JP5475412B2 - Thermoplastic resin composition - Google Patents

Description

  The present invention relates to a thermoplastic resin composition characterized by forming a molded body used for joining selected from vibration welding, hot plate welding, and laser welding. Specifically, in welding of the thermoplastic resin composition and other members, when not only the suppression of burr generation during vibration welding, stringing property during hot plate welding, and laser welding properties are excellent, but also a molded body. The present invention relates to a thermoplastic resin composition having an excellent surface appearance.

Conventionally, vibration welding, hot plate welding, and laser welding are known as methods for joining thermoplastic resins.
Among them, in the vibration welding method, a so-called burr that the molten resin protrudes from the welded portion is generated, and the appearance is impaired due to the adhesion to the surface of the molded product.
Further, in the hot plate welding method, after the resin is melted by the hot plate at the time of joining, the resin is stretched into a thread shape when it is separated from the hot plate (hereinafter referred to as stringing property), and the appearance is similarly impaired. Cause a bug.
Further, in the laser welding method, problems such as melting and smoke generation of the resin occur on the laser beam incident surface.

Japanese Patent Application Laid-Open No. 2004-182835 (Patent Document 1) describes that the defects during welding are improved by setting the gel content of the thermoplastic resin to 70% or more, and Japanese Patent Application Laid-Open No. 2005-112991 (Patent Document 2). Describes that the use of a thermoplastic resin composition containing a crosslinked acrylic rubber suppresses the generation of burrs during vibration welding. Japanese Patent Application Laid-Open No. 2007-8974 (Patent Document 3) describes that laser weldability can be improved by using a thermoplastic resin having an alkali metal content of a certain value or less. No. 2007-91969 (Patent Document 4) describes that a thermoplastic resin containing a polyorganosiloxane and having a specific reduced viscosity has a good appearance of a molded product and does not generate burrs during vibration welding.
However, there is still no thermoplastic resin excellent not only in the weldability (welded appearance) of each method but also in the surface appearance when formed into a molded body, and a thermoplastic resin that satisfies all of the above-described problems is demanded.

JP 2004-182835 A

JP 2005-112991 A

JP 2007-8974 A

JP 2007-91969 A

  The object of the present invention is to improve the burr at the time of vibration welding, the improvement of the stringiness at the time of hot plate welding, the improvement of the laser welding property, and the molded body in the welding of the thermoplastic resin composition and other members. An object of the present invention is to provide a thermoplastic resin composition having an excellent surface appearance.

  As a means for solving such problems, the present inventors have used a graft copolymer and / or copolymer in which a polyfunctional monomer is copolymerized to obtain a surface appearance when formed into a molded body. The present inventors have found that a thermoplastic resin composition that does not cause the above-described problems can be obtained during bonding selected from vibration welding, hot plate welding, and laser welding.

That is, the thermoplastic resin composition of the present invention can be copolymerized with a styrenic monomer and the monomer in the presence of a rubber-like polymer (however, a polyfunctional monomer is not copolymerized). Copolymer obtained by copolymerizing graft copolymer (A) obtained by graft polymerization of other monomers, styrene monomer, and other monomers copolymerizable with the monomer A thermoplastic resin composition comprising the blend (B), wherein one or both of the graft copolymer (A) and the copolymer (B) is copolymerized with a polyfunctional monomer, and the thermoplastic resin composition A polyfunctional monomer is copolymerized in an amount of 0.21 to 5 parts by weight in 100 parts by weight of the product.

  According to the present invention, in welding a thermoplastic resin composition to another member, improvement of burr at vibration welding, improvement of stringing property at hot plate welding, improvement of laser welding property, further molding It is possible to provide a thermoplastic resin composition having an excellent surface appearance at the time.

The present invention will be described in detail below.
The thermoplastic resin composition used in the present invention is obtained by graft polymerization of a styrene monomer and another monomer copolymerizable with the monomer in the presence of a rubbery polymer. Thermoplastic resin composition comprising copolymer (B) obtained by copolymerizing copolymer (A) and / or styrene monomer and other monomer copolymerizable with the monomer In the above, a polyfunctional monomer is copolymerized in one or both of the graft copolymer (A) and the copolymer (B), and a polyfunctional monomer in 100 parts by weight of the thermoplastic resin composition. It is a thermoplastic resin composition in which the body is 0.1 to 5 parts by weight copolymerized.

  As a polymerization method of the graft copolymer (A) and the copolymer (B) used in the present invention, a known method such as an emulsion polymerization method, a solution polymerization method, a suspension polymerization method, a bulk polymerization method, or the like may be employed. Can do.

  The rubbery polymer used in the graft copolymer (A) used in the present invention is not particularly limited, but polybutadiene rubber, styrene-butadiene rubber (SBR), styrene-butadiene-styrene (SBS) block copolymer. Styrene- (ethylene-butadiene) -styrene (SEBS) block copolymer, acrylonitrile-butadiene rubber (NBR), diene rubber such as butyl acrylate-butadiene, butyl acrylate rubber, butadiene-butyl acrylate rubber, 2-ethylhexyl acrylate- Acrylic rubbers such as butyl acrylate rubber, 2-ethylhexyl methacrylate-butyl acrylate rubber, stearyl acrylate-butyl acrylate rubber, polyorganosiloxane-butyl acrylate composite rubber, ethylene-propyl Ngomu, ethylene - propylene - polyolefin rubber polymer such as diene rubber, silicone rubber polymers such as polyorganosiloxane rubber and the like, which may be used alone or in combination. In particular, polybutadiene rubber, styrene-butadiene rubber, butyl acrylate rubber, and ethylene-propylene-diene rubber are preferable. It is possible to use the polyfunctional monomer specified in the present invention when producing the rubbery polymer, but the polyfunctional monomer copolymerized with the rubbery polymer is It is not included in the polyfunctional monomer that is required to be contained in 0.1 to 5 parts by weight in 100 parts by weight of the thermoplastic resin composition defined in the invention.

  The weight average particle diameter of the rubber-like polymer used for the graft copolymer (A) is preferably in the range of 0.05 to 1.0 μm from the viewpoint of the surface appearance when formed into a molded body, 0.5 is more preferable.

  Examples of the styrenic monomer used in the graft copolymer (A) and the copolymer (B) include styrene, α-methylstyrene, paramethylstyrene, bromostyrene, and the like, and one or more are used. be able to. In particular, styrene and α-methylstyrene are preferable.

  Examples of other monomers copolymerizable with the styrene monomer used in the graft copolymer (A) and the copolymer (B) include vinyl cyanide monomers such as acrylonitrile and methacrylonitrile. , (Meth) acrylic acid ester monomers such as methyl methacrylate and methyl acrylate, maleimide monomers such as N-phenylmaleimide and N-cyclohexylmaleimide, acrylic acid, methacrylic acid, itaconic acid, fumaric acid, etc. These unsaturated carboxylic acid monomers and polyfunctional monomers can be used, and these can be used alone or in combination of two or more.

  Examples of the polyfunctional monomer used in the graft copolymer (A) and the copolymer (B) include divinylbenzene, allyl (meth) acrylate, ethylene glycol di (meth) acrylate, diallyl phthalate, and dicyclopentadiene. Di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, triallylcia Examples thereof include nurate and triallyl isocyanurate, and one or more can be used.

  The usage-amount of a polyfunctional monomer is 0.1-5 weight part with respect to 100 weight part of thermoplastic resin compositions. If the polyfunctional monomer is less than 0.1 parts by weight, in welding with other members, improvement of stringing property during hot plate welding, improvement of burrs during vibration welding, and improvement of laser welding property In addition, when the amount is more than 5 parts by weight, the surface appearance when formed into a molded product is not preferable.

  The thermoplastic resin composition in the present invention may contain various additives as necessary, for example, known antioxidants, light stabilizers, lubricants, plasticizers, antistatic agents, colorants, flame retardants, matting agents and fillers. Etc. can be suitably added.

  Although the thermoplastic resin composition in the present invention can be used alone, it can also be used by mixing with other thermoplastic resins as necessary. Examples of such other thermoplastic resins include polycarbonate resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polyamide resin, polymethyl methacrylate resin, polylactic acid resin, rubber-reinforced polystyrene resin (HIPS resin), acrylonitrile-ethylene / propylene. Examples include styrene resin (AES resin) and methyl methacrylate-butadiene-styrene resin (MBS resin).

  The thermoplastic resin composition in the present invention can be obtained by mixing the above-described components. In order to mix, well-known kneading apparatuses, such as an extruder, a roll, a Banbury mixer, and a kneader, can be used, for example.

  Furthermore, the thermoplastic resin composition in the present invention can be molded by a known molding method such as extrusion molding, injection molding, blow molding, press molding and the like, and various molded products can be produced.

  When the molded product produced from the thermoplastic resin composition in the present invention is welded to other members such as a resin produced using a thermoplastic resin such as polycarbonate resin, ABS resin or polymethyl methacrylate resin, A plate welding method, a vibration welding method or a laser welding method can be preferably used.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In addition, the part and% which are shown in an Example are based on a weight.

Production of graft copolymer (A-1) 50 parts by weight of butadiene-based rubber polymer latex, 100 parts by weight of deionized water, 0.2 parts by weight of lactose in terms of solid content in a nitrogen-replaced glass reactor After adding an aqueous solution in which 0.1 part by weight of anhydrous sodium pyrophosphate and 0.005 part by weight of ferrous sulfate were dissolved, the temperature was raised to 70 ° C. Thereafter, 1.0 part by weight of potassium oleate is added to 15 parts by weight of acrylonitrile, 35 parts by weight of styrene, 0.05 part by weight of tertiary decyl mercaptan, 0.3 part by weight of cumene hydroperoxide and 20 parts by weight of deionized water. The dissolved emulsifier aqueous solution was continuously added over 4 hours. Thereafter, the polymerization was continued for 3 hours to complete the polymerization. Thereafter, salting out, dehydration and drying were performed to obtain a graft polymer (A-1).

  The used butadiene rubber polymer latex was freeze-dried with a cryotrans folder of an electron microscope JEM-1400 manufactured by JEOL, and photographed with an electron microscope JEM-1400. Each particle area is measured using an image analysis process (apparatus name: IP-1000PC manufactured by Asahi Kasei Co., Ltd.), the equivalent circle diameter (radius) is obtained, and the weight average particle diameter of the butadiene rubber polymer latex is calculated. As a result, the weight average particle diameter was 0.12 μm.

Production of graft copolymer (A-2) Same as graft copolymer (A-1) except that 35 parts by weight of styrene was changed to 31 parts by weight of styrene and 4.0 parts by weight of allyl methacrylate. To obtain a graft polymer (A-2).

A continuous bulk polymerization apparatus was used in which two complete mixing tanks of 10 liters were connected in series to a plug flow column type reaction tank having a production volume of the graft copolymer (A-3) of 15 liters. The plug flow tower type reaction vessel constitutes the particle formation step, the first complete mixing vessel as the second reactor constitutes the particle size adjustment step, and the third reactor constitutes the post-polymerization step. In a plug flow column reactor, 37 parts by weight of ethylbenzene, 79 parts by weight of styrene, 26 parts by weight of acrylonitrile, 3 parts by weight of allyl methacrylate, 10 parts by weight of Nipol NS320S manufactured by Nippon Zeon Co., Ltd., t-dodecyl A raw material consisting of 0.3 part by weight of mercaptan, 0.08 part by weight of 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane was prepared, and this raw material was added to a three-stage stirred polymerization tank row The monomer was polymerized by continuously feeding the reactor at 10 kg / hr. The polymerization solution was led from the third-stage tank to a separation and recovery step comprising a preheater and a decompression chamber.

  The resin from the recovery step was subjected to an extrusion step to obtain a graft copolymer (A-3) as granular pellets. The composition of the pellet was analyzed by pyrolysis chromatography. As a result, the diene rubber component was 16% by weight, the styrene monomer component was 62% by weight, the acrylonitrile monomer component was 20% by weight, and the allyl methacrylate monomer component was 2% by weight. Met.

Production of copolymer (B-1) A nitrogen-replaced glass reactor was charged with 150 parts by weight of deionized water, 10% of a mixed monomer of 70 parts by weight of styrene and 30 parts by weight of acrylonitrile, sodium dodecylbenzenesulfonate, 0. 5 parts (in terms of solid content) and 0.3 part by weight of potassium persulfate were charged and polymerized at 65 ° C. for 1 hour. Thereafter, 30 parts by weight of an emulsifier aqueous solution containing the remaining mixed monomer solution and 2.5 parts by weight of sodium dodecylbenzenesulfonate (in terms of solid content) was continuously added over 3 hours, and then polymerization was continued for 2 hours. Ended. Thereafter, salting out, dehydration and drying were performed to obtain a copolymer (B-1).

Production of copolymer (B-2) Similar to copolymer (B-1), except that 70 parts by weight of styrene was changed to 69.7 parts by weight of styrene and 0.3 parts by weight of allyl methacrylate. Manufactured to obtain a copolymer (B-2).

Production of copolymer (B-3) Similar to copolymer (B-1), except that 70 parts by weight of styrene was changed to 67.0 parts by weight of styrene and 3.0 parts by weight of allyl methacrylate. Manufactured to obtain a copolymer (B-3).

Production of copolymer (B-4) A copolymer (B-1) was produced in the same manner as copolymer (B-1) except that 70 parts by weight of styrene was changed to 64 parts by weight of styrene and 6 parts by weight of allyl methacrylate. A polymer (B-4) was obtained.

Production of copolymer (B-5) A copolymer (B-1) was produced in the same manner as copolymer (B-1) except that 70 parts by weight of styrene was changed to 60 parts by weight of styrene and 10 parts by weight of allyl methacrylate. A polymer (B-5) was obtained.

Production of copolymer (B-6) Similar to copolymer (B-1), except that 70 parts by weight of styrene was changed to 68.5 parts by weight of styrene and 1.5 parts by weight of divinylbenzene. Manufactured to obtain a copolymer (B-6).

Production of copolymer (B-7) A formalin condensate of 160 parts pure water, 2.5 parts potassium rosinate, 0.5 parts potassium oleate and sodium naphthalenesulfonate in a nitrogen-replaced glass reactor. 0.7 parts, 0.08 parts of sodium hydroxide, 68.5 parts of α-methylstyrene, 1.5 parts by weight of allyl methacrylate, 30 parts of acrylonitrile, 0.15 parts of t-dodecyl mercaptan and added with sufficient stirring to 70 parts After raising the temperature to 0 ° C., 0.7 part of potassium persulfate was charged and polymerization was started at 70 ° C. When the polymerization conversion rate exceeded 68%, the reaction temperature was raised to 76 ° C. and the reaction was continued. After confirming that the polymerization conversion rate exceeded 96%, the polymerization was terminated. Thereafter, salting out, dehydration and drying were performed to obtain a copolymer (B-7).

  After mixing the components shown in Table 1 and Table 2 in the proportions shown in Table 1 and Table 2, 1.0 part by weight of carbon # 45B (Mitsubishi Chemical Corporation) was mixed, and 240 parts using a 40 mm twin screw extruder. The mixture was melt kneaded at 0 ° C. to obtain colored pellets (1).

Evaluation of surface appearance The above-mentioned colored pellets (1) of Examples 1 to 9 and Comparative Examples 1 to 4 were injection-molded using an injection molding machine under the conditions of a cylinder temperature of 240 ° C and a mold temperature of 50 ° C. (150 mm × 120 mm × 3 mm) was created. The surface appearance of the molded product was evaluated by measuring the surface gloss according to ASTM D-523.
A: 90% or more, B: 75% or more and less than 90%, X: Less than 75%

Evaluation of hot plate weldability The above-obtained colored pellets (1) of Examples 1 to 9 and Comparative Examples 1 to 4 were injection molded using an injection molding machine under conditions of a cylinder temperature of 240 ° C and a mold temperature of 50 ° C. Thus, ASTM No. 1 dumbbell for hot plate weldability evaluation was prepared. After pressing the ASTM No. 1 dumbbell obtained by injection molding at a pressure of 10 kgf / cm ² for 30 seconds on an aluminum flat plate heated to 280 ° C., the dumbbell was lifted at a speed of 500 mm / min. It was determined whether stringing occurred.
◎: No stringing, ○: Slight stringing, ×: Stringing

Evaluation of vibration weldability The above-mentioned colored pellets (1) of Examples 1 to 9 and Comparative Examples 1 to 4 were injection molded using an injection molding machine under conditions of a cylinder temperature of 240 ° C. and a mold temperature of 50 ° C. A molded article having a welding evaluation property (width 150 mm × length 90 mm × thickness 3 mm) was prepared. In addition, as an evaluation material, polymethylmethacrylate resin (“Sumipex MHF” (trade name) manufactured by Sumitomo Chemical Co., Ltd.) is used for injection molding under the conditions of a cylinder temperature of 240 ° C. and a mold temperature of 50 ° C. A box-shaped (width 120 mm × length 180 mm × height 20 mm × thickness 3 mm) molded product was obtained. A molded product obtained from this evaluation material and the molded product for vibration welding evaluation are produced by BRANSON manufactured by Nippon Emerson.
VIBRATION WELDER type 2406) was used for vibration welding under vibration welding conditions of amplitude: 0.5 mm, pressure: 0.24 MPa, and sinking amount: 1.0 mm.
In addition, the appearance evaluation result of the welded portion is shown in three stages of ○, Δ, and × in ascending order of the spread of the thermoplastic resin in the burrs of the welded portion.

Evaluation of laser weldability In order to perform laser welding, a laser transmitting material and a laser absorbing material are required. As a laser transmission side material, polymethylmethacrylate resin (“SUMIPEX MHF” (trade name) manufactured by Sumitomo Chemical Co., Ltd.) is injection-molded using an injection molding machine under conditions of a cylinder temperature of 240 ° C. and a mold temperature of 50 ° C. Thus, a test piece of laser transmission side material having a thickness of 2 mm, a width of 55 mm, and a length of 90 mm was obtained.
After mixing the components shown in Table 1 and Table 2 as laser absorption side materials in the proportions shown in Table 1 and Table 2, carbon black carbon # 45B (manufactured by Mitsubishi Chemical Corporation) and titanium oxide are added to each mixture, Using a 40 mm twin screw extruder, it was melt kneaded at 240 ° C. to obtain colored pellets (2). The addition amounts of carbon black and titanium oxide were appropriately adjusted so that the colored pellets (2) of Examples 1 to 9 and Comparative Examples 1 to 4 all had the same hue. The hues of the reference plates having the same hue are L * (D65) = 41, a (D65) = 3, b (D65) = − 10 (Spectrophotometer CMS-35SP manufactured by Murakami Color Research Co., Ltd.) Measurement). The obtained colored pellet (2) was injection-molded in the same manner as the permeation side material to obtain a test piece having a thickness of 2 mm × width of 55 mm × length of 90 mm.

The laser transmission side test piece and the laser absorption side test piece obtained above are set in a jig so that the short side portions overlap each other and have a width of 25 mm × width of 55 mm so that the weld seam width becomes 1 mm. Welding was performed under the following conditions.
Laser welding was performed by irradiating from the laser transmission side test piece side with a laser beam wavelength of 808 nm, an output of 6 W, and a scanning speed of 6 mm / s.
About the obtained laser welding test piece, the tensile shear test was implemented using Shimadzu Corporation autograph: AGS-5KN. The pulling speed was 50 mm / min, and the distance between chucks was 135 mm.

The strength of the laser weld surface and the appearance of the weld appearance in the tensile shear test were determined according to the following criteria.
○: Welding (bonding) strength is good, and no welding mark (coagulation) is observed on the welding surface.
Δ: Welding (bonding) strength was good, and some welding marks (coagulation) were observed on the welding surface.
X: Welding (bonding) strength is weak, and a welding mark (cog) is seen on the welding surface, or a significant color difference is seen on the welding surface.

  The evaluation results according to the resin compositions of Examples 1 to 9 and Comparative Examples 1 to 4 are summarized in Tables 1 and 2.

  As shown in Table 1, Examples 1 to 9 are examples of the thermoplastic resin composition according to the present invention, and have good hot plate weldability, vibration weldability and laser weldability, and when formed into a molded body. Excellent surface appearance.

  As shown in Table 2, Comparative Example 1, Comparative Example 3, and Comparative Example 4 are examples in which a polyfunctional monomer is not included in the thermoplastic resin composition, and hot plate weldability, vibration weldability, laser The weldability was poor. In Comparative Example 2, since the content of the polyfunctional monomer exceeded the upper limit, the hot plate weldability, vibration weldability, and laser weldability were good, but the surface appearance was inferior.

The thermoplastic resin composition of the present invention not only has excellent hot plate weldability, vibration weldability, and laser weldability with other members, but also has excellent surface appearance of molded products. It is suitable for application to products that need to be joined and integrated.

Claims (4)

Obtained by graft polymerization of a styrenic monomer and other monomers copolymerizable with the monomer in the presence of a rubber-like polymer (but not copolymerizing a polyfunctional monomer) Thermoplastic resin composition comprising a graft copolymer (A) and / or a styrene monomer and a copolymer (B) obtained by copolymerizing another monomer copolymerizable with the monomer In the product, a polyfunctional monomer is copolymerized in one or both of the graft copolymer (A) and the copolymer (B), and the polyfunctional monomer is contained in 100 parts by weight of the thermoplastic resin composition. A thermoplastic resin composition characterized by forming a molded body used for joining selected from vibration welding, hot plate welding, and laser welding, in which a monomer is copolymerized in an amount of 0.21 to 5 parts by weight.
Graft copolymer (A) obtained by graft polymerizing a thermoplastic resin composition with a styrenic monomer and another monomer copolymerizable with the monomer in the presence of a rubber-like polymer And a styrene monomer and a copolymer (B) obtained by copolymerizing another monomer copolymerizable with the monomer, and at least the copolymer (B) has a polyfunctional monofunctional monomer. The thermoplastic resin composition according to claim 1, wherein the monomer is copolymerized. 3. The thermoplastic according to claim 1, wherein the polyfunctional monomer is one or more of divinylbenzene, triallyl isocyanurate, triallyl cyanurate, or allyl methacrylate. Resin composition. The molded article obtained by shape | molding the thermoplastic resin composition in any one of Claims 1-3.