JP2007112858A - Method for producing polybutylene terephthalate resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the impact resistance of a polybutylene terephthalate resin reinforced with a glass fiber while maintaining mechanical strength thereof, without using an elastomer or the like as an impact resistance improver. <P>SOLUTION: A method for producing a polybutylene terephthalate resin composition comprising (A) a polybutylene terephthalate resin, (B) a glass fiber surface-treated with a novolak epoxy resin, and (C) a carbodiimide compound comprises the steps of feeding component (A) from a feed port disposed upstream in the extrusion direction of a twin screw extruder having two or more feed ports, and feeding components (B) and (C) from a downstream feed port at the same time or feeding component (B) from a downstream feed port and then component (C) from a further downstream feed port, followed by melt-kneading the resulting mixture. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a method for producing a polybutylene terephthalate resin composition having excellent impact resistance. More specifically, the present invention relates to a method for producing a polybutylene terephthalate resin composition having excellent impact resistance and mechanical properties, and a molded article using the composition obtained by the production method.

  Polybutylene terephthalate resin has excellent mechanical properties, physical and chemical properties, and good processing characteristics such as injection molding and extrusion molding. Therefore, it is used as an engineering plastic for automobile parts, electrical / electronic parts, and other precision products. It is widely used in various applications such as machinery, building materials, and miscellaneous goods. In general, glass fibers are added to the polybutylene terephthalate resin in order to develop strength. Furthermore, with the recent expansion and diversification of applications, higher performance is often required. One of such properties is improved impact resistance, and a technique for improving impact resistance while using glass fiber in combination for maintaining strength is required. Conventionally, various methods have been proposed to achieve this purpose.

  In Patent Document 1, an elastomer such as an MBS resin or an acrylate-based core-shell graft copolymer is added to a thermoplastic resin, and it is directly molded using an injection molding machine without going through an extrusion melt kneading process. Materials are described.

  In patent document 2, impact resistance is expressed by adding an epoxide compound, a catalyst, and a butadiene-based polymer.

  Patent Document 3 shows that a thermoplastic elastomer or a core-shell polymer is used as an impact resistance imparting agent, and an aromatic polyvalent carboxylic acid ester is further added.

  All of these are made to exhibit impact resistance by using an elastomer and a core-shell polymer together. The mechanical strength is lower than when no elastomer is added due to the characteristics of the elastomer and core-shell polymer, and the required strength is achieved. There was no case.

On the other hand, Patent Document 4 describes a polyalkylene terephthalate resin composition containing an epoxy resin or polycarbodiimide. Although the hot water resistance is improved by using this method, it is insufficient to improve the impact resistance and to develop a certain mechanical strength.
Japanese Unexamined Patent Publication No. 6-32912 Japanese Patent Publication No. 6-99621 JP 2000-336258 A JP-A-60-210659

  The object of the present invention is to provide a technique for improving the impact resistance while maintaining the mechanical strength of the polybutylene terephthalate resin reinforced with glass fiber without using an elastomer or a core-shell polymer as an impact resistance improver. There is to do.

  As a result of intensive studies to achieve the above object, the present inventors have found that (A) a polybutylene terephthalate resin, (B) a glass fiber surface-treated with a novolac epoxy resin, and (C) a polybutylene containing a polycarbodiimide compound. The present inventors have found that a polybutylene terephthalate resin composition having improved impact resistance can be obtained without causing a decrease in mechanical strength by melt-kneading the terephthalate resin composition by a specific method, and the present invention is completed. It came to.

  That is, the present invention is a method for producing a polybutylene terephthalate resin composition comprising (A) a polybutylene terephthalate resin, (B) a glass fiber surface-treated with a novolac epoxy resin, and (C) a carbodiimide compound. (A) component is supplied from the raw material supply port on the upstream side in the extrusion direction of the twin screw extruder having the raw material supply port, and the (B) component and the (C) component are supplied simultaneously from the downstream raw material supply port, Alternatively, the component (A) is supplied from the raw material supply port on the upstream side in the extrusion direction of the twin-screw extruder, the component (B) is supplied from the raw material supply port downstream from the raw material supply port, and further from the raw material supply port downstream thereof (C ) A method for producing a polybutylene terephthalate resin composition, wherein components are supplied and melt-kneaded.

  Since the polybutylene terephthalate resin composition produced by the production method of the present invention is excellent in impact resistance and mechanical properties, it is a molded product for electric / electronic parts used in the automotive field and OA field, particularly a connector, It is suitably used for injection molded products such as switches, various sensors, substrate storage boxes and their peripheral parts, and housings.

  The present invention will be described in detail below. The present invention provides a twin screw extruder comprising (A) a polybutylene terephthalate resin, (B) a glass fiber surface-treated with a novolac epoxy resin, and (C) a polycarbodiimide compound, and having two or more raw material supply ports. Use and melt-knead to produce the desired composition. The rotational direction of the biaxial screw may be the same or different, and these can be arbitrarily selected. However, in the present invention, since it is necessary to cause chemical reaction or chemical interaction in the extruder, time for a certain reaction or interaction is required. Therefore, the extruder used in the present invention preferably has a residence time of at least 20 seconds. In the production method of the present invention, raw material components are supplied from different raw material supply ports (openings), but the supply method is not particularly limited. Each component may be supplied quantitatively while being measured separately, or a part of the constituent components may be mixed in advance as needed and supplied quantitatively.

  In the production method of the present invention, the degassing performed as necessary may be performed by substantially discharging the gas component out of the extruder system and may be naturally diffused into the atmosphere, but preferably the pressure is reduced. It is better to go. When the pressure is reduced, unreacted volatile compound components and other volatile components are effectively discharged out of the system. Moreover, although it is preferable to install a special opening part for deaeration, it is possible to discharge | emit a gas component also from a raw material supply port (opening part).

  In the production method of the present invention, (A) after supplying the polybutylene terephthalate resin, (C) the carbodiimide compound is the same as or later than the glass fiber surface-treated with the (B) novolac epoxy resin. As long as it is supplied at the timing, the composition is prepared by commonly used equipment and methods. That is, the component (A) is supplied from the raw material supply port on the upstream side in the extrusion direction of the twin-screw extruder having two or more raw material supply ports, and the component (B) and the component (C) are further supplied from the downstream material supply port. (A) component is supplied from the raw material supply port on the upstream side in the extrusion direction of the twin-screw extruder, and the (B) component is supplied from the downstream material supply port, and further downstream. It is essential to supply the component (C) from the supply port and melt knead. Of these, the former method requires at least two raw material supply ports, and the latter method requires at least three raw material supply ports.

  The present invention is characterized in that the component (C) is added and supplied simultaneously with the component (B) or after the component (B). (A) The carboxyl end of the polybutylene terephthalate resin is very reactive with the (C) carbodiimide compound, so (B) the (C) carbodiimide compound contacts the (A) polybutylene terephthalate resin before the glass fiber. When heated and melted, the adhesion between (A) polybutylene terephthalate resin and (B) glass fiber becomes insufficient, and the intended strength may not be obtained.

  Specifically, for example, (A) polybutylene terephthalate resin is charged and melted from the upstream raw material supply port of the twin-screw extruder, and (B) novolac epoxy resin is fed from the downstream supply port with a side feeder or the like. (A) Polybutylene terephthalate resin from a raw material supply port on the upstream side of a twin-screw extruder, or a method of forming pellets by extruding by simultaneously adding glass fiber surface-treated by (C) and a carbodiimide compound The glass fiber surface-treated with (B) novolac epoxy resin is introduced from the downstream supply port, and (C) the carbodiimide compound is further introduced into the pellet from the downstream supply port. A molding method is preferred.

  The (A) polybutylene terephthalate resin used in the present invention is a condensation polymer obtained by using terephthalic acid or dimethyl terephthalate as a dicarboxylic acid and 1,4-butanediol as a dihydroxy compound as main components.

  In addition to the main components, as dicarboxylic acids, known dicarboxylic acids such as isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenylether dicarboxylic acid, diphenylethanedicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid, sebacic acid and their alkyl, alkoxy or It may contain a halogen substituent. Dihydroxy compounds include ethylene glycol, propylene glycol, neopentyl glycol, hydroquinone, resorcin, dihydroxyphenyl, naphthalenediol, dihydroxydiphenyl ether, cyclohexanediol, 2,2-bis (4-hydroxyphenyl) propane, and diethoxylated bisphenol A. Or a polyoxyalkylene glycol and an alkyl, alkoxy, or halogen-substituted product thereof may be used, and one or a combination of two or more may be used.

  In addition, oxycarboxylic acids such as oxybenzoic acid, oxynaphthoic acid, and diphenyleneoxycarboxylic acid and derivatives capable of forming esters thereof can also be used. Further, in addition to these, a polyester having a branched or crosslinked structure in which a trifunctional monomer, that is, trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol, trimethylolpropane, or the like is used in a small amount may be used. Halogenated aromatic nuclei such as dibromoterephthalic acid, tetrabromoterephthalic acid, tetrachloroterephthalic acid, 1,4-dimethyloltetrabromobenzene, tetrabromobisphenol A, tetrabromobisphenol A ethylene or propylene oxide adducts A polyester copolymer having a halogen using a compound having a compound as a substituent and having an ester-forming group is also included. Furthermore, a polyester elastomer constituting a block copolymer of a high melting point hard segment and a low melting point hard segment can also be used. The polybutylene terephthalate resin used in the present invention preferably has an intrinsic viscosity of 0.55 dl / g or more measured at 30 ° C. using o-chlorophenol as a solvent, more preferably 0.55 to 1.2 dl / g, particularly 0.55 to 1.0. Those with dl / g are preferred.

  As the (B) glass fiber of the present invention, chopped strands are used. The glass fiber of component (B) must be surface-treated with a polyfunctional novolac epoxy resin in order to maintain adhesion with the polybutylene terephthalate resin matrix. Furthermore, a silane coupling agent can be contained as a sizing agent, for example, γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-amino) Ethyl) -N ′-(β-aminoethyl) -γ-aminopropyltrimethoxysilane, aminosilanes such as γ-anilopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3, 4-epoxycyclohexyl) epoxysilanes such as ethyltrimethoxysilane, chlorosilanes such as γ-chloropropyltrimethoxysilane, mercaptosilanes such as γ-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N- β- (N-vinylbenzylaminoethyl) -γ-aminopro Vinylsilane such as Le trimethoxysilane one or more selected from among acrylic silanes such as γ- methacryloxypropyl trimethoxysilane is used.

  In the component (B), the amount of surface treatment with novolak epoxy resin is not particularly limited, and all commercially available products subjected to general treatment can be used in the present invention. Usually, the adhesion amount is in the range of 0.1 to 3% of the total weight of the glass fiber. Further, in addition to the novolac epoxy resin, it may be surface-treated with other components such as bisphenol A type epoxy resin.

  In the present invention, the (B) glass fiber is used in an amount of 5 to 80 parts by weight, preferably 10 to 60 parts by weight, based on 100 parts by weight of the (A) polybutylene terephthalate resin. If the amount is less than 5 parts by weight, a sufficient reinforcing effect is not observed, and if it exceeds 80 parts by weight, the resin fluidity is inferior and the moldability may be deteriorated.

  The (C) carbodiimide compound used in the present invention is a compound having a carbodiimide group (—N═C═N—) in the molecule. Specifically, diisopropylcarbodiimide, dicyclohexylcarbodiimide, di-o-triylcarbodiimide, diphenylcarbodiimide, dioctyldecylcarbodiimide, di-2,6-isopropylphenylcarbodiimide, di-2,6-dimethylphenylcarbodiimide, di-p- Triylcarbodiimide, di-p-methoxyphenylcarbodiimide, p-phenylene-bis-di-o-triylcarbodiimide, p-phenylene-bis-dicyclohexylcarbodiimide, ethylene-bis-dicyclohexylcarbodiimide, ethylene-bis-diphenylcarbodiimide, etc. Mono or dicarbodiimide compounds, and poly (4,4′-diphenylmethanecarbodiimide), poly (3,3′-dimethyl-4,4′-diphenylmethane) Rubodiimide), poly (tricarbodiimide), poly (p-phenylenecarbodiimide), poly (m-phenylenecarbodiimide), poly (1,3-diisopropylphenylenecarbodiimide), poly (1-methyl-3,5-diisopropylphenylenecarbodiimide) And polycarbodiimide compounds such as poly (1,3,5-triethylphenylenecarbodiimide) and poly (triisopropylphenylenecarbodiimide). Two or more of these can be used in combination. Among these, dicyclohexylcarbodiimide, di-2,6-isopropylphenylcarbodiimide, di-2,6-dimethylphenylcarbodiimide, di-o-triylcarbodiimide, poly (4,4′-diphenylmethanecarbodiimide), poly (tricarbodiimide) ), Poly (phenylene carbodiimide), and poly (triisopropylphenylene carbodiimide) are suitable.

  In the present invention, the (C) carbodiimide compound is used in an amount of 0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the (A) polybutylene terephthalate resin. If the amount is less than 0.1 parts by weight, the effect is not sufficient, and if it exceeds 5 parts by weight, the fluidity is lowered, and gel components and carbides are likely to be generated at the time of compounding or molding.

  In addition, the (C) carbodiimide compound can be blended as a master batch using a resin as a matrix resin, and it is easy to use the master batch in terms of actual handling. A masterbatch made of polybutylene terephthalate resin is preferably used, but a masterbatch prepared with another resin may be used. In the case of a masterbatch with polybutylene terephthalate resin, (A) polybutylene terephthalate resin as the main component is introduced from the upstream material supply port so that it is within the range of the above blending amount, and the remaining polycrystal as a master batch is obtained. The (C) carbodiimide compound containing the butylene terephthalate resin is added simultaneously with (B) the glass fiber or thereafter.

  The resin composition produced by the production method of the present invention has good moldability. Therefore, in the present invention, for example, the resin composition can be melt-kneaded and easily molded by a conventional molding method such as extrusion molding or injection molding, and a molded product can be obtained efficiently. In particular, injection molding is preferred.

  In addition, the polybutylene terephthalate resin composition produced by the production method of the present invention is polymerizing one or more kinds of other thermoplastic resins, additives, organic fillers, inorganic fillers and the like as necessary. Alternatively, it can also be used as a composition supplemented and added after polymerization. Here, examples of the thermoplastic resin include polyester resins and polyester elastomers other than the polybutylene terephthalate of the present invention, polyolefin resins, polystyrene resins, polyamide resins, polycarbonates, polyacetals, polyarylene oxides, polyarylene sulfides, fluorine resins, and the like. Illustrated.

  As additives, conventionally known stabilizers such as ultraviolet absorbers and antioxidants, antistatic agents, flame retardants, flame retardant aids, colorants such as dyes and pigments, lubricants, plasticizers, lubricants, Examples include mold release agents and crystal nucleating agents.

  Examples of the inorganic filler include glass fibers other than the present invention, milled glass fibers, glass beads, glass flakes, silica, alumina fibers, zirconia fibers, potassium titanate fibers, carbon fibers, carbon black, graphite, calcium silicate, silicic acid. Silicates such as aluminum, kaolin, talc and clay, metal oxides such as iron oxide, titanium oxide, antimony oxide and alumina, carbonates and sulfates of metals such as calcium, magnesium and zinc, silicon carbide, silicon nitride, Examples thereof include boron nitride, and examples of the organic filler include high-melting point aromatic polyester fibers, liquid crystalline polyester fibers, aromatic polyamide fibers, fluororesin fibers, and polyimide fibers.

  In addition, when used as a molded product for electrical / electronic parts or automobile parts, etc., there are many cases where flame retardancy is required depending on the usage environment, and it is essential to add flame retardants and flame retardant aids. Many. As the flame retardant, known halogen-containing compound-based flame retardants such as brominated polycarbonate, brominated epoxy compound, brominated diphenyl, brominated diphenyl ether can be used, and antimony trioxide, antimony pentoxide, halogenated as flame retardant aids In addition to antimony compounds such as antimony, metal compounds containing zinc and bismuth, clayey silicates such as magnesium hydroxide, and the like can be used. Furthermore, it is also possible to use a non-halogen flame retardant for the recent environmental considerations.

  In the present invention, a method of adding a part of the resin component as a fine powder and mixing it with other components is a preferable method for achieving uniform blending of these components. Moreover, the filler etc. which were mentioned above can be added at arbitrary timings, and a desired composition can be obtained.

  Since the polybutylene terephthalate resin composition produced by the production method of the present invention is excellent in impact resistance and mechanical properties, it is suitable for molded articles for electric and electronic parts used in the automotive field and OA field. In particular, it is suitable for injection molded products such as connectors, switches, various sensors, board storage boxes and their peripheral parts, and housings.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.
Examples 1-7
With the raw material composition shown in Table 1, each component was melt-kneaded at 250 ° C. using a 30 mmφ twin screw extruder, pelletized, a test piece was prepared, and each evaluation was performed.

The twin-screw extruder has three raw material supply ports (referred to as X, Y, and Z from the upstream side to the downstream side in the extrusion direction), and all the polybutylene terephthalate and antioxidant are charged from the raw material supply port X. Carbodiimide was introduced from the same supply port Y as the glass fiber or from the supply port Z downstream of Y. The distance between XY and YZ is 50 cm and 20 cm, respectively.
Comparative Examples 1-9
With the raw material compositions shown in Table 2, test pieces were prepared in the same manner as in the above examples, and each evaluation was performed.

  Comparative Example 1 is an example where no carbodiimide is added.

  Comparative Examples 2, 3, and 7 are examples in which carbodiimide was introduced from the raw material supply port X simultaneously with polybutylene terephthalate.

  Further, Comparative Examples 4, 5, and 6 are examples in which glass fibers subjected to bisphenol A epoxy treatment instead of novolac epoxy treatment were used.

  Further, Comparative Examples 8 and 9 are examples in which ethylene / ethyl acrylate elastomer was used instead of carbodiimide.

  These results are shown in Tables 1-2.

Moreover, the detail of the used component and the measuring method of physical property evaluation are as follows.
(A) Polybutylene terephthalate: 500FP manufactured by Wintech Polymer Co., Ltd.
(B) Glass fiber
(B-1) Glass fiber treated with novolac epoxy; 13mmφ, loss on ignition 1.2%
(B'-1) Glass fiber treated with bisphenol A epoxy; 13mmφ, loss on ignition 0.7%
(C) Carbodiimide compound
(C-1) Polycarbodiimide; Starbucksol P manufactured by Rhein Chemie Japan
(C-2) Polybutylene terephthalate masterbatch of polycarbodiimide; 20% by weight of Starbucksol P manufactured by Rhein Chemie Japan
(D) Ethylene ethyl acrylate elastomer; NUC6570 manufactured by Nippon Unicar Co., Ltd.
Antioxidant: Irganox 1010 manufactured by Ciba Geigy Japan
<Charpy impact value, tensile strength, tensile elongation>
The obtained pellets were dried at 140 ° C. for 3 hours, and then injection molded at a molding temperature of 260 ° C. and a mold temperature of 80 ° C. The Charpy impact test pieces and tensile test pieces obtained by injection molding were evaluated according to the evaluation criteria defined in ISO 527 and 179.

  As shown in Table 1, the products of the present invention obtained good results in all of Charpy impact value, tensile strength, and tensile elongation.

  On the other hand, if carbodiimide is added simultaneously with polybutylene terephthalate, excellent physical properties cannot be obtained (Comparative Examples 2, 3, and 7).

  In addition, when glass fiber treated with bisphenol A epoxy is used, excellent physical properties cannot be obtained even by the method of the present invention (Comparative Examples 4, 5, and 6).

  Furthermore, when an ethylene / ethyl acrylate elastomer is used instead of carbodiimide, excellent physical properties cannot be obtained regardless of the difference in addition time (Comparative Examples 8 and 9).

Claims (6)

(A) A polybutylene terephthalate resin, (B) a glass fiber surface-treated with a novolac epoxy resin, and (C) a method for producing a polybutylene terephthalate resin composition containing a carbodiimide compound, comprising two or more raw material supply ports The component (A) is supplied from the raw material supply port on the upstream side in the extrusion direction of the twin screw extruder and the component (B) and the component (C) are simultaneously supplied from the downstream material supply port, or the twin screw extruder The component (A) is supplied from the raw material supply port upstream of the extrusion direction, the component (B) is supplied from the downstream material supply port, and the component (C) is supplied from the downstream material supply port. And then kneading and kneading the polybutylene terephthalate resin composition. The method for producing a polybutylene terephthalate resin composition according to claim 1, wherein the (C) carbodiimide compound is supplied as a master batch using (A) a polybutylene terephthalate resin as a matrix resin. The amount of the components (A), (B), (C) used is 100 / (5-80) / (0.1-5) in a weight ratio of (A) / (B) / (C). Or the manufacturing method of the polybutylene terephthalate resin composition of 2. The polybutylene terephthalate resin composition manufactured by the manufacturing method of any one of Claims 1-3. A molded article for electric / electronic parts, which is obtained by injection molding the polybutylene terephthalate resin composition according to claim 4. The molded product for electric / electronic parts according to claim 5, which is a connector, a switch, various sensors, a board storage box and its peripheral parts, or a housing.