Polybutylene terephthalate resin composition as well as preparation method and application thereof

Abstract

The invention relates to a polybutylene terephthalate resin composition as well as a preparation method and application thereof. The polybutylene terephthalate resin composition comprises bio-based polybutylene terephthalate resin, a titanium element, a phosphorus element and a cobalt element, the weight content of a titanium element in the polybutylene terephthalate resin composition is 20 to 150 ppm, the weight content of a phosphorus element is 2 to 50 ppm, and the weight content of a cobalt element is 4 to 100 ppm; the mass ratio of the titanium element to the phosphorus element to the cobalt element in the polybutylene terephthalate resin composition is (2-20): (1-2): (1-10). According to the polybutylene terephthalate resin composition provided by the invention, the weight content and the mass ratio of the titanium element, the phosphorus element and the cobalt element are controlled in a proper range, so that the polybutylene terephthalate resin composition has high whiteness, excellent mechanical property and ageing resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of bio-based plastics, and specifically relates to a polybutylene terephthalate resin composition and a preparation method and application thereof. Background Art

[0002] As a typical engineering plastic, polybutylene terephthalate (PBT) has good mechanical properties, electrical properties, heat resistance and processing properties, and is widely used in electronics, automobiles, machinery, household appliances and other industries. Traditional PBT is prepared using petroleum-based raw materials. However, facing the serious situation of the continuous depletion of fossil resources and the increasing environmental pollution, it is an inevitable trend to turn to environmentally friendly and process-efficient renewable biological resources as raw materials.

[0003] Bio-based materials refer to biomass synthetic materials, biomass renewable materials and basic chemical raw materials obtained through biosynthesis, bioprocessing and biorefining processes using renewable resources as raw materials. Bio-based materials are currently mainly used to produce plastics, fibers, nylon and rubber, etc., and have the characteristics of renewable raw materials, biodegradability, and less harmful substances generated during the processing and production process. Bio-based materials are the focus of the development of modern biomanufacturing industry and a major industrial direction for green growth of social economy. The large-scale development of bio-based materials will reduce the dependence of the chemical materials industry on fossil resources, which is conducive to environmental improvement and coordinated economic development. It is of great significance to accelerate the cultivation of strategic emerging industries, promote the transformation and upgrading of my country's petrochemical materials, promote green economic growth, and promote agricultural-industrial integration and urbanization.

[0004] At present, the use of bio-based materials instead of petroleum-based materials to prepare bio-based PBT resins has received more and more attention. However, impurities in bio-based materials will affect the color value of bio-based PBT resins, making the whiteness of bio-based PBT resins low and easy to turn yellow, affecting the use of bio-based PBT resins. Therefore, it is urgent 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 deficiencies in the prior art, the object of the present invention is to provide a polybutylene terephthalate resin composition, a preparation method and application thereof. By controlling the weight content and mass ratio of titanium, phosphorus and cobalt 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 object, the present invention adopts the following technical solutions:

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

[0008] In the present invention, the titanium element in the polybutylene terephthalate resin composition can catalyze the synthesis of the PBT resin composition, the phosphorus element can play the role of a stabilizer, and the cobalt element can play a catalytic role and also play a role in adjusting the whiteness of the PBT resin composition; if the content of the titanium element is too low, the molecular weight of the synthesized bio-based PBT resin is low and the performance is poor; if the content of the titanium element is too high, the aging resistance of the PBT resin composition will be affected; if the content of the phosphorus element is too low, it will not play the role of a stabilizer, and if the content of the phosphorus element is too high, the acid value of the PBT resin composition will increase, thereby affecting its aging resistance; if the content of the cobalt element is too low, the color of the PBT resin composition tends to be yellowish; if the content of the cobalt element is too high, the aging resistance of the PBT resin composition will be affected; the mass ratio of the titanium element, the phosphorus element and the cobalt element in the polybutylene terephthalate resin composition needs to be controlled within an appropriate range, and exceeding the limited range will affect the acid value, whiteness, mechanical properties and aging resistance of the PBT resin composition.

[0009] In the present invention, the weight contents of titanium, phosphorus and cobalt in the polybutylene terephthalate resin composition are measured by ICP-OES analysis with reference to US EPA method 3052:1996, according to the following procedure: 0.1 g of the polybutylene terephthalate resin composition is weighed, crushed, and then 5 mL of nitric acid is added to completely immerse the polybutylene terephthalate resin composition, then 1.0 mL of hydrogen peroxide is dropped into it for reaction for 2 minutes, sealed in a microwave digestion tank and digested at 210° C. for 3 hours, cooled to room temperature, filtered with a 0.45 μm filter membrane, and diluted to 50 mL with distilled water, and tested by ICP-OES (Spectro arcos FHS12 inductively coupled plasma emission spectrometer, AMETEK, USA).

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

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

[0012] The weight content of the phosphorus element is 2-50 ppm, 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 4-100ppm, for example, it can be 4ppm, 10ppm, 15ppm, 20ppm, 25ppm, 30ppm, 35ppm, 40ppm, 45ppm, 50ppm, 55ppm, 60ppm, 65ppm, 70ppm, 75ppm, 80ppm, 85ppm, 90ppm, 95ppm, 100ppm.

[0014] The mass ratio of titanium element, phosphorus element and cobalt element 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] The present invention does not particularly limit the source of phosphorus in the polybutylene terephthalate resin composition, which may come from an added phosphorus-containing compound, or from a non-added phosphorus-containing compound such as phosphorus-containing impurities in the raw material, or a combination of the two. In addition, the production processes of raw materials (such as raw materials for preparing bio-based polybutylene terephthalate resin) from different manufacturers are different, and the raw materials may be contaminated during storage, transportation, transfer, and production and processing, so that the content of phosphorus in the polybutylene terephthalate resin composition finally obtained is different.

[0016] The present invention does not impose any particular restrictions on the source of the titanium element in the polybutylene terephthalate resin composition, which may come from an added titanium-containing compound, or from a non-added titanium-containing compound such as titanium-containing impurities in the raw material, or a combination of the two. In addition, the production processes of raw materials (such as raw materials for preparing bio-based polybutylene terephthalate resin) from different manufacturers are different, and the raw materials may be contaminated during storage, transportation, transfer, and production and processing, so that the content of titanium element in the final polybutylene terephthalate resin composition is different.

[0017] The present invention does not particularly limit the source of the cobalt element in the polybutylene terephthalate resin composition, which may come from an added cobalt-containing compound, or from a non-added cobalt-containing compound such as cobalt-containing impurities in the raw material, or a combination of the two. In addition, the production processes of raw materials (such as raw materials for preparing bio-based polybutylene terephthalate resin) from different manufacturers are different, and the raw materials may be contaminated during storage, transportation, transfer, and production and processing, so that the content of cobalt in the polybutylene terephthalate resin composition finally obtained is different.

[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. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[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 mass ratio of titanium, phosphorus and cobalt in the polybutylene terephthalate resin composition is further preferably (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 weight content of titanium element in the polybutylene terephthalate resin composition is 30-100 ppm, 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 weight content of phosphorus in the polybutylene terephthalate resin composition is 5-30 ppm, for example, it can be 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 weight content of cobalt element in the polybutylene terephthalate resin composition is 10-80 ppm, for example, it can be 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 ISO1133 standard, at 250°C and 2.16 kg weight, the melt index of the polybutylene terephthalate resin composition is ≤70g / 10min, for example, it can be 2g / 10min, 4g / 10min, 6g / 10min, 8g / 10min, 10g / 10min, 12g / 10min, 14g / 10min, 16g / 10min, 20g / 10min, 25g / 10min, 30g / 10min, 35g / 10min, 40g / 10min, 45g / 10min, 50g / 10min, 55g / 10min, 60g / 10min, 65g / 10min, 70g / 10min, etc.

[0025] Preferably, according to ISO1133 standard, at 250° C. and 2.16 kg weight, the melt index of the polybutylene terephthalate resin composition is 10-69 g / 10 min (for example, 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, 67 g / 10 min, 68 g / 10 min, 70 g / 10 min, 71 g / 10 min, 72 g / 10 min, 73 g / 10 min, 74 g / 10 min, 76 g / 10 min, 77 g / 10 min, 78 g / 10 min, 79 g / 10 min, 80 g / 10 min, 81 g / 10 min, 82 g / 10 min, 83 g / 10 min, 84 g / 10 min, 86 g / 10 min, 87 g / 10 min, 88 g / 10 min, 89 g / 10 min, 90 g / 10 min, 91 g / 10 min, 92 g / 10 min, 93 g / 10 min, 94 g / 10 min, 95 g / 10 min, 96 g / 10 min, 97 g / 10 min, 98 g / 10 min, 99 g / 10 min, 100 g / 10 7g / 10min, 68g / 10min, etc.), and further preferably is 20-60g / 10min (for example, 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, 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] Further preferably, the number average molecular weight of the bio-based polybutylene terephthalate resin is 20000-45000 g / mol, for example, it can be 21000 g / mol, 23000 g / mol, 25000 g / mol, 27000 g / mol, 29000 g / mol, 31000 g / mol, 33000 g / mol, 35000 g / mol, 37000 g / mol, 39000 g / mol, 41000 g / mol, 43000 g / mol, 45000 g / mol, etc.

[0028] Preferably, the L value of the polybutylene terephthalate resin composition is ≥88.0 (for example, 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.) , b value ≤ 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 ≥58 MPa, for example, it may be 58 MPa, 58.5 MPa, 59 MPa, 59.5 MPa, 60 MPa, 60.5 MPa, 61 MPa, 61.5 MPa, 62 MPa, 62.5 MPa, 63 MPa, etc.

[0030] Preferably, the flexural modulus of the polybutylene terephthalate resin composition is 58.5-61 MPa, for example, it may 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 the polybutylene terephthalate resin composition as described in the first aspect, the preparation method comprising the following steps:

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

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

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

[0035] In the present invention, the bio-based materials refer to biomass synthetic materials, biomass renewable materials and basic chemical raw materials obtained from renewable resources such as starch, cellulose and other raw materials through bio-fermentation, biosynthesis, bioprocessing and biorefining 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 as 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 as 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 of phosphoric acid, phosphorous acid, hypophosphorous acid, phosphates, alkyl phosphates or triphenyl phosphate, or a combination of at least two thereof.

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

[0042] Preferably, the cobalt-containing compound comprises any one of an inorganic cobalt salt, a cobalt oxide or an organic cobalt, or a combination of at least two thereof.

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

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

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

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

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

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

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

[0050] The C6-C10 aryl group illustratively includes, but is not limited to, phenyl or naphthyl.

[0051] Preferably, the titanium-containing compound comprises n-butyl 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°C, for example, 180°C, 182°C, 185°C, 188°C, 190°C, 192°C, 195°C, 198°C, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C, etc.

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

[0055] Preferably, the 1,4-butanediol is 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°C, for example, 180°C, 182°C, 185°C, 188°C, 190°C, 192°C, 195°C, 198°C, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C, etc.

[0058] Preferably, the reaction time of 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°C, for example, it may be 230°C, 232°C, 234°C, 236°C, 238°C, 240°C, 242°C, 244°C, 246°C, 248°C, 250°C, 252°C, 254°C, 256°C, 258°C, 260°C, etc.

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

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

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

[0063] In a third aspect, the present invention provides a use 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 the invention has high whiteness, is not easy to yellow, has a b value of 1.0-2.9, an L value of 88.1-89.8, and has excellent mechanical properties and aging resistance, wherein the tensile strength can reach 58.6-60.6MPa, and the retention rate of the tensile strength after aging treatment can reach 90.0-92.8%. DETAILED DESCRIPTION

[0066] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

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

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

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

[0070] (3) n-Butyl titanate: purchased from Tianjin Komiou Reagent, purity ≥ 99.0%;

[0071] (4) Isopropyl titanate: purchased from Tianjin Komiou 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 the amounts thereof are shown in Table 1; the preparation method of the polybutylene terephthalate resin composition comprises the following steps:

[0078] (1) mixing terephthalic acid, bio-based 1,4-butanediol and a titanium-containing compound, and maintaining the mixture at a pressure of 40 kPa and a temperature of 230° C. for 1.5 hours to obtain a first mixture;

[0079] (2) introducing nitrogen into the first mixture, adding a phosphorus-containing compound and a cobalt-containing compound, and maintaining the mixture for 20 minutes to obtain a second mixture;

[0080] (3) The pressure of the second mixture is reduced to 100 Pa, and the mixture is heated to 250° C. and maintained for 4.5 hours. The mixture is filled with nitrogen and granulated 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 specifically shown in Tables 1 and 2, wherein "-" represents that the substance is not used; the preparation methods of the polybutylene terephthalate resin compositions provided in Examples 2-8 and Comparative Examples 1-11 refer to Example 1;

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

[0085] (1) mixing terephthalic acid, bio-based 1,4-butanediol and cobalt acetate, and maintaining the mixture at a pressure of 40 kPa and a temperature of 230° C. for 1.5 hours to obtain a first mixture;

[0086] (2) nitrogen was introduced into the first mixture, and triphenyl phosphate and n-butyl titanate were added, and the mixture was kept for 20 minutes to obtain a second mixture;

[0087] (3) The pressure of the second mixture is reduced to 100 Pa, and the mixture is heated to 250° C. and maintained for 4.5 hours. The mixture is filled with nitrogen and granulated 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 the polybutylene terephthalate resin composition: Referring to US EPA method 3052:1996, ICP-OES analysis was performed according to the following procedure: 0.1 g of the polybutylene terephthalate resin composition was weighed, crushed, and 5 mL of nitric acid was added to completely immerse the polybutylene terephthalate resin composition, and then 1.0 mL of hydrogen peroxide was dropped into the mixture for reaction for 2 min. The mixture was sealed in a microwave digestion tank and digested at 210° C. for 3 h. After cooling to room temperature, the mixture was filtered using a 0.45 μm filter membrane and diluted to 50 mL using distilled water. The mixture was tested using ICP-OES (Spectro arcos FHS12 inductively coupled plasma emission spectrometer, AMETEK, USA);

[0095] (2) Melt index: measured using a melt indexer (zwick C-FLOW) according to ISO1133 at 250°C and 2.16 kg weight, unit: g / 10 min;

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

[0097] (4) Whiteness: 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 three-dimensional space (chromaticity, brightness and saturation) to two-dimensional space (Lab value), thereby achieving a unified description of color. According to the standard CIE 1976 (L*a*b*), a colorimeter (Weifu Optoelectronics WF-30) is used to test and obtain the b value and L value.

[0098] (5) Tensile strength: According to ISO 178-2010, 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: The parallel tensile strength specimens were aged at 85°C and 85% RH for 1000 h, and then the tensile strength of the aging specimens was tested using a tensile testing machine (zwick ProLine). 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. The test results are shown in Table 3:

[0101] Table 3

[0102]

[0103]

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

[0105] After adjusting the addition order in Example 9, the number average molecular weight of the bio-based PBT resin decreased, thereby increasing the melt index, and the mechanical properties and aging resistance of the polybutylene terephthalate resin composition deteriorated, but its comprehensive performance was still better than that of the polybutylene terephthalate resin composition provided in the comparative example.

[0106] The content of titanium in the polybutylene terephthalate resin composition provided in Comparative Example 1 is too low, the polymerization time will be extended, the number average molecular weight of the bio-based PBT resin will be reduced, so that the melt index will increase, the b value of the polybutylene terephthalate resin composition will increase, the L value will decrease, and the mechanical properties and aging resistance will deteriorate. The content of titanium in the polybutylene terephthalate resin composition provided in Comparative Example 2 is too high, the polymerization reaction is more intense, and the residual titanium is more, which will subsequently catalyze the degradation of the polymer, so that the aging resistance of the polybutylene terephthalate resin composition will deteriorate. The content of phosphorus in the polybutylene terephthalate resin composition provided in Comparative Example 3 is too low, the polymerization stability deteriorates, the color value of the polybutylene terephthalate resin composition deteriorates, and the mechanical properties deteriorate. The content of phosphorus in the polybutylene terephthalate resin composition provided in Comparative Example 4 is too high, which affects the polymerization reaction rate, the acid value index of the polybutylene terephthalate resin composition becomes higher, and the aging resistance deteriorates. The content of cobalt in the polybutylene terephthalate resin composition provided in Comparative Example 5 is too low, and the toning effect is not achieved, so that the b value of the polybutylene terephthalate resin composition increases, the L value decreases, and the mechanical properties and aging resistance of the polybutylene terephthalate resin composition deteriorate. The content of cobalt in the polybutylene terephthalate resin composition provided in Comparative Example 6 is too high, which affects the polymerization reaction rate, and further affects the acid value index of the polybutylene terephthalate resin composition, so that its mechanical properties deteriorate, especially the aging resistance deteriorates significantly.

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

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

[0109] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the polybutylene terephthalate resin composition of the present invention and its preparation method and application, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A polybutylene terephthalate resin composition, characterized in that: The polybutylene terephthalate resin composition includes bio-based polybutylene terephthalate resin, titanium element, phosphorus element and cobalt element; The polybutylene terephthalate resin composition contains 20-150 ppm titanium, 2-50 ppm phosphorus and 4-100 ppm cobalt. The mass ratio of titanium element, phosphorus element and cobalt element in the polybutylene terephthalate resin composition is (2-20):(1-2):(1-10).

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), and more preferably (4-10):(1.2-1.4):(2-6); Preferably, the weight content of titanium in the polybutylene terephthalate resin composition is 30-100 ppm; Preferably, the weight content of phosphorus in the polybutylene terephthalate resin composition is 5-30 ppm; Preferably, the weight content of cobalt element in the polybutylene terephthalate resin composition is 10-80 ppm.

3. The polybutylene terephthalate resin composition according to claim 1, characterized in that 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; Preferably, under the conditions of 250° C. and 2.16 kg weight, the melt index of the polybutylene terephthalate resin composition is 10-69 g / 10 min, more preferably 20-60 g / 10 min; Preferably, the number average molecular weight of the bio-based polybutylene terephthalate resin is 20,000-50,000 g / mol, more preferably 20,000-45,000 g / mol.

4. The polybutylene terephthalate resin composition according to claim 1, characterized in that The polybutylene terephthalate resin composition has an L value of ≥88.0 and a b value of ≤3.0; Preferably, the tensile strength of the polybutylene terephthalate resin composition is ≥58 MPa; Preferably, the polybutylene terephthalate resin composition has a tensile strength of 58.5-61 MPa.

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

6. The preparation method according to claim 5, characterized in that: The phosphorus-containing compound includes any one or a combination of at least two of phosphoric acid, phosphorous acid, hypophosphorous acid, phosphate, alkyl phosphate or triphenyl phosphate; Preferably, the alkyl phosphate includes any one of triethyl phosphate, trimethyl phosphate, tributyl phosphate, trioctyl phosphate or trihexyl phosphate, or a combination of at least two thereof.

7. The preparation method according to claim 5, characterized in that: The cobalt-containing compound includes any one of an inorganic cobalt salt, a cobalt oxide or an organic cobalt, or a combination of at least two thereof; Preferably, the inorganic cobalt salt comprises any one or a combination of at least two of cobalt chloride, cobalt sulfate or cobalt bromide; Preferably, the cobalt oxide comprises cobalt trioxide and / or cobalt pentoxide; Preferably, the organic cobalt includes any one of cobalt acetate, cobalt glycol or cobalt triacetate, or a combination of at least two thereof.

8. The preparation method according to claim 5, characterized in that: The general formula of the titanium-containing compound is Ti(OR)4; Wherein, R is selected from at least one of C1-C10 straight or branched alkyl and C6-C10 aryl; Preferably, the titanium-containing compound comprises n-butyl titanate and / or isopropyl titanate.

9. The preparation method according to claim 5, characterized in that: The reaction pressure in step (1) is 30-100 kPa; Preferably, the reaction temperature in step (1) is 180-250°C; Preferably, the reaction time in step (1) is 1-5h; Preferably, the 1,4-butanediol is bio-based 1,4-butanediol; Preferably, the reaction in step (2) is carried out under a nitrogen atmosphere; Preferably, the reaction temperature in step (2) is 180-250°C; Preferably, the reaction time in step (2) is 10-30 min; Preferably, the reaction temperature in step (3) is 230-260°C; Preferably, the reaction time in step (3) is 3-6 hours; Preferably, the pressure of the reaction in step (3) is less than 200 Pa; Preferably, after the reaction in step (3) is completed, a granulation step is also included.

10. Use of the polybutylene terephthalate resin composition according to any one of claims 1 to 4 in electronic appliances, household appliances, new energy equipment, intelligent equipment, relays or communication connectors.

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