rubber matrix. For example, there are proposed ones in which an epoxy resin is attached to an organic fiber, and rubber latex or an isocyanate compound is further attached to the fiber (Japanese Patent Laid-Open Nos. 7-3566, 8-13346, Open 2001-19927 etc.). In the present invention, an organic fiber to which such a polar resin is attached can also be suitably used.

  In the present invention, conventionally known components such as thermoplastic elastomers, inorganic fillers such as talc, polar group modifiers, additives and the like can be blended for the purpose of improving the performance balance without impairing the object of the present invention.

(3) Inorganic filler (C)
The inorganic filler (C) that can be used in the present invention can be added mainly for the purpose of adjusting the rigidity of the component, and examples thereof include talc, wollastonite, calcium carbonate, barium sulfate, and whiskers.
In the case of talc, those having an average particle size of usually 15 μm or less, preferably 12 μm or less, more preferably 10 μm or less are preferred. If the average particle size is within this range, the impact resistance of the parts is not lowered. Moreover, talc itself is not too expensive, and further, the fluidity of the molding material is not significantly reduced. Here, the average particle diameter is a particle diameter value of a cumulative amount of 50% by weight measured by a liquid phase precipitation type light transmission method and read from a particle size cumulative distribution curve. The talc having an average particle diameter as described above is generally produced by dry classification after dry pulverization.

The specific surface area of talc is usually 1.5 m ² / g or more, preferably 2.0 m ² / g or more, more preferably 3.0 m ² / g or more. If the specific surface area is within this range, the impact resistance of the component does not tend to be insufficient. Further, talc itself is not expensive, and the fluidity of the molding material is not significantly reduced. The specific surface area here is a value measured by an air permeation method.

(4) Thermoplastic elastomer (D)
The thermoplastic elastomer (D) that can be used in the present invention can be added mainly for the purpose of adjusting the impact properties of the parts.
Specifically, ethylene-propylene elastomer, ethylene-butene-1 elastomer, ethylene-octene-1 elastomer, ethylene-propylene-diene elastomer, polybutadiene, styrene-diene copolymer, acrylonitrile-butadiene copolymer, polyisoprene, etc. And diene rubber, styrene-butadiene block copolymer, hydrogenated styrene-butadiene block copolymer, ethylene ionomer resin, hydrogenated styrene-isoprene block copolymer, and the like. These thermoplastic elastomers can be used alone or in combination of two or more.

(5) Mixing ratio of each component The fiber-reinforced polyolefin resin material used in the present invention contains a propylene resin (A) and an organic long fiber (B) as essential components, and 100 parts by weight of the propylene resin. The ratio of the organic long fiber (B) is 5 to 60 parts by weight, preferably 10 to 50 parts by weight, more preferably 15 to 45 parts by weight.
If the ratio of the organic long fiber (B) is 5 parts by weight or more, the reinforcing effect tends to be sufficiently large, and if it is within 60 parts by weight, the average surface density of the flat part (material density and part design flat part average) It is easy to mold a light-weight part having a product (thickness product) of less than 2 kg / m ² , and the appearance of the part (fiber floating) tends to be improved.

In the present invention, when talc (C) is added to the fiber-reinforced polyolefin resin material, the ratio is 0 to 30 parts by weight, preferably 5 to 25 parts by weight, more preferably as a ratio with respect to 100 parts by weight of the propylene resin. 10 to 20 parts by weight. If the ratio of talc is within 30 parts by weight, the surface density of the parts is not increased and the weight can be easily reduced, and the fluidity is not lowered and the molding is facilitated. In addition, the flow mark appearance tends to be improved, and a tiger-striped flow pattern is unlikely to occur.
In the present invention, when the thermoplastic elastomer (D) is added to the fiber reinforced polyolefin resin material, the ratio is 0 to 30 parts by weight, preferably 5 to 25 parts by weight, as a ratio to 100 parts by weight of the propylene resin. Preferably it is 10-20 weight part. If the ratio of the thermoplastic elastomer is within 30 parts by weight, the rigidity of the parts does not decrease and the rigidity can be easily maintained at a high temperature.

In addition to the propylene-based resin (A), an inorganic filler (C) and a thermoplastic elastomer (D) can be added as necessary. In addition, in order to impart desired characteristics depending on the purpose, the thermoplastic resin is generally used. Known substances to be added, for example, stabilizers such as antioxidants, heat stabilizers, UV absorbers, antistatic agents, flame retardants, flame retardant aids, colorants (dyes and pigments), lubricants, plasticizers Further, a crystallization accelerator, a crystal nucleating agent and the like can be further blended.
The fiber-reinforced polyolefin resin material used in the present invention has a molded product weight after the test of 90% or more, preferably 95% or more, based on the molded product weight before the test in a product impact test at a low temperature. It is desirable that the weight ratio of the scattered pieces is small. This is because the proportion of human damage at the time of component destruction increases as the weight proportion of scattered pieces increases. Further, it is desirable that this fiber-reinforced polyolefin resin material has a tensile modulus of 80 ° C. or more in accordance with JIS-K7161 of 1000 Mpa or more and that no debris is scattered in a component impact test at a low temperature. Within this range, it is easy to suppress deflection and deformation of parts exposed to high temperatures such as instrument panel peripheral parts. And a thin fiber reinforced lightweight part can be easily shape | molded with the fiber reinforced polyolefin resin material which satisfy | fills such conditions.

(6) Organic long fiber reinforced polyolefin resin molding material pellets In the present invention, the fiber reinforced polyolefin resin material contains 5 to 60 parts by weight of organic long fiber (B) with respect to 100 parts by weight of propylene resin (A). The resulting fiber reinforced resin material is used as an organic long fiber reinforced polyolefin resin molding material pellet (hereinafter also simply referred to as a resin molding material pellet) for molding fiber reinforced lightweight parts.

The resin molding material pellet is obtained by a method (pulling molding method) in which continuous organic long fibers (B) are drawn from a fiber rack through a crosshead die and impregnated with a molten resin containing a propylene-based resin (A). Specifically, as shown in FIG. 1, the fiber is supplied from the fiber rack 1 to the extruder 2 as a fiber bundle and passed through a cross head (resin impregnation die 3) attached to the tip of the extruder 2. Resin is supplied to the crosshead and impregnated. Thereafter, the fiber bundle impregnated with the resin is cooled in the water tank 4, sent to the cutter 6 by the take-up machine 5, and becomes pellets 7.
That is, for example, a resin additive is added to the propylene resin (A) as necessary, and the propylene resin (A) is melted from the extruder while the organic long fiber (B) is drawn through a crosshead die. It is supplied to the crosshead die, the organic long fiber (B) is impregnated with the propylene resin (A), the melted impregnated product is heated, cooled, and then cut at right angles to the drawing direction. According to this method, organic long fiber reinforced polyolefin resin molding in which organic long fibers (B) are arranged in parallel in the length direction of the obtained pellets without causing damage to the organic long fibers (B). Material pellets are obtained.

  The pultrusion method is basically a method of impregnating a resin while drawing a continuous reinforcing fiber bundle. In the embodiment, as a typical pultrusion method, as shown in FIG. 1, a method of supplying and impregnating a resin to the crosshead from an extruder or the like while passing the fiber bundle through the crosshead can be mentioned. In addition, the fiber bundle is impregnated through an impregnation bath containing a resin emulsion, suspension or solution, resin powder is sprayed onto the fiber bundle or resin is applied to the fiber through the fiber bundle in a tank containing the powder. A method of melting and impregnating a resin after attaching a powder is known. Any aspect can be used in the present invention, but the crosshead method is particularly preferable. Further, the resin impregnation operation in these pultrusion methods is generally performed in one stage, but may be divided into two or more stages, and may be performed by different impregnation methods. FIG. 1 shows a state in which four fibers are supplied to the extruder 2 as a fiber bundle, but the number of fibers is not particularly limited, and is about 2 to 10, preferably 3 to 8, depending on the application. Can be changed.

  When producing pellets containing organic long fibers, it is preferable that they are combined with an olefin resin at a processing temperature such that the organic long fibers are not melt plasticized. The processing temperature is preferably 160 ° C. or higher at the site where the organic long fibers are provided. The upper limit of the processing temperature is 20 ° C. or lower when the melting point (softening point for those having no melting point) of 320 ° C. or lower, and the melting point is 320 ° C. or higher; When it is not melt plasticized even when heated, the temperature is preferably 300 ° C. or lower. Regardless of which organic long fiber is selected, as long as the pellet processing temperature is within 300 ° C., the olefin resin is not significantly degraded by thermal decomposition, and there is no fear of ignition or ignition.

  The melt impregnated product is extruded to a strand after the heating reaction, cooled to a temperature capable of being cut, and cut by a cutter into pellets. Examples of the shape of the pellet include a columnar shape, a prismatic shape, a plate shape, and a die shape. In the pellets thus obtained, the organic long fibers (B) have substantially the same length, and the direction of each fiber is aligned in the extruded direction (that is, the length direction of the pellet). Further, the above pellets may be those using two or more types of organic long fibers having different types and concentrations, and those using a mixture of propylene resins.

  In the above-described pultrusion method, the resin molding material pellets are obtained by arranging organic long fibers (B) in parallel with the same length in the length direction of the pellets. Compound pellets dispersed so as to be entangled randomly may be used. In the present invention, the “pellet” is used in a broad sense including a strand shape, a sheet shape, a flat plate shape and the like in addition to the above-mentioned narrowly defined pellets.

  The dimension of the organic long fiber reinforced polyolefin resin molding material pellet used for the fiber reinforced lightweight part of the present invention is usually 4 to 50 mm, preferably 4 to 20 mm, more preferably 4 to 10 mm. If the length of the organic long fiber (B) in the pellet is within this range, sufficient component performance can be obtained, and the pellet can be easily supplied to the injection molding machine.

2. Fiber Reinforced Lightweight Parts and Manufacturing Method The fiber reinforced lightweight parts of the present invention use the fiber reinforced polyolefin-based resin material pellets obtained as described above, and the average surface density (material density) of the planar portion of the automotive interior parts. And the product of the average thickness of the part design plane part) is injection-molded so as to be less than 2 kg / m ² .

Here, the average surface density of the plane portion is determined by the product of the material density (density of the fiber-reinforced polyolefin resin material) and the average thickness of the part design plane portion (the plane portion on the side subjected to embossing). It is
This average surface density is less than 2 kg / m ² , preferably 1.9 kg / m ² or less, more preferably 1.8 kg / m ² or less. If the average surface density is less than 2 kg / m ² , the floating organic long fibers are less noticeable on the component surface.
Therefore, in the automobile interior part of the present invention, the product (D × T) of the material density (D: unit g / cm ³ ) and the part thickness (T: unit mm) is 2 kg / m ² . It is preferable to set the thickness of the part in consideration of the material density. For example, when the density of a propylene resin material containing 25 parts by weight of a polyethylene terephthalate fiber in 100 parts by weight of a propylene resin is 0.98 g / cm ³ , if the thickness of the part is less than 2040 μm, the automobile interior part of the present invention Will be obtained.

The resin molding material pellets obtained as described above are used alone or diluted with another thermoplastic resin, preferably the same type of resin as the propylene resin (A), and used as a raw material for injection molding. The kind and ratio of the resin to be diluted are determined by the physical property values desired for the part.
The organic long fiber reinforced polyolefin resin molding material pellet used in the present invention is heated to a molten resin temperature and supplied at a predetermined temperature, injection pressure, and injection speed into a mold having an inner surface of a predetermined shape. The molten resin temperature is, for example, 180 to 230 ° C., although it depends on the amount of propylene resin in the molding material pellet. The mold temperature is maintained at, for example, 30 to 50 ° C., although it depends on the thickness and shape of the molded body. The injection conditions depend on the type of apparatus and the thickness and shape of the molded body, but can be, for example, an injection pressure of 40 to 100 MPa and an injection speed of 50 to 200 mm / second. As a result, the molding material pellets are injection-molded by the mold, and the molded article has good texture transferability of the mold and the fiber does not stand out. According to the present invention, since the organic long fiber reinforced polyolefin resin molding material having a specific composition is used, there is little breakage at the time of injection molding, and the organic long fibers can be uniformly dispersed inside the molded body.
In particular, if the mold internal pressure at the time of injection molding is improved to about 30 MPa, the organic long fibers (B) are pressed into the matrix resin on the mold surface and thinned, so the organic long fibers (B) and the matrix resin As a result, it is possible to prevent a defect in appearance called surface lifting of the fiber, which has been a problem with conventional fiber-based resins, and achieve high appearance performance.

In addition, if the thickness of the part is increased in a range where the average surface density of the plane is less than 2 kg / m ² , it is possible to reduce the concentration of the organic long fiber, so that the floating of the fiber is reduced and the appearance is reduced. Performance is maintained and improved.
Furthermore, the fiber-reinforced lightweight part of the present invention has higher heat-resistant rigidity (rigidity at high temperatures) than conventionally known lightweight parts containing a large amount of rubber components, talc, and the like. Therefore, the interior parts for automobiles of the present invention can use the above injection-molded body alone. In addition, when the impact is applied to the component at low temperature and the fracture occurs, the propagation of the fracture from the fracture point is suppressed by the fiber, so there is no scattering of the component and the fracture surface is not easily sharpened. Even if there is a human body in the vicinity, secondary damage such as cuts will not occur.
Furthermore, as long as the effect of the present invention is not impaired, injection is performed by adding a known chemical foaming agent (inorganic or organic chemical foaming agent) to the organic long fiber reinforced polyolefin resin molding material pellet of the present invention. It is possible to obtain a fiber-reinforced foamed lightweight part by molding. As the injection foam molding method, a short shot molding method for injecting with a small resin injection volume (measurement) or a core back molding method for retreating the mold after injection filling with a normal resin amount can be used. The latter core back molding method is preferred in that the expansion ratio can be easily improved.

  The fiber-reinforced lightweight part of the present invention can be formed into a molded body with embossed pattern (textured embossed pattern) having a surface with a raised or recessed pattern such as leather or geometric. For this purpose, it is preferable to perform various embossing processes such as etching on the design surface side of the injection mold. Also, a method of passing between a roll for embossing (embossing pattern processing) and a pressure roll such as a rubber roll in a molten state or a semi-molten state, reheating with a heating drum or an infrared heater, and a roll for embossing (embossing pattern processing) A method of passing between a metal roll and a pressure roll such as a rubber roll, a method of pressing using a mold with an embossed pattern, and vacuum forming using a male and female mold with an embossed pattern, and simultaneously embossing. (Embossed pattern processing) can also be used.

The automotive inner layer component of the present invention has an average surface density made of a fiber-reinforced propylene resin material containing 5 to 60 parts by weight of the organic long fiber (B) with respect to 100 parts by weight of the propylene resin (A). A multilayer molded body including an injection molded body of less than 2 kg / cm ² and a substrate may be used.
Examples of the polyolefin resin constituting the substrate layer include polypropylene, polyethylene, a copolymer of ethylene and propylene, and a copolymer of ethylene and / or propylene and other components. Two or more of these polyolefin resins may be contained in the base material layer. The content of the polyolefin-based resin in the base material layer is preferably higher, and is usually 50% by weight or more, preferably 80% by weight or more, and more preferably 95% by weight or more.
Moreover, a base material layer can also be used as a foam layer for the purpose of weight reduction as a laminated product.

  Examples of the automobile interior part of the present invention include an instrument panel, a door trim, a console box, a pillar, and a header trim.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited by a following example, unless the summary is exceeded. The materials and evaluation methods used in the following examples are as shown below.

<Materials used>
(1) Propylene resin (A)
A-1: Polypropylene (block copolymer, MFR (measured at a temperature of 230 ° C. and a load of 21.18 N according to JIS K7210) 100 g / 10 min)
"Novatec PP BC10AHA" manufactured by Nippon Polypro Co., Ltd.
A-2: Polypropylene (block copolymer, MFR (according to JIS K7210, measured at a temperature of 230 ° C. and a load of 21.18 N) 60 g / 10 min)
"Novatec PP BC06C" manufactured by Nippon Polypro Co., Ltd.

(2) Organic long fiber (B)
B-1: Polyester fiber (PET fiber manufactured by Teijin Fibers Limited, crystal melting point 265 ° C., single yarn fineness 6.68 dtex, tensile strength 7 cN / dtex, roving product)

(3) Inorganic filler (C)
C-1: Talc (average particle size 7.4 μm, specific surface area 7.0 m ² / g), “K-1” manufactured by Nippon Talc
C-2: Glass fiber (average fiber diameter 13 μm, length 3 mm), “T480” manufactured by Nippon Electric Glass Co., Ltd.

(4) Thermoplastic elastomer (D)
D-1: Ethylene octene-1 elastomer “ENGAGE 8200” manufactured by Dow Chemical Japan, MFR 5 g / 10 min (190 ° C., 21.18 N), density 0.87 g / cm ³

(5) Other components MH-PP: Maleic anhydride-modified polyolefin, “OREVAC CA100” manufactured by Arkema, maleic anhydride graft ratio 0.8 wt%

<Molding material production>
<Method for evaluating properties of molding material>
1. Material density In accordance with JIS-K7152-1, a multipurpose test piece was prepared using an ISO mold type A at a molten resin temperature of 200 ° C. Subsequently, the central straight part (length 8 mm) of the multipurpose test piece was cut to obtain a strip-shaped test piece, and the density was measured by an underwater substitution method in accordance with JIS-K7112.
2. Tensile modulus According to JIS-K7152-1, a multipurpose test piece was produced using an ISO mold type A at a molten resin temperature of 200 ° C. Next, the central straight part (length 8 mm) of the multipurpose test piece was cut to obtain a strip-shaped test piece, and the tensile modulus at a test temperature of 80 ° C. was measured according to JIS-K7161.
3. In-mold fluidity Using a spiral mold (width 10 mm) with a wall thickness of 2 mm, injection molding was performed at a molten resin temperature of 210 ° C., a mold temperature of 40 ° C., an injection pressure of 60 MPa, and an injection speed of 100 mm / sec. The flow length of was evaluated.

<Performance evaluation of molded products>
1. Surface Density Weight per unit area (surface density kg / m ² ) was calculated from a value obtained by multiplying the material density (g / cm ³ ) described above and the average thickness (mm) of the flat part of the molded product.
2. Appearance performance {(Floating fiber, Flow mark appearance (tiger stripe pattern))
Using a flat plate mold (width 200 mm, length 400 mm), the molten resin temperature is 210 ° C., the mold temperature is 40 ° C., the injection pressure is 60 MPa, and the injection speed is 100 mm / mm so that the thickness shown in Table 1 and Table 2 is obtained. Injection molding was performed in seconds to obtain a mirror-finished flat plate, and the determination was made according to the following evaluation criteria. (Automotive interior parts are often textured with leather or geometric shapes, but they were mirror-finished to clarify performance.)

Fiber float ○ ・ ・ ・ Fiber is almost inconspicuous △ ・ ・ ・ Fiber can be seen a little × ・ ・ ・ Fiber can be seen clearly

Flow mark appearance (tiger stripe pattern)
○ ... Not generated or noticeable.
Δ: Moderately generated but less noticeable ×: Generated and conspicuous

3. Low temperature impact (destructive scattering)
The molded product used for the appearance performance of 2 above is cut into a flat plate of 150 mm × 150 mm, and subjected to a high-speed surface impact test (penetration test with a punch) at a test temperature of −30 ° C. under the following conditions, and fracture scattering properties Was observed.
Support diameter 2 inch φ
Punch diameter 0.5 inch φ (Punch tip R 0.25 inch)
Impact speed 2.5m / sec

Scattering
○: The weight of the molded product after the test is 95% or more with respect to the weight of the molded product before the test. Δ ... The weight of the molded product after the test is 90% to less than 95% with respect to the weight of the molded product before the test. ... Molded product weight after test is less than 90% of molded product weight before test

4). Moldability The value of in-mold fluidity, which is a characteristic evaluation of the molding material, is halved, and the flow length (L / T value) per 1 mm thickness is determined. Examples 1 to 13 and Comparative Example 1 are used as the L / T value. The following judgment was performed from the flow length in the actual molded product multiplied by the thickness of ˜7.
Formability ◎ ... 500mm or more ○ ... 300-500mm
× ・ ・ ・ 300mm full

(Examples 1 to 13), (Comparative Examples 5 to 7)
Polypropylene (A-1, A-2), PET long fiber (B-1), talc (C-1), thermoplastic elastomer (D-1), and maleic acid-modified polypropylene are blended as shown in Tables 1 and 2. It was used and pultruded to produce organic long fiber reinforced polypropylene pellets. As a manufacturing apparatus, a twin screw extruder having a crosshead die (“TEX30” manufactured by Nippon Steel Works Co., Ltd., L / D = 42, cylinder diameter 30 mm, cylinder temperature: 190 to 220 ° C., cross die head temperature: 220 ° C. )It was used. The pellet length was adjusted to 8 mm (the length of the organic long fiber was also 8 mm).
Next, the obtained organic long fiber reinforced polypropylene pellets were heated to a molten resin temperature of 210 ° C., and injection molded at a mold temperature of 40 ° C., an injection pressure of 60 MPa, and an injection speed of 100 mm / sec to obtain a mirror-finished flat plate. . Using this flat plate as a multipurpose test piece, the properties (material density, tensile elastic modulus, in-mold fluidity) of the molding material were evaluated according to the above criteria. Further, the surface density and appearance performance {(fiber floating, flow mark appearance (tiger stripe pattern)) of the molded product were evaluated by the above methods. The results are shown in Tables 1 and 2.

(Comparative Examples 1-4)
Polypropylene (A-1), talc (C-1), glass fiber (C-2), thermoplastic elastomer (D-1) and maleic anhydride-modified polyolefin (MH-PP) were used in the formulation shown in Table 2. It was prepared by melt-kneading at 210 ° C. with a twin-screw extruder (“TEX30” manufactured by Nippon Steel).
Next, the obtained organic long fiber reinforced polypropylene pellets were heated to a molten resin temperature of 210 ° C., and injection molded at a mold temperature of 40 ° C., an injection pressure of 60 MPa, and an injection speed of 100 mm / sec to obtain a mirror-finished flat plate. . Using this flat plate as a multipurpose test piece, the properties (material density, tensile elastic modulus, in-mold fluidity) of the molding material were evaluated according to the above criteria. Further, the surface density and appearance performance {(fiber floating, flow mark appearance (tiger stripe pattern)) of the molded product were evaluated by the above methods. The results are shown in Table 2.

"Evaluation"
From Table 1 and Table 2 showing the experimental results, the following can be understood. The fiber-reinforced lightweight parts of the present invention shown in Examples 1 to 13 are fiber-reinforced polyolefins containing 5 to 60 parts by weight of organic long fibers (B) with respect to 100 parts by weight of the propylene-based resin (A). Since the average surface density (product of the material density and the average thickness of the part design plane part) is less than 2 kg / m ^2, it is excellent in light weight and appearance performance, and has high-temperature rigidity. And non-scattering property at low temperature impact. Therefore, application to automobile interior parts is extremely useful. In Example 11, since a large amount of MH-PP was blended, the destructive scattering property was slightly lowered. Further, in Example 13, since the propylene resin having a slightly low MFR was used, the appearance performance was slightly deteriorated. However, if this is the case, there is no practical problem.

On the other hand, since the comparative example 1 used the fiber reinforced polyolefin resin material which does not contain an organic long fiber, thickness becomes large and a surface density becomes high, and Comparative Examples 2-3 contain an organic long fiber. Since fiber thickness is reduced by using a fiber reinforced polyolefin resin material that is not used, high rigidity and flow mark appearance performance are reduced. Since Comparative Example 4 contains glass fiber as an inorganic filler, The appearance performance due to is poor. Moreover, as for Comparative Examples 1-4, the non-scattering property at the time of a low temperature impact deteriorated all.
Moreover, although the comparative examples 5-6 used the fiber reinforced polyolefin-type resin material containing the organic long fiber, since the thickness was large and the surface density became high, the external appearance performance deteriorated, and the comparative example 7 is The appearance performance and moldability deteriorated because the organic long fiber content was increased. Therefore, it is difficult to apply these comparative examples to automobile interior parts.

  The lightweight automotive interior parts of the present invention have good moldability of molding material, light weight and appearance performance, high temperature rigidity and non-scattering property at low temperature impact, for example, instrument panel, door trim, console box It is useful as a pillar and the like.

Claims (7)

A fiber-reinforced propylene resin material containing 5 to 60 parts by weight of an organic long fiber (B) having a tensile strength of 5 cN / dtex or more is heated to a molten resin temperature with respect to 100 parts by weight of the propylene resin (A). A method of manufacturing a lightweight automotive interior part that is supplied and injection-molded into a mold whose inner surface has a predetermined shape ,
The injection molding is performed by setting the mold temperature to 30 to 50 ° C., the injection pressure to 40 to 100 MPa, and the injection speed to 50 to 200 mm / sec. A method for producing a lightweight automobile interior part , characterized in that the surface density (product of the material density and the average thickness of the part design plane part) is less than 2 kg / m ² . 2. The method for producing a lightweight automobile interior part according to claim 1, wherein in the fiber-reinforced propylene-based resin material, the organic long fibers (B) are polyester fibers and / or polyamide fibers. The fiber-reinforced propylene resin material further, with respect to the propylene resin (A) 100 parts by weight of an inorganic filler (C) 30 parts by weight or less and / or a thermoplastic elastomer (D) to contain less than 30 parts by weight The method for manufacturing a lightweight automobile interior part according to claim 1. 4. The fiber-reinforced propylene-based resin material according to claim 1, wherein in a product impact test at a low temperature, the weight of the scattered pieces after the test is less than 10% by weight of the product weight before the test . A method for producing a lightweight automotive interior part as described in 1 . The fiber-reinforced propylene-based resin material has a tensile modulus of elasticity at 80 ° C in accordance with JIS-K7161 of 1000 Mpa or more, and a broken piece is not scattered in a component impact test at a low temperature. Item 5. A method for producing a lightweight automobile interior part according to any one of Items 1 to 4 . Propylene resin (A) has a melt flow rate (conforming to JIS K7210, temperature 230 ° C., the value measured at a load 21.18 N) is according to claim 1-5, characterized in that it is 60 g / 10 min or more The manufacturing method of the lightweight automotive interior component in any one. Organic filaments (B) is a crystalline melting point (which is not observed in the melting point of softening point) of 200 ° C. or higher, or of claim 1-6, characterized in that non-thermoplastic according to any one of the lightweight automobile interior parts Manufacturing method .

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