JP4743593B2 - Manufacturing method of long fiber reinforced polypropylene resin molding material - Google Patents

Description

  The present invention relates to a novel method for producing a long fiber reinforced polypropylene resin molding material using carbon fibers as reinforcing fibers.

  Conventionally, as a long fiber reinforced thermoplastic resin molding material, a material in which a reinforced fiber is impregnated with a thermoplastic resin as a matrix resin and made into a pellet is known. Moreover, as a method for producing a long fiber reinforced thermoplastic resin composition, a resin obtained by plasticizing and melting a matrix resin raw material with an extruder was filled in an impregnation die, and the resin was drawn from a wound body or the like into the impregnation die. A method is known in which a reinforcing fiber, that is, a fiber bundle which is an aggregate of filaments, is passed, and a continuous reinforcing material obtained by shaping the obtained resin-impregnated fiber bundle with a nozzle is cut with a pelletizer to form pellets.

  As a thermoplastic resin of the long fiber reinforced thermoplastic resin molding material. Polypropylene resin is widely used because it is relatively inexpensive, lightweight, and easy to mold. On the other hand, carbon fibers are suitably employed as reinforcing fibers because they are lightweight and have mechanical properties such as excellent strength and elastic modulus.

  The long-fiber polypropylene resin molding material using carbon fibers generally has poor wettability and adhesion between the polyprolene resin and the carbon fibers, so that the mechanical strength of the molded product tends to decrease. For this reason, in order to improve the wettability and adhesiveness of a polyprolene resin and carbon fiber, it is necessary to process the surface of carbon fiber with a suitable processing agent, and selection of the processing agent is important.

  As the carbon fiber treating agent when the matrix resin is a polypropylene resin, for example, Patent Document 1 preferably uses a treating agent in which a functional group such as a carboxyl group or a phenolic hydroxyl group is introduced on the surface of the carbon fiber. It is disclosed. As a specific treatment agent, a liquid modified polyolefin such as polypropylene, which is the same as the matrix resin, is disclosed. The liquid modified polyolefin includes a toluene solution of chlorine-modified polypropylene, a toluene solution of maleic anhydride-modified polypropylene, and a terminal-modified hydrogen. Additive polybutadiene and the like are described.

  Patent Document 2 discloses that an epoxy resin and a specific silane compound are used as a carbon fiber treating agent when the matrix resin is a polyamide resin, and these are simultaneously applied to the carbon fiber. . In this case, although it is a silane compound that normally has no coupling action on carbon fiber, the use of a specific silane compound allows the carbon in the polyamide resin to interact with the epoxy resin and the polyamide resin. It is described that the dispersibility and fluidity of the fibers are improved.

JP 2003-277525 A JP-A-60-53544

  In the case of the above-mentioned patent document 1, since a polypropylene resin of the same type as the matrix resin polypropylene resin is used as the carbon fiber treating agent, it is expected that the mechanical strength is improved, but the polypropylene resin as a film forming agent is expected. (Generally, it is applied in the form of emulsion) has poor tackiness, so it has poor convergence to the fiber bundle, and the fiber bundle is easy to open even with a small amount of bending in the process, causing fluffing and disconnection. Since it is easy, it has a problem that workability is inferior. This is because carbon fiber has an excellent elastic modulus, but because it is rigid, it does not compensate for the disadvantage inherent to carbon fiber that the filament is very easy to bend against bending and fluff is likely to occur. It is due to that.

  Patent Document 2 discloses that an epoxy resin and a specific silane compound are used as a carbon fiber treating agent when a polyamide resin is used as a matrix resin. In this case, by using an epoxy resin as the treatment agent, the carbon fiber bundle becomes flexible, and the workability is good because it has appropriate convergence and flexibility.

  This is because the carbon fiber bundle treated with an epoxy resin as a film forming agent is imparted with appropriate convergence and flexibility due to the good tackiness of the epoxy resin.

  If the matrix resin is a polypropylene resin, the adhesion between the epoxy resin and the polypropylene resin, which is the treatment agent, is poor, so the key to the tensile strength and bending strength of the molded product obtained from the molding material is important. Due to problems such as insufficient mechanical strength and poor adhesion, long fiber pellets tend to break vertically along the longitudinal direction of the fiber in the long fiber molding material cutting process (pelletizing process) Has the problem of becoming.

  Therefore, in a long-fiber reinforced thermoplastic resin molding material that uses carbon fiber as the reinforcing fiber and polypropylene resin as the matrix resin, the surface treatment agent includes carbon fiber handling workability and polypropylene resin adhesion. One function is required.

  The object of the present invention is to use a carbon fiber as a reinforcing fiber and a long fiber reinforced thermoplastic resin molding material using a polypropylene resin as a matrix resin. By separating and treating an appropriate treatment agent in an appropriate process, it becomes possible to separate and impart necessary functions to the treatment agent, and the workability in the process is good, and the obtained molding An object of the present invention is to provide a carbon fiber reinforced polypropylene molding material and a manufacturing method thereof, which are excellent in mechanical strength such as tensile strength and bending strength, and further have good adhesiveness, so that the molding material is not cracked.

  As a result of diligent research, the inventor of the present invention, when producing a long fiber resin molding material using a polypropylene resin, usually uses a polypropylene resin as a treatment agent. The primary treatment agent and aminosilane compound are used as the secondary treatment agent, and these treatment agents are applied sequentially, unlike Patent Document 2, and further contain a specific amount of acid-modified polypropylene resin as a matrix resin. The present inventors have found that the object of the present invention can be achieved by using a polypropylene resin to achieve the present invention.

Thus, the present invention is characterized by the following gist.
(1) A carbon fiber bundle is dried after adhering a primary treatment agent containing an epoxy resin to carbon fibers, and then the carbon fiber bundle is dried by adhering a secondary treatment agent containing an aminosilane compound. A method for producing a long fiber reinforced polypropylene resin molding material, characterized by impregnating a polypropylene resin containing 1% by mass or more of an acid-modified polypropylene resin and drawing it.
(2) The total amount of the primary treatment agent and the secondary treatment agent is 0.4 to 8 parts by mass in solid content per 100 parts by mass of the carbon fiber bundle to which the primary treatment agent and the secondary treatment agent are adhered. And the manufacturing method of the long fiber reinforced polypropylene resin molding material as described in said (1) whose aminosilane compound is 0.2-4 mass parts per 100 mass parts of said carbon fiber bundles.
(3) The method for producing a long fiber reinforced polypropylene resin molding material according to (1) or (2) above, wherein an aminosilane compound is present on the surface of the carbon fiber bundle after the secondary treatment agent is attached and dried.
(4) The polypropylene resin has a MFR of 20 to 400 g / 10 min (230 ° C. 2.16 Kg), is composed of a polypropylene resin containing 1% by mass or more of acid-modified polypropylene resin, and has a carbon fiber content of 10 The manufacturing method of the long fiber reinforced polypropylene resin molding material as described in said (1), (2) or (3) which is -60 mass%.
(5) A carbon fiber bundle for a long fiber reinforced polypropylene resin molding material in which a polypropylene resin containing 1% by mass or more of an acid-modified polypropylene resin is a matrix resin, and a primary treatment agent containing an epoxy resin is attached to the carbon fiber A carbon fiber bundle, wherein the carbon fiber bundle is heated and dried after being made to adhere, and then a secondary treatment agent containing an aminosilane compound is adhered thereto and dried by heating.

  According to the present invention, when producing a long fiber molding material using carbon fiber as the reinforcing fiber and using polypropylene resin as the matrix resin, it is possible to use a carbon fiber bundle having suitable convergence and flexibility. There is provided a method for producing a long fiber reinforced polypropylene molding material which is possible and has no cracks as a molding material, and the resulting molded article is excellent in mechanical strength such as tensile strength and bending strength.

  Although it is not necessarily clear why the present invention has such excellent effects as described above, it is estimated as follows. In other words, an epoxy resin is attached to the carbon fiber as a treatment agent in order to improve the handleability of the carbon fiber and the interfacial adhesion between the carbon fiber surface and the treatment agent, and the adhesion between the matrix resin and the treatment agent is good. In order to improve the mechanical strength of the molded product, a large amount of aminosilane compound is adhered as a treating agent. When a large amount of the above-mentioned silane coupling agent is adhered to a wound body once and introduced into the resin impregnation step, the carbon fiber becomes stiff and extremely difficult to handle. It is considered that the above-described effect is exhibited by applying the aminosilane compound before the impregnation step.

  As the carbon fiber used for the long fiber reinforced polypropylene resin molding material in the present invention, any carbonaceous fiber such as polyacrylonitrile-based or pitch-based can be used, and among them, polyacrylonitrile-based carbon fiber is preferable. The average fiber diameter of the carbon fibers is preferably 4 to 10 μm, and particularly preferably 6 to 8 μm. When the fiber diameter is less than 4 μm, the production cost of the fiber is increased, which is not economically preferable. In addition, in order to obtain a specific fiber content, a large number of fibers are inevitably required, and the resin into the fiber. The impregnation property of is reduced, which is not preferable. On the other hand, when the fiber diameter exceeds 10 μm, the mechanical strength of the obtained molded product is lowered, which is not preferable.

  The carbon fiber used in the present invention is used in the form of a fiber bundle of single fibers having the above specific fiber diameter. Usually, a fiber bundle of preferably 3,000 to 50,000, particularly preferably 10,000 to 25,000 single fibers is produced, and preferably 1 to 8 bundles of this fiber bundle are drawn out. Those are preferred. When the number of the above-mentioned fiber bundles exceeds 8, not only the workability is inferior, but also a space for installing a wound body corresponding thereto is required, which is not preferable.

  When producing a carbon fiber bundle from the carbon fiber, in the present invention, the carbon fiber is first surface-treated with a primary treatment agent. An epoxy resin is used as the primary treatment agent. As the epoxy resin, a bisphenol A type epoxy resin, a urethane-modified epoxy resin, a novolac type epoxy resin, or a mixed type epoxy resin thereof can be used. Of these, bisphenol A type epoxy resins are preferred. These epoxy resins are preferably used in the form of a solvent solution, an aqueous solution, or an aqueous emulsion, but it is preferable to use an aqueous solution containing no solvent or an aqueous emulsion solution from the viewpoint of the working environment. Further, the primary treatment agent of the present invention is not particularly limited as long as the above-described epoxy resin is contained, and may be used in combination with other resin treatment agents such as polyester resin, and silane. A coupling agent such as an aminosilane compound can also be used in combination.

  The amount of the primary treatment agent attached to the carbon fiber is 0.2 to 4% by mass in solid content with respect to the carbon fiber containing the primary treatment agent, and more particularly 0.5 to 1.5% by mass. preferable. When the adhesion amount is less than 0.2% by mass, the convergence property of the carbon fiber bundle is inferior, and when pulling out the fiber from the wound body or pulling out the impregnation die, a single piece, fluffing, etc. are caused, and disconnection is caused. In addition to clogging the nozzle of the impregnation die, the mechanical strength of the molded product is inferior. Further, if the adhesion amount exceeds 4% by mass, the fiber bundle does not open in the impregnation die, impregnation failure occurs, and the carbon fiber remains in the molded product without being impregnated with polypropylene resin. Variations in mechanical strength and poor surface appearance are undesirable.

  The carbon fiber to which the primary treatment agent is attached is once dried. There is no restriction | limiting in particular as a drying method here, Well-known methods, such as infrared heating, heater heating, and hot air heating, can be selected suitably. Thus, an epoxy resin film as a primary treatment agent is formed on the surface of the carbon fiber. The carbon fiber bundle having the primary treatment agent film on the surface may be treated with the aminosilane compound as the secondary treatment agent as it is, but for convenience of handling, it is wound around an appropriate wound body and the secondary treatment agent. Can be stored before processing.

  In the case of treating carbon fiber with a secondary treatment agent, in the present invention, it is important to further apply a secondary treatment agent to the carbon fiber that has been adhered and dried with the primary treatment agent, and to use an aminosilane compound as the secondary treatment agent. is there. It can be obtained by improving the handleability of carbon fiber with the primary treatment agent attached, suppressing the generation of fluff and breakage due to bending of the filament by bending in the handling process, and attaching the aminosilane compound as the secondary treatment agent. Improve the mechanical strength of the molded product. By attaching a large amount of aminosilane compound as a secondary treatment agent, the fiber becomes stiff, but by attaching a secondary treatment agent just before impregnating polypropylene into carbon fiber, it suppresses filament breakage and breakage due to bending etc. It is.

  Examples of the aminosilane compound include γ-aminopropyltriethoxysilane, NB- (aminoethyl) -γ-aminopropyltrimethoxysilane, NB- (aminoethyl) -N′-β- (aminoethyl) -γ-aminopropyl. Trimethoxysilane, γ-anilinopropyltrimethoxysilane and the like are used, and γ-aminopropyltriethoxysilane is preferably used. The secondary treatment is usually used in the form of an aqueous solution dissolved with water. The secondary treatment is usually performed by attaching a solution or dispersion containing an aminosilane compound while pulling out the carbon fiber bundle wound up on the wound body.

  The method of adhering the secondary treatment agent is not particularly limited, and may be a known treatment method such as roll coater, curtain coater type application, spray type application, dipping type application or the like. The secondary treatment is preferably performed during the production process of the long fiber reinforced polypropylene resin, and is preferably attached immediately before the carbon fiber is impregnated with the polypropylene resin. In this case, the roll coater coating method is preferable from the viewpoint that the amount of adhesion is easy to control and that the bending that causes damage to the carbon fiber bundle is relatively small. Thereafter, the carbon fiber to which the secondary treatment agent is attached is dried, but there is no particular limitation. For example, by passing through an oven heated to 200 to 300 ° C., the long fiber reinforced polypropylene resin is being manufactured. Can be dried well. As the heating method, a known method such as infrared heating, heater heating, hot air heating or the like can be used. In this way, a film of an aminosilane compound as a secondary treatment agent is formed on the surface of the carbon fiber bundle.

  The amount of the treatment agent attached to the carbon fiber to which the primary treatment agent and the secondary treatment agent are adhered is obtained as described above per 100 parts by mass of the carbon fiber to which the primary treatment agent and the secondary treatment agent are adhered. The total amount of the agent and the secondary treatment agent is preferably 0.4 to 8 parts by mass, particularly 0.8 to 6 parts by mass in terms of solid content. When the adhesion amount of the treatment agent is smaller than 0.4 parts by mass, the convergence is likely to be insufficient, and workability is deteriorated, and sufficient adhesiveness cannot be imparted, so that the strength in the molded product cannot be obtained. . On the other hand, when the amount is larger than 8 parts by mass, the bundling property becomes too strong, the impregnation property in the matrix resin impregnation step into the carbon fiber is likely to be lowered, and the workability is deteriorated because the fiber is easily rigid. Therefore, it is inconvenient. Of the above-mentioned treatment agents, the amount of the aminosilane compound attached is preferably 0.2 to 4 parts by mass in terms of solid content per 100 parts by mass of the carbon fiber to which the primary treatment agent and the secondary treatment agent are adhered. Is preferably 0.5 to 2 parts by mass.

  In the present invention, the adhesion amount in the primary treatment and the secondary treatment can be determined as follows. First, after the primary treatment agent was attached and dried, the weight W1 of the carbon fiber to which the primary treatment agent was attached as a solid content and the carbon fiber was heated (thermally decomposed) at 450 ° C. for 30 minutes in a nitrogen atmosphere. Thereafter, the adhesion amount P1 of the primary treatment agent was calculated from (W1-W2) × 100 / W1 based on the weight W2 after cooling to room temperature in a nitrogen atmosphere. (Unit is part by mass with respect to 100 parts by mass of carbon fiber to which the treatment agent is attached as a solid content). Moreover, the mass part C1 of the carbon fiber at that time was calculated by 100-P1.

  Then, after the secondary treatment agent is further adhered and dried, the weight W3 of the carbon fiber to which the treatment agent is adhered as a solid content, and the weight W4 after cooling measured by the thermal decomposition method as described above, From (W3-W4) × 100 / W3, the mass part C2 of the carbon fiber at that time was calculated from the total adhesion amount P2 of the primary treatment agent and the secondary treatment agent and 100-P2. The adhesion amount of the secondary treatment agent was calculated by P2- (P1 × C2 / C1).

  In addition, when the aminosilane compound is contained in the primary treatment agent, the aminosilane compound is also included in the adhesion amount of the aminosilane compound.

  The polypropylene resin that is a matrix resin used in the present invention is a polypropylene resin containing an acid-modified polypropylene resin. As the polypropylene resin, polypropylene copolymers such as polypropylene homopolymer, ethylene-propylene random copolymer, ethylene-propylene block copolymer, ethylene-α-propylene copolymer, propylene-α-propylene copolymer, etc. Can be used.

  As the acid-modified polypropylene resin, a homopolymer or copolymer of polypropylene modified with an unsaturated carboxylic acid or a derivative thereof is also preferable. Preferred examples thereof include those obtained by graft polymerization of an unsaturated carboxylic acid or a derivative thereof on polypropylene, a random or block copolymerization of one or more selected from propylene and an unsaturated carboxylic acid or a derivative thereof, or These polymers may further include those obtained by graft polymerization of unsaturated carboxylic acids or their derivatives.

  Examples of the unsaturated carboxylic acid used for the carboxylic acid modification include maleic acid, fumaric acid, itaconic acid, acrylic acid, and methacrylic acid. Examples of unsaturated carboxylic acid derivatives include anhydrides, esters, amides, imides, and metal salts of these acids. Specific examples thereof include maleic anhydride, itaconic anhydride, methyl acrylate, ethyl acrylate, butyl acrylate, glycidyl acrylate, methyl methacrylate, ethyl methacrylate, glycidyl methacrylate, monoethyl maleate, maleic acid Examples include diethyl ester, fumaric acid monomethyl ester, fumaric acid dimethyl ester acrylamide, methacrylamide, maleic acid monoamide, maleic acid diamide, fumaric acid monoamide, maleimide, N-butylmaleimide, and sodium methacrylate.

  Of the above unsaturated carboxylic acids and derivatives thereof, preferred are glycidyl esters of acrylic acid or methacrylic acid, or maleic anhydride. Preferred acid-modified polypropylene resins modified by these are those modified by graft polymerization of maleic anhydride to a polyolefin resin having ethylene and / or propylene as the main resin structural unit, and mainly composed of ethylene and / or propylene. Examples thereof include those obtained by acid-modifying polypropylene and (meth) acrylic acid glycidyl ester or maleic anhydride.

  In the present invention, the content of the acid-modified polypropylene resin in the polypropylene resin needs to be 1% by mass or more, and when this content is less than 1% by mass, the adhesion to the carbon fiber surface is poor. Therefore, it is inappropriate.

  The polypropylene resin containing the acid-modified polypropylene resin used in the present invention has an MFR (melt flow rate, 230 ° C., 2.16 kg)) value of preferably 20 to 400 g / 10 min, particularly preferably 30 to 300 g / 10 minutes is preferred. When the MFR value is less than 20 g / 10 min, it becomes difficult for the polypropylene resin to impregnate into the carbon fiber bundle in the impregnation die, and the mechanical strength of the resulting molded product varies, and the surface appearance deteriorates. It is not preferable. On the other hand, when the MFR value exceeds 400 g / 10 min, the impregnation property is improved, but the mechanical strength of the resin itself is lowered, and the mechanical strength of the resulting molded product is inferior.

  In the present invention, a long fiber reinforced polypropylene resin molding material is produced by impregnating a carbon fiber bundle subjected to the above surface treatment with a molten polypropylene resin. That is, the carbon fiber bundle is drawn out of the impregnation die to which the extruder is attached, and is impregnated with the molten polypropylene resin in the meantime. Several bars are installed in the impregnation die, and the carbon fiber bundle is opened as it passes through it.

  On the other hand, in order to further improve the impregnation property / productivity and the dispersibility of the carbon fiber in the finally obtained molded article, a polypropylene resin which is plasticized and melted at 240 to 300 ° C. is preferably used as the impregnation die. The carbon fiber bundle which has been fed and spread is impregnated into the carbon fiber bundle, and the carbon fiber bundle impregnated with the polypropylene resin is cooled by excess polypropylene resin being squeezed by a die or the like at the exit of the impregnation die. The plasticizing temperature of the polypropylene resin is preferably adjusted according to the MFR value corresponding to the carbon fiber content and the degree of impregnation.

  The carbon content in the long fiber reinforced polypropylene resin molding material thus obtained is preferably 10 to 60% by mass, and more preferably 25 to 50% by mass. When the carbon content exceeds 60% by mass, the amount of carbon fibers increases and impregnation with polypropylene resin tends to be insufficient. On the other hand, if it is less than 10% by mass, the reinforcing effect of the carbon fiber is not sufficient, which is not preferable.

  Next, the carbon fiber bundle impregnated with the long fiber reinforced polypropylene resin is preferably cut into a length of 3 to 20 mm, particularly preferably 5 to 15 mm by a cutting machine. When the cutting length is less than 3 mm, the obtained long fiber reinforced polypropylene resin molding material is easily cracked in the vertical direction, causing problems such as fluffing. On the other hand, if the cutting length exceeds 20 mm, hopper clogging occurs in the molding machine, resulting in insufficient supply of materials, dispersibility of carbon fibers during molding, and variations in mechanical strength in the resulting molded product. In addition, appearance defects due to non-dispersion in the surface appearance of the molded product are likely to occur.

The produced long fiber reinforced polypropylene resin molding material is used for molding alone or mixed with other resins. In this case, the resin used for mixing is not necessarily the same as the polypropylene resin contained in the long fiber reinforced polypropylene resin molding material, and a thermoplastic resin is appropriately used to impart the necessary properties to the molded product. Can be mixed.

  Although the molding method in the manufacturing method of the molded article using the long fiber reinforced polypropylene resin molding material of the present invention is not particularly limited, injection molding is preferably used. In the present invention, it is preferable that the carbon fibers in the molded product are dispersed with a weight average fiber length of preferably 2 mm or more. In order to manufacture such a molded article, it is preferable to use a molding machine equipped with a screw having a deep groove and a nozzle having a large diameter.

  The long fiber reinforced polypropylene resin molding material of the present invention can contain an appropriate additive in order to impart desired characteristics to the molded product within a range that does not significantly impair the object of the present invention. For example, stabilizers such as antioxidants and ultraviolet absorbers, antistatic agents, colorants such as dyes and pigments, lubricants, plasticizers, glass fibers, glass flakes, glass powders, glass beads, mica, alumina and carbon powders An appropriate amount of an inorganic material such as the above may be blended. Also, a compound selected from a lubricant such as a metal salt of a fatty acid effective for improving the fluidity of the molding material during molding and homogenizing the reinforcing fiber, for example, a salt of a fatty acid having 28 to 30 carbon atoms and a metal such as lithium. Can be blended in an appropriate amount.

  The present invention will be described more specifically with reference to the following examples. However, the present invention should not be construed as being limited to such examples.

Examples 1-7 and Comparative Examples 1-4
In the following Examples and Comparative Examples, each material used for production of the long fiber reinforced polypropylene resin molding material is as follows.
a. Carbon fiber / PAN-based carbon fiber, average diameter of filament: 7 μm, number of bundling: 12K (1200), TEX count 800g / km × 2 / nozzle (2400 / nozzle)
b. Primary treatment agent (primary treatment agent for carbon fiber bundles)
・ Uses carbon fibers to which the following treatment agents are attached.
Other than Comparative Example 4: 1.0 part by weight of bisphenol A type epoxy resin in solid content Comparative Example 4: 1.0 part by weight of maleic anhydride-modified polypropylene resin in solid content (100 parts by weight of carbon fiber bundle containing primary treatment agent) Amount of adhesion against
c. Secondary treatment agent (secondary treatment agent for carbon fiber bundle with primary treatment agent attached)
Aminosilane (Compound name: γ-aminopropyltriethoxysilane)
d. Polypropylene resin (matrix resin)
Polypropylene homopolymer:
MFR (230 ° C., 2.16 kg) = 30, 120, 250, 500 (g / 10 min)
e. Acid-modified polypropylene (addition to matrix resin)
Maleic acid-modified polypropylene (maleic acid content 1% by mass, MFR (190 ° C., 325 g) = 10 (g / 10 min)

Using the above-mentioned material, a long fiber reinforced polypropylene resin material was produced by the following method, and injection molded, and the tensile strength and bending strength of the molded product were evaluated. The results are shown in Table 1.

1. Manufacture of long fiber reinforced polypropylene resin molding materials:
While opening the carbon fiber bundle with an impregnation die and pulling it, plasticizing it with an extruder, melting it and infiltrating the melt of polypropylene resin sent to the impregnation die, and then drawing it as a strand through the shaping die After cooling, it was cut into a length of 8 mm with a cutting machine. The plasticization and melting temperature was 280 ° C.

2. Manufacture of molded products:
Using the long fiber reinforced polypropylene resin molding material obtained above, a cylinder temperature of 250 ° C. and an injection speed of 12.7 mm / in accordance with JIS-K8921-2 using a long fiber injection molding machine and a multipurpose test piece mold. A multi-purpose test piece (JIS K7139) for physical property testing was produced by injection molding under the conditions of sec.

3. Evaluation method a. Evaluation of carbon fiber workability (fluff, disconnection):
When a continuous fiber reinforced polypropylene resin molding material is produced using a carbon fiber bundle that has been subjected to a primary treatment and crushed as a rotating body, the carbon fiber bundle is first generated in the process during the process. The amount of accumulated fluff per hour was converted and evaluated per fiber bundle, and evaluation was performed based on the presence or absence of disconnection at the nozzle portion due to the occurrence of fluff. The evaluation of the results was judged as follows.
○: The amount of fluff per fiber bundle is less than 1 mg / hour and there is no sign or occurrence of breakage. ×: The amount of fluff per fiber bundle is 1 mg / hour or more, sign of breakage or 1 There are more than one disconnection.
b. Evaluation of pellet cracking:
50 g of pellets cut to 8 mm were weighed and spread on a beautiful white tray so that the samples did not overlap, and a 36 W white fluorescent lamp was brought close to the sample within 50 cm and observed visually. The pellets were peeled off in the longitudinal direction and the opposite side could be seen, and those that were completely separated were regarded as “cracks”, and the quality was determined by classifying them according to the number. ○ is good and × is bad.
○: Less than 5 cracks / 50g
X: The number of cracks is 5 or more and less than 10/50 g
c. Evaluation of molded product:
The molded product obtained above was used, and the tensile strength was evaluated according to JIS-K-7161 and the bending strength was evaluated according to JIS-K-7171.
d. Adhesion amount of treatment agent solid content in fiber Adhesion amounts of the primary treatment agent and the secondary treatment agent adhered to the carbon fiber were measured by a thermal decomposition method.

  First, after the primary treatment agent is attached and dried, the weight W1 of the carbon fiber to which the primary treatment agent is attached as a solid content and after heating (pyrolysis) the carbon fiber in a nitrogen atmosphere at 450 ° C. for 30 minutes From the weight W2 after cooling to room temperature in a nitrogen atmosphere, the adhesion amount P1 of the primary treatment agent was calculated from (W1-W2) × 100 / W1. (Unit is part by mass with respect to 100 parts by mass of carbon fiber to which the treatment agent is attached as a solid content). Moreover, the mass part C1 of the carbon fiber at that time was calculated by 100-P1.

  Then, after the secondary treatment agent is further adhered and dried, the weight W3 of the carbon fiber to which the treatment agent is adhered as a solid content, and the weight W4 after cooling measured by the thermal decomposition method as described above, The mass part C2 of the carbon fiber at that time was calculated from (W3-W4) × 100 / W3 by the total adhesion amount P2 of the primary treatment agent and the secondary treatment agent and 100-P2. The adhesion amount of the secondary treatment agent was calculated by P2- (P1 × C2 / C1).

  From the results in Table 1, “Act 1” to “Act 7” in which an appropriate amount of a secondary treatment agent is attached and an appropriate amount of maleic acid-modified PP is added to the matrix resin are excellent in tensile strength and bending strength, Evaluation is also good. Among them, “Act 1”, “Act 3” and “Act 5” with 0.7% by weight of the solid content of the secondary treatment agent and 5.0% by weight of maleic acid-modified polypropylene resin are excellent in strength. I understand that.

  “Real 1”, “Real 3”, “Real 5”, and “Real 7” have different MFR of polypropylene resin, but “Real 1” with MFR 120 and “Real 3” with MFR 30 It can be seen that “real 5” with an MFR of 250 has good strength, and “real 7” with an MFR of 500 has slightly inferior strength.

  On the other hand, “Ratio 1” without adhesion of the secondary treatment agent, “Ratio 2” without addition of maleic acid-modified polypropylene in the matrix resin even when an appropriate amount of secondary treatment agent adheres, and maleic acid modification in the matrix resin It can be seen that “Ratio 3” with a small amount of polypropylene of 0.5% by weight is inferior in both strength and crack evaluation. Even if the amount of the maleic acid-modified polypropylene in the matrix resin is an appropriate amount, the amount of the secondary treatment agent is slightly excessive, but the strength is slightly inferior to “Act 1” and “Act 4”. I understand that.

In addition, the strength of “Ratio 4” using maleic acid-modified polypropylene resin as the primary treatment agent is almost equivalent to “Real 2”, “Real 4”, “Real 6”, “Real 7”. However, the evaluation result of the fluff workability of the carbon fiber in the manufacturing process is “x”, which indicates that the workability is inferior.
In addition, since the thing other than "Ratio 4" has an appropriate amount of epoxy resin attached to the primary treatment agent, the fuzziness workability evaluation results are all "Good", indicating that the workability is good.

Claims (5)

  A carbon fiber bundle is dried after adhering a primary treatment agent containing an epoxy resin to carbon fibers, and then the carbon fiber bundle is dried by adhering a secondary treatment agent containing an aminosilane compound, and then acid-modified. A method for producing a long fiber reinforced polypropylene resin molding material, wherein the polypropylene resin is impregnated with a polypropylene resin containing 1% by mass or more of the polypropylene resin and drawn.   The total amount of the primary treatment agent and the secondary treatment agent is 0.4 to 8 parts by mass in solid content per 100 parts by mass of the carbon fiber bundle to which the primary treatment agent and the secondary treatment agent are adhered, and the carbon The method for producing a long fiber reinforced polypropylene resin molding material according to claim 1, wherein the aminosilane compound is 0.2 to 4 parts by mass per 100 parts by mass of the fiber bundle.   The method for producing a long fiber reinforced polypropylene resin molding material according to claim 1 or 2, wherein the carbon fiber bundle after the secondary treatment agent is attached and dried is coated with an aminosilane compound.   The polypropylene resin has an MFR of 20 to 400 g / 10 min (230 ° C., 2.16 kg), is composed of a polypropylene resin containing 1% by mass or more of acid-modified polypropylene resin, and has a carbon fiber content of 10 to 60 mass. The method for producing a long fiber reinforced polypropylene resin molding material according to claim 1, 2 or 3. A carbon fiber bundle for a long fiber reinforced polypropylene resin molding material in which a polypropylene resin containing 1% by mass or more of an acid-modified polypropylene resin is a matrix resin, and after a primary treatment agent containing an epoxy resin is attached to the carbon fiber A carbon fiber bundle characterized by being dried and then dried by attaching a secondary treatment agent containing an aminosilane compound.