Polyvinyl alcohol composition, polyvinyl alcohol resin and preparation method and application thereof

Abstract

The invention relates to the field of polyvinyl alcohol, and discloses a polyvinyl alcohol composition, polyvinyl alcohol resin and a preparation method and application thereof. The polyvinyl alcohol composition is prepared from 50 to 90 weight percent of polyvinyl alcohol, 5 to 15 weight percent of plasticizer, 0.001 to 10 weight percent of antioxidant, 1 to 10 weight percent of inorganic filler and 0.01 to 5 weight percent of decomposition-resistant agent; the decomposition-resistant agent contains a component A and a component B; the component A is selected from at least one of boric acid, zinc sulfate, titanium dioxide, tartaric acid and maleic acid; the component B is selected from at least two of magnesium hydroxide, calcium stearate and monopotassium phosphate. The composition contains a specific content of the plasticizer and the decomposition-resistant agent, the component A and the component B in the decomposition-resistant agent can cooperate with other components to jointly play a role, the thermal decomposition temperature of the polyvinyl alcohol resin prepared from the composition is increased, and the composition has good fluidity and meets the use requirements in a high-temperature environment.

Description

Technical Field

[0001] The invention relates to the field of polyvinyl alcohol, and in particular to a polyvinyl alcohol composition, a polyvinyl alcohol resin, and a preparation method and application thereof. Background Art

[0002] Polyvinyl alcohol is a general-purpose and functional polymer material with excellent performance and wide application. It has strong adhesion, smoothness, film flexibility, oil resistance, protective colloid, solvent resistance, gas barrier, wear resistance, and water resistance after special treatment. Polyvinyl alcohol is non-toxic, odorless, and harmless to the human body. It has good affinity with the natural environment, does not accumulate, and does not pollute. Therefore, it is widely used in fiber materials, coatings, emulsifiers, adhesives, films, paper processing agents and dispersants.

[0003] However, polyvinyl alcohol is a crystalline polymer with a large number of hydroxyl groups in its molecules, which can form a large number of intramolecular and intermolecular hydrogen bonds, making its melting point as high as 200-240°C. However, in the air, polyvinyl alcohol will slowly change color and become brittle when heated to above 100°C; it will fully soften and melt above 150°C; when heated to above 160°C, the color will become very dark; above 170°C, the color is darker; when heated to above 220°C, polyvinyl alcohol will rapidly decompose to produce acetic acid, acetaldehyde, butenol and water; polyvinyl alcohol that does not have time to decompose at above 250°C will become a polymer containing conjugated double bonds. Therefore, the melting point of PVA is close to the decomposition temperature, making it difficult to directly thermoplasticize and mold.

[0004] At present, thermoplastic polyvinyl alcohol resins are increasingly used in the field of injection molding, mainly for complex electronic product models, protective shells, etc. It utilizes the good water-soluble properties of polyvinyl alcohol, so that complex electronic product models or other products can be quickly demolded in water. However, its process requires that injection-grade polyvinyl alcohol resins need to withstand 260-330°C, which is a huge challenge for thermoplastic polyvinyl alcohol resins. However, the thermoplastic polyvinyl alcohol injection molding materials currently on the market will lose their physical properties at high temperatures, resulting in product failure. Most of the domestic and foreign technologies are to weaken the hydrogen bonding forces within and between polyvinyl alcohol molecules by copolymerization or adding plasticizers to blend, lower its melting point, and make it thermoplastic processable, thereby obtaining a melt-processable modified polyvinyl alcohol resin or a polyvinyl alcohol blended modified resin, but the improvement effect is not obvious. Therefore, there is a need for a thermoplastic polyvinyl alcohol resin that can maintain its performance at high temperatures. Summary of the invention

[0005] The object of the present invention is to overcome the problem in the prior art that polyvinyl alcohol and polyvinyl alcohol products have a low processing temperature and cannot be well applied to scenarios of 250 °C and above, thereby restricting their applications. Provided are a polyvinyl alcohol composition, a polyvinyl alcohol resin, a preparation method thereof and an application. In this polyvinyl alcohol composition, a plasticizer and a decomposition-resistant agent with specific contents are contained. Component A and component B in the decomposition-resistant agent can cooperate with other components in the composition to jointly play a role, thereby increasing the thermal decomposition temperature of the polyvinyl alcohol resin prepared from this composition. At the same time, it has good fluidity and molding properties, meeting the usage requirements in high-temperature environments.

[0006] To achieve the above object, in the first aspect of the present invention, a polyvinyl alcohol composition is provided. The polyvinyl alcohol composition comprises: 50 - 90 wt% of polyvinyl alcohol, 5 - 15 wt% of a plasticizer, 0.001 - 10 wt% of an antioxidant, 1 - 10 wt% of an inorganic filler, and 0.001 - 5 wt% of a decomposition-resistant agent;

[0007] Wherein, the decomposition-resistant agent contains component A and component B;

[0008] Component A is selected from at least one of boric acid, zinc sulfate, titanium dioxide, tartaric acid, and maleic acid;

[0009] Component B is selected from at least two of magnesium hydroxide, calcium stearate, and potassium dihydrogen phosphate.

[0010] In the second aspect of the present invention, a method for preparing a polyvinyl alcohol resin is provided. The method comprises:

[0011] S1. Mix the polyvinyl alcohol composition described in the first aspect of the present invention and optionally keep it warm;

[0012] S2. Melt-extrude and cool the material in step S1 to obtain a polyvinyl alcohol resin.

[0013] In the third aspect of the present invention, a polyvinyl alcohol resin prepared by the method described in the second aspect of the present invention is provided.

[0014] In the fourth aspect of the present invention, an application of the polyvinyl alcohol resin described in the third aspect of the present invention in at least one field of flexible packaging, toys, vehicle parts, and electrical accessories is provided.

[0015] Through the above technical solutions, the polyvinyl alcohol composition, polyvinyl alcohol resin, and their preparation methods and applications provided by the present invention achieve the following beneficial effects: In the polyvinyl alcohol composition, a specific content of a plasticizer and a decomposition-resistant agent are contained. Component A and Component B in the decomposition-resistant agent can cooperate with the antioxidant in the composition to play a role together. Component B can capture the acidic substances generated at the initial stage of thermal decomposition, inhibit the sour taste of the resin, and the antioxidant captures free radicals in the stage of thermal-oxidative decomposition, alleviating the rapid decomposition of molecular chain segments. From the initial stage of thermal decomposition to the stage of thermal-oxidative decomposition, the purpose of making polyvinyl alcohol not easily thermally decomposed is achieved together. The thermal decomposition temperature of the polyvinyl alcohol resin prepared from this composition is increased, and at the same time, it has good fluidity and mechanical properties, meeting the usage requirements in high-temperature environments. Description of the Drawings

[0016] Figure 1 It is the thermogravimetric analysis test results of the examples and Comparative Example 1 of the present invention.

[0017] Description of the Reference Numerals

[0018] 1. Example 1; 2. Example 2; 3. Example 3; 4. Example 5; 5. Example 6; 6. Comparative Example 1. Detailed Embodiments

[0019] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0020] The first aspect of the present invention provides a polyvinyl alcohol composition, which comprises: 50 - 90 wt% of polyvinyl alcohol, 5 - 15 wt% of a plasticizer, 0.001 - 10 wt% of an antioxidant, 1 - 10 wt% of an inorganic filler, and 0.001 - 5 wt% of a decomposition-resistant agent;

[0021] Wherein, the decomposition-resistant agent contains Component A and Component B;

[0022] Component A is selected from at least one of boric acid, zinc sulfate, titanium dioxide, tartaric acid, and maleic acid;

[0023] Component B is selected from at least two of magnesium hydroxide, calcium stearate, and potassium dihydrogen phosphate.

[0024] In the present invention, the inventors found that in the prior art, relying solely on adding plasticizers would reduce the strength and soften the prepared polyvinyl alcohol resin, thereby reducing the usability of the material. Each component of the composition provided by the present invention cooperates synergistically, and can jointly improve the strength and decomposition resistance temperature of the prepared polyvinyl alcohol resin. Further, the composition contains a specific combination of decomposition-resistant agents. Under the action of component A, the prepared resin has a certain degree of crosslinking. At the same time, component A and component B in the decomposition-resistant agent can cooperate with the antioxidant in the composition to play a joint role, which can not only increase the thermal decomposition temperature of the polyvinyl alcohol resin prepared from the composition at high temperatures, but also promote the integrity of the crystallization of polyvinyl alcohol, so that the polyvinyl alcohol resin prepared from the composition has good mechanical properties.

[0025] In the present invention, in the polyvinyl alcohol composition, the content of polyvinyl alcohol can be 50wt%, 51wt%, 52wt%, 55wt%, 56wt%, 58wt%, 60wt%, 61wt%, 62wt%, 65wt%, 66wt%, 68wt%, 70wt%, 71wt%, 72wt%, 75wt%, 76wt%, 78wt%, 80wt%, 81wt%, 82wt%, 85wt%, 86wt%, 88wt%, 90wt% and any value between any two values.

[0026] In the present invention, in the polyvinyl alcohol composition, the content of the plasticizer can be 5wt%, 5.5wt%, 6wt%, 7wt%, 8wt%, 8.5wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt% and any value between any two values.

[0027] In the present invention, in the polyvinyl alcohol composition, the content of the antioxidant can be 0.001wt%, 0.002wt%, 0.005wt%, 0.008wt%, 0.01wt%, 0.02wt%, 0.05wt%, 0.08wt%, 0.1wt%, 0.3wt%, 0.5wt%, 0.8wt%, 1wt%, 2wt%, 3wt%, 5wt%, 5.5wt%, 7wt%, 8.5wt%, 9wt%, 10wt% and any value between any two values.

[0028] In the present invention, in the polyvinyl alcohol composition, the content of the inorganic filler can be 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 5wt%, 5.5wt%, 7wt%, 9wt%, 10wt% and any value between any two values.

[0029] In the present invention, in the polyvinyl alcohol composition, the content of the decomposition-resistant agent is 0.001-5 wt%, and can be 0.001 wt%, 0.002 wt%, 0.005 wt%, 0.008 wt%, 0.01 wt%, 0.02 wt%, 0.05 wt%, 0.08 wt%, 0.1 wt%, 0.3 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 2 wt%, 3 wt%, 5 wt%, and any value between any two of these values.

[0030] According to the present invention, the polyvinyl alcohol composition comprises: 80-90 wt% of polyvinyl alcohol, 6.5-12 wt% of a plasticizer, 0.6-0.8 wt% of an antioxidant, 5-6 wt% of an inorganic filler, and 0.2-0.35 wt% of a decomposition-resistant agent.

[0031] According to the present invention, the mass ratio of component A to component B is 1:10-50.

[0032] Through further research by the inventors of the present invention, it has been found that when the mass ratio of component A to component B satisfies the above range, the decomposition temperature of polyvinyl alcohol can be further increased. At the same time, adding the above content of inorganic filler can further reduce the production cost on the premise of not affecting its thermal decomposition performance.

[0033] In the present invention, the mass ratio of component A to component B can be 1:10, 1:11, 1:12, 1:13, 1:15, 1:18, 1:20, 1:21, 1:23, 1:25, 1:30, 1:33, 1:35, 1:39, 1:40, 1:42, 1:46, 1:48, 1:50, and any ratio between any two of the above ratios.

[0034] Furthermore, the mass ratio of component A to component B is 1:15-42.

[0035] According to the present invention, the degree of polymerization of the polyvinyl alcohol is 300-2400.

[0036] In the present invention, the degree of polymerization of the polyvinyl alcohol can be 300, 400, 500, 600, 700, 800, 900, 1000, 1300, 1700, 1800, 2000, 2200, 2300, 2400, and any value between any two of these values.

[0037] Furthermore, the degree of polymerization of the polyvinyl alcohol is 400-2000, more preferably 500-1700.

[0038] According to the present invention, the degree of alcoholysis of the polyvinyl alcohol is DA, where 72 mol% ≤ DA ≤ 99 mol%.

[0039] In the present invention, the degree of alcoholysis of the polyvinyl alcohol satisfies the above range, which can ensure that the polyvinyl alcohol used is a non-fully alcoholized polyvinyl alcohol with good water solubility, and can make the prepared polyvinyl alcohol resin have good water solubility.

[0040] In the present invention, the degree of alcoholysis of the polyvinyl alcohol can be any value between 72 mol%, 80 mol%, 82 mol%, 86 mol%, 88 mol%, 90 mol%, 92 mol%, 94 mol%, 96 mol%, 98 mol%, 99 mol% and any range composed of any two values.

[0041] Further, the degree of alcoholysis of the polyvinyl alcohol is DA, and 86 mol% ≤ DA ≤ 94 mol%.

[0042] According to the present invention, the plasticizer is selected from at least one of pentaerythritol, trimethylolpropane (TMP), alkyl polyglycoside (APG0810), and nonylphenol polyoxyethylene ether (NP-10).

[0043] In the present invention, the decomposition-resistant agent and the plasticizer in the composition cooperate with each other to improve the maximum decomposition-resistant temperature of the resin.

[0044] According to the present invention, the antioxidant is selected from at least one of phosphite antioxidants, hindered phenol antioxidants, and aromatic amine antioxidants.

[0045] In the present invention, component A and component B in the decomposition-resistant agent can cooperate with the above antioxidant to play a role together, and jointly improve the thermal stability of polyvinyl alcohol.

[0046] According to a preferred embodiment of the present invention, the antioxidant is selected from at least two of antioxidant 686, antioxidant 1010, antioxidant 697, antioxidant 1098, and antioxidant B215.

[0047] According to the present invention, the inorganic filler is selected from at least one of talcum powder, kaolin, and nano calcium carbonate.

[0048] The second aspect of the present invention provides a method for preparing a polyvinyl alcohol resin, and the method includes:

[0049] S1. Mix the polyvinyl alcohol composition described in the first aspect of the present invention and optionally keep it warm;

[0050] S2. Melt-extrude and cool the material in step S1 to obtain a polyvinyl alcohol resin.

[0051] According to the present invention, the conditions for mixing include: the rotation speed is 300 - 600 r / min, and the temperature is 70 - 75 °C.

[0052] According to the present invention, the conditions for heat preservation include: the temperature is 25 - 90°C, and the time is 0 - 10 h.

[0053] In the present invention, the temperature for heat preservation can be 25°C, 26°C, 28°C, 30°C, 32°C, 36°C, 40°C, 42°C, 46°C, 50°C, 52°C, 56°C, 58°C, 60°C, 62°C, 66°C, 68°C, 70°C, 72°C, 76°C, 78°C, 80°C, 85°C, 88°C, 90°C, and any value between any two numerical values.

[0054] In the present invention, the time for heat preservation can be 0 h, 1 h, 1.5 h, 3 h, 4.5 h, 5 h, 5.5 h, 6 h, 6.5 h, 7 h, 7.5 h, 8 h, 9 h, 10 h, and any value between any two numerical values.

[0055] Further, the conditions for heat preservation include: the temperature is 70 - 75°C, and the time is 0.5 - 1 h.

[0056] In the present invention, the conditions for heat preservation further satisfy that the temperature is 70 - 75°C and the time is 0.5 - 1 h, which can ensure that all materials are evenly mixed and fully play their roles.

[0057] According to the present invention, in step S2, the temperature for melt extrusion is 120 - 220°C.

[0058] In the present invention, when the temperature for melt extrusion satisfies the above range, granulation can be smoothly carried out, and further, the composition has good fluidity.

[0059] Further, in step S2, the temperature for melt extrusion is 190 - 200°C.

[0060] According to the present invention, the temperature for cooling is 15 - 40°C, preferably 20 - 30°C.

[0061] The third aspect of the present invention provides a polyvinyl alcohol resin prepared by the method described in the second aspect of the present invention.

[0062] In the present invention, the polyvinyl alcohol resin has good fluidity and moldability. Among them, the melt index of the polyvinyl alcohol is 10 - 20 g / 10 min (2.16 kg, 230°C), preferably 15 - 20 g / 10 min (2.16 kg, 230°C).

[0063] According to the present invention, the maximum decomposition temperature of the polyvinyl alcohol resin ≥ 260°C, preferably ≥ 290°C, more preferably ≥ 310°C

[0064] In the present invention, the maximum decomposition temperature refers to the temperature corresponding to the point where the weight loss curve of the polyvinyl alcohol resin shows the fastest decline (i.e., the maximum slope) during thermogravimetric testing in a nitrogen atmosphere.

[0065] In the present invention, the inventors have found that the polyvinyl alcohol resin not only meets the thermal stability requirements of the process, but also has good water solubility for the injection-molding and water-soluble demolding process requirements, and can be completely dissolved within a specified time. The polyvinyl alcohol resin prepared by the present invention can be completely dissolved within 10 - 120 min under normal temperature conditions with stirring set at 100 - 120 revolutions per minute, fully meeting the requirement of the dissolution residue content of 1 - 20 wt% required by the process.

[0066] The fourth aspect of the present invention provides an application of the polyvinyl alcohol resin described in the third aspect of the present invention in at least one field of flexible packaging, toys, vehicle parts, and electrical accessories.

[0067] According to a particularly preferred embodiment of the present invention, the polyvinyl alcohol composition comprises: 80 - 90 wt% of polyvinyl alcohol, 6.5 - 10 wt% of a plasticizer, 0.6 - 0.8 wt% of an antioxidant, 5 - 6 wt% of an inorganic filler, and 0.2 - 0.35 wt% of a decomposition-resistant agent;

[0068] Among them, the component A is selected from at least one of boric acid, titanium dioxide, or tartaric acid;

[0069] The component B is selected from magnesium hydroxide and calcium stearate, and the mass ratio of magnesium hydroxide to calcium stearate is 1:150 - 200;

[0070] The mass ratio of component A to component B is 1:15.1 - 40.2.

[0071] When the above ranges are met, the prepared polyethylene resin has significantly better properties, among which the melt index is not less than 18.1 g / 10 min -1 and at the same time, the maximum decomposition temperature is not less than 312 °C, the tensile strength is not less than 85 MPa, and the impact strength is not less than 2.4 kJ / m 2 .

[0072] The present invention will be described in detail below through examples.

[0073] In the following examples, the melt index was measured by the melt index instrument method, and the test method was in accordance with the ASTM D 1238 and GB / T3682 standards;

[0074] Thermogravimetric analysis was measured by a thermogravimetric analyzer, and the test method was carried out under a nitrogen atmosphere in accordance with the GBT27761-2011 standard. Tensile strength was measured using a universal mechanical testing machine, and the test method was in accordance with the ASTM D638, ISO527, and GB / T1040 standards.

[0075] The raw material is the commercially available Chuanwei brand polyvinyl alcohol from Sinopec Chongqing Chuanwei Chemical Industry.

[0076] In the following examples, unless otherwise specified, the inorganic filler is talc powder, and the dosage is in g.

[0077] Example 1

[0078] Mix, keep warm, melt-extrude and cool it according to the following formula of the polyvinyl alcohol composition to obtain a polyethylene resin. Among them, the mixing is carried out at 400 r / min and 70 °C for physical mixing for 0.5 h, and kept warm at 70 °C for 0.5 h; then the material enters a twin-screw extruder for melt-extrusion granulation, the melt-extrusion temperature is 200 °C, the extruded spline is cooled at about 20 °C and then enters a pelletizer for pelletizing, and the particles are packed and packaged, which is the required polyethylene resin product;

[0079] Among them, the formula is as follows: the degree of polymerization of PVA is 1700, the degree of alcoholysis is 88 mol%, and the dosage of PVA is 500 g; the plasticizer is: 40 g of pentaerythritol and 10 g of NP-10; the antioxidant is: 1.5 g of antioxidant 686 and 2.5 g of antioxidant 1010; the dosage of the inorganic filler talc powder is 30 g; the component A in the decomposition-resistant agent is 0.05 g of boric acid; the component B in the decomposition-resistant agent is 0.01 g of magnesium hydroxide and 2 g of calcium stearate.

[0080] Example 2

[0081] Mix, keep warm, melt-extrude and cool it according to the following formula of the polyvinyl alcohol composition to obtain a polyethylene resin. Among them, the mixing is carried out at 400 r / min and 70 °C for physical mixing for 0.5 h, and kept warm at 70 °C for 0.5 h; then the material enters a twin-screw extruder for melt-extrusion granulation, the melt-extrusion temperature is 200 °C, the extruded spline is cooled at about 20 °C and then enters a pelletizer for pelletizing, and the particles are packed and packaged, which is the required polyethylene resin product;

[0082] Among them, the formula is as follows: the degree of polymerization of PVA is 800, the degree of alcoholysis is 88 mol%, and the amount of PVA used is 500 g; the plasticizer is: 40 g of APG0810 and 10 g of NP-10; the antioxidant is: 1.5 g of antioxidant 686 and 2.5 g of antioxidant 1010; the amount of inorganic filler used is 30 g; component A of the decomposition-resistant agent is 0.1 g of titanium dioxide; component B of the decomposition-resistant agent is 0.01 g of magnesium hydroxide and 1.5 g of calcium stearate.

[0083] Example 3

[0084] Mix, keep warm, melt-extrude and cool it according to the following formula of the polyvinyl alcohol composition to obtain a polyethylene resin. Among them, the mixing is carried out by physical mixing at 400 r / min and 70 °C for 0.5 h, and kept warm at 70 °C for 0.5 h; then the material enters a twin-screw extruder for melt-extrusion granulation, the melt-extrusion temperature is 200 °C, the extruded spline is cooled at about 20 °C and then enters a pelletizer for pelletizing, and the pellets are packaged for packaging, which is the required polyethylene resin product;

[0085] Among them, the formula is as follows: the degree of polymerization of PVA is 1000, the degree of alcoholysis is 88 mol%, and the amount of PVA used is 500 g; the plasticizer is: 40 g of APG0810 and 10 g of NP-10; the antioxidant is: 1.5 g of antioxidant 697 and 2.5 g of antioxidant 1098; the amount of inorganic filler used is 30 g; component A of the decomposition-resistant agent is 0.05 g of boric acid; component B of the decomposition-resistant agent is 0.01 g of magnesium hydroxide and 1.5 g of calcium stearate.

[0086] Example 4

[0087] Mix, keep warm, melt-extrude and cool it according to the following formula of the polyvinyl alcohol composition to obtain a polyethylene resin. Among them, the mixing is carried out by physical mixing at 400 r / min and 70 °C for 0.5 h, and kept warm at 70 °C for 0.5 h; then the material enters a twin-screw extruder for melt-extrusion granulation, the melt-extrusion temperature is 200 °C, the extruded spline is cooled at about 20 °C and then enters a pelletizer for pelletizing, and the pellets are packaged for packaging, which is the required polyethylene resin product;

[0088] Among them, the formula is as follows: the degree of polymerization of PVA is 1300, the degree of alcoholysis is 88 mol%, and the amount of PVA used is 500 g; the plasticizer is: 40 g of pentaerythritol; the antioxidant is: 1.5 g of antioxidant 686 and 2.5 g of antioxidant 1010; the amount of inorganic filler used is 30 g; component A of the decomposition-resistant agent is 0.1 g of tartaric acid; component B of the decomposition-resistant agent is 0.01 g of magnesium hydroxide and 2 g of calcium stearate.

[0089] Example 5

[0090] Mix, heat-insulate, melt-extrude and cool the following polyvinyl alcohol composition to obtain a polyethylene resin. Among them, the mixing is carried out at 400 r / min and 70 °C for physical mixing for 0.5 h, and heat-insulated at 70 °C for 0.5 h; then the material enters a twin-screw extruder for melt-extrusion granulation. The melt-extrusion temperature is 200 °C. The extruded spline is cooled at about 20 °C and then enters a pelletizer for pelletizing. The pellets are packed for packaging, which is the required polyethylene resin product;

[0091] Among them, the formula is as follows: the degree of polymerization of PVA is 500, the degree of alcoholysis is 92 mol%, and the dosage of PVA is 500 g; the plasticizer is: 40 g of APG0810 and 10 g of NP-10; the antioxidant is: 1.5 g of antioxidant 1010 and 2.5 g of antioxidant B215; the dosage of inorganic filler is 30 g; the component A in the decomposition-resistant agent is 0.05 g of boric acid and 0.1 g of zinc sulfate; the component B in the decomposition-resistant agent is 0.01 g of magnesium hydroxide, 2 g of calcium stearate and 0.25 g of potassium dihydrogen phosphate.

[0092] Example 6

[0093] Mix, heat-insulate, melt-extrude and cool the following polyvinyl alcohol composition to obtain a polyethylene resin. Among them, the mixing is carried out at 400 r / min and 70 °C for physical mixing for 0.5 h, and heat-insulated at 70 °C for 0.5 h; then the material enters a twin-screw extruder for melt-extrusion granulation. The melt-extrusion temperature is 200 °C. The extruded spline is cooled at about 20 °C and then enters a pelletizer for pelletizing. The pellets are packed for packaging, which is the required polyethylene resin product;

[0094] Among them, the formula is as follows: the degree of polymerization of PVA is 800, the degree of alcoholysis is 88 mol%, and the dosage of PVA is 500 g; the plasticizer is: 40 g of TMP and 10 g of NP-10; the antioxidant is: 1.5 g of antioxidant 686 and 2.5 g of antioxidant 1010; the dosage of inorganic filler is 30 g; the component A in the decomposition-resistant agent is 0.1 g of maleic acid; the component B in the decomposition-resistant agent is 0.01 g of magnesium hydroxide and 1.5 g of calcium stearate.

[0095] Example 7

[0096] Mix, heat-insulate, melt-extrude, and cool the polyvinyl alcohol composition according to the following formula to obtain a polyethylene resin. Among them, the mixing is carried out by physical mixing at 400 r / min and 70 °C for 0.5 h, and heat-insulated at 70 °C for 0.5 h; then the material enters a twin-screw extruder for melt-extrusion granulation, the melt-extrusion temperature is 200 °C, the extruded spline is cooled at about 20 °C and then enters a pelletizer for pelletizing, and the pellets are packed and packaged, which is the required polyethylene resin product;

[0097] Among them, the formula is as follows: the degree of polymerization of PVA is 1700, the degree of alcoholysis is 88 mol%, and the amount of PVA used is 500 g; the plasticizer is: 40 g of pentaerythritol and 10 g of NP-10; the antioxidant is: 1.5 g of antioxidant 686 and 2.5 g of antioxidant 1010; the amount of inorganic filler used is 30 g; component A in the decomposition-resistant agent is 0.05 g of boric acid; component B in the decomposition-resistant agent is 0.4 g of magnesium hydroxide and 2 g of calcium stearate.

[0098] Example 8

[0099] Mix, heat-insulate, melt-extrude, and cool the polyvinyl alcohol composition according to the following formula to obtain a polyethylene resin. Among them, the mixing is carried out by physical mixing at 400 r / min and 70 °C for 0.5 h, and heat-insulated at 70 °C for 0.5 h; then the material enters a twin-screw extruder for melt-extrusion granulation, the melt-extrusion temperature is 200 °C, the extruded spline is cooled at about 20 °C and then enters a pelletizer for pelletizing, and the pellets are packed and packaged, which is the required polyethylene resin product;

[0100] Among them, the formula is as follows: the degree of polymerization of PVA is 1700, the degree of alcoholysis is 88 mol%, and the amount of PVA used is 500 g; the plasticizer is: 40 g of pentaerythritol and 10 g of NP-10; the antioxidant is: 3 g of antioxidant 686 and 3 g of antioxidant 1010; the amount of inorganic filler used is 30 g; component A in the decomposition-resistant agent is 0.05 g of boric acid; component B in the decomposition-resistant agent is 0.01 g of magnesium hydroxide and 2 g of calcium stearate.

[0101] Example 9

[0102] Mix, heat-insulate, melt-extrude, and cool the polyvinyl alcohol composition according to the following formula to obtain a polyethylene resin. Among them, the mixing is carried out by physical mixing at 400 r / min and 70 °C for 0.5 h, and heat-insulated at 70 °C for 0.5 h; then the material enters a twin-screw extruder for melt-extrusion granulation, the melt-extrusion temperature is 200 °C, the extruded spline is cooled at about 20 °C and then enters a pelletizer for pelletizing, and the pellets are packed and packaged, which is the required polyethylene resin product;

[0103] Among them, the formula is as follows: the degree of polymerization of PVA is 2000, the degree of alcoholysis is 72 mol%, and the dosage of PVA is 500 g; the plasticizer is: 40 g of pentaerythritol and 10 g of NP-10; the antioxidant is: 1.5 g of antioxidant 686 and 2.5 g of antioxidant 1010; the dosage of inorganic filler is 30 g; component A of the decomposition-resistant agent is 0.05 g of boric acid; component B of the decomposition-resistant agent is 0.01 g of magnesium hydroxide and 2 g of calcium stearate.

[0104] Example 10

[0105] Mix, heat-insulate it according to the following formula of the polyvinyl alcohol composition, and melt-extrude and cool it to obtain a polyethylene resin. Among them, the mixing is carried out by physical mixing at 400 r / min and 70 °C for 0.5 h, and heat-insulated at 70 °C for 0.5 h; then the material enters a twin-screw extruder for melt-extrusion granulation, the melt-extrusion temperature is 200 °C, the extruded spline is cooled at about 20 °C and then enters a pelletizer for pelletizing, and the particles are packaged for packaging, which is the required polyethylene resin product;

[0106] Among them, the formula is as follows: the degree of polymerization of PVA is 1700, the degree of alcoholysis is 88 mol%, and the dosage of PVA is 500 g; the plasticizer is: 40 g of pentaerythritol and 10 g of NP-10; the antioxidant is: 4 g of antioxidant 686; the dosage of inorganic filler is 30 g; component A of the decomposition-resistant agent is 0.05 g of boric acid; component B of the decomposition-resistant agent is 0.01 g of magnesium hydroxide and 2 g of calcium stearate.

[0107] Comparative Example 1

[0108] Mix, heat-insulate it according to the following formula of the polyvinyl alcohol composition, and melt-extrude and cool it to obtain a polyethylene resin. Among them, the mixing is carried out by physical mixing at 400 r / min and 70 °C for 0.5 h, and heat-insulated at 70 °C for 0.5 h; then the material enters a twin-screw extruder for melt-extrusion granulation, the melt-extrusion temperature is 200 °C, the extruded spline is cooled at about 20 °C and then enters a pelletizer for pelletizing, and the particles are packaged for packaging, which is the required polyethylene resin product;

[0109] Among them, the composition formula is: the degree of polymerization of PVA is 1700, the degree of alcoholysis is 88 mol%, the dosage is 500 parts, pentaerythritol is 40 parts, and NP-10 is 10 parts.

[0110] Comparative Example 2

[0111] Mix, heat-insulate, melt-extrude and cool the following polyvinyl alcohol composition to obtain a polyethylene resin. Among them, the mixing is carried out by physical mixing at 400 r / min and 70 °C for 0.5 h, and heat-insulated at 70 °C for 0.5 h; then the material enters a twin-screw extruder for melt-extrusion granulation, the melt-extrusion temperature is 200 °C, the extruded spline is cooled at about 20 °C and then enters a pelletizer for pelletizing, and the particles are packed and packaged, which is the required polyethylene resin product;

[0112] Among them, the composition formula is as follows: the degree of polymerization of PVA is 1700, the degree of alcoholysis is 88 mol%, and the dosage of PVA is 500 g; the plasticizer is: 40 g of pentaerythritol and 10 g of NP-10; the antioxidant is: 1.5 g of antioxidant 686 and 2.5 g of antioxidant 1010; the dosage of inorganic filler talcum powder is 30 g.

[0113] Comparative Example 3

[0114] Mix, heat-insulate, melt-extrude and cool the following polyvinyl alcohol composition to obtain a polyethylene resin. Among them, the mixing is carried out by physical mixing at 400 r / min and 70 °C for 0.5 h, and heat-insulated at 70 °C for 0.5 h; then the material enters a twin-screw extruder for melt-extrusion granulation, the melt-extrusion temperature is 200 °C, the extruded spline is cooled at about 20 °C and then enters a pelletizer for pelletizing, and the particles are packed and packaged, which is the required polyethylene resin product;

[0115] Among them, the composition formula is as follows: the degree of polymerization of PVA is 1700, the degree of alcoholysis is 88 mol%, and the dosage of PVA is 500 g; the plasticizer is: 40 g of pentaerythritol and 10 g of NP-10; the antioxidant is: 1.5 g of antioxidant 686 and 2.5 g of antioxidant 1010; the dosage of inorganic filler talcum powder is 30 g; 2.06 g of magnesium hydroxide.

[0116] Comparative Example 4

[0117] Mix, heat-insulate, melt-extrude and cool the following polyvinyl alcohol composition to obtain a polyethylene resin. Among them, the mixing is carried out by physical mixing at 400 r / min and 70 °C for 0.5 h, and heat-insulated at 70 °C for 0.5 h; then the material enters a twin-screw extruder for melt-extrusion granulation, the melt-extrusion temperature is 200 °C, the extruded spline is cooled at about 20 °C and then enters a pelletizer for pelletizing, and the particles are packed and packaged, which is the required polyethylene resin product;

[0118] The degree of polymerization of PVA is 1700, the degree of alcoholysis is 88 mol%, and the amount of PVA used is 500 g; the plasticizer is: 40 g of pentaerythritol and 10 g of NP-10; the antioxidant is: 1.5 g of antioxidant 686 and 2.5 g of antioxidant 1010; the amount of inorganic filler talc used is 30 g; component A of the decomposition-resistant agent is 0.01 g of boric acid; component B of the decomposition-resistant agent is 0.01 g of magnesium hydroxide and 0.1 g of calcium stearate.

[0119] Comparative Example 5

[0120] Mix, keep warm, melt-extrude and cool it according to the following formula of the polyvinyl alcohol composition to obtain a polyethylene resin. Among them, the mixing is carried out at 400 r / min and 70 °C for physical mixing for 0.5 h and kept warm at 70 °C for 0.5 h; then the material enters a twin-screw extruder for melt-extrusion granulation. The melt-extrusion temperature is 200 °C. The extruded spline is cooled at about 20 °C and then enters a pelletizer for pelletizing. The particles are packed and packaged, which is the required polyethylene resin product;

[0121] The formula is as follows: The degree of polymerization of PVA is 1700, the degree of alcoholysis is 88 mol%, and the amount of PVA used is 500 g; the plasticizer is: 40 g of pentaerythritol and 10 g of NP-10; the antioxidant is: 1.5 g of antioxidant 686 and 2.5 g of antioxidant 1010; the amount of inorganic filler talc used is 30 g; the decomposition resistance is 2.06 g of boric acid.

[0122] Comparative Example 6

[0123] Among them, the formula is as follows: The degree of polymerization of PVA is 1700, the degree of alcoholysis is 88 mol%, and the amount of PVA used is 500 g; the plasticizer is: 40 g of pentaerythritol and 10 g of NP-10; the antioxidant is: 1.5 g of antioxidant 686 and 2.5 g of antioxidant 1010; the amount of inorganic filler talc used is 30 g; the decomposition-resistant agent is 0.05 g of boric acid and 2.01 g of magnesium hydroxide.

[0124] Test Example 1

[0125] Test the mechanical properties, maximum decomposition temperature, melt index and dissolution in 10 min of the polyvinyl alcohol resins prepared in the examples and comparative examples. The results are shown in Table 1.

[0126] Table 1

[0127]

[0128] It can be seen from the results in Table 1 that Examples 1-10 of the present invention have the characteristics of high melt index, high tensile strength and impact strength, strong high-temperature resistance and good solubility. Among them, the melt index is not less than 8 g / 10 min-1 Meanwhile, the maximum decomposition temperature is not lower than 290 °C, the tensile strength is not lower than 70 MPa, and the impact strength is not lower than 1.2 kJ / m 2 .

[0129] Among them, the preferred Examples 1-4 have significantly better effects, with a melt index not lower than 18 g / 10 min -1 , meanwhile, the maximum decomposition temperature is not lower than 310 °C, the tensile strength is not lower than 85 MPa, and the impact strength is not lower than 2.4 kJ / m 2 .

[0130] From Figure 1 it can be seen that comparing Example 1 with Comparative Example 1, when the formulation of the composition meets the preferred dosages and the masses of combination A and component B in the decomposition-resistant agent meet the preferred ranges (Example 1), the maximum decomposition temperature of the prepared polyvinyl alcohol resin is significantly higher than that when the formulation of the composition is not within the scope required by the present invention (Comparative Example 1), and the maximum decomposition temperature can reach above 321 °C.

[0131] Test Example 2

[0132] To further illustrate the high-temperature stability of the present invention, the polyvinyl alcohol resins prepared in the examples and comparative examples were kept at 200 °C for 5 h, and then their mechanical properties were tested. The results are shown in Table 2. Among them, the tensile strength decline rate is calculated according to the following formula: tensile strength decline rate = (tensile strength before heat preservation - tensile strength after heat preservation) / tensile strength before heat preservation × 100%. The calculation method of the impact strength decline rate is the same as above.

[0133] Table 2

[0134]

[0135]

[0136] From the above results, it can be seen that the polyvinyl alcohol resins prepared in the examples of the present invention have good high-temperature stability. Among them, the decline rate of the tensile strength is not higher than 4.2%, and the decline rate of the impact strength is not higher than 15%.

[0137] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A polyvinyl alcohol composition, characterized in that, the polyvinyl alcohol composition comprises: 50 - 90 wt% of polyvinyl alcohol, 5 - 15 wt% of a plasticizer, 0.001 - 10 wt% of an antioxidant, 1 - 10 wt% of an inorganic filler, and 0.01 - 5 wt% of a decomposition-resistant agent; wherein, the decomposition-resistant agent contains component A and component B; component A is selected from at least one of boric acid, zinc sulfate, titanium dioxide, tartaric acid, and maleic acid; component B is selected from at least two of magnesium hydroxide, calcium stearate, and potassium dihydrogen phosphate.

2. The polyvinyl alcohol composition according to claim 1, wherein, the polyvinyl alcohol composition comprises: 80 - 90 wt% of polyvinyl alcohol, 6.5 - 12 wt% of a plasticizer, 0.6 - 0.8 wt% of an antioxidant, 5 - 6 wt% of an inorganic filler, and 0.2 - 0.35 wt% of a decomposition-resistant agent; preferably, the mass ratio of component A to component B is 1:10 - 50, preferably 1:15 - 42.

3. The polyvinyl alcohol composition according to claim 1 or 2, wherein, the degree of polymerization of the polyvinyl alcohol is 300 - 2400, preferably 400 - 2000, more preferably 500 - 1700; the degree of alcoholysis of the polyvinyl alcohol is DA, 72 mol% ≤ DA ≤ 99 mol%.

4. The polyvinyl alcohol composition according to any one of claims 1 - 3, wherein, the plasticizer is selected from at least one of pentaerythritol, trimethylolpropane, alkyl polyglycoside, and nonylphenol polyoxyethylene ether; preferably, the antioxidant is selected from at least one of phosphite antioxidants, hindered phenol antioxidants, and aromatic amine antioxidants; preferably, the antioxidant is selected from at least two of antioxidant 686, antioxidant 1010, antioxidant 697, antioxidant 1098, and antioxidant B215; preferably, the inorganic filler is selected from at least one of talc powder, kaolin, and nano calcium carbonate.

5. A method for preparing a polyvinyl alcohol resin, characterized in that, the method comprises: S1. Mixing the polyvinyl alcohol composition according to any one of claims 1 - 4 and optionally performing heat preservation; S2. Melting and extruding the material in step S1 and cooling to obtain a polyvinyl alcohol resin.

6. The method according to claim 5, wherein, the conditions for mixing include: a rotation speed of 300 - 600 r / min and a temperature of 70 - 75 °C; preferably, the conditions for heat preservation include: a temperature of 25 - 90 °C, preferably 70 - 75 °C, and a time of 0 - 10 h, preferably 0.5 - 1 h.

7. The method according to claim 5 or 6, wherein, in step S2, the temperature for melting and extruding is 120 - 220 °C, preferably 190 - 200 °C; the rotation speed is 20 - 500 rpm, preferably 150 - 250 rpm; preferably, the temperature for cooling is 15 - 40 °C, preferably 20 - 30 °C.

8. A polyvinyl alcohol resin prepared by the method according to any one of claims 5 - 7.

9. The polyvinyl alcohol resin according to claim 8, wherein, The maximum decomposition temperature of the polyvinyl alcohol resin is ≥260 °C, preferably ≥290 °C, more preferably ≥310 °C.

10. Application of the polyvinyl alcohol resin according to claim 8 or 9 in at least one of the fields of flexible packaging, toys, vehicle parts, and electrical accessories.

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