JP2012116916A - Carbon fiber-reinforced polypropylene resin molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbon fiber-reinforced polypropylene resin molded article that has good flame retardancy and moldability, good interfacial adhesion between a polypropylene resin and carbon fibers, and excellent mechanical characteristics.SOLUTION: The carbon fiber-reinforced polypropylene resin molded article includes (A) 40-94.5 wt.% of a polypropylene resin, (B) 5-40 wt.% of carbon fibers, and (C) 0.5-20 wt.% of a flame retardant. In the molded article, (B) the carbon fibers are bent.

Description

The present invention relates to a carbon fiber reinforced polypropylene resin molded article, and particularly to a carbon fiber reinforced polypropylene resin molded article excellent in good flame retardancy and mechanical properties.

  Compositions composed of reinforcing fibers and thermoplastic resins are widely used in sports equipment applications, aerospace applications and general industrial applications because they are lightweight and have excellent mechanical properties. Reinforcing fibers used in these fiber-reinforced thermoplastic resin compositions reinforce molded products in various forms depending on the intended use. These reinforcing fibers include metal fibers such as aluminum fibers and stainless fibers, organic fibers such as aramid fibers, inorganic fibers such as silicon carbide fibers, and carbon fibers. However, specific strength, specific rigidity and light weight are used. From the viewpoint of balance of properties, carbon fibers are preferred, and among them, polyacrylonitrile-based carbon fibers are suitably used.

  As a matrix resin, a lightweight olefin resin, in particular, a polypropylene resin has been used, and a carbon fiber reinforced polypropylene resin has attracted attention as a material for a transport machine such as an automobile.

  On the other hand, parts constituting electric and electronic devices and body structure parts are required to have high flame resistance while achieving high strength and high rigidity as well as weight reduction. However, since the propylene resin is vulnerable to high heat and is a flammable resin, it has been difficult to obtain a molded product having excellent flame retardancy. In particular, studies on imparting flame retardancy for carbon fiber reinforced polypropylene resins have been insufficient.

  Patent Document 1 discloses a resin composition comprising a polyolefin resin, an elastomer, and a carbon fiber sized by a polyfunctional compound, but is not particularly referred to the flame retardancy of the resin composition. .

Patent Document 2 discloses a resin composition that exhibits excellent flame retardancy by blending a resin, carbon fiber, and a flame retardant, but specifically imparts flame retardancy as a polypropylene resin molded article. This is not disclosed.
Patent Document 3 discloses a polyamide-based resin composition composed of an organic phosphorus-based flame retardant and reinforcing long fibers, but does not mention anything about the flame retardancy of polypropylene resin.

  Thus, in the prior art, an effective method for adding flame retardancy to a carbon fiber reinforced polypropylene resin has not been clarified, and the development of a long fiber reinforced propylene resin molded product excellent in flame retardancy has been desired.

JP 2010-248482 A JP 2002-226713 A JP 2010-31257 A

  An object of this invention is to provide the carbon fiber reinforced polypropylene resin molded product excellent in the flame retardance in view of the background of a prior art.

As a result of intensive studies to achieve the above object, the present inventors have found the following carbon fiber reinforced polypropylene resin molded product that can achieve the above-mentioned problems.
(1) (A) 40-94.5% by weight of polypropylene resin, (B) 5-40% by weight of carbon fiber, and (C), where the total of (A), (B) and (C) is 100% by weight A carbon fiber reinforced polypropylene resin molded product containing 0.5 to 20% by weight of a flame retardant, wherein (B) the carbon fiber is bent and present in the molded product. .
(2) In the molded product, when the linear distance between both ends of the (B) carbon fiber is L1, the fiber length is L2, and the ratio L2 / L1 is the bending degree, the weight average of the bending degree is 1.2 or more. The carbon fiber reinforced polypropylene resin molded product according to (1), wherein
(3) The carbon fiber-reinforced polypropylene resin molded product according to (1) or (2), wherein the carbon fiber is sized with a polyfunctional compound.
(4) In any one of (1) to (3), 0.01 to 30 parts by weight of (D) elastomer is contained with respect to 100 parts by weight of the total of (A), (B) and (C). Carbon fiber reinforced propylene resin molded product.
(5) Resin pellets containing (A) polypropylene resin, (B) carbon fiber, and (C) flame retardant, and (B) carbon fiber fiber length is substantially equal to the pellet length. The carbon fiber reinforced polypropylene resin molded product according to any one of (1) to (4), which is obtained by molding.

  The carbon fiber reinforced polypropylene resin molded product of the present invention has flame retardancy, excellent moldability, and good interfacial adhesion between the carbon fiber and the polypropylene resin, so that mechanical properties such as bending properties and impact resistance properties are obtained. Excellent molded product. Moreover, since the polypropylene resin is used, a molded product having excellent lightness can be obtained.

  In addition, when the bent carbon fiber in the molded product is burned, the bending is released and the effect of improving the flame retardancy is obtained, so that the addition of a small amount of flame retardant can provide flame retardance higher than that of the prior art. it can.

  The carbon fiber reinforced propylene resin composition of the present invention is extremely useful for various parts and members such as electrical / electronic equipment, OA equipment, home appliances, or automobile parts, internal members, and casings.

It is a schematic diagram which shows the bending degree of the carbon fiber in the molded article of this invention. It is a schematic diagram in case the bending degree of the carbon fiber in a molded article is 1.

  This invention is comprised from the following structural component (A) polypropylene resin, (B) carbon fiber, and (C) a flame retardant. First, these components will be described.

  Examples of the (A) polypropylene resin of the present invention include a homopolymer of propylene or a copolymer of propylene and at least one α-olefin, conjugated diene, non-conjugated diene and the like.

  Examples of the monomer repeating unit constituting the α-olefin include ethylene, 1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl- 2-12 carbon atoms excluding propylene such as 1-hexene, 4,4 dimethyl-1-hexene, 1-nonene, 1-octene, 1-heptene, 1-hexene, 1-decene, 1-undecene and 1-dodecene Examples of the monomer repeating unit constituting the α-olefin, conjugated diene, and non-conjugated diene include butadiene, ethylidene norbornene, dicyclopentadiene, 1,5-hexadiene, and the like. One type or two or more types can be selected.

  (A) As a skeleton structure of polypropylene resin, a homopolymer of propylene, one or two or more random or block copolymers of propylene and the above-mentioned other monomers, or other thermoplastic monomers And a copolymer thereof. For example, polypropylene, ethylene / propylene copolymer, propylene / 1-butene copolymer, ethylene / propylene / 1-butene copolymer, and the like are preferable.

  In general, a propylene homopolymer is used when rigidity is required, and one or two or more random or block polypropylenes of propylene and the other monomers are used when impact characteristics are required. .

  The (A) polypropylene resin is preferably a modified polypropylene resin from the viewpoint of improving the mechanical properties of the obtained molded product. An acid-modified polypropylene resin is preferred, and a polypropylene resin having a carboxylic acid and / or salt group bonded to a polymer chain. The acid-modified polypropylene resin can be obtained by various methods. For example, the (A) polypropylene resin has a neutralized or non-neutralized monomer having a carboxylic acid group, and / or A monomer having a carboxylic acid ester that has been converted to saponified or not saponified can be obtained by graft polymerization.

  Here, as the monomer having a neutralized or non-neutralized carboxylic acid group, and the monomer having a saponified or unsaponified carboxylic acid ester group, for example, ethylene System unsaturated carboxylic acids and anhydrides thereof, and esters thereof, and compounds having unsaturated vinyl groups other than olefins.

  Examples of the ethylenically unsaturated carboxylic acid include (meth) acrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, and the like. Examples thereof include (endocis-bicyclo [2.2.1] hept-5-ene-2,3-dicarboxylic acid), maleic anhydride, citraconic anhydride and the like.

  As monomers having unsaturated vinyl groups other than olefins, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, tert -Butyl (meth) acrylate, n-amyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, dodecyl (Meth) acrylate, octadecyl (meth) acrylate, stearyl (meth) acrylate, tridecyl (meth) acrylate, lauroyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, (Meth) acrylic acid such as nyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate Esters, hydroxyethyl acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl acrylate, lactone-modified hydroxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl acrylate, etc. Hydroxyl group-containing vinyls, epoxy group-containing vinyls such as glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, vinyl isocyanate, isopropenyl Isocyanate group-containing vinyls such as cyanate, aromatic vinyls such as styrene, α-methylstyrene, vinyltoluene, and t-butylstyrene, acrylamide, methacrylamide, N-methylolmethacrylamide, N-methylolacrylamide, diacetoneacrylamide Amides such as maleic acid amide, vinyl esters such as vinyl acetate and vinyl propionate, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (methacrylate, N, N-dimethylaminopropyl) Aminoalkyl (meta) such as (meth) acrylate, N, N-dipropylaminoethyl (meth) acrylate, N, N-dibutylaminoethyl (meth) acrylate, N, N-dihydroxyethylaminoethyl (meth) acrylate Acrylates, styrene sulfonic acid, sodium styrene sulfonate, unsaturated sulfonic acids such as 2-acrylamido-2-methylpropane sulfonic acid, mono (2-methacryloyloxyethyl) acid phosphate, mono (2-acryloyloxyethyl) And unsaturated phosphates such as acid phosphates.

  These monomers can be used alone or in combination of two or more. Of these, acid anhydrides are preferable, and maleic anhydride is more preferable.

  (A) When the polypropylene resin is a polypropylene resin having a carboxylic acid and / or salt group bonded to the polymer chain, the mechanical properties of the resin are kept high, and the raw material cost is taken into consideration. It is preferable to use a mixture with an unmodified polypropylene resin. Specifically, 5 to 50% by mass of a propylene resin (A-1) having a carboxylic acid and / or salt group bonded to a polymer chain, and a propylene resin having no carboxylic acid and / or salt group thereof (A-2) It is preferable to have 50-95 mass%. More preferably, the component (A-1) is 5-45% by mass, the component (A-2) is 55-95% by mass, more preferably the component (A-1) is 5-35% by mass, and the component (A-2). ) Is 65 to 95% by mass.

  Examples of the carbon fiber (B) used in the present invention include PAN-based, pitch-based and rayon-based carbon fibers. From the viewpoint of the balance between the strength and elastic modulus of the obtained molded product, PAN-based carbon fibers are more preferable. For the purpose of imparting conductivity, reinforcing fibers coated with a metal such as nickel, copper, or ytterbium can also be used.

  Further, as the carbon fiber, the surface oxygen concentration ratio [O / C], which is the ratio of the number of atoms of oxygen (O) and carbon (C) on the fiber surface measured by X-ray photoelectron spectroscopy, is 0.05-0. 5 is preferable, more preferably 0.08 to 0.4, and still more preferably 0.1 to 0.3. When the surface oxygen concentration ratio is 0.05 or more, the functional group amount on the surface of the carbon fiber can be secured, and a stronger adhesion to the thermoplastic resin can be obtained. Moreover, although there is no restriction | limiting in particular in the upper limit of surface oxygen concentration ratio, Generally it can be illustrated to 0.5 or less from the balance of the handleability of carbon fiber, and productivity.

  The surface oxygen concentration ratio of the carbon fiber is determined by X-ray photoelectron spectroscopy according to the following procedure. First, after cutting the carbon fiber bundle from which the sizing agent and the like adhering to the carbon fiber surface with a solvent was cut to 20 mm and spreading and arranging on a copper sample support base, using A1Kα1,2 as the X-ray source, The sample chamber is kept at 1 × 10 8 Torr. The kinetic energy value (KE) of the main peak of C1s is adjusted to 1202 eV as a peak correction value associated with charging during measurement. The C1s peak area is expressed as K.S. E. Is obtained by drawing a straight base line in the range of 1191 to 1205 eV. The O1s peak area is expressed as K.I. E. Is obtained by drawing a straight base line in the range of 947 to 959 eV.

  Here, the surface oxygen concentration ratio is calculated as an atomic ratio by using a sensitivity correction value unique to the apparatus from the ratio of the O1s peak area to the C1s peak area. As an X-ray photoelectron spectroscopy apparatus, model ES-200 manufactured by Kokusai Electric Inc. is used, and the sensitivity correction value is set to 1.74.

  The means for controlling the surface oxygen concentration ratio [O / C] to 0.05 to 0.5 is not particularly limited. For example, techniques such as electrolytic oxidation, chemical oxidation, and vapor phase oxidation are used. Among these, electrolytic oxidation treatment is preferable.

  The average fiber diameter of the carbon fibers is not particularly limited, but is preferably in the range of 1 to 20 μm and preferably in the range of 3 to 15 μm from the viewpoint of the mechanical properties and surface appearance of the obtained molded product. More preferred. There is no restriction | limiting in particular in the single yarn number at the time of setting it as a reinforced fiber bundle, It can use within the range of 100-350,000, It is especially used within the range of 1,000-250,000. preferable. Further, from the viewpoint of productivity of reinforcing fibers, those having a large number of single yarns are preferable, and it is preferable to use them within a range of 20,000 to 100,000.

  The (B) carbon fiber used in the present invention is preferably a carbon fiber sizing-treated with a polyfunctional compound. Although it does not specifically limit as a polyfunctional compound, The compound which has 2 or more functional groups, such as an epoxy group, a urethane group, an amino group, and a carboxyl group, can be used, and these are used together 1 type or 2 types or more. May be. When the number of functional groups is less than 2, the adhesiveness between the reinforcing fiber and the matrix resin cannot be sufficiently exhibited. Therefore, the number of functional groups is essential to be 2 or more, more preferably 3 or more.

  Specific examples of the compound include polyfunctional epoxy resins, acid-modified polypropylene, and neutralized products of acid-modified polypropylene.

  Examples of the polyfunctional epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, aliphatic epoxy resin, phenol novolac type epoxy resin and the like. Among these, an aliphatic epoxy resin that easily exhibits adhesiveness with the matrix resin is preferable. In general, when an epoxy resin has a large number of epoxy groups, the crosslinking density after the crosslinking reaction becomes high, and therefore it tends to be a structure with low toughness, and even if it exists between the reinforcing fiber and the matrix resin, it is fragile. It is easy to peel off and the strength of the fiber reinforced composite material may not be expressed. On the other hand, since the aliphatic epoxy resin has a flexible skeleton, it tends to have a high toughness structure even if the crosslinking density is high. When it exists between a reinforced fiber and matrix resin, in order to make it soft and it is hard to peel, it is easy to improve the intensity | strength of a fiber reinforced composite material, and preferable. Specific examples of the aliphatic epoxy resin include, for example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1,4-diglycidyl ether compound, and 1,4- Examples include butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, and polyalkylene glycol diglycidyl ether. Also, in the polyglycidyl ether compound, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, arabitol polyglycidyl ether, trimethylolpropane polyglycidyl ether, trimethylolpropane Examples thereof include glycidyl ethers, pentaerythritol polyglycidyl ethers, polyglycidyl ethers of aliphatic polyhydric alcohols, and the like.

  Among the aliphatic epoxy resins, an aliphatic polyglycidyl ether compound having many highly reactive glycidyl groups is preferable. Among these, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyethylene glycol glycidyl ether, and polypropylene glycol glycidyl ether are more preferable. Aliphatic polyglycidyl ether compounds are preferred because they have a good balance of flexibility, crosslink density, and compatibility with the matrix resin and effectively improve adhesion.

  Acid-modified polypropylene, neutralized product of acid-modified polypropylene, for example, a polymer main chain mainly composed of hydrocarbon such as propylene, a carboxyl group formed by unsaturated carboxylic acid, or a metal salt or ammonium salt thereof And having a side chain containing. The polymer main chain may be a random copolymer obtained by copolymerizing propylene and an unsaturated carboxylic acid, or may be a graft copolymer obtained by grafting an unsaturated carboxylic acid on propylene. Further, it may be copolymerized with a copolymerizable copolymer component such as α-olefin, conjugated diene, non-conjugated diene or 1-butene. Acid-modified polypropylene and neutralized product of acid-modified polypropylene are flexible while having many functional groups in one molecule, and since the skeleton is the same polypropylene as the matrix resin, compatibility with the matrix resin is high. It is preferable because it is easy to improve adhesiveness.

  Unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, isocrotonic acid, citraconic acid, allyl succinic acid, mesaconic acid, glutaconic acid, nadic acid, methyl nadic acid, tetrahydrophthalic acid And methyltetrahydrophthalic acid. In particular, maleic acid, acrylic acid, and methacrylic acid are preferable because they are easily copolymerized. Only one type of unsaturated carboxylic acid may be used for copolymerization with propylene or graft copolymerization with propylene, or two or more types of unsaturated carboxylic acids may be used. In addition, in the neutralized product of acid-modified polypropylene, at least some of the carboxyl groups are neutralized with metal cations such as Na, K, Li, Mg, Zn, Ca, Cu, Fe, Ba, Al, or ammonium ions. It is preferable.

Further, since it has two or more functional groups, the total amount is 0.05 to 5 mmol in terms of a group represented by -C (= O) -O- per 1 g of acid-modified polypropylene or neutralized product of acid-modified polypropylene. It is preferable that it is equivalent. More preferably, it is 0.1-4 mmol equivalent, More preferably, it is 0.3-3 mmol equivalent. As a method for analyzing the content of the carboxylate as described above, a method of quantitatively detecting a metal species forming a salt by ICP emission analysis, or a method using IR, NMR, elemental analysis, etc. A method for quantifying the carbonyl carbon of the acid salt is mentioned. When the total amount in terms of a group represented by —C (═O) —O— is 0.05 mmol equivalent or less, the adhesiveness tends to be difficult to be exhibited, and when it is 5 mmol equivalent or more, the acid-modified polypropylene or the acid-modified polypropylene The neutralized product may become brittle.

  By applying the polyfunctional compound to the reinforcing fiber as a sizing agent, even if the addition amount is small, it effectively adapts to the surface properties such as functional groups on the surface of the reinforcing fiber and improves the adhesive properties and composite overall properties. Can be made. In addition, it improves bundling, bending resistance, and abrasion resistance, and suppresses the occurrence of fluff and yarn breakage in the high-order processing step. It can also improve the high-order workability as a so-called paste and bundling agent. it can.

  The sizing agent adhesion amount is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.05% by mass or more and 5% by mass or less, and more preferably 0.1% by mass or more and 2% by mass with respect to the mass of the reinforcing fiber alone. % Or less is more preferable. If it is 0.01% by mass or less, the effect of improving adhesiveness is hardly exhibited, and if it is 10% by mass or more, the physical properties of the matrix resin may be lowered.

  The sizing agent also includes other components such as bisphenol-type epoxy compounds, linear low molecular weight epoxy compounds, polyethylene glycol, polyurethane, polyester, emulsifiers and surfactants, viscosity adjustment, improved scratch resistance, improved fuzz resistance, It may be added for the purpose of improving the focusing property and improving the high-order workability.

  There are no particular restrictions on the means for applying the sizing agent, but there are, for example, a method of immersing in a sizing liquid through a roller, a method of contacting a roller to which the sizing liquid is adhered, and a method of spraying the sizing liquid in a mist form. . Moreover, although either a batch type or a continuous type may be sufficient, the continuous type which has good productivity and small variations is preferable. At this time, it is preferable to control the sizing solution concentration, temperature, yarn tension, and the like so that the amount of the sizing agent active ingredient attached to the reinforcing fiber is uniformly attached within an appropriate range. Moreover, it is more preferable to vibrate the reinforcing fiber with ultrasonic waves when applying the sizing agent.

  The drying temperature and drying time should be adjusted according to the amount of the compound attached, but the time required for complete removal of the solvent used to apply the sizing agent and drying is shortened, while the thermal deterioration of the sizing agent is prevented and sizing is performed. From the viewpoint of preventing the reinforcing fiber bundle formed of the treated carbon fiber (B) from becoming hard and deteriorating the spreadability of the bundle, the drying temperature is preferably 150 ° C. or higher and 350 ° C. or lower. More preferably, the temperature is 180 ° C. or higher and 250 ° C. or lower.

  Examples of the solvent used for the sizing agent include water, methanol, ethanol, dimethylformamide, dimethylacetamide, and acetone. Water is preferable from the viewpoint of easy handling and disaster prevention. Accordingly, when a compound insoluble or hardly soluble in water is used as a sizing agent, it is preferable to add an emulsifier and a surfactant and disperse in water. Specifically, as an emulsifier and a surfactant, styrene-maleic anhydride copolymer, olefin-maleic anhydride copolymer, formalin condensate of naphthalene sulfonate, anionic emulsifier such as sodium polyacrylate, Nonionic emulsifiers such as cationic emulsifiers such as polyethyleneimine and polyvinylimidazoline, nonylphenol ethylene oxide adducts, polyvinyl alcohol, polyoxyethylene ether ester copolymers, sorbitan ester ethyl oxide adducts, etc. can be used. A nonionic emulsifier having a small size is preferable because it hardly inhibits the adhesive effect of the polyfunctional compound.

  The (B) carbon fiber of the present invention needs to be bent in the molded product. Here, “bent” means that the carbon fiber is not broken and is not in a straight line. More specifically, when the linear distance between both ends of one carbon fiber is L1, and the fiber length is L2, the ratio L2 / L1 can be defined as the degree of bending. When the bending degree is 1, it is a straight line, and it can be said that the bending degree is higher as the bending degree exceeds 1 and becomes a larger value. As a specific quantification method, an X-ray CT apparatus is used for the molded product, the spatial position of the carbon fiber in the molded product is specified by specific fracture, and L1 and L2 are specified by obtaining the spatial coordinates of the end. be able to. L1 and L2 are obtained for a minimum of 500 carbon fibers in an arbitrary space of the molded product, and the weight average is obtained to obtain the degree of bending of the molded product. The weight average is preferably 1.2 or more, more preferably 1.4 or more. When the weight average value of L2 / L1 is less than 1.2, the flame retardancy may decrease, which is not preferable. Since the carbon fiber is bent in the molded product, the bending strain of the carbon fiber is released when the resin melts during combustion, and the carbon fiber appears on the molten surface, which synergizes with the flame retardant. It can act to increase flame retardancy.

  There is no particular limitation on the fiber length of the (B) carbon fiber in the molded article of the present invention, but the weight average fiber length is 0.4 to 2.0 mm, preferably 0.5 to 1.5 mm. . If the fiber length is less than 0.4 mm, it is difficult to bend in the molded product, and if the fiber length exceeds 2.0 mm, there is a problem in molding processability.

  The method of bending the carbon fiber (B) of the present invention in the molded product is not particularly limited, but it is important to propagate the orientation of the polypropylene resin in molding the molded product to the carbon fiber. For this reason, it is preferable that the carbon fiber is sized with a polyfunctional compound. Moreover, it is preferable that the resin pressure at the time of molding is high, such as the shape of the molded product is a long flow length and a small thickness of the molded product. In addition, the presence of the flame retardant component (C) is also effective for enhancing flexibility.

  As the flame retardant (C) used in the present invention, known flame retardants can be used, and halogen compounds, antimony compounds, phosphorus compounds, nitrogen compounds, silicone compounds, fluorine compounds, metal hydroxides, boron compounds, etc. Can be mentioned.

  Such a phosphorus compound is not particularly limited as long as it is an organic or inorganic compound containing phosphorus, and examples thereof include ammonium polyphosphate, polyphosphazene, phosphate, phosphonate, phosphinate, phosphine oxide, and red phosphorus. You may use or use together. Of these, ammonium polyphosphate, aromatic phosphate, and red phosphorus are preferable.

  Examples of the metal hydroxide include magnesium hydroxide and aluminum hydroxide.

  Examples of the boron compound include zinc borate, and a combination with a phosphorus compound or a nitrogen compound can also be preferably used.

  In addition to (A) to (C), it is preferable to further have (D) an elastomer. In the present invention, the elastomer generally contains a polymer having a glass transition temperature lower than room temperature, and a part of the molecules are constrained to each other by covalent bond, ionic bond, van der Waals force, entanglement, etc. It is a polymer.

  Examples of (D) elastomers include olefin-based elastomers, styrene-based elastomers, urethane-based elastomers, ester-based elastomers, and amide-based elastomers. Specific examples of olefin-based elastomers include ethylene-α-olefin copolymers, ethylene. -Ethylene-propylene non-conjugated diene terpolymer such as propylene-ethylidene norbornene copolymer and ethylene-propylene-hexadiene copolymer. Specific examples of styrene elastomers include styrene-butadiene, styrene-isoprene-styrene, styrene-butadiene-styrene, styrene-ethylene-butadiene-styrene, styrene-ethylene-propylene-styrene random copolymers, and blocks. Examples thereof include a copolymer, a hydrogenated product of the block copolymer, and an acrylonitrile-butadiene-styrene copolymer. Among these, ethylene-α-olefin copolymers as olefin-based elastomers are preferable because they have good compatibility with polypropylene and can effectively improve impact resistance.

  These elastomers can be used alone or in combination of two or more.

  Moreover, although the SP value of (A) polypropylene resin depends on the type, this value is usually about 8 to 9, so that the SP value of (D) elastomer is preferably 6.5 to 9.5. 7-9 are more preferable. When the SP value of (D) is not in the range of 6.5 to 9.5, it tends to be incompatible with (A) polypropylene resin, and when not compatible, the viscosity of the polypropylene resin composition tends to increase. , The moldability may decrease.

  Further, the polypropylene resin molded article of the present invention may contain other fillers and additives within a range not impairing the object of the present invention. Examples of these include inorganic fillers, conductivity imparting agents, crystal nucleating agents, ultraviolet absorbers, antioxidants, vibration damping agents, antibacterial agents, insect repellents, deodorants, coloring inhibitors, heat stabilizers, mold release agents Agents, antistatic agents, plasticizers, lubricants, colorants, pigments, dyes, foaming agents, antifoaming agents, or coupling agents.

  The polypropylene resin molded article of the present invention comprises at least (A) a polypropylene resin, (B) carbon fiber, and (C) a flame retardant. Of these, the total of (A), (B) and (C) is 100% by weight, and (A) polypropylene resin is 40 to 94.5% by weight, preferably 50 to 90% by weight, more preferably 60 to 80%. % By weight. If it is less than 40% by weight, the moldability tends to decrease, and if it exceeds 94.5%, the flame retardancy tends to decrease.

  (B) Carbon fiber is 5 to 40 weight%, Preferably it is 10 to 35 weight%, More preferably, it is 15 to 30 weight%. (B) If the carbon fiber is less than 5% by weight, the mechanical properties of the molded product may be insufficient, and if it exceeds 40% by weight, the fluidity may be reduced during molding such as injection molding.

  (C) The flame retardant is 0.5 to 20% by weight, preferably 2 to 15% by weight, more preferably 5 to 12% by weight. (C) When the flame retardant is less than 0.5% by weight, the flame retardancy is lowered, and when it exceeds 20% by weight, the moldability and mechanical properties may be lowered.

  Moreover, when the component (D) is contained in addition to the components (A) to (C), the (D) elastomer is 0.01 to 30 with respect to 100 parts by weight of the total of (A) to (C). Parts by weight, preferably 0.5 to 20 parts by weight, more preferably 1 to 15 parts by weight. (D) When an elastomer exceeds 30 weight part, the mechanical characteristics of a molded article may be reduced.

  As the form of the molding material used for the polypropylene resin molded product of the present invention, pellets, stampable sheets, prepregs, SMC, BMC, etc. can be used, but the most desirable molding material is pellets used for injection molding. is there. The pellet generally refers to a pellet obtained by kneading a desired amount of resin, a filler, a chopped yarn of fibers, or continuous fibers in an extruder, and extruding and pelletizing. In particular, when carbon fiber is used, the above-mentioned pellet is shorter in the fiber length in the pellet than the length in the longitudinal direction of the pellet, but the pellet in the present invention includes a long fiber pellet, which is preferable. Can be used.

  Such a long fiber pellet is, as shown in Japanese Patent Publication No. 63-37694, in which fibers are arranged substantially parallel to the longitudinal direction of the pellet, and the fiber length in the pellet is equal to or longer than the pellet length. It points to something. In this case, the resin may be impregnated in the fiber bundle or may be coated on the fiber bundle. In particular, in the case of long fiber pellets coated with a resin, the fiber bundle may be impregnated in advance with a resin having the same viscosity as that of the coated fiber or a resin having a lower viscosity (or lower molecular weight) than the coated resin.

  Examples of the molding method include press molding, transfer molding, injection molding, and combinations thereof. Since the carbon fibers are bent in the molded product, molding is performed so that the resin composition is oriented during molding. It is preferable to do. From this viewpoint, injection molding is preferably used.

  As a molded article, it is suitable for automobile parts such as various modules such as an instrument panel, a door beam, an under cover, a lamp housing, a pedal housing, a radiator support, a spare tire cover, and a front end. In addition, home / office electrical product parts such as telephones, facsimiles, VTRs, copiers, televisions, microwave ovens, audio equipment, toiletries, refrigerators, air conditioners, and the like are also included. Further, there are a housing used for a personal computer, a mobile phone and the like, and a member for electric / electronic equipment represented by a keyboard support which is a member for supporting a keyboard inside the personal computer. When carbon fiber having conductivity is used as the reinforcing fiber, such a member for electrical / electronic equipment is more preferable because it imparts electromagnetic wave shielding properties.

  Hereinafter, the present invention will be described in more detail with reference to examples.

(1) Flame retardancy FMVSS No. In accordance with 302 fire spread test, using a square plate (100 mm x 150 mm x 3 mmt), a 3 cm flame of a gas burner was applied to the end of the square plate until it ignited, and the fire spread from the end to the 50 mm mark The speed was measured.
The fire spread rate was judged according to the following criteria, and ◎ and ○ were accepted.
A: Self-extinguishment within 3 minutes after flame contact ignition ○: Self-extinguishment within 7 minutes after flame contact ignition Δ: Ignition with flame contact for 31 seconds to 60 seconds x: Ignition with flame contact for 15 seconds to 30 seconds

(2) Bending test In accordance with ISO 178, using a three-point bending test jig (indenter radius 5 mm), the fulcrum distance is set to 64 mm, and the bending strength and bending elastic modulus are measured under test conditions of a test speed of 2 mm / min. did. As a testing machine, an “Instron (registered trademark)” universal testing machine type 5566 (manufactured by Instron) was used.

(3) Impact test Based on ISO 179, a Charpy impact test with a processed notch was performed. As the Charpy tester, RESIL25 manufactured by CEAST was used. As the test piece size, a test piece having a thickness of 4 mm, a width of 10 mm, and a length of 80 mm was used. The test temperature was normal temperature (23 ° C.) and low temperature (−40 ° C.). The temperature adjustment was carried out using a PU-1K type thermostat made by Tabai, and allowed to stand for 40 min or more in the thermostat to make the temperature constant, and then the test was performed.

(4) Flexion degree of carbon fiber As an X-ray CT analysis apparatus, TDM-1000IS manufactured by Yamato Material Co., Ltd. was used. The center part of the square plate molded product for the flame retardancy test was cut into a 1 cm × 1 cm square and subjected to X-ray CT analysis. Further, based on the results of X-ray CT analysis, fiber length measurement was performed using a fiber length measurement program in combination. Thus, the linear distance between the fiber ends: L1, and the actual fiber length: L2 were measured, and the measurement was carried out on a minimum of 500 fibers.

Reference Example 1 Carbon fiber Spinning, baking treatment, and surface oxidation treatment were carried out from a copolymer containing polyacrylonitrile as a main component to obtain continuous carbon fibers having a total number of 24,000 single yarns. The characteristics of this continuous carbon fiber were as follows.
Single fiber diameter: 7μm
Mass per unit length: 1.6 g / m
Specific gravity: 1.8
Surface oxygen concentration ratio [O / C]: 0.06
Tensile strength: 4600 MPa
Tensile modulus: 220 GPa.

Reference Example 2 Sizing Treatment A sizing agent mother liquor in which a polyfunctional compound was dissolved or dispersed in water so as to be 2% by weight was prepared, a sizing agent was applied to the carbon fiber by a dipping method, and drying was performed at 230 ° C. The adhesion amount was 1.0% by weight.

Example 1
The extruder cylinder temperature of a long fiber reinforced resin pellet manufacturing apparatus, in which a molten resin coating die port is installed at the discharge tip of a single screw extruder, is set to 220 ° C., and polypropylene resin (Prime Polymer Co., Ltd. Prime) Polypro J105G resin) and maleic acid-modified polypropylene resin (Admer QE840 manufactured by Mitsui Chemicals, Inc.) are pellet-blended at a ratio of 85:15 and supplied from the main hopper. (C) Trioctyl phosphate (Wako Jun) as flame retardant (Reagent manufactured by Yakuhin Kogyo Co., Ltd.) was also supplied from the main hopper, melted at a screw rotation speed of 200 rpm, and (a-1) glycerol triglycidyl ether was used as a polyfunctional compound from the upstream side of the extruder as Reference Example 1. And the continuous carbon fiber bundle obtained from Reference Example 2 is a die port (direct And supplies to 3 mm), after cooling the strands coated with resin, and cut into pellet length 10mm length was pelletized molding material by a pelletizer. The supply was adjusted so that the carbon fiber content was 20% by weight.

  Next, the pellet-shaped molding material obtained in the extrusion process was injected using a SE75DUZ-C250 injection molding machine manufactured by Sumitomo Heavy Industries, Ltd., injection time: 10 seconds, holding pressure: molding lower limit pressure + 10 MPa, holding pressure time: A test piece for characteristic evaluation (molded product) was molded at 10 seconds, a cylinder temperature: 230 ° C., and a mold temperature: 60 ° C. The obtained test piece was subjected to a characteristic evaluation test after being left in a constant temperature and humidity chamber adjusted to a temperature of 23 ° C. and 50% RH for 24 hours. Next, the obtained test piece for characteristic evaluation (molded product) was evaluated according to the above-described injection molded product evaluation method. The evaluation results are collectively shown in Table 1.

Example 2
(A) Polypropylene resin blended with propylene homopolymer (Prime Polypro J105G resin manufactured by Prime Polymer Co., Ltd.) and maleic acid-modified polypropylene resin (Admer QE840 manufactured by Mitsui Chemicals Co., Ltd.) in a ratio of 85:15 A pellet was prepared in the same manner as in Example 1 except that 75% by weight and 5% by weight of (C) flame retardant (c-1) trioctyl phosphate (a reagent manufactured by Wako Pure Chemical Industries, Ltd.) were used, Molding evaluation was performed. The characteristic evaluation results are collectively shown in Table 1.

Example 3
(A) Polypropylene resin blended with propylene homopolymer (Prime Polypro J105G resin manufactured by Prime Polymer Co., Ltd.) and maleic acid-modified polypropylene resin (Admer QE840 manufactured by Mitsui Chemicals Co., Ltd.) in a ratio of 85:15 70% by weight and (C) flame retardant (c-2) zinc borate (reagent zinc borate 3.5 hydrate manufactured by Wako Pure Chemical Industries, Ltd.) 10% by weight, except that the same as in Example 1 A pellet was prepared and evaluated for molding. The characteristic evaluation results are collectively shown in Table 1.

Example 4
(A) Polypropylene resin blended with propylene homopolymer (Prime Polypro J105G resin manufactured by Prime Polymer Co., Ltd.) and maleic acid-modified polypropylene resin (Admer QE840 manufactured by Mitsui Chemicals Co., Ltd.) in a ratio of 85:15 75% by weight, and (C) flame retardant (c-2) zinc borate (reagent zinc borate 3.5 hydrate, manufactured by Wako Pure Chemical Industries, Ltd.) 5% by weight A pellet was prepared and evaluated for molding. The characteristic evaluation results are collectively shown in Table 1.

Example 5
(A) Polypropylene resin blended with propylene homopolymer (Prime Polypro J105G resin manufactured by Prime Polymer Co., Ltd.) and maleic acid-modified polypropylene resin (Admer QE840 manufactured by Mitsui Chemicals Co., Ltd.) in a ratio of 85:15 A pellet was prepared in the same manner as in Example 1 except that 70% by weight and 10% by weight of (C) flame retardant (c-3) aluminum hydroxide (Hijilite H-32I manufactured by Showa Denko KK) were used. Then, molding evaluation was performed. The characteristic evaluation results are collectively shown in Table 1.

Example 6
(A) Polypropylene resin blended with propylene homopolymer (Prime Polypro J105G resin manufactured by Prime Polymer Co., Ltd.) and maleic acid-modified polypropylene resin (Admer QE840 manufactured by Mitsui Chemicals Co., Ltd.) in a ratio of 85:15 70% by weight and (C) flame retardant (c-4) hydrotalcite (hydrotalcite compound DHT-4A manufactured by Kyowa Chemical Industry Co., Ltd.) 10% by weight, except that it was used in the same manner as in Example 1. Pellets were prepared and evaluated for molding. The characteristic evaluation results are collectively shown in Table 1.

Example 7
(A) A polypropylene resin blended with a propylene homopolymer (Prime Polypro J105G resin manufactured by Prime Polymer Co., Ltd.) and a maleic acid-modified polypropylene resin (Admer QE840 manufactured by Mitsui Chemicals, Inc.) in a ratio of 85:15. A pellet was prepared in the same manner as in Example 1 except that 70% by weight, (C) flame retardant (c-5) phosphorus, and nitrogen compound (ADEKA STAB FP-2200 manufactured by ADEKA Corporation) 10% by weight were used. Then, molding evaluation was performed. The characteristic evaluation results are collectively shown in Table 1.

Example 8
In addition to the blend composition of Example 1, (D) A pellet was prepared in the same manner except that 20 parts by weight of an ethylene-α-olefin copolymer (Sumitomo Chemical Co., Ltd. CX5505) was added as an elastomer, and molding evaluation was performed. . The characteristic evaluation results are collectively shown in Table 1.

Comparative Example 1
(A) Polypropylene resin blended with propylene homopolymer (Prime Polypro J105G resin manufactured by Prime Polymer Co., Ltd.) and maleic acid-modified polypropylene resin (Admer QE840 manufactured by Mitsui Chemicals Co., Ltd.) in a ratio of 85:15 A pellet was prepared in the same manner as in Example 1 except that 80% by mass and (C) the flame retardant was not added, and molding evaluation was performed. The ratio of the carbon fiber in the obtained molded product is 20% by mass, and (A) the propylene resin is 80% by mass. The characteristic evaluation results are collectively shown in Table 2.

Comparative Example 2
Nippon Steel Works Co., Ltd. TEX-30α type twin screw extruder (screw diameter 30mm, L / D = 32), (A) polypropylene resin, propylene homopolymer (Prime Polymer Co., Ltd. Prime Polypro J105G) Resin) and maleic acid-modified polypropylene resin (Admer QE840 manufactured by Mitsui Chemicals Co., Ltd.) in a pellet blend ratio of 85:15, (C) flame retardant (c-1) trioctyl phosphate (Wako Pure) 10% by weight of a reagent manufactured by Yakuhin Kogyo Co., Ltd. is supplied from the main hopper, then from the downstream side hopper, as (b) reinforcing fiber, (a) polyfunctional compound, (a-1) glycerol triglycidyl A continuous carbon fiber bundle obtained from Reference Example 1 was cut into 1/4 inch with a cartridge cutter using ether. Supplies, barrel temperature 220 ° C., sufficient kneading at a rotation speed of 150 rpm, was further degassed downstream of the vacuum vent. The supply was adjusted by a weight feeder so that the content of carbon fiber alone was 20% by mass. The molten resin was discharged from a die port (diameter 5 mm), and the obtained strand was cooled and then cut with a cutter to produce a pellet-shaped molding material, and molding evaluation was performed. The characteristic evaluation results are collectively shown in Table 2.

Comparative Example 3
A long fiber pellet molding material having a pellet length of 10 mm was prepared by the same formulation and manufacturing method as in Example 1. A square plate of 100 mm × 150 mm × thickness 3 mm was formed by a hot press machine in which the pellet was set to a hot plate temperature of 220 ° C., and a combustion test was performed. Similarly, a test piece for measuring mechanical properties was produced by press molding, and the mechanical properties were evaluated. The characteristic evaluation results are collectively shown in Table 2.

Comparative Example 4
(A) Polypropylene resin blended with propylene homopolymer (Prime Polypro J105G resin manufactured by Prime Polymer Co., Ltd.) and maleic acid-modified polypropylene resin (Admer QE840 manufactured by Mitsui Chemicals Co., Ltd.) in a ratio of 85:15 70% by weight, (C) flame retardant (c-1) trioctyl phosphate (reagent manufactured by Wako Pure Chemical Industries, Ltd.) 10% by weight, and (b) as an alternative to carbon fiber, glass fiber (Nitto Boseki ( Pellets were prepared in the same manner as in Example 1 except that glass roving RS240PE-535) manufactured by the same company was used, and molding evaluation was performed. The characteristic evaluation results are collectively shown in Table 2.

  The carbon fiber reinforced polypropylene resin molded product of the present invention is excellent in flame retardancy and moldability, and has good interfacial adhesion between the reinforced fiber and polypropylene resin. -It is suitably used for electronic equipment, OA equipment, household electrical appliances or automobile structural parts, internal members and housings.

A, B End L1 of carbon fiber in molded product L1 Linear distance L2 of carbon fiber in molded product Both ends of carbon fiber

Claims (5)

(A) Polypropylene resin 40 to 94.5% by weight, (B) Carbon fiber 5 to 40% by weight, and (C) Flame retardant 0 with the total of (A), (B) and (C) as 100% by weight A carbon fiber reinforced polypropylene resin molded product containing 5 to 20% by weight, wherein (B) the carbon fiber is bent and present in the molded product. When the linear distance between both ends of each (B) carbon fiber in the molded product is L1, the fiber length is L2, and the ratio L2 / L1 is the degree of bending, the weight average of the degree of bending is 1.2 or more. The carbon fiber reinforced polypropylene resin molded product according to claim 1. (B) The carbon fiber reinforced polypropylene resin molded product according to claim 1 or 2, wherein the carbon fiber is sizing treated with a polyfunctional compound. The carbon fiber reinforced propylene according to any one of claims 1 to 3, comprising 0.01 to 30 parts by weight of (D) elastomer with respect to 100 parts by weight of the total of (A), (B) and (C). Resin molded products. (A) A resin pellet containing a polypropylene resin, (B) carbon fiber, and (C) a flame retardant, and (B) injection molding a long fiber pellet in which the fiber length of the carbon fiber is substantially equal to the pellet length. The carbon fiber reinforced polypropylene resin molded product according to any one of claims 1 to 4, which is obtained by:

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