JPH039952A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To decrease the mold shrinkage factor (anisotropy) and to improve the appearance of a molded item by compounding a resin component consisting of a noncrystalline polyamide resin and another thermoplastic resin with an inorg. fiber consisting of a glass fiber and a ground mineral fiber. CONSTITUTION:A resin component (A) is obtd. by compounding 90-30wt.% (hereinbelow described as %) noncrystalline polyamide resin and 10-70% other thermoplastic resin, pref. a crystalline polyamide resin, a polyester resin or a vinyl (co)polymer. Separately, an inorg. fiber (B) is obtd. by compounding 90-10% glass fiber contg. pref. 50-70% SiO2, 2-15% Al2O3 and 10-20% CaO and having a mean fiber length of 1-10mm, a mean fiber diameter of 5-20mum and an aspect ratio of 50 or larger and 10-90% ground mineral fiber with a mean fiber length of 20-500mum and an aspect ratio of 5-100, pref. 10-60. 20-70% component A is compound with 80-30% component B.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a thermoplastic resin composition, which contains inorganic fiber as a reinforcing material, has high strength and high rigidity, and is moldable. The present invention relates to a thermoplastic resin composition that has a low shrinkage rate and anisotropy and provides a molded article with a good appearance.

[Conventional technology]

In recent years, there has been a trend toward lighter products in a wide range of fields such as automobiles, electrical/electronic equipment, and building materials.In particular, the physical properties of alternative materials for metal products such as mechanical parts and structural parts are increasing, with high strength and high rigidity. Not only that, but dimensional accuracy close to that of metal and good appearance of molded products are now required as important factors.

To meet these demands, glass fibers, carbon fibers, whiskers such as potassium titanate, powders such as talc and calcium carbonate, etc. are blended into thermoplastic resins either singly or in combination of two or more. . However, whiskers such as carbon fiber and potassium titanate are disadvantageous as materials for general-purpose industrial products because they are expensive materials, and powders such as talc and calcium carbonate are combined with glass fibers. Although the appearance of the molded product is good when used as a molded product, the improvement in strength by glass fiber tends to be hindered.Furthermore, when a large amount of glass fiber is used, the warp of the molded product increases significantly and the appearance deteriorates. was there.

Therefore, attempts have been made to overcome these problems by selecting resins. For example, non-crystalline polyamide resins have a higher water absorption rate than so-called aliphatic polyamide resins such as nylon 6 and nylon 6.6. The above-mentioned advantages include a low molding ratio, a small decrease in rigidity due to water absorption, a low molding shrinkage rate, less warping of molded products when reinforced with fibers, and excellent dimensional stability. It is widely used in engineering fields.

However, among such amorphous polyamide resins, those that provide good mechanical properties have extremely high molecular weights;
Its melt viscosity is high and moldability is poor. For this reason, attempts have been made to improve the molding processability, and for example, compositions made of amorphous polyamide resin and ABS resin (specially JP-A-63-170.459) and the like are known.

However, even in such resin compositions, when a large amount of inorganic fibers such as glass fibers are used, the appearance of the molded product deteriorates, and all of the above-mentioned problems have not been solved yet.

[Problem to be solved by the invention]

Therefore, as a result of intensive research to solve this problem, the present inventors used an amorphous polyamide resin as the matrix resin and a thermoplastic resin other than the amorphous polyamide resin, and added glass as a filler. By using a blend of fibers and crushed mineral fibers with an aspect ratio of 5 to 100 in a predetermined ratio, the strength can be improved compared to when only glass fibers are used.
As a result, it is possible to reduce the amount of relatively expensive glass fibers and non-crystalline polyamide resins used, as well as thermoplastic resins that cause less warping of molded products and maintain good appearance of molded products. It was discovered that a composition can be obtained, and the present invention was achieved.

Therefore, the object of the present invention is to provide high strength and high rigidity,
Moreover, it is an object of the present invention to provide a thermoplastic resin composition from which molded products with good dimensional accuracy and appearance can be obtained.

[Means for solving the problem]

That is, the present invention comprises 90 to 30% by weight of an amorphous polyamide resin and 10% by weight of a thermoplastic resin other than the amorphous polyamide resin.
-70% by weight of a resin component and 80-30% by weight of inorganic fibers, of which 90-10% by weight is glass fiber and the remaining 10-70% by weight. It is a thermoplastic resin composition in which 90% by weight is crushed mineral fiber with an aspect ratio of 5 to 100, and particularly preferably, the thermoplastic resin other than the above-mentioned amorphous polyamide resin is a crystalline polyamide resin, a polyester resin, or a vinyl-based resin. A thermoplastic resin composition using at least one resin selected from (co)polymers.

The present invention will be explained in detail below.

First, the amorphous polyamide resin used in the present invention is
Diamine components include ethylenediamine, hexamethylenediamine, p-aminocyclohexylmethane, m-xylenediamine, 1.4-bis(3-aminopropoxy)
One or more selected from cyclohexane, trans-hexahydro-p-phenylenediamine, etc. are used, and one or more selected from terephthalic acid, isophthalic acid, etc. are used as the aromatic dicarboxylic acid component. However, examples thereof include polymers and copolymers obtained by condensation reaction of these. Furthermore, α-pyrrolidone, ω-aminocaproic acid, ε-caprolactam, lauryllactam, aminododecanoic acid, 11-aminoundecanoic acid, para-aminobenzoic acid, 4-aminophenyl-4-
Aminocarboxylic acids such as carboxyphenyl ether,
It is also possible to copolymerize one or more aliphatic dicarboxylic acids such as adipic acid and sebacic acid. These polyamide resins may be used alone or in combination of two or more.

Further, the thermoplastic resin other than the amorphous polyamide resin used in the present invention may be any thermoplastic resin, but preferably one having a lower melt viscosity than the above-mentioned amorphous polyamide resin. Particularly preferred are crystalline polyamide resins, polyester resins, and vinyl (co)polymers.

First, as a crystalline polyamide resin, succinic acid, glutaric acid, adipic acid,
One or more types of superric acid, sebacic acid, bis(p-carboxyphenoxy)alkanes, etc., and ethylenediamine, hexamethylenediamine, p-aminocyclohexylmethane, m-xylenediamine, 4- One or more of bis(3-aminopropoxy)cyclohexane, transhexahydro-p-phenylenediamine, etc., and further, α-pyrrolidone, ω-aminocaproic acid, ε as an aminocarboxylic acid component.
- caprolactam, lauryllactam, aminododecanoic acid, 11-aminoundecanoic acid, paraaminobenzoic acid,
Examples include polymers and copolymers obtained by using one or more types of 4-aminophenyl-4-carboxyphenyl ether and the like and subjecting them to a condensation reaction. Specifically, there are nylon 6, nylon 6.6, nylon 12, etc.

Next, as a polyester resin, terephthalic acid, isophthalic acid, orthophthalic acid, dicarboxylic acid component,
, 6-naphthalene dicarboxylic acid, 1.5-naphthalene dicarboxylic acid, succinic acid, adipic acid, sebacic acid, 1,
Using 3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, etc. or esters thereof alone or in a mixture, and using ethylene glycol, propylene glycol, 4-butanediol, 1 as the diol component.
．． 2-butanediol, neopentyl glycol, 1,
5-bentanediol, 1,6-hexanediol, decamethylene glycol, cyclohexane dimetatool,
Examples include polymers obtained by condensation reaction of cyclohexanediol and the like alone or in combination. For example, polyethylene terephthalate (PE
T), polybutylene terephthalate (PBT), etc. can be suitably used.

Furthermore, vinyl-based (co)polymers include polyethylene,
Polymers such as hydrocarbon compounds such as polypropylene, or styrene-acrylonitrile copolymers, styrene-
Examples include styrenic (co)polymers such as acrylonitrile-butadiene copolymers.

These thermoplastic resins other than the amorphous polyamide resin can be used alone or in combination of two or more.

Next, the glass fibers used in the present invention are usually CaO,
The main components are Sin and A1!03, and C
aO in the range of 10 to 20% by weight, Sin, in the range of 50 to 7
Those containing Al2O2 in the range of 0% by weight and in the range of 2 to 15% by weight are preferred. This glass fiber is not particularly limited as long as it can be used as a reinforcing material for resin, and it may be either roving or chopped strand, and even if the surface is untreated, it may be made of borane or silane. Although the fiber surface may be treated with a compound, glass wool, which is made of short fibers and has a cotton-like appearance, is not preferable.

This glass fiber usually has an average fiber length of 1 to 1
0 cylinder, average fiber diameter is 5 to 20, preferably lθ to
154 and an aspect ratio L/D of 50 or more is used. These glass fibers may be cut when mixed with thermoplastic resin, and the average fiber length in the resin composition varies depending on the length of the glass fibers used and the mixing conditions, but the average fiber length is approximately the same as the original length. It may be about 20%, 0, 2-2 nm, preferably 0.3-1 m
It is m.

Mineral fibers that are mixed with the glass fibers in the matrix resin of amorphous polyamide resin and thermoplastic resin other than amorphous polyamide resin include rock wool,
Ceramic fiber Examples include silica fiber and alumina fiber.

Among these, rock wool is also called slag wool, mineral wool, etc., and usually contains 20 to 45% by weight of CaO and Si.
It contains 30 to 50% by weight of O□ and 5 to 20% by weight of AltOa, and also contains components such as MgO. Rock wool is usually made into fibers by melting natural stones such as basalt, andesite, and diabase, and blast furnace slag, which is a by-product during iron manufacturing, and the fiber length is several mm to several cm. The particle content is about 30 to 40%.

Such mineral fibers are crushed to have an average fiber length of 20~
500, preferably 50 to 200, and the aspect ratio L/D to 5 to 100, preferably 10 to 60. Crushing mineral fibers means cutting or crushing the mineral fibers, and can be crushed using a rotating disc type crusher, a compression crusher, an opposed roll type crusher, or the like. As the crushing method, a grinding method is preferable. The crushed mineral fiber used in the present invention is particularly preferably one that has been crushed using a crusher such as the one described above and then classified into fibers and particle bones using an air classifier or the like.

As in the case of glass fibers, the crushed mineral fibers may be cut when mixed with the thermoplastic resin, but the degree of cutting is relatively small because they are previously crushed.

In short, the fiber length and aspect ratio of the crushed mineral fibers contained in the resin composition are important, and it is preferable that the fiber length has relatively little variation. Such crushed mineral fibers, such as ground rock wool, have an average fiber length of 20 to 500/J.
In, preferably 70% or more of 100-200/J
1n, the average fiber diameter is 2 to 10/.1 m, preferably 70% or more thereof is 3 to 5 IjIn, and the aspect ratio L/D is 5 to 100.

In the present invention, the blending ratio of the amorphous polyamide resin and the thermoplastic resin other than the amorphous polyamide resin is 90 to 30% by weight of the amorphous polyamide resin and 10% by weight of the thermoplastic resin other than the amorphous polyamide resin. ~70% by weight. If the amount of the thermoplastic resin other than the amorphous polyamide resin is less than 10% by weight, the effect of improving moldability will be insufficient, and if it is more than 70% by weight, the strength will be significantly reduced.

The mixing ratio of the resin component and inorganic fiber is 20 to 70% by weight of the resin component and 80 to 30% by weight of the inorganic fiber. If the proportion of inorganic fibers exceeds 80% by weight, the strength will decrease, and if it is less than 30% by weight, the reinforcing effect will be insufficient.

As the inorganic fiber, a combination of glass fiber and crushed mineral fiber is used. In this case, 90% by weight of glass fiber
If it is blended at a high blending ratio exceeding , even though the objective of high strength can be achieved, the warpage of the molded product becomes large and the appearance deteriorates, which is not preferable. In addition, 90% crushed mineral fiber
If it is added in excess of % by weight, the strength will be insufficient. From these points, the proportion between glass fibers and crushed mineral fibers is 90-10% by weight, preferably 80-20% by weight of glass fibers, and 10-90% by weight of crushed mineral fibers.
Preferably it is 20 to 80% by weight.

Preparation of a resin composition consisting of an amorphous polyamide resin containing glass fibers and crushed mineral fibers and a thermoplastic resin other than the amorphous polyamide resin is performed by mixing each resin component and inorganic fibers within the above-mentioned mixing ratios. It is made by blending and uniformly mixing by a conventional method using an appropriate blender or the like.

In addition, the resin composition prepared in this way, which uses an amorphous polyamide resin and a thermoplastic resin other than the amorphous polyamide resin as a matrix resin, and contains glass fibers and crushed mineral fibers, can be produced by ordinary extrusion molding or It is molded into the desired product by injection molding or the like.

Note that the surfaces of the glass fibers and crushed mineral fibers may be treated with a treatment agent that improves adhesion to the resin component. In addition, when preparing the composition, flame retardants, colorants, and
plasticizer, stabilizer, antioxidant, ultraviolet absorber, crosslinking agent,
Dispersants, other additives, modifiers such as unsaturated carboxylic acid copolymers, inorganic fillers, other reinforcing fibers, etc. may be added.

〔Example〕

The present invention will be specifically described below based on Examples and Comparative Examples.

Examples 1 and 2 Amorphous polyamide resin (manufactured by Mitsubishi Kasei ■, part name Nipper Mid X21) and nylon 6, a thermoplastic resin other than amorphous polyamide resin (manufactured by Ube Industries (II), part name:
UBB nylon IIFB) is used as a matrix, and glass fiber (Nippon Sheet Glass) is added to this matrix in the proportions shown in Table 1.
manufactured by Nippon Steel Chemical Co., Ltd., average fiber length 3 mm, average fiber diameter 1311rn, aspect ratio 230) and crushed rock wool (prepared by Nippon Steel Chemical Co., Ltd. Product name: S-Fiber FF, average fiber length 120/-IIn, average fiber A pellet was prepared by kneading particles (with a diameter of 4 lines, an aspect ratio of 30, and a particle content of 1% or less) using an extruder.

This pellet was molded into a test piece by injection molding, and the test piece had tensile strength (ASTM D 639), bending strength (ASTM D 790), and notched 1/4''.
Izod impact strength (ASTM D 256) was measured. In addition, the above pellets can be injection molded to form side gates (
12wx2mm) l 60mmX 160+n
The warpage of the molded product is evaluated by molding a flat plate of 2 mm x 2 mm, measuring the warpage of the molded product after 24 hours, and expressing the degree of warpage in percentage (%). Evaluated using a three-level evaluation system: ：fair and ×：poor.
Furthermore, as a comprehensive evaluation, ◎: Great support, ○: Excellent, △:
A four-level evaluation was performed: normal and ×: problematic. The results are shown in Table 1.

Comparative Examples 1 to 3 Nylon 6 was used as a thermoplastic resin other than amorphous polyamide resin, and only glass fiber was blended as a filler, and talc (manufactured by Hayashi Kasei ■, average particle size 2.5M)
and glass fiber.
A resin composition was prepared in the same manner as in Example 1 by blending the resin compositions in the proportions shown in the table, and a test piece was molded to measure its physical properties and to evaluate its warpage and appearance. The results are shown in Table 1.

Table 1 Examples 3 and 4 A resin composition was prepared in the same manner as in Example 1, except that polybutylene terephthalate resin (PBT) was used as the thermoplastic resin other than the amorphous polyamide resin, and a test piece was molded. The physical properties were measured and the warpage and appearance were evaluated. The results are shown in Table 2.

Comparative Examples 4 to 6 PB as thermoplastic resin other than amorphous polyamide resin
Using T resin, resin components and inorganic fibers were blended in the proportions shown in Table 2, a resin composition was prepared in the same manner as in Example 3, and test pieces were molded and evaluated. The results are shown in Table 2.

Examples 5 and 6 AB as thermoplastic resin other than amorphous polyamide resin
A resin composition was prepared in the same manner as in Example 1, except that S resin was used, and a test piece was molded to measure its physical properties and evaluate its warpage and appearance. The results are shown in Table 3.

Comparative Examples 7 to 9 AB as thermoplastic resin other than amorphous polyamide resin
Using S resin, resin components and inorganic fibers were blended in the proportions shown in Table 3, a resin composition was prepared in the same manner as in Example 5, and test pieces were molded and evaluated. The results are shown in Table 3.

〔Effect of the invention〕

According to the present invention, it is possible to obtain a thermoplastic resin composition that can produce molded products that have high strength and high rigidity and also have good dimensional accuracy and appearance, which greatly contributes to the development of industry. It is a big thing.

Claims (2)

[Claims] (1) 20-70% by weight of a resin component consisting of 90-30% by weight of an amorphous polyamide resin and 10-70% by weight of a thermoplastic resin other than the amorphous polyamide resin, and 8 inorganic fibers.
0 to 30% by weight, and 90 to 10% by weight of the above inorganic fibers is glass fiber, and the remaining 1% by weight is glass fiber.
A thermoplastic resin composition characterized in that 0 to 90% by weight is crushed mineral fibers having an aspect ratio of 5 to 100. (2) Thermoplastic resin other than amorphous polyamide resin,
The thermoplastic resin composition according to claim 1, which is at least one resin selected from crystalline polyamide resins, polyester resins, and vinyl (co)polymers.