A low moisture permeability flexible biodegradable material and preparation method thereof

Abstract

The present invention provides a low moisture permeability flexible biodegradable material and a preparation method thereof, and relates to the technical field of biodegradable materials. The low moisture permeability flexible biodegradable material of the present invention is composed of raw materials such as polyhydroxyalkanoate, polyvinyl alcohol, hydrophobic fumed silica, lanolin magnesium soap, silane coupling agent, erucic acid amide, etc. The low moisture permeability flexible biodegradable material of the present invention is biodegradable and has excellent waterproof and water-blocking properties.

Description

Technical Field

[0001] The invention relates to the technical field of biodegradable materials, and in particular to a low-water vapor permeability flexible biodegradable material and a preparation method thereof. Background Art

[0002] Biodegradable materials are alternative products to olefin-based polymer films that the country has vigorously advocated in recent years. Their excellent degradation performance is of epoch-making significance for solving the white pollution caused by plastic bags, and is an important measure to achieve carbon peak and carbon neutrality in the future. However, at present, whether it is PBAT material or other types of biodegradable materials used for packaging films, there is a problem of poor barrier properties, especially the barrier properties to water molecules, which leads to a high moisture permeability of the material, which is not conducive to use in packaging fields that are sensitive to humidity. The reason for the above problems is that biodegradable materials themselves have more polar groups and are very compatible with water molecules with strong polarity. Water molecules are easier to pass through the film, resulting in a high moisture permeability.

[0003] Therefore, how to significantly reduce the moisture permeability of biodegradable molecules without changing their functional groups and improve their water barrier properties is a technical problem that needs to be solved urgently. Summary of the invention

[0004] To solve the above problems, the present invention provides a low moisture permeability flexible biodegradable material and a preparation method thereof. The present invention improves the water barrier property of the material and reduces the moisture permeability of the material by changing the microstructure of the material without changing the functional groups of the biodegradable molecules themselves. The low moisture permeability flexible biodegradable material of the present invention comprises the following raw materials in percentage by weight:

[0005] Polyhydroxyalkanoate (PHA) 62%-69%, polyvinyl alcohol (PVA) 15%-22%, hydrophobic fumed silica 5%-13%, lanolin magnesium soap 6%-10%, silane coupling agent 1%-3%, erucamide 1%-3%, the sum of the weight percentages of the above raw materials is 100%.

[0006] Furthermore, the low moisture permeability flexible biodegradable material is composed of the following raw materials in percentage by weight: 62% PHA, 20% PVA, 10% hydrophobic fumed silica, 6% lanolin magnesium soap, 1% silane coupling agent, and 1% erucamide.

[0007] Furthermore, the low moisture permeability flexible biodegradable material is composed of the following raw materials in percentage by weight: 66% PHA, 18% PVA, 6% hydrophobic fumed silica, 8% lanolin magnesium soap, 1% silane coupling agent, and 1% erucamide.

[0008] Furthermore, the silane coupling agent is silane coupling agent 570.

[0009] The present invention also provides a method for preparing the low water vapor permeability flexible biodegradable material, which specifically comprises the following steps:

[0010] (1) PVA is crushed to a particle size of 30 mesh and then used for later use;

[0011] (2) kneading the hydrophobic fumed silica and the silane coupling agent by high-speed stirring to obtain a mixture A;

[0012] (3) mixing PHA and crushed PVA particles at high speed to obtain a mixture B;

[0013] (4) adding erucic acid amide to mixture B, stirring evenly, then adding mixture A, stirring for 5 minutes to obtain mixture C;

[0014] (5) adding lanolin magnesium soap to mixture C and continuing stirring for 5 min to obtain mixture D;

[0015] (6) In a twin-screw extruder, the mixture D is extruded and granulated to obtain a flexible biodegradable material with low moisture permeability.

[0016] Furthermore, the stirring speed in step (2) is 1500 r / min and the stirring time is 3 min.

[0017] Furthermore, in step (3), the stirring speed is 1500 r / min and the stirring time is 10 min.

[0018] Furthermore, the extrusion temperature in step (6) is 170°C.

[0019] In the present invention, hydrophobic fumed silica, after being added, can reduce the aggregation of water molecules on the surface and internal pores of the material, reduce the probability of water passing through, and at the same time produce high fluidity and small size effect, fill in the polymer molecular chains, make the material more dense, thereby improving the sealing and impermeability of the material; erucic acid amide can form a hydrophobic layer on the surface of PHA and PVA to improve the hydrophobicity of the material; the original use of lanolin magnesium soap is a rust-proof additive, and its rust-proof principle is water-blocking, so it is used in the present invention to increase the water-blocking function of the surface and internal pores of the material; PHA is the basic material and core of the present invention, and itself It has good gas barrier properties, but due to the presence of active groups on its molecular chain, its moisture permeability is high and it cannot have a good water-blocking effect. Therefore, in order to further reduce its moisture permeability, the present invention adopts a series of auxiliary materials to comprehensively modify it; PVA itself is also a biodegradable material, and its highly polar hydroxyl groups can form partial hydrogen bonds and other intermolecular forces with the abundant active groups on the surface of PHA, further stabilizing the material structure and improving the density of the structure. After surface modification, its hydrophobicity is increased; silane coupling agents can improve the compatibility between various substances and prevent nanomaterial particles from agglomerating.

[0020] Compared with the prior art, the beneficial technical effects of the present invention are:

[0021] The present invention modifies the biodegradable material by selecting and compounding a specific modifier, and significantly reduces the moisture permeability of the material and improves the water barrier property of the material without changing the functional groups of the biodegradable molecules themselves. DETAILED DESCRIPTION

[0022] The present invention provides a low moisture permeability flexible biodegradable material comprising the following raw materials in percentage by weight:

[0023] Polyhydroxyalkanoate (PHA) 62%-69%, polyvinyl alcohol (PVA) 15%-22%, hydrophobic fumed silica 5%-13%, lanolin magnesium soap 6%-10%, silane coupling agent 1%-3%, erucamide 1%-3%, the sum of the weight percentages of the above raw materials is 100%.

[0024] In one embodiment, the low moisture permeability flexible biodegradable material is composed of the following raw materials in percentage by weight: 62% PHA, 20% PVA, 10% hydrophobic fumed silica, 6% lanolin magnesium soap, 1% silane coupling agent, and 1% erucamide.

[0025] In one embodiment, the low moisture permeability flexible biodegradable material is composed of the following raw materials in percentage by weight: 66% PHA, 18% PVA, 6% hydrophobic fumed silica, 8% lanolin magnesium soap, 1% silane coupling agent, and 1% erucamide.

[0026] In one embodiment, the silane coupling agent is silane coupling agent 570 .

[0027] The present invention also provides a method for preparing the low water vapor permeability flexible biodegradable material, which specifically comprises the following steps:

[0028] (1) PVA is crushed to a particle size of 30 mesh and then used for later use;

[0029] (2) kneading the hydrophobic fumed silica and the silane coupling agent by high-speed stirring to obtain a mixture A;

[0030] (3) mixing PHA and crushed PVA particles at high speed to obtain a mixture B;

[0031] (4) adding erucic acid amide to mixture B, stirring evenly, then adding mixture A, stirring for 5 minutes to obtain mixture C;

[0032] (5) adding lanolin magnesium soap to mixture C and continuing stirring for 5 min to obtain mixture D;

[0033] (6) In a twin-screw extruder, the mixture D is extruded and granulated to obtain a flexible biodegradable material with low moisture permeability.

[0034] In one embodiment, the stirring speed in step (2) is 1500 r / min and the stirring time is 3 min.

[0035] In one embodiment, the stirring speed in step (3) is 1500 r / min and the stirring time is 10 min.

[0036] In one embodiment, the extrusion temperature in step (6) is 170°C.

[0037] The technical solution provided by the present invention is further described below in conjunction with embodiments.

[0038] The hydrophobic fumed silica in the embodiment of the present invention is of model HL-202N, with a particle size of 20-60 nm, and is produced by Hubei Huifu Nanomaterials Co., Ltd.

[0039] Example 1

[0040] A low water vapor permeability flexible biodegradable material is composed of the following raw materials in percentage by weight:

[0041] PHA69%, PVA15%, hydrophobic fumed silica8%, lanolin magnesium soap6%, silane coupling agent 5701%, erucamide1%.

[0042] The preparation method of the low moisture permeability flexible biodegradable material is as follows: (1) PVA is crushed to a particle size of 30 meshes and set aside; (2) hydrophobic fumed silica and a silane coupling agent are stirred and kneaded at a speed of 1500 r / min for 3 minutes to obtain a mixture A; (3) PHA and the crushed PVA particles are mixed at a speed of 1500 r / min for 10 minutes to obtain a mixture B; (4) erucic acid amide is added to the mixture B and stirred evenly, and then the mixture A is added and stirred for 5 minutes to obtain a mixture C; (5) lanolin magnesium soap is added to the mixture C and stirred for 5 minutes to obtain a mixture D; (6) the mixture D is extruded and granulated at 170° C. in a twin-screw extruder to obtain a low moisture permeability flexible biodegradable material.

[0043] The obtained flexible biodegradable material with low moisture permeability was blown into a film with a thickness of 0.05 mm.

[0044] Example 2

[0045] The same as Example 1, except that the low moisture permeability flexible biodegradable material is composed of the following raw materials in percentage by weight:

[0046] PHA62%, PVA20%, hydrophobic fumed silica10%, lanolin magnesium soap6%, silane coupling agent 5701%, erucamide1%.

[0047] Example 3

[0048] The same as Example 1, except that the low moisture permeability flexible biodegradable material is composed of the following raw materials in percentage by weight:

[0049] PHA 66%, PVA 18%, hydrophobic fumed silica 6%, lanolin magnesium soap 8%, silane coupling agent 5701%, erucamide 1%.

[0050] Comparative Example 1

[0051] Pure PHA granules.

[0052] Comparative Example 2

[0053] The weight percentages of the raw materials are: LDPE222WT 60%, LLDPE704240%.

[0054] Comparative Example 3

[0055] The same as Example 1, except that the weight percentages of the raw materials are: PHA 84%, hydrophobic fumed silica 8%, lanolin magnesium soap 6%, silane coupling agent 5701%, erucamide 1%, and the step of adding PVA is ignored during the preparation.

[0056] Comparative Example 4

[0057] The same as Example 1, except that the weight percentages of the raw materials are: PHA 75%, PVA 15%, hydrophobic fumed silica 8%, silane coupling agent 5701%, erucamide 1%, and the step of adding lanolin magnesium soap is omitted during the preparation.

[0058] Comparative Example 5

[0059] The same as Example 1, except that the weight percentages of the raw materials are: PHA 77%, PVA 15%, lanolin magnesium soap 6%, silane coupling agent 5701%, erucamide 1%, and the step of adding hydrophobic fumed silica is omitted during the preparation.

[0060] Test Example 1

[0061] The pellets obtained in Examples 1 to 3 and Comparative Examples 1 to 5 were blown into films with a thickness of 0.05 mm and then cut into film samples of the same specification and the water vapor transmission rates of the samples were measured.

[0062] The test method of water vapor transmission rate is as follows: take a 100mL beaker, put 1g of highly hygroscopic inorganic salt (sodium sulfate) in it, cover the film sample on the cup mouth, tie it with a rubber band, place the whole device in a constant temperature and humidity chamber, keep the temperature at 35°C and the humidity at 100%RH, and weigh it after natural moisture absorption for 48 hours to obtain the amount of moisture absorbed by the inorganic salt and calculate the water vapor transmission rate.

[0063] The results are as follows:

[0064]

[0065] It can be seen that the film made of the low moisture permeability flexible biodegradable material provided by the present invention has a moisture permeability comparable to that of pure polyethylene film, and is slightly better than that of polyethylene film in some proportions. However, after removing certain components in the composition, the moisture permeability is greatly improved, even higher than that of pure PHA.

[0066] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A flexible biodegradable material with low moisture permeability, characterized in that: The following raw materials are included in weight percentage: Polyhydroxyalkanoate (PHA) 62%~69%, polyvinyl alcohol (PVA) 15%~22%, hydrophobic fumed silica 5%~13%, lanolin magnesium soap 6%~10%, silane coupling agent 1%~3%, erucamide 1%~3%, the sum of the weight percentages of the above raw materials is 100%.

2. The low water vapor permeability flexible biodegradable material according to claim 1, characterized in that: The low moisture permeability flexible biodegradable material is composed of the following raw materials in percentage by weight: 62% PHA, 20% PVA, 10% hydrophobic fumed silica, 6% lanolin magnesium soap, 1% silane coupling agent, and 1% erucamide.

3. The low water vapor permeability flexible biodegradable material according to claim 1, characterized in that: The low moisture permeability flexible biodegradable material is composed of the following raw materials in percentage by weight: 66% PHA, 18% PVA, 6% hydrophobic fumed silica, 8% lanolin magnesium soap, 1% silane coupling agent, and 1% erucamide.

4. The method for preparing the flexible biodegradable material with low water vapor permeability according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) Grind PVA to a particle size of 30 mesh and set aside; (2) kneading the hydrophobic fumed silica and the silane coupling agent under high-speed stirring to obtain a mixture A; (3) mixing PHA and crushed PVA particles at high speed to obtain a mixture B; (4) Add erucic acid amide to mixture B and stir evenly, then add mixture A and stir for 5 minutes to obtain mixture C; (5) Add lanolin magnesium soap to mixture C and continue stirring for 5 min to obtain mixture D; (6) In a twin-screw extruder, the mixture D is extruded and granulated to obtain a flexible biodegradable material with low moisture permeability.

5. The method for preparing a flexible biodegradable material with low water vapor permeability according to claim 4, characterized in that: The stirring speed in step (2) is 1500 r / min and the stirring time is 3 min.

6. The method for preparing a flexible biodegradable material with low water vapor permeability according to claim 4, characterized in that: The stirring speed in the high-speed mixing in step (3) is 1500 r / min, and the stirring time is 10 min.

7. The method for preparing a flexible biodegradable material with low water vapor permeability according to claim 4, characterized in that: The extrusion temperature in step (6) is 170°C.

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