Specialized polyhydroxyalkanoate coating material and composite material

Abstract

The present invention provides a specialized polyhydroxyalkanoate coating material and a composite material. A resin raw material in the specialized polyhydroxyalkanoate coating material comprises a rigid component and a flexible component, wherein the rigid component and / or the flexible component comprises a copolymer containing an HV monomer. In the present invention, the resin raw material further comprises the copolymer containing the HV monomer in addition to the rigid component and / or the flexible component, so that the rigidity, the toughness and the adhesion can be balanced as well as possible. The present invention takes into account both the anti-sticking properties of polyhydroxyalkanoate to rollers and good adhesion to paper.

Description

A special coating material and composite material for polyhydroxyalkanoate

[0001] Cross-references

[0002] This application claims priority to Chinese Patent Application No. 2023118226641, filed on December 27, 2023, entitled “A Special Coating Material and Composite Material for Polyhydroxyalkanoate,” all disclosures of which are incorporated herein by reference in their entirety. Technical Field

[0003] The present invention relates to the field of biodegradable materials, in particular to a special coating material and composite material for polyhydroxyalkanoate. Background Art

[0004] Laminating is a coating method that uses a laminating machine to spray hot-melt resin onto the substrate to form a coating, that is, a surface protective film, which can play a role in waterproofing, moisture-proofing, and anti-oxidation.

[0005] The base materials for lamination include paper, aluminum foil, oriented polypropylene, polyester, nylon and high-density polyethylene. Paper is the most commonly used base material, which can be used to obtain paper-plastic composite materials, which can be used to produce sturdy and durable milk cartons, frozen food containers and paper cups.

[0006] Regarding hot-melt resins, polyethylene (PE) and polylactic acid (PL) are currently the most commonly used. PE coatings utilize PE with long and short molecular chain branches and low crystallinity. The numerous branches disrupt the regularity of the molecular structure, reducing crystallinity; the entanglement of long and short branches results in higher melt strength. However, polyethylene is a petrochemical-based material, and the resin coating is non-degradable, potentially polluting the environment. PLA coatings have three stereochemical configurations: dextrorotatory PLA, levorotatory PLA, and meso PLA. Dextrorotatory and levorotatory PLA are optically active, stereoregular polymers with crystallinity levels of approximately 60%. Meso PLA is an amorphous, non-crystalline material. Because its meso structure disrupts the regularity of the molecular chain, it cannot crystallize and does not become brittle due to post-crystallization. While PLA is biodegradable, its degradation requires specific conditions: elevated temperatures of 50-70°C, high humidity, and a high concentration of microorganisms, making its degradation conditions demanding. Furthermore, the carbonyl groups in the PLA molecular chain are coplanar with the adjacent oxygen atoms and very close to the adjacent carbon atoms, making them difficult to rotate. This results in low crystallinity, and the presence of pendant methyl groups results in large molecular distances. This results in poor barrier properties to oxygen and water vapor, making it inadequately protective for oily foods when used in packaging. Furthermore, while PLA and PE coatings offer good results, they suffer from poor resizing properties and are difficult to break.

[0007] Polyhydroxyalkanoates (PHA), a purely bio-sourced, 100% biodegradable emerging material, are more environmentally friendly and bio-friendly in production, purification, and application compared to biodegradable materials such as PLA, polybutylene succinate (PBS), polybutylene adipate / terephthalate (PBAT), and polypropylene carbonate (PPC). They do not require petroleum-based industrial products as a synthetic source, and their degradation requirements are lower. They can naturally degrade without composting, and paper-plastic composites made from PHAs do not cause environmental pollution. However, PHAs have drawbacks when used for laminating, such as sticking to rollers, cracking, and bubbles. Summary of the Invention

[0008] In view of the shortcomings of the existing technology, the present invention provides a special coating material and composite material for polyhydroxyalkanoate, which is environmentally friendly and solves the defects of polyhydroxyalkanoate such as easy sticking to rollers and prone to breakage and bubbles.

[0009] In a first aspect, the present invention provides a polyhydroxyalkanoate coating material, wherein the resin raw material comprises a rigid component and a flexible component, and the rigid component and / or the flexible component comprises a copolymer containing an HV monomer.

[0010] Existing polyhydroxyalkanoates used for coating have the following drawbacks: ① A narrow processing window and poor heat resistance, with severe pyrolysis above 170°C, close to the melting temperature (Tm = 165°C). ② A low crystallization rate and a long post-crystallization period, which can cause brittle products due to post-crystallization. Furthermore, polyhydroxyalkanoates in a viscous flow state tend to stick to rollers. ③ Low melt strength makes coating prone to defects such as breakage and bubbles, affecting product appearance and performance. ④ Polyhydroxyalkanoates have a high degree of crystallinity, making it difficult for molecular chains to diffuse and entangle with each other, resulting in low surface tension and poor adhesion to paper.

[0011] In response to the above problems, the present invention has found that the use of resin raw materials including rigid components and flexible components can take into account both rigidity and plasticity and improve processability. In addition, the present invention has unexpectedly found that HV monomers (including 3HV, 5HV, etc.) help to increase adhesion. By regulating the proportion of each component, the rigidity, toughness and adhesion can be balanced as much as possible, taking into account that the polyhydroxyalkanoate does not stick to the roller and has good adhesion to the paper.

[0012] The above technical solution of the present invention includes three situations: ① only the rigid component includes a copolymer containing HV monomers; ② only the flexible component includes a copolymer containing HV monomers; ③ both the rigid component and the flexible component include copolymers containing HV monomers.

[0013] Preferably, the flexible component accounts for 30-40% by mass in the resin raw material.

[0014] Specifically, when the rigid component includes a copolymer containing an HV monomer, the copolymer containing an HV monomer may be PHBV.

[0015] Furthermore, the polyhydroxyalkanoate containing no HV monomer in the rigid component may be PHB.

[0016] When the flexible component includes a copolymer containing an HV monomer, the copolymer containing an HV monomer may be one or more of P3HB4HB3HV and P3HB4HB5HV.

[0017] Furthermore, the polyhydroxyalkanoate not containing HV monomer in the flexible component may be one or more of P34HB and PHBHHx.

[0018] In some embodiments of the present invention, the resin raw materials in the polyhydroxyalkanoate special coating material include P34HB and PHBV.

[0019] In some embodiments of the present invention, the resin raw materials in the polyhydroxyalkanoate special coating material include PHB and P3HB4HB3HV / P3HB4HB5HV.

[0020] In some embodiments of the present invention, the resin raw materials in the polyhydroxyalkanoate special coating material include PHBV and P3HB4HB3HV / P3HB4HB5HV.

[0021] In some embodiments of the present invention, the resin raw materials in the polyhydroxyalkanoate special coating material include PHB, P34HB and P3HB4HB3HV / P3HB4HB5HV.

[0022] In the above technical solution, it is further preferred that the molar content of 4HB in P34HB is above 15%, and the molecular weight of P34HB is between 200,000 and 400,000 Da.

[0023] The molar content of 3HV in PHBV is 2-10%, and can be any value therein, such as 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%. The molecular weight of PHBV is above 500,000 Da.

[0024] The molecular weight of PHB is above 500,000 Da.

[0025] The molecular weight of P3HB4HB3HV is between 200,000 and 500,000 Da, wherein the molar content of 3HV is 2-10%, and can be any value therein, such as 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, and the molar content of 4HB is above 15%.

[0026] The molecular weight of P3HB4HB5HV is between 200,000 and 500,000 Da, wherein the molar content of 5HV is 2-10%, and can be any value therein, such as 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, and the molar content of 4HB is above 15%.

[0027] The molecular weight of PHBHHx is between 200,000 and 400,000 Da, and the molar content of HHx is above 15%.

[0028] In order to further improve the performance of the polyhydroxyalkanoate coating material, its raw materials may further include one or more of a nucleating agent, a chain extender, an antioxidant and a lubricant.

[0029] In some embodiments of the present invention, the polyhydroxyalkanoate coating material further includes a nucleating agent and a chain extender.

[0030] Increasing the crystallization rate also helps solve the roller sticking problem. Therefore, to increase the crystallization rate, a nucleating agent is added. In some embodiments of the present invention, to avoid affecting transparency, the nucleating agent is selected from one or more of aromatic phosphate salts, sodium cinnamate, metal phosphate salts, basic metal phosphates, and sorbitol benzyl derivatives.

[0031] A chain extender is a substance that reacts with functional groups on a linear polymer chain to extend the molecular chain and increase the molecular weight. In some embodiments of the present invention, the chain extender is selected from one or more of BASF ADR 4400, BASF ADR 4468, chain extender DX-5, chain extender 6901, chain extender MSA7200, and chain extender HER.

[0032] In the polyhydroxyalkanoate coating material of the present invention, the nucleating agent, the chain extender and the polyhydroxyalkanoate having a plasticizing effect have a synergistic effect, which can shorten the molding process cycle and increase the crystallization rate while also improving the toughness of the coating layer without the need for adding a specific toughening agent.

[0033] In some embodiments of the present invention, in order to improve thermal processing stability, the polyhydroxyalkanoate coating material further includes an antioxidant and a lubricant.

[0034] The addition of an antioxidant can prevent the thermal decomposition of polyhydroxyalkanoates. In some embodiments of the present invention, the antioxidant includes a hindered phenol and a thioether antioxidant. The combination of hindered phenol and thioether antioxidants can produce a synergistic effect, and antioxidants with low melting points are preferred.

[0035] Specifically, in some embodiments of the present invention, the hindered phenol antioxidant is selected from one or more common hindered phenol antioxidants such as pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris(2,4-di-tert-butylphenyl) phosphite, and antioxidant CYANOX 1790. The thioether antioxidant is selected from one or more common thioether antioxidants such as distearyl thiodipropionate, didodecyl thiodipropionate, and pentaerythritol tetrakis(3-laurylthiopropionate).

[0036] Furthermore, the present invention has found that the degradation of polyhydroxyalkanoates is significantly affected by shear rate. To achieve high-speed production, a lubricant is added to polyhydroxyalkanoates to reduce frictional heat generated between the screw and molecules, thereby improving stability. In some embodiments of the present invention, the lubricant includes ethylene bisstearamide.

[0037] The auxiliary agent of the present invention is selected to be non-toxic or low-toxic, thereby reducing pollution to the environment and human body, so that the obtained product can be used for food contact packaging.

[0038] In addition, in order to increase the melt strength, the present invention further controls the melt index of the polyhydroxyalkanoate to be between 5-9 g / 10 min.

[0039] In a second aspect, the present invention provides a composite material.

[0040] The composite material provided by the present invention is prepared from a base material and the above-mentioned polyhydroxyalkanoate special laminating material through a laminating process.

[0041] The substrate may be paper, aluminum foil, stretched polypropylene, polyester, nylon, high-density polyethylene, and the like.

[0042] In some embodiments of the present invention, the substrate is paper, that is, the obtained paper-plastic composite material, and since the coating is polyhydroxyalkanoate, the paper-plastic composite material provided by the present invention is a biodegradable composite material.

[0043] The polyhydroxyalkanoate coating layer of the present invention has a high degree of crystallinity and a certain degree of brittleness, but it does not affect the use and can be broken during re-slurrying, that is, re-slurry recovery, with a re-slurry rate of more than 90%.

[0044] The paper of the present invention can be conventional paper in the art, such as white cardboard, grey board, coated paper, offset paper, corrugated paper, writing paper, kraft paper, newsprint, etc. In the embodiment of the present invention, the paper used is white cardboard.

[0045] In some embodiments of the present invention, in order to prevent hydrolysis during processing, the polyhydroxyalkanoate coating material is dried to a moisture content of less than 0.02% before coating. Preferably, the drying condition is vacuum drying at 60-80°C.

[0046] In some embodiments of the present invention, during the coating process, in order to prevent degradation of the polyhydroxyalkanoate during processing, the melt processing temperature is set within the melting point of the polyhydroxyalkanoate coating material ± 10 ° C, and the screw speed is 120-150 rpm. Under these conditions, the molecular weight of the polyhydroxyalkanoate is reduced to a small extent (the original molecular weight is 600,000-800,000, and the processed molecular weight is between 480,000-600,000). The temperature of the pulling roller is set within the range of 60-80 ° C. Heating the pulling roller can cause the side of the polyhydroxyalkanoate coating material in contact with the pulling roller to quickly crystallize, reducing adhesion to the pulling roller.

[0047] The polyhydroxyalkanoate coating layer obtained by the present invention has a heat deformation temperature greater than 90° C., is suitable for containing cold water and hot water, and has better barrier properties than PLA coating.

[0048] In some embodiments of the present invention, after obtaining the laminated paper, in the heat sealing step, the heat sealing temperature is controlled between 250-310° C., the heat sealing time is controlled between 0.1-0.5 seconds, and the laminate weight is controlled between 25-30 gsm.

[0049] The present invention has found that excessively high temperatures and prolonged heat sealing times can cause polyhydroxyalkanoates to degrade, causing a sharp drop in molecular weight and affecting heat seal strength. Furthermore, a coating weight of 25-30 gsm offers better heat sealing performance than a coating weight of 15-24 gsm.

[0050] The present invention provides a polyhydroxyalkanoate coating material and composite material. By regulating the composition of the polyhydroxyalkanoate system, the coating material can achieve a good balance between rigidity, toughness, and adhesion, ensuring that the polyhydroxyalkanoate does not stick to rollers and has good adhesion to paper. Furthermore, the polyhydroxyalkanoate coating material of the present invention is made from bio-based, biodegradable materials. Compared to coatings such as PLA, PE, and PP, the coating layer is more easily degraded in the natural environment, eliminating the need for composting. Its excellent biodegradability has no negative impact on the environment, contributing to addressing the plastic crisis. DETAILED DESCRIPTION

[0051] The term "include" or "comprising" in the present invention is an open description containing the specified components or steps described, as well as other specified components or steps that do not substantially affect them.

[0052] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0053] In the description of this specification, the reference terms "one embodiment", "some embodiments", "specific implementation methods", or "some specific implementation methods" and the like mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0054] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0055] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased through regular channels.

[0056] The Chinese full names of the English abbreviations appearing in this article are as follows: PHA: polyhydroxyalkanoate PLA: polylactic acid PBS: polybutylene succinate PBAT: polybutylene adipate / terephthalate PPC: polypropylene carbonate PHB: poly-3-hydroxybutyrate P4HB: poly-4-hydroxybutyrate P3HP: poly-3-hydroxypropionate PHBV: poly(3-hydroxybutyrate-co-3-hydroxyvalerate) P34HB: poly(3-hydroxybutyrate-co-4-hydroxybutyrate) PHBHHx: poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) P3HB4HB3HV: poly(3-hydroxybutyrate-co-4-hydroxybutyrate-co-3-hydroxyvalerate) P3HB4HB5HV: poly(3-hydroxybutyrate-co-4-hydroxybutyrate-co-5-hydroxyvalerate) TEPA: triethyl phosphate EBS: ethylene bisstearamide Antioxidant CA: 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane Antioxidant 1010: pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] Antioxidant BHT: 2,6-di-tert-butyl-4-methylphenol Antioxidant 1098: N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyphenylpropionamide) Antioxidant 245: triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate] Antioxidant PEPQ: Tetrakis (2,4-di-tert-butylphenol) 4,4'-biphenyl diphosphite Antioxidant 168: Tris (2,4-di-tert-butylphenyl) phosphite Antioxidant DSTP: Distearyl thiodipropionate (thioethers) melting point 63-68°C Antioxidant DLTP: Didodecyl thiodipropionate (thioethers) melting point 39-42°C Free radical inhibitor: 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl free radical (melting point 69-72°C) Antioxidant 412s: Pentaerythritol tetrakis (3-laurylthiopropionate) melting point 48-54°C.

[0057] Example 1

[0058] This embodiment provides a polyhydroxyalkanoate coating material, wherein the resin raw materials are composed of P34HB (amorphous with a 4HB molar content of more than 15%, and a molecular weight of 200,000-400,000 Da) and PHBV (3HV molar content of 3%, and a molecular weight of more than 500,000 Da). The specific preparation method is as follows:

[0059] Step 1: Dry the P34HB and PHBV raw materials in a vacuum at 60-80°C for 4 hours to control the moisture content below 500 ppm;

[0060] Step 2: Weigh 30 parts of P34HB, 70 parts of PHBV, 0.3 parts of calcium laurate, 0.5 parts of nano-calcium carbonate, 0.4 parts of Joncryl ADR-4400, 0.2 parts of antioxidant 245, 0.2 parts of antioxidant 412s, 0.4 parts of carbodiimide, 0.5 parts of montanic acid glycol ester, 0.5 parts of EBS and 2 parts of epoxy soybean oil, and mix them in a high-speed mixer for 5 minutes. Then, granulate them through a twin-screw extruder. The temperature settings of each section are: feeding section 150°C, compression section 160°C, homogenization section 170°C, die head 175°C, main engine speed 200rpm, feeding rate 10Hz, and then water-cooled and air-dried and granulated to obtain a special coating material for polyhydroxyalkanoate.

[0061] This embodiment also uses the polyhydroxyalkanoate special coating material obtained above to prepare a paper-plastic composite material, and the specific method is as follows:

[0062] Add the polyhydroxyalkanoate special laminating material into the laminating machine, set the melt processing temperature to 160-200℃, the screw speed to 120rpm, the temperature of the pulling roller 1 and the pulling roller 2 to between 60-80℃, and the extrusion die head between the pulling roller 1 and the pulling roller 2. The material flows out of the die head and is compounded with the paper to prepare a paper-plastic composite material.

[0063] Based on Example 1, the molar content of 3HV in PHBV was adjusted to 2%, 4%, 5%, 7%, 8%, and 10%, respectively, while the other conditions remained unchanged. Parallel experiments were carried out. The results showed that when the molar content of 3HV in PHBV was within the range of 2-10%, the effect comparable to that of Example 1 could be achieved, and a polyhydroxyalkanoate special coating material and paper-plastic composite material with good performance were obtained.

[0064] Example 2

[0065] This embodiment provides a polyhydroxyalkanoate coating material, wherein the resin raw materials are composed of P3HB4HB3HV (3HB molar content of 80%, 3HV molar content of 3%, molecular weight of 200,000-500,000 Da) and PHB (molecular weight of 500,000 Da or more). The specific preparation method is as follows:

[0066] Step 1: Dry the P3HB4HB3HV and PHB raw materials in a vacuum at 60-80°C for 4 hours to control the moisture content below 500ppm;

[0067] Step 2: Weigh 30 parts of P3HB4HB3HV, 70 parts of PHB, 0.3 parts of calcium laurate, 0.5 parts of nano-calcium carbonate, 0.4 parts of BASF ADR-4400, 0.2 parts of antioxidant 245, 0.2 parts of antioxidant 412s, 0.4 parts of carbodiimide, 0.5 parts of montanic acid glycol ester, 0.5 parts of EBS and 2 parts of epoxidized soybean oil, and mix them by high-speed mixer for 5 minutes, and then granulate them by twin-screw extruder. The temperature settings of each section are: feeding section 150°C, compression section 160°C, homogenizing section 170°C, die head 175°C, main engine speed 200rpm, feeding rate 10Hz, and then water-cooled and air-dried and granulated to obtain a special coating material for polyhydroxyalkanoate.

[0068] This embodiment also uses the polyhydroxyalkanoate special coating material obtained above to prepare a paper-plastic composite material, and the specific method is the same as that of Example 1.

[0069] Based on Example 2, the molar content of 3HV in P3HB4HB3HV was adjusted to 2%, 4%, 5%, 7%, 9%, and 10%, respectively, and the other conditions remained unchanged. Parallel experiments were carried out. The results showed that when the molar content of 3HV in P3HB4HB3HV was in the range of 2-10%, the effect equivalent to that of Example 2 could be achieved, and a special polyhydroxyalkanoate coating material and paper-plastic composite material with good performance were obtained.

[0070] Example 3

[0071] This embodiment provides a polyhydroxyalkanoate coating material, wherein the resin raw materials are composed of P3HB4HB3HV (same as in Example 2) and PHBV (same as in Example 1). The specific preparation method is as follows:

[0072] Step 1: Dry the P3HB4HB3HV and PHBV raw materials in a vacuum at 60-80°C for 4 hours to control the moisture content below 500ppm;

[0073] Step 2: Weigh 30 parts of P3HB4HB3HV, 70 parts of PHBV, 0.3 parts of calcium laurate, 0.5 parts of nano-calcium carbonate, 0.4 parts of BASF ADR-4400, 0.2 parts of antioxidant 245, 0.2 parts of antioxidant 412s, 0.4 parts of carbodiimide, 0.5 parts of montanic acid glycol ester, 0.5 parts of EBS and 2 parts of epoxidized soybean oil, and mix them by high-speed mixer for 5 minutes, and then granulate them by twin-screw extruder. The temperature settings of each section are: feeding section 150°C, compression section 160°C, homogenizing section 170°C, die head 175°C, main engine speed 200rpm, feeding rate 10Hz, and then water-cooled and air-dried and granulated to obtain a special coating material for polyhydroxyalkanoate.

[0074] This embodiment also uses the polyhydroxyalkanoate special coating material obtained above to prepare a paper-plastic composite material, and the specific method is the same as that of Example 1.

[0075] Example 4

[0076] This embodiment provides a polyhydroxyalkanoate coating material, wherein the resin raw materials are composed of PHB (same as in Example 2), P34HB (same as in Example 1), and P3HB4HB5HV (3HB molar content of 75%, 5HV molar content of 5%, molecular weight of 200,000-500,000 Da). The specific preparation method is as follows:

[0077] Step 1: Dry the raw materials of PHB, P34HB and P3HB4HB3HV at 60-80℃ under vacuum for 4h to control the moisture content below 500ppm;

[0078] Step 2: Weigh 70 parts of PHB, 15 parts of P34HB, 15 parts of P3HB4HB5HV, 0.3 parts of zinc stearate, 0.5 parts of cyclodextrin, 0.4 parts of BASF ADR-4468, 0.1 parts of antioxidant 1010, 0.2 parts of antioxidant DLTP, 0.5 parts of polymerized carbodiimide, 0.5 parts of EBS and 2 parts of acetyl tributyl citrate, and physically mix them for 15 minutes through a high-speed mixer. Then, melt-extrude and granulate them through a twin-screw extruder. The temperature settings of each section are: feeding section 120°C, compression section 160°C, homogenizing section 170°C, die head 175°C, main engine speed 200rpm, feeding rate 10Hz, and then water-cooled and air-dried and granulated to obtain a special coating material for polyhydroxyalkanoate.

[0079] This embodiment also uses the polyhydroxyalkanoate special coating material obtained above to prepare a paper-plastic composite material, and the specific method is the same as that of Example 1.

[0080] Based on Example 4, the molar content of 5HV in P3HB4HB5HV was adjusted to 2%, 4%, 6%, 7%, 9%, and 10%, respectively, while the other conditions remained unchanged. Parallel experiments were carried out. The results showed that when the molar content of 5HV in P3HB4HB5HV was in the range of 2-10%, the effect equivalent to that of Example 4 could be achieved, and a special polyhydroxyalkanoate coating material and paper-plastic composite material with good performance were obtained.

[0081] Performance Testing

[0082] The performance test of the polyhydroxyalkanoate coating material obtained in each embodiment was carried out, and the test methods of each index are as follows:

[0083] 1. Melt index determination

[0084] The melt mass flow rate is carried out in accordance with GB / T 3682.1, the test temperature is 190°C, and the nominal load is 2.16 kg.

[0085] 2. Tensile strength determination

[0086] The test was carried out in accordance with GB / T 1040.2-2006, using A1 type specimens at a test speed of 50 mm / min.

[0087] 3. Determination of elongation at break

[0088] The test was carried out in accordance with GB / T 1040.2-2006, using A1 type specimens at a test speed of 50 mm / min.

[0089] 4. Determination of Izod Notched Impact Strength

[0090] The test was carried out in accordance with GB / T 1843-2008, using B1 type specimen, single notch, notch type C.

[0091] 5. Determination of heat deformation temperature

[0092] The heat deformation temperature (HDT) is carried out in accordance with GB / T 1634-2004, and the test pressure is 0.455MPa.

[0093] The test results are shown in Table 1.

[0094] Table 1

[0095] The paper-plastic composite materials obtained in each example were also subjected to a hot coffee test. This test involved forming a container with the paper-plastic composite material and filling it with hot coffee (≥95°C) for 30 minutes. The test revealed no cracking or warping at the heat seal on the top edge, and no leakage at the bottom or heat seal. After pouring out the coffee, no leakage was observed inside the container.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention. Industrial Applicability

[0097] The present invention provides a polyhydroxyalkanoate coating material and composite material. The resin raw material of the polyhydroxyalkanoate coating material includes a rigid component and a flexible component, and the rigid component and / or the flexible component include a copolymer containing an HV monomer. In addition to the rigid and flexible components, the present invention also includes a copolymer containing an HV monomer. This material achieves a good balance between rigidity, toughness, and adhesion, ensuring that the polyhydroxyalkanoate does not stick to rollers while also exhibiting good adhesion to paper. The material has good economic value and application prospects.

Claims

1. A special polyhydroxyalkanoate coating material, characterized in that, The resin raw material includes a rigid component and a flexible component, and the rigid component and / or the flexible component includes a copolymer containing HV monomers.

2. The polyhydroxyalkanoate special coating material according to claim 1, characterized in that The mass percentage of the flexible component in the resin raw material is 30-40%.

3. The polyhydroxyalkanoate special lamination material according to claim 1 or 2, characterized in that, In the rigid component, the copolymer containing HV monomers is selected from PHBV, its molecular weight is greater than 500,000 Da, and the molar content of 3HV is 2-10%.

4. The polyhydroxyalkanoate special coating material according to claim 3, characterized in that, In the rigid component, the polyhydroxyalkanoate without HV monomers is selected from PHB, and its molecular weight is greater than 500,000 Da.

5. The polyhydroxyalkanoate special coating material according to claim 1 or 2, characterized in that, In the flexible component, the copolymer containing HV monomers is selected from P3HB4HB3HV and P3HB4HB5HV, with a molecular weight between 200,000 and 500,000 Da, where the molar content of 3HV or 5HV is 2-10%, and the molar content of 4HB is more than 15%.

6. The polyhydroxyalkanoate special lamination material according to claim 5, characterized in that In the flexible component, the polyhydroxyalkanoate without HV monomers is selected from P34HB and PHBHHx, with a molecular weight between 200,000 and 400,000 Da, where the molar content of 4HB or HHx is more than 15%.

7. The polyhydroxyalkanoate special lamination material according to any one of claims 1-6, characterized in that The special polyhydroxyalkanoate film laminating material further includes one or more of a nucleating agent, a chain extender, an antioxidant, and a lubricant; Preferably, the nucleating agent is selected from one or more of aromatic phosphate salts, sodium cinnamate, metal phosphate salts, basic metal phosphates, and sorbitol benzylidene derivatives; The chain extender is selected from one or more of BASF ADR 4400, BASF ADR 4468, chain extender DX-5, chain extender 6901, chain extender MSA7200, and chain extender HER; The antioxidant includes hindered phenols and thioether antioxidants; The lubricant includes ethylene bisstearamide.

8. A composite material, characterized in that, It is prepared by a film laminating process from a substrate and the special polyhydroxyalkanoate film laminating material according to any one of claims 1-7; Preferably, the substrate is paper.

9. The composite material according to claim 8, wherein Before the film laminating, the special polyhydroxyalkanoate film laminating material is dried to a moisture content of less than 0.02%; Preferably, the drying conditions are vacuum drying at 60-80°C.

10. The composite material according to claim 8 or 9, characterized in that, During the film laminating process, the melting processing temperature is set within the range of ±10°C of the melting point of the special polyhydroxyalkanoate film laminating material, the screw speed is 120-150 rpm, and the temperature of the traction roller is within the range of 60-80°C.

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