JP2008031393A - Laser ray transmitting colored resin composition and related art - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser ray transmitting colored resin composition excellent in molding accuracy, good in molded product appearance and gloss, capable of preventing or effectively reducing the gap between the materials to be welded in the case of a molded product used for laser welding, and good in heat resistance and fastness, and to provide the laser ray transmitting material excellent in dimension stability and shape stability and capable of preventing or effectively reducing the gap between the materials to be welded when used for laser welding. <P>SOLUTION: The laser ray transmitting colored resin composition comprises a polyphenylene sulfide resin and a colorant having an endothermic peak between 200°C and 300°C as determined by TG/DTA thermal analysis, wherein the difference T<SB>C</SB>-T<SB>N</SB>between the crystallization point T<SB>C</SB>of the laser ray transmitting colored resin composition and the crystallization point TN of the same composition as the composition except for not containing the aforementioned colorant, is not less than 0°C as determined by DSC thermal analysis. The laser ray transmitting material is made of the laser ray transmitting colored resin composition, and has one exothermic energy peak and one endothermic energy peak as determined by DSC thermal analysis. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laser light transmissive colored resin composition, a laser light transmissive member comprising the resin composition, a laser light transmissive colored resin composition for forming a laser light transmissive member, a method for producing a laser light transmissive member, and a laser. The present invention relates to a laser beam transmitting member for welding and a method for manufacturing a laser welded body.

  As a method for joining members made of thermoplastic synthetic resin, a method by laser welding is known. Such laser welding is performed as follows, for example. One member exhibiting laser light permeability is brought into contact with the other member exhibiting laser light absorption. When laser light is irradiated from the side of the laser light transmitting member to the contact portion of both members, the laser light absorbing member absorbs the laser light transmitted through the laser light transmitting member. Generates heat. With this heat, the laser light absorbing member is melted around the portion that has absorbed the laser light, and the laser light transmitting member that is in contact with the portion is melted, and both members are fused at the contact portion. When the molten resin is solidified due to the temperature drop, the laser light transmitting member and the laser light absorbing member are bonded with sufficient welding strength.

  The features of this laser welding are that it can be welded without bringing the laser light generating part into contact with the part to be welded, and because it is a local heating, the thermal effect on the peripheral part is negligible. That there is no risk of mechanical vibration, that it is possible to weld members having fine parts and complex three-dimensional structures, that reproducibility is high, that high airtightness can be maintained, that the welding strength is high, For example, it is difficult to visually recognize the boundary, and dust is not generated. In addition, reliable welding can be performed with simple operations, and fastening with fastening parts (bolts, screws, clips, etc.), which is a conventional method for joining resin members, bonding with adhesives, vibration welding, ultrasonic welding A welding strength equal to or better than that of the above method can be obtained. However, since there is little influence of vibration and heat, it is possible to realize labor saving, improvement of productivity, reduction of production cost, and the like.

  Therefore, laser welding is suitable for joining functional parts and electronic parts that should avoid the effects of vibration and heat, for example, in the automobile industry, electrical / electronic industry, etc., and also suitable for joining resin parts with complex shapes. It is possible to use.

  As a technique related to laser welding, for example, there is an attempt as described in JP-A-11-170371 (Patent Document 1). This is because the laser beam is focused so that the opaque member made of a material that absorbs laser light and a thermoplastic synthetic resin and the colorless transparent member made of a thermoplastic synthetic resin that transmits the laser beam are in contact with each other. It is a laser welding method which has the process of irradiating. However, in this case, since the member that transmits the laser beam is colorless and transparent, when viewed from the laser beam transmitting member side, the welded portion is different in color and smoothness from the non-welded portion, and the appearance is good. It can not be said.

  In addition, when joining the part where the laser beam transmitting member and the laser beam absorbing member are in contact by laser welding, it is extremely important to manage the gap that can exist at the contact point within a sufficiently small range. It is.

  Therefore, when laser welding is used as a joining means at an actual production site, as a countermeasure against gaps that may exist between members to be joined, welding is mainly performed with the gaps reduced by pressurization with an air clamp or the like. It is. As for such a gap reduction means by pressurization, for example, Japanese Patent Application Laid-Open No. 63-118237 (Patent Document 2) relating to a manufacturing method of a laminated structure, and Japanese Patent Application Laid-Open No. 2002-337236 (Patent Document 2) relating to a welding method of resin members. Document 3), Japanese Patent Application Laid-Open No. 2004-66739 (Patent Document 4) and the like related to a laser welding method and a laser welding apparatus.

However, the gap reduction means by pressurization includes an increase in production cost and a decrease in productivity (for example, tact time) due to the cost of introducing a pressurization facility such as an air clamp and the time required to set up the target member for laser welding in the pressurization facility There has been a problem of accompanying problems such as time extension.
JP-A-11-170371 JP-A-63-118237 JP 2002-337236 A JP 2004-66739 A

  The present invention has been made in view of the above-described problems existing in the prior art, and the object thereof is excellent in molding accuracy, good appearance and gloss of the molded product, When used for laser welding, the gap between the members to be welded can be prevented or effectively reduced, and the laser light-transmitting colored resin composition with good heat resistance and fastness, dimensional stability and shape stability Laser beam transmitting member capable of preventing or effectively reducing a gap between members to be welded when used for laser welding, and a method for producing a laser beam transmitting member using the resin composition Another object of the present invention is to provide a method for producing a laser welded body using the laser light transmitting member.

The laser light transmitting colored resin composition of the present invention that achieves the above-mentioned object is
A laser light transmitting colored resin composition containing at least a polyphenylene sulfide resin and a colorant, wherein the colorant has an endothermic peak between 200 ° C. and 300 ° C. in a TG / DTA thermal analysis. In the DSC thermal analysis, the crystallization point T _C of the laser light transmitting colored resin composition is the same as the laser light transmitting colored resin composition except that it does not contain the colorant. is the difference between the _{N T} C -T _N, characterized in that at 0 ℃ or higher.

  The laser light transmitting member of the present invention is made of the laser light transmitting colored resin composition, and has one exothermic energy peak and one endothermic energy peak in DSC thermal analysis.

  The laser light transmitting colored resin composition for forming a laser light transmitting member of the present invention is composed of the laser light transmitting colored resin composition.

  Further, the laser light transmissive member manufacturing method of the present invention is such that the laser light transmissive colored resin composition is molded so as to have one exothermic energy peak and one endothermic energy peak in DSC thermal analysis. Become.

  The laser welding member for laser welding of the present invention comprises the laser beam transmitting colored resin composition and has one each of exothermic energy peak and endothermic energy peak in DSC thermal analysis.

Further, in the method for producing a laser welded body of the present invention, in the state where the laser light transmitting member and the laser light absorbing member are substantially in contact with each other, the laser light for laser welding is transmitted through the laser light transmitting member. By irradiating the laser light absorbing member so as to be absorbed, the contact portion between the two members is welded.
In this manufacturing method, for example, it is possible to laser-weld the laser-welding member for laser welding of the present invention from a plurality of directions to one laser-absorbing member.
In addition, another method for producing a laser welded body of the present invention is as follows.
A method of manufacturing a welded body by welding one member and the other member,
The one member is the laser light transmitting member,
In a state where the one member and the other member are substantially brought into contact with each other via a laser light absorbing thin layer, the laser light absorbing laser beam is transmitted through the laser light transmitting member. By irradiating so that the thin layer absorbs, the two members are welded through the laser light absorbing thin layer.
In this case, the thin layer for absorbing laser light may be formed by a member independent of the two members, or may be formed on one or both of the two members.

  When the laser light transmitting colored resin composition of the present invention is excellent in molding accuracy, the appearance and gloss of the molded product can be good, and the laser light transmitting colored member which is the molded product is used for laser welding. In addition, the gap between the member to be welded can be prevented or effectively reduced, and by being colored, laser welding with the laser light absorbing member from the side of the laser light transmitting member that is a molded product It is difficult to visually recognize the part, and heat resistance and fastness are also good.

  Further, the laser light transmissive member of the present invention is excellent in dimensional stability and shape stability, and when used for laser welding, can prevent or effectively reduce the gap between the member to be welded. It is possible to obtain a good quality laser welded body having a stable tensile strength. According to the laser welded body manufacturing method of the present invention, by using the laser light transmitting member of the present invention, the gap between the member to be welded can be prevented or effectively reduced. It is possible to obtain a stable and good quality laser welded body. A simple laser device can also be used.

The laser light transmitting colored resin composition of the present invention contains at least a polyphenylene sulfide resin (“PPS resin” in the following description means a polyphenylene sulfide resin) and a colorant.
The laser light transmitting colored resin composition of the present invention may be substantially composed of a PPS resin and a colorant.

  The colorant used in the resin composition of the present invention needs to have an endothermic peak between 200 ° C. and 300 ° C. in the TG / DTA thermal analysis. More specifically, it is a colorant having a substantial endothermic peak only between 200 ° C. and 300 ° C. in the TG / DTA thermal analysis in which the temperature is raised from 30 ° C. to 550 ° C.

  In the TG / DTA thermal analysis for this colorant, it is possible to employ a measurement condition in which the temperature is raised from 30 ° C. to 550 ° C. at a rate of 10 ° C./min in an air (air) atmosphere of 200 ml / min. . Moreover, as a TG / DTA measuring device, SII EXSTAR6000 (brand name) by Seiko Instruments Inc. can be used.

Further, the resin composition of the present invention is the same as the laser light transmitting colored resin composition except that the crystallization point in DSC thermal analysis is T _C and does not contain the colorant (resin or resin composition). the crystallization point of the DSC thermal analysis in the case of the T _N of, it is necessary that a difference between T _C -T _N is 0 ℃ or higher. Needless to say, both crystallization points should be measured under the same conditions.

  In this DSC thermal analysis, it is possible to employ a measurement condition in which the temperature is increased from 30 ° C. to 330 ° C. at a rate of 10 ° C./min, and then the temperature is decreased from 330 ° C. to 30 ° C. at a rate of 10 ° C./min. . Moreover, as a DSC measuring instrument, SII EXSTAR6000 (trade name) manufactured by Seiko Instruments Inc. can be used.

Obtained by satisfying the above-mentioned resin composition is T _C -T _N is 0 ℃ or more, molded articles made of the resin composition (e.g., molded product obtained by injection molding) by bending deformation (molding that can occur Curvature deformation of the obtained molded product when the molded product to be used as a reference can be effectively suppressed. Therefore, when using a laser beam transmitting member made of the resin composition of the present invention for laser welding with a laser beam absorbing member, the gap between the two members can be prevented or effectively reduced. The welding quality of the laser welded body becomes stable.
Note that the TC-TN, preferably 30 ℃ ≧ TC-TN ≧ 5 ℃, more preferably _{20 ℃ ≧ T C -T N ≧} 10 ℃. As a result, a laser light transmissive member with high molding accuracy can be obtained.

  The laser light transmissive member of the present invention is composed of the laser light transmissive colored resin composition, and it is necessary to have one exothermic energy peak and one endothermic energy peak in DSC thermal analysis. More specifically, in DSC thermal analysis in which the temperature is raised from 30 ° C. to 330 ° C. and then lowered from 330 ° C. to 30 ° C., substantially only one peak of exothermic energy and one endothermic energy peak are included. is required.

  In this DSC thermal analysis, it is possible to employ a measurement condition in which the temperature is increased from 30 ° C. to 330 ° C. at a rate of 10 ° C./min, and then the temperature is decreased from 330 ° C. to 30 ° C. at a rate of 10 ° C./min. . Moreover, as a DSC measuring instrument, SII EXSTAR6000 (trade name) manufactured by Seiko Instruments Inc. can be used.

  PPS resin has a relatively low crystallization rate among engineering plastics. Therefore, when a PPS resin is molded using a mold, the mold temperature is usually set high (usually 150 ° C.) in order to complete crystallization of the resin.

  If the mold temperature is set low in the molding of the PPS resin, the molten resin in the mold is rapidly cooled, so that the obtained molded product has a part where the crystallization is complete and a part where the crystallization is incomplete. In the molded product, the crystallinity varies. When DSC measurement is performed on such a molded product, a portion of incomplete crystallization is crystallized in the measurement process, and thus a peak of exothermic energy called a recrystallization point appears. When a recrystallization point (exothermic energy peak) appears before reaching the melting point (endothermic energy peak) at the time of temperature rise in DSC measurement, the crystallization state of the PPS resin molded product is unstable, and dimensional stability It can be judged that the property and shape stability are poor.

  The laser light transmitting member of the present invention is obtained by molding the laser light transmitting colored resin composition of the present invention so as to have one each of an exothermic energy peak and an endothermic energy peak in DSC thermal analysis. It is done.

  A molded product obtained by injection molding a PPS resin not containing a colorant has a recrystallization point even when the molding die temperature is 130 ° C. The setting of the mold temperature for obtaining a molded product having no recrystallization point by injection molding a PPS resin not containing a colorant is preferably around 150 ° C. However, since the resin composition of the present invention contains the colorant, a molded product having no recrystallization point can be obtained even when injection molding is performed at a mold temperature of 130 ° C. That is, it is possible to obtain a colored molded article having good dimensional stability and shape stability while setting the mold temperature low to reduce the production cost.

  More specifically, the laser light transmitting member of the present invention has a warp amount of 0.5 mm or less, more preferably 0.2 mm or less. The term “the amount of warp” in the present specification refers to molding with a mold having a rectangular parallelepiped shape with a length of 80 mm × width of 50 mm × thickness of 1 mm, and a molded product is obtained. When the front and back surfaces of each are placed on a horizontal plane and each corner is pressed with a weight of 100 g, the maximum value of the height at which the diagonal rises from the horizontal plane.

  The laser light transmitting member of the present invention has excellent molding accuracy, and the appearance and surface gloss of the obtained member are good. In this respect, if the laser light transmitting member of the present invention is further specified, it is preferable that the glossiness is 100 or more under the measurement condition of a luminous flux of 60 degrees. When the glossiness of the laser light transmitting member under the measurement condition of the light flux of 60 degrees is 100 or more, the surface smoothness is high. Therefore, when the laser light transmitting member is overlapped with the laser light absorbing member, Even if a gap occurs, the influence of the gap on laser welding is reduced, and the welding quality can be further stabilized.

As the colorant having an endothermic peak between 200 ° C. and 300 ° C. in the above TG / DTA thermal analysis, one or two dyes having transparency in the wavelength range of laser light (wavelength of 800 nm to 1600 nm) are used. A mixture of the above (which may or may not overlap the visible light absorption range) can be used in combination. In the case of a colored resin composition containing a colorant having an endothermic peak between 200 ° C. and 300 ° C. and a PPS resin, the colorant is uniformly present in the resin at a temperature near the melting point of the PPS resin (melting point in DSC measurement). scatter. Therefore, when molding a colored resin composition containing such a colorant and a PPS resin, if the mold temperature is 130 ° C. to 150 ° C., the colored resin molded product is relatively uniform.
On the other hand, colorants having an endothermic peak at 200 ° C. or lower often have various colorant decomposition products. When injection molding of a colored resin composition containing such a colorant and a PPS resin is performed, even if the mold temperature is 150 ° C., crystallization proceeds partially early or delayed. Therefore, the obtained colored resin molded product has an incompletely crystallized portion, and a recrystallization point appears by DSC measurement. The crystal size is also non-uniform.
The structure is not particularly limited as long as it is a colorant having transparency to one or two or more kinds of laser beams having a specific wavelength used for laser welding. Specifically, azo, azo metal-containing, azomethine, anthraquinone, quinacridone, dioxazine, diketopyrrolopyrrole, anthrapyridone, isoindolinone, indanthrone, perinone, perylene And various organic dyes such as indigo, thioindigo, quinophthalone, quinoline, and triphenylmethane. An organic dye is preferable in terms of compatibility with the PPS resin.

As an example of a colorant in which two or more kinds of colorants are mixed, green (for example, a combination of blue and yellow) can be obtained by combining blue, purple, and green anthraquinone dyes with yellow and / or red colorants. ), Purple (for example, a combination of blue + red), black (for example, a combination of blue + yellow + red, or a combination of purple + yellow) and the like showing various hues. Examples of black colorants that are important in industrial applications include anthraquinone blue dyes, black colorants that combine red and yellow colorants of other structures, and anthraquinone green dyes and red colors of other structures. A black colorant combined with an agent can be mentioned. Preferred red colorants in these examples include azo red dyes, perinone red dyes, and anthrapyridone red dyes.
As a commercial product of such a colorant, a laser light transmitting colorant trade name “eBIND LTW-8400C” (“eBIND” and “LTW” are registered trademarks) manufactured by Orient Chemical Co., Ltd. It is done.

  The content of the colorant in the laser light transmitting colored resin composition of the present invention is preferably 0.01 to 10% by weight with respect to the PPS resin. More preferably, it is 0.03 to 5% by weight, and still more preferably 0.05 to 1% by weight.

Examples of the laser light source used in the present invention include a solid-state laser (Nd-YAG, YVO ₄ , RUBY), a semiconductor laser, a tunable laser, and a titanium sapphire laser. Among these, a laser having an oscillation wavelength in the range of 800 to 1600 nm, which is longer than visible light, can be preferably used. A laser having an oscillation wavelength of 800 to 1100 nm is more preferable. In addition, a halogen lamp or a xenon lamp that generates infrared rays having a wavelength of 700 nm or more may be used as the light source.

In the laser light-transmitting colored resin composition of the present invention, the T- _{color resin} that is the transmittance of laser light having a wavelength of 940 nm and the same as the laser light-transmitting colored resin composition except that it does not contain a colorant T _{colored resin} / T _{non-colored resin,} which is the ratio of the T _{uncolored resin} is a transmittance of laser light having a wavelength of 940nm is preferably 0.5 or more. More preferably, it is 0.7 to 1.1, and still more preferably 0.8 to 1.1.

  The PPS resin is a polymer mainly composed of a repeating unit composed of a thiophenylene group represented by (-φ-S-) [φ is a substituted or unsubstituted phenylene group]. This resin can be obtained by polymerizing a monomer synthesized by reacting paradichlorobenzene and alkali sulfide under high temperature and high pressure. This resin is of two types: a linear type that has a desired degree of polymerization only by a polymerization step using a polymerization aid, and a crosslinked type that is obtained by thermally crosslinking a low molecular weight polymer in the presence of oxygen. Roughly classified. In particular, a straight-chain type is suitable for the present invention because it is excellent in laser light transmittance. A polymer alloy can be used as the PPS resin in the present invention. Examples include PPS / polyolefin alloys, PPS / polyamide alloys, PPS / polyester alloys, PPS / polycarbonate alloys, PPS / polyphenylene ether alloys, PPS / liquid crystal polymer alloys, PPS / polyimide alloys, PPS. / Polysulfone-based alloys. Further, the melt viscosity of the PPS resin is not particularly limited as long as it can be melt kneaded. However, a melt viscosity in the range of 5 to 2000 Pa · s can usually be used, and a melt viscosity in the range of 100 to 600 Pa · s can be used. preferable. The PPS resin as described above has characteristics suitable for applications such as electronic parts and automobile parts.

  The colored resin composition of the present invention may contain appropriate amounts of various reinforcing materials depending on the application and purpose. As this reinforcing material, what can be used for the reinforcement | strengthening of a normal synthetic resin can be used, and it does not specifically limit.

  Preferred examples of the reinforcing material include glass fibers, carbon fibers, other inorganic fibers, and organic fibers (such as aramid, nylon, polyester, and liquid crystal polymer). Glass fiber is preferable for reinforcing the colored resin composition of the present invention, which requires laser light transmission. The fiber length of the glass fiber that can be suitably used is 2 to 15 mm, and the fiber diameter is 1 to 20 μm. There is no restriction | limiting in particular about the form of glass fiber, For example, any, such as roving and a milled fiber, may be sufficient. These glass fibers can be used alone or in combination of two or more. The content is preferably 5 to 120 parts by weight with respect to 100 parts by weight of the PPS resin. When the amount is less than 5 parts by weight, it is difficult to obtain a sufficient glass fiber reinforcing effect. When the amount exceeds 120 parts by weight, the formability tends to be lowered. Further, when the purpose is joining by laser welding, in principle, the resins are melt-bonded to each other, so that the welding strength is higher when the glass fiber content is smaller. The glass fiber content considering this point is preferably 10 to 60 parts by weight, particularly preferably 20 to 50 parts by weight.

  Other reinforcing materials include platy fillers such as mica, sericite, and glass flake, silicates such as talc, kaolin, clay, wollastonite, bentonite, and alumina silicate, alumina, silicon oxide, magnesium oxide, and oxide. Particulate packing of metal oxides such as zirconium and titanium oxide, carbonates such as calcium carbonate, magnesium carbonate and dolomite, sulfates such as calcium sulfate and barium sulfate, glass beads, ceramic beads, boron nitride and silicon carbide Materials etc. can be added.

  The colored resin composition of the present invention can contain various additives as required. Examples of such additives include auxiliary colorants, dispersants, stabilizers, plasticizers, modifiers, ultraviolet absorbers or light stabilizers, antioxidants, antistatic agents, lubricants, mold release agents, crystals. Examples thereof include accelerators, crystal nucleating agents, flame retardants, and elastomers for improving impact resistance.

  The colored resin 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, for example, all raw materials can be obtained by mixing and homogenizing with a mixer such as a blender, kneader, Banbury mixer, roll, or extruder. For example, after mixing a part of raw materials with a mixer, it can be obtained by adding the remaining components and further mixing and homogenizing. Alternatively, for example, a raw material that has been dry blended in advance can be melt-kneaded with a heated extruder, homogenized, extruded into a wire shape, and then cut into a desired length to obtain colored pellets that form colored granules. .

  The colored resin composition of the present invention can also be prepared by further diluting a master batch containing the colorant at a high concentration in the PPS resin with the PPS resin. By using the master batch, a colored resin composition in which the colorant is favorably dispersed can be obtained. The master batch can be obtained by any method. For example, after mixing the powder or pellets of resin as the base of the masterbatch and the colorant with a mixer such as a tumbler or super mixer, the mixture is heated and melted into pellets by an extruder, batch kneader or roll kneader. Alternatively, it can be obtained by coarsening. For example, after adding a coloring agent to the resin for master batches which is still in a solution state after synthesis, a master batch can be obtained by removing the solvent.

  Molding of the colored resin composition of the present invention can be performed by various commonly performed procedures. For example, it can carry out by shape | molding with processing machines, such as an extruder, an injection molding machine, and a roll mill, using the colored resin pellet which consists of a colored resin composition of this invention. Further, PPS resin pellets or powder, pulverized colorant, and various additives as necessary may be mixed in a suitable mixer, and the mixture may be molded using a processing machine. . Further, for example, a colorant may be added to a monomer containing an appropriate polymerization catalyst, and this mixture may be polymerized to obtain a desired PPS resin, which may be molded by an appropriate method. As a molding method, for example, any generally used molding method such as injection molding, extrusion molding, compression molding, foam molding, blow molding, vacuum molding, injection blow molding, rotational molding, calendar molding, solution casting, etc. should be adopted. You can also. By such molding, laser light transmitting members having various shapes can be obtained.

In general, the advantages of laser welding methods are that three-dimensional welding is possible, so that the degree of freedom in the shape of the mold is increased, and, unlike vibration welding, there is no burrs on the welding surface, and vibration and wear powder are improved. Is not generated, and is easily applied to electronic parts. Disadvantages include upfront investment required for laser welding equipment, generation of gaps between welding members due to sink marks after molding of the resin material, and the like. In particular, this gap problem is the biggest problem when performing welding by operating a laser welding apparatus. Therefore, the actual situation is that a pressing jig is uniquely created according to the shape of the welding member, and welding is performed in a state in which the object to be welded is pressed by an air clamp or the like to eliminate or reduce the gap.
In contrast, the laser light transmitting member of the present invention has high molding accuracy and a small amount of warpage. Therefore, in laser welding using the laser light transmissive member of the present invention, it is prevented that the gap between the two members at the contact point between the laser light transmissive member and the laser light absorbent member is increased by warpage, Laser welding can be performed with a relatively simple apparatus with little need for clearance reduction by an air clam or the like. The gap between the two members is preferably 0 to 0.05 mm.

  Examples of the laser welding apparatus include a scanning type in which the laser beam irradiation unit moves, a masking type in which the welding member moves, a type in which laser beam is simultaneously irradiated onto the welding member from various directions, and the automobile industry is paying attention. The method is a scanning type, and at present, a numerical value of, for example, 5 m / min is used as the reference for the production tact time as the scanning speed.

  In principle, laser welding uses conversion of laser light energy to thermal energy, so that the welding performance is significantly affected by the welding conditions. In general, the amount of heat that the irradiated laser beam receives on the surface of the absorbing member can be calculated by the following equation.

Surface heat quantity of absorbing member (J / mm ² ) = (Laser beam output (W) × Laser beam transmissivity (%) × 1/100) / (Laser beam spot diameter (mm) × Laser beam) Scanning speed (mm / sec)) ... (I)

As can be seen from equation (I), in order to increase production efficiency in laser welding, it is required to use a high-power type laser welding apparatus and increase the scanning speed. In the case of a material excellent in laser light transmission obtained from a polyamide resin, the production efficiency can be improved by such means.
However, in laser welding using PPS resin, the size of the part itself is not so large for the purpose of the resin, so it can not be said that high power and high speed welding conditions are desirable, rather low power and low speed are more desirable. The welding quality tends to be stable and tends to be desirable.
In the case of PPS resin, since the laser light permeability of the resin itself is not high, the rate at which the laser light is absorbed in the laser light transmitting member before reaching the surface of the laser light absorbing member is relatively high. When laser welding is performed at the output, problems such as ignition on the surface of the laser light transmitting member are likely to occur. Therefore, in laser welding of the PPS resin, for example, a glass plate is placed on the laser light transmissive member, and the heat generated by the laser light transmissive member is absorbed by the glass plate. It is important to take such measures.

  Generally, in order to increase the welding strength, it is necessary to generate a certain amount of surface heat in the laser light absorbing member. For this purpose, it is necessary to examine various conditions such as increasing the laser output, decreasing the scanning speed, and reducing the spot diameter according to the properties of the target laser light absorbing member and laser light transmitting member.

The molded member of the colored resin composition of the present invention can be welded in a non-contact manner even when a halogen lamp that generates infrared rays having a wavelength of 700 nm or more is used. In many cases, the lamp shape in this case is a band-like lamp. Examples of the irradiation mode include a scanning type in which the lamp irradiation unit moves, a masking type in which the welding member moves, and a type in which the lamp is simultaneously irradiated onto the welding member from various directions. Irradiation can be performed by appropriately adjusting the irradiation width of infrared rays, irradiation time, irradiation energy, and the like.
However, since the halogen lamp has an energy distribution centering on the near infrared region, energy may exist in the short wavelength side of the energy distribution, that is, in the visible region. In such a case, since welding marks may be formed on the surface of the member, the energy in the visible region can be blocked using a cut filter or the like.
Since many PPS resin moldings are small, such as electric and electronic parts, laser welding that can be finely controlled by setting various welding conditions is suitable for joining.

For laser welding, it is desirable to use a laser light transmitting member that transmits at least 15% of laser light in a longer wavelength region (800 to 1600 nm) than visible light used for laser welding. In addition, a laser light transmitting member having an infrared transmittance of at least 20% of one or two or more of the wavelengths of 808 nm, 840 nm, and 940 nm of the semiconductor laser and 1064 nm of the YAG laser is used. Further preferred. If the transmittance is lower than this, the laser light of these wavelengths cannot be sufficiently transmitted, so that the above-described problems may occur and the welding quality may be deteriorated.

The laser light absorbing member is preferably composed of a laser light absorbing colored resin composition (preferably a thermoplastic resin composition) using at least carbon black as a laser light absorber and black colorant. In this case, carbon black having a primary particle diameter of 18 to 30 nm is preferably used. By using such carbon black, a highly dispersed laser light absorbing member that absorbs laser light at a high absorption rate can be obtained.
Moreover, a nigrosine dye can be used with carbon black as a laser beam absorber and black colorant. By using the nigrosine dye, the laser light absorption rate can be adjusted well. Examples of nigrosine dyes include C.I. I. Nigrosine dye belonging to Solvent Black 7 is preferred. Also, as the laser light absorber and black colorant, other laser light absorbers (for example, phthalocyanine-based, cyanine-based, metal complexes, etc.) are used without using carbon black (or other laser light absorber-colored. A laser light absorbing member can also be obtained from a laser light absorbing colored resin composition (using an agent [for example, aniline black]).

  The laser light absorbing member includes a colorant other than carbon black, a laser light absorber exemplified by a phthalocyanine-based, cyanine-based, metal complex, and the like (or other laser light absorber / colorant used). It may be formed of a non-black laser-absorbing colored resin composition containing You may form with the laser beam absorptive colored resin composition containing laser beam absorbers and coloring agents other than carbon black.

The laser light absorbing member can be produced by molding a laser light absorbing colored resin composition in the same manner as the laser light transmitting member. The laser light-absorbing colored resin composition may further contain organic dyes and additives such as the above-mentioned various colorants and various dyes that can be used in the production of the laser light-transmissive member. . The material used for manufacturing the laser light absorbing member can be selected from a wide range because there is no restriction of laser light transmission compared to the material used for the laser light transmitting member. The amount of the colorant used in the laser light absorbing colored resin composition can be, for example, 0.01 to 10% by weight, preferably 0.05 to 5% by weight, based on the resin (preferably thermoplastic resin). It is.
The laser light absorbing thin layer may be, for example, a thin laser light absorbing member (for example, a film-like material), or may be formed on one or both of both members to be laser welded. It may be a thing. In the latter case, for example, it is formed by applying (or printing, etc.) and solidifying an ink or paint having laser light absorption by containing a colorant used for the laser light absorbing member. Can do.
Examples of such laser light absorbing inks include inks in which a laser light absorber is dissolved or dispersed in an organic solvent. A preferable ink composition applied to the PPS resin includes an alcohol or glycol solvent, a laser light absorbent dissolved in the solvent, and an ink composed of at least a resin dissolved in the solvent. Such laser light absorbing ink may contain additives such as a pH adjusting agent, a viscosity adjusting agent, a preservative, an antioxidant, and a light stabilizer. Nigrosine is preferred as the laser light absorber that dissolves in the organic solvent.

  Next, through a laser welded body of a laser light transmitting member made of the laser light transmitting colored resin composition of the present invention and a laser light absorbing member made of a laser light absorbing composition, or a laser light absorbing thin layer A method for manufacturing a laser welded body obtained by welding laser light transmitting members together will be described.

  The laser welded body produced by the production method of the present invention includes those obtained by laser welding once, as well as those obtained by laser welding a plurality of times. As an example of what is laser-welded a plurality of times, an example in which laser welding is performed with a laser light-absorbing member or a laser light-absorbing thin layer sandwiched between laser light-transmitting members can be given. When a laser light absorbing thin layer with a sufficiently thin laser light absorbing member is used, it can be welded by laser light irradiation from one of the laser light transmitting members. However, in the case of a relatively thick laser light absorbing member, laser light is irradiated from both laser light transmitting members sandwiching the laser light absorbing member (either simultaneously or sequentially). Possible) and laser welding.

Laser welding production process example 1 (FIG. 1)
(A) The laser beam transmitting member 1 using the laser beam transmitting colored resin composition of the present invention is molded.
(B) The welding target portions of the laser light absorbing member 2 made of the PPS resin composition and the laser light transmitting member 1 are brought into contact with each other.
(C) Next, the laser beam 3 is irradiated while appropriately adjusting the laser beam 3 so that the laser beam 3 is transmitted through the laser beam transmitting member 1 and absorbed by the laser beam absorbing member 2. Irradiation is performed while scanning a necessary portion.
(D) The irradiated laser beam 3 passes through the laser beam transmitting member 1 and reaches the laser beam absorbing member 2, and is absorbed by the laser beam absorbing member 2 by the action of a laser beam absorbent or the like to generate heat. Raise and fuse both members 1 and 2 by heat melting.
(E) The fusion site of both members 1 and 2 is cooled and solidified, so that the welding target portions of the laser light transmitting member 1 and the laser light absorbing member 2 are joined to each other.

Laser welded body manufacturing process example 2 (FIGS. 2 and 3)
(F) A plurality of laser light transmitting members 1 using the laser light transmitting colored resin composition of the present invention are molded.
(G) A laser light-absorbing thin layer 4 (for example, a laser light-absorbing film made of a PPS resin composition) is interposed between welding target portions of the plurality of laser light-transmissive members 1.
Alternatively, the laser light absorbing thin layer 5 is formed on one (or both) of both surfaces of the plurality of laser light transmitting members 1 to be welded to each other. The laser light absorbing thin layer 5 can be formed, for example, by applying (or printing or the like) a resin ink having a laser light absorbing property on the target surface and solidifying it.
(H) Next, the laser light 3 passes through the laser light transmissive member 1 from a plurality of directions (one laser light transmissive member 1 side and the other laser light transmissive member 1 side), and the laser Irradiation is performed while appropriately adjusting each laser beam 3 so as to be absorbed by the light-absorbing thin layer 4 (5). Irradiation is performed while scanning a necessary portion.
(I) Each laser beam 3 irradiated from a plurality of directions passes through the laser beam transmitting member 1 and reaches the laser beam absorbing thin layer 4 (or 5), and the laser beam is obtained by the action of a laser beam absorber or the like. Absorbed by the absorbent thin layer 4 (or 5) to generate heat, both the laser light transmissive member 1 and the laser light absorbent thin layer 4 (or 5) constituting the laser light absorbent-containing layer are thermally melted. To fuse. The laser light absorbing thin layer 4 (or 5) is heated by irradiating the laser light 3 from the side of the one laser light transmitting member 1 to contain both the laser light transmitting member 1 and the laser light absorber. It is also possible to melt the laser light-absorbing thin layers 4 (or 5) constituting the layers, respectively, and fuse them.
(J) When the fusion site of both laser light transmitting members 1 and laser light absorbing member 4 (or 5) is cooled and solidified, the welding target portions of both laser light transmitting members 1 become laser light absorbing members. Join through 4 (or 5).
In the method for producing a laser welded body according to the present invention, since the molding accuracy of the laser light transmitting member is high, it is possible to prevent the gap between the two members at the contact portion of the laser light absorbing member from becoming large. Laser welding can be performed with a simple apparatus. In the method for producing a laser welded body of the present invention, the gap between the two members is preferably 0 to 0.05 mm.

  The laser welded body obtained by the production method of the present invention has high fastness such as heat resistance and light resistance, good migration resistance, chemical resistance, etc., and exhibits a vivid hue.

  Examples of main applications of the laser light-transmitting colored resin composition, the laser light-transmitting member, and the laser welded body obtained by the manufacturing method of the present invention include OA equipment, printed circuit boards, and automobile parts. it can. More specifically, for example, an instrument panel in the interior and a resonator (silencer) in the engine room can be mentioned. When joining parts made of thermoplastic resin, conventionally, since it is difficult to use an adhesive if the surface is untreated, it has been necessary to devise methods such as pretreatment of the surface. On the other hand, laser welding does not require a troublesome process such as pretreatment or alloying of the resin, and is superior in strength and recycling compared to the case where an adhesive is used.

EXAMPLES Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.
(Example 1)

eBIND LTW-8400C (Laser light transmissive colorant for PPS resin manufactured by Orient Chemical Industry Co., Ltd. ["eBIND" and "LTW" are both registered trademarks]) fortron 1130A6 (polyplastics glass fiber 30 weight) % Containing PPS resin [trade name]) and weighed and mixed them so that they were diluted 25 times, and the resulting mixture was used with an injection molding machine (trade name: Si-50, manufactured by Toyo Machine Metal Co., Ltd.). When injection molding is performed by a normal method at a cylinder temperature of 320 ° C. and a mold temperature of 130 ° C. using a mold having a rectangular parallelepiped shape of 80 mm in length, 50 mm in width, and 1 mm in thickness, the appearance and surface gloss are good and color A uniform black laser light-transmitting test piece (FIG. 4) with no unevenness was obtained.
(Example 2)

Both of eBIND LTW-8400C were weighed and mixed so as to be diluted 25-fold with Fortron 1130A6, and the resulting mixture was used with an injection molding machine (trade name: Si-50, manufactured by Toyo Kikai Co., Ltd.) When a mold having a rectangular parallelepiped cavity with a length of 80 mm x width 50 mm x thickness 1 mm is injection-molded by a normal method at a cylinder temperature of 320 ° C and a mold temperature of 140 ° C, the appearance and surface gloss are good and the color unevenness A uniform black laser light-transmitting test piece (FIG. 4) was obtained.
(Example 3)

Both of eBIND LTW-8400C were weighed and mixed so as to be diluted 25-fold with Fortron 1130A6, and the resulting mixture was used with an injection molding machine (trade name: Si-50, manufactured by Toyo Machine Metal Co., Ltd.) When injection molding is performed by a normal method at a cylinder temperature of 320 ° C. and a mold temperature of 150 ° C., using a mold having a rectangular parallelepiped shape of 80 mm long × 50 mm wide × 1 mm thick, the appearance and surface gloss are good and the color unevenness A uniform black laser light-transmitting test piece (FIG. 4) was obtained.
Example 4

eBIND LTW-8400C was weighed and mixed so as to be diluted 10-fold with Fortron 1140A6 (PPS resin containing 40% by weight of glass fiber manufactured by Polyplastics Co., Ltd. [trade name]), and the resulting mixture was Using an injection molding machine (trade name: Si-50, manufactured by Toyo Kikai Metals Co., Ltd.), a cylinder having a rectangular parallelepiped shape of 80 mm in length, 50 mm in width, and 1 mm in thickness is used. When injection molding was carried out at ordinary temperature at 0 ° C., a uniform black laser light-transmitting test piece (FIG. 4) having good appearance and surface gloss and no color unevenness was obtained.
(Example 5)

Both of eBIND LTW-8400C were weighed and mixed so as to be diluted 25-fold with Fortron 1140A6, and the resulting mixture was used with an injection molding machine (trade name: Si-50, manufactured by Toyo Kikai Co., Ltd.) When injection molding is performed by a normal method at a cylinder temperature of 320 ° C. and a mold temperature of 150 ° C., using a mold having a rectangular parallelepiped shape of 80 mm long × 50 mm wide × 1 mm thick, the appearance and surface gloss are good and the color unevenness A uniform black laser light-transmitting test piece (FIG. 4) was obtained.
(Example 6)

Both of eBIND LTW-8400C were weighed and mixed so as to be diluted 50 times with Fortron 1140A6, and the resulting mixture was used with an injection molding machine (trade name: Si-50, manufactured by Toyo Kikai Co., Ltd.) When injection molding is performed by a normal method at a cylinder temperature of 320 ° C. and a mold temperature of 150 ° C., using a mold having a rectangular parallelepiped shape of 80 mm long × 50 mm wide × 1 mm thick, the appearance and surface gloss are good and the color unevenness A uniform black laser light-transmitting test piece (FIG. 4) was obtained.
(Example 7)

Both of eBIND LTW-8400C were weighed and mixed so as to be diluted 25 times with TORELINA A604 (PPS resin [trade name] containing 40% by weight of glass fiber manufactured by Toray Industries, Inc.), and the resulting mixture was injected into an injection molding machine. (Product name: Si-50, manufactured by Toyo Machine Metal Co., Ltd.), with a mold having a rectangular parallelepiped shape of 80 mm long x 50 mm wide x 1 mm thick, usually at a cylinder temperature of 320 ° C and a mold temperature of 150 ° C As a result of injection molding, a uniform black laser light-transmitting test piece (FIG. 4) having good appearance and surface gloss and no color unevenness was obtained.
(Comparative Example 1)

C. I. Solvent Violet 13 purple dye and C.I. I. A mixed colorant blended with a yellow dye of Solvent Yellow 114 (blending weight ratio 5: 1) was weighed and mixed so that 0.2 wt% was added to Fortron 1130A6, and the resulting mixture was mixed. Using an injection molding machine (trade name: Si-50, manufactured by Toyo Machine Metal Co., Ltd.), a cylinder temperature of 320 ° C. and a mold temperature of a mold having a rectangular parallelepiped cavity of 80 mm long × 50 mm wide × 1 mm thick When injection molding was carried out at 120 ° C. by a usual method, a black laser light transmission test piece (FIG. 4) having a dull appearance and surface gloss was obtained.
(Comparative Example 2)

C. I. Solvent Violet 13 purple dye and C.I. I. A mixed colorant blended with a yellow dye of Solvent Yellow 114 (blending weight ratio 5: 1) was weighed and mixed so that 0.2 wt% was added to Fortron 1140A6, and the resulting mixture was mixed. Using an injection molding machine (trade name: Si-50, manufactured by Toyo Machine Metal Co., Ltd.), a cylinder temperature of 320 ° C. and a mold temperature of 90 ° C. are provided by a mold having a rectangular parallelepiped shape of 80 mm long × 50 mm wide × 1 mm thick. When injection molding was carried out at ordinary temperature at 0 ° C., a black laser light-transmitting test piece (FIG. 4) having a dull appearance and surface gloss was obtained.
(Comparative Example 3)

C. I. Pigment Violet 37 purple pigment was weighed and mixed so that 0.2 wt% was added to Fortron 1140A6, and the resulting mixture was injected into an injection molding machine (trade name: Si-50, manufactured by Toyo Machine Metal Co., Ltd.). ), And injection molding by a normal method at a cylinder temperature of 320 ° C. and a mold temperature of 150 ° C. using a die having a rectangular parallelepiped shape of 80 mm long × 50 mm wide × 1 mm thick. A dull purple laser light transmission test piece (FIG. 4) was obtained.
(Comparative Example 4)

  Fortron 1130A6 was molded using a mold having a rectangular parallelepiped shape of 80 mm long, 50 mm wide and 1 mm thick using an injection molding machine (trade name: Si-50, manufactured by Toyo Kikai Co., Ltd.), and the cylinder temperature was 320 ° C. Then, when injection molding was performed at a mold temperature of 150 ° C. by a normal method, a yellowish white laser light transmission test piece (FIG. 4) was obtained.

  (Evaluation of the physical properties)

The physical properties of the laser light transmitting colored resin compositions and laser light transmitting test pieces in Examples 1 to 7 and Comparative Examples 1 to 4 were evaluated as follows. The results are shown in Tables 1 and 2.
(1) DSC measurement

The portion A of the laser light transmitting test piece 10 (near the diagonal with respect to the gate position G as shown in FIG. 4) is cut out with a nipper to make a small piece, which is a DSC measuring instrument (manufactured by Seiko Instruments Inc., product number: SII). Using EXSTAR 6000), the temperature is increased from 30 ° C. to 330 ° C. at a rate of 10 ° C./min, and then the temperature is decreased from 330 ° C. to 30 ° C. at a rate of 10 ° C./min. The turning point was confirmed.
The DSC curves for Example 3, Example 4, Example 5, Example 6, and Comparative Example 2 are shown in FIGS. 7, 8, 9, 10, and 11, respectively.
(2) TG / DTA measurement

Using the TG / DTA measuring device (trade name: SII EXSTAR6000, manufactured by Seiko Instruments Inc.) for each colorant powder sample of each example and comparative example, from 30 ° C. to 550 ° C. in an air (air) atmosphere of 200 ml / min. The temperature was raised at a rate of 10 ° C./min, and measurement was performed, and it was confirmed whether an endothermic peak was included between 200 ° C. and 300 ° C.
The TG / DTA curve for eBIND LTW-8400C is shown in FIG.
(3) Glossiness measurement

Using a gloss meter (trade name: HG-268, manufactured by Suga Test Instruments Co., Ltd.), the glossiness of each laser light transmissive test piece in a light beam with an angle of 60 degrees was measured.
The higher the measurement value, the higher the glossiness.
(4) Sled amount

When each laser light transmissive test piece 10 is placed on a horizontal surface 12 as shown in FIG. 5 and the corner near the gate position G of each laser light transmissive test piece 10 is pushed by a weight W of 100 g, the diagonal is The height h floating with respect to the horizontal plane 12 was measured with a caliper to determine the amount of warpage.
(5) Laser welding test

  0.5 parts of carbon black was added to the glass fiber-containing resin used in each Example and Comparative Example, and a laser light absorbing test piece 14 was produced in the same manner as in each Example and Comparative Example.

Next, as shown in FIG. 6, the laser light transmitting test piece 10 and the laser light absorbing test piece 14 are overlapped using a jig J, and a glass plate P is placed thereon, and then an air clamp. C was set by applying pressure (0, 0.2 MPa, 0.4 MPa). A laser diode R (wavelength: 940 nm continuous) (manufactured by Fine Device) from above the glass plate is used to apply laser light R (output 25 W, scanning speed 5 mm / sec, spot diameter 0.6 mm) to the depth in FIG. Irradiation was performed while scanning in the direction over 30 mm.
(6) Tensile strength test

  For the welded body obtained in (5), according to JISK7113-1995, the tensile tester (trade name: AG-50kNE, manufactured by Shimadzu Corporation) is used in the longitudinal direction of the welded body (direction in which the welded part is pulled away). A tensile test was conducted at a test speed of 10 mm / min to measure the tensile weld strength.

  In Table 1, * 1 indicates C.I. I. Solvent Violet 13 and C.I. I. The mixed colorant of Solvent Yellow 114 (blending weight ratio 5: 1) is shown.

  As shown in Table 2, when the amount of warpage of the laser light transmitting test piece is 0.5 mm or less, the laser light absorbency can be obtained even when the clamping pressure is 0 and the loading pressure is only due to the weight of the glass plate P. Practically sufficient welding strength could be secured with the test piece. On the other hand, when the amount of warpage of the laser light transmitting test piece exceeds 0.5 mm, sufficient welding strength can be obtained by the gap between the laser light absorbing test piece even if the clamp pressure is adjusted. There wasn't.

It is a perspective view which shows the laser welding body manufacturing process example 1. FIG. It is a perspective view which shows the laser welding body manufacturing process example 2. FIG. It is a perspective view which shows the laser welding body manufacturing process example 2. FIG. It is a perspective view of a laser beam permeability test piece. It is a perspective view which shows curvature amount measurement. It is a schematic cross section which shows a laser welding test. 6 is a DSC curve for Example 3. 6 is a DSC curve for Example 4. 6 is a DSC curve for Example 5. 7 is a DSC curve for Example 6. 6 is a DSC curve for Comparative Example 2. FIG. 4 is a TG / DTA curve for eBIND LTW-8400C.

Explanation of symbols

10 Laser light transmission test piece 12 Horizontal surface 14 Laser light absorption test piece C Air clamp G Gate position J Jig L Diode laser welding machine P Glass plate R Laser light W Weight h Height

Claims (11)

A laser light transmitting colored resin composition containing at least a polyphenylene sulfide resin and a colorant, wherein the colorant has an endothermic peak between 200 ° C. and 300 ° C. in a TG / DTA thermal analysis. In the DSC thermal analysis, the crystallization point T _C of the laser light transmitting colored resin composition is the same as the laser light transmitting colored resin composition except that it does not contain the colorant. is the difference between the _N T _C -T _N are laser ray transmitting colored resin composition, characterized in that at 0 ℃ or higher. The T _C -T _N is, 5 ° C. or more and 30 ° C. less claim 1 laser ray transmitting colored resin composition.   A laser light transmitting member comprising the laser light transmitting colored resin composition according to claim 1 and having one each of an exothermic energy peak and an endothermic energy peak in DSC thermal analysis.   4. The laser beam transmitting member according to claim 3, wherein the glossiness is 100 or more under the measurement condition of a luminous flux of 60 degrees.   The laser beam transmitting member according to claim 3 or 4, wherein a warp amount is 0.5 mm or less.   A laser light transmitting colored resin composition for forming a laser light transmitting member, comprising the laser light transmitting colored resin composition according to claim 1.   3. A method for producing a laser light transmissive member comprising molding the laser light transmissive colored resin composition according to claim 1 or 2 so as to have one each of an exothermic energy peak and an endothermic energy peak in DSC thermal analysis. .   A laser-welding member for laser welding comprising the laser-light-transmitting colored resin composition according to claim 1 and having one each of an exothermic energy peak and an endothermic energy peak in DSC thermal analysis.   6. The laser light absorbing member transmits laser light for laser welding through the laser light transmissive member in a state where the laser light transmissive member and the laser light absorptive member substantially contact each other. A method for manufacturing a laser welded body in which a contact portion between the two members is welded by irradiating so as to be absorbed by the adhesive member.   10. The method for producing a laser welded body according to claim 9, wherein a gap between the members at the contact portion between the laser light transmitting member and the laser light absorbing member is 0 to 0.05 mm. A method of manufacturing a welded body by welding one member and the other member,
The one member is a laser light transmitting member according to claim 3, 4 or 5,
In a state where the one member and the other member are substantially brought into contact with each other via a laser light absorbing thin layer, the laser light absorbing laser beam is transmitted through the laser light transmitting member. A method for producing a laser welded body in which the two members are welded via a laser light absorbing thin layer by irradiating the thin layer so as to absorb.

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