JP2006083227A - Exterior molded article made of long fiber reinforced polyamide resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exterior molded article made of a long fiber reinforced polyamide resin superior in flexural modulus, mechanical strengths such as bending strength, chemical resistance and heat resistance, and having reduced mass, high latitude in a product design, a reduced maximum coefficient of linear expansion of the molded article due to fiber orientation when filled, reduced anisotropic characteristics of the coefficient of the linear expansion and a reduced rate of a maximum moisture absorption dimensional change. <P>SOLUTION: This exterior molded article made of a long fiber reinforced polyamide resin has a content of the reinforced fiber of 30-90 wt.% dispersed in the molded article, a weight average fiber length of 1.5-10 mm, a maximum projection area of the molded article of ≥20,000 mm<SP>2</SP>, a passage length of ≤150 mm in a narrow passage of a cross section of ≤100 mm<SP>2</SP>when molded, and following characteristics: (1) the maximum coefficient of linear expansion of ≤5×10<SP>-5</SP>K<SP>-1</SP>in a part of the molded article with ≥2 mm thickness, and the ratio of the maximum coefficient of linear expansion to the minimum coefficient of linear expansion of ≤1.8, and (2) the rate of a maximum moisture absorption dimensional change of ≤0.3% in the part of the molded article with ≥2 mm thickness. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an injection molded article of long fiber reinforced polyamide resin excellent in mechanical properties such as impact resistance and fluidity, and further, anisotropy of the molded article caused by fiber orientation during injection molding, In particular, the present invention relates to a long fiber reinforced polyamide resin exterior molded article, particularly an automobile exterior molded article, in which the maximum linear expansion coefficient, the anisotropy of the linear expansion coefficient, and the maximum moisture absorption dimensional change rate are reduced.

Polyamide resin is a resin that is used in many fields including the automotive and electrical / electronic fields by utilizing its excellent properties such as heat resistance, toughness, oil resistance, gasoline resistance, friction resistance, and moldability. It is. In particular, in the automobile field, there have been many uses, such as parts around the engine, utilizing the heat resistance and oil resistance. Conventionally, a structure in which a metal exterior panel is attached to a metallic structural component has been used for an automotive exterior component. However, in recent years, there has been a tendency to reduce the weight of various automobile parts for the purpose of improving the fuel efficiency and running performance of automobiles, and resin has come to be used in exterior panels and structures that support them. .
For example, Patent Document 1 discloses an automotive panel made of FRP in which a woven fabric base made of continuous fibers is used as a reinforcing fiber for the purpose of further reducing the weight of the automotive panel. We were not satisfied with point.
Patent Document 2 proposes a tailgate whose outer panel is made of polyphenylene ether / polyamide alloy and whose inner panel is made of long fiber reinforced polyamide / polyolefin alloy from the viewpoint of weight reduction and modularization. Due to the change in the moisture absorption dimension due to erection, there are problems in building and undulating appearance. Polycarbonate / polybutylene terephthalate alloy and the like have been proposed for the purpose of solving the problem of moisture absorption dimensional change, but the inner panel is a long fiber reinforced polypropylene, so an adhesive structure is required, and it depends on the fiber orientation of the inner panel. Although the anisotropy of linear expansion affects the outer panel, there is no description regarding the magnitude or anisotropy of linear expansion.

In Patent Document 3, as an exterior part for a vehicle, a carbon fiber having an average value of a linear expansion coefficient in the flow direction at the time of injection molding and a linear expansion coefficient in a direction perpendicular to the flow direction is 6 × 10 ⁻⁵ K ⁻¹ . Although reinforced polyamide is disclosed, there is no description regarding its anisotropy. If the anisotropy is large, the degree of deformation due to temperature change differs depending on the direction, which is not preferable because it may affect the appearance quality or cause the member to break or crack due to the occurrence of a stress concentration portion. Further, if the dimensional change due to moisture absorption or the anisotropy of the moisture absorption dimensional change is large, it is not preferable because a problem in building and a wavy appearance defect become problems.
Patent Document 4 discloses a thermoplastic resin obtained by injection molding a fiber reinforced thermoplastic resin material containing 3 to 70% by weight of a fibrous reinforcing material, such that (volume) / (surface area) <2 mm. In the molded product, the linear expansion coefficient at 23 ° C. to 100 ° C. in the flow direction (MD) of the molten resin containing the fibrous reinforcement and the direction perpendicular to the flow (TD) is 0.6 <(linear expansion in the TD direction). Coefficient) / (linear expansion coefficient in the MD direction) <2.5. However, it is necessary for the exterior structure of automobiles to have a small anisotropy. However, if the absolute value remains large, the buildability, the influence on peripheral parts, and coating defects and cracks due to linear expansion are also required. There is a risk of deteriorating the appearance quality. Furthermore, if a narrow channel with a small cross-sectional area exists in the molded body, the orientation of the reinforcing fibers becomes tight and the anisotropy increases, and depending on the channel length of the narrow channel, the entire molded body may be adversely affected. There is no description regarding the shape of the molded body. Moreover, there is no description regarding the hygroscopic dimensional change of the polyamide resin.

JP 2002-127944 A JP 2003-118379 A JP 2002-226703 A Japanese Patent Laid-Open No. 9-296053

  The problems to be solved by the present invention are excellent in mechanical strength such as bending elastic modulus and bending strength, chemical resistance and heat resistance, light weight, high degree of freedom in product design, and fiber orientation at the time of filling. An object of the present invention is to provide a long fiber reinforced automotive exterior molded body in which the maximum linear expansion coefficient, the anisotropy of the linear expansion coefficient, and the maximum moisture absorption dimensional change rate are reduced.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have identified the resin flow path in the mold cavity during molding, and the maximum is due to the fiber orientation of the long fiber reinforced automotive exterior molded body. The inventors have found that the coefficient of linear expansion, the anisotropy of the coefficient of linear expansion, and the maximum rate of change in moisture absorption dimension are reduced, and the present invention has been completed.

That is, the gist of the present invention is as follows: (1) The content of the reinforcing fiber dispersed in the molded body is 30% by weight to 90% by weight, and the weight average fiber length is 1.5 mm to 10 mm. The long-fiber-reinforced polyamide resin is characterized in that the maximum projected area is 20000 mm ² or more, the flow path length of a narrow channel having a cross-sectional area of 100 mm ² or less is 150 mm or less at the time of molding, and has the following properties: Made-to-mold molded body 1) The maximum linear expansion coefficient of a molded body portion having a thickness of 2 mm or more is 5 × 10 ⁻⁵ K ⁻¹ or less, and the ratio of the maximum linear expansion coefficient / minimum linear expansion coefficient is 1.8. 2) The maximum moisture absorption dimensional change rate of the molded part having a thickness of 2 mm or more is 0.3% or less.
(2) A long fiber reinforced polyamide resin exterior molded body, wherein the polyamide resin is polyamide 6 having a relative viscosity of 1.5 to 2.5 measured at 23 ° C. and 98% sulfuric acid at a concentration of 1%, (3) A long fiber reinforced polyamide resin exterior molded body in which the polyamide resin is an aromatic polyamide having a relative viscosity of 1.5 to 2.5 measured at 23 ° C. in 96% sulfuric acid at a concentration of 1%; (4) the polyamide A long fiber reinforced polyamide resin exterior molded body in which the resin is an aromatic polyamide resin whose main component is a polyamide obtained by a polycondensation reaction of an aromatic diamine and an aliphatic dicarboxylic acid, and (5) a long fiber as a molding material Using a mixture of the reinforced polyamide resin (A) and the recycled resin (B), the composition ratio is (A): 30% by weight to 100% by weight based on the weight of the mixture,
(B): 0% to 70% by weight
(6) The reinforcing fiber is a glass fiber having a specific diameter, or (7) the long fiber reinforced molded body is injection-molded. A long fiber reinforced polyamide resin exterior molded body is provided, and (8) an automotive exterior panel in which the long fiber reinforced molded body is an automotive exterior panel or a structure thereof is provided.

  In addition, another gist of the present invention is (9) having at least one non-reinforced resin layer laminated on the surface of the long fiber reinforced exterior molded body, and having a multilayer structure having a cross section of two or more layers. (10) The non-reinforcing resin layer is the same type of resin as the long fiber reinforced polyamide resin, or an alloy containing the resin as a main component, or (11) decoration of characters, emblems, marks, and the like during lamination An object is to provide a long-fiber reinforced automotive exterior molded body having an integrated design portion encapsulated between the long-fiber reinforced exterior molded body and the non-reinforced resin layer.

In the outer fiber reinforced polyamide resin exterior molded article of the present invention, the content of reinforcing fibers is 30% to 90% by weight, and the reinforcing fibers are dispersed with a weight average fiber length of 1.5 mm to 10 mm. A long fiber reinforced resin is used, and the length of the narrow channel with a cross-sectional area of 100 mm ² or less in the mold cavity at the time of molding is 150 mm or less. Excellent dimensional stability due to reduction of anisotropy and maximum moisture absorption dimensional change rate, excellent mechanical strength such as flexural modulus, flexural strength, chemical resistance, heat resistance, weight reduction, freedom of product design A large molded article suitable for a high-grade automobile exterior molded article can be manufactured.

Hereinafter, the present invention will be described in detail.
The long fiber reinforced polyamide resin exterior molded body of the present invention (hereinafter abbreviated as “the molded body of the present invention”) is significantly affected by the maximum linear expansion coefficient, the anisotropy of the linear expansion coefficient, and the maximum rate of change in the hygroscopic dimension. The maximum projected area of the molded body is larger than 20000 mm ² . In the case of molding using a fiber reinforced resin, it is generally said that the thick surface layer has the fibers oriented in the resin flow direction and the center layer oriented in the direction perpendicular to the flow direction. When the reinforcing fiber is a short fiber, the freedom of movement (rotation) of the fiber during molding increases, so the surface layer is oriented in the flow direction under shearing force from the wall surface, but the center layer is oriented in the random direction. There are many cases. When the reinforcing fiber is a long fiber, the freedom of movement (rotation) of the reinforcing fiber is reduced due to the effect of the fiber length, and it can be said that the surface layer tends to have a clear orientation in the flow direction and the center layer in the perpendicular direction. .
Another feature of the molded body of the present invention is the relationship between the cross-sectional area of the narrow channel and the channel length at the time of molding, and the channel length of the narrow channel having a cross-sectional area of 100 mm ² or less is 150 mm or less. More preferably, the length of the narrow channel having a cross-sectional area of 80 mm ² or less is desirably 100 mm or less. If the channel length of a narrow channel having a cross-sectional area of 100 mm ² or less during molding exceeds 150 mm, the orientation direction of the reinforcing fibers is often oriented in the filling direction of the molten resin, and the line in the filling direction Although the effect of reducing the expansion coefficient and the effect of reducing the shrinkage are increased, the effect in the perpendicular direction is reduced, and thus the anisotropy is increased. If the anisotropy is large, there is a risk that it may lead to deterioration in appearance quality due to poor installation due to linear expansion or coating cracks, as well as the ease of installation required for exterior parts, effects on peripheral parts and gaps. is there. Similarly, the rate of dimensional change due to moisture absorption is increased, resulting in problems such as building defects and wavy appearance defects.

Furthermore, the other feature of the molded body of the present invention is that the reinforcing fiber content in the molded body is 30% by weight to 90% by weight, and the length of the reinforcing fiber is 1.5 mm to It exists in being disperse | distributed with the weight average fiber length of 10 mm, and also in a molded object having the following various properties.
1) The maximum linear expansion coefficient of the molded part having a thickness of 2 mm or more is 5 × 10 ⁻⁵ K ⁻¹ or less, and the ratio of the maximum linear expansion coefficient / minimum linear expansion coefficient is 1.8 or less. .
This property is obtained by measuring a linear expansion coefficient in a temperature range of 23 ° C. to 80 ° C. at an arbitrary position (multiple locations) of a molded body portion having a wall thickness of 2 mm or more, and measuring the maximum value (maximum line). It can be easily determined by checking the expansion coefficient) and the minimum value (minimum linear expansion coefficient) and calculating the ratio between them (maximum linear expansion coefficient / minimum linear expansion coefficient ratio).
2) The maximum moisture absorption dimensional change rate of a molded body portion having a thickness of 2 mm or more is 0.3% or less.
This property is measured by measuring the dimensional change of the surface of the molded body caused by water absorption during saturated water absorption at a temperature of 23 ° C. and a relative humidity of 50% at any position (multiple locations) of the molded body part with a thickness of 2 mm or more. And calculate the moisture absorption dimensional change rate of the following formula from those measured values,
Hygroscopic dimensional change rate = [(dimension after water absorption−dimension before water absorption) / dimension before water absorption] × 100
It can be easily determined by checking the maximum value (maximum moisture absorption dimensional change rate) of those calculated values.
Thus, when the content of the reinforcing fiber is less than 30% by weight, or when the weight average fiber length is less than 1.5 mm, mechanical strength and dimensional stability including bending elastic modulus and bending strength are obtained. Since it falls, it is not preferable. Moreover, when the content rate of the said reinforced fiber exceeds 90 weight% or a weight average fiber length exceeds 10 mm, since a moldability falls, it is unpreferable.
When the maximum linear expansion coefficient is greater than 5 × 10 ⁻⁵ K ⁻¹ and when the ratio of the maximum linear expansion coefficient / minimum linear expansion coefficient is greater than 1.8, the deformation amount of the entire molded body with respect to the temperature change is Due to the large size required for building parts, effects on peripheral parts and effects on gaps, cracking due to deformation, distortion of appearance, coating cracks, and linear expansion during coating of molded products This is not preferable because the appearance quality may be deteriorated due to poor coating or cracking. Furthermore, when the maximum value of the maximum moisture absorption dimensional change rate is larger than 0.3%, the dimensional change caused by water absorption causes problems in installation, influence on peripheral parts, influence on gap amount, and undulating appearance defect. Therefore, it is not preferable.

  The reinforcing fiber constituting the molded body of the present invention has a weight average fiber length of 1.5 mm to 10 mm, and preferably a long fiber of 2 mm to 7 mm for a front structure having better mechanical strength and dimensional stability. As long as it can be dispersed in the molded body, there is no particular limitation. Usually, glass fiber, carbon fiber, metal fiber, synthetic fiber and the like used for resin reinforcement can be used, but glass fiber and carbon fiber are practical. The diameter of the carbon fiber is preferably 5 μm to 15 μm. In addition, the reinforcing fiber has a sizing agent or a surface treatment agent (for example, an epoxy compound, an acrylic compound, an isocyanate compound, a silane compound, a titanate compound, etc.) in order to improve the interfacial adhesion with the polyamide resin. It is preferable to use a surface-treated compound.

When the reinforcing fibers constituting the molded article of the present invention are glass fibers, the diameter is preferably 10 μm to 20 μm from the viewpoint of further improving the breakage of the glass fibers and the balance of physical properties.
The glass fiber actually used has a glass composition such as A glass, C glass, or E glass, and E glass (non-alkali glass) is particularly preferable because it does not adversely affect the thermal stability of the polyamide resin. The manufacturing method of glass fiber is based on the following method, for example. First, melted glass is formed into a glass ball of a predetermined size called marble, heated and softened in a yarn-taking furnace called pushing, and allowed to flow down from a number of nozzles of the furnace table. While stretching, the sizing agent is attached by immersing with a sizing agent coating apparatus provided in the middle of the squeezing agent to squeeze it, and it is dried and wound on a rotating drum. At this time, the average diameter of the glass fiber is set to a predetermined dimension by adjusting the nozzle diameter, the take-up speed, the take-up atmosphere temperature, and the like.

When the reinforcing fibers constituting the molded article of the present invention are carbon fibers, the diameter is preferably 5 μm to 15 μm from the viewpoint of further improving the breakage of the carbon fibers and the balance of physical properties.
The carbon fiber actually used is generally produced by firing using acrylic fiber, petroleum or carbon-based special pitch, cellulose fiber, lignin, etc. as a raw material, and various types of flame resistant, carbonaceous, graphite, etc. There is something, but it is not limited to a specific thing.

  As the polyamide resin constituting the molded article of the present invention, various polymers and copolymers obtained by polycondensation of ω-amino acids or lactams thereof and / or polycondensation of diamine and dicarboxylic acid are used. be able to. Specifically, α-pyrrolidone, α-piperidone, ε-caprolactam, aminocaproic acid, enantolactam, 7-aminoheptanoic acid, 8-aminooctanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, 12-aminododecane Polymers such as acids, diamines such as hexamethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine, metaxylylenediamine, terephthalic acid, isophthalic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, There are polymers obtained by polycondensation with dicarboxylic acids such as undecanedioic acid and dodecanedioic acid, or copolymers thereof, such as polyamide 4, polyamide 6, polyamide 7, polyamide 8, polyamide 11, polyamide 12, Polyamide 6-6, polyamide 6 9, polyamide 6-10, polyamide 6-11, polyamide 6-12, polyamide 6T, copolymer polyamide 6 / 6-6, copolymer polyamide 6/12, copolymer polyamide 6 / 6T, copolymer polyamide 6I / 6T, etc. Is mentioned. Preferred examples include polyamide 6, polyamide 6-6, and copolymerized polyamide 6 / 6-6. Particularly preferred is polyamide 6. An aromatic polyamide resin mainly composed of a polyamide obtained from a polycondensation reaction between an aromatic diamine and an aliphatic dicarboxylic acid is also preferable. Examples of the aromatic diamine include paraxylylenediamine and metaxylylenediamine, and it is preferable to use a mixed diamine of paraxylylenediamine and metaxylylenediamine. The reason why the long fiber reinforced polyamide resin is selected as the exterior molded body material of the present invention is that the long fiber reinforced polyamide resin has mechanical strength, oil resistance, chemical resistance, compared to other long fiber reinforced thermoplastic resins such as polyester. This is because the material is excellent in heat resistance, durability, and moldability, and is particularly excellent in impact strength, fatigue characteristics, and creep characteristics at high temperatures.

  The polyamide resin constituting the molded article of the present invention preferably has a degree of polymerization within a certain range, that is, a relative viscosity within a specific range. The preferred relative viscosity is 1.5 to 2.5 as measured by polyamide 6 at 23 ° C. and 98% sulfuric acid at a concentration of 1%, and aromatic polyamide at 23 ° C. and 96% sulfuric acid at a concentration of 1%. More preferably, it is 1.7-2.4. When the relative viscosity is less than 1.5, the mechanical strength is low, and when it exceeds 2.5, the fluidity is lowered, the breakage of the long fiber is increased at the time of molding, and the mechanical strength is lowered.

The molded product of the present invention is molded using a long fiber reinforced polyamide resin (A) as a molding material, or a mixture in which the recycled resin (B) described later is blended with (A) as necessary. The methods include molding methods generally used for polyamide resins, that is, various molding methods such as injection molding, injection compression molding, hollow molding, extrusion molding, sheet molding, thermoforming, rotational molding, laminate molding, press molding, and the like. However, it is particularly preferable to mold by an injection molding method from the viewpoint of the appearance of the molded product, the degree of freedom in design, and the reduction of the manufacturing process. When molding the long fiber reinforced polyamide resin (A), there is a risk that the reinforcing fiber is usually crushed at the time of melting and kneading in the cylinder of the molding machine and filling the mold, and the length of the fiber is shortened. In order to maintain the weight average fiber length of the reinforcing fibers dispersed in the molded product of the present invention within the range of 1.5 mm to 10 mm, the length of the pellet, the shape of the cylinder inner wall of the molding machine, the screw shape, molding conditions (for example, It is effective to adjust the mold shape and the like including the point of the narrow flow path, the resin temperature at the time of molding, the injection speed). In addition, a vehicle body front structure having high rigidity and high strength can be obtained by providing a boss, a rib structure, or the like. Furthermore, pressurized gas can be injected into the ribs and bosses. It is also possible to provide a movable part in the mold in order to further improve the rigidity and to make it hollow by injecting pressurized gas into the capacity expansion part due to the movement of the movable part, and to have a sectional shape with high sectional rigidity. In addition, it is possible to fill and reinforce the formed hollow portion with a foam, a low melting point metal or the like, and to further improve the rigidity strength.
Moreover, other components can be added to the long fiber reinforced polyamide resin (A) or the like, which is a molding material of the molded article of the present invention, as necessary. Other components include, for example, stabilizers, flame retardants, weather resistance improvers, foaming agents, lubricants, fluidity improvers, impact resistance improvers, antistatic agents, dyes, pigments, dispersants, inorganic reinforcing agents, Examples include mold release agents, antioxidants, weather resistance improvers, alkali soaps, metal soaps, hydrotalcites, plasticizers, nucleating agents, and anti-dripping agents. Examples of the impact resistance improving material include polyolefin resins such as polyethylene and polypropylene, α-olefin rubber, styrene rubber, acrylic rubber, silicon rubber, MBS, and core-shell polymer. Specific examples of the inorganic reinforcing agent include glass fibers other than long fibers, carbon fibers, aramid fibers, mica, talc, wollastonite, potassium titanate, calcium carbonate, silica and the like.

  The method for producing the long fiber reinforced polyamide resin (A), which is a molding material of the molded article of the present invention, is preferably a drawing method. The drawing method is basically a method of impregnating a resin while drawing a continuous reinforcing fiber bundle, a method of impregnating a resin through an impregnation bath containing a resin emulsion, suspension or solution, and a resin powder. A method in which the fiber is passed through the fiber or the fiber is passed through the tank and the resin powder is adhered to the fiber, and then the resin is melted and impregnated. From the extruder to the crosshead while passing the fiber through the crosshead. Methods for supplying and impregnating molten resin are known, and any of them can be used. Particularly preferred as the molding material is a length of 3.0 to 50 mm, preferably 4 mm, after the molten polyamide is supplied to the crosshead from an extruder or the like while passing the fibers through the crosshead, impregnated and cooled. It is cut into a pellet of 0 to 30 mm. The reinforcing fibers in the pellets thus obtained are almost parallel to the pellets, so that the length of the reinforcing fibers is equal to the length of the pellets. If the length of the pellet is less than 3.0 mm, the length of the reinforcing fiber is also shortened and the reinforcing effect is small. Conversely, if the length of the pellet exceeds 50 mm, the bulk density increases, and a bridge is generated in the hopper during the molding process. Or bite into the screw, and stable molding may not be possible.

When using the mixture which mix | blended the recycled resin (B) with the long fiber reinforced polyamide resin (A) as a molding material of this invention molded object, the composition ratio is based on the weight of this mixture. (A): 30 weight%- 100% by weight,
(B): 0% to 70% by weight
It is preferable to be within the range. If the long fiber reinforced polyamide resin (A) is less than 30% by weight, the mechanical strength, dimensional stability, appearance and the like are greatly deteriorated. Moreover, it is preferable that the shape and size of the long fiber reinforced polyamide resin (A) and the recycled resin (B) are as close as possible to prevent classification in the molding process.

  As the molding material of the molded article of the present invention, the recycled resin (B) blended in the long fiber reinforced polyamide resin (A) is not particularly limited, and may be a recycled product of polyamide resin in terms of compatibility. When recycled from at least one thermoplastic resin selected from the group consisting of polyethylene, polystyrene, and acrylonitrile / styrene / butadiene copolymers, it has excellent fluidity and is suitable for use as a molding material for large molded articles. it can. Moreover, you may mix | blend a compatibility improvement agent as needed.

  This recycled resin (B) includes purge resin, sprue, runner during molding, defective products generated during the molding, secondary processing, assembly process, etc., and molding recovered after use for the intended use. Recycled products from various stages such as products. Needless to say, the shape of the molded product is not limited, and specifically, a recycled product obtained by pulverizing a molded product such as an outer plate of an automobile, an electric / electronic / OA device, a mechanical part, or the like can be used. However, molded articles with many deposits such as solvents and fats and oils are not preferable because they cause mechanical strength, thermal stability and appearance deterioration.

  The blending method of the recycled resin (B) with the long fiber reinforced polyamide resin (A) is not particularly limited, and various known mixing devices such as a Henschel mixer, a ribbon blender, a V-type blender, and an extruder. , Banbury mixer, Laboplast mill (Brabender), kneader, etc. can be used.

In order to make the molded body of the present invention into an automotive exterior molded body, it is required to be a bonnet, roof, hood, front panel, canopy, trunk lid, door panel, pillar, and similar automotive exterior panels or structures thereof. This is preferable in terms of the dimensional accuracy.
In the present invention, a long fiber reinforced polyamide resin exterior molded body has at least one non-reinforced resin layer laminated on the outer surface thereof, and has a long fiber reinforcement in a cross section perpendicular to the laminated surface. The layer thickness ratio of the layer / non-reinforced resin layer is preferably 1.0 or more, and more preferably 1.2 or more. When the layer thickness ratio of the long fiber reinforced layer / non-reinforced resin layer is less than 1.0, a difference in linear expansion between the long fiber reinforced layer and the non-reinforced resin layer is caused by molding of the long fiber reinforced molded body and / or due to temperature environment change. This is not preferable because there is a risk of warping. The non-reinforced resin used for the lamination is not particularly limited, but is preferably the same type of resin as the long fiber reinforced polyamide resin or an alloy containing the resin as a main component in terms of adhesion. Moreover, in the case of the said lamination | stacking, the decoration part containing a character, an emblem, and / or a mark can also be enclosed between this long fiber reinforced molded object and this non-reinforced resin layer. Such a molded body is useful as an automotive exterior molded body having excellent appearance characteristics, design properties, and design durability.

  In the present invention, as a method of forming at least one non-reinforced resin layer laminated on the outer surface of a long fiber reinforced polyamide resin exterior molded body, a processing method generally used for thermoplastic resins, Simultaneously with injection molding, at least one non-reinforced resin layer, for example, a method of laminating non-reinforced resin film or sheet, transfer molding, two-color molding, double molding, hot plate welding, vibration welding, laser welding, etc. A method of laminating the film or sheet at the same time as injection molding is particularly preferable from the viewpoint of the appearance of the molded product, the degree of freedom in design, and the reduction of the manufacturing process.

  In the present invention, when the film or sheet is laminated simultaneously with the injection molding, the film or sheet is added to the film or sheet for the purpose of accelerating heat fusion with the resin composition at the time of melt injection filling and making the lamination integration more reliable. A primer coat can also be applied. As the resin used for the primer coating, a resin having a melt viscosity higher than that of the polyamide resin constituting the molded body and adhering well to the film or sheet is selected. For example, there are resins having the same kind and higher molecular weight as the polyamide resin or those mainly composed of this resin, and resins curable by heat or ultraviolet rays.

  The molded product of the present invention may be provided with at least one functional layer selected from the group consisting of hard coating, anti-fogging, antistatic, antireflection, and heat ray blocking on one side, or by surface addition by painting or transfer, as desired. Can be decorated. Various conventionally known methods are used to form the functional layer. For the formation of the hard coat layer, a primer layer is provided if desired, and a hard coat agent such as epoxy, acrylic, amino resin, polysiloxane, or colloidal silica is applied, and means such as heat or ultraviolet rays A curing method can be used. For the formation of the antifogging layer, a method of applying an antifogging coating usually containing a water-soluble or hydrophilic resin and a surfactant as essential components and curing can be used. In addition, the antistatic layer, the antireflection layer, the heat ray blocking layer, etc. may be applied with a coating material that provides these functions and cured, or a thin film layer having these functions may be formed by a method such as vacuum deposition. I can do it. Further, these functional layers may be combined to have two or more functions at the same time. Furthermore, it is also possible to form a designability-imparting layer by a method such as applying a cosmetic coating treatment to the functional layer in advance or imparting design properties to the functional layer.

  Hereinafter, the present invention will be described in detail by way of preferred embodiments with reference to the drawings, but the present invention is not limited to these ranges. In the following examples,% is% by weight unless otherwise specified.

[Evaluation]
Evaluation 1. Fiber content, cut out randomly specimens from any position of the weight average fiber length shaped long fiber-reinforced polyamide resin cladding molded body was burned only the thermoplastic resin component in an electric furnace at 500 ° C., The weight and length of the remaining fiber were measured, the ratio to the weight of the test piece before combustion was taken as the content, and the weight average value of the fiber length was taken as the weight average fiber length.
Evaluation 2. Relative viscosity (ηrel)
Randomly cut out from any position of the molded long fiber reinforced polyamide resin exterior molded body and expressed as a relative viscosity measured at 23 ° C., 98% sulfuric acid at a concentration of 1%. In the case of an aromatic polyamide, it was expressed as a relative viscosity measured at 23 ° C. and 96% sulfuric acid at a concentration of 1%.
Evaluation 3. Mechanical properties Molded long fiber reinforced polyamide resin exterior molded body Randomly cut out 80 mm x 10 mm strip-shaped test pieces from any position with a thickness of 2 mm or more, bending elastic modulus, bending strength according to ISO 178, Notched Charpy impact strength was measured according to ISO 179. The measurement was performed with the number of test pieces n = 10.
Evaluation 4. A strip-shaped test piece of 30 mm × 10 mm is randomly cut out from an arbitrary position of a wall thickness of 2 mm or more of a long fiber reinforced polyamide resin exterior molded body formed with a linear expansion coefficient, and linear expansion in a temperature range of 23 ° C. to 80 ° C. The coefficient was measured. The measurement was carried out with the number of test pieces n = 10, and was carried out in two directions orthogonal to each test piece, and the ratio was calculated by dividing the maximum linear expansion coefficient by the minimum linear expansion coefficient. It is estimated that the smaller this ratio is, the more the anisotropy is reduced.
Evaluation 5. The long-fiber reinforced polyamide resin exterior molded body molded with the maximum moisture absorption dimensional change rate was subjected to water absorption treatment until a saturated water absorption state at a temperature of 23 ° C. and a relative humidity of 50%, and as shown in FIGS. Before and after water absorption using markings indicating the positions of the four corners of at least 5 squares (the length of one side is about 25 to 50 mm) drawn at an arbitrary position on the surface of the molded part having a thickness of 2 mm or more The vertical and horizontal dimensions were measured, the hygroscopic dimensional change rate (%) of the following formula was calculated, and the maximum value was displayed.
Hygroscopic dimensional change rate = [(dimension after water absorption−dimension before water absorption) / dimension before water absorption] × 100
In Example 5 and Comparative Example 6, the marking shown in FIG. 1 was performed on the surface of the obtained molded body and used for calculating the maximum moisture absorption dimensional change rate.

[Example 1]
Preparation of long glass fiber reinforced polyamide resin pellets Opening a continuous glass fiber bundle (roving) and passing it through the impregnation die, impregnating the molten resin supplied to the impregnation die, shaping, cooling, Using a pultrusion method for cutting, glass long fiber reinforced polyamide resin pellets having a fiber content of 30% and a length of 10 mm were produced. As the resin, polyamide 6 (manufactured by Mitsubishi Engineering Plastics, product name Novamid 1007J, relative viscosity 2.2) was melted and used. The glass fibers in the obtained pellets had a diameter of 16 μm, had the same length as the pellets, and were arranged substantially parallel to the length direction of the pellets.

Injection Molding of Outer Molded Article A flat outer molded article having a thickness of 3 mm, 150 mm × 150 mm, and a maximum projected area of 22500 mm ² shown in FIG. 1 attached thereto was molded using an IS-150 injection molding machine manufactured by Toshiba Machine. That is, the long fiber reinforced polyamide resin pellets prepared as described above were supplied to a heating cylinder of an injection molding machine heated to 270 ° C., and plasticized, melted, and weighed. The plasticization and measurement were performed while applying a back pressure of 5 MPa with the gauge pressure of the injection molding machine. After the weighing, the mold cavity was filled by injection through the illustrated resin gate. The injection time was set to 2 seconds, the holding pressure of 100 MPa was applied for 20 seconds with the gauge pressure of the injection molding machine, the mold was opened after the cooling time of 25 seconds had elapsed, and the long fiber reinforced polyamide resin exterior molded product was taken out to finish molding. The mold temperature at this time was 70 ° C.
The long fiber reinforced exterior molded body thus obtained was a highly rigid structure. Moreover, about the test piece cut out from this molded object, the result of having evaluated fiber content rate, a weight average fiber length, a mechanical property, a linear expansion coefficient, a hygroscopic dimensional change rate, and a relative viscosity is shown in postscript Table-1. The mechanical properties in the evaluation results were all very high, and further, the linear expansion coefficient, the linear expansion anisotropy, and the moisture absorption dimensional change were all small, satisfying the function as an automobile exterior molded article.

[Example 2]
In Example 1, a long fiber reinforced exterior molded body was molded in the same manner as in Example 1 except that the fiber content 30% was changed to 50% when the long fiber reinforced polyamide resin pellets were prepared.
The long fiber reinforced exterior molded body thus obtained was a highly rigid structure. Moreover, about the test piece cut out from this molded object, the result of having evaluated fiber content rate, a weight average fiber length, a mechanical property, a linear expansion coefficient, a hygroscopic dimensional change rate, and a relative viscosity is shown in postscript Table-1. The mechanical properties in the evaluation results were all very high, and the linear expansion coefficient, the linear expansion anisotropy, and the hygroscopic dimensional change rate were all small, satisfying the function as an automotive exterior molded article.

[Example 3]
In Example 2, when preparing the long fiber reinforced polyamide resin pellets, instead of the polyamide 6, aromatic polyamide (manufactured by Mitsubishi Engineering Plastics, product name Reny 6002, relative viscosity 2.1, MXD6-PA is abbreviated as MXD6-PA). ), And during the injection molding, a long fiber reinforced exterior molded body was obtained in the same manner as in Example 2 except that the heating cylinder temperature of the injection molding machine was 270 ° C. and the mold temperature 70 ° C. was 135 ° C. Was molded.
The long fiber reinforced exterior molded body thus obtained was a highly rigid structure. Moreover, the result of having evaluated the fiber content rate, the weight average fiber length, the mechanical property, the linear expansion coefficient, and the hygroscopic dimensional change rate about the test piece cut out from this molded object is shown in the postscript Table-1. The mechanical properties in the evaluation results were all very high, and further, the linear expansion coefficient, the linear expansion anisotropy, and the hygroscopic dimensional change rate were all small, satisfying the function as an automotive exterior molded article.

[Example 4]
In Example 2, at the time of injection molding of the exterior molded body, instead of the flat plate-shaped molded body shown in FIG. 1 attached, it has a thickness of 3 mm, 150 mm × 200 mm, and has a partially cutaway portion. the maximum projected area 27300Mm ^2, the cross-sectional area 90 mm ^2, except that the outer molded body having a narrow channel of the channel length 45mm was molded long fiber-reinforced outer molded body in the same manner as in example 2.
The long fiber reinforced exterior molded body thus obtained was a highly rigid structure. Moreover, about the test piece cut out from this molded object, the result of having evaluated fiber content rate, a weight average fiber length, a mechanical property, a linear expansion coefficient, a hygroscopic dimensional change rate, and a relative viscosity is shown in postscript Table-1. The mechanical properties in the evaluation results were all very high, and further, the linear expansion coefficient, the linear expansion anisotropy, and the hygroscopic dimensional change rate were all small, satisfying the function as an automotive exterior molded article.

[Example 5]
In Example 2, at the time of injection molding of the outer molded body, the size of the mold cavity was changed to 4 mm and 150 mm × 150 mm, and both the cavity surfaces were made of polyamide 6 having a thickness of 0.5 mm previously formed. An exterior molded body (maximum projected area: 22500 mm ² ) in which a non-reinforced resin layer was laminated on both sides of a long fiber reinforced resin layer was molded in the same manner as in Example 2 except that a film was attached. The thickness ratio of the long fiber reinforced resin layer / non-reinforced resin layer in this laminated flat plate-shaped molded body was 3. A cross mark was printed by screen printing on one side of the polyamide 6 film for evaluation of misalignment or the like, and the film was molded so as to enclose the printed side.
The long fiber reinforced exterior molded body thus obtained was a molded body having excellent surface smoothness and high rigidity. Moreover, about the test piece cut out from this molded object, the result of having evaluated fiber content rate, a weight average fiber length, a mechanical property, a linear expansion coefficient, a hygroscopic dimensional change rate, and a relative viscosity is shown in postscript Table-1. The mechanical properties in the evaluation results were all very high, and further, the linear expansion coefficient, the linear expansion anisotropy, and the hygroscopic dimensional change rate were all small, satisfying the function as an automotive exterior molded article.

[Comparative Example 1]
In Example 1, a long fiber reinforced exterior molded body was molded in the same manner as in Example 1 except that the fiber content was changed to 30% instead of 30% when preparing the glass long fiber reinforced polyamide resin pellets.
The long fiber reinforced exterior molded article thus obtained was a molded article having a low rigidity. Further, Table 2 shows the results of evaluating the fiber content, the weight average fiber length, the mechanical properties, the linear expansion coefficient, and the relative viscosity of the test piece cut out from the molded body. Although the weight average fiber length of the molded body was 2.8mm and long result, undervalued both mechanical properties in the results, furthermore, the maximum linear expansion coefficient of 7.0 × 10 ^-5 K ^-1, anisotropic The properties (maximum linear expansion coefficient / minimum linear expansion coefficient ratio) were as large as 1.9 and the maximum hygroscopic dimensional change rate was 0.65%, all of which did not satisfy the function as an exterior molded article for automobiles.

[Comparative Example 2]
In Example 1, it replaced with the glass long fiber reinforced polyamide resin pellet preparation, and it was the same as Example 1 except having used polyamide 6 (Mitsubishi Engineering Plastics Co., Ltd., brand name Novamid 1013GH30) with a fiber content of 30%. A long fiber reinforced exterior molded article was molded.
The long fiber reinforced exterior molded product thus obtained was a molded product with a high rigidity. In addition, the test piece cut out from the molded product, the fiber content, the weight average fiber length, the mechanical properties, the linear expansion coefficient, and the relative viscosity are shown in Table 2 below. Since the length is as short as 0.41 mm, the impact strength in the evaluation result is low, the maximum linear expansion coefficient is 7.1 × 10 ⁻⁵ K ⁻¹ , the anisotropy is 2.2, and the maximum moisture absorption dimensional change rate is 0.00. All of them were as large as 32% and did not satisfy the function as exterior molded articles for automobiles.

[Comparative Example 3]
In Example 2, at the time of injection molding of the exterior molded body, instead of the flat plate-shaped molded body shown in FIG. 1 attached, it has a thickness of 3 mm, 150 mm × 200 mm, and has a partially cutaway portion. the maximum projected area 23600Mm ^2, the cross-sectional area 100 mm ^2, except that the outer molded body having a narrow channel of the channel length 160mm was molded long fiber-reinforced outer molded body in the same manner as in example 2.
The long fiber reinforced exterior molded product thus obtained was a molded product with a high rigidity. In addition, the test piece cut out from the molded body was evaluated in terms of fiber content, weight average fiber length, mechanical properties, linear expansion coefficient, hygroscopic dimensional change rate, and relative viscosity, as shown in Table 2 below. The maximum linear expansion coefficient in the evaluation results is 6.0 × 10 ⁻⁵ K ⁻¹ , the anisotropy is 2.3, and the maximum hygroscopic dimensional change rate is 0.36%, all of which are functions as an automotive exterior molded body. It was not satisfied.

[Comparative Example 4]
In Example 2, at the time of injection molding of the exterior molded body, instead of the flat plate-shaped molded body shown in FIG. 1 attached, it has a thickness of 3 mm, 150 mm × 200 mm, and has a partially cutaway portion. the maximum projected area 20400Mm ^2, the cross-sectional area 90 mm ^2, except that the outer molded body having a narrow channel of the channel length 160mm was molded long fiber-reinforced outer molded body in the same manner as in example 2.
The long fiber reinforced exterior molded product thus obtained was a molded product with a high rigidity. In addition, the test piece cut out from the molded body was evaluated in terms of fiber content, weight average fiber length, mechanical properties, linear expansion coefficient, hygroscopic dimensional change rate, and relative viscosity, as shown in Table 2 below. The maximum linear expansion coefficient in the evaluation results is 6.5 × 10 ⁻⁵ K ⁻¹ , the anisotropy is 3.0, and the maximum moisture absorption dimensional change rate is 0.41%, all of which are functions as an automotive exterior molded body. It was not satisfied.

[Comparative Example 5]
In Example 2, polyamide 6 (Mitsubishi Engineering Plastics Co., Ltd.) was used instead of polyamide 6 (manufactured by Mitsubishi Engineering Plastics, product name Novamid 1007J, relative viscosity 2.2) when preparing the long glass fiber reinforced polyamide resin pellets. A long fiber reinforced exterior molded article was molded in the same manner as in Example 2 except that manufactured product name Novamid 1030J and relative viscosity 4.5) were used.
The long fiber reinforced molded product thus obtained was a molded product with high rigidity. Further, the test piece cut out from the molded body, the fiber content, weight average fiber length, mechanical properties, linear expansion coefficient, hygroscopic dimensional change rate, the results of evaluating relative viscosity are shown in Table 2 below. Since the weight average fiber length of the body is as short as 0.91 mm, the impact strength in the evaluation results is low, the maximum linear expansion coefficient is 6.5 × 10 ⁻⁵ K ⁻¹ , the anisotropy is 2.0, and the maximum moisture absorption dimension The rate of change was as large as 0.32%, and did not satisfy the function as an automobile exterior molded body.

[Comparative Example 6]
In Example 5, in the case of injection molding of the outer molded body, except that a polyamide 6 film having a thickness of 1.1 mm was attached to both cavity surfaces of the mold instead of the polyamide 6 film having a thickness of 0.5 mm. In the same manner as in Example 5, an exterior molded body in which a non-reinforced resin layer was laminated on both sides of a long fiber reinforced resin layer was molded. The thickness ratio of the long fiber reinforced resin layer / non-reinforced resin layer in the laminated flat molded body was 0.82.
The long fiber reinforced exterior molded article thus obtained was a molded article excellent in surface smoothness. In addition, the test piece cut out from the molded body was evaluated in terms of fiber content, weight average fiber length, mechanical properties, linear expansion coefficient, hygroscopic dimensional change rate, and relative viscosity, as shown in Table 2 below. The mechanical properties such as rigidity and strength in the evaluation results are all low, the maximum linear expansion coefficient is 7.0 × 10 ⁻⁵ K ⁻¹ , the anisotropy is 2.1, and the maximum hygroscopic dimensional change rate is 0.00. All of them were as large as 37% and did not satisfy the function as an automobile exterior molded article.

[Comparative Example 7]
In Comparative Example 2, instead of polyamide 6 having a fiber content of 30% (trade name Novamid 1013GH30 manufactured by Mitsubishi Engineering Plastics), an aromatic polyamide having a fiber content of 50% (trade name MX nylon manufactured by Mitsubishi Gas Chemical Co., Ltd.) A long fiber reinforced exterior molded body was molded in the same manner as in Comparative Example 2 except that S6121, relative viscosity 3.65, and abbreviated as MX) were used.
The long fiber reinforced exterior molded product thus obtained was a molded product with a high rigidity. In addition, the test piece cut out from the molded product, the fiber content, the weight average fiber length, the mechanical properties, the linear expansion coefficient, and the relative viscosity are shown in Table 2 below. Since the length was as short as 0.55 mm, the impact strength in the evaluation result was remarkably low, and the function as an exterior molded article for automobiles was not satisfied.

The top view and side view of an exterior molded object obtained in Examples 1-3 and Comparative Examples 1, 2, and 5. The top view and sectional drawing of an exterior molded object obtained in Example 4. FIG. The top view and conceptual sectional drawing of the exterior molded object obtained by the comparative example 3. FIG. The top view and sectional drawing of the exterior molded object obtained by the comparative example 4. FIG.

Claims (12)

The content of the reinforcing fibers dispersed in the molded body is 30% by weight to 90% by weight, the weight average fiber length is 1.5 mm to 10 mm, and the maximum projected area of the molded body is 20000 mm ² or more, flow path length of the cross-sectional area 100 mm ² or less narrow channel at the time of molding is not less 150mm or less, and, long-fiber-reinforced polyamide resin cladding moldings, characterized in that it comprises the following properties.
1) The maximum linear expansion coefficient of a molded part having a thickness of 2 mm or more is 5 × 10 ⁻⁵ K ⁻¹ or less, and the ratio of the maximum linear expansion coefficient / minimum linear expansion coefficient is 1.8 or less. ) The maximum hygroscopic dimensional change rate of the molded part having a thickness of 2 mm or more is 0.3% or less.   2. The long-fiber-reinforced polyamide resin according to claim 1, wherein the polyamide resin is polyamide 6 having a relative viscosity of 1.5 to 2.5 measured at 23 ° C. and 98% sulfuric acid at a concentration of 1%. Exterior molded body.   2. The long fiber reinforced polyamide resin according to claim 1, wherein the polyamide resin is an aromatic polyamide having a relative viscosity of 1.5 to 2.5 measured at 23 [deg.] C. in 96% sulfuric acid at a concentration of 1%. An exterior molded article.   2. The long-fiber-reinforced polyamide resin according to claim 1, wherein the polyamide resin is an aromatic polyamide resin mainly comprising a polyamide obtained by a polycondensation reaction between an aromatic diamine and an aliphatic dicarboxylic acid. Exterior molded body. As the molding material, a mixture in which the recycled resin (B) is blended with the long fiber reinforced polyamide resin (A) is used, and the composition ratio is (A): 30% by weight to 100% by weight based on the weight of the mixture,
(B): 0% to 70% by weight
The long-fiber reinforced polyamide resin-made exterior molded body according to any one of claims 1 to 4, wherein the outer-molded body is within the range of 1).   The recycled resin (B) is a recycled product of at least one thermoplastic resin selected from the group consisting of polypropylene, polyethylene, polystyrene, and an acrylonitrile / styrene / butadiene copolymer. A long fiber reinforced polyamide resin exterior molded article as described.   The long-fiber reinforced polyamide resin exterior molded article according to any one of claims 1 to 6, wherein the reinforcing fibers are glass fibers having a diameter of 10 µm to 20 µm.   The long-fiber reinforced polyamide resin exterior molded body according to any one of claims 1 to 7, wherein the molded body is obtained by injection molding.   A long fiber reinforced polyamide resin exterior molded body according to any one of claims 1 to 8, wherein the bonnet, roof, hood, front panel, canopy, trunk lid, door panel, pillar, and similar automotive exterior panels Or the exterior molding for motor vehicles characterized by being the structure.   The long fiber reinforced polyamide resin exterior molded body has at least one non-reinforced resin layer laminated on the outer surface thereof, and has a long fiber reinforced layer / non-cross section in a cross section perpendicular to the laminated surface. The automotive exterior molded article according to claim 9, wherein the layer thickness ratio of the reinforced resin layer is 1.0 or more.   11. The automotive exterior molded article according to claim 10, wherein the non-reinforced resin is a resin of the same type as the long fiber reinforced polyamide resin, or an alloy containing the resin as a main component.   The automobile according to claim 10 or 11, wherein a decorative portion including characters, emblems and / or marks is enclosed between the long fiber reinforced molded body and the non-reinforced resin layer during the lamination. Exterior molded body.

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