Inorganic reinforced thermoplastic polyester resin composition and method for producing the same

Abstract

The present invention provides an inorganic reinforced thermoplastic polyester resin composition capable of producing long, thin-walled molded articles having excellent appearance while maintaining inherent mechanical properties such as rigidity and impact resistance. The composition comprises 20 to 55 parts by mass of a polybutylene terephthalate resin (A), 1 to 30 parts by mass of a polyethylene terephthalate resin (B), 3 to 30 parts by mass of a semi-crystalline resin and / or a non-crystalline resin (C), and 25 to 65 parts by mass of an inorganic reinforcing material (D). The inorganic reinforcing material (D) in the resin composition has a number average fiber length Ln of 100 to 500 μm. The inorganic reinforced thermoplastic polyester resin composition has excellent fluidity and a cooling crystallization temperature within a specific range.

Description

Technical Field

[0001] The present invention relates to an inorganic reinforced thermoplastic polyester resin composition, which contains a thermoplastic polyester resin and inorganic reinforcing materials such as glass reinforcing fibers. Background Art

[0002] Polyester resins are generally known to have excellent mechanical properties, heat resistance, and chemical resistance, and are widely used in automotive parts, electrical and electronic components, and household goods. Among them, polyester resin compositions reinforced with inorganic reinforcing materials such as glass fiber are known to exhibit significantly improved rigidity, strength, and heat resistance. In particular, rigidity increases in proportion to the amount of inorganic reinforcing material added.

[0003] However, increasing the amount of inorganic reinforcing materials such as glass fiber can cause them to float on the surface of the molded part, reducing the appearance, particularly the surface gloss, and significantly diminishing the product's value. For example, air conditioner fans, which are particularly demanding of mechanical properties and aesthetics among automotive parts, are becoming increasingly elongated and thinner from a design perspective, requiring them to possess higher strength and rigidity without the aesthetic appeal of floating glass fiber.

[0004] Patent Document 1 discloses a resin composition that suppresses glass fiber floating even in a high-rigidity material containing 50% by mass or more of glass fiber by controlling the curing (crystallization) rate of the resin composition within a mold. However, this approach is effective only in shapes that flow relatively easily. In long, thin-walled molded articles, such as those with a thickness of less than 2 mm and a length exceeding 200 mm, the glass fiber floating in the composition of this invention becomes noticeable, preventing the achievement of a good appearance.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 5396690 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] To improve the fluidity of the resin composition, the molecular weight of the resin component is reduced to lower the viscosity, and the amount of reinforcing material is reduced to achieve high fluidity. However, because the mechanical strength is reduced at the same time, the fluidity and mechanical strength are in a trade-off.

[0010] The present invention aims to obtain a long, thin-walled molded article of an inorganic reinforced thermoplastic polyester resin composition containing a thermoplastic polyester resin and an inorganic reinforcing material such as glass reinforcing fiber, while maintaining inherent mechanical properties such as rigidity and impact resistance, and also obtaining a molded article having excellent appearance.

[0011] Technical means to solve the problem

[0012] The present inventors conducted intensive research to address the above-mentioned issues and discovered that, in a resin composition containing a relatively high amount of inorganic reinforcing materials such as glass reinforcing fibers, if the fiber length of the inorganic reinforcing materials is within a predetermined range, mechanical strength can be maintained even with shorter fiber lengths, and fluidity can be improved, thereby completing the present invention.

[0013] That is, the present invention is as follows.

[0014] [1] An inorganic reinforced thermoplastic polyester resin composition, characterized in that it contains: 20 to 55 parts by mass of a polybutylene terephthalate resin (A), 1 to 30 parts by mass of a polyethylene terephthalate resin (B), 3 to 30 parts by mass of a semi-crystalline resin and / or a non-crystalline resin (C), and 25 to 65 parts by mass of an inorganic reinforcing material (D);

[0015] The inorganic reinforced thermoplastic polyester resin composition has an average fiber length Ln of 100 to 500 μm.

[0016] The flow length of the inorganic reinforced thermoplastic polyester resin composition is 80 mm or more,

[0017] The inorganic reinforced thermoplastic polyester resin composition has a cooling crystallization temperature (Tc2M) determined using a differential scanning calorimeter (DSC) in the range of 160°C ≤ Tc2M ≤ 185°C.

[0018] [2] The inorganic reinforced thermoplastic polyester resin composition according to [1] is characterized in that the semi-crystalline resin and / or non-crystalline resin (C) is selected from at least one of a terephthalic acid / / ethylene glycol / neopentyl glycol copolymer, a terephthalic acid / / ethylene glycol / 1,2-propylene glycol copolymer, and a terephthalic acid / isophthalic acid / / ethylene glycol / neopentyl glycol copolymer.

[0019] [3] The inorganic reinforced thermoplastic polyester resin composition according to [1] or [2], characterized in that, when the cooling crystallization temperature Tc2N (°C) is determined using a differential scanning calorimeter (DSC) for the polyester resin composition that does not contain the semi-crystalline resin and / or the non-crystalline resin (C), the following relationship is satisfied:

[0020] Tc2N-Tc2M≥10℃

[0021] [4] The inorganic reinforced thermoplastic polyester resin composition according to any one of [1] to [3], characterized in that the weight average molecular weight Mw and number average molecular weight Mn of the resin component of the inorganic reinforced thermoplastic polyester resin composition satisfy Mw / Mn≤5.

[0022] [5] The inorganic reinforced thermoplastic polyester resin composition according to any one of [1] to [4], characterized in that the content of the inorganic reinforcing material (D) in the inorganic reinforced thermoplastic polyester resin composition is 40 to 60% by mass.

[0023] [6] The inorganic reinforced thermoplastic polyester resin composition according to any one of [1] to [5], characterized in that the number average fiber length Ln and the weight average fiber length Lw of the inorganic reinforcing material (D) in the inorganic reinforced thermoplastic polyester resin composition satisfy Lw / Ln≤2.0.

[0024] [7] A method for producing an inorganic reinforced thermoplastic polyester resin composition according to any one of [1] to [6], characterized in that a twin-screw extruder equipped with a plurality of side feeders is used, and the same inorganic reinforcing material is fed separately from the plurality of side feeders.

[0025] Effects of the Invention

[0026] According to the present invention, a long, thin-walled molded article of an inorganic reinforced thermoplastic polyester resin composition can be obtained while maintaining inherent mechanical properties such as rigidity and impact resistance and having excellent appearance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] [ Figure 1 ] Schematically showing an example of a molded product formed for evaluating warpage deformation (a) a schematic top view and (b) a schematic side view.

[0028] Explanation of symbols

[0029] L: Flow direction of resin composition

[0030] W: Direction perpendicular to the flow of the resin composition

[0031] 1: Molded products

[0032] 2: Film gate

[0033] 3: Ribs

[0034] A: Warping deformation DETAILED DESCRIPTION

[0035] Hereinafter, embodiments of the present invention will be described.

[0036] In the present invention, the polybutylene terephthalate resin (A) is the main component containing the largest amount of the total polyester resin in the resin composition of the present invention. While the polybutylene terephthalate resin (A) is not particularly limited, a homopolymer composed of terephthalic acid and 1,4-butanediol is primarily used. Furthermore, other components may be copolymerized in an amount up to approximately 5 mol% relative to 100 mol% of the total dicarboxylic acid component (or 100 mol% of the total glycol component) within a range that does not impair moldability, crystallinity, or surface gloss.

[0037] For example, the reduced viscosity (measured at 30°C using an Ubbelohde viscometer after dissolving 0.1 g of a sample in 25 mL of a mixed solvent of phenol / tetrachloroethane (6 / 4 by mass)) is preferably in the range of 0.4 to 1.2 dL / g, and more preferably in the range of 0.5 to 0.8 dL / g. A reduced viscosity below 0.4 dL / g tends to reduce toughness, while a reduced viscosity exceeding 1.2 dL / g reduces flowability, potentially preventing the desired good appearance of the molded product.

[0038] The content (blended amount) of each component in the inorganic reinforced thermoplastic polyester resin composition of the present invention is expressed as the content (parts by mass) when the total of the polybutylene terephthalate resin (A), the polyethylene terephthalate resin (B), the semi-crystalline resin and / or the amorphous resin (C), and the inorganic reinforcing material (D) is 100 parts by mass.

[0039] The content of the polybutylene terephthalate resin (A) is 20 to 55 parts by mass, preferably 20 to 50 parts by mass, and more preferably 22 to 45 parts by mass.

[0040] The polyethylene terephthalate resin (B) in the present invention refers to polyethylene terephthalate resin (PET), a typical thermoplastic polyester resin obtained by polycondensation of terephthalic acid and ethylene glycol. The reduced viscosity of PET (measured at 30°C using an Ubbelohde viscometer after dissolving 0.1 g of a sample in 25 mL of a mixed solvent of phenol / tetrachloroethane (6 / 4 by mass)) is preferably in the range of 0.4 to 1.0 dL / g, and more preferably in the range of 0.5 to 0.9 dL / g. A reduced viscosity below 0.4 dL / g tends to reduce toughness, while a viscosity exceeding 1.0 dL / g reduces flowability, potentially preventing the desired good appearance of the molded product.

[0041] The content of the polyethylene terephthalate resin (B) is 1 to 30 parts by mass, preferably 1 to 25 parts by mass, and more preferably 3 to 20 parts by mass.

[0042] The semi-crystalline resin and / or amorphous resin (C) in the inorganic reinforced thermoplastic polyester resin composition of the present invention is not particularly limited, as long as it is compatible with the polybutylene terephthalate resin (A) and the polyethylene terephthalate resin (B) and can delay crystallization. Examples include copolyesters such as copolymerized polybutylene terephthalate and copolymerized polyethylene terephthalate, and amorphous resins such as polycarbonate resins. Furthermore, two or more resins may be used.

[0043] The content of the semi-crystalline and / or amorphous resin (C) in the inorganic reinforced thermoplastic polyester resin composition of the present invention is 3 to 30 parts by mass, preferably 3 to 25 parts by mass, and more preferably 8 to 15 parts by mass. If the content is less than 3 parts by mass, poor appearance due to floating fibers such as glass fibers becomes noticeable. If the content exceeds 30 parts by mass, while the appearance of the molded article improves, the molding cycle is prolonged, which is not ideal. When two or more semi-crystalline and / or amorphous resins (C) are used, the content indicated is the total amount.

[0044] For example, a copolymerized polybutylene terephthalate is a resin containing 80 mol% or more of 1,4-butanediol, with the total acid content and the total glycol content accounting for 100 mol%, and the total of terephthalic acid and 1,4-butanediol accounting for 120 to 180 mol%. The copolymerized polybutylene terephthalate may contain at least one member selected from the group consisting of isophthalic acid, sebacic acid, adipic acid, trimellitic acid, 2,6-naphthalene dicarboxylic acid, ethylene glycol, diethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, 1,2-propylene glycol, 1,3-propylene glycol, and 2-methyl-1,3-propanediol. Of these, isophthalic acid is preferred as the copolymerized component. The copolymerization ratio of the copolymerized polybutylene terephthalate is preferably 20 to 80 mol%, and more preferably 20 to 60 mol%, based on 100 mol% of the total acid content. If the copolymerization ratio is less than 20 mol%, mold transferability deteriorates and a satisfactory appearance tends to be difficult to obtain. If the copolymerization ratio exceeds 80 mol%, molding cycle efficiency decreases, leading to a decrease in mold releasability.

[0045] As a measure of the molecular weight of copolymerized polybutylene terephthalate, while varying slightly depending on the specific copolymer composition, the reduced viscosity (measured at 30°C using an Ubbelohde viscometer after dissolving 0.1 g of a sample in 25 mL of a mixed solvent of phenol and tetrachloroethane (6 / 4 by mass)) is preferably 0.4 to 1.5 dL / g, and more preferably 0.4 to 1.3 dL / g. A reduced viscosity below 0.4 dL / g tends to reduce toughness, while a reduced viscosity exceeding 1.5 dL / g reduces fluidity.

[0046] Furthermore, as a copolymerized polyethylene terephthalate, for example, a resin containing 40 mol% or more of ethylene glycol, with the total acid component and the total glycol component being 100 mol%, and the total of terephthalic acid and ethylene glycol accounting for 80 to 180 mol%. The copolymerization component may contain at least one member selected from the group consisting of isophthalic acid, sebacic acid, adipic acid, trimellitic acid, 2,6-naphthalene dicarboxylic acid, diethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, 1,4-butanediol, 1,2-propylene glycol, 1,3-propylene glycol, and 2-methyl-1,3-propanediol, preferably amorphous. Among these, neopentyl glycol or a combination of neopentyl glycol and isophthalic acid is preferred as a copolymerization component from the perspective of various properties. As a copolymerization component, 1,4-butanediol is preferably used at 20 mol% or less.

[0047] When the total glycol components constituting the copolymerized polyethylene terephthalate are taken as 100 mol %, the copolymerization ratio of the neopentyl glycol is preferably 20 to 60 mol %, more preferably 25 to 50 mol %.

[0048] When the total acid components constituting the copolymerized polyethylene terephthalate are taken as 100 mol %, the copolymerization ratio of isophthalic acid is preferably 20 to 60 mol %, more preferably 25 to 50 mol %.

[0049] As a measure of the molecular weight of copolymerized polyethylene terephthalate, while varying slightly depending on the specific copolymer composition, the reduced viscosity (measured at 30°C using an Ubbelohde viscometer after dissolving 0.1 g of a sample in 25 mL of a mixed solvent of phenol / tetrachloroethane (6 / 4 by mass)) is preferably 0.4 to 1.5 dL / g, and more preferably 0.4 to 1.3 dL / g. A reduced viscosity below 0.4 dL / g tends to reduce toughness, while a reduced viscosity exceeding 1.5 dL / g reduces fluidity.

[0050] The semi-crystalline resin and / or amorphous resin (C) is preferably at least one selected from a terephthalic acid / ethylene glycol / neopentyl glycol copolymer, a terephthalic acid / ethylene glycol / 1,2-propylene glycol copolymer, and a terephthalic acid / isophthalic acid / ethylene glycol / neopentyl glycol copolymer. Here, " / / " between the components distinguishes between the acid component and the diol component, and " / " distinguishes between the components within the acid component and the diol component.

[0051] When a polycarbonate resin is used in the present invention, a polycarbonate resin with high fluidity is particularly preferred. A melt volume flow rate (unit: cm2) measured at 300°C and a load of 1.2 kg is preferably used. 3The melt volume flow rate (MVR) of polycarbonate resins is preferably 20 to 100, more preferably 25 to 95, and even more preferably 30 to 90. Using a polycarbonate resin with a MVR below 20 can significantly reduce fluidity, resulting in reduced strand stability and poor moldability. A MVR exceeding 100 can easily lead to problems such as reduced physical properties due to excessively low molecular weight and gas generation due to decomposition.

[0052] The inorganic reinforcing material (D) in the present invention can include: plate-like crystals of talc, mica, unfired clay, amorphous or spherical calcium carbonate, fired clay, silica, glass beads, commonly used wollastonite and needle-shaped wollastonite, glass fiber, carbon fiber, aluminum borate, calcium titanate and other whiskers, milled fiber as a glass short fiber with an average fiber diameter of about 4 to 20 μm and a cut length of about 35 to 300 μm, etc., but is not limited to the above. In terms of the appearance of the molded product, talc or wollastonite is most preferred, and in terms of improving strength and rigidity, glass fiber is most preferred. These inorganic reinforcing materials can also be used alone or in combination of two or more. In the present invention, glass fiber is particularly preferred.

[0053] When glass fiber is used as the inorganic reinforcing material (D) of the present invention, for example, filament-shaped fibers obtained by melt-spinning glasses such as E glass (alkali-free glass), C glass (medium alkali glass, chemical glass), A glass (high alkali glass, Alkaliglass), S glass (high strength glass, high strength glass), and alkali-resistant glass can be mentioned. The average fiber diameter is about 4 to 50 μm and the cut length is about 3 to 6 mm, and extremely general fibers can be used. As the cross-sectional shape of the glass fiber, glass fibers with circular cross-sections and non-circular cross-sections can be used. As glass fibers with non-circular cross-sections, the cross-section perpendicular to the longitudinal direction of the fiber also includes nearly elliptical, nearly oblong, and nearly cocoon-shaped shapes, and the flatness is preferably 1.3 to 8. The flatness here refers to the ratio of the major diameter to the minor diameter when assuming a rectangle with the minimum area circumscribed to the cross-section perpendicular to the longitudinal direction of the glass fiber, with the length of the long side of the rectangle as the major diameter and the length of the short side as the minor diameter. The thickness of the glass fibers is not particularly limited, but those with a minor diameter of about 1 to 20 μm and a major diameter of about 2 to 100 μm can be used. These glass fibers may be used alone or in combination of two or more.

[0054] Glass fibers pre-treated with a silane coupling agent, such as an organosilane compound, an organotitanium compound, an organoborane compound, or an epoxy compound, are preferred. Inorganic reinforced thermoplastic polyester resin compositions containing glass fibers treated with a silane coupling agent are preferred because they yield molded articles with excellent mechanical and aesthetic properties. Furthermore, other inorganic reinforcing materials can be post-treated with a silane coupling agent.

[0055] In the inorganic reinforced thermoplastic polyester resin composition of the present invention, the content of the inorganic reinforcing material (D) is 25 to 65 parts by mass. The lower limit of the content of the inorganic reinforcing material (D) is preferably 30 parts by mass, more preferably 33 parts by mass, even more preferably 35 parts by mass, and particularly preferably 40 parts by mass. The upper limit of the content of the inorganic reinforcing material (D) is preferably 60 parts by mass, more preferably 57 parts by mass, and even more preferably 55 parts by mass.

[0056] Furthermore, the content of the inorganic reinforcing material (D) in the inorganic reinforced thermoplastic polyester resin composition is preferably 40 to 60 parts by mass.

[0057] The inorganic reinforced thermoplastic polyester resin composition of the present invention may contain an ester exchange inhibitor, depending on the intended purpose and within a range that does not impair the properties. As the name suggests, an ester exchange inhibitor is a stabilizer that prevents the ester exchange reaction of polyester resins. Regardless of the degree of optimization of manufacturing conditions, ester exchange often occurs in the case of alloys between polyester resins due to the application of thermal history. When this frequency becomes excessive, the expected properties of the alloy cannot be achieved. In particular, frequent ester exchange between polybutylene terephthalate and polycarbonate significantly reduces the crystallinity of the polybutylene terephthalate, making this undesirable.

[0058] As the transesterification inhibitor, a phosphorus compound having a catalyst deactivating effect on polyester resins can be preferably used, and for example, "ADK STAB AX-71" manufactured by ADEKA Corporation can be used.

[0059] The content of the transesterification inhibitor used in the present invention is preferably 0.05 to 2 parts by mass, more preferably 0.1 to 1 part by mass. If it is less than 0.05 parts by mass, the desired transesterification inhibitory performance may not be achieved. Conversely, if it exceeds 2 parts by mass, no improvement in the effect is observed and it may even cause an increase in gas.

[0060] The inorganic reinforced thermoplastic polyester resin composition of the present invention is characterized in that its cooling crystallization temperature, Tc2M, as determined using a differential scanning calorimeter (DSC), is 160°C or higher and lower than 185°C. Tc2M refers to the peak temperature of the crystallization peak in a thermogram obtained by heating the composition to 300°C at a heating rate of 20°C / min under a nitrogen flow, maintaining the temperature at that temperature for 5 minutes, and then cooling the composition to 100°C at a rate of 10°C / min. If Tc2M is above 185°C, the polyester resin composition crystallizes at a faster rate, causing premature crystallization within the mold. This, particularly in compositions containing a high amount of inorganic reinforcing material (D), tends to reduce the rate of injection pressure transmission. Furthermore, due to insufficient adhesion between the molded article and the mold and the effects of crystallization shrinkage, inorganic reinforcing materials such as glass fibers protrude from the surface of the molded article, resulting in a phenomenon known as glass fiber floating, which deteriorates the appearance of the molded article. In this case, a method of delaying the solidification of the molded product by raising the mold temperature to 120-130°C could be considered. However, while this method improves surface gloss and appearance in the center of the mold, where injection pressure is high, it increases the risk of defects such as glass flotation in the end areas, where injection pressure is less likely to increase, making it difficult to achieve a uniform, good appearance. Furthermore, the elevated temperature of the molded product after removal from the mold can lead to increased warpage.

[0061] On the other hand, when Tc2M is lower than 160°C, the crystallization rate becomes too slow. Due to the slow crystallization, there is a risk of poor demolding due to adhesion to the mold, resulting in deformation during ejection. In addition, since the pressure resin during molding can easily penetrate deeper into the emboss, the depth of the emboss tends to become uneven due to emboss misalignment during shrinkage or demolding of the resin in the mold, making it difficult to obtain a good emboss appearance. In addition, if the cooling time is extended to achieve sufficient crystallization, the molding cycle time will be longer, and productivity will decrease. In view of these concerns during molding, the inorganic reinforced thermoplastic polyester resin composition of the present invention is adjusted to obtain the optimal Tc2, and good appearance and moldability can be obtained even at a mold temperature below 100°C.

[0062] Therefore, when the inorganic reinforced thermoplastic polyester resin composition of the present invention is molded at a mold temperature of approximately 90°C, a good surface appearance can be obtained under a wide range of injection speeds and molding conditions. In particular, for molds subjected to texturing, a sufficiently dark appearance can be achieved, and a molded product with a uniform appearance and no uneven texturing can be obtained.

[0063] The inorganic reinforced thermoplastic polyester resin composition of the present invention has a cooling crystallization temperature Tc2M (°C) obtained by differential scanning calorimetry (DSC). In the inorganic reinforced thermoplastic polyester resin composition, the polyester resin composition containing only the semi-crystalline resin and / or the amorphous resin (C) has a cooling crystallization temperature Tc2N (°C) obtained by differential scanning calorimetry (DSC), preferably satisfying the following relationship:

[0064] Tc2N-Tc2M≥10℃

[0065] Tc2N-Tc2M is preferably 13° C. or higher, more preferably 15° C. or higher, further preferably 18° C. or higher, and particularly preferably 21° C. or higher. The upper limit is not particularly limited, but is approximately 30° C. in the present invention.

[0066] In inorganically reinforced thermoplastic polyester resin compositions, the key factors affecting the Tc2M (°C) temperature are the resin (B) and the resin (C). Resin (C) is particularly important because it has molecular compatibility with both resin (B) and resin (A), with similar molecular dispersions, and can impart a wide range of physical properties, from amorphous to crystalline, depending on the resin composition. Therefore, by adding an optimal amount of resin (C), the Tc2M of the inorganically reinforced thermoplastic polyester resin composition can be controlled, resulting in a good appearance for the molded product. Furthermore, it is possible to reduce warpage in the molded product. Resin (C) is extremely important for both good appearance and low warpage.

[0067] The number average fiber length Ln of the inorganic reinforcing material (D) in the inorganic reinforced thermoplastic polyester resin composition of the present invention is 100 to 500 μm, preferably 120 to 480 μm, more preferably 150 to 480 μm, and even more preferably 180 to 470 μm. When the number average fiber length Ln is within the above range, mechanical strength is not affected to a certain extent by fiber length, and a molded product having an excellent balance between mechanical properties and fluidity can be obtained. On the other hand, if Ln is less than 100 μm, mechanical strength decreases. If Ln exceeds 500 μm, fluidity decreases, and the anisotropy of shrinkage during molding becomes significant, resulting in increased warpage of the molded product.

[0068] Furthermore, the number average fiber length Ln and weight average fiber length Lw of the inorganic reinforcing material (D) in the inorganic reinforced thermoplastic polyester resin composition of the present invention preferably satisfy Lw / Ln ≤ 2.0. More preferably, it is 1.8 or less, and even more preferably, 1.5 or less. While the lower limit of Lw / Ln is not particularly limited, it is theoretically 1.0 or greater. When Lw / Ln exceeds 2.0, mechanical properties, appearance, and low warpage properties tend to be slightly reduced.

[0069] Furthermore, the inorganic reinforcing material (D) in the inorganic reinforced thermoplastic polyester resin composition of the present invention preferably has a single peak in the histogram of fiber length. If there are two peaks, the uniform dispersion of the inorganic reinforcing material in the resin decreases, and not only mechanical properties deteriorate, but warpage tends to increase.

[0070] Furthermore, the inorganic reinforced thermoplastic polyester resin composition of the present invention has a flow length of 80 mm or greater, preferably 90 mm or greater, more preferably 100 mm or greater, further preferably 110 mm or greater, and even more preferably 120 mm or greater. The flow length is measured using the method described in the following Examples (1 mm flow length). When the flow length is within the above range, the mold can be filled well even when molding without increasing the molding temperature, and defective products such as sink marks and short shots will not occur. Furthermore, since it is not necessary to increase the molding temperature, the cooling time after molding can be shortened, the molding cycle can be shortened, and molded products can be produced inexpensively. On the other hand, if the flow length is less than 80 mm, the fluidity of the resin composition decreases, the flow rate in the mold slows, and the resin material becomes difficult to fill throughout the mold. As a result, short shots and sink marks may occur in the molded product. The upper limit of the flow length of the inorganic reinforced thermoplastic polyester resin composition of the present invention is not particularly limited, but may be approximately 500 mm.

[0071] The inorganic reinforced thermoplastic polyester resin composition of the present invention may contain various known additives as needed, within a range that does not impair the characteristics of the present invention. Examples of known additives include colorants such as pigments, mold release agents, heat stabilizers, antioxidants, UV absorbers, light stabilizers, plasticizers, modifiers, antistatic agents, flame retardants, and dyes. These various additives may be present in a total amount of up to 5% by mass based on 100% by mass of the inorganic reinforced thermoplastic polyester resin composition. In summary, the total amount of (A), (B), (C), and (D) is preferably 95-100% by mass of 100% by mass of the inorganic reinforced thermoplastic polyester resin composition.

[0072] Examples of release agents include long-chain fatty acids or their esters or metal salts, amide compounds, polyethylene wax, silicone, and polyethylene oxide. Long-chain fatty acids with 12 or more carbon atoms are particularly preferred, such as stearic acid, 12-hydroxystearic acid, behenic acid, and montanic acid. Some or all of the carboxylic acids can be esterified with monoglycol or polyglycol, or they can be converted into metal salts. Amide compounds include ethylene bisterephthalamide and methylene bisstearamide. These release agents can be used individually or as a mixture.

[0073] As a method for producing the inorganic reinforced thermoplastic polyester resin composition of the present invention, the above-mentioned parts can be produced, for example, by the following method: various components of polybutylene terephthalate resin (A), polyethylene terephthalate resin (B), semi-crystalline resin and / or non-crystalline resin (C), inorganic reinforcing material (D) and various stabilizers, release agents or pigments as needed are mixed and melt-kneaded. The melt-kneading method can adopt any method well known to those skilled in the art, and a single-screw extruder, a twin-screw extruder, a pressure kneader, a Banbury mixer, etc. can be used. Among them, a twin-screw extruder can be preferably used. As general melt-kneading conditions, a twin-screw extruder is used, the barrel temperature is 240 to 290°C, and the kneading time is 2 to 15 minutes. In addition, only the inorganic reinforcing material or other components as needed can be added from a side feeder and melt-kneaded. The screw element combines a reverse kneading disk and a kneading disk between the main feeder and the side feeder, preferably applying high shear to melt the polyester resin. Furthermore, the molten polyester resin is preferably conveyed by forward flights, where it merges with the inorganic reinforcing material supplied from the side feeder and kneaded under low shear conditions. The molten polyester resin composition is then extruded from a die under low shear conditions and water-cooled to produce strands of the inorganic reinforced thermoplastic polyester resin composition. The resulting inorganic reinforced thermoplastic polyester resin composition is then vacuum-dried at, for example, 80°C for 12 hours and then molded to produce a molded article.

[0074] In addition, in the present invention, side feeder can be set at many places.The fiber length of the inorganic reinforcement material supplied from the upstream side feeder becomes shorter than the fiber length of the inorganic reinforcement material supplied from the downstream side feeder, by changing the supply amount of the inorganic reinforcement material of each side feeder, other extrusion conditions can be unchanged, and the fiber length in the composition can be easily adjusted within a given range. It is illustrated that the method for supplying from the original feeder (main feeder) and the side feeder is relatively easy to adjust the fiber length to be a single distribution (histogram is 1) and preferred due to the easier control of the distribution of fiber length.

[0075] The position of the side feeder supplying the inorganic reinforcement can be arbitrarily adjusted based on desired objectives, such as the amount of reinforcement, ease of mixing with the resin, and reinforcement fiber length. In the production of the inorganic reinforced thermoplastic polyester resin composition of the present invention, it is preferred to place the first side feeder at a distance no greater than one-quarter the distance between the main feeder and the die head, as this prevents excessive fiber shortening. Furthermore, it is preferred to place no more than five rollers between the side feeders (between the first and second side feeders), as this facilitates adjustment of the fiber length distribution to a uniform distribution (a single histogram).

[0076] In summary, the preferred embodiment of the method for producing an inorganic reinforced thermoplastic polyester resin composition of the present invention is to feed the same inorganic reinforcing material separately from multiple side feeders. In this case, the inorganic reinforcing material is preferably fed only from the multiple side feeders, not from the main feeder.

[0077] The number average molecular weight (Mn) of the resin component contained in the inorganic reinforced thermoplastic polyester resin composition of the present invention is preferably 5000 or more from the viewpoint of excellent mechanical properties of the molded article. If it is less than 5000, there is a problem of decreased mechanical strength. In addition, it is more preferably 7000 or more, and even more preferably 10000 or more. In addition, from the viewpoint of moldability, it is preferably 100000 or less. If it exceeds 100000, there is a problem of difficulty in improving the appearance of the molded article due to decreased moldability. It is more preferably 90000 or less, and even more preferably 80000 or less. In order to keep the number average molecular weight within a predetermined range, the set temperature of the extruder is preferably 270°C or less, and more preferably 265°C or less. In addition, the screw speed is preferably 500 rpm or less, and more preferably 400 rpm or less.

[0078] The number average molecular weight is determined by dissolving the sample in a mixed solvent of hexafluoroisopropanol (HFIP) and chloroform, filtering the sample solution through a membrane filter, and then performing gel permeation chromatography (GPC) using two TSKGel SuperHM-H and TSKGel SuperH2000 (TOSOH) columns connected in series. The number average molecular weight is relative to the molecular weight of standard polystyrene. The weight average molecular weight described below is determined using the same method.

[0079] The dispersity (Mw / Mn), expressed as the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn), of the resin components contained in the inorganic reinforced thermoplastic polyester resin composition of the present invention is preferably 5 or less. The dispersity is more preferably 4.8 or less, and even more preferably 4.5 or less. The lower limit of the dispersity is not particularly limited, but is theoretically 1.0 or greater. A dispersity exceeding 5 may cause gelation, adversely affecting fluidity. Furthermore, depending on the situation, the relatively high content of low-molecular-weight components may result, leading to a decrease in mechanical properties such as toughness.

[0080] Example

[0081] The present invention will be further described in detail below with reference to the following examples, but the present invention is not limited to these examples. In addition, the various characteristics and physical property values ​​shown in the following examples and comparative examples were measured by the following experimental methods.

[0082] (1) Reduced viscosity of polyester resin (dL / g):

[0083] 0.1 g of a sample was dissolved in 25 mL of a mixed solvent of phenol / tetrachloroethane (mass ratio 6 / 4), and the viscosity was measured at 30°C using an Ubbelohde viscometer.

[0084] (2) Bending strength:

[0085] The measurement was performed according to ISO-178.

[0086] (3) Flexural modulus:

[0087] The measurement was performed according to ISO-178.

[0088] (4) Charpy impact strength:

[0089] The measurement was performed in accordance with JIS K7111.

[0090] (5) Cooling crystallization temperature (Tc2N, Tc2M):

[0091] Using a differential scanning calorimeter (DSC), each sample was sealed in a DSC apparatus in a dry state with a moisture content of 0.03% or less by mass to prevent fluctuations due to moisture before measurement. Specifically, the temperature was raised to 300°C at a rate of 20°C / min under a nitrogen flow, held at this temperature for 5 minutes, and then cooled to 100°C at a rate of 10°C / min to obtain the peak temperature of the crystallization peak in the thermogram.

[0092] (6) 1mmt flow length:

[0093] Using a flow length evaluation mold having a flow path 10 mm wide and 1 mm thick, injection molding was performed with 20 consecutive injections at a cycle of 30 s at an injection pressure of 100 MPa, a barrel temperature of 275°C, and a mold temperature of 90°C. The flow length of the 20th shot was measured.

[0094] (7) Number average fiber length (Ln), weight average fiber length (Lw):

[0095] The length of the remaining glass fibers in the inorganic reinforced thermoplastic polyester resin composition is measured by the following method.

[0096] Because there is a lot of interference between glass fibers in a highly filled glass fiber material, the glass fibers are easily broken during measurement, making it difficult to obtain the correct fiber length. Therefore, in order to accurately measure the glass fiber length in the present invention, the pellets obtained by intensely heating and melting the kneaded particles at 650°C for 2 hours are removed as ash without breaking the glass fibers. The obtained glass fibers are immersed in water, the dispersed glass fibers are removed and placed on a slice, and more than 1,000 glass fibers are randomly selected and observed at 80 times using a digital microscope (KH-7700 manufactured by HIROX Co., Ltd.). The number average and weight average fiber lengths are obtained and are respectively referred to as the number average fiber length and weight average fiber length. In addition, the weight average fiber length (Lw) can be calculated using the following formula: pi (π), the number of fibers having the fiber length (Li), the density (ρi), and the fiber diameter (ri) as (Ni).

[0097] Lw=∑(Ni×π×ri 2 ×Li 2 ×ρi) / ∑(Ni×π×ri 2 ×Li×ρi)

[0098] Under the conditions of fixed fiber diameter and density, Lw can be calculated according to the following formula.

[0099] Lw=Σ(Ni×Li 2 ) / ∑(Ni×Li)

[0100] (8) Number of peaks in the fiber length histogram:

[0101] The glass fiber length measured by (7) is divided into stages of 50 μm each (0 to 50 μm, 50 to 100 μm, and the same intervals thereafter) to make a histogram, and the number of peaks at this time (stages higher than the stage heights on the left and right) is calculated as the number of peaks in the histogram.

[0102] (9) Number average molecular weight Mn and weight average molecular weight Mw of the resin component

[0103] A sample was weighed to a resin component concentration of approximately 0.05% by mass, dissolved in 0.4 ml of a solvent consisting of 3 / 2 (v / v) dichloromethane and HFIP, then diluted with 7.6 ml of chloroform and filtered through a 0.2 μm pore size membrane filter. The resulting sample solution was subjected to GPC analysis under the following conditions. Molecular weights were calculated using standard polystyrene conversion.

[0104] Device: TOSOH HLC-8320GPC

[0105] Chromatographic columns: SKGel SuperHM-H (2 columns) and TSKGel SuperH2000 (TOSOH) connected in series

[0106] Solvent: Chloroform / HFIP98 / 2 (v / v)

[0107] Flow rate: 0.6 ml / min, concentration: 0.05%

[0108] Injection volume: 20 μl, temperature: 40°C, detector: UV 254 nm

[0109] (10) Appearance of molded product A

[0110] Using a textured template mold of 100 mm × 100 mm × 2 mm (thickness), injection molding was performed in an injection molding machine at a resin temperature of 275-280°C and a mold temperature of 90°C. The obtained molded products were visually evaluated as follows.

[0111] ○: The surface of the molded article has no appearance defects due to floating glass fibers or misalignment of texture, which is good.

[0112] Δ: Floating glass fibers were observed at the end surface away from the gate.

[0113] ×: Floating glass fibers are visible throughout the entire molded product, and the surface gloss is poor.

[0114] (11) Appearance of molded product B

[0115] When a 18 mm × 180 mm × 2 mm strip molded product is formed by injection molding at a barrel temperature of 275 to 280°C and a mold temperature of 90°C, the molding is carried out within an injection molding speed range with a filling time of 1.6 seconds, and its appearance (floating glass fiber and sink marks) is visually observed.

[0116] ○: Good if there is no appearance defect due to floating fibers of glass fibers, sink marks, or jetting on the surface.

[0117] △: Some molded products (especially the end portions of the molded products) had slight appearance defects.

[0118] ×: Visually detectable appearance defects occurred

[0119] XX: In addition to visually detectable appearance defects, short shots were observed in some molded products.

[0120] (12) Warping of molded product C

[0121] Using a film gate mold with a size of 100mm x 100mm x 2mm (thickness) and a rib on one side, a molded product C having a rib structure of 100mm in length and 1mm in height with 5 ribs of 1mm in thickness in a direction perpendicular to the resin flow was molded in an injection molding machine at a resin temperature of 275-280°C and a mold temperature of 80°C, and its warpage was measured. Similarly, molded product C was molded at mold temperatures of 100°C and 120°C, and its warpage was measured. Figure 1 The value of A was evaluated based on the following criteria using the average value of three molded products at different mold temperatures.

[0122] ×: Warping deformation > 3mm

[0123] △: 3mm ≥ warping deformation ≥ 2mm

[0124] ○: Warping deformation <2mm

[0125] (13) Warping of molded product D

[0126] Except for using a mold with a 100mm×100mm×1.5mm (thickness) film gate with ribs on one side, molding was carried out in the same manner as (12) to obtain molded product D, and its warpage deformation was measured and evaluated under the same standard.

[0127] In addition, the raw materials used in the examples and comparative examples are as follows:

[0128] (A) polybutylene terephthalate resin;

[0129] Made by Toyobo Co., Ltd., reduced viscosity 0.70dL / g

[0130] (B) polyethylene terephthalate resin;

[0131] Made by Toyobo Co., Ltd., reduced viscosity 0.72dL / g

[0132] (C) semi-crystalline resin and / or non-crystalline resin;

[0133] (C1) Copolymerized polyethylene terephthalate resin:

[0134] A copolymer having a composition ratio of TPA / EG / NPG = 100 / 70 / 30 (mol%), manufactured by Toyobo Co., Ltd., with a reduced viscosity of 0.83 dL / g

[0135] (C2) Copolymerized polyethylene terephthalate resin:

[0136] A copolymer with a composition ratio of TPA / IPA / / EG / NPG = 50 / 50 / / 50 / 50 (mol%), manufactured by Toyobo Co., Ltd., with a reduced viscosity of 0.53 dL / g

[0137] (The English abbreviations represent the following ingredients: TPA: terephthalic acid; IPA: isophthalic acid; EG: ethylene glycol; NPG: neopentyl glycol)

[0138] (C3) Polycarbonate

[0139] "CALIBRE 301-40", manufactured by Sumika Stylon Polycarbonate Co., Ltd., has a melt volume flow rate (300°C, load 1.2 kg) of 40 cm 3 / 10min

[0140] (D) Inorganic reinforcing materials;

[0141] (D1) Glass fiber:

[0142] T-127H, manufactured by Nippon Electric Glass Co., Ltd., average fiber length 3mm, average fiber diameter 11μm

[0143] transesterification inhibitors;

[0144] ADEKASTAB AX-71, manufactured by ADEKA

[0145] Other additives;

[0146] Antioxidant: Irganox 1010 (manufactured by BASF Japan)

[0147] Release agent: Licolub WE40 (manufactured by Clariant Japan)

[0148] Black pigment: ABF-T-9534 (manufactured by RESINOCOLOR Industries, Ltd.)

[0149] Examples 1 to 3, 5 to 9, Comparative Examples 1, 2, and 5

[0150] Method for producing inorganic reinforced thermoplastic polyester resin compositions according to Examples and Comparative Examples: The raw materials were weighed according to the mixing ratios (parts by mass) shown in Table 1. A main feeder was installed at the No. 1 roll on the upstream side of the extruder, and further, a first side feeder was installed at the No. 5 roll, and a second side feeder was installed at the No. 9 roll. The materials were melt-kneaded using a twin-screw extruder (TEX44α, manufactured by Japan Steel Works, Ltd.) with an L / D ratio of 49 (number of rolls: 17) at a barrel temperature of 260°C and a screw speed of 300 rpm. Raw materials other than the inorganic reinforcing material were fed into the twin-screw extruder from the main feeder's feed port. The inorganic reinforcing material was fed into the twin-screw extruder from the main feeder or the side feeder in the amounts shown in Table 1.

[0151] The pellets of the inorganic reinforced thermoplastic polyester resin composition were dried to a moisture content of 800 ppm or less and then subjected to the above-mentioned various moldings and evaluations.

[0152] The molding conditions were: a cylinder temperature of 275° C. when the reinforcing material content was less than 40 parts by mass, and 280° C. when the reinforcing material content was greater than 40 parts by mass. The evaluation results are shown in Table 1.

[0153] Example 4, Comparative Examples 3 and 4

[0154] Melt kneading, molding, and evaluation were carried out in the same manner as in Example 1, except that the barrel temperature of the twin-screw extruder was changed to 275° C. and the screw speed was changed to 550 rpm.

[0155] Example 10

[0156] Melt kneading, molding, and evaluation were carried out in the same manner as in Example 1, except that the first side feeder was provided on the seventh roller.

[0157] In each of the Examples and Comparative Examples, an inorganic reinforced thermoplastic polyester resin composition not containing (C) a semi-crystalline resin and / or amorphous resin was prepared, and Tc2N was measured.

[0158]

[0159] Industrial Application Possibilities

[0160] The inorganic reinforced thermoplastic polyester resin composition of the present invention can be used to produce molded products with excellent appearance while maintaining inherent mechanical properties such as rigidity and impact resistance in long, thin-walled molding. Therefore, it can be used in a wide range of applications, from air conditioner fans to automotive interior and exterior parts, various mechanical structural parts, and other exterior parts requiring high rigidity, such as housings and casings. Therefore, it is of great benefit to the industry.

Claims

1. An inorganic reinforced thermoplastic polyester resin composition, characterized in that It contains: 20 to 55 parts by mass of a polybutylene terephthalate resin (A), 1 to 30 parts by mass of a polyethylene terephthalate resin (B), 3 to 30 parts by mass of a semi-crystalline resin and / or a non-crystalline resin (C), and 25 to 65 parts by mass of an inorganic reinforcing material (D); The inorganic reinforced thermoplastic polyester resin composition has an average fiber length Ln of 100 to 500 μm. The flow length of the inorganic reinforced thermoplastic polyester resin composition is 80 mm or more, The number average fiber length Ln and weight average fiber length Lw of the inorganic reinforcing material (D) in the inorganic reinforced thermoplastic polyester resin composition satisfy Lw / Ln≤2.0, The semi-crystalline resin and / or non-crystalline resin (C) is one or more selected from copolymerized polybutylene terephthalate, copolymerized polyethylene terephthalate, and polycarbonate resins. The inorganic reinforced thermoplastic polyester resin composition has a cooling crystallization temperature Tc2M determined using a differential scanning calorimeter DSC in the range of 160°C ≤ Tc2M ≤ 185°C. The cooling crystallization temperature Tc2M is obtained by sealing the inorganic reinforced thermoplastic polyester resin composition in a dry state with a moisture content of less than 0.03% by mass into a DSC device, heating it to 300°C at a heating rate of 20°C / min under a nitrogen flow, maintaining it at this temperature for 5 minutes, and then cooling it to 100°C at a rate of 10°C / min to obtain the top temperature of the crystallization peak in the thermal spectrum.

2. The inorganic reinforced thermoplastic polyester resin composition according to claim 1, characterized in that The semi-crystalline resin and / or non-crystalline resin (C) is at least one selected from terephthalic acid / ethylene glycol / neopentyl glycol copolymer, terephthalic acid / ethylene glycol / 1,2-propylene glycol copolymer, and terephthalic acid / isophthalic acid / ethylene glycol / neopentyl glycol copolymer.

3. The inorganic reinforced thermoplastic polyester resin composition according to claim 1 or 2, characterized in that: For the polyester resin composition that does not contain the semi-crystalline resin and / or the amorphous resin (C) in the inorganic reinforced thermoplastic polyester resin composition, when its cooling crystallization temperature Tc2N is determined using a differential scanning calorimeter DSC, the following relationship is satisfied: Tc2N-Tc2M≥10℃, The cooling crystallization temperature Tc2N is obtained by sealing the inorganic reinforced thermoplastic polyester resin composition in a dry state with a moisture content of less than 0.03% by mass into a DSC device, heating it to 300°C at a heating rate of 20°C / min under a nitrogen flow, maintaining it at this temperature for 5 minutes, and then cooling it to 100°C at a rate of 10°C / min to obtain the top temperature of the crystallization peak in the thermal spectrum. The unit of Tc2N is °C.

4. The inorganic reinforced thermoplastic polyester resin composition according to claim 1 or 2, characterized in that: The weight average molecular weight Mw and number average molecular weight Mn of the resin component of the inorganic reinforced thermoplastic polyester resin composition satisfy Mw / Mn≤5.

5. The inorganic reinforced thermoplastic polyester resin composition according to claim 1 or 2, characterized in that: The content of the inorganic reinforcing material (D) in the inorganic reinforced thermoplastic polyester resin composition is 40 to 60% by mass.

6. A method for producing the inorganic reinforced thermoplastic polyester resin composition according to any one of claims 1 to 5, characterized in that: A twin-screw extruder equipped with multiple side feeders is used, and the same inorganic reinforcing material is fed separately from the multiple side feeders.

Images