JP2017186492A - Manufacturing method of foam molded body of carbon fiber reinforced modified polypropylene-based resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To overcome a situation that a polypropylene resin has light weight with specific gravity of 0.90 and is expected to have higher strength by carbon fiber reinforcement and to have weight reduction and recycle property, applications as a drone material, an ocean civil engineering material, a high rise building material, a railway vehicle material, an automobile material and other advanced materials are expected to expand by properties of light weight and high strength, however adoption in large amount is not achieved because carbon fiber is expensive and adhesiveness with nonpolar polypropylene is poor.SOLUTION: A polypropylene resin and a maleic acid compound are modified at high steep by a reaction extrusion method using organic peroxide as a catalyst and mixed with an inexpensive carbon fiber mass produced by a large tow method. Further an epoxy resin-based binder and an organic metal-based catalyst are used for increasing reduced molecular weight and melting viscosity and a thermoplastic composite material of a carbon fiber reinforced modified polypropylene resin is manufactured. Further especially a microcapsule foam body is developed for weight saving and increasing strength.SELECTED DRAWING: None

Description

  The present invention relates to providing a method for producing a foam-molded article of carbon fiber reinforced / modified polypropylene resin that is lightweight, high-strength and recyclable.

Conventionally, polypropylene resin is one of the five general-purpose thermoplastic resins, and has excellent physical properties such as good moldability and light weight, mechanical strength, and rigidity. It is used. In particular, in the plastics field, molded products are widely used in bottles, sheets, containers, daily necessities, automotive interior materials and bumpers, machine parts, electrical / electronic materials, building materials, earthwork, various industrial products, and the like.
Polypropylene resin has been used for higher-grade applications because it has improved properties such as mechanical strength and heat resistance by further mixing glass fiber or carbon fiber into a thermoplastic composite material. Yes. In particular, since glass fibers are inexpensive, composite materials reinforced with this are used in large quantities. On the other hand, carbon fiber has high strength but is too expensive, so its use is limited, and it has been used only in a small amount for special purposes as a composite material with ABS resin.
In recent years, in the industrial fields such as civil engineering / architecture, automobile industry, Shinkansen vehicle industry, aerospace industry, linear motor car, etc. In addition to lightening and energy saving, further improvements in performance such as corrosion resistance, electrical characteristics, heat resistance, heat dissipation, etc. are required.

As disclosed in Patent Document 1 and Patent Document 2 as the previous prior invention, the present inventors adopted a reactive extrusion method for a middle molecular weight body having a carboxyl group at the terminal with a polyester resin, and an epoxy resin binder. (Also called a chain extender) and a catalyst, a reaction extrusion method that uses polyester and reacts with each other to achieve high productivity of high molecular weight in a short time of several minutes or less, using compact and inexpensive equipment Provided. In addition, as disclosed in Patent Document 3, the present inventors used polyethylene terephthalate (abbreviated as PET), 15% and 30% by weight of recovered carbon fiber, 6 mm long, and epoxy resin binder (chain extender) and catalyst. In the presence of, the reaction is carried out by a reactive extrusion method using a twin-screw extruder to obtain a recovered carbon fiber reinforced / modified pet resin, the mechanical strength of which is about 2 to 2.4 times the tensile strength and the flexural modulus. This is a significant improvement from about 4 times to 6.8 times. In addition, in the Patent Document 4, the present inventor has disclosed an inexpensive carbon fiber chop (6 mm length, manufactured by ZOLTEK, USA), bundle of 50,000 pieces of PAN-based rayon of large tow (abbreviated as “LT”): 50K-LT) and carbon fiber reinforced / modified pat resin in the same manner. Mechanical strength of 15% and 30% content is about 3 to 4 times in tensile strength and about 6 times in flexural modulus. It has improved significantly by 10 times.
By these prior inventions, it was demonstrated that the thermoplastic resin and carbon fiber containing a carboxyl group have extremely good adhesion and can greatly improve the mechanical strength. However, the improvement in impact strength was insufficient. The reason for this is that in the conventional extrusion apparatus, the fiber length of the carbon fiber chop (6 mm length) and pet resin heated and pellets produced as a kneaded product was drastically reduced to about 0.3 mm length. On the other hand, it has been pointed out that the pet resin has a specific gravity of 1.35, which is about 40% larger and heavier than the specific gravity of polypropylene of 0.90.

For polypropylene, glass fiber reinforced polypropylene has been used for a long time because of its high affinity with surface-treated glass fibers. However, when glass fiber reinforced polypropylene is formed into pellets, the fiber length is crushed and shortened to about 1/10 (3 mm long chop is 0.3 mm remaining length) with the screw of the extruder. Therefore, the mechanical properties expected originally were not obtained.
The inventors of the present invention developed a high-strength, lightweight carbon fiber reinforced / modified polypropylene resin by modifying polypropylene with an unsaturated organic acid or the like, and filed an application earlier.

Notice No. 3503952 International Publication WO2009 / 004745 A1 JP2015-007212A JP2015-157939A

Corrosion resistance, electrical conductivity, heat resistance, as well as further weight reduction and energy saving by improving mechanical strength of structural materials in advanced industrial fields such as civil engineering / architecture, automobile industry, Shinkansen vehicle industry, linear motor car, etc. There is a demand for further improvement in performance such as heat dissipation. The present invention relates to corrosion resistance of outdoor structures by reducing the strength of synthetic timber lacking strength, light weight materials for high-rise buildings, high strength / corrosion resistant materials for coastal highways, corrosion resistance / high strength materials for marine structures, etc. The purpose is to develop materials, especially automotive applications.
There is a demand for new materials that are lighter and have higher strength due to foaming for use as airframe materials for industrial flying bodies (drones) that are rapidly developing.

Means to try to solve the problem

  The present invention provides a method for producing a lightweight and improved carbon fiber reinforced / modified polypropylene resin foam. In particular, the present invention provides a method for producing a micro cab cell (MC) foam having a higher strength than conventional gas foams. Is

More specifically, the present invention provides the following production method.
In the present invention, (A) 100 parts by weight of a polypropylene resin, (B) 20 parts by weight of a polypropylene powder resin, (C) 0.1 to 3 parts by weight of an organic unsaturated acid compound, (D A composition comprising 0.01) to 0.50 parts by weight of an organic peroxide and (E) 0.01 to 1 part by weight of a spreading agent is reacted at a temperature higher than the melting point of polypropylene by a reactive extrusion method. A modified polypropylene and 5-50 parts by weight of a carbon fiber chop (F) are heated and melted, and an MFR (230 ° C., load 2.16 kg) based on the JIS-K7210 method is 0.5 to 10 g / 10 min. The present invention provides a method for producing a foamed article of carbon fiber reinforced / modified polypropylene resin, characterized in that the material (G) is heated and melted in the presence of a foaming agent (H).

  The second aspect of the present invention is a carbon fiber reinforced / modified polypropylene resin characterized in that the foaming agent (H) contains a microcapsule, a chemical foaming agent or a masterbatch containing the microcapsule, or carbon dioxide. The manufacturing method of a foaming molding is provided.

In the present invention, thirdly, a thickener (I) composed of an epoxy binder and an organometallic catalyst is added to the composite material (G) and melted by heating in the presence of a foaming agent (H). The present invention provides a method for producing a foamed article of carbon fiber reinforced / modified polypropylene resin.

Effect of the invention

  According to the present invention, a composite material comprising a modified polypropylene resin whose adhesion to carbon fiber has been dramatically improved and a large tow type carbon fiber (ZOLTEK chop) whose mass production and cost reduction are progressing. Can be used to mold a foam with high strength and light weight at a high speed. In particular, the MC foam molded article according to the present invention is lightweight, high-strength, and can be recycled, so it is expected that it will be used for industrial vehicles (drone) and a huge market for future automobile applications for the time being. Is done. Excellent physical properties such as corrosion resistance, heat resistance, heat transfer, conductivity, oil resistance, and weather resistance.

Hereinafter, the present invention will be described in detail.
[(A) component polypropylene resin]
The polypropylene resin of the component (A) as a main raw material in the present invention is a polypropylene homopolymer, a polypropylene / ethylene block copolymer, a polypropylene / ethylene random copolymer, a polypropylene / ethylene superrandom copolymer, or a recycled product of a recovered molded product thereof. Circulating products can be used. If a strong carbon fiber reinforced composite is desired, a polypropylene homopolymer is selected. When a carbon fiber reinforced composite material having high impact strength is desired, a polypropylene / ethylene block copolymer is selected. In the present invention, since the molecular weight is lowered by molecular cleavage due to the catalytic action of the organic peroxide of component D, it is preferable to select a grade having a large molecular weight and a small MI as the main raw material. That is, it is preferable that MI (230 degreeC, load 2.16Kg) based on JIS-K7210 method is 0.5-10 g / 10min. A hollow molding grade is preferable, and the blending amount of the main raw material is 100 parts by weight.

[(B) Component Polypropylene Powder Resin]
Component (B) is an auxiliary that uniformly disperses 0.1 to 3 parts by weight of the organic unsaturated acid compound of component (C) and 0.01 to 0.50 parts by weight of organic peroxide of component (D). As a role. Polypropylene homopolymer, polypropylene / ethylene block copolymer, polypropylene / ethylene random copolymer, polypropylene / ethylene super random copolymer, or a recycled product of these recovered molded articles can be used in a powder state. MI is also preferably 0.5 to 10 g / 10 min. The amount of the auxiliary material is 1 to 20 parts by weight.

[Organic unsaturated acid compound of component (C)]
As the component (C), maleic anhydride and derivatives thereof can be used, but maleic anhydride is preferable. Its role is to react when the organic peroxide of component (D) attacks the polypropylene to generate radicals in the molecular chain, and stops by giving a carboxyl group to the polypropylene, thereby modifying the originally nonpolar polypropylene. There is. The amount is 0.1 to 3 parts by weight, preferably 0.2 to 1 part by weight. If the amount is 0.1 parts by weight or less, the modification effect of the polypropylene resin is insufficient. If the amount exceeds 3 parts by weight, unreacted substances remain during reaction extrusion and volatilize to cause damage to the human body.

[Organic peroxide of component (D)]
The component (D) organic peroxide can be used as a resin melt flow modifier, maleating agent, and grafting agent, such as Perhexa Series (HC, C, 22, 25B) from NOF Corporation. Etc.), perbutyl series (C, D, P etc.), park mill series (D etc.) can be used. In addition, a master batch having an efficacy of 40% can be more suitably used for storage safety measures for organic peroxides. Commercially available dicumyl diperoxide (manufactured by Aldrich) can be suitably used. The amount is 0.01 to 0.50 parts by weight. If the amount is 0.01 parts by weight or less, the modification effect of the polypropylene resin is insufficient. If it is 0.50 part by weight or more, the lowering of the molecular weight of the polypropylene resin proceeds excessively.

[(E) Component spreading agent]
The component (E) has a role of 0.1 to 3 parts by weight of a fine powder of the organic unsaturated acid compound (C) and a fine powder of the organic peroxide 0.01 to 0 as the component (D). .50 parts by weight have a role of uniformly adhering to the surface of the component (B) polypropylene powder resin. Liquid paraffin is preferred. Paraffin oil and petroleum wax can also be used. A compounding quantity is 0.01-1 weight part.

[Carbon fiber of component (F)]
It is preferable to use a high-strength industrial product as the (F) component carbon fiber in the present invention. As a top priority candidate, an inexpensive carbon fiber chop that can be mass-produced by high-speed firing of large tow (Large Tow: 50,000 filaments / bundle) manufactured by ZOLTEK, USA (LT-rayon carbon fiber “Panex35, manufactured by ZOLTEK, USA) "6 mm long) is particularly preferred. As a second priority, Toray Corp.'s high-performance PAN-based carbon fiber “Torayca” T500, T600, and T700 series for aircraft aircraft can also be used. Moreover, T008 series, T010 series, and TS12-006 (cut length 3-12 mm) of cut fibers for industrial use can be used as raw materials. However, this PAN-based carbon fiber (Regular Tow: 12,000-24,000 filaments / bundle) is high in performance but too expensive, and it is difficult to reduce the cost in the future depending on the production method. On the other hand, “Torayca” milled fiber MLD series (fiber length 30-150 μm) can also be used as a raw material, but the strength of the composite material is small. On the other hand, these carbon fiber industrial products generally have a relatively high carboxyl group content.
As a third priority, pitch-based carbon fiber industrial products of Kureha Co., Ltd. and Osaka Gas Chemical Co., Ltd. can also be used. These have a relatively high content of functional groups, but have a considerably low strength. Since the strength of the molded product has an isotropic advantage, it can be preferably used in the precision molding field.
Table 1 shows the specifications of carbon fibers of typical industrial products in comparison with glass fibers. If carbon fiber can be reduced in cost by mass production, it can be assumed that the advantages of weight reduction, high strength, and recyclability can be greatly exhibited compared to cheap glass fiber.

[(H) component foaming agent]
As the foaming agent (H), a microcapsule (MC), a chemical foaming agent or a masterbatch including the same, or carbon dioxide gas (including supercritical gas) can be used.
As the microcapsules, Tokuyama Sekisui Industry Co., Ltd. Advancel series (for example, P501E2 etc.) can be used. Matsumoto Microspheres: Matsumoto Yushi Seiyaku Co., Ltd .: F, FN series (for example, F-190D etc.) can be used.

[(I) Sungbun thickener]
The thickener of the present invention comprises a binder (agent A) and a binding reaction catalyst (agent B). The binder of agent A preferably has a weight average molecular weight of 1,000 to 300,000, The polymer polyfunctional epoxy compound containing 2 to 100 epoxy groups in the molecule can be used alone or as a mixture of two or more. A product in which a glycidyl group containing an epoxy ring is suspended in a resin that forms a high molecular weight skeleton in a pendant form, or a product containing an epoxy group in the molecule, such as NOF's "Murproof" series, BASF Japan Co., Ltd.'s “John Krill ADR” series can be used.
The compounding quantity of a polyfunctional epoxy compound is 0.1-5 weight part with respect to 100 weight part of polyester of (A) component. It varies greatly depending on the type and amount of carbon fiber that has a thickening effect on component (B) .In general, the effect of increasing molecular weight and melt viscosity is insufficient at less than 0.1 part by weight. Therefore, the molding processability is also insufficient and the basic physical properties and mechanical properties of the molded product are inferior.On the other hand, if it exceeds 2 parts by weight, the molding processability deteriorates, and the yellowing / coloring of the resin and the gel or fish Eye (FE) is a by-product.

[B reaction catalyst for agent B]
The binding reaction catalyst for agent B was selected from the group consisting of (1) alkali metal organic acid salts, carbonates and hydrogen carbonates, and (2) alkaline earth metal organic acid salts, carbonates and hydrogen carbonates. It is a catalyst containing at least one kind. As the organic acid salt, carboxylate, acetate and the like can be used, but stearates are particularly preferable among the carboxylates. The metal that forms the metal salt of the carboxylic acid can be an alkali metal such as lithium, sodium and potassium; an alkaline earth metal such as magnesium, calcium, strontium and barium.
The compounding amount of the carboxylate as the binding reaction catalyst is 0.01 to 1 part by weight with respect to 100 parts by weight of the component (A) polypropylene. In particular, the amount is preferably 0.1 to 0.5 part by weight. If the amount is less than 0.01 parts by weight, the catalytic effect is small, the copolymerization reaction is not achieved, and the molecular weight may not be sufficiently increased. If the amount exceeds 1 part by weight, problems such as gel generation due to local reactions and troubles in the extruder due to rapid increase in melt viscosity due to acceleration of hydrolysis are caused.

Next, the present invention will be described in detail based on examples. Evaluation methods for the polypropylene and the carbon fiber reinforced / modified polypropylene resin of the present invention are as follows.
(1) Measurement method of melt index (MI) The melt index (MI) was measured under the conditions of a temperature of 230 ° C. and a load of 2.16 kg according to the conditions of JIS K7210 (ISO 1133, ASTM D1238). However, the resin used was previously dried in hot air or vacuum at 80 ° C. for 2 hours. Or, the manufacturer's catalog value was adopted.
(2) Specific gravity measurement method According to JIS K7112 method A (submerged in water method), resin pellets or small pieces of molded articles were measured as methanol as a liquid. Or it measured also by the dimension measuring method of JISK7222.
(3) Measuring method of mechanical strength of pellets {circle around (1)} When the prototype pellets were a small amount of 1 kg or less, a small test piece was prepared and carried out.
For example, using an injection molding machine SE18DUZ manufactured by Sumitomo Heavy Industries, Ltd. (with a clamping pressure of 18 tons and a screw diameter of 16 mm), the molding temperature is 270 ° C., the mold temperature is 35 ° C., and the cooling time is 15-20 seconds. Molded.
Shape of test piece: Tensile test piece JIS K7162 5A type (thickness 2 mm)
Bending specimen strip type 80mm x 10mm (thickness 4mm)
(2) When a large amount of prototype pellets (3 kg or more), a multi-purpose test piece was prepared and carried out.
Shape of test piece: ISO20753, JIS K7139 A1 type
Length 120mm, thickness 4mm, chuck width 20mm, constriction width 10mm, length 80mm (Z runner method)
Tensile test: The tensile strength was measured at a test speed of 2 mm / min, and evaluated by an average value of 3-5 points. Young's modulus was calculated by linear regression of 25% and 75% of the maximum load (JIS K7073 and others).
Bending test: The bending strength was evaluated by an average value of 3 to 5 points by carrying out 3 point bending at a test speed of 5 mm / min.
The flexural modulus was calculated by linear regression of 25% and 75% of the maximum load (JIS K7074 et al.).
(4) Measuring method of mechanical strength of injection-molded body According to the measuring method of mechanical strength of the injection-molded body of pellets, each part of the molded body was cut out.
(5) Measuring method of physical properties of foam The measurement was performed by cutting out from the foamed molded product to a width of 10 mm.

Production example

[Production Examples of Modified Polypropylene Resin (hereinafter referred to as PP) P1, P2, P3 and P4]
[Production Example 1] P1 of modified PP; 100 parts by weight of polypropylene homopolymer pellets (hollow grade, MI 0.5: flexural modulus 1.8 GPa, Charpy impact strength 9.0 KJ / m ² ) as component A; B component 20 parts by weight of polypropylene powder (manufactured by Sun Allomer Co., Ltd., MI 0.3), C component 1 part by weight of maleic anhydride (reagent grade 1), D component dicumyl peroxide (manufactured by ALDICH) 0.100 parts by weight and 0.2 parts by weight of liquid paraffin as E component were used.
First, polypropylene powder P was charged into a tumbler, and then liquid paraffin E was added and stirred for 5 minutes, and then finely pulverized dicumyl peroxide D was added and stirred for another 5 minutes. Then, finely pulverized maleic anhydride C was added and stirred for another 5 minutes. Finally, the polypropylene homopolymer pellet A was added and stirred for 10 minutes for uniform mixing.
Using a single-screw extruder (65 mm diameter, L / D30, modified / single vent type, modified / compressed screw) manufactured by Toshiba Machine Co., Ltd., set the cylinder and die set temperature consisting of 7 blocks of this extruder. The modified polypropylene was prepared by putting the mixed composition of components A, B, C, D, and E at 170-280 ° C. into a raw material supply hopper and extruding it while measuring with a capacity-type measuring feeder to carry out reactive extrusion. Production of Resin P1 was carried out. The resin temperature was 244 ° C. and the resin pressure was 10 MPa.
The strand was continuously extruded into water from an obliquely downward nozzle having a diameter of 3 mm and cut with a rotary cutter to produce about 20 kg of translucent white resin pellets P1. The strand from the mold outlet to the water basin was bow-shaped and the melt tension was very low. The pellet shape was cylindrical and had a diameter of about 2.5 mm and a length of about 3 mm.

  [Production Example 2] P2 of modified PP; A component polypropylene homopolymer pellets, B component polypropylene powder, C component maleic anhydride and E component liquid paraffin are the same and in the same ratio. However, the modified polypropylene resin P2 was produced under the same conditions as in Production Example 1 by reducing only the ratio of the D component dicumyl peroxide to 0.050 parts by weight. The resin temperature was 241 ° C. and the resin pressure was 16 MPa. The strand was continuously extruded into water from a diagonally downward nozzle having a diameter of 3 mm and cut with a rotary cutter to produce about 20 kg of translucent white resin pellets P2. The strand from the mold outlet to the basin was almost linear, and the melt tension was fairly maintained. The pellet shape was cylindrical and had a diameter of about 2.5 mm and a length of about 3 mm.

  [Production Example 3] P3 of modified PP; A component polypropylene homopolymer pellet, B component polypropylene powder, and E component liquid paraffin are the same and in the same ratio, but the C component is anhydrous. The ratio of maleic acid is doubled to 2 parts by weight, and the ratio of the D component dicumyl peroxide is 0.075 parts by weight, intermediate between Production Examples 1 and 2, and modified polypropylene resin under the same conditions as in Production Example 1. The strand having a resin temperature of 238 ° C. and a resin pressure of 14 MPa was manufactured by continuously extruding into a water from a diagonally downward nozzle having a diameter of 3 mm, and cut with a rotary cutter to obtain a translucent white resin pellet P3 of about 20 kg. Manufactured. The strand from the mold outlet to the basin was somewhat bowed and melt tension was considerably reduced, but the water-cooled strand was significantly improved by double addition of maleic anhydride, unlike unmodified polypropylene. It was. The pellet shape was cylindrical and had a diameter of about 2.5 mm and a length of about 3 mm.

[Production Example 4] P4 of modified PP; Polypropylene block copolymer pellets as component A (hollow grade, MI 0.7: flexural modulus 1.1 GPa, Charpy impact strength 91 KJ / m ² ) 100 parts by weight, component B 20 parts by weight of polypropylene powder (manufactured by Sun Allomer Co., Ltd., MI 0.3), 2 parts by weight of maleic anhydride (reagent grade 1) as C component, 0.075 parts by weight of dicumyl peroxide as D component, E As a component, 0.2 parts by weight of liquid paraffin was used.
The modified polypropylene resin P4 was produced under the same conditions as in Production Example 1. The resin temperature was 238 ° C. and the resin pressure was 16 MPa. The strand was continuously extruded into water from an obliquely downward nozzle having a diameter of 3 mm and cut with a rotary cutter to produce about 20 kg of translucent white resin pellets P4. The strand from the mold outlet to the basin is slightly bowed and melt tension is considerably reduced, but the water-cooled strand is significantly improved in water-retaining properties due to the double addition of maleic anhydride, unlike unmodified polypropylene. It was done. The pellet shape was cylindrical and had a diameter of about 2.5 mm and a length of about 3 mm.

[Production and property evaluation of short fiber pellet NZP1-4 in which 30% of ZOLTEK carbon fiber chop (6 mm length) is mixed with P1-P4 of modified PP by side feed method]
In this conventional method, even if a carbon fiber chop (6 mm length) is used, only short fiber pellets having a remaining fiber length of 0.3 mm can be produced.
[Production Example 5-8] Short fiber pellets NZP1-4; The same direction twin screw extruder (caliber 35 mm, L / D30: modified with side feeder) manufactured by Hitachi Zosen Co., Ltd. The set temperature of the cylinder and the die comprising the block was 150 to 260 ° C. and the screw rotation speed was 150 rpm.
Using a capacity-type weighing feeder, the modified polypropylene resin pellets P1-P4 were extruded from the first hopper in each case, and the ZOLTEK carbon fiber chop was extruded from the second hopper at a rate that the carbon fiber content was 30%. Side fed continuously.
The strand was continuously extruded into water from a diagonally downward nozzle having a diameter of 3 mm and cut with a rotary cutter to produce about 5 kg of black resin pellets in each case. The strand from the mold outlet to the basin was almost linear, and the melt tension increased. The shape was cylindrical and the diameter was about 3.4 mm × length was about 6 mm. Moreover, MFR (230 degreeC, load 2.16Kg) of the short fiber pellet NZP1-4 was 1.1-4.8g / 10min. Both are suitable for extrusion molding.
[Example of Injection Molding Piece] This carbon fiber reinforced / modified pet resin black pellet NZP1-4 was dried with hot air at 80 ° C. for 2 hours to produce a hybrid injection molding machine FNZ140 (mold clamping pressure) manufactured by Nissei Plastic Industry Co., Ltd. 140 tons, screw diameter 40 mm), molding temperature 230 ° C., mold temperature 67-68 ° C., injection pressure 30-40 MPa, injection speed 160 mm / s, screw rotation speed 80 rpm and cooling time 15 seconds, The following injection molded body was molded.
Multi-purpose test piece shape: ISO 7139, JIS K7139 A1 type, total length 120 mm, thickness 4 mm, chuck portion width 20 mm, constriction portion width 10 mm,
Same length 80mm (Z runner method)

These four kinds of ZOITEK carbon fiber (CF 30%) reinforced / modified pet resin pellets showed good injection moldability with few by-products of burrs. The surface of the test piece was smooth. A test of mechanical strength at a tensile speed of 2 mm / min and a bending speed of 5 mm / min was performed. Table 4 shows the physical property values of the pellets.
The four production examples were a ZOLTEK 30% side-feed method, and the carbon fiber was easily aligned in the injection molded piece, so that a relatively large mechanical strength was observed.
NZP1 of Preparation Example 5 demonstrated a higher maximum mechanical strength value. That is, the tensile strength of 94 MPa of NZP1 is 2.4 times that of the blend of Comparative Example 3 and 3.1 times that of the polypropylene homopolymer of Comparative Example 2. The flexural modulus 15.8 GPa is 1.1 times that of the blend of Comparative Example 2 and 13.2 times that of the polypropylene homopolymer of Comparative Example 1. The other NZP2, NZP3 and NZP4 also showed superior physical properties compared to the blend of Comparative Example 2 and the polypropylene homopolymer of Comparative Example 1.

It is a SEM photograph (700 times) of a fracture surface of a Charpy impact test piece in an embodiment of the present invention. A on the left side shows a fracture surface of a Charpy impact test piece of carbon fiber reinforced / modified polypropylene (NZP1) of Production Example 5. The adhesion between the carbon fiber and the modified polypropylene is good, and the carbon fiber is frequently cut. B on the right side shows a fracture surface of a Charpy impact test piece of the blend of carbon fiber and polypropylene of Comparative Example 2. The adhesion between the carbon fiber and the polypropylene is poor, and the carbon fiber is removed from the polypropylene.

Comparative Example 1

  The catalog value of polypropylene homopolymer is used.

Comparative Example 2

  A blend of ZOLTEK carbon fiber (30%) and polypropylene homopolymer was produced by the side feed method in substantially the same manner as in Production Example 5-8. However, mixed pellets of equal amounts of polypropylene homopolymer (MI1.5) and polypropylene homopolymer (MI 30: Novatec) were used. Moreover, the injection test piece was produced in substantially the same operation, and tests, such as mechanical evaluation, were implemented.

[Manufacture of thin flat plates and foamed plates by horizontal extrusion of ZOLTEK carbon fiber (30%) reinforced / modified polypropylene resin pellets NZP5 and microcapsule foaming agent]
According to Production Example 6, approximately 50 kg of ZOLTEK carbon fiber (30%) reinforced / modified polypropylene resin black pellets NZP5 (MFR 1.5 g / 10 min: 260 ° C., load 2.16 kg) was produced.
100 parts by weight of ZOLTEK carbon fiber (30%) reinforced / modified polypropylene resin pellet NZP5, zero or 10 parts by weight of thickener masterbatch (5010E made by F-Tex), microcapsule foaming agent masterbatch (manufactured by Tokuyama Sekisui Chemical) 8 Alternatively, 12 parts by weight are mixed in advance and put into a hopper to produce a foam. A biaxial extruder (caliber: 15 mm, L / D30) manufactured by Technobel Co., Ltd. A pressure measurement sensor, air cooler, stainless steel sliding board, water basin, and take-up machine were installed. At the screw temperature of 180-250 ° C., the number of revolutions of 1150 rpm, the mold temperature of 230-250 ° C., the feed rate of the compound such as pellets is 1-2 kg / h, and the take-up speed is 1-2 m / min. Extruded horizontally. Taking into account the melt viscosity, fluidity, and shrinkage of the resin, the deformed mold has a rectangular shape (width 25 mm: center gap 2.5 mm, both ends gap 1.5 mm), and a drum shape for foam plates. (Width 25 mm: Center part gap 3.0 mm, with both ends R) was used. The test results are summarized in Table 3.
In the deformed shape by this horizontal extrusion method, as the resin pressure increases, the production of the molded body becomes more stable, and as the molded body approaches the width (25 mm) and the gap (3.0 mm) of the deformed mold, foam molding is performed. Approaches to success. In this invention, the use of the huge market of the natural wood and synthetic wood which planned about 1.5-2 times as expansion ratio is assumed.
In the manufacture of the thin flat plate of Comparative Example 3-S1, the resin pressure of the raw material NZP5 is 0.1 MPa, the melt tension of the resin is low, neck-in occurs on the left and right and top and bottom of the thin flat plate, and the compact is thin and thin. It was. In the manufacture of the thin plate of Comparative Example 3-S2, the width and thickness were increased by adding 7.5 parts of the thickener, which was considerably improved. Therefore, in the production of foamed plates of Example 1-MC1 to Example 1-MC4, the foaming test was performed with the thickener MB increased to 10. The foamed plate made of the MC foaming agent had the same width (25 mm) as that of the deformed mold, and there was no neck-in and the molding process was smooth. On the other hand, the thickness is slightly smaller than the thickness of the mold (3 mm), but it depends on the cooling conditions of the discharged foam. This can be improved by installing a female mold for dimensional adjustment. so

An example of the use of the MC molded body of the high-strength and lightweight carbon fiber chop reinforced modified pet resin of the present invention is for aircraft materials for industrial flying bodies (drones) that are currently developing rapidly. Applicable to the automotive field of a huge market in the near future. For example, the present invention can also be applied to a back door / inner panel, a radiator core support, an instrument panel, or a battery tray and cover for an electric vehicle, a fender, a roof, and the like. It is possible to reduce the weight of the electric vehicle and increase the battery loading amount, thereby extending the cruising distance, which is a weak point of the electric vehicle.
The present invention is further directed to the use of civil engineering and building materials. In addition, since further performance improvements such as radio wave absorption, conductivity, heat resistance, and heat dissipation can be achieved, the applicability in the functional material field is also great.

Claims (3)

(A) 100 parts by weight of a polypropylene resin, (B) 20 parts by weight of a polypropylene powder resin 1-2, (C) 0.1 to 3 parts by weight of an organic unsaturated acid compound, (D) 0. A composition comprising 01 to 0.50 parts by weight and (E) a spreading agent of 0.01 to 1 part by weight is reacted at a temperature equal to or higher than the melting point of polypropylene by a reactive extrusion method, and the modified polypropylene and carbon fiber chop are further reacted. (F) 5-50 parts by weight is heated and melted, and the composite material (G) in which MFR (230 ° C., load 2.16 Kg) based on JIS-K7210 method is 0.5 to 10 g / 10 min is foamed. A method for producing a foamed molded article of carbon fiber reinforced / modified polypropylene resin, which is molded by heating and melting in the presence of an agent (H).   2. The foaming of carbon fiber reinforced / modified polypropylene resin according to claim 1, wherein the foaming agent (H) contains a microcapsule, a chemical foaming agent or a masterbatch including the same, or carbon dioxide. Manufacturing method of a molded object.   A thickener (I) composed of an epoxy binder and an organometallic catalyst is added to the composite material (G), and the mixture is heated and melted in the presence of a foaming agent (H) to form. Item 2. A method for producing a foamed article of carbon fiber reinforced / modified polypropylene resin according to Item 1.

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