Abstract:
A polyolefin resin composition comprising a polyolefin modified with an unsaturated carboxylic acid, at least one member selected from the group consisting of polyepoxides, polyisocyanates, and polyamines, and a reinforcement.

Description:
CROSS REFERENCE TO THE RELATED APPLICATION 
     This is a continuation-in-part application of application Ser. No. 450,378 filed on Dec. 16, 1982, now pending. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a composite material with improved properties which can provide a molded product having excellent various properties. 
     BACKGROUND OF THE INVENTION 
     Thermoplastic composite materials have excellent mechanical and electrical properties, and investigations for use as industrial materials have recently been developed rapidly. Of polymers constituting the composite materials, polyolefins such as polyethylene, polypropylene, and so forth have characteristics such as small specific gravity, good moldability and processability, excellent chemical resistance, and so forth, and applications of the thermoplastic composite materials comprising polyolefins as a matrix will now increase. 
     However, since polyolefins constituting the thermoplastic composite materials are nonpolar polymers, they do not have a satisfactory affinity for glass fibers, carbon fibers, carbon black, mica, talc, alumina fibers, silicon carbide fibers, aromatic polyamide fibers, and so forth which are used as a reinforcement. Therefore, a thermoplastic composite material having a further improved reinforcing effect has been demanded. 
     Many investigations have been made to develop a thermoplastic composite material satisfying the above requirement. 
     For example, Japanese Patent Application (OPI) No. 74649/1977 (the term &#34;OPI&#34; as used herein refers to a &#34;published unexamined Japanese patent application&#34;) describes a material prepared by adding 0.2 to 2 wt% of polyacrylic acid to a composite material composed of 50 to 95 parts by weight of a polyolefin and 5 to 50 parts by weight of an inorganic filler. However, this composite material cannot be said to possess sufficiently improved properties because the affinity of the matrix polymer for the filler has not yet been improved. Japanese Patent Application (OPI) No. 50041/1980 and U.S. Pat. No. 3,862,265 describe a composite material composed of a graft polyolefin and an inorganic filler which is obtained by blending an unsaturated carboxylic acid, a polyolefin, and an inorganic filler, followed by subjecting the blend to a reaction under heating and mixing in an extruder. This composite material has good affinity of the graft polyolefin for the inorganic filler but has not a sufficient flowability since it contains inorganic fibers. Therefore, a molded product prepared from this composite material has not a sufficient impact strength. Thus, composite materials having improved properties are strongly desired. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to provide a thermoplastic composite material which can provide a molded product having excellent mechanical properties (particularly, impact strength), a high flexial modulus a small specific gravity and a good water repllency. 
     Another object of the present invention is to provide a composite material having a good moldability due to its excellent flowability. 
     The composite material of the present invention comprises a modified polyolefin (i.e., a polyolefin modified with an unsaturated carboxylic acid), a reinforcement, and at least one polyfunctional compound selected from the group consisting of a polyfunctional epoxide, a polyfunctional amino compound, and a polyfunctional polyisocyanate compound. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The modified polyolefin used in the present invention can be obtained by graft-polymerizing an unsaturated carboxylic acid onto a polyolefin and has an excellent affinity for reinforcements as compared with unmodified polyolefins. 
     Examples of polyolefins used for preparation of the modified polyolefin include polyethylene, polypropylene, poly(4-methylpentene-1), ethylene/vinyl acetate copolymer, ethylene/ethyl acrylate copolymer, ethylene/propylene/diene copolymer, and so forth. When polypropylene is used, a composite material having particularly various excellent characteristics can be prepared. 
     The modifier used for preparations of the modified polyolefin is unsaturated carboxylic acids and examples thereof include acrylic acid, methacrylic acid, itaconic acid, maleic acid, and anhydrides of these acids. The amount of these modifiers used is 0.05 to 0.8 part by weight, preferably 0.1 to 0.6 part by weight, per 100 parts by weight of the polyolefin. 
     A modified polyolefin prepared using a small amount of the modifier has not a sufficient affinity for the reinforcement, making it difficult to prepare a composite material having excellent properties. On the other hand, when a modified polyolefin is prepared using a large amount of the modifier, modification of the polyolefin does not proceed sufficiently, and a modified polyolefin contains a large amount of unreacted modifier. Such a product tends to deteriorate with the passage of time. 
     The modified polyolefin can be prepared by mixing a polyolefin, a modifier, and a catalyst in predetermined proportions and reacting the resulting mixture at 150° to 280° C. for 1 to 20 minutes. When the reaction temperature and/or the reaction time exceed(s) the abovedescribed range(s), the modified polyolefin obtained shows unfavorable coloring or unnecessary thermal decomposition. 
     Examples of the catalysts used for the preparation of the modified polyolefin include benzoyl peroxide, lauroyl peroxide, and ketal or dialkyl peroxides which have a decomposition temperature necessary for attaining the half life of 10 hours of at least 80° C. Specific examples of the ketal or dialkyl peroxide catalysts include 1,1-bis(t-butylperoxy)cyclohexane, n-butyl 4,4-bis(t-butylperoxy)valerate, 1,1-bis-(t-butylperoxy)-3,3,5-trimethylcyclohexane, 2,2-bis(t-butylperoxy)butane, 2,2-bis(t-butylperoxy)octane, dicumyl peroxide, t-butylcumyl peroxide, α,α&#39;-bis(t-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, and 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3. 
     When the modified polyolefin is prepared using ketal peroxides or dialkyl peroxides having a decomposition temperature necessary for attaining the half life of 10 hours of at least 80° C., it exhibits a more effective molecular weight-lowering effect as compared with the modified polyolefin prepared using other catalysts. Accordingly, the composite material of the present invention prepared using the modified polyolefin has excellent moldability. Further, in crystallization of the polymer in the process for molding of the composite material of the present invention, the modified polyolefin prepared by using the specified ketal peroxides or dialkyl peroxides and benzoyl peroxide in a weight ratio of 10/1 to 1/10, preferably 1/6 to 6/1, exhibits an effect of inhibiting the growth of spherulites and, as a result, a composite material having good characteristics (a spherulite size of 50μ or less, preferably 5 to 30μ) can be obtained. 
     The amount of the catalyst used is 0.03 to 3 parts by weight, preferably 0.05 to 1 part by weight, per 100 parts by weight of the polyolefin. 
     As a modification reaction of the polyolefins, a solution reaction process using a solvent as a reaction medium or a method in which the reaction is conducted in a heat-melting state can be employed. From the standpoint of prevention of unnecessary coloring of the modified polyolefin obtained, prevention of unnecessary lowering of the molecular weight of the polyolefin, and the choice of an appropriate reaction time, it is preferred to employ a heat-melting reaction using an extruder as a reactor. 
     Polyfunctional epoxy compounds used in the present invention are compounds having two or more epoxy groups in the molecule. Examples thereof include a bisphenol A type epoxy compound, a bisphenol F type epoxy compound, an aliphatic ether type epoxy compound, a novolak type epoxide, an isocyanurate type epoxide and so forth. Specific examples thereof include condensates between bisphenol A and epichlorohydrin; polyglycidyl ethers of polyols such as ethylene glycol, propylene glycol, polyethylene glycol, glycerol, neopentyl glycol, trimethylolpropane, and sorbitol; triglycidyl isocyanurate, N-methyl-N&#39;,N&#34;-diglycidyl isocyanurate, and triglycidyl cyanurate. The molecular weight of these polyfunctional epoxides is, though not particularly limited, about 4,000 or less. 
     Polyfunctional amines used in the present invention are compounds having two or more amino groups in the molecule. Specific examples thereof include hexamethylenediamine, tetramethylenediamine, methaxylenediamine, diaminodiphenylmethane, diaminodiphenyl sulfone, 3,3&#39;-diaminobenzidine, isophthalic acid hydrazide, diaminodiphenyl ether, nanomethylenediamine, and diethylenetetramine. 
     Polyfunctional isocyanates are compounds having two or more isocyanate groups in the molecule. Examples thereof include tetramethylene diisocyanate, toluidine diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, and their polyisocyanates obtained by extending them with a chain-extending agent. Of these polyfunctional compounds, polyepoxides having a cyanuric or isocyanuric ring have high reactivity toward the modified polyolefin in the process of preparing the composite material of the present invention and a molding product prepared from the composite material thus-obtained has more excellent impact strength as compared with other molded products. 
     Polyfunctional epoxides, polyfunctional amines, and polyfunctional isocyanates can be used alone or in combination, the amount thereof is each 0.03 to 5 wt% per the weight of the modified polyolefin but the total amount does not exceed 10 wt% per the weight of the modified polyolefin. 
     Molded products prepared from the composite material containing at least one of those polyfunctional amines, polyfunctional isocyanates, and polyfunctional epoxides of the present invention have an excellent strength characteristic as compared with molded products prepared from composite materials containing no those polyfunctional compounds. 
     Reinforcements used in the present invention are fibrous materials such as glass fibers, carbon fibers, graphite fibers, aromatic polyamide fibers, silicon carbide fibers, polysulfone type fibers, polyether ketone fibers, alumina fibers, potassium titanate fibers, asbestos fibers, boron fibers, metal fibers, and so forth. Fibers having the length of 5 mm or less, preferably 0.01 to 3 mm, are preferred. 
     As other reinforcements, powdery or flaky materials such as glass flakes, talc, mica, kaolin, clay, diatomaceous earth, calcium carbonate, calcium sulfate, magnesium oxide, carbon black, titanium oxide, metal powders, alumina, graphite, white carbon, wollastonite, molybdenum disulfide, and tungsten disulfide can be used. Those reinforcements are incorporated in the modified polyolefin alone or in combination thereof in an amount of 5 to 400 wt% per the weight of the modified polyolefin. If the amount of the reinforcement is too small, a sufficient reinforcing effect, high flexial modulus and high strength cannot be obtained. On the other hand, if the amount of the reinforcement is too large, moldability of the composite material is remarkable reduced and the mechanical properties of a molded product prepared from the composite material tend to deteriorate. 
     Other thermoplastic plastics, for example, engineering plastics such as polyamides, unmodified polyolefins, polyesters, polycarbonates, polyacetals, and polysulfones can be incorporated into the composite material of the present invention, if desired. 
     The composite material of the present invention is prepared by blending a modified polyolefin, at least one compound selected from the group consisting of polyfunctional epoxides, polyfunctional amines, and polyfunctional isocyanates, and a reinforcement in the predetermined proportions. This composite material can be molded into the desired molded product by an injection molding method or the like. 
     Moldability of the composite material of the present invention is superior to that of similar kinds of conventional composite materials. Thus, it is believed that a molded product prepared from the composite material of the present invention has sufficiently improved impact strength as compared with that prepared from similar kinds of conventional composite materials. 
    
    
     The present invention will now be explained in detail by reference to the following non-limiting examples. Unless otherwise indicated, all percents, parts, ratios and the like are by weight. 
     EXAMPLE 1 
     To 100 parts by weight of polypropylene powders having an inherent viscosity of 1.5 (measured in a tetralin solution at 135° C.) were added modifiers and peroxides with the amounts as shown in Table 1, and the mixture was blended in the Henschel mixer. The mixture was then fed into an extruder reactor of 30 φ and L/D=25, and modified in a mixed state under heat-melting at a reaction temperature of 230° C. for a reaction time of 7 minutes. The unreacted modifier was removed by reducing the pressure of the vent portion of the extruder, and then the reaction mixture was extruded into pellets to give modified polyolefins. 
     To 100 parts by weight of the resulting modified polyolefin pellets were each added prescribed amounts of reinforcements and polyfunctional compounds as shown in Table 1. The mixture was blended in a tumbler and melt mixed in an extruder, and extruded therefrom to give pellets of composite materials. 
     These composite materials were formed into 3 kinds of molded products, viz., plates of No. 1 dumbbell, 125×12.5×3.2 (mm), and 125×12.5×6.4 (mm) using a screw on-line type injection machine under molding conditions of a cylinder temperature of 220° C. and a mold temperature of 60° C. 
     The results obtained by measuring fabrication properties of the composite materials and mechanical properties of the molded products therefrom under the following conditions are shown in Table 1. 
     Melt Flow Index (molding flow index): ASTM-D-1238, load 2.16 kg, temperature 230° C. 
     Izod Impact Strength: ASTM-D-256. 
     Heat Distortion Temperature (hereinafter referred to as HDT): ASTM-D-648. ##EQU1## 
     
                                           TABLE 1__________________________________________________________________________         Experiment No.         1       2      3      4      5      6     7__________________________________________________________________________Composition of compositematerialPolypropylene 100     100    100    100    100    100   100Parts by weightPeroxideKind          --      Benzoyl                        --     Benzoyl                                      Benzoyl                                             Benzoyl                                                   Benzoyl                 peroxide      peroxide                                      peroxide                                             peroxide                                                   peroxideParts by weight         --      0.3    --     0.3    0.3    0.3   0.3ModifierKind          --      Maleic --     Maleic Maleic Maleic                                                   Acrylic                 anhydride     anhydride                                      anhydride                                             anhydride                                                   acidParts by weight         --      0.3    --     0.3    0.3    0.3   0.3Polyfunctional compoundKind          --      --     Hexa-  Hexa-  Hexa-  --    --                        methylene                               methylene                                      methylene                                             diamino                        diamine                               diamine                                      diamine                                             diphenyl                                             etherParts by weight         --      --     0.3    0.3    0.3    0.5   --ReinforcementKind          Carbon  Carbon Carbon Carbon Carbon Carbon                                                   Carbon         fiber   fiber  fiber  fiber  fiber  fiber fiberParts by weight         25      25     25     25     25     25    25Mechanical property ofmolded productFlexial strength         770     1,140  820    1,470  1,540  1,460 1,160(kg/cm.sup.2)Flexial modulus         8.8     8.8    8.8    8.8    8.7    8.7   8.6(× 10.sup.4 kg/cm.sup.2)Izod impact strength         15      18     16     31     33     28    17(kg-cm/cm.sup.2)HDT (°C.)         145     148    145    147    143    145   148Ratio of improvement in         1.0     1.5    1.1    1.9    2.0    1.9   1.5strength (ratio)Remark        Comparative                 &#34;      &#34;      Invention                                      Invention                                             Invention                                                   Comparative         Example                                   Example__________________________________________________________________________         Experiment No.         8      9      10     11     12     13     15__________________________________________________________________________Composition of compositematerialPolypropylene 100    100    100    100    100    100    100Parts by weightPeroxideKind          Benzoyl                Benzoyl                       Benzoyl                              Benzoyl                                     Benzoyl                                            Benzoyl                                                   Benzoyl         peroxide                peroxide                       peroxide                              peroxide                                     peroxide                                            peroxide                                                   peroxideParts by weight         1.0    0.3    1.0    0.3    0.3    0.3    0.3ModifierKind          Acrylic                Acrylic                       Acrylic                              Maleic Maleic Maleic Maleic         acid   acid   acid   anhydride                                     anhydride                                            anhydride                                                   anhydrideParts by weight         0.7    0.3    0.7    0.3    0.3    0.3    0.3Polyfunctional compoundKind          --     Hexa-  Hexa-  2,4-   4,4&#39;-  Triglycidyl                                                   Bisphenol A                methylene                       methylene                              Toluilene                                     Diphenyl-                                            isocyanurate                                                   diglycidyl                diamine                       diamine                              diisocyanate                                     methane       ether                                     diisocyanateParts by weight         --     0.3    0.3    0.3    0.3    0.3    0.3ReinforcementKind          Carbon Carbon Carbon Carbon fiber                                     Carbon fiber                                            Carbon                                                   Carbon         fiber  fiber  fiber                       fiberParts by weight         25     25     25     25     25     25     25Mechanical property ofmolded productFlexial strength         1,230  1,460  1,570  1,530  1,550  1,580  1,460(kg/cm.sup.2)Flexial modulus         8.6    8.7    8.8    8.4    8.6    8.9    8.6(× 10.sup.4 kg/cm.sup.2)Izod impact strength         19     29     27     34     33     32     28(kg-cm/cm.sup.2)HDT (°C.)         147    147    149    146    145    151    150Ratio of improvement in         1.6    1.9    2.0    2.0    2.0    2.1    1.9strength (ratio)Remark        Comparative                Invention                       Invention                              Invention                                     Invention                                            Invention                                                   Invention         Example__________________________________________________________________________        Experiment No.        16    17     18     19      20      21     22__________________________________________________________________________Composition of compositematerialPolypropylene        100   100    100    100     100     100    100Parts by weightPeroxideKind         Benzoyl              Benzoyl                     Benzoyl                            Benzoyl Benzoyl Benzoyl                                                   --        peroxide              peroxide                     peroxide                            peroxide                                    peroxide                                            peroxideParts by weight        0.3   0.3    0.3    0.3     0.3     0.3    --ModifierKind         Maleic              Maleic Maleic Maleic  Acrylic Acrylic                                                   --        anhydride              anhydride                     anhydride                            anhydride                                    acid    acidParts by weight        0.3   0.3    0.3    0.3     0.3     0.3    --Polyfunctional compoundKind         Neopentyl-              --     Triglycidyl                            Hexamethylene                                    Hexamethylene                                            Triglycidyl                                                   --        glycol di-   isocyanurate                            diamine diamine isocyanurate        glycidyl        etherParts by weight        0.3   --     0.3    0.3     0.3     0.3    --ReinforcementKind         Carbon              Glass  Glass fiber                            Glass fiber                                    Glass fiber                                            Carbon Talc        fiber fiber                         fiberParts by weight        25    25     25     25      25      25     25Mechanical property ofmolded productFlexial strength        1,500 1,080  1,330  1,280   1,250   1,600  430(kg/cm.sup.2 )Flexial modulus        8.7   5.3    5.5    5.4     5.3     8.5    4.3(× 10.sup.4 kg/cm.sup.2)Izod impact strength        30    20     25     27      28      30     10(kg-cm/cm.sup.2)HDT (°C.)        151   145    144    145     148     149    80Ratio of improvement in        1.9   1.2    1.5    1.5     1.4     2.1    1.0strength (ratio)Remark       Invention              Comparative                     Invention                            Invention                                    Invention                                            Invention                                                   Comparative              Example                              Example__________________________________________________________________________         Experiment No.         23      24          25     26     27      28__________________________________________________________________________Composition of compositematerialPolypropylene 100     100         100    100    100     100Parts by weightPeroxideKind          Benzoyl Benzoyl peroxide                             Benzoyl                                    Benzoyl                                           Benzoyl Benzoyl         peroxide            peroxide                                    peroxide                                           peroxide                                                   peroxideParts by weight         0.3     0.3         0.3    0.3    0.3     0.7ModifierKind          Maleic  Maleic anhydride                             Maleic Maleic Maleic  Maleic         anhydride           anhydride                                    anhydride                                           anhydride                                                   anhydrideParts by weight         0.3     0.3         0.3    0.3    0.3     0.7Polyfunctional compoundKind          --      4,4-Diphenylmethylene                             Triglycidyl                                    Triglycidyl                                           Triglycidyl                                                   Triglycidyl                 diisocyanate                             isocyanurate                                    isocyanurate                                           isocyanurate                                                   isocyanurateParts by weight         --      0.5         0.3    0.3    0.3     0.3ReinforcementKind          Talc    Talc        Talc   Glass fiber                                           Talc/carbon                                                   Carbon fiber                                           fiber = 1/1Parts by weight         25      25          25     25     50      25Mechanical property ofmolded productFlexial strength         500     560         540    1,320  1,530   1,640(kg/cm.sup.2)Flexial modulus         4.3     4.3         4.5    5.4    10.1    8.2(× 10.sup.4 kg/cm.sup.2)Izod impact strength         10      19          17     27     29      32(kg-cm/cm.sup.2)HDT (°C.)         80      82          80     148    149     149Ratio of improvement in         1.0     1.3         1.3    1.5    2.0     2.1strength (ratio)Remark        Comparative                 Invention   Invention                                    Invention                                           Invention                                                   Invention         Example__________________________________________________________________________         Experiment No.         29      30      31       32      33      34__________________________________________________________________________Composition of compositematerialPolypropylene 100     100     100      100     100     100Parts by weightPeroxideKind          1,1-Bis(t-                 2,5-Dimethyl-                         Benzoyl  *1      *2      *2         butylperoxy)-                 2,5-di(t-                         peroxide         3,3,5-  butylperoxy)-         trimethyl-                 hexyne-3         cyclohexaneParts by weight         0.2     0.2     0.       0.2     0.2     0.2ModifierKind          Maleic  Maleic  Maleic   Maleic  Maleic  Maleic         anhydride                 anhydride                         anhydride                                  anhydride                                          anhydride                                                  anhydrideParts by weight         0.3     0.3     0.3      0.3     0.3     0.3Polyfunctional compoundKind          Triglycidyl                 Triglycidyl                         Triglycidyl                                  Triglycidyl                                          Triglycidyl                                                  Triglycidyl         isocyanurate                 isocyanurate                         isocyanurate                                  isocyanurate                                          isocyanurate                                                  isocyanurateParts by weight         0.3     0.3     0.3      0.3     0.3     0.3ReinforcementKind          Carbon fiber                 Carbon fiber                         Carbon fiber                                  Carbon fiber                                          Carbon fiber                                                  Carbon fiberParts by weight         25      25      25       25      25      25Mechanical property ofmolded productFlexial strength         1,480   1,450   770      1,500   1,560   1,470(kg/cm.sup.2)Flexial modulus         8.7     8.7     8.4      8.6     8.7     8.6(× 10.sup.4 kg/cm.sup.2)Izod impact strength         29      20      11       35      33      17(kg-cm/cm.sup.2)HDT (°C.)         144     146     141      148     149     145Ratio of improvement in         1.9     1.4     1.0      1.9     2.0     1.9strength (ratio)Remark        Invention                 Invention                         Comparative                                  Invention                                          Invention                                                  Invention                         ExampleMFI (g/10 min)        39.9    6.1Spherical size (μ)         100     100     100      10      10      100Moldability into flat         Better  Best    Bad      Better  Better  Betterplate 1 mm thick__________________________________________________________________________         Experiment No.         35      36       37     38      39      40__________________________________________________________________________Composition of compositematerialPolypropylene 100     100      100    100     100     100Parts by weightPeroxideKind          --      Benzoyl  Benzoyl                                 Benzoyl *1      *1                 peroxide peroxide                                 peroxideParts by weight         --      0.2      0.2    0.2     0.2     0.2ModifierKind          --      Maleic   Maleic Maleic  Maleic  Maleic                 anhydride                          anhydride                                 anhydride                                         anhydride                                                 anhydrideParts by weight         --      0.3      0.3    0.3     0.3     0.3Polyfunctional compoundKind          Triglycidyl                 Triglycidyl                          Hexa-  Bisphenol A                                         Triglycidyl                                                 Hexamethylene         isocyanurate                 isocyanurate                          methylene                                 diglycidyl                                         isocyanurate                                                 diamine                          diamine                                 etherParts by weight         0.3     0.6      0.6    0.6     0.6     0.6ReinforcementKind          Carbon fiber                 Carbon fiber                          Carbon Carbon  Carbon fiber                                                 Carbon fiber                          fiber  fiberParts by weight         25      25       25     25      25      25Mechanical property ofmolded productFlexial strength         750     1,750    1,520  1,510   1,700   1,480(kg/cm.sup.2)Flexial modulus         8.3     8.6      8.5    8.7     8.7     8.6(× 10.sup.4 kg/cm.sup.2)Izod impact strength         13      40       33     30      38      30(kg-cm/cm.sup.2)HDT (°C.)         141     145      144    146     146     145Ratio of improvement in         1.0     2.3      2.0    2.0     2.2     1.9strength (ratio)Remark        Comparative                 Invention                          Invention                                 Invention                                         Invention                                                 Invention         ExampleMFI (g/10 min)         5.6Spherical size (μ)         100     10       10     10      10      10Moldability into flat         Bad     Good     Good   Good    Best    Bestplate 1 mm thick__________________________________________________________________________         Experiment No.         41      42      43      44      45       46__________________________________________________________________________Composition of compositematerialPolypropylene 100     100     100     100     100      100Parts by weightPeroxideKind          *1      --      Benzoyl --      Benzoyl  Benzoyl                         peroxide        peroxide peroxideParts by weight         0.2     --      0.3     --      0.3      0.3ModifierKind          Maleic  --      Maleic  --      Maleic   Maleic         anhydride       anhydride       anhydride                                                  anhydrideParts by weight         0.3     --      0.3     --      0.3      0.3Polyfunctional compoundKind          Bisphenol A                 --      --      Triglycidyl                                         Triglycidyl                                                  Triglycidyl         diglycidyl              isocyanurate                                         isocyanurate                                                  isocyanurate         etherParts by weight         0.6     --      --      0.3     0.3      3.0ReinforcementKind          Carbon  Carbon  Carbon  Carbon  Carbon   Carbon         fiber   fiber   fiber   fiber   fiber    fiberParts by weight         25      100     100     100     100      100Mechanical property ofmolded productFlexial strength         1,470   990     1,450   950     1,950    2,110(kg/cm.sup.2)Flexial modulus         8.6     21.5    22.0    21.8    22.2     27.3(× 10.sup.4 kg/cm.sup.2)Izod impact strength         29      10      17      11      28       25(kg-cm/cm.sup.2)HDT (°C.)         146     149     148     148     148      149Ratio of improvement in         1.9     1.0     1.5     1.0     2.0      --strength (ratio)Remark        Invention                 Comparative                         &#34;       &#34;       Invention                                                  Invention                 ExampleMFI (g/10 min)         10      3       6       3       5Spherical size (μ)         10Moldability into flat         Bestplate 1 mm thick__________________________________________________________________________         Experiment No.         47     48      49      50       51       52__________________________________________________________________________Composition of compositematerialPolypropylene 100    100     100     100      100     100Parts by weightPeroxideKind          Benzoyl                Benzoyl Benzoyl --       --      --         peroxide                peroxide                        peroxideParts by weight         0.3    0.3     0.3     --       --      --ModifierKind          Acrylic                Maleic  Maleic  --       Maleic  --         acid   anhydride                        anhydride        anhydrideParts by weight         0.3    0.3     0.3     --       0.3     --Polyfunctional compoundKind          Triglycidyl                Hexameth-                        4,4&#39;-diphenyl                                --       --      Triglycidyl         isocyanu-                ylene   methane                  isocyanurate         rate   diamine diisocya-                        nateParts by weight         0.3    0.3     0.3     --       --      0.3ReinforcementKind          Carbon Carbon  Carbon  Glass    Glass   Glass fiber         fiber  fiber   fiber   fiber    fiberParts by weight         100    100     100     100      100     100Mechanical property ofmolded productFlexial strength         1,900  1,870   1,810   1,000    1,240   970(kg/cm.sup.2)Flexial modulus         22.0   21.6    22.3    15.0     15.2    15.1(× 10.sup.4 kg/cm.sup.2)Izod impact strength         27     26      28      12       19      13(kg-cm/cm.sup.2)HDT (°C.)         149    148     147     148      149     148Ratio of improvement in         1.9    1.9     1.8     1.0      1.2     1.0Remark        Invention                Invention                        Invention                                Comparative                                         Comparative                                                 Comparative                                Example  Example Example__________________________________________________________________________         Experiment No.         53      54      55      56       57      58__________________________________________________________________________Composition of compositematerialPolypropylene 100     100     100     100      100     100Parts by weightPeroxideKind          Benzoyl 1,1-Bis(t-                         *1      --       Benzoyl Benzoyl         peroxide                 butylperoxy)-            peroxide                                                  peroxide                 3,3,5-                 trimethyl-                 cyclohexaneParts by weight         0.3     0.3     0.3     --       0.3     0.3ModifierKind          Maleic  Maleic  Maleic  --       Maleic  Maleic         anhydride                 anhydride                         anhydride        anhydride                                                  anhydrideParts by weight         0.3     0.3     0.3     --       0.3     0.3Polyfunctional compoundKind          Triglycidyl                 Triglycidyl                         Triglycidyl                                 --       --      Triglycidyl         isocyanurate                 isocyanurate                         isocyanurate             isocyanurateParts by weight         0.3     0.3     0.3     --       --      0.3ReinforcementKind          Glass fiber                 Carbon fiber                         Carbon fiber                                 Calcium  Calcium Calcium                                 carbonate                                          carbonate                                                  carbonateParts by weight         100     100     100     100      100     100Mechanical property ofmolded productFlexial strength         1,590   1,850   1,920   390      510     600(kg/cm.sup.2)Flexial modulus         15.0    22.0    22.1    5.4      5.4     5.3(× 10.sup.4 kg/cm.sup.2)Izod impact strength         24      22      27      8        9       16(kg-cm/cm.sup.2)HDT (°C.)         149     148     149     80       80      80Ratio of improvement in         1.6     1.9     1.9     1.0      1.3     1.5strength (ratio)Remark        Invention                 Invention                         Invention                                 Comparative                                          Comparative                                                  Invention                                 Example  ExampleMFI (g/10 min)        14      12__________________________________________________________________________ Notes *1: A mixture of benzoyl peroxide and 1,1bis(t-butylperoxy)-3,3,5-trimethylcyclohexane (1:1) *2: A mixture of benzoyl peroxide and 2,5dimethyl-2,5-di(t-butylperoxy)hexyne-3 (1:1) 
    
     EXAMPLE 2 
     To 100 parts by weight of polypropylene powders having an inherent viscosity of 2.0 (measured in a tetralin solution of 135° C.) were each added peroxides as shown in Table 2 and 0.3 part of maleic anhydride as a modifier, and the mixture was blended uniformly in the Henschel mixer. The mixture was then subjected to a heat-melting reaction under conditions of a reaction temperature of 250° C. and a reaction time period of 7 minutes. 
     The results obtained by measuring the inherent viscosity of modified polypropylenes thus-obtained are shown in Table 2 below. 
     
                       TABLE 2______________________________________        Inherent Viscosity        Amount of Peroxide Added (parts)Peroxide       0      0.05   0.1  0.3  0.4  0.8______________________________________Benzoyl peroxide          1.75   1.73   1.70 1.62 1.6  1.561,1-Bis(t-butylperoxy)-          1.75   1.45   1.3  1.00 0.95 --3,3,5-trimethyl cyclo-hexaneDicumyl peroxide          1.75   1.08   1.32 1.08 0.98 --Benzoyl peroxide/1,1-          1.75   --     1.31 1.09 --   --Bis(t-butylperoxy)-3,3,5-trimethyl cyclohexane (1:1weight ratio mixture)______________________________________ 
    
     While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.