Marine degradable straw and preparation method thereof

Abstract

The invention discloses a marine degradable straw and a preparation method thereof, the marine degradable straw comprises polyhydroxyalkanoate A, polyhydroxyalkanoate B, polycaprolactone, an inorganic filler, a reactive compatibilizer and an antioxidant, and the weight ratio of the polyhydroxyalkanoate A to the polyhydroxyalkanoate B to the polycaprolactone to the inorganic filler to the reactive compatibilizer to the antioxidant is (40-60): (10-30): (5-20): (10-25): (0.5-1): (0.3-0.5). According to the preparation method provided by the invention, a polycaprolactone chain segment is connected to chain segments of polyhydroxyalkanoate A and polyhydroxyalkanoate B by using a reactive compatilizer, so that the aims of remarkably improving the elongation at break and the impact strength of the straw material and not influencing the marine degradation performance of the straw material are fulfilled; meanwhile, the suction pipe is crystallized in the constant-temperature water tank, the crystallization process is simple, and the heat-resistant temperature of the suction pipe is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of degradable straws and preparation processes, and in particular to a marine degradable straw and a preparation method thereof. Background Art

[0002] Degradable straws are mainly made of polylactic acid (PLA) and polybutylene succinate (PBS). According to the relevant literature "Degradation properties of Typical Biodegradable Polyester in Seawater", the mass loss rate of PLA and PBS materials in the ocean is less than 2% within 365 days. A large amount of plastic waste is discharged into the ocean. Existing degradable materials cannot alleviate the problem of marine environmental pollution. Polyhydroxyalkanoates and polycaprolactone materials have passed the marine degradation certification and can also be degraded under home composting and industrial composting conditions. The straws used in the prior art cannot be degraded by seawater, which aggravates the problem of environmental pollution. Summary of the invention

[0003] Purpose of the invention: The marine degradable straw and its preparation method of the present invention can achieve the purpose of being degradable in seawater, and at the same time solve the problem that the straw does not bend when stirring drinks at high temperature and does not crack at low temperature.

[0004] Technical solution: The present invention proposes a marine degradable straw, which is characterized by comprising polyhydroxyalkanoate A, polyhydroxyalkanoate B, polycaprolactone, an inorganic filler, a reactive compatibilizer and an antioxidant, wherein the weight ratio of each component of polyhydroxyalkanoate A: polyhydroxyalkanoate B: polycaprolactone: inorganic filler: reactive compatibilizer: antioxidant is 40-60:10-30:5-20:10-25:10.5-1:0.3-0.5.

[0005] Preferably, the polyhydroxyalkanoate A and polyhydroxyalkanoate B are one or more of poly 3-hydroxybutyrate, poly 3-hydroxybutyrate-co-3-hydroxyvalerate, poly 3-hydroxybutyrate-co-3-hydroxyhexanoate, and poly 3-hydroxybutyrate-co-4-hydroxybutyrate.

[0006] Preferably, the polyhydroxyalkanoate A and polyhydroxyalkanoate B have a melt index in the range of 1-15 g / 10 min and a number average molecular weight in the range of 300,000 to 350,000 g / mol.

[0007] Preferably, the polycaprolactone has a melt index in the range of 1-10 g / 10 min and a number average molecular weight in the range of 70,000-80,000 g / mol.

[0008] Preferably, the inorganic filler is one or more of talc, mineral powder, magnesium silicate and calcium carbonate.

[0009] Preferably, the reactive compatibilizer is one or more of ADR4370, ADR4468, diphenylmethane diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate.

[0010] Preferably, the antioxidant is one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris[2,4-di-tert-butylphenyl]phosphite, 2,6-di-tert-butyl-p-cresol, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and dilauryl thiodipropionate.

[0011] A method for preparing a marine degradable straw comprises the following steps:

[0012] 1. Mix polyhydroxyalkanoate A, polyhydroxyalkanoate B and polycaprolactone uniformly, add inorganic filler, reactive compatibilizer, antioxidant and the like in sequence under low-speed stirring, and stir uniformly at high speed to obtain a mixture;

[0013] 2. Add the mixture obtained in step 1 into the hopper of the straw forming machine. The mixture is heated to melt, plasticized at high temperature, and extruded into straw embryos. The straw embryos are pulled by a tractor through a constant temperature water tank for crystallization, dehydration, and cutting processes. After cooling, the finished straws are obtained.

[0014] Preferably, in step 1, the low-speed stirring speed is 50-100 r / min, and the high-speed stirring speed is 500-1000 r / min.

[0015] Preferably, in step 2, the temperature of the heating section of the straw forming machine is 150-160°C, the temperature of the plasticizing section is 160-175°C, the die extrusion temperature is 170-175°C, the traction speed of the traction machine is 200mm / s-600mm / s, and the temperature of the constant temperature water tank is maintained at 60-65°C.

[0016] Beneficial effects: The present invention adopts melt blending modification technology, and under the action of a compatibilizer, polyhydroxyalkanoate A with a slow crystallization rate and poor toughness and polycaprolactone with excellent toughness and polyhydroxyalkanoate B with a fast crystallization rate are reactively blended and modified. The polycaprolactone chain segments are linked to the molecular main chains of polyhydroxyalkanoate A and polyhydroxyalkanoate B. The reaction conditions are mild, and the processing technology is simple and fast. The polycaprolactone material has extremely high toughness, giving the straw material a higher elongation at break, which is increased from 2% of the pure material to 10%, thereby ensuring the toughness of the straw product. At the same time, polyhydroxyalkanoate B has a very fast crystallization rate. The melt blending modification technology is used to react and blend the slow crystallization rate and poor toughness polyhydroxyalkanoate A with excellent toughness and the fast crystallization rate polyhydroxyalkanoate B under the action of a compatibilizer. The polycaprolactone chain segment is connected to the main molecular chain of polyhydroxyalkanoate A and polyhydroxyalkanoate B. The reaction conditions are mild, and the processing technology is simple and fast. The polycaprolactone material has extremely high toughness, giving the straw material a higher elongation at break, which is increased from 2% of pure material to 10%, ensuring the toughness of the straw product. At the same time, the crystallization rate of polyhydroxyalkanoate B is very fast, and the half-crystallization time is only 0.3min. The ideal crystallization temperature is around 60°C. A constant temperature water tank is used to implement underwater continuous crystallization, so that the straw can be quickly formed and the material has a high thermal deformation temperature, meeting the purpose of the straw product not bending when stirred above 85°C. At the same time, polyhydroxyalkanoates A, polyhydroxyalkanoates B, and polycaprolactone are not only marine degradable, but also meet the conditions for degradation in household and industrial composting. Compared with PLA and PBS straws on the market, they have obvious advantages in terms of product use and environmental protection. The use of a constant temperature water tank for underwater continuous crystallization allows the straws to be quickly formed and ensures the high thermal deformation temperature of the material, meeting the purpose of the straw product not bending when stirred above 85°C. At the same time, polyhydroxyalkanoates A, polyhydroxyalkanoates B, and polycaprolactone are not only marine degradable, but also meet the conditions for degradation in household and industrial composting. Compared with PLA and PBS straws on the market, they have obvious advantages in terms of product use and environmental protection. DETAILED DESCRIPTION

[0017] The term "marine degradable straw" involved in the present invention means that the straw can be completely decomposed into small molecular substances such as H2O and inorganic salts in a seawater environment.

[0018] The raw materials and their sources involved in the present invention are: poly 3-hydroxybutyrate-co-3-hydroxyhexanoate, produced by Beijing Lansu Co., Ltd.; poly 3-hydroxybutyrate and poly 3-hydroxybutyrate-co-3-hydroxyvalerate, produced by Zhuhai Maidefa Co., Ltd.; poly 3-hydroxybutyrate-co-4-hydroxybutyrate, produced by Beijing Weigou Biotechnology Co., Ltd.; polycaprolactone, produced by Hunan Juren Chemical Co., Ltd.; magnesium silicate, produced by BASF Co., Ltd. of Germany; talc, produced by Suzhou Yiweinan Co., Ltd.; mineral powder, produced by Suzhou Yiweinan Co., Ltd.; ADR4370 and ADR4468, produced by BASF GmbH, Germany; hexamethylene diisocyanate, dilauryl thiodipropionate, isophorone diisocyanate and β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, produced by Shanghai MacLean Co., Ltd.; pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, produced by Shanghai Langyi Functional Materials Co., Ltd.

[0019] The tensile properties of the straw material were tested in accordance with GB / T 528-2009, with a test rate of 5 mm / min. The sample state was conditioned in accordance with GB / T 2918-1998, with a temperature of 23 ± 2 °C and a relative humidity of 50% ± 10%, for a conditioning time of at least 40 h but no more than 96 h. The notched impact strength test was performed using a pendulum impact tester in accordance with GB / T 1043-2006. Example 1

[0020] Weigh 40kg of dried poly 3-hydroxybutyrate-co-3-hydroxyhexanoate, 30kg of poly 3-hydroxybutyrate, and 5kg of polycaprolactone, mix them evenly, add 25kg of magnesium silicate, 0.5kg of ADR4370, and 0.3kg of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] in sequence at a stirring speed of 70r / min, stir at a speed of 1000r / min for 3min, and stir evenly to obtain a mixture. Add the mixture into the hopper of the straw forming machine, heat and melt, high-temperature plasticize, extrude into straw embryos, and the straw embryos are pulled by a tractor at a speed of 500mm / s through a constant temperature water tank for crystallization, dehydration, and cutting, and then cool to obtain a finished straw. The temperature of the heating section of the straw forming machine is 160°C, the temperature of the plasticizing section is 170°C, the extrusion temperature of the die head is 175°C, and the temperature of the constant temperature water tank is maintained at 60°C. At the same time, the prepared mixture is compression molded at a temperature of 170° C., a pressure of 10 MPa, hot pressing for 3 min, cold pressing for 2 min, and cut into corresponding standard mechanical test specimens.

[0021] Example 2

[0022] Weigh 40kg of dried poly 3-hydroxybutyrate-co-3-hydroxyhexanoate, 30kg of poly 3-hydroxybutyrate, and 10kg of polycaprolactone, mix them evenly, add 20kg of magnesium silicate, 0.5kg of ADR4370, and 0.3kg of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] in sequence at a stirring speed of 70r / min, stir at a speed of 1000r / min for 3min, and stir evenly to obtain a mixture. Add the mixture into the hopper of the straw forming machine, heat and melt, high-temperature plasticize, extrude into straw embryos, and the straw embryos are pulled by a tractor at a speed of 500mm / s through a constant temperature water tank for crystallization, dehydration, and cutting, and then cool to obtain a finished straw. The temperature of the heating section of the straw forming machine is 160°C, the temperature of the plasticizing section is 170°C, the extrusion temperature of the die head is 175°C, and the temperature of the constant temperature water tank is maintained at 60°C. At the same time, the prepared mixture is compression molded at a temperature of 170° C., a pressure of 10 MPa, hot pressing for 3 min, cold pressing for 2 min, and cut into corresponding standard mechanical test specimens.

[0023] Example 3

[0024] Weigh 40kg of dried poly 3-hydroxybutyrate-co-3-hydroxyhexanoate, 30kg of poly 3-hydroxybutyrate, and 15kg of polycaprolactone, mix them evenly, add 15kg of magnesium silicate, 0.5kg of ADR4370, and 0.3kg of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] in sequence at a stirring speed of 70r / min, stir at a speed of 1000r / min for 3min, and stir evenly to obtain a mixture. Add the mixture into the hopper of the straw forming machine, heat and melt, high-temperature plasticize, extrude into straw embryos, and the straw embryos are pulled by a tractor at a speed of 500mm / s through a constant temperature water tank for crystallization, dehydration, and cutting, and then cool to obtain a finished straw. The temperature of the heating section of the straw forming machine is 160°C, the temperature of the plasticizing section is 170°C, the extrusion temperature of the die head is 175°C, and the temperature of the constant temperature water tank is maintained at 60°C. At the same time, the prepared mixture is compression molded at a temperature of 170° C., a pressure of 10 MPa, hot pressing for 3 min, cold pressing for 2 min, and cut into corresponding standard mechanical test specimens.

[0025] Example 4

[0026] Weigh 40kg of dried poly 3-hydroxybutyrate-co-3-hydroxyhexanoate, 30kg of poly 3-hydroxybutyrate, and 20kg of polycaprolactone, mix them evenly, add 10kg of magnesium silicate, 0.5kg of ADR4370, and 0.3kg of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] in sequence at a stirring speed of 70r / min, stir at a speed of 1000r / min for 3min, and stir evenly to obtain a mixture. Add the mixture into the hopper of the straw forming machine, heat and melt, high-temperature plasticize, extrude into straw embryos, and the straw embryos are pulled by a tractor at a speed of 500mm / s through a constant temperature water tank for crystallization, dehydration, and cutting, and then cool to obtain a finished straw. The temperature of the heating section of the straw forming machine is 160°C, the temperature of the plasticizing section is 170°C, the extrusion temperature of the die head is 175°C, and the temperature of the constant temperature water tank is maintained at 60°C. At the same time, the prepared mixture is compression molded at a temperature of 170° C., a pressure of 10 MPa, hot pressing for 3 min, cold pressing for 2 min, and cut into corresponding standard mechanical test specimens.

[0027] Example 5

[0028] Weigh 50kg of dried poly 3-hydroxybutyrate-co-3-hydroxyhexanoate, 20kg of poly 3-hydroxybutyrate, and 15kg of polycaprolactone, mix them evenly, add 15kg of magnesium silicate, 0.5kg of ADR4370, and 0.3kg of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] in sequence at a stirring speed of 70r / min, stir at a speed of 1000r / min for 3min, and stir evenly to obtain a mixture. Add the mixture into the hopper of the straw forming machine, heat and melt, high-temperature plasticize, extrude into straw embryos, and the straw embryos are pulled by a tractor at a speed of 500mm / s through a constant temperature water tank for crystallization, dehydration, and cutting, and then cool to obtain a finished straw. The temperature of the heating section of the straw forming machine is 160°C, the temperature of the plasticizing section is 170°C, the extrusion temperature of the die head is 175°C, and the temperature of the constant temperature water tank is maintained at 60°C. At the same time, the prepared mixture is compression molded at a temperature of 170° C., a pressure of 10 MPa, hot pressing for 3 min, cold pressing for 2 min, and cut into corresponding standard mechanical test specimens.

[0029] Example 6

[0030] Weigh 60kg of dried poly 3-hydroxybutyrate-co-3-hydroxyhexanoate, 10kg of poly 3-hydroxybutyrate, and 15kg of polycaprolactone, mix them evenly, add 15kg of magnesium silicate, 0.5kg of ADR4370, and 0.3kg of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] in sequence at a stirring speed of 70r / min, stir at a speed of 1000r / min for 3min, and stir evenly to obtain a mixture. Add the mixture into the hopper of the straw forming machine, heat and melt, high-temperature plasticize, extrude into straw embryos, and the straw embryos are pulled by a tractor at a speed of 500mm / s through a constant temperature water tank for crystallization, dehydration, and cutting, and then cool to obtain a finished straw. The temperature of the heating section of the straw forming machine is 160°C, the temperature of the plasticizing section is 170°C, the die extrusion temperature is 175°C, and the temperature of the constant temperature water tank is maintained at 60°C. At the same time, the prepared mixture is compression molded at a temperature of 170° C., a pressure of 10 MPa, hot pressing for 3 min, cold pressing for 2 min, and cut into corresponding standard mechanical test specimens.

[0031] Example 7

[0032] Weigh 40kg of dried poly 3-hydroxybutyrate-co-3-hydroxyhexanoate, 30kg of poly 3-hydroxybutyrate, and 15kg of polycaprolactone, mix them evenly, add 15kg of magnesium silicate, 1kg of ADR4370, and 0.5kg of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] in sequence at a stirring speed of 70r / min, stir at a speed of 1000r / min for 3min, and stir evenly to obtain a mixture. Add the mixture into the hopper of the straw forming machine, heat and melt, high-temperature plasticize, extrude into straw embryos, and the straw embryos are pulled by a tractor at a speed of 500mm / s through a constant temperature water tank for crystallization, dehydration, and cutting, and then cool to obtain a finished straw. The temperature of the heating section of the straw forming machine is 160°C, the temperature of the plasticizing section is 170°C, the extrusion temperature of the die head is 175°C, and the temperature of the constant temperature water tank is maintained at 60°C. At the same time, the prepared mixture is compression molded at a temperature of 170° C., a pressure of 10 MPa, hot pressing for 3 min, cold pressing for 2 min, and cut into corresponding standard mechanical test specimens.

[0033] Example 8

[0034] Weigh 40 kg of dried poly 3-hydroxybutyrate-co-4-hydroxybutyrate and poly 3-hydroxybutyrate-co-3-

[0035] 30kg of hydroxyvalerate and 20kg of polycaprolactone are mixed evenly, and 10kg of magnesium silicate, 0.5kg of ADR4370 and 0.3kg of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate are added in sequence at a stirring speed of 70r / min, and stirred at a speed of 1000r / min for 3min to obtain a mixture evenly. The mixture is added to the hopper of the straw forming machine, and the mixture is heated, melted, plasticized at high temperature, extruded into straw embryos, and the straw embryos are pulled by a tractor at a speed of 500mm / s through a constant temperature water tank for crystallization, dehydration, and cutting, and the finished straws are obtained after cooling. The temperature of the heating section of the straw forming machine is 160°C, the temperature of the plasticizing section is 170°C, the extrusion temperature of the die head is 175°C, and the temperature of the constant temperature water tank is maintained at 60°C. At the same time, the prepared mixture is compression molded at a temperature of 170° C., a pressure of 10 MPa, hot pressing for 3 min, cold pressing for 2 min, and cut into corresponding standard mechanical test specimens.

[0036] Example 9

[0037] Weigh 40kg of dried poly 3-hydroxybutyrate-co-4-hydroxybutyrate, 30kg of poly 3-hydroxybutyrate, and 20kg of polycaprolactone, mix them evenly, add 10kg of magnesium silicate, 0.5kg of ADR4370, and 0.3kg of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] in sequence at a stirring speed of 70r / min, stir at a speed of 1000r / min for 3min, and stir evenly to obtain a mixture. Add the mixture into the hopper of the straw forming machine, heat and melt, high-temperature plasticize, extrude into straw embryos, and the straw embryos are pulled by a tractor at a speed of 500mm / s through a constant temperature water tank for crystallization, dehydration, and cutting, and then cool to obtain a finished straw. The temperature of the heating section of the straw forming machine is 160°C, the temperature of the plasticizing section is 170°C, the extrusion temperature of the die head is 175°C, and the temperature of the constant temperature water tank is maintained at 60°C. At the same time, the prepared mixture is compression molded at a temperature of 170° C., a pressure of 10 MPa, hot pressing for 3 min, cold pressing for 2 min, and cut into corresponding standard mechanical test specimens.

[0038] Example 10

[0039] Weigh 40 kg of dried poly 3-hydroxybutyrate-co-4-hydroxybutyrate and poly 3-hydroxybutyrate-co-3-

[0040] 30kg of hydroxycaproic acid ester and 20kg of polycaprolactone are mixed evenly, and 10kg of magnesium silicate, 0.5kg of ADR4370 and 0.3kg of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate are added in sequence at a stirring speed of 70r / min, and stirred at a speed of 1000r / min for 3min to obtain a mixture evenly. The mixture is added to the hopper of the straw forming machine, and the mixture is heated, melted, plasticized at high temperature, extruded into straw embryos, and the straw embryos are pulled by a tractor at a speed of 500mm / s through a constant temperature water tank for crystallization, dehydration, and cutting, and the finished straws are obtained after cooling. The temperature of the heating section of the straw forming machine is 160℃, the temperature of the plasticizing section is 170℃, the extrusion temperature of the die head is 175℃, and the temperature of the constant temperature water tank is maintained at 60℃. At the same time, the prepared mixture is compression molded at a temperature of 170° C., a pressure of 10 MPa, hot pressing for 3 min, cold pressing for 2 min, and cut into corresponding standard mechanical test specimens.

[0041] Embodiment 11

[0042] Weigh 40kg of dried poly 3-hydroxybutyrate-co-3-hydroxyhexanoate, 30kg of poly 3-hydroxybutyrate, and 20kg of polycaprolactone, mix them evenly, add 10kg of talcum powder, 0.5kg of ADR4468, and 0.3kg of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate at a stirring speed of 70r / min, stir at a speed of 1000r / min for 3min, and stir evenly to obtain a mixture. Add the mixture into the hopper of the straw forming machine, heat and melt, high-temperature plasticize, extrude into straw embryos, and the straw embryos are pulled by a tractor at a speed of 500mm / s through a constant temperature water tank for crystallization, dehydration, and cutting. After cooling, the finished straws are obtained. The temperature of the heating section of the straw forming machine is 160°C, the temperature of the plasticizing section is 170°C, the die extrusion temperature is 175°C, and the temperature of the constant temperature water tank is maintained at 60°C. At the same time, the prepared mixture is compression molded at a temperature of 170° C., a pressure of 10 MPa, hot pressing for 3 min, cold pressing for 2 min, and cut into corresponding standard mechanical test specimens.

[0043] Example 12

[0044] Weigh 40kg of dried poly 3-hydroxybutyrate-co-3-hydroxyhexanoate, 30kg of poly 3-hydroxybutyrate, and 20kg of polycaprolactone, mix them evenly, add 10kg of talcum powder, 0.5kg of hexamethylene diisocyanate, and 0.3kg of dilauryl thiodipropionate in sequence at a stirring speed of 70r / min, stir at a speed of 1000r / min for 3min, and stir evenly to obtain a mixture. Add the mixture into the hopper of the straw forming machine, heat and melt, high-temperature plasticize, extrude into straw embryos, and the straw embryos are pulled by a tractor at a speed of 500mm / s through a constant temperature water tank for crystallization, dehydration, and cutting, and then cool to obtain a finished straw. The temperature of the heating section of the straw forming machine is 160°C, the temperature of the plasticizing section is 170°C, the die extrusion temperature is 175°C, and the temperature of the constant temperature water tank is maintained at 60°C. At the same time, the prepared mixture is compression molded at a temperature of 170° C., a pressure of 10 MPa, hot pressing for 3 min, cold pressing for 2 min, and cut into corresponding standard mechanical test specimens.

[0045] Embodiment 13

[0046] Weigh 40kg of dried poly 3-hydroxybutyrate-co-3-hydroxyhexanoate, 30kg of poly 3-hydroxybutyrate, and 20kg of polycaprolactone, mix them evenly, add 10kg of mineral powder, 0.5kg of isophorone diisocyanate, and 0.3kg of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate at a stirring speed of 70r / min, stir at a speed of 1000r / min for 3min, and stir evenly to obtain a mixture. Add the mixture into the hopper of the straw forming machine, heat and melt, high-temperature plasticize, extrude into straw embryos, and the straw embryos are pulled by a tractor at a speed of 500mm / s through a constant temperature water tank for crystallization, dehydration, and cutting. After cooling, the finished straws are obtained. The temperature of the heating section of the straw forming machine is 160℃, the temperature of the plasticizing section is 170℃, the extrusion temperature of the die head is 175℃, and the temperature of the constant temperature water tank is maintained at 60℃. At the same time, the prepared mixture is compression molded at a temperature of 170° C., a pressure of 10 MPa, hot pressing for 3 min, cold pressing for 2 min, and cut into corresponding standard mechanical test specimens.

[0047] Comparative Example 1

[0048] The straw of this comparative example comprises the following components by weight:

[0049] PLA is 50 parts; PBS is 38 parts; PBAT is 2 parts; TEC is 1 part; talc is 10 parts; antioxidant 168 is 0.1 parts; antioxidant 1010 is 0.4 parts; erucamide is 0.4 parts; EBS is 0.4 parts.

[0050] The preparation method of the comparative example straw comprises the following steps:

[0051] PLA, PBS and PBAT were mixed, and TEC, talcum powder, antioxidant 168, antioxidant 1010, erucic acid amide and EBS were added in sequence under stirring conditions. The mixture was mixed at 1000r / min for 40s using a high-speed mixer, and stirred evenly to form a mixture; the mixture was added to the extrusion equipment, and the straw embryos were obtained through melting, mixing and extrusion. The extrusion temperature of the straw embryos was 180°C, and the temperature of the extruder head was 200°C; the straw embryos were drawn by the traction equipment and passed through water cooling, air cooling, dehydration, cutting and crystallization processes in sequence, and the straws were obtained after cooling. Among them, the traction speed was 0.8m / s, the water cooling temperature was controlled at 35°C, and the crystallization process was as follows: the straw embryos were added to the crystallization tunnel furnace for "annealing" crystallization under the conditions of crystallization temperature of 85°C and crystallization time of 2min, and the straws were obtained after cooling.

[0052] Comparative Example 2

[0053] A method for preparing a highly hydrophobic starch-based straw comprises the following steps: (1) mixing raw materials and auxiliary materials: adding corn starch, octenyl succinic anhydride (accounting for 6% of the amount of corn starch added), SiO2 (accounting for 3% of the amount of corn starch added) and NaOH dissolved in distilled water (accounting for 0.008% of the amount of corn starch added) into a high-speed mixer, mixing evenly, adding water (accounting for 32% of the amount of corn starch added) from an auxiliary valve, stirring at a speed of 100 rpm for 15 minutes; after mixing evenly, bagging, and standing; (2) extruding and constructing octenyl succinic acid starch-based straws: uniformly adding the material obtained in step (1) into a twin-screw extruder through a feeder, and setting the screw speed of the extruder to 150 rpm m, the temperature of the first to fourth zones of the extrusion chamber barrel is set to 50°C, 60°C, 110°C, and 100°C, and the material is extruded through a straw forming extrusion die to form a tube embryo; (3) Cutting treatment: the tube embryo obtained in step (2) is cooled by a conveying device (with a built-in fan), and after cooling, it is cut by a cutting machine; (4) C6H19NSi2 steam hydrophobic modification: the cut straws in step (3) are placed in a sealed container containing sufficient C6H19NSi2 solution, the sealed container is placed in a 52°C drying oven, and the inner and outer surfaces of the straws are sprayed with C6H19NSi2 steam for 75 minutes. After the reaction, it is cooled to room temperature to obtain highly hydrophobic starch-based straws.

[0054] The test results of various properties of the materials of Examples 1-13 and Comparative Examples 1-2 are as follows:

[0055]

[0056] The above is a detailed introduction to a marine degradable, high-toughness, high-temperature-resistant straw and its preparation method provided by the present invention, and the mechanical properties of the straw material are tested and compared with competing products. It can be seen from Examples 1-4 that when the amount of polycaprolactone added increases, the tensile strength of the straw material decreases, but the elongation at break is greatly improved. When the amount of polycaprolactone added reaches 20%, the elongation at break of the straw material is increased from the original 1.9% to 10.9%, and the toughness of the straw material is greatly improved, meeting the use requirements of the straw product under low temperature conditions. Compared with Examples 3 and 7, when the amount of compatibilizer and antioxidant added increases, the toughness and heat deformation temperature of the straw material are less affected. It can be seen from Examples 1-7 that the heat deformation temperature of the material is above 95°C. This is because the crystallization rate of poly 3-hydroxybutyrate is fast. At the ideal crystallization temperature, the straw can be quickly shaped and can meet the requirements of high temperature resistance. Compared with Example 4, Examples 8-10 show that the crystallization rate of poly 3-hydroxybutyrate-co-3-hydroxyvalerate and poly 3-hydroxybutyrate-co-4-hydroxybutyrate is slower than that of poly 3-hydroxybutyrate, so the material of Example 4 shows better mechanical and thermodynamic properties. Compared with Example 4, Examples 11-13 show that ADR4370 has a high degree of functionality and high reactivity of epoxy groups, so the material of Example 4 shows higher tensile strength and elongation at break. And magnesium silicate has a smaller particle size than mineral powder and talcum powder, and the nucleation effect is better, so the heat deformation temperature of material 4 is better. Compared with Comparative Examples 1 and 2, the toughness and high temperature resistance of the patented product are better. At the same time, the straw product of this patent can be degraded under marine conditions while meeting the conditions of home composting and industrial composting degradation of Comparative Example 1. And the production process of the patented straw is simple, low cost, and has broad application prospects.

Claims

1. A marine degradable straw, characterized in that: The invention comprises polyhydroxyalkanoate A, polyhydroxyalkanoate B, polycaprolactone, inorganic filler, reactive compatibilizer and antioxidant, wherein the weight ratio of polyhydroxyalkanoate A: polyhydroxyalkanoate B: polycaprolactone: inorganic filler: reactive compatibilizer: antioxidant is 40-60: 10-30: 5-20: 10-25: 0.5-1: 0.3-0.

5.

2. The marine degradable straw according to claim 1, characterized in that: The polyhydroxyalkanoate A and polyhydroxyalkanoate B are one or more of poly 3-hydroxybutyrate, poly 3-hydroxybutyrate-co-3-hydroxyvalerate, poly 3-hydroxybutyrate-co-3-hydroxyhexanoate, and poly 3-hydroxybutyrate-co-4-hydroxybutyrate.

3. The marine degradable high-toughness and high-temperature-resistant straw according to claim 1, characterized in that: The polyhydroxyalkanoate A and polyhydroxyalkanoate B have a melt index range of 1-15 g / 10 min and a number average molecular weight range of 300,000-350,000 g / mol.

4. The marine degradable straw according to claim 1, characterized in that: The polycaprolactone has a melt index range of 1-10 g / 10 min and a number average molecular weight range of 70,000-80,000 g / mol.

5. The marine degradable straw according to claim 1, characterized in that: The inorganic filler is one or more of talc, mineral powder, magnesium silicate and calcium carbonate.

6. The marine degradable straw according to claim 1, characterized in that: The reactive compatibilizer is one or more of ADR4370, ADR4468, diphenylmethane diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate.

7. The marine degradable straw according to claim 1, characterized in that: The antioxidant is one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris[2,4-di-tert-butylphenyl]phosphite, 2,6-di-tert-butyl-p-cresol, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and dilauryl thiodipropionate.

8. A method for preparing a marine degradable straw according to any one of claims 1 to 7, characterized in that: The steps include:

1. Mix polyhydroxyalkanoate A, polyhydroxyalkanoate B and polycaprolactone uniformly, add inorganic filler, reactive compatibilizer, antioxidant and the like in sequence under low-speed stirring, and stir uniformly at high speed to obtain a mixture; 2. Add the mixture obtained in step 1 into the hopper of the straw forming machine. The mixture is heated to melt, plasticized at high temperature, and extruded into straw embryos. The straw embryos are pulled by a tractor through a constant temperature water tank for crystallization, dehydration, and cutting processes. After cooling, the finished straws are obtained.

9. The method for preparing marine degradable straws according to claim 8, characterized in that: In step 1, the low-speed stirring speed is 50-100 r / min, and the high-speed stirring speed is 500-1000 r / min.

10. The method for preparing marine degradable straws according to claim 8, characterized in that: In step 2, the temperature of the heating section of the straw forming machine is 150-160°C, the temperature of the plasticizing section is 160-175°C, the die extrusion temperature is 170-175°C, the traction speed of the traction machine is 200mm / s-600mm / s, and the temperature of the constant temperature water tank is maintained at 60-65°C.

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