JPH10180877A - Vibration welded molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration welded molded product improved in the strength of a welded part. SOLUTION: This molded product is composed of a nylon resin compsn. and constituted by bonding two or more molded pieces having vibration welding surfaces constituted of curved surfaces or a plurality of curved surfaces and flat surfaces by vibration welding. In this case, the thickness of the molten and re-solidified layer of a welded part is set to 40μm or more over the total welded part and the difference between the max. thickness and min. thickness of the melted and re-solidified layer is set to 50μm or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration-welded molded product obtained by molding a nylon resin composition and then joining it by vibration welding.

[0002]

2. Description of the Related Art In recent years, with the spread of uses of nylon resins, parts having more complicated shapes have been demanded. In particular, it is difficult to manufacture hollow molded products such as an intake manifold for an automobile and an oil tank using only the conventional injection molding method. As a method of manufacturing such a complicated molded product, a method of dividing and molding into two or more molded products and then welding them may be used. A molded product obtained by welding is required to have a high strength at the welded portion. In particular, hollow molded products such as automobile intake manifolds and oil tanks may be ruptured when the internal pressure increases if the strength of the welded portion is insufficient.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a vibration-welded molded article having excellent welding strength during welding.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, have reached the present invention.

That is, the present invention relates to a vibration welding molded product in which two or more molded pieces made of a nylon resin composition are joined by vibration welding, and the vibration welding surface is constituted by a curved surface or a plurality of curved surfaces and a flat surface. The thickness of the molten re-solidified layer at the vibration welded portion is 4% over the entire welded portion.
0 μm or more, and the difference between the maximum melt re-solidified layer thickness and the minimum melt re-solidified layer thickness is 100 μm or less, preferably 50 μm or less.
It is intended to provide a vibration-welded molded product characterized by having a thickness of not more than μm.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The nylon resin used in the present invention is obtained by polycondensation of polymerizable aminocarboxylic acids or their lactams, or dicarboxylic acids and diamines as raw materials. is there.

[0007] Specific examples of aminocarboxylic acids include 6
-Aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid. These amino acids can be used as a mixture of two or more.

The lactams include valerolactam, caprolactam, enantholactam, caprylactam,
Examples include laurolactam and the like. Of these, use of caprolactam and laurolactam is preferred, and use of ε-caprolactam is most preferred. In addition, these lactams can also be used in a mixture of two or more.

The dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid,
Suberic acid, azelaic acid, sebacic acid, undecandioic acid, dodecandioic acid, prasillic acid, tetradecandioic acid,
Examples include aliphatic dicarboxylic acids such as pentadecandioic acid and octadecandioic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalene diacid. . In addition, these dicarboxylic acids can be used in a mixture of two or more.

As diamines, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 2-methyl-1,5-diaminopentane (MD
P), 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,13-diaminotriene Decane, 1,
14-diaminotetradecane, 1,15-diaminopentadecane, 1,16-diaminohexadecane, 1,17
Aliphatic diamines such as diaminoheptadecane, 1,18-diaminooctadecane, 1,19-diaminononadecane, 1,20-diaminoeicosane, cyclohexanediamine, bis- (4,4-aminohexyl) methane; Examples thereof include alicyclic diamines and aromatic diamines such as xylylenediamine. These diamines are 2
Mixtures of more than one species can also be used.

[0011] Among the nylon resins used in the present invention,
Nylon 6, Nylon 66, Nylon 6/66 copolymer, Nylon 66 / 6T copolymer, Nylon 6T / 6
The use of an I-based copolymer, a nylon 6T / MPDT-based copolymer or the like is preferred, and the use of nylon 6, nylon 66, or a nylon 6 / 66-based copolymer is more preferred. Nylon 6, a nylon 6 component and a nylon 66 component The use of copolymerized nylon consisting of These nylon resins can be used in a mixture of two or more.

The nylon 6/66 copolymer which is one of the nylon resins preferably used in the present invention is nylon 6/66.
Copolymer of 98 to 80% by weight of component and 2 to 20% by weight of nylon 66 component or 98 to 80 of nylon 66 component
A copolymer consisting of 97 to 90% by weight of nylon 6 component and 3 to 10% by weight of nylon 66 component or 97 to 90% by weight of nylon 66 component. And nylon 6 ingredients 3-10
More preferably, it is a copolymer composed of% by weight.

Although the molecular weight of the nylon resin used in the present invention is not particularly limited, the relative viscosity in 98% sulfuric acid is 2.
It is preferably from 0 to 4.0, more preferably from 2.1 to 3.8, and most preferably from 2.2 to 3.6.
If the relative viscosity is less than 2.0, the welding strength is reduced,
If it exceeds 4.0, the fluidity during molding is undesirably reduced.

The terminal of the nylon resin used in the present invention can be blocked with a carboxylic acid compound or an amine compound as required.

Specific examples of the carboxylic acid compound include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, myristoleic acid, Aliphatic monocarboxylic acids such as palmitic acid, stearic acid, oleic acid, linoleic acid, arachinic acid, cyclohexanecarboxylic acid, methylcyclohexanecarboxylic acid, benzoic acid, toluic acid, ethylbenzoic acid , Aromatic monocarboxylic acids such as phenylacetic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandioic acid, dodecandioic acid, plasic acid, Like tetradecandioic acid, pentadecandioic acid, octadecandioic acid Aliphatic dicarboxylic acids, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, and aromatic dicarboxylic acids such as naphthalene diacid, and the like.

Specific examples of the amine compound include butylamine, pentylamine, hexylamine, heptylamine, octylamine, 2-ethylhexylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, and pentaamine. Alicyclic monoamines such as decylamine, hexadecylamine, octadecylamine, nonadecylamine, aliphatic monoamines of icosylamine, cyclohexylamine, methylcyclohexylamine, benzylamine, β
Aromatic monoamines such as phenylethylamine,
1,4-diaminobutane, 1,5-diaminopentane,
1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1, 13-diaminotridecane, 1,14-diaminotetradecane,
1,15-diaminopentadecane, 1,16-diaminohexadecane, 1,17-diaminoheptadecane, 1,
Aliphatic diamines such as 18-diaminooctadecane, 1,19-diaminononadecane, and 1,20-diaminoeicosane; cyclohexanediamine; alicyclic diamines such as bis- (4,4-aminohexyl) methane; And aromatic diamines such as amines.

The nylon resin used in the present invention may optionally contain glass fibers. There is no particular limitation on the type of glass fiber, and those used for ordinary resin reinforcement can be used. The cross-sectional shape is not particularly limited, but a circular cross-sectional shape can be used. There is no particular limitation on the fiber diameter, and the fiber diameter is preferably 3 to 15 μm.
The surface treatment of the glass fiber is not particularly limited, but a surface treatment with aminosilane, epoxysilane, or the like is effective. A molded product obtained by molding a resin composition to which glass fiber is added is excellent in heat resistance, strength and the like, and is one of the preferred embodiments in the molded product of the present invention. When glass fiber is added, the amount added is as follows.
5 to 200 parts by weight, preferably 10 parts by weight,
~ 150 parts by weight is more preferred.

The nylon resin used in the present invention may contain various fillers other than glass fibers, if necessary. Carbon fiber as a filler other than glass fiber,
Polymer fibers such as aramid fibers, potassium titanate fibers, gypsum fibers, brass fibers, stainless steel fibers, steel fibers, ceramic fibers, boron whisker fibers, mica, talc, silica, calcium carbonate, glass beads,
Fibrous, powdery, granular, or plate-like inorganic fillers such as glass flakes, glass microballoons, clay, wollastonite, and titanium oxide can be used.
When various fillers other than glass fibers are added, the amount is preferably 1 to 200 parts by weight, more preferably 3 to 150 parts by weight, per 100 parts by weight of the resin component.

The nylon resin used in the present invention includes an antioxidant and a heat stabilizer (for example, hindered phenol type, hydroquinone type, phosphite type and substituted products thereof, copper iodide, potassium iodide, etc.), UV absorbers (eg, resorcinol, salicylate, benzotriazole, benzophenone, hindered amine, etc.), lubricants and release agents (montanic acid and its salts, esters, half esters, stearyl alcohol, stearylamide and polyethylene wax) Metal stearates such as stearic acid, sodium stearate, barium stearate, aluminum stearate, dyes (eg, nigrosine) and pigments (eg, cadmium sulfide, phthalocyanine,
Ordinary additives such as a coloring agent containing carbon black and titanium oxide, and an antistatic agent can be added to impart predetermined characteristics.

The vibration-welded molded article of the present invention can be obtained by subjecting a nylon resin composition to primary molding, obtaining a primary molded article, and joining the obtained primary molded article by vibration welding. The primary molding of the nylon resin composition can be performed by a commonly used molding method, but is preferably performed by injection molding, blow molding, or extrusion molding, and more preferably performed by injection molding or blow molding. There is no particular limitation on the shape of the primary molded product, but in the present invention, an object in which the vibration welding surface of the primary molded product is a curved surface or a plurality of curved surfaces and a flat surface is applicable.

The vibration welding is performed using a vibration welding machine. The vibration welding machine is not particularly limited, and a commercially available vibration welding machine can be used.

The molten re-solidified layer, which is a main component in the present invention, refers to a portion which has been once melted during vibration welding and then solidified again upon cooling. The molten re-solidified layer takes a structure different from that of the unmelted portion crystallized in the mold at the time of molding by rapid cooling in air after stopping vibration in the vibration welding step. In the present invention, the thickness of the molten re-solidified layer is measured by observing the section of the welded portion with a polarizing microscope. In observing the cross section of the welded portion with a polarizing microscope, a structure having a polarization behavior different from that of the non-melted portion was determined to be a melt-resolidified layer. The thickness of the melt-resolidified layer of the molded article of the present invention is 40 μm or more, preferably 40 to 500 μm, and more preferably 50 to 500 μm. If it is less than 40 μm, sufficient welding strength cannot be obtained, which is not preferable. In the present invention, the difference between the maximum value and the minimum value of the thickness of the molten re-solidified layer of one vibration-welded molded product is 100 μm or less, preferably 5 μm or less.
When the thickness is 0 μm or less, the resistance of the welded portion to external force is particularly excellent, so that the reliability of the entire product is enhanced. It is more preferable that the difference between the maximum and minimum values is 40 μm or less.

In the present invention, the oriented phase refers to a structure in which the polymer molecules are oriented in the same direction as the shear due to the shearing during the vibration welding, which is present in the molten and resolidified layer. In the present invention, the non-oriented phase refers to a structure that is not an oriented phase in the melt-solidified layer. The ratio of the oriented phase and the non-oriented phase in the molten and re-solidified layer was measured by observation with an optical microscope using polarized light. The polarization axis was set to 45 degrees with respect to the shear direction at the time of welding, and a portion through which light passed was defined as an oriented phase, and a portion through which light did not pass was defined as a non-oriented phase. In the molded article of the present invention, the proportion of the volume of the oriented phase in the melt-solidified layer is preferably 95% or less, more preferably 7% or less.
When it is in the range of 0 to 95%, the strength of the welded portion is improved, which is preferable.

[0024]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.

<Examples 1 to 15 and Comparative Examples 1 to 4> The shapes of the test pieces used for evaluating the welding strength are as shown in FIGS. The welding surface of the test piece shown in FIG.
A rib having a width of 2.0 mm and a height of 2.0 mm is provided. At the time of welding, the rib 1 is melted and joined by friction. The test pieces having the shapes shown in FIGS. 1 and 2 were injection molded using Toshiba Corporation's IS-100F1. Cylinder temperature is 260 ° C. for nylon 6 or a copolymerized nylon or blend containing nylon 6 as a main component, and 280 ° C. for nylon 66 or a copolymerized nylon or blend containing nylon 66 as a main component. And the mold temperature was 80 ° C. Using the obtained test pieces having the shapes shown in FIGS. 1 and 2, welding was performed using a vibration welder Branson 2850 manufactured by Branson Corporation. The welding was performed under the conditions of a frequency of 240 Hz, a pressure of 50 to 300 kgf, a melting allowance of 0.1 to 1.5 mm, an amplitude of 1.5 mm, and a holding time of 10 seconds. FIG. 2 shows the shape of the hollow molded product obtained by welding. The obtained hollow molded article was filled with water, an internal pressure was applied to the hollow molded article in a water tank, and the pressure at the time of burst was defined as the welding strength.

The periphery of the welded part of the hollow molded article obtained by welding was cut out at intervals of 10 mm, which is a small enough interval for measuring the uniformity of the weld. After freezing using liquid nitrogen, the sample was observed under an optical microscope by freeze-cutting into a thin piece having a length of 3 mm, a width of 1 mm, and a thickness of 10 μm.
For freeze cutting, ULTARACUTS S manufactured by Leica was used. The freezing cutting was performed so that the cutting surface at the time of the freezing cutting was a surface orthogonal to the welding surface.

The thickness of the melt-resolidified layer and the ratio between the oriented phase and the non-oriented phase were determined by observing an optical microscope photograph using polarized light.
It was calculated by performing image processing using a scanner GT-9500 manufactured by EPSON Corporation and a personal computer FMV-DESK POWER SE manufactured by Fujitsu Limited.

Table 1 summarizes the experimental conditions and evaluation results in the examples and comparative examples.

[0029]

[Table 1] Abbreviations in Table 1 are as follows. N6: Nylon 6 N66: Nylon 66 N6 / 66 (1): Copolymerized nylon composed of 95% by weight of Nylon 6 component and 5% by weight of Nylon 66 component N6 / 66 (2): 80% by weight of Nylon 6 component and Nylon 66 component 20% by weight of copolymerized nylon N66 / 6: 95% by weight of nylon 66 component and 5% by weight of nylon 6 component Copolymerized nylon N6 // N6 / 66: Nylon 6 component 95 based on 100 parts by weight of nylon 6 resin 5% by weight and nylon 66 component 5
N6 // N66: 100 parts by weight of nylon 6 resin blended with 100 parts by weight of nylon 66 resin GF: glass fiber, fiber diameter 10 μm ηr: nylon resin Viscosity at 1% concentration in 98% sulfuric acid

Comparing the example with the comparative example, it can be seen that a molded article having a thickness of the melt-resolidified layer within the range of the present invention has excellent welding strength.

[0031]

As apparent from the detailed description of the present invention and the examples, the molded product of the present invention is a vibration-welded molded product in which the strength of the welded portion is improved.

[Brief description of the drawings]

FIG. 1 is a test piece used for evaluation of welding strength in Examples.
A is a plan view, B is a front view, C is a right side view, and D is a bottom view.

FIG. 2 is a test piece used for evaluation of welding strength in Examples.
A is a plan view, B is a front view, and C is a right side view.

FIG. 3 is a hollow molded product obtained by joining the test pieces of FIGS. 1 and 2 by welding. A is a plan view, B is a front view, and C is a right side view.

[Explanation of symbols]

 1: rib

Claims (8)

[Claims] 1. A vibration-welded molded product in which two or more molded pieces made of a nylon resin composition are joined by vibration welding.
The vibration welding surface is formed of a curved surface or a plurality of curved surfaces and a flat surface, and the thickness of the molten resolidified layer at the vibration welded portion is 40 μm or more over the entire welded portion, and the maximum melt resolidified layer is A difference between the thickness and the thickness of the minimum melt-resolidification layer is 50 μm or less. 2. The vibration-welded molded article according to claim 1, wherein the thickness of the molten re-solidified layer is in the range of 40 to 500 μm over the entire welded portion. 3. The vibration-welded molded article according to claim 1, wherein the ratio of the oriented layer to the non-oriented layer in the melt-resolidified layer is in the range of 95: 5 to 70:30. 4. The vibration welded molded article according to claim 1, wherein the nylon resin is at least one selected from aliphatic nylon resins having a melting point of 200 ° C. or higher. 5. The vibration welding molding according to claim 1, wherein the nylon resin is at least one selected from the group consisting of nylon 66, nylon 6, and copolymerized nylon containing these as a main component. Goods. 6. The vibration-welded molded article according to claim 5, wherein the copolymerized nylon is a copolymer comprising a nylon 6 component and a nylon 66 component. 7. The copolymerized nylon is a nylon 6 component of 98-8.
7. The vibration welding molding according to claim 6, which is a copolymer comprising 0% by weight and 2 to 20% by weight of nylon 66 component or a copolymer comprising 98 to 80% by weight of nylon 66 component and 2 to 20% by weight of nylon 6. Goods. 8. The copolymerized nylon has a nylon 6 component of 97-9.
The vibration welding molding according to claim 7, which is a copolymer comprising 0% by weight and 3 to 10% by weight of nylon 66 component or a copolymer comprising 97 to 90% by weight of nylon 66 component and 3 to 10% by weight of nylon 6. Goods.