An anti-lodging PBT / PA12 sharpened toothbrush filament and its preparation method

Abstract

The present invention discloses an anti-collapse PBT / PA12 sharpened toothbrush filament and its preparation method. The raw materials contain the following components by weight: 60-90 parts of polybutylene terephthalate (PBT), 10-40 parts of nylon 12 (PA12), 1-5 parts of amphiphilic block copolymer, 0.1-0.5 parts of antioxidant, and 0.1-0.5 parts of lubricant. The amphiphilic block copolymer used in the present invention is a block copolymer formed by the amidation reaction of a dicarboxyl-terminated polybutylene terephthalate oligomer and a diamino-terminated nylon 12 oligomer. This amphiphilic block copolymer can effectively improve the compatibility of PBT and PA12, and achieve the submicron-sized dispersion of the PA12 dispersed phase in the PBT matrix. A kind of anti-collapse PBT / PA12 sharpened toothbrush filament is prepared by melt spinning and filament cake sharpening of the blend.

Description

Technical Field

[0001] The present invention relates to the field of brush filaments, and particularly to an anti-collapse PBT / PA12 sharpened toothbrush filament. Background Art

[0002] Toothbrushes are indispensable brushing tools in people's daily lives. The quality of a toothbrush mainly depends on the quality of the brush filaments. Currently, the main types of toothbrush filaments are polyester filaments and nylon filaments. Polyester filaments are mainly PBT filaments. Compared with nylon filaments, the greatest advantage of PBT filaments is that they can be chemically sharpened (using NaOH solution as the chemical sharpening liquid). After sharpening, the head fibers of the polyester filaments are conical. When made into a toothbrush, the head is relatively soft, causing less damage to the gums and can penetrate into the tooth gaps, having a better cleaning effect compared to flat-headed toothbrush filaments. However, the poor anti-collapse performance of polyester filaments restricts their further promotion. Nylon toothbrush filaments have better flexibility and anti-collapse performance compared to PBT filaments. However, due to the excellent solvent resistance of nylon materials, traditional chemical sharpening methods (using NaOH solution as the chemical sharpening liquid) cannot be used for sharpening. Some manufacturers use mechanical sharpening methods to prepare nylon sharpened filaments, but the cost is high, the efficiency is low, and the product appearance cannot meet the needs of consumers. Therefore, preparing an anti-collapse and sharpenable toothbrush filament has always been the goal pursued by researchers.

[0003] Blending modification is a commonly used method to balance the properties of polymer materials. Blending nylon materials with excellent anti-collapse performance with PBT to prepare toothbrush filaments is expected to improve the anti-collapse performance of PBT brush filaments while retaining their advantage of being chemically sharpenable. However, nylon and PBT are two thermodynamically incompatible polymers. Under conventional blending methods, the nylon dispersed phase will be dispersed in the PBT matrix with a size of several micrometers or even dozens of micrometers. The large-sized nylon dispersed phase will become stress defect points, leading to the deterioration of the properties of the blend. Only when the nylon dispersed phase is dispersed in a submicron (0.1 - 1 μm) size can the properties of the blend be optimized.

[0004] Nylon 12 is a long-chain nylon material prepared by ring-opening polymerization of dodecanolactam. Compared with nylon 610 and nylon 612, it has excellent flexibility, low water absorption rate, and comparable anti-collapse performance, and can be applied to the modification of PBT to prepare anti-collapse sharpened filaments.

[0005] Patent CN101724257A uses a hyperbranched polyethyleneimine-grafted nylon as a solubilizer to prepare a nylon-polyester blend. The numerous terminal amino groups of polyethyleneimine react with the carboxyl groups in nylon and polyester in solution to obtain a ternary copolymer of polyethyleneimine-co-nylon-co-polyester. Its drawback is that the three components need to be first formulated into a solution with a solvent, and an amidation reaction occurs at high temperature. The numerous terminal amino groups of hyperbranched polyethyleneimine are prone to cross-linking reactions during the amidation reaction, and it is difficult to control the reaction end point. The resulting ternary copolymer contains a large number of amide groups, which will lead to poor water resistance and chemical resistance.

[0006] Patent CN102660019B prepares a high-temperature-resistant nylon / PBT / PET copolymer by solution polymerization. PBT, PET, and an aliphatic diamine are added together to a solvent to carry out a copolymerization reaction. Its reaction requires a relatively high temperature and the solvent cannot be recovered, making it difficult to achieve industrial promotion.

[0007] Patent CN113773508B uses a sulfonic acid group-grafted modified polyester as a solubilizer. The sulfonic acid group undergoes a chemical reaction with the amide group of nylon to obtain an internal compatibilizing segment, solving the compatibility problem of polyester / nylon composites. The problem with this method is that the acquisition of the sulfonic acid group-grafted modified polyester and the reaction degree of the reaction between the sulfonic acid group and the amide group in the screw cannot be controlled. Summary of the Invention

[0008] The object of the present invention is to prepare an anti-lodging PBT / PA12 sharpened toothbrush filament.

[0009] The main technical problem faced by the present invention is to achieve submicron-sized dispersion of nylon 12 dispersed phase in the PBT matrix.

[0010] To solve the above technical problems, the technical principle adopted by the present invention is: utilizing the principle of "like dissolves like", polymers with similar chemical structures have good compatibility. The main technical problem of the present invention is transformed into preparing a polymer with a structure similar to that of nylon 12 and PBT, and this polymer has good compatibility with both nylon 12 and PBT. Using the amidation reaction mechanism, a PBT oligomer capped with double carboxyl groups and a nylon 12 oligomer capped with double amino groups are subjected to an amidation reaction to prepare a PBT-nylon 12 block copolymer. This block copolymer can effectively improve the compatibility between PBT and nylon 12, and is expected to disperse nylon 12 in the PBT matrix in submicron size to improve the anti-lodging performance. In addition, by controlling the blending ratio of PBT and nylon 12, nylon 12 is dispersed in the "sea phase" PBT in the form of "island phase", which will not change the chemically sharpenable performance of the blend for preparing toothbrush filaments, thereby preparing an anti-lodging PBT / PA12 sharpened toothbrush filament.

[0011] Therefore, to achieve the above object, the technical solution adopted by the present invention is as follows:

[0012] An anti-lodging PBT / PA12 sharpened toothbrush filament, by weight, the raw materials comprise the following components:

[0013]

[0014] In some examples, preferably, the relative viscosity of the PBT is 0.6 - 0.85 (using phenol - 1,1,2,2 - tetrachloroethane = 1:1 (w / w) as the solvent, at a concentration of 0.005 g / ml), more preferably 0.75.

[0015] In some examples, preferably, the relative viscosity of the nylon 12 is 1.60 - 1.90 (using m - cresol as the solvent, at a concentration of 0.005 g / ml), more preferably 1.80.

[0016] In some examples, the antioxidant is selected from heat - resistant antioxidants, and is one or more of antioxidant 1010, antioxidant 1098, antioxidant 168, antioxidant H10, preferably the 1:1 equal - mass compounding system of antioxidant 1010 and antioxidant 168.

[0017] In some examples, the lubricant is selected from one or more of ethylene bisstearamide (EBS), oleic acid amide, silicone oil, paraffin wax, preferably ethylene bisstearamide (EBS).

[0018] In some examples, the amphiphilic block copolymer is a block copolymer formed by the amidation reaction of a double - carboxyl - terminated PBT oligomer and a double - amino - terminated nylon 12 oligomer, and its preparation method comprises the following steps:

[0019] (1) Preparation of double - carboxyl - terminated PBT oligomer:

[0020] (1 - 1) Under an inert gas atmosphere, terephthalic acid (PTA), 1,4 - butanediol (BDO) and catalyst 1 are maintained at 220 - 240 °C for 1 - 3 h for an esterification reaction; maintained at 220 - 240 °C, purged with nitrogen for 0.5 - 1 h for a prepolymerization reaction;

[0021] (1 - 2) After the prepolymerization is completed, catalyst 2 is added, and the reaction is carried out at 240 - 250 °C and an absolute pressure below 100 Pa for 0.5 - 2 h; stop vacuum pumping, supplement inert gas to 50 - 100 kPa, and cool the high - temperature melt by water cooling, dry, and pulverize to prepare the double - carboxyl - terminated PBT oligomer.

[0022] Preferably, catalyst 1 and catalyst 2 are independently selected from one or more of tetrabutyl titanate, tetraisopropyl titanate, dioctyltin oxide, preferably dioctyltin oxide.

[0023] Preferably, the addition amount of catalyst 1 is 0.5 - 2‰ of the mass of terephthalic acid.

[0024] Preferably, the addition amount of catalyst 2 is 1-3‰ of the mass of terephthalic acid.

[0025] Preferably, the number-average molecular weight of the prepared dicarboxyl-terminated PBT oligomer is 1000-3000, and the number-average molecular weight is regulated by the feed ratio of terephthalic acid and butanediol.

[0026] Preferably, the carboxyl end group content of the dicarboxyl-terminated PBT oligomer is 0.65-2.0 mmol / g.

[0027] (2) Preparation of diamino-terminated nylon 12 oligomer:

[0028] (2-1) Under an inert gas atmosphere, laurolactam, diamine-based capping agent and water are maintained at 270-290 °C for 3-7 h, preferably 5 h to complete the ring-opening reaction of laurolactam;

[0029] (2-2) After the ring-opening is completed, the pressure is released to atmospheric pressure, and the temperature is reduced to 180-220 °C while releasing the pressure, and then vacuum treatment is carried out for 30-60 min to complete melt polycondensation; after the melt polycondensation is completed, the vacuum pumping is stopped and protected by an inert gas.

[0030] Preferably, the number-average molecular weight of the prepared nylon 12 oligomer is 1000-3000.

[0031] Preferably, the diamine-based capping agent is one or more of hexanediamine, sebac diamine, and dodecane diamine, more preferably dodecane diamine, and the addition amount is determined by the number-average molecular weight of the nylon 12 oligomer.

[0032] Preferably, the addition amount of water is 8-18% of the mass of laurolactam, more preferably 12%.

[0033] Preferably, the amino end group content of the nylon 12 oligomer is 0.65-2.0 mmol / g.

[0034] (3) Preparation of amphiphilic block copolymer:

[0035] Under an inert gas atmosphere, the diamino-terminated nylon 12 oligomer, the dicarboxyl-terminated PBT oligomer and the molecular weight regulator are reacted at 240-250 °C and an absolute pressure below 1 kPa for 30-60 min to cause the dicarboxyl-terminated PBT oligomer and the diamino-terminated nylon 12 oligomer to undergo an amidation reaction to obtain a PBT and PA12 block copolymer, which is drawn, water-cooled, pelletized, and dried to obtain amphiphilic block copolymer pellets.

[0036] In the step (3), the ratio of the number of moles of carboxyl end groups of the dicarboxyl-terminated PBT oligomer to the number of moles of amino end groups of the diamino-terminated nylon 12 oligomer is 1:1.

[0037] The number-average molecular weight of the amphiphilic block copolymer is 10,000 - 30,000, preferably 20,000.

[0038] Preferably, the molecular weight regulator is selected from one of adipic acid, sebacic acid, dodecanedioic acid, benzoic acid, and lauric acid, preferably adipic acid, and the addition amount is determined by the number-average molecular weight of the amphiphilic block copolymer.

[0039] In some examples, the method for preparing the lodging-resistant PBT / PA12 sharpened toothbrush filaments of the present invention includes the following steps:

[0040] (a) Preparation step of PBT / PA12 blended pellets: Polybutylene terephthalate, nylon 12, amphiphilic block copolymer, lubricant, and antioxidant are added to a high-speed mixer and mixed for 10 - 20 min to obtain a blended material. Then, the blended material is melt-blended and extruded using a twin-screw extruder, water-cooled, pelletized, dried to prepare PBT / PA12 blended pellets;

[0041] (b) Cake preparation step: The cake is prepared using a melt spinning production line. The blended pellets prepared in step (a) are plasticized by a single-screw extruder, extruded through a spinneret, water-cooled and shaped, hot-stretched, wound on a roll, heat-treated and hardened, and packaged and cut to prepare the cake;

[0042] (c) Cake sharpening treatment step: The cake prepared in step (b) is placed in a cake sharpening tank filled with a sharpening liquid for sharpening treatment, washed, and dried to prepare sharpened toothbrush filaments.

[0043] In some examples, the aspect ratio of the twin-screw extruder used in step (a) is 40 - 45, the screw speed is 100 - 200 rpm, and the temperature is set from the feeding section to the head to 180 - 250 °C.

[0044] In some examples, in the PBT / PA12 blended pellets, PA12 is dispersed in the "sea phase" PBT matrix in the form of "island phase"; the size of the PA12 "island phase" dispersed phase is in the sub-micron range.

[0045] In some examples, the aspect ratio of the single-screw extruder used in step (b) is 25 - 30, the screw speed is 100 - 200 rpm, and the temperature is set from the feeding section to the head to 200 - 280 °C.

[0046] In some examples, in step (b), the hot stretching is carried out in a hot oven at 130 - 160 °C, preferably 140 °C; the stretching ratio is 3 - 6, preferably 4; the diameter of the monofilament after hot stretching is 6 - 8 mil, preferably 7 mil.

[0047] In some examples, in step (b), the tow is heat-treated and hardened in a nitrogen-filled oven. The temperature of the nitrogen-filled oven is 100 - 130 °C, preferably 120 °C, and the treatment time is 1 - 3 h, preferably 2 h.

[0048] In some examples, in step (b), the cut cake bundle has a diameter of 50 ± 2 mm and a height of 30 ± 2 mm.

[0049] In some examples, the sharpening liquid used in step (c) is an aqueous NaOH solution with a concentration of 30 - 50 wt%, preferably 40 wt%; the treatment temperature is 100 - 140 °C, preferably 120 °C; and the treatment time is 40 - 80 min, preferably 60 min.

[0050] In some examples, in step (c), after the cake is sharpened, it needs to be washed with clear water until it shows neutrality (pH = 7), and then dried in a vacuum oven at 80 - 100 °C for 10 - 12 h to obtain the finished sharpened toothbrush filaments.

[0051] Compared with the prior art, the advantages of the present invention mainly lie in: the present invention uses the amideification reaction mechanism to carry out an amideification reaction between a PBT oligomer capped with dicarboxyl groups and a nylon 12 oligomer capped with diamino groups to prepare a PBT / nylon 12 block copolymer. When using this block copolymer as a compatibilizer for melt blending of PBT and nylon 12, the block copolymer can effectively improve the compatibility between PBT and nylon 12, enabling nylon 12 to be dispersed in the PBT matrix in submicron size. The nylon 12 dispersed in submicron size can improve the anti-collapse performance of the PBT filaments. In addition, by controlling the blending ratio of PBT and nylon 12, the nylon 12 dispersed in the "island phase" in the "sea phase" PBT does not change the chemically sharpenable performance of the blend for preparing toothbrush filaments, thereby preparing an anti-collapse PBT / PA12 sharpened toothbrush filament. Description of the Drawings

[0052] Figure 1 SEM image of the PBT / PA12 blended granule prepared in Example 5.

[0053] Figure 2 Optical microscope image of the sharpened toothbrush filament prepared in Example 5. Detailed Description of the Invention

[0054] The present invention will be further described below through specific examples. The examples described in the present invention are only for the purpose of illustrating the present invention and do not limit the scope of the present invention.

[0055] Testing Method:

[0056] (1) Number-average molecular weight test: It is tested through a gel permeation chromatography (GPC) system, and the equipment model is WATERS1515;

[0057] (2) Tests for the contents of terminal carboxyl groups and terminal amino groups: Test by potentiometric titration method (Metrohm 848 automatic potentiometric titrator);

[0058] (3) Scanning electron microscopy (SEM) test of PBT / PA12 blended pellets: Snap the PBT / PA12 blended material bar in liquid nitrogen, etch the brittle fracture surface with 88% formic acid for 3 min, then sputter gold and observe the fracture surface with a scanning electron microscope (JSG-5900LV, Japan).

[0059] (4) Test for the anti-collapse performance of the brush filaments: Prepare the sharpened toothbrush filaments into a standard toothbrush, load a 335 g weight for testing, the testing speed is 13 mm / s, the testing time is 24 h, and judge the anti-collapse effect of the brush filaments according to the proportion of collapsed brush filaments. The evaluation criteria are: no collapse: 0 - 30%; slight collapse: 30 - 50%; collapse: 50 - 70%; obvious collapse: 70 - 90%; complete collapse: 100%

[0060]

Preparation Example 1

[0061] Prepare the amphiphilic block copolymer according to the following steps

[0062] a. Preparation of double carboxyl-terminated PBT oligomer: Add 2330 g of terephthalic acid (PTA), 1000 g of 1,4-butanediol (BDO) and 2.33 g of dioctyltin oxide into the reaction kettle, replace the nitrogen three times, heat up to 240 °C and keep it for 1 h for the esterification reaction. After the esterification reaction is completed, keep 240 °C, purge with nitrogen for 0.5 h for the prepolymerization reaction. After the prepolymerization is completed, add 4.66 g of dioctyltin oxide, raise the temperature to 245 °C and evacuate to make the absolute pressure of the reaction system drop below 100 Pa, and continue the reaction for 0.5 h; stop evacuating, replenish nitrogen to 50 kPa, and cool the high-temperature melt by water cooling - drying - pulverizing to prepare the double carboxyl-terminated PBT oligomer (D-PBT-1). The number-average molecular weight of the prepared double carboxyl-terminated PBT oligomer (D-PBT-1) is 1001, and the terminal carboxyl content is 1.999 mmol / g.

[0063] b. Preparation of double amino-terminated nylon 12 oligomer: Add 2000 g of laurolactam, 590 g of dodecanediamine and 240 g of ultrapure water into a 10 L reaction kettle, replace the nitrogen three times, heat up to 270 °C and keep it for 5 h to complete the ring-opening reaction of laurolactam; after the ring-opening is completed, release the pressure to atmospheric pressure, cool down to 180 °C while releasing the pressure, and then carry out vacuum treatment for 30 min to complete the melt polycondensation; after the melt polycondensation is completed, stop evacuating and protect with inert gas. The number-average molecular weight of the prepared double amino-terminated nylon 12 oligomer (D-PA12-1) is 1001, and the terminal amino content is 1.993 mmol / g;

[0064] c. Preparation of amphiphilic block copolymer: 2589 g of dicarboxyl-terminated PBT oligomer (D-PBT-1) and 37 g of adipic acid were added to a reaction kettle containing diamino-terminated nylon oligomer. After purging with nitrogen three times, the temperature was raised to 245 °C, and the vacuum was pumped to reduce the absolute pressure of the reaction system to less than 1 kPa. The reaction was continued for 45 min to cause an amidation reaction between the dicarboxyl-terminated PBT oligomer and the diamino-terminated nylon 12 oligomer to obtain a PBT and PA12 block copolymer (B-PBT / PA12-1). Then, through drawing - water cooling - pelletizing - drying, amphiphilic block copolymer pellets were obtained. The number-average molecular weight of this amphiphilic block copolymer was 20220.

[0065]

Preparation Example 2

[0066] The amphiphilic block copolymer was prepared according to the following steps

[0067] a. Preparation of dicarboxyl-terminated PBT oligomer: The dicarboxyl-terminated PBT oligomer (D-PBT-1) was prepared according to step a of Preparation Example 1.

[0068] b. Preparation of diamino-terminated nylon 12 oligomer: 2000 g of laurolactam, 257 g of dodecanediamine, and 240 g of ultrapure water were added to a 10 L reaction kettle. After purging with nitrogen three times, the temperature was raised to 280 °C and maintained for 5 h to complete the ring-opening reaction of laurolactam; after the ring-opening was completed, the pressure was released to atmospheric pressure, and the temperature was lowered to 200 °C while releasing the pressure. Then, vacuum treatment was carried out for 45 min to complete melt polycondensation; after the melt polycondensation was completed, the vacuum pumping was stopped, and it was protected by inert gas. The number-average molecular weight of the prepared diamino-terminated nylon 12 oligomer (D-PA12-2) was 2002, and the amino group content at the end was 0.999 mmol / g;

[0069] c. Preparation of amphiphilic block copolymer: 1128 g of dicarboxyl-terminated PBT oligomer (D-PBT-1) and 24.5 g of adipic acid were added to a reaction kettle containing diamino-terminated nylon oligomer (D-PA12-2). After purging with nitrogen three times, the temperature was raised to 245 °C, and the vacuum was pumped to reduce the absolute pressure of the reaction system to less than 1 kPa. The reaction was continued for 45 min to cause an amidation reaction between the dicarboxyl-terminated PBT oligomer and the diamino-terminated nylon 12 oligomer to obtain a PBT and PA12 block copolymer (B-PBT / PA12-2). Then, through drawing - water cooling - pelletizing - drying, amphiphilic block copolymer pellets were obtained. The number-average molecular weight of this amphiphilic block copolymer was 20100.

[0070]

Preparation Example 3

[0071] The amphiphilic block copolymer was prepared according to the following steps

[0072] a. Preparation of dicarboxyl - terminated PBT oligomer: Prepare the dicarboxyl - terminated PBT oligomer (D - PBT - 1) according to step a of Preparation Example 1.

[0073] b. Preparation of diamino - terminated nylon 12 oligomer: Add 2000 g of laurolactam, 165 g of dodecanediamine, and 240 g of ultrapure water into a 10 - L reaction kettle. Replace the air with nitrogen three times, heat up to 280 °C and keep it for 5 h to complete the ring - opening reaction of laurolactam. After the ring - opening reaction is completed, relieve the pressure to normal pressure. While relieving the pressure, cool down to 200 °C, and then carry out vacuum treatment for 45 min to complete melt polycondensation. After the melt polycondensation is completed, stop vacuum pumping and protect it with inert gas. The number - average molecular weight of the prepared diamino - terminated nylon 12 oligomer (D - PA12 - 3) is 2992, and the terminal amino group content is 0.669 mmol / g.

[0074] c. Preparation of amphiphilic block copolymer: Put 724 g of dicarboxyl - terminated PBT oligomer and 21 g of adipic acid into the reaction kettle containing diamino - terminated nylon oligomer (D - PA12 - 3). After replacing the air with nitrogen 3 times, heat up to 245 °C, evacuate to make the absolute pressure of the reaction system drop below 1 kPa, and continue to react for 45 min to make the dicarboxyl - terminated PBT oligomer and the diamino - terminated nylon 12 oligomer undergo amidation reaction to obtain the PBT - PA12 block copolymer (B - PBT / PA12 - 3). Then, through drawing - water cooling - pelletizing - drying, the amphiphilic block copolymer pellets are obtained. The number - average molecular weight of this amphiphilic block copolymer is 20050.

[0075]

Preparation Example 4

[0076] Prepare the amphiphilic block copolymer according to the following steps

[0077] a. Preparation of dicarboxyl - terminated PBT oligomer: Add 2064 g of terephthalic acid (PTA), 1000 g of 1,4 - butanediol (BDO), and 2.06 g of dioctyltin oxide into the reaction kettle. Replace the air with nitrogen 3 times, heat up to 240 °C and keep it for 1 h for esterification reaction. After the esterification reaction is completed, keep the temperature at 240 °C and purge with nitrogen for 0.75 h for prepolymerization reaction. After the prepolymerization is completed, add 4.12 g of dioctyltin oxide, heat up to 245 °C and evacuate to make the absolute pressure of the reaction system drop below 100 Pa, and continue to react for 1 h. Stop vacuum pumping, add nitrogen to 50 kPa, and cool the high - temperature melt through water cooling - drying - pulverizing to prepare the dicarboxyl - terminated PBT oligomer (D - PBT - 2). The number - average molecular weight of the prepared dicarboxyl - terminated PBT oligomer is 2007, and the terminal carboxyl group content is 0.996 mmol / g.

[0078] b. Preparation of diamine-terminated nylon 12 oligomer: Prepare diamine-terminated PA12 oligomer (D-PA12-1) according to step b of Preparation Example 1.

[0079] c. Preparation of amphiphilic block copolymer: Charge 4526 g of dicarboxyl-terminated PBT oligomer (D-PBT-2) and 56 g of adipic acid into the reaction kettle containing diamine-terminated nylon oligomer (D-PA12-1). After purging with nitrogen three times, heat up to 245 °C, evacuate to make the absolute pressure of the reaction system drop below 1 kPa, and continue the reaction for 45 min to carry out amidation reaction between dicarboxyl-terminated PBT oligomer and diamine-terminated nylon 12 oligomer to obtain PBT and PA12 block copolymer (B-PBT / PA12-4). Then, through drawing - water cooling - pelletizing - drying, amphiphilic block copolymer pellets are obtained. The number-average molecular weight of this amphiphilic block copolymer is 20210.

[0080]

Preparation Example 5

[0081] Prepare amphiphilic block copolymer according to the following steps

[0082] a. Preparation of dicarboxyl-terminated PBT oligomer: Prepare dicarboxyl-terminated PBT oligomer (D-PBT-2) according to step a of Preparation Example 4.

[0083] b. Preparation of diamine-terminated nylon 12 oligomer: Prepare diamine-terminated PA12 oligomer (D-PA12-2) according to step b of Preparation Example 2.

[0084] c. Preparation of amphiphilic block copolymer: Charge 2170 g of dicarboxyl-terminated PBT oligomer (D-PBT-2) and 32.5 g of adipic acid into the reaction kettle containing diamine-terminated nylon oligomer (D-PA12-2). After purging with nitrogen three times, heat up to 245 °C, evacuate to make the absolute pressure of the reaction system drop below 1 kPa, and continue the reaction for 45 min to carry out amidation reaction between dicarboxyl-terminated PBT oligomer and diamine-terminated nylon 12 oligomer to obtain PBT and PA12 block copolymer (B-PBT / PA12-5). Then, through drawing - water cooling - pelletizing - drying, amphiphilic block copolymer pellets are obtained. The number-average molecular weight of this amphiphilic block copolymer is 20230.

[0085]

Preparation Example 6

[0086] Prepare amphiphilic block copolymer according to the following steps

[0087] a. Preparation of dicarboxyl - terminated PBT oligomer: Add 1987 g of terephthalic acid (PTA), 1000 g of 1,4 - butanediol (BDO) and 1.99 g of tetrabutyl titanate into the reaction kettle, replace the nitrogen in the kettle for 3 times, heat up to 240 °C and keep it for 1.5 h for the esterification reaction. After the esterification reaction is completed, keep the temperature at 240 °C and purge with nitrogen for 0.75 h for the prepolymerization reaction. After the prepolymerization is completed, add 3.98 g of tetrabutyl titanate, heat up to 245 °C and evacuate to make the absolute pressure of the reaction system drop below 100 Pa, and continue the reaction for 1.5 h; stop evacuating, replenish nitrogen to 75 kPa, and cool the high - temperature melt by water cooling - drying - pulverizing to prepare the dicarboxyl - terminated PBT oligomer (D - PBT - 3). The number - average molecular weight of the prepared dicarboxyl - terminated PBT oligomer is 2995, and the carboxyl - end - group content is 0.668 mmol / g.

[0088] b. Preparation of diamino - terminated nylon 12 oligomer: Prepare the diamino - terminated PA12 oligomer (D - PA12 - 2) according to the steps of Preparation Example 2, step b.

[0089] c. Preparation of amphiphilic block copolymer: Put 2167 g of dicarboxyl - terminated PBT oligomer (D - PBT - 3) and 27.5 g of adipic acid into the reaction kettle containing the diamino - terminated nylon oligomer (D - PA12 - 2). After replacing the nitrogen 3 times, heat up to 245 °C, evacuate to make the absolute pressure of the reaction system drop below 1 kPa, and continue the reaction for 45 min to cause the amidation reaction between the dicarboxyl - terminated PBT oligomer and the diamino - terminated nylon 12 oligomer to obtain the PBT and PA12 block copolymer (B - PBT / PA12 - 6). Then, through drawing - water cooling - pelletizing - drying, the amphiphilic block copolymer pellets are obtained. The number - average molecular weight of this amphiphilic block copolymer is 29820.

[0090]

Preparation Example 7

[0091] Prepare the amphiphilic block copolymer according to the following steps

[0092] a. Preparation of dicarboxyl - terminated PBT oligomer: Prepare the dicarboxyl - terminated PBT oligomer (D - PBT - 3) according to the steps of Preparation Example 6, step a.

[0093] b. Preparation of diamine-terminated nylon 12 oligomer: Add 2000 g of laurolactam, 122 g of decanediamine and 240 g of ultrapure water into a 10 L reaction kettle, replace the air with nitrogen three times, heat up to 280 °C and keep it for 5 h to complete the ring-opening reaction of laurolactam; after the ring-opening is completed, release the pressure to atmospheric pressure, cool down to 200 °C while releasing the pressure, and then carry out vacuum treatment for 45 min to complete melt polycondensation; after the melt polycondensation is completed, stop vacuum pumping and protect with inert gas. The number-average molecular weight of the prepared diamine-terminated nylon 12 oligomer (D-PA12-4) is 2997, and the amino group content at the end is 0.667 mmol / g.

[0094] c. Preparation of amphiphilic block copolymer: Put 2588 g of dicarboxyl-terminated PBT oligomer (D-PBT-3) and 95 g of dodecanedioic acid into the reaction kettle containing diamine-terminated nylon oligomer (D-PA12-4), replace the air with nitrogen 3 times, then heat up to 245 °C, evacuate to make the absolute pressure of the reaction system drop below 1 kPa, and continue to react for 30 min to make the dicarboxyl-terminated PBT oligomer react with the diamine-terminated nylon 12 oligomer to obtain a PBT and PA12 block copolymer (B-PBT / PA12-7), and then obtain amphiphilic block copolymer pellets through drawing - water cooling - pelletizing - drying. The number-average molecular weight of this amphiphilic block copolymer is 10400.

[0095]

Preparation of Comparative Example 8

[0096] Prepare an amphiphilic block copolymer according to the following steps

[0097] a. Preparation of dicarboxyl-terminated PBT oligomer: Prepare the dicarboxyl-terminated PBT oligomer (D-PBT-2) according to step a of Preparation Example 4.

[0098] b. Preparation of diamine-terminated nylon 12 oligomer: Prepare the diamine-terminated PA12 oligomer (D-PA12-2) according to step b of Preparation Example 2.

[0099] c. Preparation of amphiphilic block copolymer: Put 2170 g of dicarboxyl-terminated PBT oligomer (D-PBT-2) and 100 g of adipic acid into the reaction kettle containing diamine-terminated nylon oligomer (D-PA12-2), replace the air with nitrogen 3 times, then heat up to 245 °C, evacuate to make the absolute pressure of the reaction system drop below 1 kPa, and continue to react for 30 min to make the dicarboxyl-terminated PBT oligomer react with the diamine-terminated nylon 12 oligomer to obtain a PBT and PA12 block copolymer (B-PBT / PA12-1'), and then obtain amphiphilic block copolymer pellets through drawing - water cooling - pelletizing - drying. The number-average molecular weight of this amphiphilic block copolymer is 5200.

[0100]

Preparation of Comparative Example 9

[0101] The amphiphilic block copolymer is prepared according to the following steps

[0102] a. Preparation of double carboxyl-terminated PBT oligomer: Prepare double carboxyl-terminated PBT oligomer (D-PBT-2) according to step a of Preparation Example 4

[0103] b. Preparation of double amino-terminated nylon 12 oligomer: Prepare double amino-terminated PA12 oligomer (D-PA12-2) according to step b of Preparation Example 2

[0104] c. Preparation of amphiphilic block copolymer: Charge 2170 g of double carboxyl-terminated PBT oligomer (D-PBT-2) and 10 g of adipic acid into the reaction kettle containing double amino-terminated nylon oligomer (D-PA12-2). After purging with nitrogen three times, heat up to 245 °C, evacuate to make the absolute pressure of the reaction system drop below 1 kPa, and continue the reaction for 60 min to carry out amidation reaction between double carboxyl-terminated PBT oligomer and double amino-terminated nylon 12 oligomer to obtain PBT and PA12 block copolymer (B-PBT / PA12-2’). Then, through drawing - water cooling - pelletizing - drying, amphiphilic block copolymer pellets are obtained. The number-average molecular weight of this amphiphilic block copolymer is 65500

[0105]

Preparation Comparative Example 10

[0106] The amphiphilic block copolymer is prepared according to the following steps

[0107] a. Preparation of double carboxyl-terminated PBT oligomer: Add 1913 g of terephthalic acid (PTA), 1000 g of 1,4-butanediol (BDO) and 1.91 g of dioctyltin oxide into the reaction kettle, purge with nitrogen three times, heat up to 240 °C and keep for 3 h for esterification reaction. After the esterification reaction is completed, keep at 240 °C and purge with nitrogen for 1 h for prepolymerization reaction. After prepolymerization is completed, add 3.82 g of dioctyltin oxide, heat up to 245 °C and evacuate to make the absolute pressure of the reaction system drop below 100 Pa, and continue the reaction for 2 h; stop evacuating, add nitrogen to 100 kPa, and cool the high-temperature melt by water cooling - drying - pulverizing to prepare double carboxyl-terminated PBT oligomer (D-PBT-10). The number-average molecular weight of the prepared double carboxyl-terminated PBT oligomer is 6004, and the terminal carboxyl content is 0.333 mmol / g

[0108] b. Preparation of diamino-terminated nylon 12 oligomer: Add 2000 g of laurolactam, 79 g of dodecamethylenediamine, and 240 g of ultrapure water into a 10 L reaction kettle. Replace the air with nitrogen three times, heat up to 290 °C and maintain for 5 h to complete the ring-opening reaction of laurolactam. After the ring-opening reaction is completed, release the pressure to atmospheric pressure, cool down to 220 °C while releasing the pressure, and then perform vacuum treatment for 60 min to complete melt polycondensation. After the melt polycondensation is completed, stop vacuum pumping and protect with inert gas. The number-average molecular weight of the prepared diamino-terminated nylon 12 oligomer (D-PA12-10) is 6000, and the amino end group content is 0.333 mmol / g;

[0109] c. Preparation of amphiphilic block copolymer: Put 2080 g of dicarboxyl-terminated PBT oligomer (D-PBT-10) and 30 g of adipic acid into the reaction kettle containing the diamino-terminated nylon oligomer. After replacing the air with nitrogen 3 times, heat up to 245 °C, evacuate to make the absolute pressure of the reaction system drop below 1 kPa, and continue the reaction for 45 min to cause the amidation reaction between the dicarboxyl-terminated PBT oligomer and the diamino-terminated nylon 12 oligomer to obtain a PBT / PA12 block copolymer (B-PBT / PA12-3’). After that, it is drawn - water-cooled - pelletized - dried to obtain amphiphilic block copolymer pellets. The number-average molecular weight of this amphiphilic block copolymer is 20320.

[0110] Example 1

[0111] Prepare PBT / PA12 sharpened filaments according to the following method:

[0112] (1) Preparation steps of PBT / PA12 blended pellet: Add 9 kg of polybutylene terephthalate (Nanchenxing Synthetic Materials Co., PBT1100 AFL, relative viscosity 0.75), 1 kg of nylon 12 (Ube, Japan, 3020U, relative viscosity 1.80), 100 g of B-PBT / PA12-1 compatibilizer, 30 g of lubricant EBS, and 30 g of compound antioxidant (equal-mass compound of antioxidant 1098 and antioxidant 168) into a high-speed mixer and mix for 20 min to obtain a blended material. Then, use a twin-screw extruder with a length-diameter ratio of 40 to perform melt blending extrusion - water-cooling - pelletizing - drying to prepare PBT / PA12 blended pellets. The screw speed is 100 rpm, and the temperature from the feeding section to the die head is set at 180 - 250 °C.

[0113] (2) Steps for preparing the bobbin: The compounded granular material prepared in step (1) is plasticized by a single-screw extruder with a length-diameter ratio of 25, extruded through a spinneret plate, water-cooled and shaped, heat-drawn, wound and collected on a roller, heat-treated and hardened, and then encapsulated and cut to prepare the bobbin. The rotational speed of the single-screw extruder is 100 rpm, and the temperature from the feeding section to the head is set at 200 - 280 °C; the heat drawing is carried out in a hot oven at 160 °C with a draw ratio of 4; the diameter of the monofilament after heat drawing is 7 mil; the filament bundle is heat-treated and hardened using a nitrogen-filled oven with a temperature of 120 °C and a treatment time of 2 h; the diameter of the bobbin after cutting is 50 ± 2 mm, and the height is 30 ± 2 mm.

[0114] (3) Steps for tip-grinding the bobbin: The bobbin prepared in step (2) is placed in a bobbin tip-grinding groove filled with tip-grinding liquid for tip-grinding treatment, cleaning, and drying to prepare tip-ground toothbrush filaments. The tip-grinding liquid used is an aqueous NaOH solution with a concentration of 30%; the treatment temperature is 120 °C; the treatment time is 40 min; after the bobbin tip-grinding is completed, the bobbin is washed with clean water until it shows neutrality (pH = 7), and then dried in a vacuum oven at 80 °C for 12 h to obtain the finished tip-ground toothbrush filaments.

[0115] Example 2

[0116] The PBT / PA12 tip-ground filaments are prepared according to the following method:

[0117] (1) Steps for preparing the PBT / PA12 compounded granular material: 7.5 kg of polybutylene terephthalate (Nanxingchen Synthetic Materials Co., PBT1100 AFL, relative viscosity of 0.75), 2.5 kg of nylon 12 (Ube Industries, Japan, 3020U, relative viscosity of 1.80), 300 g of B-PBT / PA12-2 compatibilizer, 30 g of lubricant EBS, and 10 g of a compound antioxidant (an equal-mass compound of antioxidant 1098 and antioxidant 168) are added to a high-speed mixer and mixed for 20 min to obtain a compounded material. Then, the compounded material is melt-blended and extruded, water-cooled, pelletized, and dried using a twin-screw extruder with a length-diameter ratio of 45 to prepare the PBT / PA12 compounded granular material. The rotational speed of the screw is 100 rpm, and the temperature from the feeding section to the head is set at 180 - 250 °C.

[0118] (2) Steps for preparing the bobbin: The compounded granular materials prepared in step (1) are plasticized by a single-screw extruder with a length-diameter ratio of 30, extruded through a spinneret, water-cooled and shaped, heat-stretched, wound on a roller, heat-treated and hardened, and encapsulated and cut to prepare the bobbin. The rotation speed of the single-screw extruder is 100 rpm, and the temperature from the feeding section to the head is set at 200 - 280 °C; the heat stretching is carried out in a hot oven at 150 °C with a stretching ratio of 4; the diameter of the single filament after heat stretching is 7 mil; the filament bundle is heat-treated and hardened using a nitrogen-filled oven with a temperature of 120 °C and a treatment time of 2 h; the bundled diameter of the cut bobbin is 50 ± 2 mm, and the height is 30 ± 2 mm.

[0119] (3) Steps for tip-grinding the bobbin: The bobbin prepared in step (2) is placed in a bobbin tip-grinding groove filled with tip-grinding liquid for tip-grinding treatment, cleaning, and drying to prepare tip-ground toothbrush filaments. The tip-grinding liquid used is an aqueous NaOH solution with a concentration of 30%; the treatment temperature is 120 °C; the treatment time is 80 min; after the tip-grinding of the bobbin is completed, the bobbin is washed with water until it shows neutrality (pH = 7), and then dried in a vacuum oven at 80 °C for 12 h to obtain the finished tip-ground toothbrush filaments.

[0120] Example 3

[0121] The PBT / PA12 tip-ground filaments are prepared according to the following method:

[0122] (1) Steps for preparing the PBT / PA12 compounded granular materials: 6 kg of polybutylene terephthalate (Nanchenxing Synthetic Materials Company, PBT1100 AFL, relative viscosity of 0.75), 4 kg of nylon 12 (Ube, Japan, 3020U, relative viscosity of 1.80), 500 g of B-PBT / PA12-3 compatibilizer, 30 g of lubricant EBS, and 30 g of a compound antioxidant (an equal-mass compound of antioxidant 1098 and antioxidant 168) are added to a high-speed mixer and mixed for 20 min to obtain a compounded material. Then, the compounded material is melt-blended and extruded, water-cooled, pelletized, and dried using a twin-screw extruder with a length-diameter ratio of 42 to prepare the PBT / PA12 compounded granular materials. The rotation speed of the screw is 100 rpm, and the temperature from the feeding section to the head is set at 180 - 250 °C.

[0123] (2) Steps for preparing the bobbin: The compounded granular materials prepared in step (1) are plasticized by a single-screw extruder with a length-diameter ratio of 28, extruded through a spinneret, water-cooled and shaped, heat-stretched, wound on a roller, heat-treated and hardened, and encapsulated and cut to prepare the bobbin. The rotation speed of the single-screw extruder is 100 rpm, and the temperature from the feeding section to the head is set at 200 - 280 °C; the heat stretching is carried out in a hot oven at 140 °C with a stretching ratio of 4; the diameter of the single filament after heat stretching is 7 mil; the filament bundle is heat-treated and hardened using a nitrogen-filled oven with a temperature of 120 °C and a treatment time of 2 h; the bundled diameter of the cut bobbin is 50 ± 2 mm, and the height is 30 ± 2 mm.

[0124] (3) Steps for tip sharpening of the bobbin: Place the bobbin prepared in step (2) into a bobbin tip sharpening groove filled with tip sharpening liquid for tip sharpening - cleaning - drying to prepare tip sharpened toothbrush filaments. The tip sharpening liquid used is an aqueous NaOH solution with a concentration of 50%; the treatment temperature is 140 °C; the treatment time is 80 min; after the tip sharpening of the bobbin is completed, wash the bobbin with clear water until it shows neutrality (PH = 7), and then dry it in a vacuum oven at 80 °C for 12 h to obtain the finished tip sharpened toothbrush filaments.

[0125] Example 4

[0126] Prepare PBT / PA12 tip sharpened filaments according to the following method:

[0127] (1) Steps for preparing PBT / PA12 blended pellets: Add 7.5 kg of polybutylene terephthalate (Nanchenxing Synthetic Materials Company, PBT1100 AFL, relative viscosity of 0.75), 2.5 kg of nylon 12 (Evonik Germany, L1940, relative viscosity of 1.89), 300 g of B-PBT / PA12-4 compatibilizer, 10 g of lubricant EBS, and 50 g of compound antioxidant (an equal mass compound of antioxidant 1098 and antioxidant 168) into a high-speed mixer and mix for 20 min to obtain a blended material. Then, extrude the blended material through a twin-screw extruder with a length-diameter ratio of 42 for melt blending extrusion - water cooling - pelletizing - drying to prepare PBT / PA12 blended pellets. The screw speed is 100 rpm, and the temperature from the feeding section to the die head is set at 180 - 250 °C.

[0128] (2) Steps for preparing the bobbin: Plasticize the blended pellets prepared in step (1) through a single-screw extruder with a length-diameter ratio of 28 - extrude through a spinneret - water cooling and shaping - hot stretching - winding and rolling - heat treatment hardening - encapsulation and cutting to prepare the bobbin. The speed of the single-screw extruder is 100 rpm, and the temperature from the feeding section to the die head is set at 200 - 280 °C; the hot stretching is carried out in a hot oven at 150 °C with a stretching ratio of 4; the diameter of the single filament after hot stretching is 7 mil; use a nitrogen-filled oven to carry out heat treatment hardening on the filament bundle, the temperature of the nitrogen-filled oven is 120 °C, and the treatment time is 2 h; the bundled diameter of the cut bobbin is 50 ± 2 mm, and the height is 30 ± 2 mm.

[0129] (3) Steps for tip sharpening of the bobbin: Place the bobbin prepared in step (2) into a bobbin tip sharpening groove filled with tip sharpening liquid for tip sharpening - cleaning - drying to prepare tip sharpened toothbrush filaments. The tip sharpening liquid used is an aqueous NaOH solution with a concentration of 40%; the treatment temperature is 120 °C; the treatment time is 60 min; after the tip sharpening of the bobbin is completed, wash the bobbin with clear water until it shows neutrality (PH = 7), and then dry it in a vacuum oven at 80 °C for 12 h to obtain the finished tip sharpened toothbrush filaments.

[0130] Example 5

[0131] The PBT / PA12 sharpened filaments are prepared according to the following method:

[0132] (1) Preparation steps of PBT / PA12 blended pellets: 7.5 kg of polybutylene terephthalate (Nanxingchen Synthetic Materials Co., PBT1100 AFL, relative viscosity 0.75), 2.5 kg of nylon 12 (Ube Industries, Japan, 3020U, relative viscosity 1.80), 300 g of B-PBT / PA12-5 compatibilizer, 30 g of lubricant EBS, and 30 g of compound antioxidant (equal mass compound of antioxidant 1098 and antioxidant 168) are added to a high-speed mixer and mixed for 20 min to obtain a blended material. Then, the blended material is melt-blended, extruded, water-cooled, pelletized, and dried using a twin-screw extruder with a length-diameter ratio of 42 to prepare PBT / PA12 blended pellets. The screw speed is 100 rpm, and the temperature from the feeding section to the die head is set at 180 - 250 °C.

[0133] (2) Preparation steps of the bobbin: The blended pellets prepared in step (1) are plasticized by a single-screw extruder with a length-diameter ratio of 28, extruded through a spinneret, water-cooled and shaped, hot-stretched, wound on a roll, heat-treated and hardened, and packaged and cut to prepare the bobbin. The speed of the single-screw extruder is 100 rpm, and the temperature from the feeding section to the die head is set at 200 - 280 °C; the hot stretching is carried out in a hot oven at 150 °C with a stretching ratio of 4; the diameter of the single filament after hot stretching is 7 mil; the filament bundle is heat-treated and hardened using a nitrogen-filled oven, the temperature of the nitrogen-filled oven is 120 °C, and the treatment time is 2 h; the diameter of the cut bobbin bundle is 50 ± 2 mm, and the height is 30 ± 2 mm.

[0134] (3) Sharpened treatment steps of the bobbin: The bobbin prepared in step (2) is placed in a bobbin sharpening groove filled with a sharpening liquid for sharpening treatment, washing, and drying to prepare sharpened toothbrush filaments. The sharpening liquid used is an aqueous NaOH solution with a concentration of 30%; the treatment temperature is 140 °C; the treatment time is 60 min; after the bobbin sharpening is completed, the bobbin is washed with water until it shows neutrality (PH = 7), and then dried in a vacuum oven at 80 °C for 12 h to obtain the finished sharpened toothbrush filaments.

[0135] Example 6

[0136] The PBT / PA12 sharpened filaments are prepared according to the following method:

[0137] (1) Preparation steps of PBT / PA12 blended pellets: Add 7.5 kg of polybutylene terephthalate (Nanchenxing Synthetic Materials Company, PBT1100 AFL, relative viscosity of 0.75), 2.5 kg of nylon 12 (Ube of Japan, 3020U, relative viscosity of 1.80), 300 g of B-PBT / PA12-6 compatibilizer, 50 g of lubricant EBS, and 30 g of compound antioxidant (equal mass compound of antioxidant 1098 and antioxidant 168) into a high-speed mixer and mix for 20 min to obtain a blended material. Then, use a twin-screw extruder with a length-diameter ratio of 42 to carry out melt blending extrusion - water cooling - pelletizing - drying to prepare PBT / PA12 blended pellets. The screw speed is 100 rpm, and the temperature from the feeding section to the die head is set at 180 - 250 °C.

[0138] (2) Preparation steps of the bobbin: Plasticize the blended pellets prepared in step (1) through a single-screw extruder with a length-diameter ratio of 28 - extrude through a spinneret - water cooling and shaping - hot stretching - winding and rolling - heat treatment hardening - encapsulation and cutting to prepare the bobbin. The speed of the single-screw extruder is 150 rpm, and the temperature from the feeding section to the die head is set at 200 - 280 °C; the hot stretching is carried out in a hot oven at 150 °C, and the stretching ratio is 5; the diameter of the single filament after hot stretching is 7 mil; use a nitrogen-filled oven to carry out heat treatment hardening on the filament bundle, the temperature of the nitrogen-filled oven is 120 °C, and the treatment time is 2 h; the bundle diameter of the cut bobbin is 50 ± 2 mm, and the height is 30 ± 2 mm.

[0139] (3) Steps for sharpening the bobbin: Place the bobbin prepared in step (2) in a bobbin sharpening groove filled with a sharpening liquid for sharpening treatment - cleaning - drying to prepare sharpened toothbrush filaments. The sharpening liquid used is an aqueous NaOH solution with a concentration of 40%; the treatment temperature is 100 °C; the treatment time is 80 min; after the bobbin sharpening is completed, wash the bobbin with clean water until it shows neutrality (PH = 7), and then dry it in a vacuum oven at 80 °C for 12 h to obtain the finished sharpened toothbrush filaments.

[0140] Example 7

[0141] Prepare PBT / PA12 sharpened filaments according to the following method:

[0142] (1) Preparation steps of PBT / PA12 blended pellets: Add 7.5 kg of polybutylene terephthalate (Nanxingchen Synthetic Materials Co., PBT1100 AFL, relative viscosity 0.75), 2.5 kg of nylon 12 (Ube of Japan, 3020U, relative viscosity 1.80), 300 g of B-PBT / PA12-7 compatibilizer, 30 g of lubricant EBS, and 30 g of compound antioxidant (equal mass compound of antioxidant 1098 and antioxidant 168) into a high-speed mixer and mix for 20 min to obtain a blended material. Then, use a twin-screw extruder with a length-diameter ratio of 42 to carry out melt blending extrusion - water cooling - pelletizing - drying to prepare PBT / PA12 blended pellets. The screw speed is 100 rpm, and the temperature from the feeding section to the die head is set at 180 - 250 °C.

[0143] (2) Preparation steps of the bobbin: Plasticize the blended pellets prepared in step (1) through a single-screw extruder with a length-diameter ratio of 28 - extrude through a spinneret - water cooling and shaping - hot stretching - winding and rolling - heat treatment and hardening - encapsulation and cutting to prepare the bobbin. The speed of the single-screw extruder is 100 rpm, and the temperature from the feeding section to the die head is set at 200 - 280 °C; the hot stretching is carried out in a hot oven at 150 °C, and the stretching ratio is 4; the diameter of the single filament after hot stretching is 7 mil; use a nitrogen-filled oven to carry out heat treatment and hardening on the filament bundle, the temperature of the nitrogen-filled oven is 120 °C, and the treatment time is 2 h; the bundle diameter of the cut bobbin is 50 ± 2 mm, and the height is 30 ± 2 mm.

[0144] (3) Steps for tip sharpening treatment of the bobbin: Place the bobbin prepared in step (2) in a bobbin tip sharpening groove filled with tip sharpening liquid for tip sharpening treatment - cleaning - drying to prepare sharpened toothbrush filaments. The tip sharpening liquid used is an aqueous NaOH solution with a concentration of 40%; the treatment temperature is 120 °C; the treatment time is 60 min; after the tip sharpening of the bobbin is completed, wash the bobbin with clean water until it shows neutrality (PH = 7), and then dry it in a vacuum oven at 80 °C for 12 h to obtain the finished sharpened toothbrush filaments.

[0145] Comparative Example 1

[0146] Prepare PBT sharpened filaments according to the following method:

[0147] (1) Preparation steps of PBT / antioxidant / lubricant blended pellets: Add 10 kg of polybutylene terephthalate (NXC Synthetic Materials Co., PBT1100 AFL, relative viscosity 0.75), 30 g of lubricant EBS, and 30 g of compound antioxidant (equal mass blend of antioxidant 1098 and antioxidant 168) into a high-speed mixer and mix for 20 min to obtain a blended material. Then, use a twin-screw extruder with a length-diameter ratio of 42 to perform melt blending extrusion - water cooling - pelletizing - drying to prepare PBT / antioxidant / lubricant blended pellets. The screw speed is 100 rpm, and the temperature from the feeding section to the die head is set at 180 - 250 °C.

[0148] (2) Preparation steps of the yarn cake: Prepare the PBT yarn cake from the above-mentioned PBT / antioxidant / lubricant blended pellets according to the steps (2) of Example 5.

[0149] (3) Steps for sharpening the yarn cake: Prepare the sharpened PBT toothbrush filaments from the above-mentioned PBT / antioxidant / lubricant yarn cake according to the steps (3) of Example 5.

[0150] Comparative Example 2

[0151] Prepare the sharpened PBT / PA12 filaments according to the following method:

[0152] (1) Preparation steps of PBT / PA12 blended pellets: Add 7.5 kg of polybutylene terephthalate (NXC Synthetic Materials Co., PBT1100 AFL, relative viscosity 0.75), 2.5 kg of nylon 12 (UBE of Japan, 3020U, relative viscosity 1.80), 30 g of lubricant EBS, and 30 g of compound antioxidant (equal mass blend of antioxidant 1098 and antioxidant 168) into a high-speed mixer and mix for 20 min to obtain a blended material. Then, use a twin-screw extruder with a length-diameter ratio of 42 to perform melt blending extrusion - water cooling - pelletizing - drying to prepare PBT / PA12 blended pellets. The screw speed is 100 rpm, and the temperature from the feeding section to the die head is set at 180 - 250 °C.

[0153] (2) Preparation steps of the yarn cake: Prepare the PBT / PA12 yarn cake from the above-mentioned PBT / PA12 blended pellets according to the steps (2) of Example 5.

[0154] (3) Steps for sharpening the yarn cake: Prepare the sharpened PBT / PA12 toothbrush filaments from the above-mentioned PBT / PA12 yarn cake according to the steps (3) of Example 5.

[0155] Comparative Example 3

[0156] Prepare the sharpened PBT / PA12 filaments according to the following method:

[0157] (1) Preparation steps of PBT / PA12 blended pellets: Add 7.5 kg of polybutylene terephthalate (Nanxingchen Synthetic Materials Co., PBT1100 AFL, relative viscosity 0.75), 2.5 kg of nylon 12 (Ube Industries, Japan, 3020U, relative viscosity 1.80), 300 g of B-PBT / PA12-1' compatibilizer, 30 g of lubricant EBS, and 30 g of compound antioxidant (equal mass compound of antioxidant 1098 and antioxidant 168) into a high-speed mixer and mix for 20 min to obtain a blended material. Then, use a twin-screw extruder with a length-diameter ratio of 42 to carry out melt blending extrusion - water cooling - pelletizing - drying to prepare PBT / PA12 blended pellets. The screw speed is 100 rpm, and the temperature from the feeding section to the die head is set at 180 - 250 °C.

[0158] (2) Preparation steps of the bobbin: Prepare the PBT / PA12 bobbin from the above PBT / PA12 blended pellets according to the steps (2) of Example 5.

[0159] (3) Tip sharpening treatment steps of the bobbin: Prepare the PBT / PA12 tip-sharpened toothbrush filaments from the above PBT / PA12 bobbin according to the steps (3) of Example 5.

[0160] Comparative Example 4

[0161] Prepare PBT / PA12 tip-sharpened filaments according to the following method:

[0162] (1) Preparation steps of PBT / PA12 blended pellets: Add 7.5 kg of polybutylene terephthalate (Nanxingchen Synthetic Materials Co., PBT1100 AFL, relative viscosity 0.75), 2.5 kg of nylon 12 (Ube Industries, Japan, 3020U, relative viscosity 1.80), 300 g of B-PBT / PA12-2' compatibilizer, 30 g of lubricant EBS, and 30 g of compound antioxidant (equal mass compound of antioxidant 1098 and antioxidant 168) into a high-speed mixer and mix for 20 min to obtain a blended material. Then, use a twin-screw extruder with a length-diameter ratio of 42 to carry out melt blending extrusion - water cooling - pelletizing - drying to prepare PBT / PA12 blended pellets. The screw speed is 100 rpm, and the temperature from the feeding section to the die head is set at 180 - 250 °C.

[0163] (2) Preparation steps of the bobbin: Prepare the PBT / PA12 bobbin from the above PBT / PA12 blended pellets according to the steps (2) of Example 5.

[0164] (3) Tip sharpening treatment steps of the bobbin: Prepare the PBT / PA12 tip-sharpened toothbrush filaments from the above PBT / PA12 bobbin according to the steps (3) of Example 5.

[0165] Comparative Example 5

[0166] Prepare PBT / PA12 sharpened filaments according to the following method:

[0167] (1) Preparation steps of PBT / PA12 compound granules: Add 4 kg of polybutylene terephthalate (Nanxingchen Synthetic Materials Co., PBT1100 AFL, relative viscosity 0.75), 6 kg of nylon 12 (Ube Industries, Japan, 3020U, relative viscosity 1.80), 300 g of B-PBT / PA12-5 compatibilizer, 30 g of lubricant EBS, and 30 g of compound antioxidant (equal-mass compound of antioxidant 1098 and antioxidant 168) into a high-speed mixer and mix for 20 min to obtain a compound mixture. Then, use a twin-screw extruder with a length-diameter ratio of 42 to carry out melt blending extrusion - water cooling - pelletizing - drying to prepare PBT / PA12 compound granules. The screw speed is 100 rpm, and the temperature from the feeding section to the die head is set at 180 - 250 °C.

[0168] (2) Preparation steps of the filament cake: Prepare a PBT / PA12 filament cake from the above PBT / PA12 compound granules according to the steps of Example 5 (2).

[0169] (3) Sharpened treatment steps of the filament cake: Carry out sharpened treatment on the above PBT / PA12 filament cake according to the steps of Example 5 (3). After reaching the set time, it is found that the end of the brush filament is not sharpened, indicating that the brush filament prepared by this formula cannot be sharpened using a NaOH solution.

[0170] Comparative Example 6

[0171] Prepare PBT / PA12 sharpened filaments according to the following method:

[0172] (1) Preparation steps of PBT / PA12 compound granules: Add 7.5 kg of polybutylene terephthalate (Nanxingchen Synthetic Materials Co., PBT1100 AFL, relative viscosity 0.75), 2.5 kg of nylon 12 (Ube Industries, Japan, 3020U, relative viscosity 1.80), 300 g of B-PBT / PA12-3' compatibilizer, 30 g of lubricant EBS, and 30 g of compound antioxidant (equal-mass compound of antioxidant 1098 and antioxidant 168) into a high-speed mixer and mix for 20 min to obtain a compound mixture. Then, use a twin-screw extruder with a length-diameter ratio of 42 to carry out melt blending extrusion - water cooling - pelletizing - drying to prepare PBT / PA12 compound granules. The screw speed is 100 rpm, and the temperature from the feeding section to the die head is set at 180 - 250 °C.

[0173] (2) Preparation steps of the filament cake: Prepare a PBT / PA12 filament cake from the above PBT / PA12 compound granules according to the steps of Example 5 (2).

[0174] (3) Steps for sharpening the bobbin: Prepare the above PBT / PA12 bobbin into PBT / PA12 sharpened toothbrush filaments according to step (3) of Example 5.

[0175] To characterize the anti-collapse performance of the toothbrush filaments prepared in each example, the toothbrush filaments prepared in each example were made into standard toothbrushes, and tested with a 335 g weight for 24 h at a testing speed of 13 mm / s. The anti-collapse effect of the toothbrush filaments was determined according to the proportion of collapsed toothbrush filaments. The evaluation criteria are as follows: no collapse: 0 - 30%; slight collapse: 30 - 50%; collapse: 50 - 70%; obvious collapse: 70 - 90%; complete collapse: 100%. The test results of the chemical sharpening performance and anti-collapse performance of the toothbrush filaments prepared in each example are as follows:

[0176] Table 1. Test results of the chemical sharpening performance and anti-collapse performance of the toothbrush filaments

[0177]

[0178] It can be seen from the results of the chemical sharpening performance and anti-collapse performance of the examples and comparative examples in Table 1 that the amphiphilic block copolymer prepared by the present invention can effectively improve the compatibility between nylon 12 and PBT to achieve submicron-sized dispersion of PA12 in the PBT matrix. The submicron-sized dispersed PA12 phase can improve the anti-collapse performance of the PBT toothbrush filaments and maintain their chemical sharpening property.

[0179] When no amphiphilic block copolymer is added (Comparative Example 2), PA12 is dispersed in the PBT matrix in large sizes, and the existence of the large-sized phase interface deteriorates the anti-collapse property of the toothbrush filaments.

[0180] When the molecular weight of the amphiphilic block copolymer is too small (Comparative Example 3) or too large (Comparative Example 4), due to the high mismatch between the melt viscosities of the amphiphilic block copolymer and PBT and PA12, the expected compatibilization effect cannot be achieved, the dispersed phase size of PA12 is relatively large, and the corresponding anti-collapse performance of the toothbrush filaments is relatively poor.

[0181] When the addition amount of PA12 is too high (Comparative Example 5), the PBT / PA12 blend system undergoes an inverse phase transition, PA12 is the continuous phase (sea phase), and PBT is the dispersed phase (island phase), and the prepared toothbrush filaments cannot be chemically sharpened with NaOH solution.

[0182] When the molecular weights of the double carboxyl-terminated PBT and double amino-terminated PA12, the raw materials for preparing the amphiphilic block copolymer, are too high, the PBT / PA12 block copolymer will undergo phase separation and deteriorate the compatibilization effect, the dispersed phase size of PA12 is relatively large, and the anti-collapse performance of the toothbrush filaments is poor.

[0183] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the method of the present invention, several improvements and supplements can be made, and these improvements and supplements should also be regarded as the protection scope of the present invention.

Claims

1. An anti-lodging PBT / PA12 sharpened toothbrush filament, by weight, the raw materials comprise the following components: The amphiphilic block copolymer is a block copolymer formed by the amidation reaction of a dicarboxyl-terminated polybutylene terephthalate oligomer and a diamino-terminated nylon 12 oligomer; The number-average molecular weight of the dicarboxyl-terminated polybutylene terephthalate oligomer is 1000 - 3000, and the terminal carboxyl content is 0.65 - 2.0 mmol / g; The number-average molecular weight of the diamino-terminated nylon 12 oligomer is 1000 - 3000, and the terminal amino content is 0.65 - 2.0 mmol / g; The number-average molecular weight of the amphiphilic block copolymer is 10000 - 30000.

2. The anti-lodging PBT / PA12 sharpened toothbrush filaments according to claim 1, wherein Using phenol-1,1,2,2-tetrachloroethane = 1:1 w / w as the solvent, when the concentration is 0.005 g / ml, the relative viscosity of the polybutylene terephthalate is 0.6 - 0.85; using m-cresol as the solvent, when the concentration is 0.005 g / ml, the relative viscosity of the nylon 12 is 1.60 - 1.

90.

3. The anti-toppling PBT / PA12 sharpened toothbrush filaments according to claim 2, wherein The relative viscosity of the polybutylene terephthalate is 0.75; the relative viscosity of the nylon 12 is 1.

80.

4. The lodging-resistant PBT / PA12 sharpened toothbrush filaments according to any one of claims 1-3, characterized in that The preparation method of the amphiphilic block copolymer comprises the following steps: (1) Preparation of the dicarboxyl-terminated polybutylene terephthalate oligomer: (1-1) Under an inert gas atmosphere, terephthalic acid, 1,4-butanediol and catalyst 1 are maintained at 220 - 240 °C for 1 - 3 h for an esterification reaction; maintained at 220 - 240 °C, and purged with nitrogen for 0.5 - 1 h for a prepolymerization reaction; (1-2) After the prepolymerization is completed, catalyst 2 is added, and the reaction is carried out at 240 - 250 °C and an absolute pressure below 100 Pa for 0.5 - 2 h; stop vacuum pumping, supplement inert gas to 50 - 100 kPa, and cool the high-temperature melt by water cooling, dry, and pulverize to prepare the dicarboxyl-terminated PBT oligomer; Catalyst 1 and catalyst 2 are independently selected from one or more of tetrabutyl titanate, tetraisopropyl titanate, and dioctyltin oxide; 2) Preparation of the diamino-terminated nylon 12 oligomer: (2-1) Under an inert gas atmosphere, dodecanolactam, a diamine-based capping agent and water are maintained at 270 - 290 °C for 3 - 7 h to complete the ring-opening reaction of dodecanolactam; (2-2) After the ring-opening is completed, the pressure is released to atmospheric pressure, and the temperature is reduced to 180 - 220 °C while releasing the pressure, and then vacuum treatment is carried out for 30 - 60 min to complete the melt polycondensation; after the melt polycondensation is completed, stop vacuum pumping and protect with an inert gas; (3) Preparation of the amphiphilic block copolymer: Under an inert gas atmosphere, the diamino-terminated nylon 12 oligomer, the dicarboxyl-terminated polybutylene terephthalate oligomer and a molecular weight regulator are reacted at 240 - 250 °C and an absolute pressure below 1 kPa for 30 - 60 min to cause the amidation reaction between the dicarboxyl-terminated PBT oligomer and the diamino-terminated nylon 12 oligomer to obtain a PBT and PA12 block copolymer, which is drawn, water-cooled, pelletized, and dried.

5. The lodging-resistant PBT / PA12 sharpened toothbrush filaments according to claim 4, wherein In the step (3), the molar ratio of the terminal carboxyl groups of the dicarboxyl-terminated polybutylene terephthalate oligomer to the terminal amino groups of the diamino-terminated nylon 12 oligomer is 1:

1.

6. The anti-lodging PBT / PA12 sharpened toothbrush filaments according to claim 1, characterized in that, The number-average molecular weight of the amphiphilic block copolymer is 20,000.

7. The lodging-resistant PBT / PA12 sharpened toothbrush filaments according to claim 1, wherein The antioxidant is selected from one or more of antioxidant 1010, antioxidant 1098, antioxidant 168, and antioxidant H10; the lubricant is selected from one or more of ethylene bisstearamide, oleic acid amide, silicone oil, and paraffin.

8. The lodging-resistant PBT / PA12 sharpened toothbrush filaments according to claim 7, characterized in that, The antioxidant is selected as a 1:1 mass compounding system of antioxidant 1010 and antioxidant 168.

9. The preparation method of the lodging-resistant PBT / PA12 sharpened toothbrush filaments according to any one of claims 1-8, comprising the following steps: (a) Preparation step of PBT / PA12 compounded pellet: Polybutylene terephthalate, nylon 12, amphiphilic block copolymer, lubricant, and antioxidant are added to a high-speed mixer and mixed for 10-20 min to obtain a compounded material. Then, the compounded material is melt-compounded and extruded by a twin-screw extruder, water-cooled, pelletized, dried to prepare PBT / PA12 compounded pellets; (b) Preparation step of the bobbin: The bobbin is prepared by a melt spinning production line. The compounded pellets prepared in step (a) are plasticized by a single-screw extruder, extruded through a spinneret, water-cooled and shaped, hot-stretched, wound on a roll, heat-treated and hardened, and packaged and cut to prepare the bobbin; (c) Sharpened treatment step of the bobbin: The bobbin prepared in step (b) is placed in a bobbin sharpened groove filled with a sharpening liquid for sharpened treatment, washed, and dried to prepare sharpened toothbrush filaments.

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