JP2011074394A - Resin composition for laser welding, laser welding method, and resin molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition for laser welding, which is excellent both in laser transmittance and in moldability. <P>SOLUTION: The resin composition for laser welding contains only polytrimethylene terephthalate substantially as a resin component. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  This divisional application claims the matters described in Examples 2 to 7 as inventions among the items described in the specification of the following original application.

  The present invention relates to a resin composition for laser welding. More specifically, the laser resin composition of the present invention relates to a composition containing polytrimethylene terephthalate as a resin component. The present invention relates to a laser welding method for the composition. The present invention relates to a resin molded product obtained by the laser welding method.

  As a method for joining resin members, a method using laser welding has been attracting attention (see, for example, Patent Document 1). In such a method, a laser-transmissive resin member and a laser-absorbing resin member are laminated, a laser is irradiated from the laser-transmissive resin member side, and the laser is irradiated to the interface between the two resin members. Then, both resin members are welded by heat generated by laser irradiation.

  As a resin constituting the laser transmissive resin member, polyester has attracted attention. As the polyester, polybutylene terephthalate (PBT) and polyethylene terephthalate (PET) have been proposed (for example, see Patent Document 2).

  PBT is excellent in moldability. However, since PBT is easily crystallized, its laser transmittance is low. Moreover, generally a laser absorptive additive is used for the laser-permeable resin member for the purpose other than improving the laser transmittance. In such a case, since the laser transmittance of the PBT resin member is further lowered, the use of the additive for the PBT resin member is limited. For these reasons, PBT is difficult to use as a resin member on the laser transmission side.

  On the other hand, PET has high laser transparency. However, there is a drawback that the moldability is poor. There is a technique of using a nucleating agent in order to improve moldability. However, if a nucleating agent is used, crystallization proceeds and there is a possibility that the laser transmittance may be lowered.

US Pat. No. 5,893,959 JP 2003-136601 A

  As described above, various laser-transmitting resin members have been disclosed, but there is a demand for a resin composition for laser welding that is excellent in both laser transmittance and moldability.

  Accordingly, an object of the present invention is to provide a resin composition for laser welding excellent in both laser permeability and moldability.

  The present invention relates to a resin composition for laser welding containing substantially only polytrimethylene terephthalate as a resin component. The laser welding resin composition of the present invention is used when a resin molded product is obtained by laser welding.

  Further, the present invention provides a step of preparing a laser transmissive first resin member substantially containing only polytrimethylene terephthalate as a resin component, and a step of preparing a laser absorbing second resin member containing a thermoplastic resin. And superposing the first resin member and the second resin member, transmitting the laser to the second resin member through the first resin member, and the first resin member and the second resin member. The present invention relates to a laser welding method including a step of welding a resin member.

  Furthermore, the present invention includes a laser-transmitting first resin member that substantially contains only polytrimethylene terephthalate as a resin component, and a laser-absorbing second resin member that is laser-welded to the first resin member. The present invention relates to a resin molded product.

  The laser welding resin composition of the present invention contains a predetermined amount of polytrimethylene terephthalate (PTT) as a resin component. PTT has a high laser transmittance and, in addition, a good moldability. For this reason, when the composition of the present invention is welded to another composition to obtain a molded product, it is possible to efficiently transmit a laser and realize excellent dimensional accuracy of the molded product. .

  In addition, since only PTT is included as a resin component, unexpected reductions in mechanical properties and thermal properties can be prevented and manufacturing costs can be reduced compared to the case of mixing resins. It is. In actual commercialization, this contribution to the reduction in manufacturing cost is a great advantage.

It is a schematic diagram explaining the laser welding method. It is a graph which shows the relationship between content of PTT, tensile strength, and elongation at break. It is a graph which shows the relationship between content of PTT, bending strength, and a bending elastic modulus. It is a graph which shows the relationship between content of PTT, and the transmittance | permeability.

(Laser welding resin composition)
The present invention relates to a resin composition for laser welding using polytrimethylene terephthalate, which is excellent in both laser permeability and moldability. In particular, the composition of the present invention is a composition that improves production efficiency in laser welding with other compositions by utilizing the excellent laser transmittance and excellent moldability of PTT.

  The present inventor examined the resin member used for laser welding and found that PTT is a resin excellent in laser permeability and moldability, although it is slightly different in structure from PET and PBT. I found. The present invention has been completed based on these findings.

  The laser welding resin composition of the present invention substantially contains only polytrimethylene terephthalate (PTT) as a resin component. In the present invention, the resin component means a polymer contained in the composition. In the present invention, “substantially containing only polytrimethylene terephthalate (PTT)” includes other components that are inevitably produced in a manufacturing process and other components that are inevitably mixed in. It means that it may be. However, considering the influence on the product, it is desirable that the amount of the resin component other than PTT is as small as possible. Specifically, when the total amount of resin components is 100, it is preferably 1 wt% or less, more preferably 0.5 wt% or less, further preferably 0.1 wt% or less, particularly preferably 0.05 wt% or less, and detection. Most preferably, it is below the limit.

  PTT is a resin that can be synthesized using 1,3-trimethylene glycol and terephthalic acid as raw materials. When laminating a laser-transmissible resin and a laser-absorbing resin and melting and welding these interfaces, the use of PTT as a resin member on the laser-transmission side realizes excellent laser transmissivity and resin molding The moldability of the product can be improved.

  When the content of PTT is high, the excellent characteristics inherent in PTT are more greatly expressed. Specifically, the properties of the molded product such as tensile strength, elongation at break, bending strength and bending elastic modulus are improved. Furthermore, the transmittance, which is a characteristic strongly required for laser welding, is improved.

  In addition, when using a resin consisting essentially of a single component (PTT), it is possible to reduce the number of manufacturing steps and improve productivity compared to the case where a resin consisting of a plurality of components is used. it can. Furthermore, it is possible to reduce the number of apparatuses required for the manufacturing process using a multi-component resin, which contributes to reduction in manufacturing cost.

  Examples of the additive include mineral-based reinforcing materials, flame retardants, and tougheners.

  A mineral-type reinforcement means the compound containing a mineral component added in order to improve the mechanical strength of a resin member. In consideration of laser transmittance, it is preferable to add a mineral-based reinforcing material having a small mineral content. Examples of the mineral reinforcing material include various fibrous reinforcing materials such as glass fiber, ceramic fiber, and carbon fiber, and fibrous and / or powdered reinforcing materials such as talc, kaolin, mica, and wollastonite. These may be used alone or in combination. By blending such a mineral reinforcing material containing a mineral, effects such as improving the moldability, mechanical strength and heat resistance of the resin member can be obtained. From the viewpoint of maximizing the effect of increasing the degree of freedom in blending other components, the mineral reinforcing material to be blended is preferably glass fiber. Although the compounding quantity of a mineral type reinforcing material is not specifically limited, Preferably it is 0.1-60 wt% with respect to the total amount of a resin composition.

  A flame retardant is mix | blended in order to improve the flame retardance of a resin member. Although the compounding quantity of a flame retardant is not specifically limited, When the effect by the mixing | blending of a flame retardant and the influence which it has on laser transmittance are considered, it is preferable to contain a 0.1-30 wt% flame retardant.

  The toughener is a compound added to improve the impact resistance of the resin member under various environments. The amount of toughener blended is not particularly limited, but it is preferable to include 0.1 to 30 wt% toughener in consideration of the effect of blending toughener and the effect on laser transmission.

  The total amount of the mineral reinforcing material, flame retardant, and toughener additive described above is 0.1 to 70% by weight, preferably 0.1 to 70% by weight based on the total weight of the composition of the present invention. 50% by weight.

  The laser welding resin composition of the present invention can be added with other components at an arbitrary ratio as long as the effects of the present invention are not impaired. For example, other additives such as flame retardant aids, antioxidants, fillers, viscosity modifiers, mold release agents, nucleating agents, plasticizers, mold release agents, colorants and UV stabilizers may be blended. Good. For example, a commercially available lubricant such as LICOWAX OP is blended as a release agent. By blending the release agent, the molded product can be easily taken out from the mold during molding. The total amount of these additives (excluding mineral reinforcements, flame retardants, and tougheners) is 0.01 to 15% by weight, preferably 0.01, based on the total weight of the composition of the present invention. -10% by weight.

  The colorant preferably absorbs a visible light region (400 nm to 700 nm) and has transmission characteristics in a diode laser to YAG laser region (800 nm to 1200 nm). In particular, black colorants that are commonly used are preferably those having such characteristics.

  The black colorant for laser transmission is preferably a monoazo metal-based, anthraquinone-based, perinone-based, or quinophthalone-based dye or pigment. They can be used alone or in combination with other colorants.

  The composition of the present invention can be obtained by blending raw materials by any blending method. These blending components are usually preferably homogenized as much as possible. Specifically, the resin composition can be obtained, for example, by mixing and homogenizing all raw materials with a blender such as a blender, kneader, Banbury mixer, roll, single screw or twin screw extruder. Alternatively, the resin composition can be obtained by mixing a part of raw materials with a mixer and then adding the remaining components and further mixing to homogenize. Alternatively, the resin composition can be obtained as pellets by preliminarily dry-blending raw materials that are melt-kneaded with a heated extruder and homogenized, then extruded into a wire shape, and then cut into a desired length.

  In addition, when the laser welding resin composition of the present invention is molded as a laser welding member, it can be used as a material for a laser transmission side member, as well as by appropriately adding a laser absorption material, etc. It can also be used as a material for members.

(Laser welding method)
Next, the laser welding method of the present invention will be described.

  The laser welding method of the present invention comprises a step of preparing a laser transmissive first resin member containing substantially only polytrimethylene terephthalate as a resin component, and a laser absorbing second resin member containing a thermoplastic resin. Preparing, superimposing the first resin member and the second resin member, transmitting the laser through the first resin member, irradiating the second resin member with the first resin member, Welding the second resin member.

  The laser-transmissive first resin member is composed of the above-described resin composition of the present invention. Since the description about this resin composition is as having already demonstrated, it abbreviate | omits here. On the other hand, as the thermoplastic resin contained in the laser-absorbing second resin member, a resin that can be used for the laser welding composition can be used. Preferably, a resin having a relatively high thermal conductivity is used.

  In the present invention, a thermoplastic resin such as polyolefin, polyester or polyacetal can be particularly preferably used. These thermoplastic resins are not particularly limited as long as they can be used for laser welding.

  More specific examples of these thermoplastic resins include, for example, polypropylene and polyethylene as polyolefins. Polyester includes aliphatic polyester and aromatic polyester. For example, examples of the aliphatic polyester are poly ε-caprolactone, polylactic acid, polybutylene succinate, and polyethylene succinate, and examples of the aromatic polyester are polyethylene terephthalate and polybutylene terephthalate. Examples of polyacetals include polyoxymethylene. Of course, PTT may also be used for the second resin member.

  A thermoplastic resin having a low melting point can be used. When the melting point is low, the melting is performed with a small amount of laser energy, so that the effect of shortening the cycle and reducing the cost by the low-power laser device can be obtained.

  These thermoplastic resins are contained in an amount of 40 to 100% by weight, preferably 60 to 100% by weight, based on the total weight of the laser-absorbing second resin member of the present invention.

  As other components of the laser-absorbing second resin member, various additives can be included as in the case of the laser-transmitting first resin member composition. The additive amount of these additives is 0.01 to 15% by weight, preferably 0.01 to 10% by weight, based on the total weight of the second resin member.

  As described above, the laser welding method of the present invention includes a step of preparing a laser-transmissive first resin member, a step of preparing a laser-absorbing second resin member, the first resin member, and the second resin member. A step of superimposing the resin member, and a step of welding the first resin member and the second resin member through the first resin member and irradiating the second resin member with a laser. .

  In carrying out the laser welding method of the present invention, the preparatory stage for the first and second resin members is performed by molding the respective compositions. This molding can be performed by various commonly performed means. For example, it can be molded by an injection molding machine using pellets of each composition used for the first resin member having laser permeability and the second resin member having laser absorption. In the present invention, injection molding is preferred, but any generally employed molding method such as extrusion molding, compression molding, foam molding, blow molding, vacuum molding, injection blow molding, rotational molding, calendar molding, solution casting, etc. is adopted. You can also. By such molding, various shapes of laser welding resin members can be obtained.

  Next, the first and second resin compositions molded in this manner are overlapped, transmitted through the first resin member, and irradiated with a laser to the second resin member, so that the first resin member and the second resin member The step of welding is described.

  FIG. 1 is a schematic view showing a general example of the laser welding method of the present invention. Referring to FIG. 1, a first resin member 2 and a second resin member 3 including a surface 4 are provided. In a typical laser welding method, the first resin member 2 “transmits” the laser beam 1, that is, the first resin member 2 has a high transmittance with respect to the laser beam 1, and the second resin member 3 has the laser beam 1. The second resin member 3 has a high absorptance with respect to the laser beam 1. Accordingly, when the laser beam 1 is directed to the first resin member 2 and the second resin member 3 that are bonded on the surface 4, the laser beam 1 passes through the first resin member 2 and reaches the second resin member 3. The second resin member 3 and its surface 4 absorb the energy of the laser beam 1, thereby melting the surface 4, and when the surface 4 is pressed against the first resin member 2, the first resin member 2 and the second resin member 2 As a result, the resin members 3 are welded together.

  In FIG. 1, when the laser 1 is irradiated toward the surface 4, the irradiation speed varies depending on the material to be welded. For example, when PTT is used for the laser transmissive resin member, the irradiation speed is 0.1. Scan speeds in the range of ~ 100 cm / sec can be used. The laser output varies depending on the material to be welded. For example, when Crustin (registered trademark) SK605 BK851 is used as the laser-absorbing resin member, an output in the range of 10 to 250 W may be used. it can.

  In addition, although linear welding was demonstrated in FIG. 1, this method is not limited to this, Welding of various shapes is possible. In addition, the members to be welded (the first resin member and the second resin member) do not have to have the shape as shown in FIG. 1, and have various forms such as a circular shape, a cylindrical shape, and a hemispherical shape depending on the application. It can take. Further, these members may have the same or different thicknesses, and a step may be provided for each of the members, and the stepped portions may be brought into contact with each other to irradiate the laser.

  Moreover, as a laser irradiation aspect, you may scan by moving a laser irradiation part (not shown), and operate the base (not shown) to which the resin member is fixed according to a scan. It may be.

  Laser light sources that can be used in the laser welding of the present invention include a YAG laser (1064 nm), a semiconductor laser (for example, those having wavelengths in the near infrared region such as 808 nm, 940 nm, and 980 nm).

(Resin molded product)
Furthermore, the resin molded product of the present invention will be described. The resin molded product of the present invention includes a first resin member of a laser transmissive first resin member containing substantially only polytrimethylene terephthalate as a resin component, and a laser absorptivity laser-welded to the first resin member. Second resin member.

  The resin molded product of the present invention can be a substantial product. For example, it is useful for electrical / electronic applications, automotive applications, general miscellaneous goods applications, building materials, and the like. In particular, the present invention can be used for cockpit module parts used for automobile parts, for example, module parts in engine rooms, intake manifolds, underhood parts, radiator parts, instrument panels, and the like. Other uses are useful for electronic parts such as personal computers, liquid crystal projectors, mobile devices, and mobile phones.

In the examples, the following materials were used as PBT, PTT, lubricant, and glass fiber.
PBT: CRASTIN 6134
PTT: Sorona (registered trademark) Bright
Mold release lubricant: LICOWAX OP
Glass fiber: CS 03 JA FT 689S

(Reference Example 1)
The PTT and the lubricant were premixed before adding the glass fibers so that the lubricant was uniformly dispersed. These mixtures were melted and kneaded with a twin screw extruder (ZSK-40 manufactured by Z & P). When the mixture was melted, glass fibers were added to finally obtain pellets. This composition is shown in Table 1.

  Using the obtained pellets, on an injection molding machine (J100EII-P manufactured by JSW), (a) a 4 mm thick test piece based on ISO, (b) a 1 mm thick flat plate, and (c) a 2 mm thick flat plate Molded. The resin melting temperature at this time was 260 to 270 ° C., and the mold temperature was 80 ° C.

  Based on the measurement method by ISO, the tensile strength, bending at break, bending strength, and bending elastic modulus were measured with an ISO test piece. The transmittance of the 1 mm and 2 mm thick molded flat plates was measured in the near infrared region of 400 nm to 1200 nm with a spectrometer (UV-3100, manufactured by Shimadzu Corporation). Table 1 shows the transmittance at a wavelength of 940 nm which is usually used in a diode laser. Table 1 summarizes all the results.

(Examples 2-7, Comparative Example 1)
A resin molded product was obtained by the same procedure as in Reference Example 1 except that the blending amounts of the components were changed to the amounts shown in Table 1.

  The results obtained by Reference Example 1, Examples 2-7 and Comparative Example 1 are shown in FIGS. FIG. 2 is a graph showing the relationship between the PTT content, tensile strength, and elongation at break. FIG. 3 is a graph showing the relationship between the PTT content, flexural strength, and flexural modulus. FIG. 4 is a graph showing the relationship between the PTT content and the transmittance.

  As shown in the figure, when the content of PTT in the resin component is increased, the elongation at break hardly changes, but the tensile strength, the bending strength, the bending elastic modulus, and the transmittance are improved all over.

  The present invention can be applied to the production of a resin molded product by laser welding.

DESCRIPTION OF SYMBOLS 1 Laser beam 2 1st resin member 3 2nd resin member 4 Surface

Claims (3)

  A resin component composed of polytrimethylene terephthalate and polybutylene terephthalate is included, and the content of polytrimethylene terephthalate is 14.33 to 85.96% by weight based on the total weight of the resin component. Laser welding resin composition. A resin component composed of polytrimethylene terephthalate and polybutylene terephthalate, wherein the content of polytrimethylene terephthalate is 14.33 to 85.96% by weight based on the total weight of the resin component. 1 preparing a resin member;
Preparing a laser-absorbing second resin member containing a thermoplastic resin;
Superposing the first resin member and the second resin member;
Passing through the first resin member, irradiating the second resin member with a laser, and welding the first resin member and the second resin member;
Including laser welding method. A resin component composed of polytrimethylene terephthalate and polybutylene terephthalate, wherein the content of polytrimethylene terephthalate is 14.33 to 85.96% by weight based on the total weight of the resin component. 1 resin member;
A laser-absorbing second resin member laser-welded to the first resin member;
A resin molded product.

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