CN103951919B - Polyvinyl alcohol composite master batch and preparation method thereof - Google Patents

Abstract

The invention discloses a polyvinyl alcohol composite masterbatch and a preparation method thereof. The polyvinyl alcohol composite masterbatch is a blend, and the blend includes polyvinyl alcohol and polyhydroxyalkanoate; the weight content of polyvinyl alcohol is 51-99%, and the weight content of polyhydroxyalkanoate is 1-49%. . The method is to mix polyvinyl alcohol powder and polyhydroxyalkanoate powder evenly, then add deionized water and mix evenly to obtain a mixture; after the mixture is dried, it is injected into a screw extruder with a heating device, at 175-185 ^o Melt at C for 4-8 minutes, melt and extrude and cool down to room temperature naturally, and pelletize with a granulator. The material is a new type of environmentally friendly material, which can be naturally degraded after being used and discarded, and does not cause a burden to the environment; it has a significantly reduced melt viscosity in a relatively low temperature range and a wide shear rate range, and has excellent properties. thermoplastic processing characteristics.

Description

A kind of polyvinyl alcohol composite masterbatch and preparation method thereof

technical field

The invention belongs to the field of polymer materials, and in particular relates to a polyvinyl alcohol composite masterbatch and a preparation method thereof.

Background technique

Polyvinyl alcohol (PVA) is a water-soluble biodegradable polymer with excellent mechanical, physical, chemical properties and film-forming properties. It is widely used in the fields of films, fibers, adhesives, and papermaking additives. However, the PVA main chain contains a large number of hydroxyl groups, and a large number of hydrogen bonds are formed between and within the molecules, making its melting point close to the decomposition temperature, making it difficult to perform conventional thermoplastic processing. However, conventional solution wet forming, such as solution casting into film, needs to go through the process of dissolving and drying the resin, which has the disadvantages of complex process, high cost, low yield, and large amount of wastewater discharge. Although my country is a big country in the production and consumption of PVA products, the production process of PVA is still dominated by traditional solution processing, which is not conducive to industrial development. Therefore, it is of great significance to realize the thermoplastic processing of PVA.

At present, the known method for realizing PVA thermoplastic processing is to add water, alcohols, caprolactam and other small molecular substances to reduce the melting point and shear viscosity of PVA through plasticization. For example, in the literature [Polymer Science and Engineering, 2008, 24 (5): 84-87], glycerin, polyethylene glycol, caprolactam, etc. are made into a compound plasticizing system, and dissolved in water with PVA to make PVA-plasticizing The system can effectively reduce the melt index, reduce the melting point of PVA, increase the thermal decomposition temperature, and improve the appearance of the product. The Chinese invention patent with publication number 10313698A proposes a compound plasticizer formula and processing technology for PVA thermoplastic processing, so as to realize the thermoplastic processing of PVA. However, small organic molecule plasticizers are volatile and precipitate out of the product at higher processing temperatures, thereby affecting the performance of the product. As reported in the literature [China Plastics, 2003, 17 (2): 60-62] in the PVA system plasticized by alcohol amine modifiers, the plasticizing performance of PVA becomes worse with the increase of PVA alcoholysis degree. The literature [Plastic Industry, 2002, 30 (1): 32-34] studies on PVA plasticization shows that the amide organic small molecules used to plasticize PVA have the problem of easy precipitation after long-term storage. The Chinese patent whose publication number is CN102391598A reports a production method of polyvinyl alcohol material. Its technical characteristics are to plasticize PVA with a plasticizer in the presence of water, and to carry out hot melting at a temperature lower than the decomposition temperature of polyvinyl alcohol. Processing, but water is easy to volatilize at higher temperatures, and often produces air bubbles during processing, which cannot achieve smooth and continuous production.

Obviously, the thermoplastic processing of PVA is a technical difficulty and research hotspot in this technical field. The currently known technologies all plasticize PVA by adding small molecular substances such as water and glycerin, which leads to problems such as plasticizer residue and precipitation, as well as bubbles and defects during thermoplastic processing. Therefore, it is urgent to develop new technologies to realize the thermoplastic processing of PVA and avoid various problems caused by small molecule plasticization.

Contents of the invention

An object of the present invention is to provide a polyvinyl alcohol composite masterbatch for the deficiencies of the prior art.

The polyvinyl alcohol composite masterbatch of the present invention is a blend, and the blend includes polyvinyl alcohol and polyhydroxyalkanoate; wherein the weight content of polyvinyl alcohol is 51% to 99%, and the weight content of polyhydroxyalkanoate The apparent shear viscosity of polyvinyl alcohol composite masterbatch is lower than 20000Pa·s under the conditions of 175～185℃ and 100s ^-1 shear rate, and has good thermoplastic processing performance;

Preferably, the weight content of polyvinyl alcohol in the polyvinyl alcohol composite masterbatch is 60-90%, the weight content of polyhydroxyalkanoate is 10-40%, under the conditions of 175-185°C and 100s ^-1 shear rate The apparent shear viscosity of the lower polyvinyl alcohol composite masterbatch is lower than 10000Pa·s, which has good thermoplastic processing performance.

Another object of the present invention is to provide a preparation method of the above-mentioned polyvinyl alcohol composite masterbatch.

The inventive method comprises the following steps:

Step (1). The polyvinyl alcohol powder and the polyhydroxyalkanoate powder are physically mixed for the first time, and then deionized water is added for the second physical mixing, and the mixture is obtained after mixing; wherein the polyvinyl alcohol powder is mixed with the polyhydroxyalkanoate powder The weight ratio of polyhydroxyalkanoate powder is 51:49-99:1, and the weight of deionized water is 0.5-1.5% of the total weight of polyvinyl alcohol powder and polyhydroxyalkanoate powder;

Preferably, the weight ratio of polyvinyl alcohol powder to polyhydroxyalkanoate powder is 6:4 to 9:1;

The number-average particle diameter of the polyvinyl alcohol powder is 0.01-0.1mm, the average degree of polymerization is 600-1800, and the degree of alcoholysis is 88%-99.8% (mol/mol);

Preferably, the polyvinyl alcohol powder has a number-average particle diameter of 0.01-0.055mm, an average degree of polymerization of 600-1000, and a degree of alcoholysis of 88%-99.8% (mol/mol);

The number-average particle diameter of the polyhydroxyalkanoate powder is 0.01-0.1 mm, and has the following general chemical structure formula:

In the formula: R ₁ and R ₂ are independently H, methyl CH ₃ or ethyl C ₂ H ₅ ; m1 and m2 are independently 1 or 2; x and y are independently 0 or any natural number from 200 to 20000, And x, y are not 0 at the same time.

Preferably, in the general chemical formula of the polyhydroxyalkanoate powder, R ₁ is methyl CH ₃ , m1 is 1, x is any natural number from 200 to 20000, and when y is 0, it is poly-3-hydroxybutyric acid Ester (P-3HB), the number-average particle diameter is 0.01-0.1 mm, the volume crystallinity is 30-70%, and the weight-average molecular weight is 90,000-650,000;

As a preference, the polyhydroxyalkanoate powder in the general formula is poly ₄ -hydroxybutyrate (P-4HB ), the number-average particle diameter is 0.01-0.1 mm, the volume crystallinity is 30-70%, and the weight-average molecular weight is 90,000-650,000;

Preferably, when the polyhydroxyalkanoate powder is in the general formula, R ₁ is ethyl C ₂ H ₅ , m1 is 1, x is any natural number from 200 to 20000, and y is 0, it is poly-3-hydroxyvaleric acid Ester (P-3HV), the number-average particle diameter is 0.01-0.1 mm, the volume crystallinity is 15-55%, and the weight-average molecular weight is 90,000-650,000;

Preferably, when the polyhydroxyalkanoate powder is in the general formula, when R ₁ is methyl CH ₃ , R ₂ is H, m1 is 1, m2 is 2, and x and y are any natural numbers ranging from 200 to 20000, it is Poly 3-hydroxybutyric acid-4-hydroxybutyric acid copolyester (P-3HB-4HB), its number average particle diameter is 0.01~0.1mm, volume crystallinity is 10~50%, weight average molecular weight is 9~75 10,000, the molar content of 4-hydroxybutyrate (P-4HB) is 1-45%;

Preferably, the polyhydroxyalkanoate powder has a general formula in which R ₁ is methyl CH ₃ , R ₂ is ethyl C ₂ H ₅ , m1 and m2 are both 1, and x and y are both 200 to 20000. Any natural number is polyhydroxybutyrate-valeric acid copolyester (PHBV), its number-average particle diameter is 0.01-0.1mm, volume crystallinity is 15-65%, weight-average molecular weight is 9-750,000, of which 3 The molar content of -hydroxyvalerate (P-3HV) is 1-45%;

Step (2). Vacuum-dry the mixture obtained in step (1) at 60-100° C. until the constant weight remains unchanged, and remove excess water;

Step (3). Inject the dried mixture of step (2) into a screw extruder with a heating device. The length-to-diameter ratio of the screw is 10-30, melted at 175-185°C for 4-8 minutes, and melt-extruded Get extruded melt;

Step (4). The extruded melt in step (3) is naturally cooled to normal temperature in the air, and pelletized by a granulator to prepare a granular polyvinyl alcohol composite masterbatch that can be used for thermoplastic processing.

The polyvinyl alcohol composite masterbatch of the present invention contains both biodegradable polyvinyl alcohol and polyhydroxyalkanoate components, is a new environment-friendly material, can be naturally degraded after being used and discarded, and does not cause a burden to the environment. The polyvinyl alcohol composite masterbatch has a significantly reduced melt viscosity in a relatively low temperature range and a wide shear rate range, and has excellent thermoplastic processing characteristics. Through a large number of experiments, the present invention finds that only when the structural parameters (particle size, average degree of polymerization, degree of alcoholysis, chemical structure, molecular weight, crystallinity, and comonomer content) of polyvinyl alcohol and polyhydroxyalkanoate meet specific conditions, The two can have moderate hydroxyl interaction, so that the original hydrogen bond of polyvinyl alcohol is weakened, and at the same time, the dispersed phase of polyhydroxyalkanoate is deformed and oriented, thereby reducing the melt viscosity of the composite system. The polyvinyl alcohol composite masterbatch avoids the addition of small molecular substances such as water and glycerin in the conventional method to realize the thermoplastic processing of polyvinyl alcohol, and solves the problems of small molecular substances such as bubbles generated during processing and precipitation during use, which is helpful It is used to improve the appearance uniformity and performance stability of the product. The present invention also proposes a preparation method for the above-mentioned polyvinyl alcohol composite masterbatch. The polyvinyl alcohol powder and the polyhydroxyalkanoate powder are uniformly dispersed through the first physical mixing; and then an appropriate amount of water is added through the second physical mixing to make the polyvinyl alcohol Shallow dissolution occurs on the surface of the vinyl alcohol powder, which increases the adhesion between the polyvinyl alcohol powder and the polyhydroxyalkanoate powder; then the temperature and time window of melt extrusion are controlled to ensure the uniform dispersion of the composite system while effectively avoiding polymerization. Thermal degradation of vinyl alcohol.

detailed description

The technical solutions and effects of the present invention will be further described below in conjunction with the embodiments. The apparent shear viscosity of the polyvinyl alcohol composite masterbatch in the examples was measured by a capillary rheometer modeled as GOTTFERT ^TM , RHEO-TESTER2000. The apparent shear viscosity of the polyvinyl alcohol powder in the examples is higher than 20,000 Pa·s in the temperature range of 175-185° C. and at a shear rate of 100 s ⁻¹ , and cannot be melt-extruded smoothly.

Example 1:

Take 90 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.01mm, an average degree of polymerization of 600, and a degree of alcoholysis of 88% (mol/mol), and a number-average particle diameter of 0.01mm, a volume crystallinity of 70%, and a weight 10 kg of poly-3-hydroxybutyrate (P-3HB) powder with an average molecular weight of 90,000 was physically mixed for the first time in a high-speed mixer at room temperature for 3 to 5 minutes; then 1.5 kg of water was added, Carry out the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; the mixed material is vacuum-dried at 100°C for 6 hours to remove excess water; the dried mixed material is injected into a unit with a screw aspect ratio of 30 In the screw extruder, melt and extrude at 175°C, adjust the screw speed to make the melting time of the mixture 8 minutes; naturally cool the extruded melt in the air, and cut into pellets with a granulator to prepare milky white, smooth surface Granular polyvinyl alcohol composite masterbatch. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 175°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 9520, 3730, and 510 Pa·s, respectively, and have good thermoplastic processing properties. performance.

Example 2:

Take 75 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.0325mm, an average degree of polymerization of 800, and a degree of alcoholysis of 93.9% (mol/mol), and a number-average particle diameter of 0.0325mm, a volume crystallinity of 50%, and a weight 25 kg of poly-3-hydroxybutyrate (P-3HB) powder with an average molecular weight of 370,000 was physically mixed for the first time in a high-speed mixer at room temperature for 3 to 5 minutes; then 1 kg of water was added, Carry out the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; the mixed material is vacuum-dried at 80°C for 6 hours to remove excess water; the dried mixed material is injected into a unit with a screw aspect ratio of 20 In the screw extruder, melt and extrude at 180°C, adjust the screw speed so that the melting time of the mixture is 4 minutes; cool the extruded melt naturally in the air, and cut into pellets with a granulator to prepare milky white, smooth surface Granular polyvinyl alcohol composite masterbatch. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 180°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 9600, 3980, and 530 Pa·s, respectively, and have good thermoplastic processing properties. performance.

Example 3:

Take 60 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.055mm, an average degree of polymerization of 1000, and a degree of alcoholysis of 99.8% (mol/mol), and a number-average particle diameter of 0.055mm, a volume crystallinity of 30%, and a weight 40 kg of poly-3-hydroxybutyrate (P-3HB) powder with an average molecular weight of 650,000 was physically mixed for the first time in a high-speed mixer at room temperature for 3 to 5 minutes; then 0.5 kg of water was added, Carry out the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; the mixture is vacuum-dried at 60°C for 8 hours to remove excess water; the dried mixture is injected into a cone with a screw length-to-diameter ratio of 10 In a twin-screw extruder, melt and extrude at 185 ° C, adjust the screw speed to make the melting time of the mixture 6 minutes; naturally cool the extruded melt in the air, and pelletize with a granulator to prepare milky white, Granular polyvinyl alcohol compound masterbatch with smooth surface. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 185°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 9850, 4160, and 550 Pa·s, respectively, and have good thermoplastic processing properties. performance.

Example 4:

Take 60 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.0325mm, an average degree of polymerization of 600, and a degree of alcoholysis of 93.9% (mol/mol), and a number-average particle diameter of 0.055mm, a volume crystallinity of 70%, and a weight 40 kg of poly-4-hydroxybutyrate (P-4HB) powder with an average molecular weight of 370,000 was physically mixed for the first time in a high-speed mixer at room temperature for 3 to 5 minutes; then 0.5 kg of water was added, Carry out the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; the mixed material is vacuum-dried at 80°C for 6 hours to remove excess water; the dried mixed material is injected into a unit with a screw aspect ratio of 30 In the screw extruder, melt and extrude at 175°C, adjust the screw speed to make the melting time of the mixture 6 minutes; cool the extruded melt naturally in the air, and cut into pellets with a granulator to prepare milky white and smooth surface Granular polyvinyl alcohol composite masterbatch. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 175°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 8400, 2550, and 405 Pa·s, respectively, and have good thermoplastic processing properties. performance.

Example 5:

Take 90 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.01mm, an average degree of polymerization of 800, and a degree of alcoholysis of 99.8% (mol/mol), and a number-average particle diameter of 0.01mm, a volume crystallinity of 50%, and a weight 10 kg of poly-4-hydroxybutyrate (P-4HB) powder with an average molecular weight of 90,000 is physically mixed for the first time in a high-speed mixer, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; then add 1.5 kg of water, Carry out the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; the mixture is vacuum-dried at 100°C for 6 hours to remove excess water; the dried mixture is injected into a cone with a screw length-to-diameter ratio of 10 In a twin-screw extruder, melt and extrude at 185°C, adjust the screw speed so that the melting time of the mixture is 8 minutes; the extruded melt is naturally cooled in the air, and pelletized by a granulator to prepare milky white, Granular polyvinyl alcohol compound masterbatch with smooth surface. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 185°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 9650, 4110, and 560 Pa·s, respectively, and have good thermoplastic processing properties. performance.

Embodiment 6:

Take 75 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.055mm, an average degree of polymerization of 1000, and a degree of alcoholysis of 88% (mol/mol), and a number-average particle diameter of 0.0325mm, a volume crystallinity of 30%, and a weight 25 kg of poly-4-hydroxybutyrate (P-4HB) powder with an average molecular weight of 650,000 was physically mixed for the first time in a high-speed mixer at room temperature for 3 to 5 minutes; then 1 kg of water was added, Carry out the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; the mixed material is vacuum-dried at 60°C for 10 hours to remove excess water; the dried mixed material is injected into a unit with a screw aspect ratio of 20 In the screw extruder, melt and extrude at 180°C, adjust the screw speed so that the melting time of the mixture is 4 minutes; cool the extruded melt naturally in the air, and cut into pellets with a granulator to prepare milky white, smooth surface Granular polyvinyl alcohol composite masterbatch. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 180°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 9800, 4230, and 575 Pa·s, respectively, and have good thermoplastic processing properties. performance.

Embodiment 7:

Take 60 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.055mm, an average degree of polymerization of 600, and a degree of alcoholysis of 99.8% (mol/mol), and a number-average particle diameter of 0.055mm, a volume crystallinity of 15%, and a weight 40 kg of poly-3-hydroxyvalerate (P-3HV) powder with an average molecular weight of 90,000 was physically mixed for the first time in a high-speed mixer at room temperature for 3 to 5 minutes; then 0.5 kg of water was added, Carry out the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; the mixed material is vacuum-dried at 60°C for 8 hours to remove excess water; the dried mixed material is injected into a unit with a screw aspect ratio of 30 In the screw extruder, melt and extrude at 175°C, adjust the screw speed so that the melting time of the mixture is 4 minutes; naturally cool the extruded melt in the air, and cut into pellets with a granulator to prepare milky white, smooth surface Granular polyvinyl alcohol composite masterbatch. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 175°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 7420, 2300, and 382 Pa·s, respectively, and have good thermoplastic processing properties. performance

Embodiment 8:

Take 75 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.0325mm, an average degree of polymerization of 800, and a degree of alcoholysis of 88% (mol/mol), and a number-average particle diameter of 0.0325mm, a volume crystallinity of 35%, and a weight 25 kg of poly-3-hydroxyvalerate (P-3HV) powder with an average molecular weight of 650,000 was physically mixed for the first time in a high-speed mixer at room temperature for 3 to 5 minutes; then 1 kg of water was added, Carry out the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; the mixed material is vacuum-dried at 80°C for 6 hours to remove excess water; the dried mixed material is injected into a unit with a screw aspect ratio of 20 In the screw extruder, melt and extrude at 180 ° C, adjust the screw speed to make the melting time of the mixture 6 minutes; naturally cool the extruded melt in the air, and cut into pellets with a granulator to prepare milky white, smooth surface Granular polyvinyl alcohol composite masterbatch. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 180°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 9510, 3860, and 525 Pa·s, respectively, and have good thermoplastic processing properties. performance.

Embodiment 9:

Take 90 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.01mm, an average degree of polymerization of 1000, and a degree of alcoholysis of 93.9% (mol/mol), and a number-average particle diameter of 0.01mm, a volume crystallinity of 55%, and a weight 10 kg of poly 3-hydroxyvalerate (P-3HV) powder with an average molecular weight of 370,000 was physically mixed for the first time in a high-speed mixer at room temperature for 3 to 5 minutes; then 1.5 kg of water was added, Carry out the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; the mixture is vacuum-dried at 100°C for 6 hours to remove excess water; In the screw extruder, melt and extrude at 185°C, adjust the screw speed to make the melting time of the mixture 8 minutes; naturally cool the extruded melt in the air, and cut into pellets with a granulator to prepare milky white, smooth surface Granular polyvinyl alcohol composite masterbatch. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 185°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 9850, 4260, and 580 Pa·s, respectively, and have good thermoplastic processing properties. performance.

Example 10:

Take 90 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.055mm, an average degree of polymerization of 600, and a degree of alcoholysis of 99.8% (mol/mol), and a number-average particle diameter of 0.01mm, a volume crystallinity of 30%, and a weight 10 kg of poly-3-hydroxybutyrate-4-hydroxybutyrate copolyester (P-3HB-4HB) powder with an average molecular weight of 750,000 and a molar content of 4-hydroxybutyrate (P-4HB) of 23% was processed at high speed The first physical mixing is carried out in the mixer, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; then 1.5 kg of water is added for the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; Vacuum dry at 60°C for 10 hours to remove excess moisture; inject the dried mixture into a single-screw extruder with a screw length-to-diameter ratio of 10, melt and extrude at 185°C, adjust the screw speed to make the melting time of the mixture 4 minutes; the extruded melt is naturally cooled in the air, pelletized by a granulator, and a milky white granular polyvinyl alcohol composite masterbatch with a smooth surface is prepared. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 185°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 7250, 2260, and 370 Pa·s, respectively, and have good thermoplastic processing properties. performance. Example 11:

Take 60 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.01mm, an average degree of polymerization of 800, and a degree of alcoholysis of 93.9% (mol/mol), and a number-average particle diameter of 0.055mm, a volume crystallinity of 50%, and a weight 40 kg of poly 3-hydroxybutyric acid-4-hydroxybutyric acid copolyester (P-3HB-4HB) powder with an average molecular weight of 90,000 and a molar content of 4-hydroxybutyrate (P-4HB) of 1% was processed at high speed The first physical mixing is carried out in the mixer, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; then 0.5 kg of water is added for the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; Vacuum dry at 80°C for 5 hours to remove excess moisture; inject the dried mixture into a conical twin-screw extruder with a screw aspect ratio of 20, melt and extrude at 175°C, adjust the screw speed to make the mixture The melting time is 8 minutes; the extruded melt is naturally cooled in the air, and pelletized by a granulator to prepare a milky white granular polyvinyl alcohol composite masterbatch with a smooth surface. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 175°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 7080, 2100, and 353 Pa·s, respectively, and have good thermoplastic processing properties. performance. Example 12:

Take 75 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.0325mm, an average degree of polymerization of 1000, and a degree of alcoholysis of 88% (mol/mol), and a number-average particle diameter of 0.0325mm, a volume crystallinity of 10%, and a weight 25 kg of poly-3-hydroxybutyrate-4-hydroxybutyrate copolyester (P-3HB-4HB) powder with an average molecular weight of 420,000 and a molar content of 4-hydroxybutyrate (P-4HB) of 45% was processed at high speed The first physical mixing is carried out in the mixer, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; then 1 kg of water is added for the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; Vacuum dry at 60°C for 8 hours to remove excess moisture; inject the dried mixture into a single-screw extruder with a screw aspect ratio of 30, melt and extrude at 180°C, adjust the screw speed to make the melting time of the mixture 6 minutes; the extruded melt is naturally cooled in the air, pelletized by a granulator, and a milky white granular polyvinyl alcohol composite masterbatch with a smooth surface is prepared. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 180°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 7200, 2210, and 360 Pa·s, respectively, and have good thermoplastic processing properties. performance. Example 13:

Take 75 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.01mm, an average degree of polymerization of 600, and a degree of alcoholysis of 99.8% (mol/mol), and a number-average particle diameter of 0.0325mm, a volume crystallinity of 40%, and a weight 25 kg of polyhydroxybutyrate-valeric acid copolyester (PHBV) powder with an average molecular weight of 90,000 and a molar content of 3-hydroxyvalerate (P-3HV) of 23% was physically mixed in a high-speed mixer for the first time. The mixing temperature is normal temperature, and the time is 3 to 5 minutes; then add 1 kg of water for the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; the mixture is vacuum-dried at 60°C for 8 hours to remove Excess moisture; inject the dried mixture into a conical twin-screw extruder with a screw aspect ratio of 10, melt and extrude it at 175°C, adjust the screw speed to make the melting time of the mixture 6 minutes; extrude The melt is naturally cooled in the air, pelletized by a granulator, and a milky white granular polyvinyl alcohol composite masterbatch with a smooth surface is prepared. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 175°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 7430, 2290, and 378 Pa·s, respectively, and have good thermoplastic processing properties. performance.

Example 14:

Take 90 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.0325mm, an average degree of polymerization of 800, and a degree of alcoholysis of 88% (mol/mol), and a number-average particle diameter of 0.01mm, a volume crystallinity of 15%, and a weight 10 kg of polyhydroxybutyrate-valeric acid copolyester (PHBV) powder with an average molecular weight of 420,000 and a molar content of 3-hydroxyvalerate (P-3HV) of 45% was physically mixed in a high-speed mixer for the first time, The mixing temperature is normal temperature, and the time is 3 to 5 minutes; then add 1.5 kg of water for the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; the mixture is vacuum-dried at 100°C for 6 hours to remove Excess moisture; inject the dried mixture into a single-screw extruder with a screw length-to-diameter ratio of 20, melt and extrude it at 185°C, adjust the screw speed to make the melting time of the mixture 4 minutes; extrude the melt Natural cooling in the air, granulation by a granulator, and preparation of a milky white, smooth surface granular polyvinyl alcohol composite masterbatch. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 185°C and a shear rate of 100, 1000, and 10,000 s- ¹ are 7,500, 2,320, and 390 Pa s, respectively, and have good thermoplastic processing properties. performance.

Example 15:

Take 60 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.055mm, an average degree of polymerization of 1000, and a degree of alcoholysis of 93.9% (mol/mol), and a number-average particle diameter of 0.055mm, a volume crystallinity of 65%, and a weight 40 kg of polyhydroxybutyric acid-valeric acid copolyester (PHBV) powder with an average molecular weight of 750,000 and a molar content of 3-hydroxyvalerate (P-3HV) of 1% was physically mixed in a high-speed mixer for the first time. The mixing temperature is normal temperature, and the time is 3 to 5 minutes; then add 0.5 kg of water for the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; the mixture is vacuum-dried at 80°C for 6 hours to remove Excess water; inject the dried mixture into a single-screw extruder with a screw length-to-diameter ratio of 20, melt and extrude it at 180°C, adjust the screw speed to make the melting time of the mixture 8 minutes; extrude the melt Natural cooling in the air, granulation by a granulator, and preparation of a milky white, smooth surface granular polyvinyl alcohol composite masterbatch. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 180°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 7540, 2400, and 400 Pa·s, respectively, and have good thermoplastic processing properties. performance.

Example 16:

Take 75 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.01 mm, an average degree of polymerization of 1200, and a degree of alcoholysis of 88% (mol/mol), and a number-average particle diameter of 0.055 mm, a volume crystallinity of 55%, and a weight 25 kg of poly 3-hydroxyvalerate (P-3HV) powder with an average molecular weight of 370,000 was physically mixed for the first time in a high-speed mixer, the mixing temperature was normal temperature, and the mixing time was 3 to 5 minutes; then 1 kg of water was added, Carry out the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; the mixed material is vacuum-dried at 80°C for 6 hours to remove excess water; the dried mixed material is injected into a unit with a screw aspect ratio of 30 In the screw extruder, melt and extrude at 180 ° C, adjust the screw speed to make the melting time of the mixture 6 minutes; naturally cool the extruded melt in the air, and cut into pellets with a granulator to prepare milky white, smooth surface Granular polyvinyl alcohol composite masterbatch. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 180°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 9600, 4100, and 550 Pa·s, respectively, and have good thermoplastic processing properties. performance.

Example 17:

Take 51 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.1mm, an average degree of polymerization of 1800, and a degree of alcoholysis of 93.9% (mol/mol), and a number-average particle diameter of 0.1mm, a volume crystallinity of 70%, and a weight 49 kg of poly-4-hydroxybutyrate (P-4HB) powder with an average molecular weight of 650,000 was physically mixed for the first time in a high-speed mixer at room temperature for 3 to 5 minutes; then 0.5 kg of water was added, Carry out the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; the mixed material is vacuum-dried at 100°C for 6 hours to remove excess water; the dried mixed material is injected into a unit with a screw aspect ratio of 10 In the screw extruder, melt and extrude at 185°C, adjust the screw speed to make the melting time of the mixture 4 minutes; cool the extruded melt naturally in the air, and cut into pellets with a granulator to prepare milky white and smooth surface Granular polyvinyl alcohol composite masterbatch. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 185°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 8850, 2920, and 448 Pa·s, respectively, and have good thermoplastic processing properties. performance.

Example 18:

Take 99 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.055mm, an average degree of polymerization of 600, and a degree of alcoholysis of 99.8% (mol/mol), and a number-average particle diameter of 0.01mm, a volume crystallinity of 65%, and a weight 1 kg of polyhydroxybutyric acid-valeric acid copolyester (PHBV) powder with an average molecular weight of 90,000 and a molar content of 3-hydroxyvalerate (P-3HV) of 1% was physically mixed in a high-speed mixer for the first time, The mixing temperature is normal temperature, and the time is 3 to 5 minutes; then add 1.5 kg of water for the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; the mixture is vacuum-dried at 60°C for 10 hours to remove Excess moisture; inject the dried mixture into a twin-screw extruder with a screw aspect ratio of 20, melt and extrude it at 175°C, adjust the screw speed to make the melting time of the mixture 8 minutes; extrude the melt Natural cooling in the air, granulation by a granulator, and preparation of a milky white, smooth surface granular polyvinyl alcohol composite masterbatch. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 175°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 10030, 3110, and 452 Pa·s, respectively, and have good thermoplastic processing properties. performance.

Example 19:

Take 60 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.055mm, an average degree of polymerization of 1000, and a degree of alcoholysis of 88% (mol/mol), and a number-average particle diameter of 0.1mm, a volume crystallinity of 55%, and a weight 40 kg of poly-3-hydroxyvalerate (P-3HV) powder with an average molecular weight of 370,000 was physically mixed for the first time in a high-speed mixer at room temperature for 3 to 5 minutes; then 0.5 kg of water was added, Carry out the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; the mixed material is vacuum-dried at 80°C for 6 hours to remove excess water; the dried mixed material is injected into a unit with a screw aspect ratio of 30 In the screw extruder, melt and extrude at 175°C, adjust the screw speed so that the melting time of the mixture is 4 minutes; naturally cool the extruded melt in the air, and cut into pellets with a granulator to prepare milky white, smooth surface Granular polyvinyl alcohol composite masterbatch. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 175°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 8600, 2730, and 425 Pa·s, respectively, and have good thermoplastic processing properties. performance.

Example 20:

Take 90 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.0325mm, an average degree of polymerization of 800, and a degree of alcoholysis of 88% (mol/mol), and a number-average particle diameter of 0.1mm, a volume crystallinity of 40%, and a weight 10 kg of polyhydroxybutyrate-valeric acid copolyester (PHBV) powder with an average molecular weight of 500,000 and a molar content of 3-hydroxyvalerate (P-3HV) of 45% was physically mixed in a high-speed mixer for the first time. The mixing temperature is normal temperature, and the time is 3 to 5 minutes; then add 1.5 kg of water for the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; the mixture is vacuum-dried at 100°C for 6 hours to remove Excess moisture; inject the dried mixture into a single-screw extruder with a screw length-to-diameter ratio of 20, melt and extrude it at 185°C, adjust the screw speed to make the melting time of the mixture 4 minutes; extrude the melt Natural cooling in the air, granulation by a granulator, and preparation of a milky white, smooth surface granular polyvinyl alcohol composite masterbatch. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 185°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 9,000, 3,020, and 460 Pa·s, respectively, and have good thermoplastic processing properties. performance.

Example 21:

Take 75 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.0325mm, an average degree of polymerization of 1000, and a degree of alcoholysis of 88% (mol/mol), and a number-average particle diameter of 0.1mm, a volume crystallinity of 10%, and a weight 25 kg of poly-3-hydroxybutyrate-4-hydroxybutyrate copolyester (P-3HB-4HB) powder with an average molecular weight of 420,000 and a molar content of 4-hydroxybutyrate (P-4HB) of 45% was processed at high speed The first physical mixing is carried out in the mixer, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; then 1 kg of water is added for the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; Vacuum dry at 60°C for 8 hours to remove excess moisture; inject the dried mixture into a single-screw extruder with a screw aspect ratio of 30, melt and extrude at 180°C, adjust the screw speed to make the melting time of the mixture 6 minutes; the extruded melt is naturally cooled in the air, pelletized by a granulator, and a milky white granular polyvinyl alcohol composite masterbatch with a smooth surface is prepared. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 180°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 6750, 1900, and 310 Pa·s, respectively, and have good thermoplastic processing properties. performance.

Example 22:

Take 60 kg of polyvinyl alcohol powder with a number-average particle diameter of 0.01mm, an average degree of polymerization of 800, and a degree of alcoholysis of 99.8% (mol/mol), and a number-average particle diameter of 0.1mm, a volume crystallinity of 50%, and a weight 40 kg of poly-3-hydroxybutyrate (P-3HB) powder with an average molecular weight of 90,000 was physically mixed for the first time in a high-speed mixer at room temperature for 3 to 5 minutes; then 1.5 kg of water was added, Carry out the second physical mixing, the mixing temperature is normal temperature, and the time is 3 to 5 minutes; the mixture is vacuum-dried at 100°C for 6 hours to remove excess water; the dried mixture is injected into a cone with a screw length-to-diameter ratio of 10 In a twin-screw extruder, melt and extrude at 185°C, adjust the screw speed so that the melting time of the mixture is 8 minutes; the extruded melt is naturally cooled in the air, and pelletized by a granulator to prepare milky white, Granular polyvinyl alcohol compound masterbatch with smooth surface. Measured by a capillary rheometer, the apparent shear viscosities of the masterbatch at a temperature of 185°C and a shear rate of 100, 1000, and 10,000 s ^-1 are 9200, 3360, and 475 Pa·s, respectively, and have good thermoplastic processing properties. performance.

The above embodiments do not limit the present invention, and the present invention is not limited to the above embodiments, as long as the requirements of the present invention are met, they all belong to the protection scope of the present invention.

Claims (5)

1. A composite masterbatch of polyvinyl alcohol, which is a blend, is characterized in that the blend comprises polyvinyl alcohol, polyhydroxyalkanoate; wherein the weight content of polyvinyl alcohol is 51～99%, polyhydroxyalkanoate The weight content of the ester is 1-49%, and the apparent shear viscosity of the polyvinyl alcohol composite masterbatch is lower than 20000Pa·s under the conditions of 175-185°C and 100s ^-1 shear rate; The average degree of polymerization of polyvinyl alcohol is 600-1800, and the degree of alcoholysis is 88%-99.8%, the unit is mol/mol; Polyhydroxyalkanoate has the following general chemical structure formula: In the general formula, R1 is H, m1 is ₂ , x is any natural number from 200 to 20000, and when y is 0, polyhydroxyalkanoate is poly4-hydroxybutyrate, and its number average particle diameter is 0.01 to 0.1mm , the volume crystallinity is 30-70%, and the weight-average molecular weight is 9-650,000; In the general formula, R ₁ is ethyl C ₂ H ₅ , m1 is 1, x is any natural number from 200 to 20000, and when y is 0, the polyhydroxyalkanoate is poly-3-hydroxyvalerate, and its number-average particle diameter 0.01-0.1mm, the volume crystallinity is 15-55%, and the weight-average molecular weight is 9-650,000; In the general formula, when R ₁ is methyl CH ₃ , R ₂ is H, m1 is 1, m2 is 2, x and y are any natural numbers from 200 to 20000, polyhydroxyalkanoate is poly 3-hydroxybutyric acid- 4-Hydroxybutyric acid copolyester has a number-average particle diameter of 0.01-0.1mm, a volume crystallinity of 10-50%, and a weight-average molecular weight of 90,000-750,000. The molar content of 4-hydroxybutyrate is 1～45﹪; In the general formula, when R ₁ is methyl CH ₃ , R ₂ is ethyl C ₂ H ₅ , m1 and m2 are both 1, and x and y are any natural numbers ranging from 200 to 20000, polyhydroxyalkanoate is polyhydroxybutyrate Acid-valeric acid copolyester, the number-average particle diameter is 0.01-0.1 mm, the volume crystallinity is 15-65%, the weight-average molecular weight is 9-750,000, and the molar content of 3-hydroxyvaleric acid ester is 1 ~45% 2. A kind of polyvinyl alcohol composite masterbatch as claimed in claim 1, it is characterized in that in the polyvinyl alcohol composite masterbatch, the weight content of polyvinyl alcohol is 60～90%, and the weight content of polyhydroxyalkanoate is 10% ~40%, the apparent shear viscosity of polyvinyl alcohol composite masterbatch is lower than 10000Pa·s under the conditions of 175~185℃ and 100s ^-1 shear rate; The average degree of polymerization of polyvinyl alcohol is 600-1000, and the degree of alcoholysis is 88%-99.8%, the unit is mol/mol. 3. prepare the method for a kind of polyvinyl alcohol composite masterbatch as claimed in claim 1, it is characterized in that the method comprises the following steps: Step (1). The polyvinyl alcohol powder and the polyhydroxyalkanoate powder are physically mixed for the first time, and then deionized water is added for the second physical mixing, and the mixture is obtained after mixing; wherein the polyvinyl alcohol and the polyhydroxyalkanoate The weight ratio of hydroxy fatty acid ester is 51:49～99:1, and the weight of deionized water is 0.5～1.5% of the total weight of polyvinyl alcohol and polyhydroxy fatty acid ester; The polyvinyl alcohol has a number-average particle diameter of 0.01-0.1mm, an average degree of polymerization of 600-1800, and a degree of alcoholysis of 88%-99.8%, the unit being mol/mol; Described polyhydroxyalkanoate has following general chemical structure formula: In the general formula, R1 is H, m1 is ₂ , x is any natural number from 200 to 20000, and when y is 0, polyhydroxyalkanoate is poly4-hydroxybutyrate, and its number average particle diameter is 0.01 to 0.1mm , the volume crystallinity is 30-70%, and the weight-average molecular weight is 9-650,000; In the general formula, R ₁ is ethyl C ₂ H ₅ , m1 is 1, x is any natural number from 200 to 20000, and when y is 0, the polyhydroxyalkanoate is poly-3-hydroxyvalerate, and its number-average particle diameter 0.01-0.1mm, the volume crystallinity is 15-55%, and the weight-average molecular weight is 9-650,000; In the general formula, when R ₁ is methyl CH ₃ , R ₂ is H, m1 is 1, m2 is 2, x and y are any natural numbers from 200 to 20000, polyhydroxyalkanoate is poly 3-hydroxybutyric acid- 4-Hydroxybutyric acid copolyester has a number-average particle diameter of 0.01-0.1mm, a volume crystallinity of 10-50%, and a weight-average molecular weight of 90,000-750,000. The molar content of 4-hydroxybutyrate is 1～45﹪; In the general formula, when R ₁ is methyl CH ₃ , R ₂ is ethyl C ₂ H ₅ , m1 and m2 are both 1, and x and y are any natural numbers ranging from 200 to 20000, polyhydroxyalkanoate is polyhydroxybutyrate Acid-valeric acid copolyester, the number-average particle diameter is 0.01-0.1 mm, the volume crystallinity is 15-65%, the weight-average molecular weight is 9-750,000, and the molar content of 3-hydroxyvaleric acid ester is 1 ~45%; Step (2). Vacuum-dry the mixture obtained in step (1) at 60-100° C. until the constant weight remains unchanged, and remove excess water; Step (3). Inject the dried mixture of step (2) into a screw extruder with a heating device. The length-to-diameter ratio of the screw is 10-30, melted at 175-185°C for 4-8 minutes, and melt-extruded Get extruded melt; Step (4). The extruded melt in step (3) is naturally cooled to normal temperature in the air, and pelletized by a granulator to prepare a granular polyvinyl alcohol composite masterbatch that can be used for thermoplastic processing. 4. The preparation method of a polyvinyl alcohol composite masterbatch as claimed in claim 3, characterized in that the weight ratio of polyvinyl alcohol to polyhydroxyalkanoate is 6:4-9:1. 5. the preparation method of a kind of polyvinyl alcohol composite masterbatch as claimed in claim 3 is characterized in that the number-average particle diameter of polyvinyl alcohol is 0.01～0.055mm, and average polymerization degree is 600～1000, and alcoholysis degree is 88﹪～99.8﹪, the unit is mol/mol.