JPH0822947B2 - Polyamide resin molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a glass fiber reinforced resin composition,
More specifically, glass fibers having an average length of 0.5 mm or more are blended in a specific ratio, and the glass fiber length in the molded articles obtained from these compositions is in the range of 0.05 to 0.6 mm on average. Heat resistance, chemical resistance, mechanical properties, electrical properties as well as molding shrinkage, dimensional changes in water absorption, dimensional stability such as warpage deformation, and glass fiber reinforced polyamide resin compositions with excellent molding appearance. is there.

b. Conventional technology Polytetramethylene adipamide resin (Nylon 46
Has excellent heat resistance, toughness, chemical resistance, and sliding characteristics, and is expected to be put to practical use as a structural material in various applications.

However, the glass fiber reinforced resin of nylon 46 has a mechanical strength depending on the fiber length of the glass fiber contained in the resin,
It has been clarified that heat resistance, impact resistance, dimensional stability, molding appearance, etc. are affected.

Generally, a method of adding inorganic powder fillers such as calcium carbonate, titanium oxide, magnesium carbonate, silicic acid, and clay is often used as a method for improving these performances. Therefore, a method for simultaneously improving the rigidity, heat resistance and dimensional stability while maintaining the impact resistance and molding appearance of nylon 46 has not been found yet.

c. Problems to be Solved by the Invention The present inventors have conducted extensive studies to improve the above problems of nylon 46. As a result, nylon 46 is mixed with a specific glass fiber, and a molded article obtained from these compositions is obtained. The present invention has been found to have an excellent balance of physical properties such as rigidity, heat resistance, dimensional stability, impact resistance and molding appearance by controlling the glass fiber length within a specific range.

d. Means for Solving the Problems The present invention is obtained by molding a composition in which 20 to 90% by weight of polytetramethylene adipamide and 10 to 80% by weight of glass fiber having an average fiber length of 1 to 20 mm are mixed. Provided is a polyamide resin molded product, characterized in that the glass fiber length in the molded product is 0.05 to 0.6 mm on average and the standard deviation of the glass fiber length is 0.1 to 0.5 mm. It is a thing.

Nylon 46 used in the present invention is a polyamide consisting essentially of the following formula _{[NH- (CH 2) 4 -NH-} CO- (CH 2) 4 -CO ] repeating structural unit represented by. The manufacturing method thereof is described in, for example, JP-A-56-1494.
No. 30, No. 56-149431, No. 58-83029, JP-A No. 60-288
The method described in No. 43 etc. can be mentioned.

Further, in order to obtain the resin composition according to the present invention, a relative viscosity of 1.5 or more, preferably 2.5 to 5.0 (ηre 1: 30 ° C. 97% sulfuric acid 10%
Nylon 46 with (measured in a solution of 1 g of polymer in 0 ml)
It is advantageous to use The use role of nylon 46 in the composition of the present invention is 20 to 90% by weight, preferably 35 to 85% by weight.
% By weight.

If it is less than 20% by weight, the molding processability and the molding appearance are remarkably deteriorated, while if it exceeds 90% by weight, the impact resistance, rigidity, heat resistance and dimensional stability are not sufficiently improved, which is not preferable.

The glass fiber applied to the present invention is a glass chopped strand made of a continuous long fiber strand having a diameter of about 3 to 20 μm among the glass fibers generally used as a reinforcing agent for thermoplastic resins and thermosetting resins. Usually, the average length is 1 to 20 mm, preferably 2 to 10 mm.

The composition and manufacturing method of the glass fiber used in the present invention are not particularly limited as long as they have the above-mentioned shape, but preferably those treated with an aliphatic surface treatment agent are pelletized. The problem of pellet coloration due to the occasional heat deterioration is improved, and a much better quality product is obtained.

The average length of the glass fiber used in the present invention is 1 m.
If the length is shorter than m, the impact resistance, heat resistance, rigidity and dimensional stability of nylon 46 are not sufficiently improved, which is not preferable.

In the polyamide resin composition of the present invention, the glass fiber is used in an amount of 10 to 80% by weight, preferably 15 to 60% by weight, more preferably 15 to 50% by weight. If the content of the glass fiber is less than 10% by weight, the effect of improving impact resistance, heat resistance, rigidity and dimensional stability is small, and if it exceeds 80% by weight, the molding processability and the molding appearance are deteriorated.

The molded article of the present invention is a molded article obtained by adjusting various injection molding conditions using these compositions,
The average glass fiber length in the molded product is 0.05 to 0.6 mm, preferably 0.1 to 0.4 mm. Also, the standard deviation is 0.1
.About.0.5 mm, preferably 0.1 to 0.3 mm.

The ratio of the length / diameter of the glass fiber in the molded product (aspect ground) is preferably 3 to 50, more preferably 5 to 40,
Particularly preferably, it is 10 to 30.

If the glass fiber length in the molded product is shorter than 0.05 mm on average, the impact resistance, rigidity and dimensional stability of nylon 46 are not sufficiently improved, which is not preferable. If it is 0.6 mm or more, the molding appearance will be deteriorated.

Further, if the standard deviation of the glass fiber length in the molded product is smaller than 0.1 mm, the physical properties of impact resistance, rigidity, heat resistance, dimensional stability and the like and the surface appearance of the molded product are unbalanced, which is not preferable. Further, even when the thickness exceeds 0.5 mm, it is difficult to obtain a desired molded product because the above-mentioned physical property balance is lost.

As a method for adjusting the dimensions of the glass fiber in the molded article within the scope of the present invention, the purpose is to appropriately adjust the injection speed during molding, the rotation of the screw, the molding conditions of the molding temperature, the gate size of the molding die, etc. The dimensions can be

In the polyamide resin composition used in the present invention, if necessary, other additives such as stabilizers, lubricants, fillers, foaming agents and foaming aids, antistatic agents, flame retardants, and colorants may be used. Be free. Further, fillers such as carbon fiber, various whiskers, mica, talc and calcium carbonate can be appropriately added and used. By blending these fillers, physical properties such as sink marks and warpage can be improved.

If necessary, the following polymer components may be contained. For example, polybutadiene, butadiene-styrene copolymer, acrylic rubber ethylene-propylene polymer, EPDM, styrene-butadiene block copolymer, styrene-butadiene-styrene block polymer, styrene-butadiene-styrene radial teleblock polymer, polypropylene, Butadiene-acrylonitrile copolymer, ABS resin, AES resin, polyvinyl chloride,
Polycarbonate, styrene-acrylonitrile copolymer, PET, PBT, polyacetal, apoxy resin, polyvinylidene fluoride, polysulfone, ethylene-vinyl acetate copolymer, polyisoprene, natural rubber, chlorinated butyl rubber, chlorinated polyethylene, PPS resin, Polyether,
Examples thereof include ether ketone, PPO resin, styrene-methyl methacrylate copolymer, and styrene-maleic anhydride copolymer. If desired, a polyamide other than nylon 46 may be used in combination with the resin composition of the present invention.

For example, nylon 6, nylon 66, nylon 6, 10,
Examples thereof include a copolymer of terephthalic acid and trimethylhexamethylenediamine, and a copolymer of xylylenediamine and an aliphatic carboxylic acid such as poly (meta-xylene adipamide).

Since the present invention has its excellent properties, it is used for automobile engine covers, silencer brake master cylinders, air ducts, various exteriors, connectors for VTRs, connectors such as optical fiber connectors, door handles, bearing retainers, chain tensioner brake levers, window frame heat insulation. We can provide molded products such as frames, magnet switches, radiator tanks, sprocket wheels, windsurfing parts and fishing tackle parts.

e. Examples Examples 1 to 3 show chopped strands (03-MA-FTZ manufactured by Asahi Fiber Glass Co., Ltd.) having an average length of 3 mm and nylon 46 made from strands of continuous long fibers having a diameter of about 13 μm. The mixture was mixed in a tumbler in the proportions shown in 1 at the same time, and then melt-mixed using an extruder at a cylinder temperature of 300 to 330 ° C. The mixture is molded by an injection molding machine under the following conditions,
A test piece was produced.

(Molding conditions) cylinder temperature of two hundred ninety to three hundred twenty ° C. Mold temperature 80 to 120 ° C. Injection pressure 100~800kg / cm ² Injection time 1~5sec cooling time 10~50sec screw rotation 50~250rpm gate sizes 0.5 × 2.0mm~1.7 × 3.8 mm Liner size 8 mm PS40E injection molding machine manufactured by Nissei Plastic Co., Ltd. The obtained test pieces were evaluated for each physical property by the following evaluation methods, and the results shown in Table 1 were obtained. From the results shown in Table-1, it was found that the molded article of the present invention had the physical properties aimed at by the present invention.

(Evaluation method) Deflection temperature under load (HDT): ASTM D648 Load 18.6km / cm ² No annealing Bending strength, flexural modulus: ASTM D790 Bending speed 15mm / min Izod impact strength: ASTM D256 23 ℃ Notch Molding shrinkage rate: Molding The dimensional change in the flow direction after 24 hours was measured.

Test piece 1/2 ″ × 1/8 ″ × 5 ″ Molding appearance: The appearance of a 1.6 mm-thick orientation plate was visually evaluated.

⊚: Glossy and smooth surface.

◯: The surface is slightly inferior in gloss and the surface is smooth.

Δ: There is no gloss and the surface is slightly rough.

X: There is no gloss and the surface is rough.

Glass fiber length during molding: A polymer solution dissolved in an m-cresol solution (5% concentration) was placed on a glass plate, air-dried with a solvent, and then photographed with an optical microscope to measure 150 to 200 glass fibers. The length was measured.

Comparative Examples 1 and 2 Using the glass fiber and nylon 46 used in Example 1, resin compositions were prepared in the composition ratios shown in Table-1, and the physical properties of Example 1 were evaluated in the same manner as in Example 1. The results are shown in Table-1.

Comparative Example 1 is a molded article that does not contain glass fibers and is out of the range of the present invention, and has insufficient heat resistance, rigidity, impact resistance, and dimensional stability. Comparative Example 2 uses a composition in which the amount of glass fiber exceeds the range of the present invention and is inferior in moldability and mold appearance.

Comparative Examples 3 and 4 A resin composition was prepared in the same composition ratio as in Example 3 using the glass fiber and nylon 46 used in Example 1, and molding conditions (gate size, injection speed screw rotation speed, molding temperature, etc.) ) Was changed to perform molding. These molded products (1 /
Evaluation was performed in the same manner as in Example 1 using 8 ″ × 1/5 ″ × 5 ″ UL bar. Side gate), and the results are shown in Table 1.

Comparative Examples 3 and 4 are molded products in which the glass fiber length in the molded product is outside the range of the present invention, and the physical properties such as rigidity, impact resistance, molding shrinkage and molding appearance are unfavorably poor.

Comparative Example 5 The molded product of Comparative Example 5 has the same composition ratio as that of Example 3, except that nylon 66 is replaced with nylon 66 (Amylan manufactured by Toray Industries, Inc.).
CM3006) was used, and the rigid, heat-resistant, impact-resistant, dimensionally stable, and molded appearance were inferior, and the desired physical properties were not obtained.

f. Effect of the Invention The polyamide resin composition of the present invention is a glass fiber having a specific glass fiber length blended with nylon 46 and molded under certain specific molding conditions to obtain a glass fiber having a specific glass fiber length. Within the range, it is possible to obtain a resin composition having a balance of rigidity, impact resistance, dimensional stability, heat resistance and physical properties of molding appearance.

Therefore, since the polyamide resin composition of the present invention has an excellent balance of physical properties, it provides molded products such as automobile exterior parts, interior parts, and various parts in the electric: electronic field that require high quality. The utility value of is extremely large.

 ─────────────────────────────────────────────────── --Continued from the front page Judgment panel for referees Chief referee Yoshio Narui Referee Referee Kane Toshito Referee Yoshihide Kawakami (56) References JP 61-188457 (JP, A) JP 61-278561 (JP, JP, A)

Claims (1)

[Claims] 1. A molded article obtained by molding a composition in which 20 to 90% by weight of polytetramethylene adipamide and 10 to 80% by weight of glass fiber having an average fiber length of 1 to 20 mm are mixed. A polyamide resin molded product, characterized in that the glass fiber length in the product is 0.05 to 0.6 mm on average and the standard deviation of the glass fiber length is 0.1 to 0.5 mm.