A polybutylene terephthalate resin composition, a method for preparing the same, and an application thereof

Abstract

The present application relates to a kind of polybutylene terephthalate resin composition and its preparation method and application, the polybutylene terephthalate resin composition includes biobased polybutylene terephthalate resin, titanium element, phosphorus element and cobalt element;The weight content of titanium element in the polybutylene terephthalate resin composition is 20-150ppm, the weight content of phosphorus element is 2-50ppm, the weight content of cobalt element is 4-100ppm;The mass ratio of titanium element, phosphorus element and cobalt element in the polybutylene terephthalate resin composition is (2-20):(1-2):(1-10).The polybutylene terephthalate resin composition provided by the present application, by controlling the weight content and mass ratio of titanium element, phosphorus element and cobalt element within suitable range, can make polybutylene terephthalate resin composition have high whiteness, excellent mechanical properties and aging resistance.

Description

Technical Field

[0001] This invention belongs to the field of bio-based plastics technology, specifically relating to a polybutylene terephthalate resin composition, its preparation method, and its application. Background Technology

[0002] Polybutylene terephthalate (PBT), a typical engineering plastic, possesses excellent mechanical, electrical, heat resistance, and processing properties, and is widely used in industries such as electronics, automobiles, machinery, and home appliances. Traditional PBT is produced using petroleum-based raw materials; however, facing the severe situation of dwindling fossil resources and increasingly severe environmental pollution, a shift towards using environmentally friendly and efficient renewable biological resources as raw materials is an inevitable trend.

[0003] Bio-based materials refer to biomass synthetic materials, biomass recycled materials, and basic chemical raw materials obtained through biosynthesis, bioprocessing, and biorefining processes using renewable resources as raw materials. Currently, bio-based materials are mainly used in the production of plastics, fibers, nylon, and rubber, and are characterized by renewable raw materials, biodegradability, and low levels of harmful substances generated during processing. Bio-based materials are a key area for the development of modern bio-manufacturing industry and a major industrial direction for green socio-economic growth. The large-scale development of bio-based materials will reduce the chemical materials industry's dependence on fossil resources, contributing to environmental improvement and coordinated economic development. It is of great significance for accelerating the cultivation of strategic emerging industries, promoting the transformation and upgrading of my country's petrochemical materials industry, driving green economic growth, and promoting agricultural-industrial integration and urbanization.

[0004] Currently, the use of bio-based materials to replace petroleum-based materials in the preparation of bio-based PBT resin has received increasing attention. However, impurities in bio-based materials can affect the color value of bio-based PBT resin, resulting in lower whiteness and a tendency to yellow, which affects the use of bio-based PBT resin. Therefore, it is imperative to develop a bio-based PBT resin with high whiteness, excellent mechanical properties, and good aging resistance. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a polybutylene terephthalate resin composition, its preparation method and application. By controlling the weight content and mass ratio of titanium, phosphorus and cobalt elements in the polybutylene terephthalate resin composition within a suitable range, the polybutylene terephthalate resin composition can have high whiteness and excellent mechanical properties, as well as excellent aging resistance.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a polybutylene terephthalate resin composition, wherein the polybutylene terephthalate resin composition comprises bio-based polybutylene terephthalate resin, titanium, phosphorus and cobalt; the weight content of titanium in the polybutylene terephthalate resin composition is 20-150 ppm, the weight content of phosphorus is 2-50 ppm, and the weight content of cobalt is 4-100 ppm; the mass ratio of titanium, phosphorus and cobalt in the polybutylene terephthalate resin composition is (2-20):(1-2):(1-10).

[0008] In this invention, titanium in the polybutylene terephthalate (PBT) resin composition can catalyze the synthesis of the PBT resin composition, phosphorus acts as a stabilizer, and cobalt acts as both a catalyst and a regulator of the whiteness of the PBT resin composition. If the titanium content is too low, the synthesized bio-based PBT resin will have a low molecular weight and poor performance; if the titanium content is too high, it will affect the aging resistance of the PBT resin composition. If the phosphorus content is too low, it will not act as a stabilizer; if the phosphorus content is too high, the acid value of the PBT resin composition will increase, thus affecting its aging resistance. If the cobalt content is too low, the color of the PBT resin composition will tend to be yellowish; if the cobalt content is too high, it will affect the aging resistance of the PBT resin composition. The mass ratio of titanium, phosphorus, and cobalt in the PBT resin composition needs to be controlled within a suitable range; exceeding this range will affect the acid value, whiteness, mechanical properties, and aging resistance of the PBT resin composition.

[0009] In this invention, the weight content of titanium, phosphorus and cobalt in the polybutylene terephthalate resin composition was determined by ICP-OES analysis according to US EPA method 3052:1996, following the procedure below: 0.1 g of the polybutylene terephthalate resin composition was weighed, pulverized, and 5 mL of nitric acid was added to completely submerge the polybutylene terephthalate resin composition. Then, 1.0 mL of hydrogen peroxide was added dropwise and reacted for 2 min. The mixture was then sealed in a microwave digestion vessel and digested at 210 °C for 3 h. After cooling to room temperature, the mixture was filtered through a 0.45 μm filter membrane and diluted with distilled water to 50 mL. The final result was obtained by ICP-OES (Spectro arcos FHS12 inductively coupled plasma emission spectrometer, Ametek, USA).

[0010] In this invention, the term "bio-based polybutylene terephthalate resin" refers to a polybutylene terephthalate resin obtained by polymerization based on bio-based monomers, wherein the bio-based monomers include bio-based 1,4-butanediol and / or bio-based terephthalic acid.

[0011] The titanium content in the polybutylene terephthalate resin composition is 20-150 ppm by weight, for example, it can be 20 ppm, 25 ppm, 30 ppm, 35 ppm, 40 ppm, 45 ppm, 50 ppm, 55 ppm, 60 ppm, 65 ppm, 70 ppm, 75 ppm, 80 ppm, 85 ppm, 90 ppm, 95 ppm, 100 ppm, 105 ppm, 110 ppm, 115 ppm, 120 ppm, 125 ppm, 130 ppm, 135 ppm, 140 ppm, 145 ppm, 150 ppm, etc.

[0012] The phosphorus content is 2-50 ppm by weight, for example, it can be 2 ppm, 5 ppm, 10 ppm, 15 ppm, 20 ppm, 25 ppm, 30 ppm, 35 ppm, 40 ppm, 45 ppm, 50 ppm, etc.

[0013] The weight content of the cobalt element is 4-100 ppm, for example, it can be 4 ppm, 10 ppm, 15 ppm, 20 ppm, 25 ppm, 30 ppm, 35 ppm, 40 ppm, 45 ppm, 50 ppm, 55 ppm, 60 ppm, 65 ppm, 70 ppm, 75 ppm, 80 ppm, 85 ppm, 90 ppm, 95 ppm, or 100 ppm.

[0014] The mass ratio of titanium, phosphorus, and cobalt in the polybutylene terephthalate resin composition is (2-20):(1-2):(1-10), for example, it can be 2.5:1.1:1, 3:1.2:1.2, 4:1.3:1.5, 5:1.4:2, 6:1.5:2.5, 7:1.6:3, 8:1.7:3.5, 9:1.8:4, 10:1.9:4.5, 11:1.91:5, 12:1.92:5.5, 13:1.93:6, 14:1.94:6.5, 15:1.95:7, 16:1.96:7.5, 17:1.97:8, 18:1.98:8.5, 19:1.99:9, 19.5:2:9.5, etc.

[0015] This invention does not impose any particular limitation on the source of phosphorus in the polybutylene terephthalate (PPT) resin composition. It can originate from added phosphorus-containing compounds, non-added phosphorus-containing compounds such as phosphorus impurities in the raw materials, or a combination of both. Furthermore, the production processes of raw materials from different manufacturers (such as those used to prepare bio-based PPT resin) vary, and the raw materials may be contaminated during storage, transportation, transfer, and processing, resulting in differences in the phosphorus content of the final PPT resin composition.

[0016] This invention does not impose any particular limitation on the source of titanium in the polybutylene terephthalate (PET) resin composition. It can originate from added titanium-containing compounds, non-added titanium-containing compounds such as titanium-containing impurities in the raw materials, or a combination of both. Furthermore, the production processes of raw materials from different manufacturers (such as those used to prepare bio-based PET resin) differ, and the raw materials may be contaminated during storage, transportation, transfer, and processing, resulting in variations in the titanium content of the final PET resin composition.

[0017] This invention does not impose any particular limitation on the source of cobalt in the polybutylene terephthalate (PET) resin composition. It can originate from added cobalt-containing compounds, non-added cobalt-containing compounds such as cobalt impurities in the raw materials, or a combination of both. Furthermore, the production processes of raw materials from different manufacturers (such as those used to prepare bio-based PET resin) vary, and the raw materials may be contaminated during storage, transportation, transfer, and processing, resulting in variations in the cobalt content of the final PET resin composition.

[0018] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0019] As a preferred technical solution, the mass ratio of titanium, phosphorus and cobalt in the polybutylene terephthalate resin composition is (3-15):(1.1-1.5):(1-8), for example, it can be 3.5:1.1:1.5, 4:1.15:2, 5:1.2:2.5, 6:1.25:3, 7:1.3:3.5, 8:1.35:4, 9:1.4:4.5, 10:1.45:5, 11:1.5:5.5, 12:1.5:6, 13:1.5:7, 14:1.5:8, etc.

[0020] The preferred mass ratio of titanium, phosphorus, and cobalt in the polybutylene terephthalate resin composition is (4-10):(1.2-1.4):(2-6), for example, it can be 4:1.2:2.5, 4.5:1.25:3, 5:1.3:3.5, 6:1.35:4, 7:1.4:4.5, 8:1.4:5, 9:1.4:5.5, 9:1.4:6, etc.

[0021] Preferably, the titanium content in the polybutylene terephthalate resin composition is 30-100 ppm by weight, for example, it can be 30 ppm, 35 ppm, 40 ppm, 45 ppm, 50 ppm, 55 ppm, 60 ppm, 65 ppm, 70 ppm, 75 ppm, 80 ppm, 85 ppm, 90 ppm, 95 ppm, 100 ppm, etc.

[0022] Preferably, the phosphorus content in the polybutylene terephthalate resin composition is 5-30 ppm by weight, for example, 5 ppm, 6 ppm, 8 ppm, 10 ppm, 12 ppm, 14 ppm, 16 ppm, 18 ppm, 20 ppm, 22 ppm, 24 ppm, 26 ppm, 28 ppm, 30 ppm, etc.

[0023] Preferably, the cobalt content in the polybutylene terephthalate resin composition is 10-80 ppm by weight, for example, 10 ppm, 15 ppm, 20 ppm, 25 ppm, 30 ppm, 35 ppm, 40 ppm, 45 ppm, 50 ppm, 55 ppm, 60 ppm, 65 ppm, 70 ppm, 75 ppm, 80 ppm, etc.

[0024] Preferably, according to ISO 1133 standard, under the conditions of 250°C and 2.16 kg weight, the melt index of the polybutylene terephthalate resin composition is ≤70 g / 10 min, for example, it can be 2 g / 10 min, 4 g / 10 min, 6 g / 10 min, 8 g / 10 min, 10 g / 10 min, 12 g / 10 min, 14 g / 10 min, 16 g / 10 min, 20 g / 10 min, 25 g / 10 min, 30 g / 10 min, 35 g / 10 min, 40 g / 10 min, 45 g / 10 min, 50 g / 10 min, 55 g / 10 min, 60 g / 10 min, 65 g / 10 min, 70 g / 10 min, etc.

[0025] Preferably, according to ISO 1133 standard, under conditions of 250°C and 2.16 kg weight, the melt index of the polybutylene terephthalate resin composition is 10-69 g / 10 min (e.g., 10 g / 10 min, 15 g / 10 min, 20 g / 10 min, 25 g / 10 min, 30 g / 10 min, 35 g / 10 min, 40 g / 10 min, 45 g / 10 min, 50 g / 10 min, 55 g / 10 min, 60 g / 10 min, 65 g / 10 min, 66 g / 10 min, 6...). 7g / 10min, 68g / 10min, etc.), and more preferably 20-60g / 10min (e.g., 21g / 10min, 23g / 10min, 27g / 10min, 29g / 10min, 31g / 10min, 33g / 10min, 37g / 10min, 39g / 10min, 41g / 10min, 43g / 10min, 47g / 10min, 49g / 10min, 51g / 10min, 53g / 10min, 57g / 10min, 59g / 10min, etc.).

[0026] Preferably, the number average molecular weight of the bio-based polybutylene terephthalate resin is 20,000-50,000 g / mol, for example, it can be 20,000 g / mol, 22,000 g / mol, 24,000 g / mol, 26,000 g / mol, 28,000 g / mol, 30,000 g / mol, 32,000 g / mol, 34,000 g / mol, 36,000 g / mol, 38,000 g / mol, 40,000 g / mol, 42,000 g / mol, 44,000 g / mol, 46,000 g / mol, 48,000 g / mol, etc.

[0027] More preferably, the number average molecular weight of the bio-based polybutylene terephthalate resin is 20,000-45,000 g / mol, for example, it can be 21,000 g / mol, 23,000 g / mol, 25,000 g / mol, 27,000 g / mol, 29,000 g / mol, 31,000 g / mol, 33,000 g / mol, 35,000 g / mol, 37,000 g / mol, 39,000 g / mol, 41,000 g / mol, 43,000 g / mol, 45,000 g / mol, etc.

[0028] Preferably, the L value of the polybutylene terephthalate resin composition is ≥88.0 (e.g., it can be 88.2, 88.4, 88.6, 88.8, 89, 89.2, 89.4, 89.6, 89.8, 90, 90.2, 90.4, 90.6, 90.8, 91, 91.5, 92, 92.5, 93, 93.5, 94, 94.5, 95, 95.5, 96, 96.5, 97, 97.5, 98, 98.5, 99, 99.5, etc.). The value of b is ≤3.0 (for example, it can be -0.9, -0.8, -0.7, -0.6, -0.5, -0.4, -0.3, -0.2, -0.1, 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, etc.).

[0029] Preferably, the tensile strength of the polybutylene terephthalate resin composition is ≥58MPa, for example, it can be 58MPa, 58.5MPa, 59MPa, 59.5MPa, 60MPa, 60.5MPa, 61MPa, 61.5MPa, 62MPa, 62.5MPa, 63MPa, etc.

[0030] Preferably, the flexural modulus of the polybutylene terephthalate resin composition is 58.5-61 MPa, for example, it can be 58.5 MPa, 58.6 MPa, 58.7 MPa, 58.8 MPa, 58.9 MPa, 59 MPa, 59.1 MPa, 59.2 MPa, 59.3 MPa, 59.4 MPa, 59.5 MPa, 59.6 MPa, 59.7 MPa, 59.8 MPa, 59.9 MPa, 60 MPa, 60.1 MPa, 60.2 MPa, 60.3 MPa, 60.4 MPa, 60.5 MPa, 60.6 MPa, 60.7 MPa, 60.8 MPa, 60.9 MPa, 61 MPa, etc.

[0031] In a second aspect, the present invention provides a method for preparing a polybutylene terephthalate resin composition as described in the first aspect, the method comprising the following steps:

[0032] (1) Terephthalic acid, 1,4-butanediol and titanium-containing compound are reacted to obtain a first mixture; at least one of the terephthalic acid and 1,4-butanediol is a bio-based material;

[0033] (2) The first mixture, the phosphorus-containing compound, and the cobalt-containing compound are reacted to obtain a second mixture;

[0034] (3) The second mixture is reacted to obtain the polybutylene terephthalate resin composition.

[0035] In this invention, the bio-based materials refer to biomass synthetic materials, biomass regenerated materials, and basic chemical raw materials obtained from renewable resources, such as starch and cellulose, through bio-fermentation, bio-synthesis, bio-processing, and bio-refining processes, including bio-based 1,4-butanediol and / or bio-based terephthalic acid.

[0036] Preferably, the molar ratio of terephthalic acid to 1,4-butanediol in step (1) is 1:(1.2-1.5), for example, it can be 1:1.22, 1:1.24, 1:1.26, 1:1.28, 1:1.3, 1:1.32, 1:1.34, 1:1.36, 1:1.38, 1:1.4, 1:1.42, 1:1.44, 1:1.46, 1:1.48, etc.

[0037] Preferably, based on the total mass of the terephthalic acid and 1,4-butanediol being 100%, the mass of the titanium-containing compound is 0.01-0.089%, for example, it can be 0.015%, 0.02%, 0.025%, 0.03%, 0.035%, 0.04%, 0.045%, 0.05%, 0.055%, 0.06%, 0.065%, 0.07%, 0.075%, 0.08%, 0.085%, etc.

[0038] Preferably, based on the total mass of the terephthalic acid and 1,4-butanediol as 100%, the mass of the phosphorus-containing compound is 0.0018-0.0442%, for example, it can be 0.002%, 0.004%, 0.006%, 0.008%, 0.01%, 0.015%, 0.018%, 0.02%, 0.022%, 0.025%, 0.028%, 0.03%, 0.032%, 0.035%, 0.038%, 0.04%, 0.042%, 0.044%, etc.

[0039] Preferably, based on the total mass of the terephthalic acid and 1,4-butanediol being 100%, the mass of the cobalt-containing compound is 0.0011-0.0251%, for example, it can be 0.0015%, 0.002%, 0.0025%, 0.003%, 0.0035%, 0.004%, 0.0045%, 0.005%, 0.0055%, 0.006%, 0.0065%, 0.007%, 0.008%, 0.009%, 0.01%, 0.012%, 0.014%, 0.016%, 0.018%, 0.02%, 0.022%, 0.024%, etc.

[0040] Preferably, the phosphorus-containing compound includes any one or a combination of at least two of phosphoric acid, phosphorous acid, hypophosphite, phosphate, alkyl phosphate, or triphenyl phosphate.

[0041] Preferably, the alkyl phosphate ester includes any one or a combination of at least two of triethyl phosphate, trimethyl phosphate, tributyl phosphate, trioctyl phosphate, or trihexyl phosphate.

[0042] Preferably, the cobalt-containing compound includes any one or a combination of at least two of inorganic cobalt salts, cobalt oxides, or organic cobalt.

[0043] Preferably, the inorganic cobalt salt includes any one or a combination of at least two of cobalt chloride, cobalt sulfate, or cobalt bromide.

[0044] Preferably, the cobalt oxide comprises cobalt trioxide and / or cobalt pentoxide.

[0045] Preferably, the organic cobalt comprises any one or a combination of at least two of cobalt acetate, cobalt glycolate, or cobalt triacetate.

[0046] Preferably, the titanium-containing compound has the general formula Ti(OR)4; wherein R is selected from at least one of C1-C10 straight-chain or branched alkyl groups and C6-C10 aryl groups.

[0047] In this invention, C1-C10 can be C1, C2, C3, C4, C5, C6, C7, C8, C9 or C10.

[0048] The C1-C10 straight-chain or branched alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, pteropentyl, n-hexyl, n-octyl, n-heptyl, n-nonyl, n-decyl, etc.

[0049] The C6-C10 can be C6, C7, C8, C9 or C10.

[0050] The C6-C10 aryl groups include, but are not limited to, phenyl or naphthyl groups.

[0051] Preferably, the titanium-containing compound includes tetrabutyl titanate and / or isopropyl titanate.

[0052] Preferably, the pressure of the reaction in step (1) is 30-100 kPa, for example, it can be 30 kPa, 35 kPa, 40 kPa, 45 kPa, 50 kPa, 55 kPa, 60 kPa, 65 kPa, 70 kPa, 75 kPa, 80 kPa, 85 kPa, 90 kPa, 95 kPa, 100 kPa, etc.

[0053] Preferably, the reaction temperature in step (1) is 180-250℃, for example, it can be 180℃, 182℃, 185℃, 188℃, 190℃, 192℃, 195℃, 198℃, 200℃, 205℃, 210℃, 215℃, 220℃, 225℃, 230℃, 235℃, 240℃, 245℃, 250℃, etc.

[0054] Preferably, the reaction time in step (1) is 1-5 hours, for example, 1 hour, 1.2 hours, 1.5 hours, 1.8 hours, 2 hours, 2.2 hours, 2.5 hours, 2.8 hours, 3 hours, 3.2 hours, 3.5 hours, 3.8 hours, 4 hours, 4.2 hours, 4.5 hours, 4.8 hours, 5 hours, etc.

[0055] Preferably, the 1,4-butanediol is a bio-based 1,4-butanediol.

[0056] Preferably, the reaction in step (2) is carried out under a nitrogen atmosphere.

[0057] Preferably, the reaction temperature in step (2) is 180-250℃, for example, it can be 180℃, 182℃, 185℃, 188℃, 190℃, 192℃, 195℃, 198℃, 200℃, 205℃, 210℃, 215℃, 220℃, 225℃, 230℃, 235℃, 240℃, 245℃, 250℃, etc.

[0058] Preferably, the reaction time in step (2) is 10-30 min, for example, it can be 10 min, 12 min, 14 min, 16 min, 18 min, 20 min, 22 min, 24 min, 26 min, 28 min, 30 min, etc.

[0059] Preferably, the reaction temperature in step (3) is 230-260℃, for example, it can be 230℃, 232℃, 234℃, 236℃, 238℃, 240℃, 242℃, 244℃, 246℃, 248℃, 250℃, 252℃, 254℃, 256℃, 258℃, 260℃, etc.

[0060] Preferably, the reaction time in step (3) is 3-6 hours, for example, 3 hours, 3.2 hours, 3.4 hours, 3.5 hours, 3.6 hours, 3.8 hours, 4 hours, 4.2 hours, 4.4 hours, 4.5 hours, 4.6 hours, 4.8 hours, 5 hours, 5.2 hours, 5.4 hours, 5.6 hours, 5.8 hours, 6 hours, etc.

[0061] Preferably, the pressure of the reaction in step (3) is <200 Pa, for example, it can be 1 Pa, 5 Pa, 10 Pa, 20 Pa, 30 Pa, 40 Pa, 50 Pa, 60 Pa, 70 Pa, 80 Pa, 90 Pa, 100 Pa, 110 Pa, 120 Pa, 130 Pa, 140 Pa, 150 Pa, 160 Pa, 170 Pa, 180 Pa, 190 Pa, etc.

[0062] Preferably, after the reaction in step (3) is completed, a granulation step is also included.

[0063] Thirdly, the present invention provides the application of the polybutylene terephthalate resin composition as described in the first aspect in electronic appliances, household appliances, new energy equipment, intelligent equipment, relays or communication connectors.

[0064] Compared with the prior art, the present invention has the following beneficial effects:

[0065] The polybutylene terephthalate resin composition provided by this invention has high whiteness, is not prone to yellowing, has a b value of 1.0-2.9, an L value of 88.1-89.8, and excellent mechanical properties and aging resistance. The tensile strength can reach 58.6-60.6 MPa, and the retention rate of tensile strength after aging treatment can reach 90.0-92.8%. Detailed Implementation

[0066] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0067] The sources of some components in the examples and comparative examples are as follows:

[0068] (1) Bio-based 1,4-butanediol: purchased from Yuanli Chemical Group Co., Ltd., with a purity of ≥99.5%;

[0069] (2) Terephthalic acid: purchased from Zhuhai INEOS Chemical Co., Ltd., with a purity of ≥99.9%;

[0070] (3) Tetrabutyl titanate: purchased from Tianjin Kemeio Reagent, purity ≥99.0%;

[0071] (4) Isopropyl titanate: purchased from Tianjin Kemeio Reagent, purity ≥99.0%;

[0072] (5) Triphenyl phosphate: purchased from Aladdin Reagent, purity ≥98.0%;

[0073] (6) Trimethyl phosphate: purchased from Aladdin Reagent, purity ≥98.0%;

[0074] (7) Cobalt acetate: purchased from Aladdin Reagent, purity ≥99.0%;

[0075] (8) Cobalt trioxide: purchased from Aladdin Reagent, purity ≥99.0%.

[0076] Example 1

[0077] A polybutylene terephthalate resin composition, the raw material components and their amounts are shown in Table 1; the preparation method of the polybutylene terephthalate resin composition includes the following steps:

[0078] (1) Terephthalic acid, bio-based 1,4-butanediol and titanium-containing compound were mixed and kept at a pressure of 40 kPa and a temperature of 230 °C for 1.5 h to obtain the first mixture;

[0079] (2) Nitrogen gas was introduced into the first mixture, and phosphorus-containing compounds and cobalt-containing compounds were added. The mixture was kept for 20 minutes to obtain the second mixture.

[0080] (3) The pressure of the second mixture is reduced to 100 Pa, heated to 250 °C, maintained for 4.5 h, nitrogen is introduced, and granulation is performed to obtain the polybutylene terephthalate resin composition.

[0081] The contents of titanium, phosphorus and cobalt in the polybutylene terephthalate resin composition obtained in Example 1, the number-average molecular weight of the bio-based polybutylene terephthalate resin and the performance test results of the resin composition are shown in Table 3.

[0082] Examples 2-9, Comparative Examples 1-11

[0083] A polybutylene terephthalate resin composition, the raw materials for its preparation and the selection of titanium-containing compounds, phosphorus-containing compounds and cobalt-containing compounds are shown in Tables 1 and 2, wherein "-" indicates that the substance was not used; the preparation methods of the polybutylene terephthalate resin compositions provided in Examples 2-8 and Comparative Examples 1-11 are as described in Example 1;

[0084] The preparation method of the polybutylene terephthalate resin composition provided in Example 9 includes the following steps:

[0085] (1) Terephthalic acid, bio-based 1,4-butanediol and cobalt acetate were mixed and kept at a pressure of 40 kPa and a temperature of 230 °C for 1.5 h to obtain the first mixture;

[0086] (2) Nitrogen gas was introduced into the first mixture, and triphenyl phosphate and tetrabutyl titanate were added. The mixture was kept for 20 minutes to obtain the second mixture.

[0087] (3) The pressure of the second mixture is reduced to 100 Pa, heated to 250 °C, maintained for 4.5 h, nitrogen is introduced, and granulation is performed to obtain the polybutylene terephthalate resin composition.

[0088] Table 1

[0089]

[0090] Table 2

[0091]

[0092]

[0093] Performance testing

[0094] (1) Determination of the weight content of titanium, phosphorus and cobalt in polybutylene terephthalate resin composition: ICP-OES analysis was performed according to US EPA method 3052:1996, and the following procedure was followed: 0.1 g of polybutylene terephthalate resin composition was weighed, crushed and then 5 mL of nitric acid was added to completely immerse the polybutylene terephthalate resin composition. Then 1.0 mL of hydrogen peroxide was added and reacted for 2 min. The mixture was sealed in a microwave digestion vessel and digested at 210 °C for 3 h. After cooling to room temperature, the mixture was filtered through a 0.45 μm filter membrane and diluted with distilled water to 50 mL. The result was obtained by ICP-OES (Spectro arcos FHS12 inductively coupled plasma emission spectrometer, Ametek Corporation, USA).

[0095] (2) Melt flow index: The melt flow index was tested using a Zwick C-FLOW instrument according to ISO 1133 at 250°C and with a 2.16 kg weight. The unit is g / 10 min.

[0096] (3) Number average molecular weight of bio-based polybutylene terephthalate resin: Approximately 200 mg of bio-based polybutylene terephthalate resin was dissolved in 4 mL of chromatographic grade hexafluoroisopropanol and allowed to stand for at least 8 hours. After complete dissolution, 0.25 mL of the solution was taken and 4.75 mL of chromatographic grade hexafluoroisopropanol was added. The mixture was mixed thoroughly and allowed to stand for at least 8 hours. The solution was filtered through a PTFE filter with a pore size of 0.45 μm. GPC testing was performed using Shimadzu instruments with RID-6A and SPD-10A detectors. The column temperature was 40 °C, the solvent was hexafluoroisopropanol, and the flow rate was 0.51 mL / min.

[0097] (4) Whiteness: The Lab value test is a color description method based on the Lab color space recommended by CIE (International Commission on Illumination). It converts color from a three-dimensional space (chromaticity, brightness and saturation) to a two-dimensional space (Lab value), thereby achieving a unified description of color. According to the standard CIE 1976 (L*a*b*), the b value and L value are obtained by testing with a colorimeter (Weifu Optoelectronics WF-30).

[0098] (5) Tensile strength: In accordance with ISO 178-2010 standard, the sample to be tested was injection molded into a specimen, and the tensile strength after injection molding was tested using a tensile testing machine (zwick ProLine);

[0099] (6) Aging resistance: Parallel specimens of tensile strength were aged at 85℃ and 85%RH for 1000h, and then the tensile strength of the specimens after aging was tested using a tensile testing machine (Zwick ProLine), and the retention rate of tensile strength before and after aging was calculated.

[0100] The polybutylene terephthalate resin compositions provided in Examples 1-9 and Comparative Examples 1-11 were tested according to the above method, and the test results are shown in Table 3.

[0101] Table 3

[0102]

[0103]

[0104] As can be seen from the test data in Table 3, the polybutylene terephthalate resin composition provided by the present invention has high whiteness, excellent mechanical properties, and good aging resistance.

[0105] In Example 9, after adjusting the feeding sequence, the number-average molecular weight of the bio-based PBT resin decreased, resulting in an increase in the melt index. The mechanical properties and aging resistance of the polybutylene terephthalate resin composition deteriorated, but its overall performance was still better than that of the polybutylene terephthalate resin composition provided in the comparative example.

[0106] The titanium content in the polybutylene terephthalate (PBT) resin composition provided in Comparative Example 1 is too low, which prolongs the polymerization time, reduces the number-average molecular weight of the bio-based PBT resin, and thus increases the melt index. This results in an increase in the b-value and a decrease in the L-value of the PBT resin composition, leading to poorer mechanical properties and aging resistance. The titanium content in the PBT resin composition provided in Comparative Example 2 is too high, resulting in a more vigorous polymerization reaction and more residual titanium, which will subsequently catalyze polymer degradation, further worsening the aging resistance of the PBT resin composition. The phosphorus content in the PBT resin composition provided in Comparative Example 3 is too low, leading to poor polymerization stability, a deterioration in the color value of the PBT resin composition, and deterioration in mechanical properties. The phosphorus content in the PBT resin composition provided in Comparative Example 4 is too high, affecting the polymerization rate, increasing the acid value of the PBT resin composition, and worsening its aging resistance. The cobalt content in the polybutylene terephthalate (PET) resin composition provided in Comparative Example 5 was too low, failing to achieve a color-correcting effect. This resulted in an increase in the b-value and a decrease in the l-value of the PET resin composition, leading to a deterioration in both mechanical properties and aging resistance. The cobalt content in the PET resin composition provided in Comparative Example 6 was too high, affecting the polymerization rate and consequently the acid value of the PET resin composition, thus worsening its mechanical properties, especially its aging resistance.

[0107] The mass ratios of titanium, phosphorus, and cobalt in the polybutylene terephthalate resin compositions provided in Comparative Examples 7 and 8 do not meet the specific range, which will cause the mechanical properties and aging resistance of the polybutylene terephthalate resin compositions to deteriorate.

[0108] The polybutylene terephthalate resin compositions provided in Comparative Examples 9-11 do not contain phosphorus and / or cobalt, which makes it impossible to maintain the whiteness, mechanical properties, and aging resistance of the polybutylene terephthalate resin compositions at a good level. In addition, the phosphorus content in Comparative Example 9, the cobalt content in Comparative Example 10, and the content of both phosphorus and cobalt in Comparative Example 11 are not 0, but about 0.1 ppm, which may be due to contamination of the polybutylene terephthalate resin compositions by the synthesis equipment during the preparation process.

[0109] The applicant declares that this invention illustrates the polybutylene terephthalate resin composition, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection and disclosure scope of this invention.

Claims

1. A polybutylene terephthalate resin composition, characterized in that, The polybutylene terephthalate resin composition includes bio-based polybutylene terephthalate resin, titanium, phosphorus, and cobalt. The phosphorus element comes from added phosphorus-containing compounds and / or non-added phosphorus-containing compounds; The non-added phosphorus-containing compounds include phosphorus-containing impurities in the raw materials; The added phosphorus-containing compound includes any one or a combination of at least two of phosphoric acid, phosphorous acid, hypophosphite, phosphate, alkyl phosphate, or triphenyl phosphate. The cobalt element is derived from added cobalt-containing compounds and / or non-added cobalt-containing compounds; The non-added cobalt-containing compounds include cobalt-containing impurities in the raw materials; The added cobalt-containing compound includes any one or a combination of two of cobalt oxides or organocobalt. The cobalt oxide includes cobalt trioxide and / or cobalt pentoxide; The organic cobalt includes any one or a combination of at least two of cobalt acetate, cobalt glycolate, or cobalt triacetate. The polybutylene terephthalate resin composition contains 20-150 ppm of titanium by weight, 2-45 ppm of phosphorus by weight, and 6-100 ppm of cobalt by weight. The mass ratio of titanium, phosphorus and cobalt in the polybutylene terephthalate resin composition is (2-20):(1-2):(1-10). The weight contents of titanium, phosphorus and cobalt in the polybutylene terephthalate resin composition were determined by ICP-OES analysis according to USEPA method 3052:1996, following the procedure below: 0.1 g of the polybutylene terephthalate resin composition was weighed, pulverized, and 5 mL of nitric acid was added to completely submerge the polybutylene terephthalate resin composition. Then, 1.0 mL of hydrogen peroxide was added dropwise and reacted for 2 min. The mixture was then sealed in a microwave digestion vessel and digested at 210 °C for 3 h. After cooling to room temperature, the mixture was filtered through a 0.45 μm filter membrane and diluted with distilled water to 50 mL. The final result was obtained by ICP-OES analysis.

2. The polybutylene terephthalate resin composition according to claim 1, characterized in that, The mass ratio of titanium, phosphorus and cobalt in the polybutylene terephthalate resin composition is (3-15):(1.1-1.5):(1-8).

3. The polybutylene terephthalate resin composition according to claim 2, characterized in that, The mass ratio of titanium, phosphorus and cobalt in the polybutylene terephthalate resin composition is (4-10):(1.2-1.4):(2-6).

4. The polybutylene terephthalate resin composition according to claim 1, characterized in that, The titanium content in the polybutylene terephthalate resin composition is 30-100 ppm by weight.

5. The polybutylene terephthalate resin composition according to claim 1, characterized in that, The phosphorus content in the polybutylene terephthalate resin composition is 5-30 ppm by weight.

6. The polybutylene terephthalate resin composition according to claim 1, characterized in that, The cobalt content in the polybutylene terephthalate resin composition is 10-80 ppm by weight.

7. The polybutylene terephthalate resin composition according to claim 1, characterized in that, Under conditions of 250℃ and 2.16kg weight, the melt index of the polybutylene terephthalate resin composition is ≤70g / 10min.

8. The polybutylene terephthalate resin composition according to claim 7, characterized in that, Under conditions of 250°C and 2.16 kg weight, the melt index of the polybutylene terephthalate resin composition is 10-69 g / 10 min.

9. The polybutylene terephthalate resin composition according to claim 8, characterized in that, Under conditions of 250℃ and 2.16kg weight, the melt index of the polybutylene terephthalate resin composition is 20-60g / 10min.

10. The polybutylene terephthalate resin composition according to claim 1, characterized in that, The number-average molecular weight of the bio-based polybutylene terephthalate resin is 20,000-50,000 g / mol.

11. The polybutylene terephthalate resin composition according to claim 10, characterized in that, The number average molecular weight of the bio-based polybutylene terephthalate resin is 20,000-45,000 g / mol.

12. The polybutylene terephthalate resin composition according to claim 1, characterized in that, The polybutylene terephthalate resin composition has an L value ≥ 88.0 and a b value ≤ 3.

0.

13. The polybutylene terephthalate resin composition according to claim 1, characterized in that, The tensile strength of the polybutylene terephthalate resin composition is ≥58MPa.

14. The polybutylene terephthalate resin composition according to claim 13, characterized in that, The tensile strength of the polybutylene terephthalate resin composition is 58.5-61 MPa.

15. The polybutylene terephthalate resin composition according to claim 1, characterized in that, The alkyl phosphate ester includes any one or a combination of at least two of triethyl phosphate, trimethyl phosphate, tributyl phosphate, trioctyl phosphate, or trihexyl phosphate.

16. A method for preparing a polybutylene terephthalate resin composition according to any one of claims 1-15, characterized in that, The preparation method includes the following steps: (1) Terephthalic acid, 1,4-butanediol and titanium-containing compound are reacted to obtain a first mixture; at least one of the terephthalic acid and 1,4-butanediol is a bio-based material; (2) The first mixture, the phosphorus-containing compound, and the cobalt-containing compound react to obtain a second mixture; (3) The second mixture is reacted to obtain the polybutylene terephthalate resin composition.

17. The preparation method according to claim 16, characterized in that, The general formula of the titanium-containing compound is Ti(OR)4; R is selected from at least one of C1-C10 straight-chain or branched alkyl groups and C6-C10 aryl groups.

18. The preparation method according to claim 17, characterized in that, The titanium-containing compounds include tetrabutyl titanate and / or isopropyl titanate.

19. The preparation method according to claim 16, characterized in that, The pressure of the reaction in step (1) is 30-100 kPa.

20. The preparation method according to claim 16, characterized in that, The reaction temperature in step (1) is 180-250℃.

21. The preparation method according to claim 16, characterized in that, The reaction time in step (1) is 1-5 hours.

22. The preparation method according to claim 16, characterized in that, The 1,4-butanediol is a bio-based 1,4-butanediol.

23. The preparation method according to claim 16, characterized in that, The reaction described in step (2) is carried out under a nitrogen atmosphere.

24. The preparation method according to claim 16, characterized in that, The reaction temperature in step (2) is 180-250℃.

25. The preparation method according to claim 16, characterized in that, The reaction time in step (2) is 10-30 min.

26. The preparation method according to claim 16, characterized in that, The reaction temperature in step (3) is 230-260℃.

27. The preparation method according to claim 16, characterized in that, The reaction time in step (3) is 3-6 hours.

28. The preparation method according to claim 16, characterized in that, The pressure of the reaction in step (3) is <200 Pa.

29. The preparation method according to claim 16, characterized in that, After the reaction in step (3) is completed, a granulation step is also included.

30. The use of a polybutylene terephthalate resin composition as described in any one of claims 1-15 in electronic appliances, new energy equipment or intelligent equipment.

31. The use of a polybutylene terephthalate resin composition as described in any one of claims 1-15 in household appliances, relays or communication connectors.

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