Polybutylene terephthalate resin composition, method for producing the same, and molded article containing the same

Abstract

The present invention relates to a polybutylene terephthalate resin composition, a production method thereof, and a molded product containing the same. The polybutylene terephthalate resin composition according to the present invention has the effect of simultaneously improving the injection solidification speed and impact strength, which are in a trade-off relationship when materials used are changed, satisfying a balance of physical properties such as mechanical properties, fluidity, and heat resistance, and providing excellent product reliability and appearance quality.

Description

Technical Field

[0001] 〔Cross - reference to related applications〕 This application claims the benefit of priority based on Korean Patent Application No. 10 - 2022 - 0124293 filed on September 29, 2022, and all the contents disclosed in the literature of the Korean patent application are incorporated herein by reference in their entirety.

[0002] The present invention relates to a polybutylene terephthalate resin composition, a method for manufacturing the same, and a molded article including the same. More specifically, by changing the raw materials used, the injection solidification rate and impact strength, which are in a trade - off relationship, are simultaneously improved to satisfy the physical property balance such as mechanical properties, fluidity, heat - resistant properties, etc., and to provide a polybutylene terephthalate resin composition, a method for manufacturing the same, and a molded article including the same that can provide excellent product reliability and appearance quality.

Background Art

[0003] As a material for automotive parts, a method of using a polyester resin and an organic / inorganic injection solidification accelerator to increase the crystallinity for improving the injection solidification rate is widely used.

[0004] However, in order to increase the crystallinity by improving the solidification rate, there is a drawback that the impact strength decreases.

[0005] Moreover, recently, due to the miniaturization / thinning of electronic equipment parts, there is a tendency to require higher impact strength than before. Therefore, in the technology of increasing the crystallinity, further problems such as cracks occurring in the product have occurred.

[0006] Therefore, when a reinforcing agent is added for the purpose of reinforcing the impact strength, the impact strength is improved and the crack problem is solved, but the injection solidification rate is significantly reduced. That is, the injection solidification rate and the impact strength are in a trade - off relationship.

[0007] Therefore, there is a need to develop a material for automotive interior materials that can overcome such a trade-off relationship and efficiently improve the injection solidification speed and impact strength simultaneously.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] In order to solve the problems of the prior art as described above, the present invention not only reduces the cost by changing the material used, but also can be used as a non-painted product, so it is excellent in economy. At the same time, it improves the injection solidification speed and impact strength in a trade-off relationship, satisfies the physical property balance such as mechanical properties, fluidity, and heat resistance characteristics, and provides excellent product reliability and appearance quality. An object of the present invention is to provide a polybutylene terephthalate resin composition.

[0010] Another object of the present invention is to provide a molded product using the above polybutylene terephthalate resin composition.

[0011] The above object and other objects of the present invention can all be achieved by the present invention described below.

Means for Solving the Problems

[0012] In order to achieve the above object, the present invention 80 to 99% by weight of a base resin containing a polybutylene terephthalate resin having an intrinsic viscosity (η) exceeding 1.05 and a polybutylene terephthalate resin having an intrinsic viscosity (η) of 1.05 or less, and 0.01 to 10% by weight of a carboxy-reactive epoxy resin, and Provided is a polybutylene terephthalate resin composition characterized by containing 0.01 to 10% by weight of polybutadiene rubber.

[0013] The polybutylene terephthalate resin having an intrinsic viscosity (η) of 1.05 or less can contain a polybutylene terephthalate resin having an intrinsic viscosity of less than 0.9 and a polybutylene terephthalate resin having an intrinsic viscosity of more than 0.9 and 1.05 or less in a weight ratio of 30:70 to 60:40.

[0014] The polybutylene terephthalate resin having an intrinsic viscosity (η) of more than 1.05 can contain a polybutylene terephthalate resin having an intrinsic viscosity of more than 1.05 and 1.5 or less at 29 to 55% by weight based on 100% by weight of the total amount of all components (base resin, carboxy-reactive epoxy resin, polybutadiene rubber, and additive) constituting the polybutylene terephthalate resin composition.

[0015] The carboxy-reactive epoxy resin may be one or more selected from ethylene-n-butyl acrylate-glycidyl methacrylate copolymer, ethylene-glycidyl methacrylate copolymer, ethylene-acrylic acid ester-glycidyl methacrylate copolymer, ethylene-methyl acrylate-glycidyl methacrylate copolymer, ethylene-dimethacrylate-glycidyl methacrylate copolymer, ethylene-acrylate-glycidyl methacrylate copolymer, and ethylene-vinyl acetate-glycidyl methacrylate copolymer.

[0016] The carboxy-reactive epoxy resin can contain 1 to 15% by weight of units derived from glycidyl methacrylate.

[0017] The polybutadiene rubber may have a bulk density of 0.25 g / cc or more as measured in accordance with ASTM D1895.

[0018] The polybutadiene rubber may have an Izod impact strength (-30°C, 1 / 4'' thickness) of 10 kg / cm·cm or more as measured in accordance with ASTM D256, and may also have an Izod impact strength (23°C, 1 / 4'' thickness) of 50 kg / cm·cm or more.

[0019] The polybutadiene rubber may have 3% or less of the fraction passing through #20 mesh in all particles, based on 100% of the total number of all particles.

[0020] The polybutylene terephthalate resin composition may contain an injection solidification accelerator. Specific examples include inorganic injection solidification accelerators such as talc, wollastonite, and mica, or ethylene acrylate-based compounds.

[0021] The injection solidification accelerator may be contained in an amount of 0.01 to 1% by weight based on 100% by weight of the total amount of all components (base resin, carboxy-reactive epoxy resin, polybutadiene rubber, and additives) constituting the polybutylene terephthalate resin composition.

[0022] The polybutylene terephthalate resin composition may contain one or more additives selected from lubricants, antioxidants, and colorants.

[0023] Further, the present invention provides 29 to 55% by weight of a polybutylene terephthalate resin having an intrinsic viscosity (η) of more than 1.05 and 1.5 or less, 0 to 68% by weight of a polybutylene terephthalate resin having an intrinsic viscosity (η) of more than 0.9 and 1.05 or less, 0 to 50% by weight of a polybutylene terephthalate resin having an intrinsic viscosity (η) of 0.7 or more and less than 0.9, 0.01 to 10% by weight of a carboxy-reactive epoxy resin, 0.01 to 10% by weight of a polybutadiene rubber, and 0.01 to 1% by weight of an injection solidification accelerator.

[0024] Also, the present invention i) 29 to 54% by weight of a polybutylene terephthalate resin having an intrinsic viscosity (η) of more than 1.05 and 1.5 or less, ii) 35 to 68% by weight of a polybutylene terephthalate resin having an intrinsic viscosity (η) of more than 0.9 and 1.05 or less, or 41 to 49% by weight of a polybutylene terephthalate resin having an intrinsic viscosity (η) of 0.7 or more and less than 0.9, iii) 0.01 to 10% by weight of a carboxy-reactive epoxy resin, iv) 0.01 to 10% by weight of a polybutadiene rubber, v) 0 to 1% by weight of an injection curing accelerator, and provides a polybutylene terephthalate resin composition characterized in that the total weight of the polybutylene terephthalate resins in i) and ii) is 80 to 99% by weight.

[0025] Also, the present invention provides a method for producing a polybutylene terephthalate resin composition, which includes the steps of charging 80 to 99% by weight of a base resin containing a polybutylene terephthalate resin having an intrinsic viscosity (η) of more than 1.05 and a polybutylene terephthalate resin having an intrinsic viscosity (η) of 1.05 or less, 0.01 to 10% by weight of a carboxy-reactive epoxy resin, 0.01 to 10% by weight of a polybutadiene rubber, and 0 to 1% by weight of an injection curing accelerator into an extruder, and performing melt kneading and extrusion.

[0026] The injection curing accelerator can be included in the range of 0.01 to 1% by weight based on 100% by weight of the total amount of all components (base resin, carboxy-reactive epoxy resin, polybutadiene rubber, and additives) constituting the polybutylene terephthalate resin composition.

[0027] Also, the present invention provides a molded article produced by including the aforementioned polybutylene terephthalate resin composition.

[0028] The molded article may be an automobile part.

[0029] The automotive parts may be connectors, carburetor parts, fenders, spoilers, spark plug terminal plates, oil supply system parts, dashboards, automotive igniters, accelerators, and clutch pedals.

Advantages of the Invention

[0030] The polybutylene terephthalate resin composition according to the present invention contains a polybutylene terephthalate resin having a specific intrinsic viscosity, a polybutadiene rubber, and a carboxy-reactive epoxy resin, and can be formed into a molded article.

[0031] In addition, the molded article produced from the composition simultaneously improves the injection solidification rate and impact strength in a trade-off relationship, satisfies the physical property balance with mechanical properties, fluidity, etc., and is excellent in moldability, so that there is an effect of improving the appearance quality.

[0032] Therefore, the polybutylene terephthalate resin composition according to the present invention can be applied to the field of molded articles related to fastening parts such as connectors that require this.

Brief Description of the Drawings

[0033]

Figure 1

Best Mode for Carrying Out the Invention

[0034] Hereinafter, in order to assist in the understanding of the present invention, the present invention will be described in more detail.

[0035] The terms and words used in this specification and the claims should not be construed as being limited to the ordinary or dictionary meanings, but should be construed in a meaning and concept that conforms to the technical idea of the present invention, taking into account that the inventor can appropriately define the concept of the terms in order to explain the invention in the best way.

[0036] In this description, unless otherwise defined, the meaning of "comprising" can be defined as "polymerized and produced while comprising", "polymerized while comprising", or "comprising as a unit derived therefrom".

[0037] Unless otherwise specified, all numbers, values, and / or expressions used in this description to represent the amounts of components, reaction conditions, polymer compositions, and formulations are to be understood as being modified in all cases by the term "about", since such numbers are approximate values that reflect the various uncertainties of the measurements that occur in obtaining such values among other things. Also, when a numerical range is disclosed in this description, such range is continuous and, unless otherwise indicated, includes all values from the minimum value to the maximum value including the said maximum value. Further, when such range refers to integers, unless otherwise specified, it includes all integers from the minimum value to the maximum value including the said maximum value.

[0038] In this description, when a range is described with respect to a variable, the said variable is to be understood as including all values within the described range including the described end point of the range. For example, the range of "5 to 10" includes not only the values of 5, 6, 7, 8, 9, and 10, but also any sub-ranges such as 6 to 10, 7 to 10, 6 to 9, 7 to 9, etc., and any value between the appropriate integers within the category of the described range such as 5.5 to 8.5, and 6.5 to 9. Also, the range of 10 to 30% includes not only the values of 10%, 11%, 12%, 13%, etc. and all integers up to 30%, but also any value between the appropriate integers within the category of the described range such as 10.5%, 15.5%, 25.5%, etc.

[0039] The term "injection solidification accelerator" used in this description refers to a substance that is introduced to shorten the solidification time during injection molding, unless otherwise specified. For reference, the solidification time can vary depending on the design and size of the mold of the injection machine even when using the same material.

[0040] In this description, unless otherwise specified, the melt index may be the melt index measured at 250 °C with a load of 2.16 kg in accordance with ISO 1133.

[0041] The inventors of the present invention have used a polybutylene terephthalate resin composition containing a polybutylene terephthalate resin having a specific intrinsic viscosity, a polybutadiene rubber, and a carboxy-reactive epoxy resin to manufacture an automotive interior material. They have confirmed that the injection solidification rate and impact strength, which are in a trade-off relationship, are simultaneously improved, satisfying the physical property balance such as mechanical properties, fluidity, and heat resistance characteristics, and providing excellent product reliability and appearance quality. While satisfying the physical property balance such as mechanical properties, fluidity, and heat resistance characteristics of the present invention, a material for an automotive interior material has been completed as a paintless product excellent in moldability and appearance quality.

[0042] A polybutylene terephthalate resin composition according to an embodiment of the present invention includes 80 to 99% by weight of a base resin including a polybutylene terephthalate resin having an intrinsic viscosity (η) exceeding 1.05 and a polybutylene terephthalate resin having an intrinsic viscosity (η) of 1.05 or less; 0.01 to 10% by weight of a carboxy-reactive epoxy resin; and 0.01 to 10% by weight of a polybutadiene rubber.

[0043] As another example, the polybutylene terephthalate resin composition may contain an injection solidification accelerator in an amount of 1% by weight or less.

[0044] Hereinafter, the components constituting the polybutylene terephthalate resin composition will be specifically described.

[0045] Base resin The base resin according to an embodiment of the present invention uses a polybutylene terephthalate resin, imparts moldability to a polybutylene terephthalate resin composition containing the same, and imparts chemical resistance to a molded product manufactured using the same.

[0046] The above-mentioned polybutylene terephthalate resin is a crystalline resin, and since it has a crystallized structure while preventing the penetration of chemical agents flowing in from the outside, during injection molding, the fluidity of the polybutylene terephthalate resin composition containing this resin is improved, and the appearance quality is made excellent.

[0047] The intrinsic viscosity (η) of the above-mentioned polybutylene terephthalate resin is characterized by simultaneously including a type exceeding 1.05 and a type of 1.05 or less. In this case, the injection solidification rate and impact strength, which are in a trade-off relationship, can be improved simultaneously.

[0048] As a specific example, the intrinsic viscosity (η) of the above-mentioned polybutylene terephthalate resin is characterized by simultaneously including one type exceeding 1.05 and less than or equal to 1.5, and one type selected from a type with an intrinsic viscosity (η) exceeding 0.9 and less than or equal to 1.05 and a type with an intrinsic viscosity (η) less than 0.9. In this case, an appropriate physical property balance between the injection solidification rate and impact strength, which are in a trade-off relationship, can be provided.

[0049] In this description, unless otherwise specified, the intrinsic viscosity is the value measured at 20 °C using an Ubbelohde viscometer for the filtrate obtained by completely dissolving the sample to be measured in a methylene chloride solvent at a concentration of 0.05 g / ml and then filtering it using a filter.

[0050] The content of the above-mentioned polybutylene terephthalate resin is, for example, 80 to 99% by weight, specifically 85 to 99% by weight, preferably 90 to 99% by weight, based on 100% by weight of the total amount of all components (base resin, carboxy-reactive epoxy resin, polybutadiene rubber, and additives) constituting the polybutylene terephthalate resin composition. If it is less than the above-mentioned range, there is a drawback that the rigidity and heat resistance characteristics of the molded product manufactured using the polybutylene terephthalate resin composition containing this resin decrease. If it exceeds the above-mentioned range, there is a drawback that cracks occur in the molded product manufactured using the polybutylene terephthalate resin composition containing this resin.

[0051] The polybutylene terephthalate resin with an inherent viscosity (η) of less than 0.9 and the polybutylene terephthalate resin with an inherent viscosity of more than 0.9 and less than or equal to 1.05 can be included, for example, in a weight ratio of 30:70 to 60:40, specifically in a weight ratio of 32:68 to 68:32, preferably in a weight ratio of 35:65 to 65:35. In this case, the balance of physical properties such as mechanical properties, fluidity, and heat resistance can be satisfied.

[0052] The inherent viscosity of the polybutylene terephthalate resin with an inherent viscosity (η) of more than 1.05 and less than or equal to 1.5 can be, for example, 1.1 to 1.4, specifically 1.1 to 1.3, preferably 1.1 to 1.2. In this case, the balance of physical properties such as mechanical properties, fluidity, and heat resistance can be satisfied.

[0053] The inherent viscosity of the polybutylene terephthalate resin with an inherent viscosity (η) of more than 0.9 and less than or equal to 1.05 can be, for example, 0.91 to 1.05, specifically 0.95 to 1.05, preferably 0.98 to 1.02. In this case, the balance of physical properties such as mechanical properties, fluidity, and heat resistance can be satisfied.

[0054] The inherent viscosity of the polybutylene terephthalate resin with an inherent viscosity (η) of 0.7 or more and less than 0.9 can be, for example, 0.7 to 0.85, specifically 0.75 to 0.85, preferably 0.8 to 0.85. In this case, the balance of physical properties such as mechanical properties, fluidity, and heat resistance can be satisfied.

[0055] The polybutylene terephthalate resins having the respective inherent viscosities described above are not particularly limited, and they may be produced and used through methods known in the art or commercially available substances may be used.

[0056] The polybutylene terephthalate resin having an inherent viscosity (η) of more than 1.05 and 1.5 or less may be contained in an amount of, for example, 29 to 55% by weight, specifically 30 to 55% by weight, preferably 32 to 53% by weight, based on 100% by weight of the total amount of all components (base resin, carboxy-reactive epoxy resin, polybutadiene rubber, and additive) constituting the polybutylene terephthalate resin composition. In this case, a balance of physical properties such as mechanical properties, fluidity, and heat resistance can be satisfied.

[0057] The polybutylene terephthalate resin having an inherent viscosity (η) of more than 0.9 and 1.05 or less may be contained in an amount of, for example, 0 to 68% by weight, specifically 40 to 68% by weight, preferably 35 to 68% by weight, more preferably 40 to 65% by weight, still more preferably 40 to 60% by weight, based on 100% by weight of the total amount of all components (base resin, carboxy-reactive epoxy resin, polybutadiene rubber, and additive) constituting the polybutylene terephthalate resin composition. In this case, a balance of physical properties such as mechanical properties, fluidity, and heat resistance can be satisfied.

[0058] The polybutylene terephthalate resin having an inherent viscosity (η) of 0.7 or more and less than 0.9 may be contained in an amount of, for example, 0 to 50% by weight, specifically 30 to 50% by weight, preferably 40 to 50% by weight, more preferably 40 to 48% by weight, still more preferably 40 to 45% by weight, based on 100% by weight of the total amount of all components (base resin, carboxy-reactive epoxy resin, polybutadiene rubber, and additive) constituting the polybutylene terephthalate resin composition. In this case, a balance of physical properties such as mechanical properties, fluidity, and heat resistance can be satisfied.

[0059] Carboxy-reactive epoxy resin The term "carboxy-reactive epoxy resin" used in this description refers to an epoxy-functional alkylene (meth)acrylic copolymer formed from an epoxy-functional (meth)acrylic monomer and an alkylene, unless otherwise specified.

[0060] As used herein, the term “(meth)acryl” includes both acrylic and methacrylic monomers, unless otherwise specified, and the term “(meth)acrylate” includes both acrylate and methacrylate monomers.

[0061] Specific examples of the epoxy-functional (meth)acrylic monomer can include those containing a 1,2-epoxy group such as glycidyl acrylate and glycidyl methacrylate.

[0062] The carboxy-reactive epoxy resin used herein may, as specific examples, be one or more selected from ethylene-n-butyl acrylate-glycidyl methacrylate copolymer, ethylene-glycidyl methacrylate copolymer, ethylene-acrylic acid ester-glycidyl methacrylate copolymer, ethylene-methyl acrylate-glycidyl methacrylate copolymer, ethylene-dimethacrylate-glycidyl methacrylate copolymer, ethylene-acrylate-glycidyl methacrylate copolymer, and ethylene-vinyl acetate-glycidyl methacrylate copolymer.

[0063] The carboxy-reactive epoxy resin described herein may, as an example, be a copolymer polymerized to contain 1 to 15% by weight or 3 to 10% by weight of glycidyl methacrylate units, 60 to 74% by weight or 63 to 74% by weight of ethylene units, and 20 to 30% by weight or 25 to 30% by weight of n-butyl acrylate. At this time, if the content of glycidyl methacrylate units is too high, there is a drawback that injection products manufactured using a polybutylene terephthalate resin composition containing this cause a decrease in the fluidity of the composition and inhibit the appearance quality.

[0064] The content of the carboxy-reactive epoxy resin may be 0.01 to 10% by weight, preferably 0.1 to 4% by weight, more preferably 1 to 4% by weight, based on 100% by weight of the total components (base resin, carboxy-reactive epoxy resin, polybutadiene rubber, and additive) constituting the composition. If the content of the carboxy-reactive epoxy resin is too high outside the above range, there is a problem of gas generation in the injection molding of the molded product manufactured using the polybutylene terephthalate resin composition containing this, and there is a drawback of inhibiting the appearance quality.

[0065] Polybutadiene rubber The polybutadiene rubber according to an embodiment of the present invention can be of a type that provides impact strength during injection molding of a molded product manufactured using the polybutylene terephthalate resin composition described herein.

[0066] In one embodiment of the present invention, the polybutadiene rubber may have an Izod impact strength (-30°C, 1 / 4'' thickness) measured according to ASTM D256 of, for example, 10 kg / cm.cm or more, and at the same time, an Izod impact strength (23°C, 1 / 4'' thickness) of, for example, 50 kg / cm.cm or more. In this case, a balance of physical properties such as mechanical properties, fluidity, and heat resistance can be satisfied.

[0067] As a specific example, the polybutadiene rubber may have an Izod impact strength (-30°C, 1 / 4'' thickness) measured according to ASTM D256 of, for example, 10 to 100 kg / cm.cm, and at the same time, an Izod impact strength (23°C, 1 / 4'' thickness) of, for example, 50 to 150 kg / cm.cm. In this case, a balance of physical properties such as mechanical properties, fluidity, and heat resistance can be satisfied.

[0068] The linear type and branched type of polybutadiene contained in the polybutadiene rubber may be adjusted to a weight ratio of 25:75 to 90:10.

[0069] The linear type and branched type of the polybutadiene may be premixed in a liquid phase at a weight ratio of 50:75 to 50:25 and then solidified (solid phase).

[0070] The linear type of the polybutadiene is obtained by polymerizing 1,3-butadiene or a butadiene derivative using a transition metal Ziegler-Natta catalyst in the presence of a nonpolar solvent. As the transition metal Ziegler-Natta catalyst, it may be obtained by including a nickel catalyst composed of a nickel salt, an organoaluminum, and a fluorinated compound, and a dialkyl zinc compound represented by the following Chemical Formula 1 as a molecular weight regulator.

[0071] Chemical Formula 1: R1-Zn-R2 (In the above formula, R1 and R2 are the same or different alkyl groups having 1 to 5 carbon atoms)

[0072] The branched type in the polybutadiene is obtained by polymerizing 1,3-butadiene or a butadiene derivative using a transition metal Ziegler-Natta catalyst in the presence of a nonpolar solvent. As the transition metal Ziegler-Natta catalyst, a nickel catalyst composed of a nickel salt, a fluorinated compound, an organoaluminum, and an aluminoxane may be used, and the reactivity of the organoaluminum and the aluminoxane may be adjusted.

[0073] The nickel salt may be a carboxylate having a saturated, unsaturated, cyclic or linear structure with 8 to 20 carbon atoms. As specific examples, the carboxylate may be nickel octoate, nickel versatate or nickel naphthenate.

[0074] The 1,3-butadiene or butadiene derivative may be one or more selected from 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, myrcene and derivatives thereof.

[0075] The non-polar solvent may be one or more selected from pentane, hexane, isopentane, heptane, octane, isooctane, cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane, benzene, toluene, ethylbenzene, and xylene.

[0076] In one embodiment of the present invention, the polybutadiene rubber may have, as an example, the amount passing through #20 mesh in all particles being 3% or less, as a specific example, 0.01 to 3%, preferably 0.1 to 3% in 100% of the total number of all particles. In this case, the balance of physical properties such as mechanical properties, fluidity, and heat resistance can be satisfied.

[0077] The polybutadiene rubber described herein may be, as an example, 0.01 to 10% by weight, preferably 0.1 to 5% by weight, more preferably 0.1 to 5% by weight, still more preferably 1 to 5% by weight, and most preferably 2 to 5% by weight based on 100% by weight of the total of all components (base resin, carboxy-reactive epoxy resin, polybutadiene rubber, and additive) constituting the composition. In this case, it is possible to overcome the drawback of delaying the solidification rate instead of imparting appropriate impact resistance to a molded product manufactured using the polybutylene terephthalate resin composition containing this.

[0078] The butadiene resin is not particularly limited, and it may be manufactured and used through methods known in the art, or commercially available substances may be used. As an example, EM538 of LG Chem. etc. may be mentioned.

[0079] Injection curing accelerator The injection solidification accelerator according to one embodiment of the present invention can be included for shortening the solidification rate during injection molding of a molded product manufactured using a polybutylene terephthalate resin composition to provide product reliability, such as improving its crystallinity.

[0080] As an example, the injection curing accelerator can be an inorganic injection curing accelerator such as talc, wollastonite, and mica, or an organic injection curing accelerator such as an ethylene acrylate-based compound. When the organic injection curing accelerator is used together with the polybutadiene rubber described above, it can maintain a high impact strength because it has a fast curing speed characteristic and a low reduction in impact, thus reducing the occurrence of cracks in parts and being easy to apply to small / thin film materials.

[0081] As an example, the ethylene acrylate-based compound can include types of ethylene compounds and unsaturated acrylates.

[0082] In one embodiment of the present invention, the ethylene acrylate-based compound may have a bulk density of 0.25 g / cc or more measured in accordance with ASTM D1895. In this case, it can satisfy the physical property balance such as mechanical properties, fluidity, and heat resistance characteristics.

[0083] As an example, the ethylene acrylate-based compound described herein may be a copolymer polymerized to contain 1 to 15% by weight or 3 to 10% by weight of ethylene units, 60 to 74% by weight or 63 to 74% by weight of acrylate units, and 20 to 30% by weight or 25 to 30% by weight of acrylic acid units. At this time, if the content of ethylene units is too high, there is a disadvantage that injection products manufactured using a polybutylene terephthalate resin composition containing this cause a decrease in the fluidity of the composition and inhibit the appearance quality.

[0084] The content of the ethylene acrylate-based compound may be, for example, 0.01 to 1% by weight, preferably 0.01 to 0.8% by weight, and more preferably 0.1 to 0.5% by weight based on 100% by weight of the total of all components (base resin, carboxy-reactive epoxy resin, polybutadiene rubber, and additives) constituting the composition. If the content of the ethylene acrylate-based compound is too high outside the above range, there is a disadvantage that cracks are generated on the surface of molded products manufactured using a polybutylene terephthalate resin composition containing this.

[0085] The injection curing accelerator is not particularly limited, and it may be manufactured and used through methods known in the art or commercially available substances may be used. As an example, the PTW series of Dupont can be mentioned.

[0086] Additive The polybutylene terephthalate resin composition according to an embodiment of the present invention can contain appropriate additives for improving its fluidity and the like.

[0087] As an example, the additive may be 0.01 to 10% by weight, preferably 0.1 to 8% by weight, more preferably 0.1 to 5% by weight, still more preferably 1 to 5% by weight, and most preferably 1 to 3% by weight based on 100% by weight of the total components (base resin, carboxy-reactive epoxy resin, polybutadiene rubber, and additive) constituting the composition.

[0088] The polybutylene terephthalate resin composition according to an embodiment of the present invention can contain appropriate additives for improving its fluidity and the like.

[0089] As an example, the additive may be 0.01 to 10% by weight, preferably 0.1 to 8% by weight, more preferably 0.1 to 5% by weight, still more preferably 1 to 5% by weight, and most preferably 1 to 3% by weight based on 100% by weight of the total components (base resin, carboxy-reactive epoxy resin, polybutadiene rubber, and additive) constituting the composition. If it is less than the above-mentioned range, there is a drawback that the solidification rate of the molded product manufactured using the polybutylene terephthalate resin composition containing this becomes slow and cracks occur. If it exceeds the above-mentioned range, there is a drawback that the rigidity and heat resistance characteristics of the molded product manufactured using the polybutylene terephthalate resin composition containing this decrease.

[0090] The additive can include, for example, one or more selected from lubricants, antioxidants, and colorants.

[0091] The lubricant is not particularly limited as long as it can ensure the ease of removal of the injection screw and the fluidity for manufacturing a molded product from the polybutylene terephthalate resin composition containing the same.

[0092] The lubricant is not particularly limited as long as it can be used in the present invention and can ensure the above characteristics, but preferably can include polyethylene-based wax.

[0093] The lubricant, as an example, is 0.01 to 10% by weight, preferably 0.1 to 3% by weight, more preferably 0.1 to 2% by weight, still more preferably 0.1 to 1% by weight, and most preferably 0.1 to 0.5% by weight based on 100% by weight of the total of all components (base resin, carboxy-reactive epoxy resin, polybutadiene rubber, and additive) constituting the composition. If the content of the lubricant is too much outside the above range, there are drawbacks such as unevenness on the surface of the molded product manufactured using the polybutylene terephthalate resin composition containing the same, which inhibits the appearance quality.

[0094] As long as the lubricant does not adversely affect the polybutylene terephthalate resin composition of the present invention, various known types can be used. Among commercially available substances, a polyethylene compound with the product name LC102N can be typically used.

[0095] The antioxidant is not particularly limited as long as it can prevent the modification of the molded product manufactured using the polybutylene terephthalate resin composition containing the same due to high temperature.

[0096] The antioxidant is not particularly limited as long as the above characteristics can be ensured. As an example, it can include a primary antioxidant, a secondary antioxidant, or both. In this case, it can prevent oxidation due to heat during the extrusion process and has the effect of excellent mechanical properties.

[0097] The primary antioxidant and the secondary antioxidant may be included in a weight ratio of 1:0.5 to 1.5, preferably 1:0.7 to 1.2. In this case, it has the effect of providing processability and physical property balance.

[0098] The primary antioxidant may be a phenolic antioxidant. As an example, it can include a hindered phenolic stabilizer having a crystallization temperature (Tm) of 110 to 130 °C. As specific examples, it can include tetrakis [ethylene-3-(3,5-di-t-butyl-hydroxyphenyl) propionate], octadecyl 3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate, or a combination thereof.

[0099] The phenolic antioxidant may be, for example, 0.01 to 10% by weight, preferably 0.01 to 3% by weight, more preferably 0.01 to 2% by weight, still more preferably 0.01 to 1% by weight, and most preferably 0.05 to 0.5% by weight, based on 100% by weight of the total components (base resin, carboxy-reactive epoxy resin, polybutadiene rubber, and additives) constituting the composition. If the content of the phenolic antioxidant is too high, there is a drawback that problems such as uneven appearance occur on the surface of the molded product manufactured using the polybutylene terephthalate resin composition containing it, which hinders the appearance quality.

[0100] The secondary antioxidant may be a phosphorus-based antioxidant. As an example, it can include a phosphite-based antioxidant. As specific examples, it can include tris-(2,4-di-tert-butylphenyl) phosphite, di-(2,4-di-t-butylphenyl) pentaerythritol diphosphite, or a combination thereof.

[0101] The phosphorus-based antioxidant, as an example, is 0.01 to 10% by weight, preferably 0.01 to 3% by weight, more preferably 0.01 to 2% by weight, still more preferably 0.01 to 1% by weight, and most preferably 0.1 to 0.5% by weight based on 100% by weight of the total components (base resin, carboxy-reactive epoxy resin, polybutadiene rubber, and additives) constituting the composition. If the content of the phosphorus-based antioxidant is too high, there is a drawback that unevenness or other appearance problems occur on the surface of a molded article produced using the polybutylene terephthalate resin composition containing the same, which inhibits the appearance quality.

[0102] The antioxidant can be used in a variety of known types as long as it does not adversely affect the polybutylene terephthalate resin composition of the present invention. Among commercially available substances, typically, the bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite compound with the product name Songnox6260 as a secondary antioxidant and the pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) compound with the product name IR1010 as a primary antioxidant can be used respectively, but it is not limited thereto.

[0103] The colorant according to the present invention may be a colorant including a pigment or a dye.

[0104] The pigment may be an inorganic pigment, for example.

[0105] The inorganic pigment may be, for example, one or more selected from the group consisting of metal compounds such as Ti, Pb, Fe, Cr and carbon black. The metal compound is preferably a metal oxide or a metal hydroxide. Specific examples of the inorganic pigment include TiO2 as a white inorganic pigment, Zinc Oxide; carbon black and graphite as black inorganic pigments; IOR, Cadmium Red, and Red Lead (Pb3O4) as red inorganic pigments; Chrome Yellow, Zinc Chromate, and Cadmium Y. as yellow inorganic pigments; and one or more selected from the group consisting of Chrome Green and Zinc Green as green inorganic pigments. The most preferred inorganic pigment may be carbon black, which is a black inorganic pigment.

[0106] The colorant may be, for example, 0.01 to 10 parts by weight, preferably 0.01 to 3 parts by weight, more preferably 0.1 to 3 parts by weight, and even more preferably 0.5 to 3 parts by weight, based on 100 parts by weight in total of all components (base resin, carboxy-reactive epoxy resin, polybutadiene rubber and additives) constituting the composition. If the content of the colorant is too high, there is a drawback that it inhibits the crack quality of the molded product manufactured using the polybutylene terephthalate resin composition containing the same.

[0107] Optionally, a hydrolysis resistance inhibitor can be further included.

[0108] As long as it does not adversely affect the polybutylene terephthalate resin composition of the present invention, various known types of the hydrolysis resistance inhibitor can be used. Among commercially available substances, an organic phosphate compound such as sodium dihydrogen phosphate with the chemical formula NaH2PO4 can be used typically.

[0109] The hydrolysis resistance inhibitor may, for example, be in an amount of 0.01 to 5% by weight, preferably 0.1 to 3% by weight, more preferably 0.1 to 2% by weight, still more preferably 0.1 to 1% by weight, and most preferably 0.1 to 0.5% by weight, based on 100% by weight of all components (base resin, carboxy-reactive epoxy resin, polybutadiene rubber, and additives) constituting the composition. If the content of the hydrolysis resistance inhibitor is too high outside the above range, there are drawbacks such as uneven appearance problems on the surface of molded articles produced using the polybutylene terephthalate resin composition containing the same, which inhibit the appearance quality.

[0110] Polybutylene terephthalate resin composition The polybutylene terephthalate resin composition according to an embodiment of the present invention includes 80 to 99% by weight of a base resin containing a polybutylene terephthalate resin having an intrinsic viscosity (η) of more than 1.05 and a polybutylene terephthalate resin having an intrinsic viscosity (η) of 1.05 or less, 0.01 to 10% by weight of a carboxy-reactive epoxy resin, 0.01 to 10% by weight of a polybutadiene rubber, and 0 to 1% by weight of an injection solidification accelerator. In this case, the injection solidification rate and the impact strength can be improved simultaneously, satisfying the physical property balance such as mechanical physical properties, fluidity, and heat resistance characteristics, and providing excellent product reliability and appearance quality.

[0111] The polybutylene terephthalate resin composition according to another embodiment of the present invention includes 29 to 55% by weight of a polybutylene terephthalate resin having an intrinsic viscosity (η) of more than 1.05 and 1.5 or less, 0 to 68% by weight of a polybutylene terephthalate resin having an intrinsic viscosity (η) of more than 0.9 and 1.05 or less, 0 to 50% by weight of a polybutylene terephthalate resin having an intrinsic viscosity (η) of 0.7 or more and less than 0.9, 0.01 to 10% by weight of a carboxy-reactive epoxy resin, 0.01 to 10% by weight of a polybutadiene rubber, and 0 to 1% by weight of an injection solidification accelerator. In this case, the injection solidification rate and the impact strength can be improved simultaneously, satisfying the physical property balance such as mechanical physical properties, fluidity, and heat resistance characteristics, and providing excellent product reliability and appearance quality, so it is suitable for application as a molded article.

[0112] The polybutylene terephthalate resin composition according to still another embodiment of the present invention comprises: i) 29 to 54% by weight of a polybutylene terephthalate resin having an intrinsic viscosity (η) of more than 1.05 and not more than 1.5; ii) 35 to 68% by weight of a polybutylene terephthalate resin having an intrinsic viscosity (η) of more than 0.9 and not more than 1.05, or 41 to 49% by weight of a polybutylene terephthalate resin having an intrinsic viscosity (η) of 0.7 or more and less than 0.9; iii) 0.01 to 10% by weight of a carboxy-reactive epoxy resin; iv) 0.01 to 10% by weight of a polybutadiene rubber; and v) 0 to 1% by weight of an injection solidification accelerator, and the total weight of the polybutylene terephthalate resins in i) and ii) is 80 to 99% by weight. In this case, the injection solidification rate and the impact strength are improved simultaneously, satisfying the physical property balance such as mechanical properties, fluidity, and heat resistance characteristics, and excellent product reliability and appearance quality can be provided, so it is suitable for application as a molded product.

[0113] The polybutylene terephthalate resin composition of the present invention may have a melt flow index (250 °C, 2.16 kgf) measured in accordance with ISO 1133 of, for example, 10 g / 10 min or more, and specifically 10 to 30 g / 10 min.

[0114] The polybutylene terephthalate resin composition of the present invention may have a tensile strength measured in accordance with ISO 527 of, for example, 45 MPa or more, and specifically 45 to 50 MPa.

[0115] The polybutylene terephthalate resin composition of the present invention may have an elongation at break measured in accordance with ISO 527 of, for example, 15% or more, and specifically 20 to 85%.

[0116] The polybutylene terephthalate resin composition of the present invention may have an Izod impact strength (23 °C, notch) measured in accordance with ISO 180 of, for example, 7 kJ / m 2 , and specifically 7.8 to 10 kJ / m 2 .

[0117] The polybutylene terephthalate resin composition of the present invention may have a heat distortion temperature measured under a load of 0.45 MPa in accordance with ISO 75 of 100 °C or higher, for example, and may be 100 to 130 °C as a specific example.

[0118] The polybutylene terephthalate resin composition of the present invention may have a heat distortion temperature measured under a high load of 1.8 MPa in accordance with ISO 75 of 40 °C or higher, for example, and may be 45 to 55 °C as a specific example.

[0119] The polybutylene terephthalate resin composition of the present invention may have a flexural modulus measured in accordance with ISO 178 of 1700 MPa or higher, for example, and may be 1750 to 2100 MPa as a specific example.

[0120] The polybutylene terephthalate resin composition of the present invention may have a flexural strength measured in accordance with ISO 178 of 60 MPa or higher, for example, and may be 64 to 80 MPa as a specific example.

[0121] Method for producing polybutylene terephthalate resin composition Hereinafter, the manufacturing method of the polybutylene terephthalate resin composition of the present invention will be described. In describing the manufacturing method of the polybutylene terephthalate resin composition of the present invention, all of the contents of the above-described polybutylene terephthalate resin composition are included.

[0122] The manufacturing method of the polybutylene terephthalate resin composition described herein includes, for example, steps of charging 80 to 99% by weight of a base resin containing a polybutylene terephthalate resin having an intrinsic viscosity (η) exceeding 1.05 and a polybutylene terephthalate resin having an intrinsic viscosity (η) of 1.05 or less, 0.01 to 10% by weight of a carboxy-reactive epoxy resin, 0.01 to 10% by weight of a polybutadiene rubber, and 0 to 1% by weight of an injection solidification accelerator into an extruder, and melt-kneading and extruding them.

[0123] The above-mentioned injection curing accelerator can contain an ethylene acrylate-based compound in the range of 0.01 to 1% by weight based on 100% by weight of the total amount of all components (base resin, carboxy-reactive epoxy resin, polybutadiene rubber, and additives) constituting the polybutylene terephthalate resin composition.

[0124] As an example, the melt-kneading step can include the other additives described above.

[0125] As an example, the step of melt-kneading and extruding may be performed using one or more selected from the group consisting of a single-screw extruder, a twin-screw extruder, and a Banbury mixer. Preferably, it is a twin-screw extruder. Using this, after uniformly mixing the composition, it can be extruded to obtain, for example, a pelletized polybutylene terephthalate resin composition. In this case, there is an effect of excellent mechanical properties, thermal properties, plating adhesion, and appearance quality.

[0126] The step of manufacturing pellets using the above-mentioned extrusion kneader can be performed, for example, at an extrusion temperature of 250 to 300°C, a supply rate (Flow ratio, F / R) of 50 to 90 kg / hr, and a screw rotation speed of 200 to 490 rpm. Preferably, it can be performed at an extrusion temperature of 250 to 270°C, an F / R of 50 to 90 kg / hr, and a screw rotation speed of 250 to 350 rpm.

[0127] After extruding the polybutylene terephthalate resin composition, it can include a step of injecting at an injection temperature of 240 to 280°C, specifically 250 to 270°C, a mold temperature of 40 to 80°C, specifically 50 to 70°C, and an injection speed of 10 to 50 mm / sec, specifically 20 to 40 mm / sec.

[0128] Furthermore, a molded article containing the polybutylene terephthalate resin composition of the present invention will be described. In describing the molded article containing the polybutylene terephthalate resin composition of the present invention, all the contents of the above-mentioned polybutylene terephthalate resin composition are included.

[0129] Molded product The polybutylene terephthalate resin composition of the present invention can be usefully used for molded articles that require moldability, mechanical properties, high load heat resistance, and a fast injection solidification rate through sufficient complementarity between components.

[0130] The method for manufacturing the molded article can be manufactured by a method commonly used in the industry. As an example, using a melt-kneaded product, pellets, or a sheet (plate material) molded therefrom of the polybutylene terephthalate resin composition according to the present invention as a raw material, injection molding (injection molding), injection compression molding, extrusion molding (sheet casting), press molding, pressure air molding, thermoforming, compression molding, calender molding, or rotational molding, etc. can be applied.

[0131] The polybutylene terephthalate resin composition described herein can, for example, be produced by using a twin-screw extruder (φ40, L / D: 42, equipped with SM Platek) set at 250 °C, under 250 rpm, feeding a base (polybutylene terephthalate) resin, a carboxy-reactive epoxy resin, a polybutadiene rubber, an injection solidification accelerator, and an additive into the main feed port at a supply rate of 50 kg / h, and performing melt-kneading and extrusion to produce pellets.

[0132] The polybutylene terephthalate resin composition described herein can, as another example, be produced by using a twin-screw extruder (φ40, L / D: 42, equipped with SM Platek) set at 280 °C, under 375 rpm, feeding a base (polybutylene terephthalate) resin and a carboxy-reactive epoxy resin into the main feed port, and feeding a polybutadiene rubber, an injection solidification accelerator, and an additive into the auxiliary feed port at a supply rate of 75 kg / h, and performing melt-kneading and extrusion to produce pellets.

[0133] As another example, the polybutylene terephthalate resin composition described herein can be used to produce pellets by using a twin-screw extruder (φ40, L / D: 42, equipped with SM Platek) set at 250°C, operating at 250 rpm, feeding the base (polybutylene terephthalate) resin, carboxy-reactive epoxy resin, and polybutadiene rubber into the main inlet, and supplying the injection solidification accelerator and additives into the auxiliary inlet at a supply rate of 50 kg / h for melt kneading and extrusion.

[0134] The pellets can be put into an injection molding machine to produce molded products.

[0135] In order to indirectly confirm the physical properties of the produced molded products, the pellets can be injected using an injection molding machine (ENGEL, 80 tons) at an injection temperature of 260°C, a mold temperature of 60°C, and an injection speed of 30 mm / sec to produce test pieces conforming to ISO standards.

[0136] Based on the measurement results of the produced test pieces, the polybutylene terephthalate resin composition of the present invention may have a melt flow index (250°C, 2.16 kgf) measured in accordance with ISO 1133 of, for example, 10 g / 10 min or more, and specifically, 10 to 30 g / 10 min.

[0137] The polybutylene terephthalate resin composition of the present invention may have a tensile strength measured in accordance with ISO 527 of, for example, 45 MPa or more, and specifically, 45 to 50 MPa.

[0138] The polybutylene terephthalate resin composition of the present invention may have an elongation at break measured in accordance with ISO 527 of, for example, 15% or more, and specifically, 20 to 85%.

[0139] The polybutylene terephthalate resin composition of the present invention may have an Izod impact strength (23°C, notch) measured in accordance with ISO 180 of, for example, 7 kJ / m 2 and specifically, 7.8 to 10 kJ / m 2 may also be acceptable.

[0140] The polybutylene terephthalate resin composition of the present invention may have a heat distortion temperature measured under a load of 0.45 MPa in accordance with ISO 75 of 100°C or higher, for example, and may be 100 to 130°C as a specific example.

[0141] The polybutylene terephthalate resin composition of the present invention may have a heat distortion temperature measured under a high load of 1.8 MPa in accordance with ISO 75 of 40°C or higher, for example, and may be 45 to 55°C as a specific example.

[0142] The polybutylene terephthalate resin composition of the present invention may have a flexural modulus measured in accordance with ISO 178 of 1700 MPa or higher, for example, and may be 1750 to 2100 MPa as a specific example.

[0143] The polybutylene terephthalate resin composition of the present invention may have a flexural strength measured in accordance with ISO 178 of 60 MPa or higher, for example, and may be 64 to 70 MPa as a specific example.

[0144] The polybutylene terephthalate resin composition of the present invention may have a curing rate (injection cooling time) measured in accordance with an internal evaluation method reduced to 14 seconds or less, for example, and may be reduced to 6 to 14 seconds, preferably about 6 to 12 seconds as a specific example.

[0145] The polybutylene terephthalate resin composition of the present invention may have a maximum peak pressure during injection of 1000 kgf / cm 2 or higher, and may be 1000 to 1150 kgf / cm 2 as a specific example.

[0146] For the polybutylene terephthalate resin composition of the present invention, when an iron rod is inserted into the lance part inside the fastening part and the lance is strongly pushed up and bounced using the lever principle and the presence or absence of damage is examined, it may be undamaged.

[0147] Specifically, the molded article may be a fastening part of a vehicle, but is not limited to a specific type.

[0148] That is, the polybutylene terephthalate resin composition according to one embodiment of the present invention is characterized by including a polybutylene terephthalate resin having a specific intrinsic viscosity, a polybutadiene rubber, and a carboxy-reactive epoxy resin. The molded product manufactured from the composition simultaneously improves the injection solidification rate and impact strength, which are in a trade-off relationship, by changing the material used from the conventional material, satisfies the physical property balance such as mechanical properties, fluidity, and heat resistance characteristics, and has the advantage of providing excellent product reliability and appearance quality.

[0149] In explaining the polybutylene terephthalate resin composition, its manufacturing method, and the molded product of the present invention, it is explicitly stated that other conditions, equipment, etc. that are not explicitly described can be appropriately selected within the range normally practiced in the industry and are not particularly limited.

[0150] Hereinafter, the embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement them. However, the present invention can be realized in various different forms and is not limited to the embodiments described herein.

[0151] [Examples] Example 1 and Comparative Examples 1 to 5 (experiments without injection curing accelerator) The raw materials used in the examples and comparative examples are as follows. A-1) Polybutylene terephthalate resin: intrinsic viscosity (IV) 0.83, product name TH6082A A-2) Polybutylene terephthalate resin: IV, 1.0 product name TH6098A A-3) Polybutylene terephthalate resin: IV 1.12, product name PBT1100-211S (B) Carboxy-reactive epoxy resin: ethylene / n-butyl acrylate / glycidyl methacrylate resin, product name PTW of Dupont (C) Polybutadiene rubber C-1) Polybutadiene rubber, product name EM538 of LG Chem C-2) Polybutadiene rubber, product name EM500 by LG Chem (D) Injection curing accelerator D-1) Ethylene acrylate acid-based compound: product name P250 by Bruggemann D-2) Inorganic injection curing accelerator: product name KCM6300 by Koch (Additive) (E) Lubricant: LC102N (F) Antioxidant F-1) Primary antioxidant: IR1010 F-2) Secondary antioxidant: Songnox6260 (G) Colorant: product name NR9089 Black by LG Chem (H) Polyethylene elastomer, product name 1055D by LG Chem

[0152] After mixing the raw materials of the polybutylene terephthalate resin composition described in Table 1 below, through extrusion, a polybutylene terephthalate resin composition with a uniform dispersion degree was produced in pellet form, and then heat was applied to the pellets and injected into a mold frame, and after cooling, a test piece that can be used as a molded product was produced through an injection process for producing parts.

[0153] Specifically, after mixing including each component shown in Table 1 below with a mixer, using a twin-screw extruder (φ40, L / D: 42, equipped with SM Platek) set at 250 °C, at 250 rpm, it was fed into the main inlet at a supply rate of 75 kg / h and extruded to produce polybutylene terephthalate resin composition pellets.

[0154] The produced pellets were dried in a convection oven at 80 °C for 4 hours or more, and then injected using an injection molding machine (ENGEL, 80 tons) at an injection temperature of 260 °C, a mold temperature of 60 °C, and an injection speed of 30 mm / sec to produce ISO test pieces.

[0155]

Table 1

[0156] (The raw materials used in Table 1 above are charged with the G component in parts by weight with respect to a total of 100 parts by weight of all of A-1 to F-2.)

[0157] Test Example 1: Evaluation of physical properties of molded product test pieces The physical properties of the molded product test pieces produced in Example 1 and Comparative Examples 1 to 5 were evaluated. The evaluation criteria are as follows. - Melt Index: Conducted in accordance with ISO 1133 (250 °C, 2.16 kg) - Tensile strength and elongation: Conducted in accordance with ISO 527 (50 mm / min) - Impact strength (IZOD): Conducted in accordance with ISO 180 / 1A (Notched, 23 °C) - Heat distortion temperature: Conducted in accordance with ISO 75 at high load of 1.82 MPa and low load of 0.45 MPa respectively - Flexural strength and flexural modulus: Conducted in accordance with ISO 178 (4 mm, SPAN64, speed 2 mm / min) - Curing speed (injection cooling time): The cooling time required until it was cured and there was no further change in length was measured in seconds. - Maximum peak pressure of injection: The maximum peak pressure applied to the injection machine at the time of curing was measured in kgf / cm 2 units. - Part lance crack: The part lance crack was measured by the method shown in Figure 1. The following Figure 1 is a diagram schematically showing the measurement method of the part lance crack. An iron rod was inserted into the lance part inside the connector test piece on the left side of Figure 1, and the lance was strongly pushed up by the principle of a lever and bounced up, and the presence or absence of damage was visually observed (see the right side figure of Figure 1). It was marked as NG when damaged and OK when not damaged.

[0158] The results measured according to the above evaluation criteria are as shown in Table 2 below.

[0159]

Table 2

[0160] Referring to Table 1 and Table 2 above, the polybutylene terephthalate resin composition of Example 1 according to the present invention has high impact strength, flexural modulus, heat distortion temperature under high load, and melt flow rate, and the solidification rate and the maximum peak pressure of injection are shortened, and no part lance crack occurs. Therefore, the molded product manufactured using this composition basically satisfies physical properties such as impact strength, tensile strength, and flexural strength, and also has excellent processability and heat resistance under high load. It can be confirmed that the reduction of the solidification rate reduces the degree of appearance defects, providing both product reliability and appearance quality.

[0161] On the contrary, Comparative Examples 1 to 5, in which the ratio of the intrinsic viscosity is used outside the appropriate formulation, showed a decrease in fluidity and a gradually slower solidification rate when compared with Example 1.

[0162] In particular, Comparative Example 3, which uses polybutylene terephthalate resin alone without the formulation of the ratio of the intrinsic viscosity, has a decrease in injection moldability due to a decrease in flow caused by high viscosity, and problems such as non-molding occur in a miniaturized / thinned mold. Comparative Example 4 showed a poor result of a decrease in impact strength and the occurrence of part cracks.

[0163] In addition, Comparative Example 5, which uses polybutadiene rubber outside the appropriate composition, showed a poor result of a decrease in rigidity and impact strength.

[0164] Furthermore, when an inorganic injection solidification accelerator was used, it was additionally confirmed that part cracks occurred due to a decrease in impact strength.

[0165] Examples 2 to 4 and Comparative Examples 6 to 14 After mixing the raw materials of the polybutylene terephthalate resin composition described in Table 3 and Table 4 below, through extrusion, a polybutylene terephthalate resin composition with a uniform dispersion degree was produced in pellet form. Then, heat was applied to the pellets and injected into a mold frame, and after cooling, through an injection process for producing parts, test pieces that can be used as molded products were produced. Unless otherwise specified, the extrusion and injection conditions used in Example 1 were applied identically.

[0166]

Table 3

[0167]

Table 4

[0168] (For reference, the raw materials used in Table 3 and Table 4 above, when combined from A-1 to H, have a total weight percentage of 100%.)

[0169] Test Example 2: Evaluation of physical properties of molded product test pieces The physical properties of the molded product test pieces produced in Examples 2 to 4 and Comparative Examples 6 to 14 were evaluated and measured, and the results are as shown in Table 5 and Table 6 below.

[0170]

Table 5

[0171]

Table 6

[0172] Referring to Table 3 to Table 6 above, the polybutylene terephthalate resin compositions of Examples 2 to 4 according to the present invention have high impact strength, flexural modulus, heat distortion temperature under high load, and melt flow index, and the solidification rate and the maximum injection peak pressure are shortened, and no part lance cracks occur. Therefore, the molded products produced using this resin composition basically satisfy the physical properties such as impact strength, tensile strength, and flexural strength, and are excellent in processability and high load heat resistance characteristics. By shortening the solidification rate, the degree of occurrence of appearance defects is reduced, and it can be confirmed that both product reliability and appearance quality are provided.

[0173] On the contrary, Comparative Examples 6 to 14, which use formulations outside the appropriate ratio of intrinsic viscosity, showed a decrease in fluidity, a gradual slowdown in the solidification rate, and a significant reduction in impact strength when compared with Examples 2 to 4.

[0174] That is, the polybutylene terephthalate resin composition according to one embodiment of the present invention contains a composite resin including a specific weight % of polybutylene terephthalate resin and polyethylene terephthalate resin, a specific weight % of a (meth)acrylate compound-conjugated diene compound-aromatic vinyl compound copolymer, a hydrolysis stabilizer in which a carboxy-reactive epoxy resin is mixed, and further an injection solidification accelerator. By including these components, the molded article produced from the composition simultaneously improves the injection solidification rate and impact strength that are in a trade-off relationship, satisfies the physical property balance such as mechanical properties, fluidity, and heat resistance characteristics, and has the advantage of providing excellent product reliability and appearance quality.

Claims

1. A base resin comprising 80 to 99% by weight of a polybutylene terephthalate resin having an intrinsic viscosity (η) exceeding 1.05 and a polybutylene terephthalate resin having an intrinsic viscosity (η) of 1.05 or less, 0.01 to 10% by weight of a carboxy-reactive epoxy resin, and 0.01 to 5% by weight of a polybutadiene rubber, which is a polybutylene terephthalate resin composition, The polybutylene terephthalate resin having an intrinsic viscosity (η) of 1.05 or less contains 0 to 68% by weight of a polybutylene terephthalate resin having an intrinsic viscosity exceeding 0.9 and 1.05 or less, and 0 to 50% by weight of a polybutylene terephthalate resin having an intrinsic viscosity of 0.7 or more and less than 0.9, The polybutylene terephthalate resin having an intrinsic viscosity (η) of 1.05 or less contains a polybutylene terephthalate resin having an intrinsic viscosity of less than 0.9 and a polybutylene terephthalate resin having an intrinsic viscosity exceeding 0.9 and 1.05 or less in a weight ratio of 30:70 to 60:40, The polybutadiene rubber has a bulk density measured in accordance with ASTM D1895 of 0.25 g / cc or more, an Izod impact strength (-30°C, 1 / 4'' thickness) measured in accordance with ASTM D256 of 10 kg / cm.cm or more, and an Izod impact strength (23°C, 1 / 4'' thickness) of 50 kg / cm.cm or more, and the fraction passing through #20 mesh in all particles is 3% or less in 100% of the total number of all particles, The carboxy-reactive epoxy resin contains one or more selected from an ethylene-n-butyl acrylate-glycidyl methacrylate copolymer, an ethylene-glycidyl methacrylate copolymer, an ethylene-acrylic acid ester-glycidyl methacrylate copolymer, an ethylene-methyl acrylate-glycidyl methacrylate copolymer, an ethylene-dimethacrylate-glycidyl methacrylate copolymer, an ethylene-acrylate-glycidyl methacrylate copolymer, and an ethylene-vinyl acetate-glycidyl methacrylate copolymer, The polybutylene terephthalate resin composition does not contain polyethylene terephthalate resin. Polybutylene terephthalate resin composition.

2. The polybutylene terephthalate resin having an intrinsic viscosity (η) of more than 1.05 contains, based on 100% by weight in total of the base resin, carboxy-reactive epoxy resin, polybutadiene rubber, additive and optional injection solidification accelerator constituting the polybutylene terephthalate resin composition, 29 to 55% by weight of a polybutylene terephthalate resin having an intrinsic viscosity of more than 1.05 and 1.5 or less. The polybutylene terephthalate resin composition according to claim 1.

3. The carboxy-reactive epoxy resin contains 1 to 15% by weight of units derived from glycidyl methacrylate. The polybutylene terephthalate resin composition according to claim 1.

4. The polybutylene terephthalate resin composition contains 1% by weight or less of one or more injection solidification accelerators selected from talc, wollastonite and ethylene acrylate-based compounds. The polybutylene terephthalate resin composition according to claim 1.

5. The ethylene acrylate-based compound is contained in an amount of 0.01 to 1% by weight based on 100% by weight in total of the base resin, carboxy-reactive epoxy resin, polybutadiene rubber, additive and injection solidification accelerator constituting the polybutylene terephthalate resin composition. The polybutylene terephthalate resin composition according to claim 4.

6. The polybutylene terephthalate resin composition contains an additive selected from a lubricant, an antioxidant and a colorant. The polybutylene terephthalate resin composition according to claim 1.

7. 29 to 55% by weight of a polybutylene terephthalate resin having an intrinsic viscosity (η) of more than 1.05 and 1.5 or less, 0 to 68% by weight of a polybutylene terephthalate resin having an intrinsic viscosity (η) of more than 0.9 and 1.05 or less, 0 to 50% by weight of a polybutylene terephthalate resin having an inherent viscosity (η) of 0.7 or more and less than 0.9, 0.01 to 10% by weight of a carboxy-reactive epoxy resin, 0.01 to 5% by weight of a polybutadiene rubber, A polybutylene terephthalate resin composition containing 0 to 1% by weight of an injection curing accelerator, The polybutylene terephthalate resin having an inherent viscosity (η) of 1.05 or less contains a polybutylene terephthalate resin having an inherent viscosity of less than 0.9 and a polybutylene terephthalate resin having an inherent viscosity of more than 0.9 and 1.05 or less in a weight ratio of 30:70 to 60:40, The polybutadiene rubber has a bulk density measured in accordance with ASTM D1895 of 0.25 g / cc or more, an Izod impact strength (-30 °C, 1 / 4'' thickness) measured in accordance with ASTM D256 of 10 kg / cm.cm or more, an Izod impact strength (23 °C, 1 / 4'' thickness) of 50 kg / cm.cm or more, and the fraction passing through a #20 mesh in all particles is 3% or less in the total number of all particles, The carboxy-reactive epoxy resin contains one or more selected from an ethylene-n-butyl acrylate-glycidyl methacrylate copolymer, an ethylene-glycidyl methacrylate copolymer, an ethylene-acrylic acid ester-glycidyl methacrylate copolymer, an ethylene-methyl acrylate-glycidyl methacrylate copolymer, an ethylene-dimethacrylate-glycidyl methacrylate copolymer, an ethylene-acrylate-glycidyl methacrylate copolymer, and an ethylene-vinyl acetate-glycidyl methacrylate copolymer, The polybutylene terephthalate resin composition does not contain a polyethylene terephthalate resin, Polybutylene terephthalate resin composition.

8. i) 29 to 54% by weight of a polybutylene terephthalate resin having an inherent viscosity (η) of more than 1.05 and 1.5 or less, ii) 35 to 68% by weight of a polybutylene terephthalate resin having an inherent viscosity (η) of more than 0.9 and not more than 1.05, or 41 to 49% by weight of a polybutylene terephthalate resin having an inherent viscosity (η) of 0.7 or more and less than 0.9, and iii) 0.01 to 10% by weight of a carboxy-reactive epoxy resin, and iv) 0.01 to 5% by weight of a polybutadiene rubber, and v) 0 to 1% by weight of an injection curing accelerator, and A polybutylene terephthalate resin composition in which the total weight of the polybutylene terephthalate resins of i) and ii) is 80 to 99% by weight, The polybutylene terephthalate resin having an inherent viscosity (η) of not more than 1.05 contains a polybutylene terephthalate resin having an inherent viscosity of less than 0.9 and a polybutylene terephthalate resin having an inherent viscosity of more than 0.9 and not more than 1.05 in a weight ratio of 30:70 to 60:40, The polybutadiene rubber has a bulk density of 0.25 g / cc or more measured in accordance with ASTM D1895, an Izod impact strength (-30 °C, 1 / 4'' thickness) of 10 kg / cm.cm or more measured in accordance with ASTM D256, an Izod impact strength (23 °C, 1 / 4'' thickness) of 50 kg / cm.cm or more, and the fraction passing through a #20 mesh in all particles is 3% or less in 100% of the total number of all particles, The carboxy-reactive epoxy resin contains one or more selected from ethylene-n-butyl acrylate-glycidyl methacrylate copolymer, ethylene-glycidyl methacrylate copolymer, ethylene-acrylic ester-glycidyl methacrylate copolymer, ethylene-methyl acrylate-glycidyl methacrylate copolymer, ethylene-dimethacrylate-glycidyl methacrylate copolymer, ethylene-acrylate-glycidyl methacrylate copolymer, and ethylene-vinyl acetate-glycidyl methacrylate copolymer, The polybutylene terephthalate resin composition does not contain a polyethylene terephthalate resin, Polybutylene terephthalate resin composition.

9. A method for producing a polybutylene terephthalate resin composition, comprising the steps of melt-kneading and extruding 80 to 99% by weight of a base resin containing a polybutylene terephthalate resin having an intrinsic viscosity (η) exceeding 1.05 and a polybutylene terephthalate resin having an intrinsic viscosity (η) of 1.05 or less, 0.01 to 10% by weight of a carboxy-reactive epoxy resin, 0.01 to 5% by weight of a polybutadiene rubber, and 0 to 1% by weight of an injection curing accelerator using an extruder, The polybutylene terephthalate resin having an intrinsic viscosity (η) exceeding 1.05 contains 29 to 55% by weight of a polybutylene terephthalate resin having an intrinsic viscosity (η) exceeding 1.05 and not exceeding 1.5 with respect to 100% by weight of the total amount of the base resin, the carboxy-reactive epoxy resin, the polybutadiene rubber, additives and injection curing accelerator constituting the polybutylene terephthalate resin composition, The polybutylene terephthalate resin having an intrinsic viscosity (η) of 1.05 or less contains a polybutylene terephthalate resin having an intrinsic viscosity of less than 0.9 and a polybutylene terephthalate resin having an intrinsic viscosity exceeding 0.9 and not exceeding 1.05 in a weight ratio of 30:70 to 60:40, The polybutadiene rubber has a bulk density measured in accordance with ASTM D1895 of 0.25 g / cc or more, an Izod impact strength (-30 °C, 1 / 4'' thickness) measured in accordance with ASTM D256 of 10 kg / cm.cm or more, and an Izod impact strength (23 °C, 1 / 4'' thickness) of 50 kg / cm.cm or more, and the fraction passing through #20 mesh in all particles is 3% or less in 100% of the total number of all particles, The carboxy-reactive epoxy resin contains one or more selected from ethylene-n-butyl acrylate-glycidyl methacrylate copolymer, ethylene-glycidyl methacrylate copolymer, ethylene-acrylic acid ester-glycidyl methacrylate copolymer, ethylene-methyl acrylate-glycidyl methacrylate copolymer, ethylene-dimethacrylate-glycidyl methacrylate copolymer, ethylene-acrylate-glycidyl methacrylate copolymer, and ethylene-vinyl acetate-glycidyl methacrylate copolymer. The polybutylene terephthalate resin composition does not contain polyethylene terephthalate resin. A method for producing a polybutylene terephthalate resin composition.

10. A molded article comprising the polybutylene terephthalate resin composition according to any one of Claims 1 to 8.

11. The molded article according to Claim 10, wherein the molded article is a fastening part for automobile electrical equipment.

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