JP2009292861A - Polymer-molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer-molded article, fiber-reinforced with an organic polymer fiber and excellent in mechanical characteristics such as abrasion resistance, etc., by improving the close adhesion of a matrix polymer with the organic polymer fiber. <P>SOLUTION: The polymer-molded article is obtained by molding the polymer composition containing the matrix polymer, a maleic anhydride-modified polymer having a polymer chain compatible with the matrix polymer and the organic polymer fiber such as an aramid fiber, an aromatic polyester fiber or the like, treated with an aqueous alkaline solution, and having an amino group or a hydroxyl group on the surface of the fiber. The length of the organic polymer fiber is within a 0.1 to 1,000 μm range, and it is preferable that its aspect ratio is within a 10 to 10,000 range. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polymer molded body, and more particularly to a fiber reinforced polymer molded body.

  Conventionally, for example, as a means for improving the strength of a polymer molded body such as a wire coating or a connector housing, a technique of reinforcing the polymer molded body by containing fibers has been known. At this time, the adhesiveness between the contained fiber and the matrix polymer is important, and when the adhesiveness is high, the effect of reinforcing the strength of the fiber is suppressed while suppressing the deterioration of the physical properties of the polymer molded product due to the inclusion of the fiber. Demonstrated.

  Here, the fibers to be contained in the polymer molded body include inorganic fibers such as glass fibers, carbon fibers, and alumina fibers, and organic polymer fibers. Conventionally, many inorganic fibers have been used. Recently, organic polymer fibers have been attracting attention in place of inorganic fibers for the purpose of reducing the weight associated with the miniaturization of polymer molded products and improving the adhesion to matrix polymers in the polymer molded products.

  For example, Patent Document 1 discloses an example in which an aramid fiber is contained as an organic polymer fiber. At this time, as the aramid fiber, a surface-modified aramid fiber having a double bond group is used and contained in a matrix polymer made of an unsaturated polyester resin.

  Similarly, Patent Documents 2 to 4 disclose examples in which aramid fibers are contained. At this time, an epoxy group is formed on the surface of the aramid fiber, and the adhesiveness is improved by the bonding force between the epoxy group and the matrix polymer.

Japanese Examined Patent Publication No. 4-53898 JP 57-195136 A JP 59-74157 A JP 59-184234 A

  However, even if it is an organic polymer fiber, when it consists of a different kind of organic polymer from a matrix polymer, it cannot be said that the adhesiveness of the fiber and matrix polymer which are contained is enough.

  Further, the organic polymer fiber of Patent Document 1 is not satisfactory for all resins even though it is effective for adhesion to an unsaturated polyester resin. Similarly, the organic polymer fibers of Patent Documents 2 to 4 are not satisfactory for all resins.

  In particular, when the matrix polymer is an organic polymer that does not have a reactive substituent such as polyolefin, the conventional polymer molded article has insufficient adhesion between the matrix polymer and the organic polymer fiber. . And when adhesiveness is inadequate, there exists a possibility that mechanical characteristics, such as abrasion resistance, may fall.

  Further, in the case of a small polymer molded body, if the fiber is too long, there are problems that the fiber is easily exposed on the surface of the molded body and the dimensional accuracy is deteriorated. Therefore, short fibers are used in accordance with the size of the molded body, but the surface area of the fibers decreases as the fibers become shorter. For this reason, the contact area between the fiber and the matrix polymer becomes small, and the adhesion tends to be further insufficient.

  The problem to be solved by the present invention is to improve the adhesion between the matrix polymer and the organic polymer fiber in the polymer molded product reinforced with the organic polymer fiber, and to improve the mechanical properties such as wear resistance. The object is to provide an excellent polymer molded body.

  The polymer molded product according to the present invention includes a matrix polymer, a modified polymer having a polymer chain compatible with the matrix polymer, modified with carboxylic acid or acid anhydride, and a carboxylic acid group of the modified polymer. Alternatively, it is formed from a polymer composition containing an organic polymer fiber having a substituent on the surface that undergoes a condensation reaction with an acid anhydride group.

  At this time, the organic polymer fiber preferably has an amide bond or an ester bond in the molecule and an amino group or a hydroxyl group on the surface.

  And as said organic polymer fiber, the aramid fiber which has an amino group on the surface, or the aromatic polyester fiber which has a hydroxyl group on the surface can be shown suitably.

  At this time, it is desirable that the organic polymer fiber has a length in the range of 0.1 to 1000 μm and an aspect ratio in the range of 10 to 10,000.

  The polymer chain of the modified polymer is preferably made of the same kind of polymer as the matrix polymer.

  The content of the modified polymer is preferably in the range of 0.1 to 50% by mass, and the content of the organic polymer fiber is preferably in the range of 1 to 50% by mass.

  Furthermore, the modified amount of the modified polymer is preferably in the range of 0.1 to 10% by mass.

  According to the polymer molded body of the present invention, the substituent on the surface of the organic polymer fiber contained and the carboxylic acid group or acid anhydride group of the modified polymer contained undergo a condensation reaction to form a bond. Since the polymer chain of the modified polymer contained is compatible with the matrix polymer, the adhesion between the matrix polymer and the organic polymer fiber can be improved. Thereby, it is excellent in mechanical characteristics, such as abrasion resistance.

  At this time, the organic polymer fiber having an amide bond or an ester bond in the molecule and having an amino group or a hydroxyl group on the surface surely exhibits the above effect. In addition, when the organic polymer fiber is an aramid fiber having an amino group on the surface or an aromatic polyester fiber having a hydroxyl group on the surface, the above-described effect is surely obtained.

  At this time, when the length of the organic polymer fiber is in the range of 0.1 to 1000 μm and the aspect ratio is in the range of 10 to 10,000, There is no possibility of exposing the fiber to the surface of the molded body or deteriorating dimensional accuracy. Further, as described above, since the organic polymer fiber and the modified polymer are bonded and formed, and the modified polymer and the matrix polymer are compatible, the matrix polymer and the organic polymer can be used even when the fiber length is short. Adhesion with the fibers can be improved.

  When the polymer chain of the modified polymer and the matrix polymer are made of the same kind of polymer, the compatibility between the polymer chain of the modified polymer and the matrix polymer is particularly excellent.

  Moreover, when the content rate of the said modified polymer and the content rate of the said organic polymer fiber exist in the said range, it is excellent in the balance of the reinforcement effect by a fiber, and the improvement effect of the said mechanical characteristic.

  Moreover, when the modified amount of the modified polymer is within the above range, the effect of improving the mechanical properties is particularly excellent.

  Next, an embodiment of the present invention will be described in detail. The polymer molded body according to the present invention is formed from a polymer composition containing a matrix polymer, a modified polymer, and organic polymer fibers as a reinforcing material.

  The matrix polymer is not particularly limited, and examples thereof include resins, elastomers, and rubbers. These may be used alone or in combination of two or more.

  Examples of the resin include polypropylene (PP), polyethylene (PE), ethylene-methyl acrylate (EMA), ethylene-ethyl acrylate (EEA), ethylene-butyl acrylate (EBA), ethylene-methyl methacrylate (EMMA), Olefin resins such as ethylene-vinyl acetate (EVA), polyamide resins (PA), polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polysulfone resins, polyarylate resins, polyphenylene sulfide resins Examples thereof include engineering plastics such as resins, thermoplastic polyurethane resins, and polycarbonate (PC).

  Examples of elastomers include olefin elastomers (TPO, etc.), styrene elastomers (SEBS, etc.), polyamide elastomers, polyester elastomers, urethane elastomers, ionomers, fluorine elastomers, 1,2-polybutadiene, and trans-1,4- Examples thereof include thermoplastic elastomers such as polyisoprene.

  Examples of rubber include ethylene-propylene rubber (EPR), butadiene rubber (BR), and isoprene rubber (IR).

  In order to improve various physical properties, functional groups can be introduced into the resins, elastomers, and rubbers as necessary within a range that does not interfere with the physical properties. Examples of functional groups that can be introduced include carboxylic acid groups, acid anhydride groups, epoxy groups, hydroxyl groups, amino groups, alkenyl cyclic imino ether groups, and silane groups. These may be used alone or in combination of two or more.

  The modified polymer has a polymer chain that is compatible with the matrix polymer. In other words, any combination is acceptable as long as the matrix polymer and the polymer chain of the modified polymer are compatible. Examples of the polymer constituting the polymer chain include a polymer having a solubility parameter close to that of the matrix polymer and compatible with the matrix polymer. More preferably, it is the same kind of polymer as the matrix polymer. What is necessary is just to select suitably according to the kind of said matrix polymer.

  The modified polymer is a modified polymer modified with carboxylic acid or anhydride. The type of carboxylic acid or acid anhydride is not particularly limited. For example, maleic acid, maleic anhydride, fumaric acid, fumaric anhydride, phthalic acid, phthalic anhydride and the like can be exemplified. From the viewpoint of easy availability, maleic anhydride is more preferable.

  The modified polymer may be produced by, for example, a grafting method in which a monomer such as an unsaturated carboxylic acid is grafted on a polymer chain, or a copolymerization method in which a monomer that forms a polymer chain and a monomer such as an unsaturated carboxylic acid are copolymerized. The method can be formed and the method is not particularly limited. The modified polymer may be synthesized and used by the method described above, or a commercially available one may be used.

  The modification amount of the modified polymer is preferably in the range of 0.1 to 10% by mass. More preferably, it exists in the range of 0.5-5 mass%. When the modification amount is less than 0.1% by mass, the amount of the modifying group that reacts with the organic polymer fiber is small, so that the adhesion between the organic polymer fiber and the matrix polymer tends to be lowered. For this reason, the mechanical characteristics are likely to deteriorate. On the other hand, when the modification amount exceeds 10% by mass, the cost increases.

  The addition amount of the modified polymer is preferably in the range of 0.1 to 50% by mass. More preferably, it exists in the range of 0.5-30 mass%. When the addition amount is less than 0.1% by mass, the amount of the modified polymer that reacts with the organic polymer fiber is small, so that the adhesion between the organic polymer fiber and the matrix polymer tends to decrease. For this reason, the mechanical characteristics are likely to deteriorate. On the other hand, if the addition amount exceeds 50% by mass, the original physical properties of the matrix polymer are likely to be impaired. Further, the cost increases.

  The organic polymer fiber has a substituent on the fiber surface that undergoes a condensation reaction with the carboxylic acid group or acid anhydride group of the modified polymer. As such a substituent, basic substituents, such as an amino group and a hydroxyl group, can be illustrated, for example.

  In order to form such a substituent on the fiber surface, for example, an organic polymer fiber having an amide bond or an ester bond in the molecule is preferably subjected to an alkali surface treatment. A part or all of the fiber surface is hydrolyzed by the alkali surface treatment. Thereby, when it has an amide bond in the molecule, an amino group appears on the fiber surface, and when it has an ester bond in the molecule, a hydroxyl group appears on the fiber surface. In addition, the modified group of the modified polymer and the amide bond or the ester bond can be formed over a wide range of the fiber surface, and the modified polymer is compatible with the matrix polymer, thereby improving the adhesion between the organic polymer fiber and the matrix polymer. Can be increased.

  The organic polymer fiber is blended in the polymer molded body to improve the strength. Therefore, the organic polymer fiber is preferably a fiber having excellent strength. Examples of the organic polymer fiber having excellent strength and having an amide bond or an ester bond in the molecule include an aramid fiber and an aromatic polyester fiber.

  In the alkali surface treatment, the type of the surface treatment liquid is not particularly limited. For example, aqueous solutions of alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, aqueous ammonia and the like can be exemplified. More preferably, it is a strong alkaline aqueous solution having a high hydrolysis effect.

  The concentration of the alkaline substance in the surface treatment liquid is preferably in the range of 1 to 30% by mass. More preferably, it exists in the range of 2-20 mass%. When the concentration of the alkaline substance is less than 1% by mass, the hydrolysis reaction on the fiber surface tends to be insufficient. For this reason, the reaction between the organic polymer fiber and the modified polymer becomes insufficient, and the mechanical properties tend to deteriorate. On the other hand, when the concentration of the alkaline substance exceeds 30% by mass, the organic polymer fiber is excessively hydrolyzed and the physical properties of the organic polymer fiber are likely to be lowered.

  The surface treatment time is preferably in the range of 5 minutes to 10 hours. More preferably, it is in the range of 10 minutes to 3 hours. If the surface treatment time is less than 5 minutes, the hydrolysis reaction on the fiber surface tends to be insufficient. For this reason, the reaction between the organic polymer fiber and the modified polymer becomes insufficient, and the mechanical properties tend to deteriorate. On the other hand, when the surface treatment time exceeds 10 hours, the organic polymer fiber is excessively hydrolyzed and the physical properties of the organic polymer fiber are likely to be lowered.

  The surface treatment temperature is preferably in the range of 5 to 100 ° C. More preferably, it exists in the range of 20-80 degreeC. If the surface treatment temperature is less than 5 ° C., the treatment liquid may freeze, and the reaction tends to be insufficient due to a decrease in the rate of the hydrolysis reaction. For this reason, the reaction between the organic polymer fiber and the modified polymer becomes insufficient, and the mechanical properties tend to deteriorate. On the other hand, when the surface treatment temperature exceeds 80 ° C., the organic polymer fibers are easily hydrolyzed, and the physical properties of the organic polymer fibers are easily lowered.

  The addition amount of the organic polymer fiber is preferably in the range of 1 to 50% by mass. More preferably, it exists in the range of 5-30 mass%. When the addition amount is less than 1% by mass, the density of the organic polymer fiber in the polymer molded body is small, and the reinforcing effect tends to be lowered. On the other hand, if the addition amount exceeds 50% by mass, the original physical properties of the matrix polymer are likely to be impaired. Also, it tends to adversely affect the appearance and surface condition.

  The shape of the organic polymer fiber is not particularly limited. For example, either short fibers or long fibers may be used. More preferably, it is a short fiber from the viewpoint of being applicable to a small polymer molded body. The length of the short fiber is preferably in the range of 0.1 to 1000 μm. Moreover, it is preferable that an aspect ratio exists in the range of 10-10000. At this time, there is no possibility of exposing the fiber to the surface of the molded body or deteriorating dimensional accuracy.

  In such a short fiber, the surface area of the fiber is small. For this reason, the contact area between the fiber and the matrix polymer becomes small, and the adhesion tends to be further insufficient. Even in such a case, since the organic polymer fiber and the modified polymer are bonded to each other and the modified polymer and the matrix polymer are compatible, the adhesion between the matrix polymer and the organic polymer fiber can be improved. .

  In the present invention, additives generally used for polymer molded articles may be blended within a range not impairing the characteristics of the present invention. Such additives include fillers, antioxidants, metal deactivators (copper damage inhibitors), UV absorbers, UV masking agents, flame retardants, flame retardant aids, processing aids (lubricants, waxes, etc.) ), Coloring pigments and the like.

  The filler is not particularly limited. For example, metal powder, carbon black, graphite, carbon fiber, silica, alumina, titanium oxide, iron oxide, zinc oxide, magnesium oxide, tin oxide, antimony oxide, barium ferrite , Strontium ferrite, aluminum hydroxide, magnesium hydroxide, calcium sulfate, magnesium sulfate, barium sulfate, talc, clay, mica, calcium silicate, calcium carbonate, magnesium carbonate, glass fiber, calcium titanate, lead zirconate titanate, nitriding Aluminum, silicon carbide, wood fiber, fullerene, carbon nanotube, melamine cyanurate and the like can be exemplified. These may be used alone or in combination of two or more.

  Moreover, you may bridge | crosslink the polymer molded object which concerns on this invention as needed. Examples of the crosslinking means include peroxide crosslinking, silane crosslinking, electron beam crosslinking, and the like, but the means is not particularly limited.

  It does not specifically limit as a manufacturing method of the polymer molded object which concerns on this invention, A well-known manufacturing method can be used. For example, a matrix polymer, a modified polymer, an organic polymer fiber, and other additives as necessary are blended and dry blended with a normal tumbler or the like, or a Banbury mixer, a pressure kneader, A polymer composition is obtained by melting and kneading with a normal kneader such as a kneading extruder, a twin screw extruder, or a roll and uniformly dispersing. By molding the obtained polymer composition by various methods, a polymer molded body can be produced.

  For example, the covering material of the coated wire is formed by extruding the above polymer composition kneaded using a commonly used kneader such as a Banbury mixer, a pressure kneader, or a roll onto the outer periphery of the conductor using a normal extruder or the like. It can be manufactured by coating. Alternatively, a method may be used in which the outer periphery of the conductor is extrusion coated while the polymer composition is kneaded and formed with a single screw extruder or twin screw extruder.

  The use of the polymer molded body according to the present invention described above is not particularly limited. For example, covering materials for coated wires used as wiring for vehicle parts such as automobiles and electrical / electronic equipment parts, wire harness protective materials covering wire bundles, connector parts such as connector housings, medical instruments, artificial organs, Examples thereof include materials such as molecular paints and building materials.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. In this example, as one of the material characteristics, the wear resistance of the covered electric wire was evaluated.

  First, the influence of each surface treatment condition when surface treating the organic polymer fiber was investigated.

<Influence of surface treatment solution concentration>
10 g of aramid fiber chopped fiber (Teijin “Twaron 1088”, fiber length 250 μm, aspect ratio 20.8) was suspended in 200 mL of an aqueous sodium hydroxide solution and stirred at 45 ° C. for 1 hour. Thereafter, the suspension was suction filtered, and the filtrate was washed three times with pure water to remove the sodium hydroxide aqueous solution remaining on the surface. Thereafter, it was vacuum dried for 2 days to remove moisture. At this time, the sodium hydroxide concentration of the aqueous sodium hydroxide solution was adjusted to the respective concentrations shown in Table 1, and a surface-treated aramid fiber was obtained for each.

  Next, 3 g of each surface-treated aramid fiber was weighed, suspended in a 2% ninhydrin ethanol solution, and subjected to an ultrasonic wave at 50 ° C. for 30 minutes to react the amino group on the fiber surface with ninhydrin. Since ninhydrin turns purple when reacted with amino groups, it was confirmed that the fiber surface was surface-treated by discoloration. And the progress of surface treatment of the fiber surface was confirmed by measuring the light absorbency in 550 nm of the filtrate obtained by filtering reaction suspension. Table 1 shows the relationship between the concentration of sodium hydroxide aqueous solution and the absorbance. At this time, the higher the absorbance value, the greater the number of amino groups on the fiber surface, indicating that more surface treatment has been performed.

  From the results in Table 1, it can be seen that the amount of amino groups appearing on the fiber surface increases as the concentration of sodium hydroxide in the aqueous sodium hydroxide solution increases.

<Influence of surface treatment agent type>
10 g of aramid fiber chopped fiber (Teijin “Twaron 1088”, fiber length 250 μm, aspect ratio 20.8) was suspended in 200 mL of each surface treatment solution shown in Table 2 and stirred at 45 ° C. for 1 hour. Thereafter, each suspension was subjected to suction filtration, and the filtrate was washed three times with pure water to remove each surface treatment liquid remaining on the surface. Thereafter, it was vacuum dried for 2 days to remove moisture. As a result, surface-treated aramid fibers were obtained. Subsequently, the relationship between the type of the surface treatment agent and the absorbance was examined in the same manner as in the above-described <Influence of surface treatment solution concentration>. The results are shown in Table 2.

  From the results of Table 2, it was found that the surface treatment effect was the highest when the surface treatment solution was an aqueous sodium hydroxide solution and an aqueous potassium hydroxide solution. Thereby, it turned out that a strong alkaline aqueous solution is effective.

<Influence of surface treatment time>
10 g of aramid fiber chopped fiber (Teijin “Twaron 1088”, fiber length 250 μm, aspect ratio 20.8) was suspended in 200 mL of 20 mass% aqueous sodium hydroxide solution and stirred at 45 ° C. for each time shown in Table 3. did. Thereafter, each suspension was subjected to suction filtration, and the filtrate was washed three times with pure water to remove the surface treatment liquid remaining on the surface. Thereafter, it was vacuum dried for 2 days to remove moisture. As a result, surface-treated aramid fibers were obtained. Subsequently, the relationship between the surface treatment time and the absorbance was examined in the same manner as in the above-described <Influence of surface treatment solution concentration>. The results are shown in Table 3.

  From the results shown in Table 3, when an aqueous sodium hydroxide solution was used as the surface treatment solution, the amount of amino groups appearing on the fiber surface reached a plateau within a treatment time of 10 to 30 minutes. It was confirmed that the group appeared on the fiber surface.

(Example 1)
<Surface treatment of fiber>
Aramid fiber chopped fiber (“Twaron 1088” manufactured by Teijin Ltd., fiber length 250 μm, aspect ratio 20.8) was suspended in a 20 mass% aqueous sodium hydroxide solution and stirred at 45 ° C. for 30 minutes. Thereafter, the suspension was subjected to suction filtration, and the filtrate was washed three times with pure water to remove the surface treatment liquid remaining on the surface. Thereafter, it was vacuum dried for 2 days to remove moisture. Thereby, the surface treatment of the aramid fiber was performed.

<Production of covered electric wire>
90 parts by mass of polypropylene (PP) (trade name “Prime Polypro E-150GK” manufactured by Prime Polymer Co., Ltd.) and 10 parts by mass of maleic anhydride-modified polypropylene (trade name “Yumex 1010” manufactured by Sanyo Chemical Co., Ltd.) And 10 parts by mass of the surface-treated aramid fiber were put into a biaxial kneader, kneaded at 220 ° C., and then molded into a pellet by a pelletizer to obtain a polymer composition. Next, the obtained polymer composition was extrusion coated with a 0.20 mm thickness on the outer periphery of an annealed copper stranded wire conductor (cross-sectional area 0.5 mm ² ) obtained by twisting seven anodized copper wires with a φ50 mm extruder. The covered electric wire which concerns on an example was produced.

(Comparative Example 1)
A covered electric wire according to Comparative Example 1 was produced in the same manner as in Example 1 except that an aramid fiber not subjected to surface treatment was used instead of the surface-treated aramid fiber.

(Comparative Example 2)
A covered electric wire according to Comparative Example 2 was produced in the same manner as in Example 1 except that the aramid fiber was not blended in the polymer composition.

  A wear resistance test was performed on each of the coated electric wires produced as described above. The results are shown in Table 4. The test method and evaluation criteria are shown below.

(Abrasion resistance test)
In accordance with JASO D611-94, the blade reciprocation method was used. That is, the coated electric wire was cut into a length of 750 mm to obtain a test piece. Next, at a room temperature of 25 ° C., the blade was reciprocated over a length of 10 mm in the axial direction on the coating material surface of the test piece fixed on the table, and the number of reciprocations until the blade contacted the conductor due to the abrasion of the coating material Was measured. At this time, the load applied to the blade was 7 N, and the blade was reciprocated at a speed of 50 times per minute. Next, the test piece was moved 100 mm, rotated 90 degrees clockwise, and the above measurement was repeated. This measurement was performed a total of three times for the same test piece, and the lowest value was taken as the evaluation value. The case where the number of reciprocations of the blade was 500 times or more was regarded as acceptable.

  According to Table 4, as shown in the Examples, it was confirmed that when the surface-treated aramid fiber was used, the covered electric wire was excellent in wear resistance. On the other hand, as shown in the comparative example, it was found that when the aramid fiber was not used or when the aramid fiber not subjected to surface treatment was used, the covered electric wire was inferior in wear resistance.

  Therefore, if the covered wire shown in this embodiment is a wire harness including the wire bundle, the covering material will be significantly worn even if it is used in contact with other covered wires in the wire bundle. High reliability is ensured over a long period of time.

  In addition, in this example, the abrasion resistance, which is easily deteriorated due to the addition of fibers, is evaluated in the wire characteristics, but the effect of improving other wire characteristics that are deteriorated due to the adhesion between the fibers and the matrix polymer is also improved. It is thought that there is. Moreover, it is considered that not only the electric wire but also other materials such as molding materials in general or other materials have an effect of improving material properties such as mechanical properties.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

Claims (7)

A matrix polymer;
A modified polymer having a polymer chain compatible with the matrix polymer and modified with carboxylic acid or anhydride.
A polymer molded body comprising a polymer composition containing an organic polymer fiber having a substituent on the surface thereof that undergoes a condensation reaction with a carboxylic acid group or an acid anhydride group of the modified polymer.   The polymer molded body according to claim 1, wherein the organic polymer fiber has an amide bond or an ester bond in the molecule, and an amino group or a hydroxyl group on the surface.   The polymer molded body according to claim 1 or 2, wherein the organic polymer fiber is an aramid fiber having an amino group on the surface or an aromatic polyester fiber having a hydroxyl group on the surface.   4. The organic polymer fiber according to claim 1, wherein the organic polymer fiber has a length in the range of 0.1 to 1000 μm and an aspect ratio in the range of 10 to 10,000. 5. The polymer molded body described.   The polymer molded body according to any one of claims 1 to 4, wherein the polymer chain of the modified polymer is made of the same kind of polymer as the matrix polymer.   The content of the modified polymer is in the range of 0.1 to 50% by mass, and the content of the organic polymer fiber is in the range of 1 to 50% by mass. The polymer molded object of any one of Claims.   The polymer molded body according to any one of claims 1 to 6, wherein a modified amount of the modified polymer is in a range of 0.1 to 10% by mass.