JPH08259808A - Polyamide-resin made vibration-fused hollow formed article - Google Patents

Abstract

PURPOSE: To obtain the subject article having little trouble of warpage, free from lowering of fusing strength and excellent in appearance by performing the primary forming of a polyamide resin composition consisting of a polyamide resin, glass fibers having non-circular cross sections and tabular fillers, and subjecting the formed plural hollow-body parts to vibration fusion. CONSTITUTION: A polyamide resin composition is composed of (A) 50-80wt.% of a polyamide resin (preferably, 6-nylon) having a relative viscosity of 2.5-4.0, (B) 20-50wt.%, preferably 30-45wt.% of non-circular glass fibers, whose cross section formed by cutting in the perpendicular direction against the longitudinal direction has a ratio of the major diameter to the mirror diameter of 1.3-10, preferably 1.7-4.5 and (C) 0-30wt.%, preferably 0-15wt.% of flaky fillers, in which the total amount of the components B and C is 20-50wt.%. Plural hollow- body parts are formed by the primary forming by using the polyamide resin composition and they are fused to each other by the vibration fusion of an amplitude of 0.5-2.0mm with sealing pressure of 5-100kg.cm<2> to obtain the objective hollow article.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow body molded article made of polyamide resin in which a plurality of hollow body parts are molded by primary molding and joined by vibration welding.

[0002]

2. Description of the Related Art In recent years, the use of plastic has expanded,
Taking advantage of these characteristics, it has been attempted to resinize an intake manifold of an automobile engine, for example, by vibration welding. As the material, a polyamide resin such as glass fiber reinforced 66 nylon or 6 nylon is mainly used, but a large amount of warpage often causes problems in assembling. It is known that plate-like fillers such as glass flakes and mica are effective for reducing warpage, for example, as disclosed in JP-A-53-121843, but the addition of the filler has been found to lower the welding strength. In the intake manifold application, the decrease in the welding strength may lead to a rupture when the internal pressure increases due to engine backfire or the like. It has also been proposed, for example, by Japanese Patent Laid-Open No. 2-173047 to blend glass fibers having a non-circular cross-section with polyester, polycarbonate and polyacetal resins in order to improve warpage without impairing mechanical strength. However, these also have not yet been a sufficient solution because polyester has hydrolysis resistance, polycarbonate has poor chemical resistance and oil resistance, and polyacetal has a low melting point.

[0003]

Therefore, there has been a demand for a solution capable of improving warpage without lowering the welding strength and obtaining a vibration welded molded product made of a polyamide resin having a good appearance. . In particular, in the case of intake manifolds for automobile engines, when mixed gas of gasoline and air flows through the hollow part inside the molded product, if the appearance of the inner surface is poor (poor smoothness), the mixed gas flow is disturbed. , The fuel efficiency of the car engine will decrease. Recently, appearance is becoming more important.

[0004]

Means for Solving the Problems Accordingly, the present inventors have:
As a result of intensive studies, a specific polyamide resin composition containing a glass fiber having a non-circular cross section having a ratio of major axis to minor axis of 1.3 to 10 in a cross section perpendicular to the longitudinal direction is used, and appropriate vibration is obtained. The inventors have found that by selecting the welding conditions, the warpage can be improved without lowering the welding strength, and a vibration welded molded product having a good appearance can be obtained, and the present invention has been achieved.

That is, according to the present invention, (a) relative viscosity 2.
50 to 80% by weight of polyamide resin of 5 to 4.0, (b)
The ratio of major axis to minor axis is 1.3 in the cross section perpendicular to the length direction.
20 to 50% by weight of glass fiber having a non-circular cross section
And (c) a plate-shaped filler of 0 to 30% by weight,
A polyamide resin vibration-welded hollow-body molded article obtained by vibration-welding a plurality of hollow-body parts that are primarily molded using a polyamide resin composition in which the total amount of (b) and (c) is 20 to 50% by weight. .

The polyamide resin used in the present invention is made of a polymerizable ω-amino acid or a lactam thereof, preferably a lactam having 3 or more membered rings, or a dibasic acid and a diamine, and polycondensation thereof. It is a polyamide resin obtained by. Specifically, examples of the raw material ω-amino acids include 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, and 11-aminoundecanoic acid. Examples of lactams include ε-caprolactam, enantolactam, capryllactam, lauryllactam, α-pyrrolidone, and α-piperidone. As dibasic acids, adipic acid, glutaric acid,
Pimelic acid, suberic acid, azelaic acid, sebacic acid,
Undecanedioic acid, dodecadioic acid, hexadecadioic acid, hexadecenedioic acid, eicosandioic acid, eicosadiendioic acid, diglycolic acid, 2,2,4-
Trimethyl adipic acid, xylylene dicarboxylic acid, 1,
4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid can be mentioned. The diamines include hexamethylenediamine, tetramethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4 (or 2,4,4)-
Trimethylhexamethylenediamine, bis- (4,4 '
-Aminocyclohexyl) methane and metaxylylenediamine.

Among the polyamide resins used in the present invention, poly-ε-caprolactam is preferred. This is ε
-Caprolactam can be obtained by polycondensation alone, or can be obtained by polycondensation mainly with ε-caprolactam together with other raw materials such as lactams, ω-amino acids, dibasic acids and diamines exemplified above. In the latter case of copolycondensation, it is advisable to select a polyamide resin containing at least 5% by weight of ε-caprolactam.

The polyamide resin used in the present invention preferably has a degree of polymerization within a certain range, that is, a viscosity. A preferable relative viscosity is a value measured according to JIS K 6810 at a concentration of 98% sulfuric acid of 1% and a temperature of 25 ° C., and is selected from the range of 2.5 to 4.0, particularly preferably 2.8 to 3.7. If the relative viscosity is low, the welding strength will be low, while if it is too high, the fluidity will be impaired and the appearance will be poor, such being undesirable.

The end of the polyamide resin used in the present invention may be capped with a carboxylic acid or an amine, and a polyamide resin capped with a carboxylic acid or an amine having 6 to 22 carbon atoms is particularly desirable. . Specific examples of the carboxylic acid used for sealing include aliphatic monocarboxylic acids such as caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid. Examples of amines include aliphatic primary amines such as hexylamine, octylamine, decylamine, laurylamine, myristylamine, palmitylamine, stearylamine, and behenylamine. The amount of carboxylic acid or amine used for sealing is preferably about 30 μeq / g.

The glass fiber having a non-circular cross section used in the present invention is required to have a ratio of major axis to minor axis of 1.3 to 10 in a cross section perpendicular to the length direction. This ratio is 1.
Those having 5 to 6 are preferable, and those having 1.7 to 4.5 are particularly preferable. Here, the major axis is the distance when the linear distance between any two points on the cross-sectional figure becomes maximum,
The minor axis is the straight line orthogonal to the major axis that has the maximum distance between two points intersecting the cross-sectional figure.

The glass fiber having a non-circular cross-section is not particularly limited in its cross-sectional shape as long as it has a predetermined ratio of major axis to minor axis. A rectangular shape, a parallelogram, or a shape similar to these is used. Practically, those belonging to the eyebrows are preferable. The fiber length is usually 1 to 10 mm, preferably 2 to 5 mm.
Moreover, the compounding quantity of glass fiber is 20-50 weight% with respect to the total weight of a polyamide resin composition, Preferably it is 30-4.
An amount corresponding to 5% by weight is used. If the blending amount is too small, the welding strength will decrease, and if it is too large, the appearance will be poor.

In the present invention, in order to improve the warpage, a plate-like inorganic filler may be used in combination with the above-mentioned glass fiber having a non-circular cross section when compounding the polyamide resin composition. Examples of the plate-like inorganic filler generally include glass flakes, mica, metal foil and the like. The blending amount is 0 to 30% by weight, preferably 0 to 1
It is 5% by weight. If too much, the sled will be smaller, but
It is not preferable because the welding strength is lowered. Further, when used in combination, the total amount of the filler, which is a combination of the glass fiber having a non-circular cross section and the plate-like inorganic filler, is preferably 20 to 50% by weight based on the total weight of the polyamide resin composition. . If it is too small, the welding strength will decrease, and if it is too large, the appearance will deteriorate, which is not preferable. Further, these both fillers may be surface-treated with an aminosilane coupling agent, an epoxysilane coupling agent or the like, if necessary.

In the present invention, when the polyamide resin composition is blended, in addition to the filler, a release agent,
Various additives such as a lubricant, a heat stabilizer, a spreading agent, a plasticizer and a coloring agent can also be used. Further, these blending can be carried out in any step from polymerization to molding, and usually,
It is preferable to melt and knead using an extruder.

In the present invention, a plurality of hollow body parts are first formed by using these resin compositions. next,
A plurality of primary molded hollow body parts are joined by vibration welding to obtain a desired hollow body molded article. Therefore, even a hollow body molded product having a complicated structure that cannot be molded by one-step molding can be manufactured. If the hollow body molded article has a large warp, a problem occurs during assembly. Further, if the warp of the primary molded product is large, vibration welding becomes difficult, and the pressing force at the time of vibration welding becomes non-uniform, so that the welding strength of the target molded product decreases. Therefore, it is important to select various conditions so as to be at least 20 kgf or more, expressed by the welding strength by the measuring method described later.

The machine used for vibration welding is not particularly limited, and a commercially available one can be used. That is, using a vibration welding machine, to a plurality of hollow body parts to be joined, vibration having a required frequency and amplitude is applied, and when kept under a predetermined pressure for a predetermined time, due to the friction heat generated at the pressing joint surface, The surface of the hollow body component is melted and welded. The frequency of the vibration applied to the pressing surface depends on the hardness of the resin composition used, but is usually about 100 to 300 Hz, and the amplitude is 0.
It is 5 to 2.0 mm, preferably 0.8 to 1.6 mm. The welding pressure is 5 to 100 kg / cm ² , preferably 10 to 60 kg / cm ² , and particularly preferably 15 to 45.
kg / cm ² is selected. If the welding pressure is too high or too low, the welding strength will decrease. The welding time that should be under a predetermined pressure is set so that a target melting margin is obtained, and the holding time after releasing the pressure is set so that the welded portion is sufficiently solidified.

[0016]

EXAMPLES The present invention will now be described with reference to Examples, Test Examples 1 to 7 and Comparative Examples 1 to 11, but these do not limit the present invention in any way. The physical properties were evaluated by the following procedure.

1) Welding strength a) Test piece: A 100 mm square sheet having a thickness of 3 mm (hereinafter referred to as "100 square sheet") was primarily molded under the same conditions as those of the examples described later, and then, as shown in FIG. Two parts (1), (1 ') (L width of the part is 3 mm, only the bottom of the L shape of the part (1) is increased by 4 mm.
The L-shaped internal angle is R2, and the bottom angle is R1), and vibration welding is performed under the same conditions as in the examples described later to obtain a test piece (2) shown in FIG. 3 (b). b) Measurement method: Using a Tensilon UTM-III-100 type tensile tester manufactured by Orientec Co., Ltd., this test piece was pulled at a pulling speed of 5 mm / sec, and the chuck (3) (3 ') shown in FIG. 3 (b) was used. The strength at break was measured by pulling under a condition of a distance of 60 mm, and the strength was expressed in kgf, which was taken as the welding strength. The larger the value, the better the welding can be evaluated.

2) Disc warpage amount a) Test piece: A disc having a thickness of 16 mm and a diameter of 100 mm (hereinafter referred to as "100φ disc") was subjected to primary molding under the same conditions as those in Examples described later, and tested. Get a piece. b) Measuring method: This disk test piece is placed on a horizontal surface plate, and using a three-dimensional dimension measuring machine manufactured by Tokyo Seimitsu Co., Ltd., at four locations where the circumference of the disk is equally divided, The height of the bottom surface of the test piece from the surface of the surface plate was measured, and the average value (unit: mm) of the heights at four locations was taken as the disc warpage amount. The smaller the value, the better.

3) Appearance The surface smoothness (floating condition of the glass fiber used) of the 100 square sheet and 100φ disc test pieces prepared for both of the above tests was visually observed. In the evaluation, the surface smoothness of Comparative Example 1 was used as a standard, the same degree as this was indicated by the symbol ◯, those superior to this were ⊚, inferior ones were Δ,
Remarkably inferior ones are shown by x.

In the following examples and the like, the terms and abbreviations used have the following meanings. (Terms or abbreviations) (Meaning) 66 nylon 66 66 66 nylon eyebrow GF Nitto Boseki Co., Ltd., trade name CSH3PA870. Eyeglass-shaped cross-section glass fiber, ratio of major axis to minor axis 2.0 ± 0.3. Fiber length 3 mm. GF Nippon Electric Glass Co., Ltd., trade name T283H. Circular cross-section glass fiber, ratio of major axis to minor axis 1. Fiber length: 10 μm Flaca Nippon Nippon Glass Co., Ltd., trade name Flaca 101. Glass flakes. Mica manufactured by Yamaguchi Mica Co., Ltd., trade name Mica B-92.

EXAMPLE 6 Nylon having a relative viscosity (ηrel) of 3.0 and 35% by weight
"Mayu shape GF" of No. 1 was blended. A TEX30-HCT type twin-screw kneader manufactured by Nippon Steel Co., Ltd. was used for compounding, and the set temperature was 260 ° C. for 6 nylon and 2 for 66 nylon.
It was set to 80 ° C.

The polyamide resin composition thus kneaded is subjected to primary molding using a J-100SA type injection molding machine manufactured by Nippon Steel Co., Ltd., and a pair shown in FIGS. 2 (a) and 2 (b) is obtained. A primary molded product was obtained. The set cylinder temperature is 260 ° C for 6 nylon and 2 for 66 nylon.
It was set to 80 ° C. Moreover, the set mold temperature was set to 80 ° C. in all cases. As shown in FIGS. 2 (a) and 2 (b), the joining surface of the primary molded product has, on the one hand, a central protrusion (5) to be melted at the time of joining and, on the other hand, a melted material. A peripheral protrusion (6) was provided to prevent outflow to the surface of the hollow body.

Then, a pair of the primary molded products was applied with a vibration welding machine under the trade name of Mini Vibration Welder manufactured by Nippon Emerson Co., Ltd. under a pressure of 30 kg.
f, welding pressure of molded product 58.8 kg / cm ² , amplitude 0.
By welding with 8 mm, a hollow body molded product (4) shown in FIG. 1 was obtained. The welding time was 4.0 seconds and the holding time was 3.0 seconds.

Test Examples 1 to 7 and Comparative Examples 1 to 11 Under the same conditions as in Examples, 6 nylon or 66 nylon was used, and the amount of the glass fiber having the cocoon-shaped cross section and the glass fiber having the circular cross section shown in Table 1 were used. , Glass flakes and /
Or mix mica, perform primary molding, vibration welding,
The test pieces were obtained. In each test example and comparative example,
The results of evaluation of physical properties of the test pieces are also shown in Table 1.

[0025]

[Table 1]

Comparing each test example with the comparative example, in the present invention, a result is obtained which has a welding strength of 20 kgf or more, a disc warpage amount of 1 mm or less and an excellent appearance indicated by ⊚ to ∘. I understand that. It is also clear that the intended purpose can be achieved for the first time by selecting the relative viscosity of the polyamide resin, the glass fiber having a non-circular cross section, the amount used and the total amount of filler.

[0027]

As is apparent from the detailed description of the invention and the examples, according to the present invention, the warpage is improved without lowering the welding strength, and the vibration of polyamide resin having a good appearance is obtained. The welded hollow molded article can be manufactured efficiently and economically. In addition, when the molded body is an intake manifold, the safety during engine backfire is enhanced and the flow of mixed gas is smooth,
It has extremely great industrial significance.

[Brief description of drawings]

FIG. 1 is a conceptual perspective view showing an example of a hollow body molded product of the present invention.

FIG. 2 is a front view showing an example of a pair of primary molded products.

FIG. 3 is a plan view of a test piece and a welding test piece used for measuring the welding strength.

[Explanation of symbols]

 1, 1'Part of test piece 2 Welding test piece 3, 3'Chuck for tensile test 4 Hollow body molded product 5 Central protrusion 6 Perimeter protrusion

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuya Hitomi 5-6-2 Higashi-Hachiman, Hiratsuka City, Kanagawa Sanryo Engineering Plastics Co., Ltd. Chigasaki

Claims (4)

[Claims] 1. A polyamide resin having a relative viscosity of 2.5 to 4.0, 50 to 80% by weight, and (b) a ratio of major axis to minor axis of 1.3 to 10 in a cross section perpendicular to the longitudinal direction. A glass fiber having a non-circular cross section of 20 to 50
Wt% and (c) 0 to 30 wt% of the plate-like filler, and a plurality of hollow body parts formed by primary molding using a polyamide resin composition in which the total amount of (b) and (c) is 20 to 50 wt%. A vibration-bonded hollow body molded product made of polyamide resin, which is obtained by vibration-welding. 2. A vibration-welded hollow body molded product made of a polyamide resin according to claim 1, wherein the polyamide resin is 6 nylon. 3. The vibration welded hollow body molded product made of a polyamide resin according to claim 1, wherein the hollow body molded product is an intake manifold of an automobile engine. 4. The production of a polyamide resin vibration-welded hollow body molded article according to claim 1, wherein the vibration welding is carried out at a welding pressure of 5-100 kg / cm ² by vibration with an amplitude of 0.5-2.0 mm. Method.