JPH02150449A - Molding material - Google Patents

Abstract

PURPOSE:To provide a molding material having excellent mechanical properties such as breakage torque and tensile strength and suitable for fine shapes such as gears by compounding a polyamide resin with a mixture of long fiber type glass fibers and short fiber type glass fibers. CONSTITUTION:100 pts.wt. of a polyamide is compounded with 50-250 pts.wt. of a mixture of long fiber type glass fibers having fiber lengths of >=2mm and short fiber type glass fibers having an average fiber length of 0.1-1mm to provide a molding material, the glass fiber mixture comprising the long fiber type glass fibers and the short fiber type glass fibers in a ratio of 100 pts.wt./(10-100) pts.wt. The polyamide resin is preferably mixed polyamides comprising 40-99 pts.wt. of a polyamide resin prepared from xylylenediamine and an alpha,omega-straight chain aliphatic dibasic acid and 60-1 pts.wt. of nylon 66. Adipic acid is especially suitable among the alpha,omega-straight chain aliphatic dibasic acids.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a glass fiber reinforced polyamide resin molding material having excellent mechanical properties.

More specifically, the present invention provides excellent mechanical properties, even in molded products with fine shapes such as bolts and gears.
In particular, it relates to a polyamide resin molding material having excellent mechanical properties such as breaking torque and tensile strength.

[Prior Art] Polyamide resin generally has excellent mechanical properties as well as excellent thermal and chemical properties, so it is widely used as a molding material for electrical, electronic parts, machinery, precision parts, automobile parts, etc. ing.

Furthermore, glass fiber-reinforced polyamide resin has excellent mechanical properties, so it is being used in a wide range of fields as a substitute for metals.In particular, long-fiber type resins are used in fields that require high strength, high rigidity, and high impact resistance. glass fiber is used. However, in molded products with fine shapes such as bolts and gears, the long fiber type glass fibers are not sufficiently filled into the details, which deteriorates the mechanical properties of the molded product and poses a practical problem. ing.

[Problems to be Solved by the Invention] An object of the present invention is to overcome the deficiencies of the prior art as described above and to provide a molding material with high commercial value. In other words, an object of the present invention is to provide a polyamide resin molding material that has excellent mechanical properties even when molded into molded products with fine shapes such as bolts and gears. The goal is to provide the following.

[Means for Solving the Problems] As a result of extensive studies, the present inventors have developed a polyamide resin containing a mixture of long fiber type glass fibers with a fiber length of 2 mm or more and short fiber type glass fibers with an average fiber length of 0.1 to Irnm. The present inventors have discovered that when a molding material containing .

That is, the present invention uses long-fiber type glass fibers with a fiber length of 2 mm or more and an average fiber length of 0.5 mm based on 100 parts by weight of polyamide resin. A polyamide resin molding material containing 50 to 250 parts by weight of a glass fiber mixture consisting of short fiber type glass fibers of 1 to 1 mm, wherein the glass fiber mixture is composed of short fiber type glass fibers based on 100 parts by weight of the long fiber type glass fibers. This invention relates to a polyamide resin molding material characterized by containing 10 to 100 parts by weight of glass fiber.

Examples of the polyamide resin used in the present invention include polyamide resins obtained by polycondensation of lactams or ω-amino acids having four or more membered rings, or polycondensation of dibasic acids and diamines.

Examples of the lactam or ω-amino acid having four or more membered rings include ε-caprolactam, ω-laurolactam, ω-aminocaprylic acid, and ω-aminolauric acid.

Polyamides obtained from dibasic acids and diamines include geltaric acid, adipic acid, azelaic acid, sebacic acid,
Dibasic acids such as speric acid, dodecanniic acid, eicosionic acid, isophthalic acid, and terephthalic acid, and diamines such as tetramethylene diamine, hexamethylene diamine, octamethylene diamine, metaxylylene diamine, paraxylylene diamine, and paraphenylene diamine. Examples include polymers or copolymers obtained from

Specific examples of the polyamides include nylon 4, nylon 6, nylon 12, nylon 66, nylon 610, nylon 612, polymethaxylylene adipamide, polymethaxylylene adipamide, polymethaxylene dodecamide, polyhexamethylene Examples include, but are not limited to, phthalamide and mixtures or copolymers thereof.

In the present invention, among the polyamides exemplified above, when a metaxylylene group-containing polyamide resin (hereinafter referred to as rMX nylon) is used, a molded article having particularly excellent performance in terms of mechanical properties, water resistance, etc. can be obtained.

Among the above-mentioned MX nylons, metaxylylene diamine alone or a diamine mixture containing 60% by weight or more of metaxylylene diamine and 40% by weight or less of para-xylylene diamine and an α, ω-linear chain having 6 to 20 carbon atoms are preferable. Examples include polyamide resins synthesized by polycondensation reaction with aliphatic dibasic acids such as adipic acid, sebacic acid, sperinic acid, dodecanoic acid, and eicosionic acid.

Among the MX nylons, adipic acid is particularly preferred among the α,ω-linear aliphatic dibasic acids, considering the balance of moldability, molded product performance, and the like.

Furthermore, when Mx nylon is used as the polyamide resin, blending nylon 66 with the MX nylon has the effect of shortening the moldability of the MX nylon, that is, the cycle time during molding.

In this case, the blending ratio of nylon 66 to MX nylon is effective over a wide range in terms of shortening molding time, and the blending ratio is 40 to 99% for MX nylon.
Nylon 6660 to 1 part by weight, preferably 60 to 97 parts by weight of MX nylon to nylon 664
There are 0 to 3 overlapping parts.

When the blending ratio of nylon 66 is less than 1 part by weight based on 99 parts by weight of MX nylon, the effect of improving the moldability of MX nylon is small. Furthermore, if the blending ratio of MX nylon is less than 40 parts by weight based on 6660 parts by weight of nylon, it is not preferable because performance such as a decrease in mechanical strength or a decrease in physical properties due to water absorption occurs.

Chopped strands or milled fibers are used as short fiber type glass fibers in the present invention.

As will be described later, the short fiber type glass m-fiber is molded into a molding material (in the form of a pellet) by extruding it together with a polyamide resin and glass roving using an extruder.

At this time, the average fiber length of the short uJl type glass fibers in the molding material is 0.1 to 1, Qmm.

The average fiber length of short fiber type glass fibers in the molding material is 0.
．． If the average fiber length is 1 mm or less, the mechanical strength of the molded product will be insufficient, and if the average fiber length is 1.Q mm or more,
This is not preferable because the glass fibers are not properly filled into the finely shaped parts of the molded product, and the mechanical strength is insufficient in the finely shaped parts.

Ordinary glass roving can be used as the long fiber type glass fiber of the present invention.

The fiber length of the long fiber type glass fiber in the molding material (pellet form) of the present invention is 2 mm or more, preferably 2.5 m.
m or more, particularly preferably 3 mm or more.

The polyamide resin molding material of the present invention is produced using an extruder in which polyamide and chopped glass fibers, which are short fiber type glass fibers, are heated at a temperature 5 to 50°C higher than the melting point or flow start temperature of the polyamide. It is obtained by melt-kneading strands or milled fibers, impregnating the mixture into a glass roving to become long fiber type glass fibers using a die, and cutting the glass roving using a pelletizer. In this step, the molding material is cut into lengths of 2 mm or more using a pelletizer.

If the molding material is cut into lengths of 2 mm or less, the fiber length of the long fiber type glass fibers in the molding material will naturally be 2 mm or less, and in this case, the reinforcing effect in the molded product will be reduced, which is not preferable.

The short fiber type and long fiber type glass fibers used in the present invention preferably have an average fiber diameter of 5 to 15 μm, but the present invention is not limited to this fiber diameter.

The blending ratio of the mixture of long fiber type glass fiber and short fiber type glass fiber in the molding material of the present invention is 50 to 250 parts by weight per 100 parts by weight of the above polyamide resin,
Preferably it is 70 to 200 parts by weight. 50 parts by weight of the above glass fiber mixture per 100 parts by weight of polyamide resin.
If the amount is less than 250 parts by weight, the effect of improving the mechanical strength of the molded product will be small, while if the glass fiber mixture is more than 250 parts by weight, the fluidity will be poor during molding processing, causing practical problems.

In addition, in the present invention, the blending ratio of long fiber type glass fiber and short fiber type glass fiber is 100 parts by weight of long fiber type glass fiber to 1 part by weight of short fiber type glass fiber.
It is 0 to 100 parts by weight.

If the blending amount of short fiber type glass fiber is less than 10 parts by weight per 100 parts by weight of long fiber type glass fiber, the filling of the glass fiber into the finely shaped parts of the molded product will be insufficient and the mechanical strength will be low. On the other hand, if the amount of short fiber type glass fiber added is 100 parts by weight or more, the effect of improving the mechanical strength of the molded article is small.

The glass fiber used in the present invention may be surface-untreated or may be surface-treated with a coupling agent such as a silane coupling agent or a titanate coupling agent. Those treated with a coupling agent are preferred.

The polyamide resin molding material of the present invention further contains additives, such as stabilizers against deterioration due to oxidation, heat, ultraviolet light, etc.
A nucleating agent, a lubricating agent, a mold release agent, an antistatic agent, a lubricant, a pigment, etc. can be blended as appropriate.

In addition, inorganic fillers such as calcium carbonate, talc, and wollastonite, potassium titanate, silicon carbide whiskers, carbon fibers, ceramic fibers, and carbon fibers may be added to the polyamide resin composition of the present invention within a range that does not impair the purpose of the present invention. Pigments such as black may also be appropriately blended.

[Effects of the Invention] The polyamide resin molding material of the present invention provides a molded product with particularly excellent mechanical properties, and eliminates the fine shape that is a drawback of conventional polyamide resins reinforced only with long fiber type glass fibers. It is extremely useful as a metal substitute material because it eliminates the decrease in strength of molded products.

[Example] Next, the present invention will be specifically described with reference to Examples and Comparative Examples. The method of filling glass fiber into the details of a molded article having a fine shape and evaluating the mechanical properties of the present invention was by measuring the breaking torque and tensile strength of the bolt molded article as described below.

The bolt was molded using M6 coarse hexagonal bolt (based on JISB1180) by injection molding.

The breaking torque was measured using a Karan idle-rotating torque screwdriver.

The tensile strength was measured by attaching an M6 nut to the bolt and pulling it in axially symmetrical directions (at a pulling speed of 5 mm/min), and taking the strength at which the bolt breaks at this time as the tensile strength.

Example 1 Poly (methaxylylene adipamide) (Mitsubishi Gas Chemical ■
1 g of the polymer was dissolved in 100 ml of 98% sulfuric acid,
Relative viscosity measured at °C (JIS-6810 (1
977)). (hereinafter referred to as "relative viscosity"): 2.14) 90 parts by weight and nylon 66
(relative viscosity: 2.25) pellets 10 parts by weight, length 3
14.3 parts by weight of glass fiber chopped strands of 2.5 mm in diameter were mixed in a tumbler, and 2.7 mm in weight were mixed using a vented extruder.
Polyamide resin 100 is extruded after melt-kneading at 5°C.
The glass roving was impregnated in an amount of 28.6 parts by weight, and then cut into a length of 4 mm to produce a pellet-shaped molding material. Long fiber type glass Il obtained by cutting glass roving! The fiber length was 4 mm, which was equal to the pellet length. Further, the chopped glass fiber strands having a length of 3 mrn were crushed in the extruder and had an average fiber length of 0.26 mm. This molding material was injection molded at a mold temperature of 130° C. to obtain an M6 bolt molded product. The performance test results of the molded products are shown in Table 1.

Example 2 In Example 1, poly(methaxylylene adipamide) 8
A pellet-shaped molding material having a length of 3.5 mm was obtained using 0 parts by weight of 6620 parts by weight of nylon, 40 parts by weight of chopped glass fiber strands having a length of 3 mm, and 60 parts by weight of glass roving IB. Using this, a molded product was obtained in the same manner as in Example 1. The test results of this molded product are shown in Table 1.

Example 3 A molded article was obtained in the same manner as in Example 1, except that 50 parts by weight of chopped glass fiber strands having a length of 3 mm and 100 parts by weight of glass roving were used. The test results of this molded product are shown in Table 1.

Example 4 Nylon 66100 was used as the polyamide resin of Example 2.
A molded product was obtained in the same manner as in Example 2 except that parts by weight were used. The test results of this molded product are shown in Table 1.

Comparative Example 1 Chopped glass fiber strand with a length of 3 mm 28.6
A molded article was obtained in the same manner as in Example 1 except that 143 parts by weight of glass roving were used. The test results for this molded product are shown in Table 2. The breaking torque of the bolt and the tensile strength of the bolt were low and insufficient.

Comparative Example 2 A molded product was obtained in the same manner as in Example 2, except that in Example 1, the chopped glass fiber strands were not used and 150 parts by weight of glass roving was used. The test results for this molded product are shown in Table 2.

The breaking torque of the bolt and the tensile strength of the bolt were low and insufficient.

Comparative Example 3 In Example 1, glass fiber chopped strand 1
Molding was attempted in the same manner as in Example 1 except that 170 parts by weight of the glass roving and 170 parts by weight of the glass roving were used.

However, due to the large amount of glass fiber blended, the fluidity during molding was poor and molding was impossible.

Comparative Example 4 Nylon 66100 was used as the polyamide resin of Example 1.
A molded product was obtained in the same manner as in Example 4 except that 100 parts by weight of glass roving was used, without using chopped strands as the glass fiber. The test results of this molded product are shown in Table 2. The breaking torque of the bolt and the tensile strength of the bolt were low and insufficient.

*The blending ratio of the composition is shown in parts by weight.

Patent applicant: Mitsubishi Gas Chemical Co., Ltd. Agent: Patent Attorney Sadafumi Kohori

Claims (2)

[Claims] (1) Fiber length: 2 m for 100 parts by weight of polyamide resin
long fiber type glass fiber with an average fiber length of 0.
A polyamide resin molding material containing 50 to 250 parts by weight of a glass fiber mixture consisting of short fiber type glass fibers of 1 to 1 mm, wherein the glass fiber mixture is composed of short fiber type glass fibers based on 100 parts by weight of the long fiber type glass fibers. A polyamide resin molding material containing 10 to 100 parts by weight of glass fiber. (2) Polyamide resin and xylylene diamine α, ω
- Polyamide resin obtained from linear aliphatic dibasic acid 4
Claim No. 1, which is a mixed polyamide resin consisting of 0 to 99 parts by weight and 60 to 1 part by weight of nylon 66.
The polyamide resin molding material described in .