JP5850675B2 - Nylon resin composition - Google Patents

Description

  The present invention relates to a nylon resin composition excellent in paintability, containing a pulverized product of fiber reinforced plastic, and a molded product formed by molding the same.

  Fiber reinforced plastics are used in a wide range of fields, including machinery, electrical / electronic equipment, building materials, vehicle parts / members, OA equipment, AV equipment, sports equipment, medical equipment, aircraft, and space equipment parts / members. Yes. Thermosetting resins such as epoxy resins are widely used as the matrix resin for fiber reinforced plastics. However, in the case of thermosetting resins, the working time is limited due to the curing life, and a curing reaction is involved. In general, the molding time is long, and after the molding is finished, the resin does not melt even when heated, and therefore cannot be reprocessed. Therefore, it has superior workability during processing compared to thermosetting resins, and uses thermoplastic resin that is remelted by heating as a matrix resin, and by adding reinforcing fibers to it, the mechanical strength of the thermoplastic resin is increased. .

  As such a thermoplastic resin, a thermoplastic resin such as a polyolefin resin, a polystyrene resin, a nylon resin, a polycarbonate resin, or a polyester resin is used, and as a reinforcing fiber, a glass fiber that is relatively inexpensive is frequently used. Of these, nylon resin is excellent in strength, heat resistance, solvent resistance, and the like, and is therefore widely used in the field of sporting goods such as automobile parts, machine parts, electrical equipment parts and fishing gear.

  However, the fiber reinforced plastic using nylon resin has some reinforced fibers on the surface, resulting in irregularities, so the surface quality of the molded product is often inferior, causing poor paintability. Nylon resin with good paintability is required for materials for automobile parts that require painting. In addition, when reinforcing fibers are blended with nylon resin, depending on the shape, after molding under heating, the nylon resin that forms the matrix shrinks while it is naturally cooled to room temperature, and the reinforcing fibers are not even on the surface of the molded product. Since the portion is exposed to form irregularities, there is a problem that the paintability is further deteriorated.

  For example, in Patent Document 1, the surface of a fiber reinforced plastic molded article made of carbon fiber and a thermoplastic resin has a predetermined surface roughness as a method for improving poor paintability due to unevenness on the surface of the fiber reinforced plastic. A method of polishing is disclosed. However, the method of polishing the surface requires an extra polishing step, which is not only expensive but also reduces productivity.

  Patent Document 2 discloses a method for eliminating irregularities on the surface of a fiber-reinforced plastic molded product by integrally heat-pressing resin powder on a surface portion of a fiber-reinforced plastic composed of a matrix resin and reinforcing fibers. Is disclosed. However, in this method, since the outermost surface layer is a resin layer that does not contain reinforcing fibers, the strength of the surface layer of the molded product is inferior.

JP 2002-067070 (Claim 11, [0015], etc.) JP 2007-331369 A (Claim 3 etc.)

  An object of the present invention is to provide a nylon resin composition that is excellent in paintability and that can use waste materials and waste products produced during production as a nylon resin and / or fiber reinforced plastic, and a molded product obtained by molding the same. It is to be.

  In order to solve the above problems, the present inventors have intensively studied and found that the above problems can be solved by blending a nylon resin with a fiber reinforced plastic pulverized product having a ratio of major axis / minor axis in a certain range. The headline, the present invention has been reached.

That is, the present invention is as follows.
(1) Nylon resin:
A pulverized product obtained by finely pulverizing a carbon fiber reinforced plastic using a thermosetting resin as a matrix resin, wherein the ratio of major axis / minor axis is 1.0 to 1.5, and the weight of the thermosetting resin / carbon fiber. A nylon resin composition comprising: a pulverized carbon fiber reinforced plastic having a ratio of 1/3 to 3/1: 15 to 90 parts by weight.
(2) The nylon resin composition according to (1), wherein the thermosetting resin is a resin mainly composed of an epoxy resin.
( 3 ) The nylon resin composition according to the above (1) or (2) , wherein at least one of the nylon resin and the fiber reinforced plastic pulverized material is used to recover and reuse waste materials or waste products at the time of production. object.
( 4 ) A molded product formed by molding the nylon resin composition according to any one of (1) to ( 3 ) above.

  According to the present invention, in addition to excellent paintability, a nylon resin molded product having excellent mechanical strength and high heat deformation temperature can be provided. In addition, as the nylon resin and / or fiber reinforced plastic, waste materials and waste products produced during production can be reused, so that a raw material is inexpensive, energy saving, and environmentally superior nylon resin composition can be provided.

  In the present invention, the details of the reason why the paintability of the molded product formed by molding the nylon resin composition is unclear, but the reinforcing fiber to be blended with the nylon resin enhances the adhesion with the thermosetting resin. In addition, since it is treated with a sizing agent or the like, it is presumed that the thermosetting resin is adhered to the reinforcing fiber in the pulverized product obtained by pulverizing the molded product after the thermosetting reaction. Therefore, the presence of the thermosetting resin suppresses the nylon resin melted at the time of molding the nylon resin composition from being shrunk by cooling after the molding is completed, and the reinforcing fiber is exposed to the surface of the molded product. It is presumed that the paintability is improved by preventing the presence of reinforcing fibers, and the mechanical properties such as mechanical strength and elastic modulus are improved.

  In the present invention, the nylon resin suitably used includes polycaproamide (nylon 6) resin, polyhexamethylene adipamide (nylon 66) resin, polytetramethylene adipamide (nylon 46) resin, polyhexamethylene Bacamide (nylon 610) resin, polyhexamethylene dodecamide (nylon 612) resin, polyundecanamide (nylon 11) resin, polydodecanamide (nylon 12) resin, polyhexamethylene terephthalamide (nylon 6T) resin, poly Hexamethylene isophthalamide (nylon 6I) resin, and mixtures thereof, or copolymer nylon resins having two or more components of these nylons (polycaproamide / polyhexamethylene adipamide copolymer (nylon 6/66) ), Polycapro Amide / polyhexamethylene terephthalamide copolymer (nylon 6 / 6T), polyhexamethylene adipamide / polyhexamethylene terephthalamide copolymer (nylon 66 / 6T), polyhexamethylene adipamide / polyhexamethylene isophthalamide copolymer (nylon) 66 / 6I), polyhexamethylene adipamide / polyhexamethylene isophthalamide / polycaproamide copolymer (nylon 66 / 6I / 6)) and the like.

  Among these, a nylon resin having a melting point of 200 ° C. or more is preferable from the viewpoint of heat resistance, and examples include nylon 6, nylon 66, nylon 610, nylon 6/66 copolymer, nylon 66 / 6I copolymer, and nylon 66 / 6I / 6 copolymer. Furthermore, nylon 6 and nylon 66 are preferable in terms of mechanical characteristics.

  The degree of polymerization of the nylon resin is not particularly limited as long as it can be subjected to normal molding. However, the relative viscosity measured at 25 ° C. in a 98% concentrated sulfuric acid solution of 1% by weight of nylon resin is in the range of 2 to 4. Are preferred.

  There is no restriction | limiting in particular in the form of nylon resin, A virgin pellet, a reproduction | regeneration pellet, a nylon resin ground material, etc. can be used. Among them, the pulverized nylon resin is not only excellent in uniform mixing with the pulverized fiber reinforced plastic compared to the nylon resin pellets, but also used products (hereinafter referred to as “waste products”) and waste materials from manufacturing. Even in the case where is used, pulverization can be performed regardless of the shape of the waste product or the waste material, and the particle size is easily controlled, which is preferable. The average particle size of the pulverized nylon resin is preferably 200 μm or less, more preferably 1 to 100 μm. When the particle size is less than 1 μm, it is difficult to uniformly mix with the pulverized fiber reinforced plastic.

  As the nylon resin pulverized product, a pulverized product obtained by pulverizing nylon fiber, nylon fiber fabric (woven fabric, knitted fabric, nonwoven fabric, braided string, etc.), nylon resin pellets, molded products of nylon resin, and the like can be used. Nylon fibers, nylon fiber fabrics, nylon resin pellets, and molded products of nylon resins may be used products or used materials collected in the manufacturing process of these products.

  When pulverizing nylon resin, it may be coarsely pulverized once and then finely pulverized to a predetermined size according to the shape and dimensions of the nylon resin to be pulverized by a known method. You may grind | pulverize to a predetermined magnitude | size. For coarse pulverization, a pulverizer such as a roll crusher, hammer crusher, cutter mill or the like can be used as appropriate.For fine pulverization, a rod mill, ball mill, vibration rod mill, vibration ball mill, roller mill, impact mill, stirring mill, etc. The pulverizer can be used as appropriate.

  It is important that the fiber-reinforced plastic pulverized product is a particle having a ratio of major axis / minor axis in the range of 1.0 to 1.5, where “major axis” is the longest length of the particle and “minor axis” is the particle. Is the shortest length. That is, particles having a major axis / minor axis ratio exceeding 1.5 are often elongated, and the fibrous reinforcing fibers exposed from the thermosetting resin are exposed on the surface of the nylon resin molded product. As a result, it becomes easy to form unevenness, and the paintability tends to deteriorate. The most preferable pulverized product is a spherical particle having a major axis / minor axis ratio in the range of 1.0 to 1.5.

  In addition, it is important that the weight ratio of the thermosetting resin / reinforcing fiber is in the range of 1/3 to 3/1 in the fiber reinforced plastic pulverized product. If the weight ratio is less than 1/3, Since it becomes difficult to prevent the fibers from being exposed to the surface of the molded product, it becomes difficult to improve the paintability of the nylon resin. On the other hand, when the weight ratio exceeds 3/1, a large amount of fiber reinforced plastic must be blended in order to secure a sufficient amount of reinforcing fibers to improve the strength and elastic modulus of the nylon resin composition. As a result, the kneadability and moldability of the nylon resin composition are likely to deteriorate. From the viewpoints of paintability and moldability, the weight ratio of thermosetting resin / reinforced fiber is more preferably in the range of 1/1 to 3/1, and still more preferably in the range of 1/1 to 2/1.

  The above pulverized fiber reinforced plastic is obtained by finely pulverizing fiber reinforced plastic using a thermosetting resin as a matrix resin, and the pulverized pulverized product may be used as it is. It is better to classify and use only those in the particle size range.

  The pulverized product of fiber reinforced plastic preferably has an average particle size of 200 μm or less, more preferably 1 to 70 μm. When the average particle size is less than 1 μm, not only the pulverization power is required, but also the pulverized product is easily aggregated due to electrostatic charging or the like, and the reinforcing effect of the nylon resin is small. On the other hand, if the average particle size is larger than 200 μm, the reinforcing fiber becomes longer, so the kneading time for uniformly mixing with the nylon resin becomes longer. There is a tendency to deteriorate.

As the reinforcing fibers of the fiber-reinforced plastic, specific gravity is small, high strength, from the viewpoint a high modulus, carbon fibers are preferred.

  The thermosetting resin that is a matrix resin includes epoxy resin, unsaturated polyester resin, vinyl ester resin, phenol resin, epoxy acrylate resin, urethane acrylate resin, phenoxy resin, alkyd resin, urethane resin, maleimide resin, cyanate resin. , Melamine resin, urea resin, and the like. A curing agent may be added to accelerate curing, and an elastomer or rubber component may be added to improve impact resistance. Among these, epoxy resins, unsaturated polyester resins, vinyl ester resins, phenol resins, and mixed resins thereof are preferable, and epoxy resins are particularly preferable from the viewpoint of rigidity and strength of a molded product.

  The length of the pulverized product and the length of the reinforced fiber in the fiber reinforced plastic pulverized product are not necessarily the same, but the reinforcing fiber is bundled like a fiber reinforced plastic formed by a pultrusion molding method or a filament winding molding method. The aggregated state is preferable, and the length of the reinforcing fiber is an indicator of the major axis of the pulverized product. Here, the pultrusion molding method is a molding method in which a bundle of reinforcing fiber filaments impregnated with a matrix resin such as an epoxy resin is cured by passing through a mold and then continuously drawn, and the filament winding molding method is This is a molding method in which a bundle of reinforcing fiber filaments impregnated with a matrix resin such as an epoxy resin is wound to a predetermined thickness, and then cured and demolded. When the reinforcing fibers are gathered in a bundle, the reinforcing fibers can be covered even with a small amount of the thermosetting resin, and the thermal shrinkage of the nylon resin can be more effectively suppressed.

  As the fiber reinforced plastic, a used product (waste product) of the molded product or a waste material generated in the manufacturing process of the fiber reinforced plastic molded product can be used.

  In the case of finely pulverizing fiber reinforced plastic, fiber reinforced plastic parts and disassembled / cut members can be pulverized using a high-speed collision destruction method, a shear mill method, a cutting method, or the like. In addition, in NEDO's “New Industry Support Type International Standard Development Project”, research on CFRP crushing technology and its use is being conducted in the study of “Standardization of recycled CFRP pulverized products”. (Yamaguchi, Kitano Journal of the Society of Materials Science, Japan Vol.57, No.7, pp.747-752, July 2008). In the case of fine pulverization, a high-speed collision pulverizer, a grinding pulverizer, or the like may be used to coarsely pulverize and then finely pulverize, or finely pulverize without coarse pulverization.

  The nylon resin composition of the present invention preferably contains 15 to 90 parts by weight, more preferably 20 to 70 parts by weight of a pulverized product of fiber reinforced plastic with respect to 100 parts by weight of nylon resin. When the content of the pulverized fiber reinforced plastic is less than 15 parts by weight, it is difficult to improve the paintability, and it is difficult to improve the mechanical strength and elastic modulus of the nylon resin. On the other hand, when the content of the pulverized fiber reinforced plastic exceeds 90 parts by weight, it becomes difficult to perform molding utilizing the characteristics of the thermoplastic resin such as correction by remelting after molding.

  In the present invention, it is preferable that at least one of the nylon resin and the fiber-reinforced plastic pulverized product is a recycled product such as a collected used product (waste product) or a waste material at the time of manufacture.

  When fiber-reinforced plastics are recycled, the content of reinforcing fibers in the thermosetting resin is often unknown at the stage of collecting used products and waste materials from production. In such a case, composition analysis of the reinforcing fibers in the thermosetting resin can be performed by a known method such as differential scanning calorimetry (DSC), pyrolysis gas chromatography, FTIR, or the like. The composition analysis can also be performed by a method in which the pulverized pieces of fiber reinforced plastic are removed by thermally decomposing the matrix resin at a high temperature of 700 to 800 ° C. in an inert gas atmosphere and taking out the reinforced fibers.

  In addition, the nylon resin composition of the present invention may contain hindered phenol-based antioxidants, benzophenone-based ultraviolet absorbers, decabromophenol, chlorinated polyethylene, condensed phosphate esters, and the like as necessary. An antibacterial agent such as a flame retardant, a silver-based antibacterial agent, a metal soap, a plasticizer, a pigment, a foaming agent, a lubricant, a processing aid, and the like can be blended.

  Moreover, 0-100 weight part of reinforcing materials can be mix | blended with a nylon resin composition. The amount and type of the reinforcing material may be appropriately selected according to the required mechanical properties, and is not particularly limited. Specific examples of such reinforcing materials include PAN-based and pitch-based carbon fibers, glass fibers, stainless steel fibers, aluminum fibers, brass fibers, aramid fibers, gypsum fibers, ceramic fibers, asbestos fibers, zirconia fibers, alumina fibers, silica fibers. And fibrous fillers such as titanium oxide fiber, silicon carbide fiber and basalt fiber, granular fillers such as talc, mica, calcium carbonate, wollastonite and silica, and other various fillers. These may be used in combination of a plurality of reinforcing materials.

  The nylon resin composition of the present invention is obtained by blending and melting a nylon resin and a fiber reinforced plastic pulverized product. After mixing and melting, after extruding with a strand die, it can be cooled and processed into a pellet-like shape that can be supplied to a molding machine using a pelletizer or the like, and pelletized using a hot cutter or granulator Can also be processed. It is also possible to prepare a master batch in which fiber reinforced plastic is kneaded into a resin at a high concentration and dilute it at the time of molding.

  The nylon resin composition of the present invention is subjected to various moldings such as injection molding, extrusion molding, hollow molding, pressure molding, film molding and press molding, and further subjected to secondary processing as necessary to obtain a molded product. In particular, a molded product formed by injection molding has excellent paintability.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely using an Example, this invention is not limited only to a following example. In addition, the measuring method of each characteristic value in the following examples and comparative examples is as follows.

[Paintability]
A 100 mm x 100 mm square plate (test piece) made by injection molding is coated with a polyester paint (manufactured by Kansai Paint Co., Ltd.) using a spray gun and baked at 140 ° C for 20 minutes. Then, the plate was left standing for 48 hours under conditions of 23 ° C.-50% RH to produce a test square plate, and the paintability was evaluated.
The evaluation of paintability was carried out using JIS K5600-5-6. That is, 25 squares were produced by making 6 cuts vertically and horizontally at 1 mm intervals on the coated surface of the test square plate using a cutter knife. A cellophane adhesive tape was affixed to the surface of the paint film cut into a grid shape so as to adhere about 75 mm, and was rubbed with a finger to adhere the adhesive tape to the coating film. Three minutes after the tape was attached, the end of the tape was held and the tape was peeled off at an angle of about 60 degrees on the surface of the coating film, and the number of cells (peeling number) of the peeled coating film was counted. It can be said that the smaller the number of peels, the better the paintability.

[Tensile strength and tensile elongation]
A tensile test piece having a width of 10 mm and a thickness of 3 mm of a dumbbell portion produced by injection molding was measured according to ISO 527-1.

[Bending strength and flexural modulus]
A bending test piece of 100 mm × 10 mm and thickness 3 mm produced by injection molding was measured according to ISO178.

[Charpy impact strength]
A test plate was prepared by adding a V-shaped notch to a molded plate 60 mm × 80 mm and 3 mm thick produced by injection molding, and measured according to ISO179.

[Rockwell hardness]
A square plate of 100 mm × 100 mm produced by injection molding and having a thickness of 2 mm was used as a test piece, and measurement was performed with a scale R (reference load 10 kgf, test load 60 kgf, steel ball diameter 1/2 inch).

[Heat deformation temperature]
Measurement was performed according to JISK7207 using a test piece of 100 mm × 10 mm and thickness 3 mm produced by injection molding.

[Ratio of major axis / minor axis of particle and particle diameter]
The ratio of the major axis / minor axis of the particles was measured using a scanning electron microscope. The particle size was measured using a particle size distribution meter (Shimadzu laser diffraction particle size distribution analyzer SALD3100).

Example 1
The waste material of nylon 6 resin generated during the production of nylon 6 resin was pulverized using a ball mill and classified to obtain a pulverized nylon 6 resin having a particle size of 30 to 60 μm. The relative viscosity of the obtained nylon 6 resin was 2.5. Separately, an automotive propeller shaft (carbon fiber: 43% by weight), which uses carbon fiber filaments manufactured by the filament winding method as reinforcing fibers and epoxy resin as a matrix resin, is roughly crushed to about 1 mm, and then used with a ball mill. The mixture was pulverized and classified to obtain a spherical pulverized product having a particle size of about 50 to 90 μm and a major axis / minor axis ratio of 1.3.

  Weighing 65 parts by weight of pulverized nylon 6 resin and 35 parts by weight of finely pulverized propeller shaft, mixing with a tumbler mixer, and then kneading and extrusion molding using a twin screw extruder (cylinder temperature 270 ° C.) The pellet material was manufactured by.

  Using the manufactured pellet material, a test piece was molded by an injection molding machine (cylinder temperature 270 ° C., mold temperature 80 ° C.), and performance was evaluated.

(Comparative Example 1)
Nylon 6 resin pulverized product of Example 1: 85 parts by weight, pulverized product of carbon fiber bundle (particle diameter: about 100 μm): 15 parts by weight were weighed, and a test piece was molded in the same manner as in Example 1 to evaluate performance. did.

(Comparative Example 2)
A test piece was molded in the same manner as in Comparative Example 1 except that a crushed glass fiber (particle diameter of about 15 μm) was used instead of the pulverized carbon fiber, and the performance was evaluated.
The crushed glass fiber was obtained by cutting a chopped strand of glass fiber into about 2 cm, pulverizing and classifying.

(Comparative Example 3)
A test piece was molded in the same manner as in Comparative Example 1 except that crushed aramid fiber (particle diameter: about 30 μm) was used instead of the pulverized carbon fiber, and performance was evaluated.
The pulverized aramid fiber was obtained by cutting the short fibers of para-aramid fiber, pulverizing and classifying.

(Comparative Example 4)
The waste material of nylon 6 resin generated during the production of nylon 6 resin was pulverized using a ball mill and classified to obtain a pulverized nylon 6 resin having a particle size of 30 to 60 μm. The relative viscosity of the obtained nylon 6 resin was 2.5. A car propeller shaft (carbon fiber: 43% by weight) using carbon fiber cloth as reinforcing fiber and epoxy resin as matrix resin is coarsely pulverized with a vertical pulverizer, then again applied to a pulverizer and classified to increase the length. A fibrous pulverized product having a length of 1 to 2 mm was obtained. A pellet material was manufactured by kneading and extruding using the same method as in Example 1.

  The performance evaluation results of Example 1 and Comparative Examples 1 to 4 are summarized in Table 1.

  From the results shown in Table 1, the molded product of the nylon resin composition (comparative examples 1 to 3) composed of nylon 6 and reinforcing fiber not containing epoxy resin has poor adhesion of the paint to the molded product surface, and most The molded product of the nylon resin composition of the present invention containing an epoxy resin (Example 1), which is a pulverized product of fiber reinforced plastic, has no paint peeling and good paintability. You can see that. Moreover, the nylon resin composition of the present invention has a mechanical performance (tensile strength, bending strength and bending strength) as compared with the molded product of the nylon resin composition consisting only of nylon 6 and reinforcing fibers of Comparative Examples 1 to 3. It can be seen that it exhibits excellent performance in terms of elastic modulus and thermal performance (thermal deformation temperature).

  Even when a pulverized product of fiber reinforced plastic was blended, when the pulverized product was fibrous (Comparative Example 4), the paintability was poor.

  Since the nylon resin composition of the present invention is excellent in mechanical strength and elastic modulus, and can give a molded product exhibiting good paintability, it can be used for automobile interior / exterior materials, architectural interior materials, mobile phones, PCs, etc. It can be particularly preferably used in fields where strength and aesthetics are required, such as the housing of the above.

Claims (4)

Nylon resin: 100 parts by weight
A pulverized product obtained by finely pulverizing a carbon fiber reinforced plastic using a thermosetting resin as a matrix resin, wherein the ratio of major axis / minor axis is 1.0 to 1.5, and the weight of the thermosetting resin / carbon fiber. Carbon fiber reinforced plastic pulverized product having a ratio of 1/3 to 3/1: 15 to 90 parts by weight,
A nylon resin composition comprising:   The nylon resin composition according to claim 1, wherein the thermosetting resin is a resin mainly composed of an epoxy resin. The nylon resin composition according to claim 1 or 2 , wherein at least one of the nylon resin and the fiber-reinforced plastic pulverized material is used for collecting and reusing waste materials or waste products at the time of production. The molded article formed by shape | molding the nylon resin composition in any one of Claims 1-3 .