JP2022102271A - Resin composition for cylindrical molding for laser beam welding, and cylindrical molding for laser beam welding using the same, and cylindrical molding-tube bond structure - Google Patents

Abstract

To provide a resin composition for a cylindrical molding for laser beam welding which can improve weldability when a cylindrical molding such as a connector for a tube for an automobile is welded by a laser beam, a cylindrical molding for laser beam welding using the same, and a bond structure obtained by welding the cylindrical molding for laser beam welding and a tube by a laser beam.SOLUTION: A resin composition for a cylindrical molding for laser beam welding contains the following components (A) to (C) in a specific ratio as a material of a connector 1 welded to a resin tube 2 by a laser beam. (A) At least one selected from the group consisting of polypropylene and polyamide (excluding (C)). (B) Glass fiber filler having a refractive index whose difference with the refractive index of (A) is 0.02 or less. (C) Compatibilizer having the same constitutional unit as the main chain of (A), and having a functional group showing reactivity to a hydroxyl group of the surface of (B) the glass fiber filler.SELECTED DRAWING: Figure 1

Description

The present invention comprises a resin composition for a laser-welded tubular molded body, a laser-welded tubular molded body using the same, and a bonded structure in which the laser-welded tubular molded body and a tube are laser-welded. (Cylindrical molded body-tube welded structure).

Conventionally, for the connection between the automobile tube and the connector, a fastening method such as press-fitting the automobile tube into a connector provided with an O-ring to ensure sealing property has been performed. However, in the above-mentioned fastening method, the number of parts such as seal parts such as O-rings increases, which causes an increase in assembly man-hours and an increase in cost.

Under such circumstances, in recent years, welding fastening has been attracting attention as a fastening method instead of press-fitting fastening using the above-mentioned sealing parts. Among the welding and fastening techniques for tubular members such as connectors that connect tubes, spin welding (welding using frictional heat due to rotation) is advantageous in that it can be welded with inexpensive equipment. It is known that there is.
However, spin welding has a problem that contamination due to the generation of burrs is likely to occur in the welded portion.
Therefore, laser welding is attracting attention as a method for solving the problem of contamination of the welded portion as described above.

In laser welding, the laser light transmitted through the laser transmitting material is absorbed by the laser absorbing material and generates heat, and the laser absorbing material melts, and at the same time, the transmitting material also melts due to heat transfer, so that the laser transmitting material and the laser absorbing material are melted. It is a method of welding.
The welding state due to the laser welding changes depending on the energy of the laser transmitted to the absorber, and is affected by the laser light output, the transmittance of the laser light of the transmitting material, the wall thickness of the transmitting material, and the like. If the energy of the laser beam is too small, welding failure occurs, and if the energy of the laser beam is too large, welding failure occurs due to material deterioration.
Therefore, in laser welding, it is required to suppress the variation in the transmittance of the laser transmitting material and to keep the energy of the laser light transmitted to the laser absorbing material constant.

Here, as a laser transmitting material specialized for laser welding as described above, for example, there is one shown in Patent Document 1.
In Patent Document 1, a polypropylene molded body is used as a laser transmitting material, and the polypropylene molded body improves the mechanical strength of the polypropylene molded body without impairing the transmission of laser light (laser welding performance). Therefore, it contains an inorganic filler having a refractive index similar to that of polypropylene. Then, an example using talc and white mica as the inorganic filler is shown.

Japanese Unexamined Patent Publication No. 2005-001350

However, in Patent Document 1, the problem of agglomeration of the filler caused by the generation of the weld portion, which is remarkably observed when manufacturing a tubular molded body such as a connector for an automobile tube, is sufficiently investigated. Has not been done.

That is, in the embodiment of Patent Document 1, the sheet material is manufactured by injection molding, but in the manufacture of the sheet material as described above, the flow direction of the resin by injection molding is usually one direction. Therefore, the weld portion is hardly generated, and the aggregation of the filler as described above hardly becomes a problem.
However, when the tubular molded body is manufactured, the flow directions of the resins are multidirectional, and weld portions are remarkably generated at the merging points, and the filler tends to be remarkably aggregated there.
Further, when the filler is the same as that used in the examples of Patent Document 1 (talc, white mica), sufficient strength (particularly high temperature strength) cannot be obtained when the connector is molded, so for example. It is considered to use a filler made of glass fiber, but generally commercially available glass fiber (glass fiber made of E glass or the like) has a higher refractive index than, for example, polypropylene. Therefore, there is a problem that the laser light is easily reflected at the interface between the base metal polymer and the glass fiber, and as a result, the laser transmittance is lowered and the amount of energy of the laser light transmitted to the laser absorber is lowered.
Therefore, it is considered to use a glass fiber having a refractive index close to that of polypropylene, but even in that case, if the laser beam hits the aggregated portion of the glass fiber, the laser beam is scattered. , There is a problem that good laser welding cannot be performed.
Therefore, the laser transmissive material disclosed in Patent Document 1 is tentatively a tubular molded body such as a connector for an automobile tube, and glass fiber is used as a filler thereof, and the open end edge of the tubular molded body is used. Even when the end of the resin tube is inserted inside and laser welded, the connector and tube cannot be sufficiently welded (the welding strength cannot be ensured over the entire circumference of the welded part), so the resin is used. There is a risk of problems such as leakage of fluid flowing through the tube and detachment of the resin tube from the tubular molded body.

The present invention has been made in view of such circumstances, and can improve the weldability and the like when laser welding a tubular molded body such as a connector for an automobile tube. A resin composition for a body, a laser-welded tubular molded body using the same, and a bonded structure in which the laser-welded tubular molded body and a tube are laser-welded (cylindrical molded body-tube bonded structure). ) Is the purpose.

The present inventors have conducted intensive studies to solve the above-mentioned problems. In the process of the research, at least one (A) selected from the group consisting of polypropylene and polyamide is used as the base material polymer as the material of the tubular molded body as described above, and the refraction of the base material polymer is used. A glass fiber filler (B) having a refractive index with a difference of 0.02 or less from the rate and a hydroxyl group on the surface of the glass fiber filler (B) having the same structural unit as the main chain of the base material polymer. It was recalled that the compatibilizer (C) having a functional group exhibiting reactivity with the glass was contained in the above material. As a result, the laser beam is transmitted at the interface of the glass fiber filler without being scattered, and the dispersibility of the glass fiber filler (B) is further improved. It is possible to reduce the aggregation of the glass fiber filler (B) in the weld portion. From these facts, it was found that the weldability at the time of laser welding can be improved, and the present invention has been reached.

That is, in order to achieve the above object, the present invention has the following [1] to [8] as its gist.
[1] Along with the base polymer composed of the following component (A), the following components (B) and (C) are contained, and the weight ratio of the components (B) and (C) is (B): (C). = 2: 0.01 to 2: 1 A resin composition for a laser-welded tubular molded body.
(A) At least one selected from the group consisting of polypropylene and polyamide (excluding (C)).
(B) A glass fiber filler having a refractive index with a difference of 0.02 or less from the refractive index of (A) above.
(C) A compatibilizer having the same structural unit as the main chain of the above (A) and having a functional group exhibiting reactivity with the hydroxyl group on the surface of the glass fiber filler of the above (B).
[2] The resin composition for a laser-welded tubular molded body according to [1], wherein the component (A) is polypropylene and the component (C) is maleic anhydride-modified polypropylene.
[3] The resin composition for a laser welded tubular molded body according to [2], wherein the maleic anhydride-modified polypropylene has a maleic anhydride modification rate of 0.1 to 4.0 mol%.
[4] The component (A) is a polyamide, and the component (C) is a polyamide having a melt volume rate (MVR) of 1 to 200 cm ^3/10 min measured at a measurement temperature of 180 ° C. and a load of 2.16 kg. , [1] The resin composition for a laser-welded tubular molded body according to [1].
[5] The laser welding according to any one of [1] to [4], wherein the content ratio of the component (B) to the total of the components (A) to (C) is 2.0 to 50% by weight. Resin composition for tubular molded products.
[6] A laser-welded tubular molded body comprising the resin composition for a laser-welded tubular molded body according to any one of [1] to [5].
[7] The laser welding tubular molded body according to [6], which is a connector for an automobile tube.
[8] The tubular shape characterized by being laser welded with the end portion of the resin tube inserted into the open end edge of the laser welded tubular molded body according to [6] or [7]. Mold-tube coupling structure.

From the above, the resin composition for a laser-welded tubular molded body of the present invention is injection-molded so as to have improved high-temperature strength and the like and to be a tubular molded body such as a connector for an automobile tube. It is possible to reduce the aggregation of the glass fiber filler in the weld portion that is remarkably generated at the time, and it is possible to improve the weldability when the tubular molded body is laser welded. Therefore, the laser-welded tubular molded body using the above resin composition also exhibits high laser welding property and the like. Further, the bonding strength of the bonded structure (cylindrical molded body-tube bonded structure) in which the laser welded tubular molded body and the tube are laser welded also improves the welding strength of the bonded portion (entire circumference of the welded portion). Therefore, problems such as leakage of fluid flowing through the tube and detachment of the tube from the tubular molded body can be solved.

It is sectional drawing which shows an example of the tubular molded body-tube connection structure of this invention.

Next, embodiments of the present invention will be described in detail. However, the present invention is not limited to this embodiment.

As described above, the resin composition for a laser-welded tubular molded product of the present invention contains the following components (B) and (C) together with the base material polymer composed of the following component (A). The weight ratio of the components (B) and (C) indicates (B) :( C) = 2: 0.01 to 2: 1.
(A) At least one selected from the group consisting of polypropylene and polyamide (excluding (C)).
(B) A glass fiber filler having a refractive index with a difference of 0.02 or less from the refractive index of (A) above.
(C) A compatibilizer having the same structural unit as the main chain of the above (A) and having a functional group exhibiting reactivity with the hydroxyl group on the surface of the glass fiber filler of the above (B).
In the present invention, the refractive index indicates the refractive index with respect to the laser beam of 1060 nm, and is d-line (587.6 nm), e-line (546.1 nm), and t-line (1013) with the precision refractometer KPR-3000. An approximate curve was prepared from (.98 nm), and the refractive index at 1060 nm was obtained. Therefore, the refractive index of each of the materials described below is obtained by this method.

Hereinafter, each material of the above resin composition will be described in detail.

[(A) component]
As the component (A) which is the base polymer of the above resin composition, at least one selected from the group consisting of polypropylene and polyamide (however, excluding the component (C) described later) is used. In the present invention, the base polymer has a great influence on the properties of the resin composition, and is usually 45% by weight or more, preferably 45% by weight or more, based on the total of the components (A) to (C). It occupies 45% by weight or more of the whole resin composition.

As the polypropylene, for example, a homopolypropylene homopolymer is preferable, but other olefin monomers such as ethylene and copolymers with other monomers such as (meth) acrylic acid ester may also be used. There may be. However, modified polypropylene such as maleic anhydride-modified polypropylene is excluded.
The polypropylene usually has a melt flow rate (MFR) of 0.1 to 50 g / 10 minutes measured at a measurement temperature of 190 ° C. and a load of 2.16 kg in accordance with JIS K 7210. The melt flow rate (MFR) is preferably 0.5 to 45 g / 10 minutes, more preferably 1 to 40 g / 10 minutes, and even more preferably 2 to 35 g / 10 minutes. The MFR can be measured using a melt indexer.
Further, as the polypropylene, those having a refractive index of 1.470 to 1.510 are usually used. The refractive index is preferably 1.475 to 1.505, more preferably 1.480 to 1.500, and even more preferably 1.485 to 1.495.

Examples of the polyamide include polyamide 6, polyamide 46, polyamide 66, polyamide 610, polyamide 612, polyamide 11, polyamide 12, polyamide 92, polyamide 99, polyamide 912, polyamide 1010, polyamide 6I, polyamide 6T, and polyamide 9T. , Polyamide 10T, Polyamide 11T, Polyamide MXD6, Polyamide 6T / 6I, Polyamide 6 / 6I, Polyamide 66 / 6T, Polyamide 66 / 6I, and at least two different structures among the polyamide components constituting these polyamides. A polyamide copolymer containing a component is used. These may be used alone or in combination of two or more. Among them, polyamide 12 is preferable because it has excellent calcium chloride resistance and can suppress cracks due to adhesion to a snow melting agent (calcium chloride resistant).
The above-mentioned polyamide is usually MVR (in the case of an aliphatic polyamide, a melt volume rate (MVR) measured at a measurement temperature of 275 ° C. and a load of 5 kg in accordance with JIS K 7210. In the case of an aromatic polyamide, it is a melt volume rate (MVR). According to JIS K 7210, a melt volume rate (MVR) measured at a measurement temperature of 325 ° C. and a load of 2.16 kg (MVR) is used at 0.1 to 40 cm for ^3/10 minutes, and the above MVR is preferably 0. .2 to 38 cm ^3/10 minutes, more preferably 0.3 to 35 cm ^3/10 minutes, still more preferably 0.4 to 30 cm ^3/10 minutes. The melt volume rate (MVR) of the above polyamide measured at a measurement temperature of 180 ° C. and a load of 2.16 kg according to JIS K 7210 is 0.1 cm ^3/10 minutes or less (high molecular weight). It is different from the component (C) of. The MVR can be measured using a melt indexer.
Further, as the above-mentioned polyamide, those having a refractive index of 1.51 to 1.55 are usually used. The refractive index is preferably 1.515 to 1.545, more preferably 1.52 to 1.54, and even more preferably 1.525 to 1.535.

[(B) component]
As the component (B), a glass fiber filler having a refractive index within 0.02 from the refractive index of the base polymer (component (A)) of the resin composition is used. The above difference in refractive index is preferably within 0.01, more preferably 0.
As described above, the glass fiber filler (B) to be used (the glass fiber filler having a difference in the refractive index within the above range) is determined by the selection (refractive index) of the base material polymer as the component (A).
The refractive index of the glass fiber filler is preferably 1.4 to 1.7, more preferably 1.44 to 1.64, and even more preferably 1.48 to 1.58.

The glass fibers used as the material of the glass fiber filler (B) include D glass (low dielectric constant glass), NE glass (low dielectric constant non-alkali glass), E glass (non-alkali glass), and C glass (acid resistant). Examples thereof include filamentous fibers obtained by melt-spinning glass such as (alkaline glass), A glass (alkali glass), S glass (high-strength / high-elasticity glass), and alkali-resistant glass. Among them, D glass and NE glass are preferably used because the difference in the refractive index from the refractive index of the base polymer as the component (A) is small.
Further, the fiber diameter of the glass fiber is preferably 2.5 to 20 μm, more preferably 5 to 15 μm from the viewpoint of injection molding processability and laser light transmission.

From the viewpoint of improving the high temperature strength of the tubular molded product, the content ratio of the component (B) to the total (100% by weight) of the components (A) to (C) in the resin composition is 2. It is preferably in the range of 0 to 50% by weight, more preferably 10 to 30% by weight, still more preferably 15 to 25% by weight.

[(C) component]
The component (C) has the same structural unit as the main chain of the base polymer (component (A)) of the resin composition, and is functionally reactive with the hydroxyl group on the surface of the glass fiber filler (B). A compatibilizer having a group (carboxylic acid group, carboxylic acid group anhydride, epoxy group, amide group, etc.) is used.
As described above, the main chain of the base polymer as the component (A) determines the compatibilizer to be used. When polypropylene and polyamide are used in combination as the component (A), a compatibilizer having the same structural unit as any of the main chains may be used.

Here, when the component (A) is polypropylene, as the compatibilizer (C), maleic anhydride-modified polypropylene, imine-modified polypropylene, or the like is used alone or in combination of two or more. Among them, maleic anhydride-modified polypropylene is preferable, and maleic anhydride-modified polypropylene having a maleic anhydride modification rate of 0.01 to 20 mol%, more preferably anhydrous, is preferable from the viewpoint of improving laser weldability in the tubular molded product. Polypropylene having a maleic anhydride modification rate of 0.05 to 10 mol%, particularly preferably polypropylene having a maleic anhydride modification rate of 0.1 to 5 mol%.
When the compatibilizer (C) is maleic anhydride-modified polypropylene or the like as described above, it is measured at a measurement temperature of 190 ° C. and a load of 2.16 kg in accordance with JIS K 7210 of the compatibilizer (C). The resulting melt flow rate (MFR) is preferably 0.1 to 400 g / 10 minutes, more preferably 0.3 to 300 g / 10 minutes, and even more preferably 0.1 to 200 g / 10 minutes. The MFR can be measured using a melt indexer.
Further, when the compatibilizer (C) is maleic anhydride-modified polypropylene or the like as described above, the refractive index of the compatibilizer (C) is preferably 1.475 to 1.505. The refractive index is more preferably 1.480 to 1.500, and even more preferably 1.485 to 1.495.
As described above, when the component (A) is polypropylene and the compatibilizer (C) is maleic anhydride-modified polypropylene or the like, the maleic anhydride group or the like of the compatibilizer (C) is glass fiber. It reacts with the hydroxyl group on the surface of the filler (B) and adheres to it, and the polypropylene portion of the compatibilizer (C) has excellent compatibility with the base polymer, so that the dispersibility is improved. As a result, the laser light transmittance, high temperature intensity, and the like in the tubular molded body are also improved.

When the component (A) is polyamide, the compatibilizer (C) is a melt volume rate (MVR) measured at a measurement temperature of 180 ° C. and a load of 2.16 kg in accordance with JIS K 7210. Polyamide (low molecular weight polyamide) having a temperature of 1 to 200 cm ^3/10 is used. Among them, from the viewpoint of improving the laser weldability in the tubular molded product, the MVR is preferably 2 to 175 cm ^3/10 minutes, more preferably 3 to 150 cm ^3/10 minutes, and further preferably 4 to 125 cm ³ / 10 minutes, particularly preferably 5-100 cm ^3/10 minutes. The MVR can be measured using a melt indexer.
The low molecular weight polyamide as described above is obtained from an excess of polyamine and a polybasic acid.
Further, as described above, when the component (A) is a polyamide and the compatibilizer (C) is a polyamide showing the above MVR (low molecular weight polyamide), the amount of terminal amide is increased by adding the low molecular weight polyamide. As the number increases, the reactivity with the hydroxyl group on the surface of the glass fiber filler (B) is improved. Since the low molecular weight polyamide has excellent compatibility with the base polymer, it prevents the glass fiber filler (B) from reaggregating and improves the dispersibility. As a result, the laser light transmittance, high temperature intensity, and the like in the tubular molded body are also improved.
Further, when the compatibilizer (C) is a low molecular weight polyamide as described above, the refractive index of the compatibilizer (C) is preferably 1.515 to 1.545. The refractive index is more preferably 1.52 to 1.54, still more preferably 1.525 to 1.535.

From the viewpoint of improving the laser weldability of the tubular molded product, the weight ratios of the components (B) and (C) in the above resin composition are (B): (C) = 2: 0.01 to It is 2: 1, preferably (B): (C) = 2: 0.02 to 2:0.5, and more preferably (B) :( C) = 2: 0.1 to 2: 0.3. Is the range of.

[Other ingredients]
In addition to the above components, the resin composition for a laser-welded tubular molded body of the present invention contains, if necessary, a colorant (dye and pigment) and heat stability within a type and range that does not impair the laser light transmission. Other components such as agents, antioxidants, inorganic fillers, crystal nucleating agents, weathering agents, plasticizing agents, lubricants, impact resistant materials and the like can be blended.

Examples of the dyes include azo dyes, anthraquinone dyes, perinone dyes, perylene dyes, phthalocyanine dyes, carbonium dyes, and indigoid dyes, oil dyes, acid dyes, basic dyes, and disperse dyes. Of these, perylene dyes are preferable because they have excellent laser transparency.

Examples of the pigment include phthalocyanine-based, anthraquinone-based, isoindoleinone-based, quinacridone-based, perylene-based, and azo-based organic pigments. Of these, perylene-based organic pigments are preferable because they have excellent laser transparency.

As described above, since the above-mentioned colorant needs to be used within a range that does not impair the laser light transmission, the content ratio of the colorant in the resin composition for a laser welded tubular molded article of the present invention is usually set. It is less than 1% by weight. From the above viewpoint, the content ratio of the colorant is preferably less than 0.75% by weight, more preferably less than 0.5% by weight.

<Manufacturing method of laser welding tubular molded body>
Next, the laser welding tubular molded body of the present invention is manufactured, for example, as follows.

That is, first, the base material polymer (A), the glass fiber (glass fiber filler (B)), the compatibilizer (C), and if necessary, other components are 200 by using a twin-screw extruder. Melt and knead at a cylinder temperature of ~ 260 ° C. Then, pellets are obtained from the melt-kneaded product (resin composition for a laser-welded tubular molded body of the present invention).
Next, using the pellets, injection molding is performed in a mold for a cylindrical molded body at a set temperature of 200 to 280 ° C. by an injection molding machine. In this way, the desired tubular molded body can be manufactured.

Further, as another production method, a base material polymer (A), a glass fiber (glass fiber filler (B)), a compatibilizer (C), and if necessary, other components are used for each shot. , The required amount may be directly charged into the injection molding machine, and the injection molding may be used to obtain the desired laser-welded tubular molded body.
Further, after a part of each of the above materials is mixed in advance, the required amount of the mixture is directly charged into the injection molding machine for each shot together with the remaining materials, and the target laser is subjected to the injection molding. A welded tubular molded product may be obtained.

The fiber length of the glass fiber used in the above various manufacturing methods is usually 2 to 6 mm, and preferably 3 to 5 mm. Since the glass fibers are broken in the melt kneader or the injection molding machine and the glass fibers become finer, the fiber length is usually different from the glass fiber length in the laser-welded tubular molded body.

<Laser welding tubular molded body>
The laser welded tubular molded body obtained as described above is usually a substantially tubular body having an inner diameter of 2.5 to 50 mm, a wall thickness of 0.25 to 10 mm, and a length of 20 to 1000 mm from the viewpoint of laser weldability and the like. It shows the shape of the shape. The inner diameter is preferably 3 to 45 mm, more preferably 3.5 to 40 mm, and even more preferably 4 to 35 mm. The wall thickness is preferably 0.5 to 7.5 mm, more preferably 0.75 to 5 mm, and even more preferably 1.0 to 3.0 mm. The length is preferably 25 to 500 mm, more preferably 30 to 250 mm, and even more preferably 35 to 100 mm.
Since the laser welding tubular molded body is "substantially tubular" as described above, the laser welding tubular molded body is not limited to a completely tubular one, and the end of the resin tube is contained within the open end edge thereof. Any shape may be used as long as it can be laser welded with the portion inserted.

When the total light transmittance at 1060 nm is measured with a spectrophotometer (for example, V-770 manufactured by Nippon Spectroscopy Co., Ltd.) for the laser-welded tubular molded body, the total light transmittance is 55%. The above is preferable, more preferably 57% or more, still more preferably 60% or more. The total light transmittance of the laser-welded tubular molded product with respect to the weld portion is preferably 50% or more, more preferably 52% or more, still more preferably 55% or more.

Further, the central portion (central portion with respect to the length direction) of the laser-welded tubular molded body is fixed, and in a cantilever state with a length of 10 mm, the pushing speed is 5 mm with respect to the opening at the tip of the tubular molded body. When the breaking strength (N) when the indenter (tip R2.0) of JIS K 7171 is pushed in the axial direction is measured by the compression evaluation of the tensile tester Strograph at / min, the breaking strength is 450N. The above is preferable, 500 N or more is more preferable, 550 N or more is further preferable, and 600 N or more is particularly preferable.

The laser welded tubular molded body of the present invention thus obtained is preferably used as a connector for an automobile tube, a connector for a water pipe, or the like. Of these, connectors for automobile tubes are more preferable.

<Cylindrical molded body-tube coupling structure>
FIG. 1 is a cross-sectional view showing an example of a tubular molded body-tube coupling structure of the present invention, in which 1 is a connector (cylindrical molded body) and 2 is a resin tube. The connector 1 is the laser welding tubular molding of the present invention. As shown in the figure, the laser light transmitted through the connector 1 by irradiating the laser light from the outside of the connector 1 with the end portion of the resin tube 2 inserted in the open end edge 1a of the connector 1. Is absorbed by the resin tube 2 and generates heat, and the base polymer of the resin tube 2 melts. Further, by transferring heat to the connector 1, the base polymer of the connector 1 is also melted. In this way, the interface between the two is welded.

Normally, the connector 1 and the resin tube 2 do not adhere to each other unless the base polymer is the same material, but the hot melt film is arranged on the open end edge 1a of the connector 1 or the welded surface of the resin tube 2. It is also possible to weld both by applying a surface treatment such as adhesive coating or electrostatic coating. Further, it is necessary to use a material (carbon black, inorganic pigment, organic pigment, dye, etc.) that absorbs laser light and generates heat for the material of the resin tube 2 or the welded surface of the resin tube 2. .. The resin tube 2 is usually long, and the length of the connector 1 is shorter than that of the resin tube 2.

As the laser used in the present invention, a laser having an oscillation wavelength of 800 to 1200 nm can be used, and a YAG laser, a semiconductor laser, a glass laser, a ruby laser, a He-Ne laser, a nitrogen laser, a chelate laser, a dye laser and the like can be used. A known laser can be applied. The output of these lasers is preferably about 5 to 40 W.

The laser irradiation time and the distance between the laser and the irradiated body (connector 1 and resin tube 2) need to be adjusted in consideration of the laser output, the thickness of the connector 1, the laser transmittance of the connector 1, and the like.

In the tubular molded body-tube coupling structure of the present invention, the resin tube 2 is inserted 1.5 cm into the open end edge of the connector 1, and the resin tube is kept in that state from the outside of the tubular molded body. When the laser beam is applied to a portion 10 mm from the position where 2 and the connector 1 start to overlap under the condition of a laser output of 40 W and 1 second / circumference, and the interface between the connector 1 and the resin tube 2 is welded. The welding strength (N) by the axial tensile evaluation by the tensile tester stroma is preferably 450 N or more, more preferably 475 N or more, and further preferably 500 N or more.

Hereinafter, examples will be described together with comparative examples. However, the present invention is not limited to these examples as long as the gist of the present invention is not exceeded.

First, tubular molded bodies of Examples and Comparative Examples were prepared according to the following. The refractive index of each material used in the tubular molded body indicates the refractive index with respect to the laser beam of 1060 nm, and the d-line (587.6 nm) and e-line (546.1 nm) of the precision refractometer KPR-3000. , The approximate curve was prepared from the t-line (1013.98 nm), and the refractive index at 1060 nm was obtained.

[Example 1]
Polypropylene (Product name: Novatec PP MA1B, manufactured by Nippon Polypropylene Co., Ltd., Refraction rate: 1.49, MFR (Measured at a measurement temperature of 190 ° C. and a load of 2.16 kg according to JIS K 7210): 21 g / 10 minutes) 79. 9 parts by weight and acid-modified polypropylene (product name: TPPP9232, manufactured by BYK, maleic anhydride-modified polypropylene, maleic anhydride modification rate: 2.0 mol%, refractive index: 1.49, MFR (JIS K 7210 compliant) , Measurement temperature 190 ° C, load 2.16 kg) 6 g / 10 minutes) 0.1 part by weight and glass fiber (GF) filler made of D glass (cut to a cut length of 3 mm, glass chopped with a fiber diameter of φ11 μm) Strand, refractive index: 1.48, product name: ECS (HL) -301TDS, manufactured by Chongqing International Composite Materials Co., Ltd. (CPIC), 20 parts by weight, and perylene-based colorant (product name: LUMOGEN Black K 0087, BASF) A mixture of 0.1 parts by weight (manufactured by Japan) was melt-kneaded at a cylinder temperature of 180 ° C. using a twin-screw extruder (screw diameter 30 mm) to obtain pellets.
Then, using the above pellets, injection molding was performed in a mold for a tubular molded body at a set temperature of 180 ° C. by an injection molding machine to produce a tubular molded body having an outer diameter of 12 mm, a wall thickness of 2 mm, and a length of 25 mm. ..

[Examples 2 to 4, Comparative Examples 1 to 8]
Each component shown in Table 1 below was blended in the ratio shown in the same table to prepare pellets in the same manner as in Example 1, and the pellets were used to obtain a tubular molded body similar to Example 1.
In Example 2 and Comparative Examples 1 to 4, the cylinder temperature of the twin-screw extruder and the set temperature of the injection molding machine were set to the same temperatures as in Example 1, and Examples 3 and 4 and Comparative Examples 5 to 8 were set. The cylinder temperature of the twin-screw extruder was 220 ° C, and the set temperature of the injection molding machine was 260 ° C.
In addition, "PA12" shown in Table 1 below is a polyamide 12 (product name: Grilamid L20, manufactured by Ems-Chemie, MVR (based on JIS K 7210, measured at a measurement temperature of 275 ° C. and a load of 5 kg): 85 cm ³ /. 10 minutes, refractive index: 1.53). The "low molecular weight PA" shown in Table 1 below is Platamid 2513 (manufactured by Arkema, MVR (measured at a measurement temperature of 180 ° C. and a load of 2.16 kg according to JIS K 7210): 24 cm ^3/10 min. , Refractive index: 1.53). Further, the "GF filler (E glass)" shown in Table 1 below is a glass fiber filler made of E glass (glass chopped strand having a fiber diameter of φ10 μm cut to a cut length of 3 mm, refractive index: 1.56, Product name: ECS305K, manufactured by Chongqing International Composite Materials Co., Ltd. (CPIC)), "GF filler (NE glass)" is a glass fiber filler made of NE glass (cut to a cut length of 3 mm, fiber diameter φ11 μm). Glass chopped strand, refractive index: 1.51, product name: New glass, manufactured by Nitto Spinning Co., Ltd., and "GF filler (D glass)" is a glass fiber filler made of D glass, as described above. A glass chopped strand with a fiber diameter of φ10 μm cut to a cut length of 3 mm, a refractive index of 1.48, a product name: ECS (HL) -301TDS, manufactured by Chongqing International Composite Materials Co., Ltd. (CPIC).

Then, each characteristic of the pellets and the tubular molded product obtained as described above was evaluated according to the following criteria. The results are also shown in Table 1 below.

<Connector strength>
The central part (central part with respect to the length direction) of each tubular molded body is fixed, and in a cantilever state with a length of 10 mm, the pushing speed is 5 mm / min with respect to the opening at the tip of the tubular molded body, JIS. The breaking strength (N) when the indenter (tip R2.0) of K 7171 was pushed in the axial direction was measured by the compression evaluation of the tensile tester Strograph. In the present invention, the breaking strength is usually required to be 450 N or more.

<Welding strength>
Which of the resin tubes A and B (which of the resin tubes A and B was used) produced as described below in the open end edge of each tubular molded body is shown in Tables 1 and 2 below. ) Insert 1.5 cm, and in that state, irradiate the part 10 mm from the position where the tube and the connector start to overlap from the outside of the tubular molded body with a laser beam of 1060 nm under the condition of laser output 40 W, 1 second / circumference. Then, the interface between the tubular molded body and the resin tube was welded (see FIG. 1). From the sample welded as described above, the welding strength (N) was measured by axial tensile evaluation using a tensile tester stromagraph, and evaluated according to the following criteria.
Welding strength 450N or more 〇 Welding strength less than 450N ×

The resin tubes A and B were produced as follows.

[Preparation of resin tube A]
A twin-screw extruder (product name: Novatec PP BC6C, manufactured by Nippon Polypropylene) containing 100 parts by weight and carbon black (product name: MCF # 45, manufactured by Mitsubishi Chemical Corporation) by 0.1 parts by weight are blended. Using a screw diameter of 30 nm), melt-kneading was performed at a cylinder temperature of 180 ° C. to obtain pellets.
Then, using the pellets, melt extrusion molding was performed at a set temperature of 180 ° C. using a melt extruder to prepare a resin tube A having an outer diameter of 8 mm and a wall thickness of 1.5 mm.

[Preparation of resin tube B]
Polyamide 12 (product name: Grillamid L25, manufactured by M. Chemi) and 0.1 part by weight of carbon black (product name: MCF # 45, manufactured by Mitsubishi Chemical Corporation) are blended and a twin-screw extruder (screw diameter) is blended. 30 nm) was melt-kneaded at a cylinder temperature of 220 ° C. to obtain pellets.
Then, using the pellets, melt extrusion molding was performed at a set temperature of 220 ° C. using a melt extruder to prepare a resin tube B having an outer diameter of 8 mm and a wall thickness of 1.5 mm.

<Laser transmittance>
Using pellets, which are the material of each tubular molded product, injection molding (injection in one direction) was performed in a mold for the sheet-shaped molded product at a set temperature of 260 ° C. using an injection molding machine to produce a sheet having a thickness of 2 mm. .. Then, the total light transmittance at 1060 nm was measured with respect to the above sheet using a spectrophotometer (manufactured by JASCO Corporation, V-770), and evaluated according to the following criteria.
Total light transmittance 55% or more 〇 Total light transmittance less than 55% ×

<Laser transmittance (weld evaluation)>
At the time of injection molding into the mold for the sheet-shaped molded body, injection was performed from two opposite directions so that a weld portion was intentionally formed to prepare a sheet (for weld evaluation) having a thickness of 2 mm. Then, the total light transmittance at 1060 nm was measured with respect to the weld portion of the above sheet using a spectrophotometer (manufactured by JASCO Corporation, V-770), and evaluated according to the following criteria.
Total light transmittance 50% or more 〇 Total light transmittance less than 50% ×

From the results in Table 1 above, in Examples 1 to 4, the difference in refractive index between the base polymer (polypropylene or PA12) and the GF filler in the material of the tubular molded body (connector) is small (within 0.02). Since the requirements specified in the present invention are satisfied, the connector strength is high, the total laser transmittance is high, and the total laser transmittance is high even when the weld portion is formed. Then, when the tubular molded body was laser welded to the resin tube, excellent welding strength was obtained.

On the other hand, in Comparative Examples 1, 2, 5 and 6, the difference in the refractive index between the base polymer (polypropylene or PA12) and the GF filler in the material of the tubular molded body (connector) is large, and as a result, the entire laser is used. The result was that the transmittance was low and the welding strength was also low. In Comparative Examples 3 and 7, the amount of the compatibilizer (acid-modified polypropylene or low molecular weight PA) added was large, resulting in a low total laser transmittance. In Comparative Examples 4 and 8, in the material of the tubular molded body (connector), "it has the same structural unit as the main chain of the base polymer and has a functional group exhibiting reactivity with the hydroxyl group on the surface of the GF filler. Since it does not contain a "compatible agent", the problem due to the aggregation of the GF filler during injection molding is not solved, resulting in a decrease in the total laser transmittance and a decrease in the welding strength.

In the resin composition for a tubular molded body for laser welding of the present invention, the glass fiber filler aggregates in a weld portion that is prominently generated when injection molding is performed so as to form a tubular molded body such as a connector for an automobile tube. It is possible to reduce the number of the above, and it is possible to improve the weldability when laser welding the tubular molded product. The tubular molded body can be applied to connectors for automobile tubes, connectors for water pipes, and the like. Further, as the welding target of the tubular molded body, it can be applied to a resin tube or the like.

1 Connector 2 Resin tube 1a End edge

Claims (8)

It contains the following components (B) and (C) together with the base polymer composed of the following component (A), and the weight ratio of the components (B) and (C) is (B) :( C) = 2: A resin composition for a laser-welded tubular molded body, which is 0.01 to 2: 1.
(A) At least one selected from the group consisting of polypropylene and polyamide (excluding (C)).
(B) A glass fiber filler having a refractive index with a difference of 0.02 or less from the refractive index of (A) above.
(C) A compatibilizer having the same structural unit as the main chain of the above (A) and having a functional group exhibiting reactivity with the hydroxyl group on the surface of the glass fiber filler of the above (B). The resin composition for a laser-welded tubular molded product according to claim 1, wherein the component (A) is polypropylene and the component (C) is maleic anhydride-modified polypropylene. The resin composition for a laser-welded tubular molded body according to claim 2, wherein the maleic anhydride-modified polypropylene has a maleic anhydride modification rate of 0.1 to 4.0 mol%. Claimed that the component (A) is a polyamide, and the component (C) is a polyamide having a melt volume rate (MVR) of 1 to 200 cm ^3/10 min measured at a measurement temperature of 180 ° C. and a load of 2.16 kg. 1. The resin composition for a tubular molded body to be welded by laser welding. The laser welding tubular shape according to any one of claims 1 to 4, wherein the content ratio of the component (B) to the total of the components (A) to (C) is 2.0 to 50% by weight. Resin composition for molded body. A laser welded tubular molded body comprising the resin composition for a laser welded tubular molded body according to any one of claims 1 to 5. The laser welding tubular molded body according to claim 6, which is a connector for an automobile tube. A tubular molded body-tube coupling structure, characterized in that the end of the resin tube is laser welded in a state where the end portion of the resin tube is inserted into the open end edge of the laser welded tubular molded body according to claim 6 or 7. body.

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