JPH0473368B2 - - Google Patents

Description

[Detailed description of the invention]

"Industrial Application Field" The present invention relates to a method for manufacturing a polyamide resin molded article. More specifically, it relates to a method for producing glass fiber reinforced polyamide cast molded products and reflective injection molded products. The present invention relates to a method for manufacturing a molded product that has good rigidity and a glossy surface, and has less distortion due to the orientation of glass fibers and less anisotropy in mechanical properties. "Prior art" In recent years, a method of injecting or injecting a highly reactive liquid raw material into a mold, polymerizing and molding it into the mold to directly obtain a molded product, the so-called reaction injection molding method or casting molding method, has been developed. Attention has been paid. Conventionally, polyurethane molded products have made great progress using the above molding method, but recently,
New materials such as polyamides, unsaturated polyesters, and epoxies are also beginning to be used. Among them, polyamide has excellent toughness, high rigidity, heat resistance, and good friction resistance and wear characteristics. Furthermore, polyamide has good fluidity of the raw material composition and low heat generation during polymerization, so it has low heat resistance. It is possible to mold with injection pressure,
It is attracting particular attention as a material for reaction injection molding and pouring molding because it has good transferability on the mold surface and can be used to form thin to thick molded products at will. In order to take advantage of these characteristics of polyamide and provide even higher rigidity and heat resistance, a method of adding glass fiber as a reinforcing material is used. The glass fibers added to the raw material compositions used in reaction injection molding or cast molding are often milled or cut glass fibers. When a raw material composition containing the above-mentioned glass fiber as a reinforcing material is used, the rigidity and heat resistance of the molded article are certainly improved significantly. However, on the other hand, it significantly increases the viscosity of the raw material composition and narrows the range of molding conditions, and at the same time, it impairs the gloss of the surface of the molded product and causes distortion and mechanical properties of the molded product due to the orientation of glass fibers. The occurrence of anisotropy is also remarkable. The appearance of polyamide-based reaction injection molded products and cast molded products is characterized by an extremely good appearance compared to, for example, reaction injection molded products such as polyurethane, or cast molded products, and furthermore, they can be easily painted afterward. This is a great advantage as it provides a good appearance when processed. Therefore, it is desired to develop a molded product that maintains these excellent characteristics and also has excellent rigidity and heat resistance by using glass fiber as a reinforcing material. "Problems that the invention attempts to solve" The problems that the invention attempts to solve are as follows. (1) In the method of manufacturing molded products using polyamide reaction injection molding method and main molding method, the viscosity of the raw material composition is low during molding even though glass fiber is blended into the raw material. To provide a method that is easy to handle and mold. (2) Molded products produced by polyamide reaction injection molding and casting molding have excellent rigidity, a glossy surface, and are free from distortion caused by the orientation of glass fibers.
and to provide a method for reducing anisotropy in mechanical properties. "Means for Solving the Problems" The gist of the present invention is that when manufacturing polyamide resin molded products, ω containing a polymerization catalyst is used.
- Either or both of the lactam melt and the omega-lactam melt containing the polymerization cocatalyst contain 3% by weight or less of fibers with a fiber length of less than 25 μm, or 300 μm.
30% by weight or less of glass fibers having a weight average fiber length of 75 μm to 125 μm, which is injected or injected into a mold to form a molded product. The invention consists in a method for manufacturing resin molded products. The present invention will be explained in detail below. In polyamide-based reaction injection molding or injection molding, several types of raw materials used are divided into two or more component compositions and prepared, and at the time of molding, these two or more component compositions are Polymerization and molding are performed simultaneously in a mold by combining by collision mixing or by a static mixer, dynamic mixer, etc. In polyamide reaction injection molding or injection molding, one component system (hereinafter referred to as component system (A)) of a two-component raw material composition is a melt of a polymerization catalyst and an ω-lactam, and the other component system is The component system (referred to as (B)) consists of a polymerization cocatalyst, various additives, and an omega-lactam melt. The glass fiber used in the present invention is based on
It can be added to either (A) or component system (B), or it can be added to both component systems (A) and (B) at the same time. The glass fibers used in the present invention may be crushed or shredded glass fibers, that is, milled glass fibers or cut glass fibers, and are not particularly limited. The weight is 3% by weight or less, and the weight of items exceeding 300 μm is 30% by weight
or less, and the weight average fiber length is from 75μm
The essential requirement is that the thickness be up to 125 μm. If it exceeds these ranges, there will be the following disadvantages. In other words, if the content of fibers with a length of less than 25 μm exceeds 3% by weight, it contributes to lowering the viscosity of the composition or improving the appearance of the molded product obtained, but it does not improve the rigidity of the molded product obtained. Not enough. In addition, if the fiber length exceeds 300 μm exceeds 30% by weight, it contributes to improving the rigidity of the obtained molded product, but the viscosity of the composition increases significantly and the molded product becomes difficult to form. Extremely deteriorates appearance. Poor appearance of molded products is exclusively caused by
It is produced by glass fibers exceeding 300 μm. The diameter of the glass fiber used in the present invention refers to the diameter (also called fineness) of a single glass fiber, and is expressed by symbols commonly used in the industry: D, E,
F, G, H, J, K, L, M, N, P, Q, R,
S, T, U, that is, from 5.08 μm to 25.4 μm. Although diameters smaller than this cannot be used, they have very low bulk specific gravity, are inconvenient to handle, and have low spinning productivity, making them extremely expensive, making them unsuitable for practical use from an economic standpoint. do not have.
On the other hand, glass fibers with a diameter exceeding 25.4 μm have a small ratio of fiber length to fiber diameter (referred to as aspect ratio), and the expected improvement in the rigidity of molded products cannot be observed, making them unsuitable for practical use. The composition of the glass fiber is not particularly limited. Glass called E-glass is generally used for milled glass fiber or cut glass fiber, but it is also treated with concentrated sulfuric acid to remove acid-soluble components, such as leached glass and C-glass, which has strong acid resistance.
Glass, furthermore A glass, S glass, M glass,
Known glasses such as AR glass and L glass can be used. Glass fibers for resin reinforcement generally include:
In order to provide good interfacial adhesion with the matrix resin, the fiber surface is treated with a surface treatment agent. In the present invention, for example, chromium-based surface treatment agents such as methacrylate-chromic chloride, vinyl-tri-ethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, cationic methacrylate Functional silane, γ-aminopropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, phenyltrimethoxysilane , N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, chloropropylmethoxysilane and other silane surface treatment agents, isopropyltriisostearoyl titanate, isopropyltridecylbenzenesulfonyl titanate, isopropyltris (dioctylpyrophosphate) ) Titanate,
Tetraisopropyl bis(dioctylphosphite) titanate, isopropyltrioctanoyl titanate, isopropyl dimethacrylylisostearoyl titanate, isopropyl tricumyl phenyl titanate, isopropyl tri(N-aminoethyl-aminoethyl) titanate, dicumyl phenyloxyacetate titanate, dicumyl phenyloxyacetate titanate, Glass fibers treated with known surface treatment agents such as isostearoyl ethylene titanate and other titanate surface treatment agents may be used. However, since the effect of untreated glass fiber is recognized in the present invention, it is not essential to use glass fiber treated with a surface treatment agent. Therefore, the amount of glass fiber blended is not particularly limited, but in actual blending, it is preferably 0 parts by weight per 100 parts by weight of either component system (A) or (B). From not blending at all to a maximum of 120 parts by weight, and component systems (A) and (B)
It is used in an amount between 1 part by weight and 50 parts by weight based on 100 parts by weight of all of the glass fibers. Although it is possible to use more than 120 parts by weight of component system (A) or component system (B) in an amount exceeding 120 parts by weight, when such a large amount of glass fiber is used, the viscosity of the raw material composition increases significantly, and when reaction injection molding is performed, a high injection pressure is required, and one of the advantages of polyamide reaction injection molding, which is that it can be molded at a relatively low injection pressure, cannot be achieved. Further, it is not preferable because there are inconveniences such as frequent clogging of the constriction part of the mixing head or the injection machine or piping. In addition, if the total amount of glass fiber exceeds 50 parts by weight relative to the total amount of component system (A), component system (B), and the three glass fiber components, the surface roughness of the molded product will increase, and , which is not preferred in practice because a brittle molded product is obtained. Similarly, in the case of cast molding, raw material compositions containing more than 50 parts by weight of glass fibers have too high a viscosity, resulting in the following drawbacks. That is, the air bubbles that are caught up during mixing cannot be completely removed, and the air bubbles remain in the molded product, resulting in a defective product. In addition, in the case of a rather complicated mold, gas remains in the mold and unfilled parts are formed, resulting in a defective molded product and impairing the good mold transferability of polyamide cast molding. Furthermore, in cast rotational molding, if the viscosity of the raw material composition is high, the wall thickness of the molded product will be uneven, resulting in a defective molded product. Specific examples of the ω-lactam used in the present invention include γ-butyrolactam, δ-valerolactam, ε-caprolactam, ω-enantholactam, ω-capryllactam, ω-undecanolactam, and ω-laurinlactam. Can be mentioned.
These omega-lactams may be used alone,
Two or more types may be used in combination. As the polymerization catalyst contained in component system (A), any compound used in the known anionic polymerization of ω-lactams can be used. Specific examples include alkali metals, alkaline earth metals, their hydrides, oxides, hydroxides, carbonates, alkyl compounds, aryl compounds, alkoxides, Grignard compounds, and ω- Reaction products with lactams, such as sodium salts, potassium salts of ω-lactams,
Examples include magnesium halide salt. The amount of polymerization catalyst used is 0.01 to 0.01 to total ω-lactam.
15, or 20 mol% or more. Regarding the polymerization promoter contained in component system (B),
Any compound known for use in anionic polymerization of ω-lactams can be used. Specific examples include isocyanates such as toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, polymethylene polyphenyl polyisocyanate, diisocyanate modified with carbodiimide, hexamethylene-1,6- Carbamide lactams such as biscarbamide, caprolactam, N,N'-diphenyl-P-phenylene biscarbamide caplactam, N,N'-diphenyl-P-phenylene biscarbamide, pyrrolidone, terephthaloyl chloride , acid halides such as adipic acid chloride and sebacic acid chloride,
Adipoyl biscaprolactam, adipoyl bispyrrolidone terephthaloyl biscaprolactam,
Polyacyllactams such as terephthaloyl bispyrrolidone or formula

【formula】

【formula】

【formula】

[Formula] and Beauty

[Formula] [In the formula, A is halogen Is there or

where Y is C ₃ -C ₁₁ alkylene, a is an integer of 1, 2 or 3, b is an integer of 2 or more,
R ₁ is an alkyl group, an aralkyl group, an alkyloxy group, an aryloxy group, a halogen group, or an aralkyloxy group, and R ₂ is a divalent or higher valent group selected from a hydrocarbon group and a hydrocarbon containing an ether bond. and Z is (1) a polyether having a minimum molecular weight of about 2000; (2) a polyether having a minimum molecular weight of about 2000;
(3) a hydrocarbon having a minimum molecular weight of 1000; or (3) a hydrocarbon having a minimum molecular weight of 1000. The component system (B) can contain a crosslinking agent, a modifying agent (soft segment), etc. that enter the polymer chain when reacting with the component system (A) in the mold. Examples of these compounds include compounds having a polyvalent hydroxyl group, mercapto group, amino group, or epoxy group. Examples of compounds having polyvalent hydroxyl groups include alkylene glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, tetramethylene glycol, propylene glycol, dipropylene glycol, hexylene glycol, 1,2-propanediol,
1,3-propanediol, 1,3-hexanediol, butylene glycol, 1,4-butanediol, dicyclopentadiene glycol, heptaethylene glycol and isopropylidene bis(P-phenyleneoxypropanol-2),
Polyols other than alkylene glycols, such as glycerol, pentaerythritol, 1, 2, 6
- hexanetriol and 1-trimethylolpropane, polymeric polyols such as polyethylene glycol, polypropylene glycol, polyoxypropylene diol, and triols,
Mention may be made of polytetramethylene glycol, castor oil, polybutadiene glycol, polyester glycol, poly(ε-caprolactone) diol and a number of compounds containing substituents other than hydroxy groups such as 2,4 dichlorobutylene glycol. Examples of compounds having a polyvalent mercapto group include hydroxyethylthioglycolate, ethylene glycol bis(thioglycolate), pentaerythritol tetrakis(thioglycolate), and thiodiglycol. Examples of the compounds include hexamethylene diamine, tolylene diamine, 2,4-diethyltolylene diamine, polyoxyethylene diamine, polyoxypropylene diamine and triamine, polyoxypropylene diamine, and copolymerized polyamides with amino terminal groups. Examples of compounds having polyvalent epoxy groups include resorcinol diglycidyl ether, diglycidyl ether of bisphenol A, vinylcyclohexane dioxide, butanediol diglycidyl ether, polyglycidyl ester of polycarboxylic acid, epoxidized polyolefin, and glycidyl. There are ether resins, epoxy novolac resins, etc. The component system (B) may further contain compounds that do not substantially inhibit the polymerization reaction, such as plasticizers, blowing agents, dyes and pigments, antioxidants, and internal mold release agents. Next, to describe the method for manufacturing polyamide resin molded articles according to the present invention, first, a polymerization catalyst is added to ω-lactam, and the temperature is heated to a temperature higher than the melting point of ω-lactam (for example, 70°C or higher when the ω-lactam is caprolactam). Heat to create a melt of component system (A). This melt of component system (A) is maintained at 100° C. or lower in order to inhibit the polymerization reaction itself. Similarly, component system
(B) also involves adding a polymerization co-catalyst, additives, etc. to ω-lactam, heating it above the melting point of ω-lactam, and making a molten product held at 140°C or lower. Next, to the above preparation component system, add the required amount of glass fibers specified in the present invention to the total amount of the two-component polyamide component only to either component system (A) or (B), or to the component system
Part of it is in (A) or (B), the rest is in component system (B) or
Mix evenly with (A) or component systems (A) and (B). The above distribution mixing of glass fibers is determined each time depending on the viscosity of the component system (A) or (B), the type of ω-lactam, etc. To produce a molded article from the polyamide molding composition prepared as above, the following procedure is followed. First, component system (A) and (B) molten slurry are rapidly mixed and injected or poured into a mold. The two components can be mixed, for example, by collision mixing in a device called a mixing head, or by stirring and mixing with a static mixer or dynamic mixer. The mixing ratio of component systems (A) and (B) can be changed depending on the use and properties of the molded product to be manufactured. The mixing ratio in this case is preferably in the range of 5/1 to 1/5 by volume. The mold temperature during molding is preferably maintained in the range of 100 to 200°C, preferably 120 to 160°C. In the mold, a chemical reaction occurs between the component system (A) and the component system (B), and within a short time after injection into the mold, within 4 minutes depending on the size of the molded product, in some cases. It hardens or solidifies within the 2-part ratio, completing the chemical reaction. After the chemical reaction is complete, the molded product is removed from the mold. "Effects of the Invention" The present invention has been described above, and has the following particularly remarkable effects, and its industrial utility value is extremely large. (1) When using the method of the present invention, glass fiber is blended into the raw material composition, but since glass fibers with specific physical properties are selected and used, the raw material composition has low viscosity and excellent fluidity. It is easy to handle and easily injected into a mold during molding. (2) The molded product obtained by the method of the present invention has excellent rigidity and heat resistance, and has an excellent surface gloss, without impairing the characteristics of a polyamide molded product. (3) The molded article obtained by the method of the present invention has less distortion due to the orientation of glass fibers and less anisotropy in mechanical properties. "Examples" Next, the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. The types of glass fibers used in the following examples are as listed in the table below, and measurements of glass fiber length distribution, viscosity measurement of component systems (A) and (B),
The appearance evaluation of the molded product and the measurement of the bending rigidity of the molded product were performed as follows. Glass fiber type:

【table】

【table】

[Table] Measurement of glass fiber length distribution: - Place the glass fiber on a glass slide, drop ethylene glycol onto it, disperse it in the ethylene glycol, press it with a cover glass, and place it between two pieces of glass. Set the gap to be approximately the same as the diameter of the glass fiber, take a photograph at 125x magnification using a polarizing microscope, measure the length distribution of 1000 fibers three times, and use the average value as the fiber length distribution. Measurement of viscosity of component systems (A) and (B): - Using a Bruckfield viscometer, place the sample in a 500cc beaker, shear rate 13sec ^-1 , 100℃
Measure the apparent viscosity. Appearance evaluation of molded products: - Mainly by visual observation, but in some cases, surface roughness meter (Model SE manufactured by Kosaka Laboratory)
3A). The display criteria for the results are:
There were four levels: ◎: best, ○: good, △: fair, and ×: poor. Measuring the bending rigidity of a molded product: - Cut a dry test piece from a flat molded product,
Measured according to ASTM D-790. Example 1 The following component system (A) and component system (B) were each
cc flasks and maintained at a temperature of 100°C. Component system (A) ε-caprolactam 986gr Sodium pyrrolidone 14gr Milled glass A 330gr Component system (B) ε-caprolactam 538gr Terephthaloylpiscaprolactam 77gr Polypropylene glycol (MW=2000)
385gr Milled Glass A 333gr Samples were taken from each of the component systems (A) and (B), and the apparent viscosity was measured. The results are shown in Table 1. Next, take 100g each of component systems (A) and (B) into a beaker, mix with a propeller type stirrer, and immediately pour the mixture into a 300mm long, 200mm wide, deep, temperature-controlled area at 140°C with an electric heater. It was poured into a sheet mold with a cavity of 3 mm and held for 4 minutes. Table 1 shows the results of measuring the physical properties of the molded product obtained. Comparative Example 1 In the example described in Example 1, component systems (A) and (B) were prepared in the same manner as in the same example except that milled glass B was used instead of milled glass A as the glass fiber.
were prepared, and the apparent viscosity of each was measured, and a molded article was obtained in the same manner as in Example 1, and its physical properties were measured. The results are shown in Table 1. Comparative Example 2 In the example described in Example 1, the component system (A),
(B) was prepared, the apparent viscosity of each was measured, a molded article was obtained in the same manner as in Example 1, and its physical properties were measured. The results are shown in Table 1. Example 2 The following component system (A) and component system (B) were each
cc flasks and each was maintained at a temperature of 100°C. Component system (A) ε-caprolactam 802gr Bromomagnesium caprolactam 48gr Milled glass D 150gr Component system (B) ε-caprolactam 470gr Polymerization cocatalyst (A) 380gr Milled glass D 150gr Polymerization cocatalyst added to component system (B) A) is the following formula (However, in the formula, Z represents a block copolymer of ethylene oxide and propylene oxide having a molecular weight of about 6,000.) Samples were taken from each of the component systems (A) and (B), and the apparent viscosity was measured. The results are shown in Table 1. Next, 100g each of component systems (A) and (B) were placed in a beaker and a molded product was obtained in the same manner as in Example 1.
Its physical properties were measured. The results are shown in Table 1. Example 3 In the example described in Example 2, component systems (A) and (B) were prepared in the same manner as in the same example, except that milled glass F was used instead of milled glass D as the glass fiber.
were prepared, and the apparent viscosity of each was measured, and a molded article was obtained in the same manner as in Example 2, and its physical properties were measured. The results are shown in Table 1. Example 4 In the example described in Example 2, except that milled glass G was used as the glass fiber, component systems (A) and (B) were prepared in the same manner as in the same example, and the apparent viscosity of each was In addition, a molded article was obtained by the same method as in Example 2, and its physical properties were measured. The results are shown in Table 1. Comparative Example 3 In the example described in Example 2, component systems (A) and (B) were prepared in the same manner as in the same example, except that milled glass E was used instead of milled glass D as the glass fiber.
were prepared, and the apparent viscosity of each was measured.A molded article was obtained in the same manner as in Example 2, and its physical properties were measured. The results are shown in Table 1. Comparative Example 4 In the example described in Example 2, the component system was changed in the same manner as in the same example except that milled glass H was used instead of milled glass D as the glass fiber.
(A) and (B) were prepared, the apparent viscosity of each was measured, and a molded article was obtained in the same manner as in Example 2, and its physical properties were measured. The results are shown in Table 1. Example 5 In the example described in Example 2, the component system was prepared in the same manner as in the same example, except that milled glass I was used instead of milled glass D as the glass fiber.
(A) and (B) were prepared, the apparent viscosity of each was measured, and a molded article was obtained in the same manner as in Example 2, and its physical properties were measured. The results are shown in Table 1. Comparative Example 5 In the example described in Example 5, component systems (A) and (B) were prepared in the same manner as in the same example except that milled glass J was used instead of milled glass I as the glass fiber.
were prepared, and the apparent viscosity of each was measured, and a molded article was obtained in the same manner as in Example 5, and its physical properties were measured. The results are shown in Table 1. Comparative Example 6 In the example described in Example 5, the component system was changed in the same manner as in the same example except that milled glass K was used instead of milled glass I as the glass fiber.
Prepare (A) and (B), measure the apparent viscosity of each,
In addition, a molded product was obtained by the same method as in Example 4,
Its physical properties were measured. The results are shown in Table 1. Example 6 In the example described in Example 5, the component system was changed in the same manner as in the same example except that milled glass L was used instead of milled glass I as the glass fiber.
(A) and (B) were prepared, the apparent viscosity of each was measured, and a molded article was obtained in the same manner as in Example 5, and its physical properties were measured. The results are shown in Table 1. Comparative Examples 7 and 8 In the example described in Example 6, the component system (A ), prepare (B),
The apparent viscosity of each was measured, and molded products were obtained using the same method as in Example 6, and their physical properties were measured. The results are shown in Table 1. Example 7 The following component system (A) and component system (B) were each
cc flasks and each was kept at 100°C. Component system (A) ε-caprolactam 661gr Bromomagnesium caprolactam 39gr Milled glass D 300gr Component system (B) ε-caprolactam 388gr Polymerization cocatalyst (A) 312gr Milled glass D 300gr (Note) Polymerization cocatalyst (A) is based on the example The same one used in 2. Samples were taken from each of the component systems (A) and (B), and the apparent viscosity was measured. The results are shown in Table 1. Next, put 100g of each of component systems (A) and (B) into a beaker, mix with a propeller type stirrer, and proceed as follows.
A molded article was obtained by the same method as in Example 1, and its physical properties were measured. The results are shown in Table 1. Comparative Examples 9 and 10 In the example described in Example 7, the component system was changed in the same manner as in the same example, except that milled glass E (comparative example 9) or milled glass H (comparative example 10) was used as the glass fiber. Prepare (A) and component system (B),
The apparent viscosity of each was measured, and molded products were obtained using the same method as in Example 7, and their physical properties were measured. The results are shown in Table 1. Example 8 In the example described in Example 7, except that milled glass O was used, the same procedure as in the same example was carried out.
A component system (A) and a component system (B) were prepared, and the apparent viscosity of each was measured.A molded article was obtained in the same manner as in Example 7, and its physical properties were measured. The results are shown in Table 1. Example 9 In the example described in Example 7, component systems (A) and (B) were prepared in the same manner as in the same example, except that milled glass Q was used as the glass fiber, and the apparent viscosity of each was determined. Furthermore, a molded article was obtained in the same manner as in Example 7, and its physical properties were measured. The results are shown in Table 1. Comparative Example 11 In the example described in Example 8, the component system was changed in the same manner as in the same example, except that milled glass P was used instead of milled glass O as the glass fiber.
(A) and (B) were prepared, and the apparent viscosity of each was measured. Also, a molded article was obtained in the same manner as in Example 8, and its physical properties were measured. The results are shown in Table 1. Comparative Example 12 In the example described in Example 9, the component system was changed in the same manner as in the same example, except that milled glass R was used instead of milled glass Q as the glass fiber.
(A) and (B) were prepared, the apparent viscosity of each was measured, and a molded product was obtained by the same method as in Example 9,
Its physical properties were measured. The results are shown in Table 1. Example 10 The following component system (A) and component system (B) were each prepared in a raw material tank of a reaction injection molding machine, and each was maintained at 100°C. Component system (A) ε-caprolactam 33.0Kg Bromomagnesium caprolactam 2.0Kg Component system (B) ε-caprolactam 19.4Kg Polymerization cocatalyst (B) 15.6Kg Milled glass A 30.0Kg Polymerization cocatalyst added to component system (B) (B) is the following formula (However, Z represents polybutadiene with a molecular weight of about 6000.) A sample was taken from component system (B) and its apparent viscosity was measured. The results are shown in Table 1. Next, component systems (A) and (B) were mixed by collision using a reaction injection molding machine, and injected into a sheet mold having a cavity of 500 mm in length and width and 3 mm in depth, temperature controlled at 140°C. The molded product was held for 2 minutes and its physical properties were measured. The results are shown in Table 1. Comparative Examples 13 and 14 In the example described in Example 10, milled glass B was used instead of milled glass A as the glass fiber.
(Comparative Example 13) and Milled Glass C (Comparative Example 14) were used. Component systems (A) and (B) were prepared in the same manner as in Example 10, respectively, and each component system (B )
The apparent viscosity was measured, and molded products were obtained using the same method as described in Example 10, and their physical properties were measured. The results are shown in Table 1.

[Table] From the results in Table 1, the following is clear. (1) The polyamide cast composition prepared by the method of the present invention has a viscosity on average compared to a comparative example (a composition containing glass fiber whose physical properties are outside the range specified by the present invention). small. This shows that ease of handling and injection fluidity into the mold are superior. (2) The polyamide resin molded product obtained by the method of the present invention has an excellent appearance compared to the molded product obtained by the method of the comparative example, and the characteristics of the polyamide molded product are not impaired. Furthermore, the bending rigidity of the molded product was comparable to that of the comparative example, indicating that the glass fibers functioned satisfactorily as a reinforcing material.

Claims (1)

[Scope of Claims] 1. In producing a polyamide resin molded article, fibers are added to either or both of the ω-lactam melt containing a polymerization catalyst and the ω-lactam melt containing a polymerization co-catalyst. Less than 3% by weight is less than 25μm in length, 30% by weight is more than 300μm
or less, and the weight average fiber length is 75 μm or more
A method for producing a polyamide resin molded article, which comprises blending glass fibers with a diameter of 125 μm and injecting or injecting the mixture into a mold to form a molded article. 2. Claim 1, wherein the glass fiber has a diameter in the range of 5 μm to 25 μm.
A method for producing a polyamide resin molded product as described in Section 1. 3 The amount of glass fiber blended is the total amount of the raw material composition.
Claim 1 or 2, characterized in that the amount is in the range of 1 to 50 parts by weight per 100 parts by weight.
A method for producing a polyamide resin molded product as described in Section 1. 4. The method according to claim 1, 2, or 3, characterized in that a crosslinking agent or a reaction product modifier is blended into the omega-lactam melt containing the polymerization cocatalyst. A method for manufacturing polyamide resin molded products.