A high stiffness composite packaging material and a process for its production

Abstract

The application relates to the technical field of packaging materials, and discloses a high-stiffness composite packaging material and a production process thereof, wherein the high-stiffness composite packaging material comprises, from bottom to top, a PP non-woven fabric layer, a connecting layer and a printing film layer; the connecting layer is composed of PP particles and PE particles; the printing film is a BOPP film; the PP non-woven fabric layer comprises the following components in parts by weight: 100 parts of polypropylene, 2-5 parts of a nucleating agent, 0.5-1 part of an antioxidant and 0.1-0.3 part of a lubricant; the nucleating agent comprises the following components: silicon dioxide, decanedioic acid diphenyl dihydrazide and zinc octanedioate. Through the technical scheme, the problem that the packaging material has poor stiffness due to the low toughness and strength of the polypropylene non-woven fabric in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of packaging materials technology, specifically to a high-stiffness composite packaging material and its production process. Background Technology

[0002] Polypropylene nonwoven fabric is produced using the principles of chemical fiber spinning. During polymer spinning, continuous filaments are laid into a web, which is then reinforced using methods such as needle punching, hydroentangling, chemical bonding, thermal bonding, or hot air bonding to form a nonwoven fabric. Its production accounts for 60%–70% of the world's total nonwoven fabric production, and its applications are becoming increasingly widespread. In packaging materials, polypropylene nonwoven fabric is often used in combination with other polymer films. However, currently, polypropylene nonwoven fabric still suffers from low toughness and strength, resulting in poor stiffness in packaging materials and consequently affecting the practical needs of packaging materials in society. Summary of the Invention

[0003] This invention proposes a high-stiffness composite packaging material and its production process, which solves the problem of poor stiffness in packaging materials caused by the low toughness and strength of polypropylene nonwoven fabric in related technologies.

[0004] The technical solution of the present invention is as follows:

[0005] This invention proposes a high-stiffness composite packaging material, which, from bottom to top, comprises a PP non-woven fabric layer, a connecting layer, and a printed film layer; the connecting layer comprises PP particles and PE particles; the printed film is a BOPP film.

[0006] The PP nonwoven fabric layer comprises the following components in parts by weight: 100 parts polypropylene, 2-5 parts nucleating agent, 0.5-1 part antioxidant, and 0.1-0.3 parts lubricant;

[0007] The nucleating agent comprises the following components: silicon dioxide, sebacate diphenyl dihydrazide, and zinc octanoate.

[0008] As a further technical solution, the mass ratio of silicon dioxide, sebacic acid diphenyl dihydrazide and zinc octanoate is 5:1:4 to 7:2:1.

[0009] In this invention, the stiffness of the composite packaging material is further improved by adjusting the mass ratio of silicon dioxide, sebacic acid diphenyl dihydrazide and zinc octanoate to 5:1:4~7:2:1.

[0010] As a further technical solution, the silicon dioxide is n-heptanoic acid modified silicon dioxide.

[0011] As a further technical solution, in the n-heptanoic acid modified silica, the mass ratio of n-heptanoic acid to silica is 1:15~20.

[0012] As a further technical solution, the preparation method of the n-heptanoic acid modified silica includes the following steps: dissolving n-heptanoic acid and mixing it with silica, drying it to obtain n-heptanoic acid modified silica.

[0013] In this invention, by using heptanoic acid to modify silica, the stability of silica nucleating agent is improved while its dispersibility in polypropylene matrix is ​​also enhanced. Furthermore, by adding sebacic acid diphenyl dihydrazide and zinc octanoate to PP nonwoven fabric, the stiffness of the composite packaging material is further improved.

[0014] As a further technical solution, the solvent used for dissolution is either ethanol or diethyl ether.

[0015] As a further technical solution, the antioxidant is one or more of phosphite antioxidants and phenolic antioxidants; the lubricant is one or two of polyethylene wax and polypropylene wax.

[0016] As a further technical solution, the thickness of the connecting layer is 10~12μm.

[0017] As a further technical solution, the thickness of the BOPP film is 25~30μm.

[0018] The present invention also proposes a production process for the aforementioned high-stiffness composite packaging material, comprising the following steps:

[0019] S1. The components of the PP nonwoven fabric layer are mixed and then melt-blown and pressed into shape to obtain the PP nonwoven fabric.

[0020] S2. After mixing the components of the connecting layer, the mixture is cast between the PP nonwoven fabric and the BOPP film to form a high-stiffness composite packaging material.

[0021] The working principle and beneficial effects of this invention are as follows:

[0022] 1. In this invention, the high stiffness composite packaging material includes a PP nonwoven fabric layer, a connecting layer, and a printed film layer. By introducing nucleating agents such as silica, sebacic acid diphenyl dihydrazide, and zinc octanoate into the components of the PP nonwoven fabric layer, the three synergistically regulate the crystallinity of polypropylene, improve the defects of existing PP nonwoven fabrics that are not strong and tough, improve the strength and toughness of PP nonwoven fabrics, and significantly improve the stiffness of the composite packaging material. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] In the following examples and comparative examples, the polypropylene was model TF400; the PP granules were model 511M40T; the PE granules were model LD605; the purity of sebacic acid diphenyl dihydrazide and zinc octanoate was 99wt%; the particle size of silica was 60nm; and the CAS number of n-heptanoic acid was 111-14-8.

[0025] Example 1

[0026] The high-stiffness composite packaging material comprises, from bottom to top, a 20μm thick PP nonwoven fabric layer, a 10μm thick connecting layer, and a 25μm thick printed film layer; the connecting layer consists of PP particles and PE particles in a mass ratio of 4:1; the printed film is a BOPP film.

[0027] The PP nonwoven fabric layer comprises the following components in parts by weight: 100 parts polypropylene, 1 part silica, 0.4 parts sebacic acid diphenyl dihydrazide, 0.6 parts zinc octanoate, 0.5 parts antioxidant 168, and 0.1 parts polyethylene wax;

[0028] The production process of high-stiffness composite packaging materials includes the following steps:

[0029] S1. The components of the PP nonwoven fabric layer are mixed and then melt-blown and pressed into shape to obtain the PP nonwoven fabric.

[0030] S2. After mixing the components of the connecting layer, the mixture is cast between the PP nonwoven fabric and the BOPP film to form a high-stiffness composite packaging material.

[0031] Example 2

[0032] The high-stiffness composite packaging material comprises, from bottom to top, a 25μm thick PP nonwoven fabric layer, a 12μm thick connecting layer, and a 28μm thick printed film layer; the connecting layer consists of PP granules and PE granules in a mass ratio of 4.5:1; the printed film is a BOPP film.

[0033] The PP nonwoven fabric layer comprises the following components in parts by weight: 100 parts polypropylene, 1.5 parts silica, 0.6 parts sebacic acid diphenyl dihydrazide, 0.9 parts zinc octanoate, 0.4 parts antioxidant BHT, 0.4 parts antioxidant 168, 0.1 parts polypropylene wax, and 0.1 parts polyethylene wax.

[0034] The production process of high-stiffness composite packaging materials includes the following steps:

[0035] S1. The components of the PP nonwoven fabric layer are mixed and then melt-blown and pressed into shape to obtain the PP nonwoven fabric.

[0036] S2. After mixing the components of the connecting layer, the mixture is cast between the PP nonwoven fabric and the BOPP film to form a high-stiffness composite packaging material.

[0037] Example 3

[0038] The high-stiffness composite packaging material comprises, from bottom to top, a 20μm thick PP nonwoven fabric layer, a 10μm thick connecting layer, and a 30μm thick printed film layer; the connecting layer consists of PP particles and PE particles in a mass ratio of 5:1; the printed film is a BOPP film.

[0039] The PP nonwoven fabric layer comprises the following components in parts by weight: 100 parts polypropylene, 2.5 parts silica, 1 part diphenyl dihydrazide sebacate, 1.5 parts zinc octanoate, 1 part antioxidant BHT, and 0.3 parts polypropylene wax.

[0040] The production process of high-stiffness composite packaging materials includes the following steps:

[0041] S1. The components of the PP nonwoven fabric layer are mixed and then melt-blown and pressed into shape to obtain the PP nonwoven fabric.

[0042] S2. After mixing the components of the connecting layer, the mixture is cast between the PP nonwoven fabric and the BOPP film to form a high-stiffness composite packaging material with a total thickness.

[0043] Example 4

[0044] The difference between this embodiment and Embodiment 3 is only that the PP nonwoven fabric layer includes the following components in parts by weight: 100 parts polypropylene, 4 parts silica, 0.5 parts sebacic acid diphenyl dihydrazide, 0.5 parts zinc octanoate, 1 part antioxidant BHT, and 0.3 parts polypropylene wax.

[0045] Example 5

[0046] The difference between this embodiment and Embodiment 3 is only that the PP nonwoven fabric layer includes the following components in parts by weight: 100 parts polypropylene, 3.5 parts silica, 1 part sebacate diphenyl dihydrazide, 0.5 parts zinc octanoate, 1 part antioxidant BHT, and 0.3 parts polypropylene wax.

[0047] Example 6

[0048] The difference between this embodiment and Embodiment 3 is only that the PP nonwoven fabric layer includes the following components in parts by weight: 100 parts polypropylene, 2.5 parts silica, 0.5 parts sebacic acid diphenyl dihydrazide, 2 parts zinc octanoate, 1 part antioxidant BHT, and 0.3 parts polypropylene wax.

[0049] Example 7

[0050] The only difference between this embodiment and Embodiment 6 is that the silica is n-heptanoic acid modified silica. The preparation method includes the following steps: dissolving n-heptanoic acid in ethanol and mixing it with silica, drying it to obtain n-heptanoic acid modified silica, wherein the mass ratio of n-heptanoic acid to silica is 1:14.

[0051] Example 8

[0052] The only difference between this embodiment and Embodiment 6 is that the silica is n-heptanoic acid modified silica. The preparation method includes the following steps: dissolving n-heptanoic acid in diethyl ether and mixing it with silica, drying it to obtain n-heptanoic acid modified silica, wherein the mass ratio of n-heptanoic acid to silica is 1:21.

[0053] Example 9

[0054] The only difference between this embodiment and Embodiment 8 is that the mass ratio of heptanoic acid to silicon dioxide is 1:15.

[0055] Example 10

[0056] The only difference between this embodiment and Embodiment 8 is that the mass ratio of heptanoic acid to silicon dioxide is 1:20.

[0057] Comparative Example 1

[0058] The only difference between this comparative example and Example 3 is that the PP nonwoven fabric layer includes the following components in parts by weight: 100 parts polypropylene, 5 parts silica, 1 part antioxidant BHT, and 0.3 parts polypropylene wax.

[0059] Comparative Example 2

[0060] The only difference between this comparative example and Example 3 is that the PP nonwoven fabric layer includes the following components in parts by weight: 100 parts polypropylene, 5 parts sebacic acid diphenyl dihydrazide, 1 part antioxidant BHT, and 0.3 parts polypropylene wax.

[0061] Comparative Example 3

[0062] The only difference between this comparative example and Example 3 is that the PP nonwoven fabric layer includes the following components in parts by weight: 100 parts polypropylene, 5 parts zinc octanoate, 1 part antioxidant BHT, and 0.3 parts polypropylene wax.

[0063] Comparative Example 4

[0064] The only difference between this comparative example and Example 3 is that the PP nonwoven fabric layer includes the following components in parts by weight: 100 parts polypropylene, 3.6 parts silica, 1.4 parts sebacic acid diphenyl dihydrazide, 1 part antioxidant BHT, and 0.3 parts polypropylene wax.

[0065] Comparative Example 5

[0066] The only difference between this comparative example and Example 3 is that the PP nonwoven fabric layer includes the following components in parts by weight: 100 parts polypropylene, 3.1 parts silica, 1.9 parts zinc octanoate, 1 part antioxidant BHT, and 0.3 parts polypropylene wax.

[0067] Comparative Example 6

[0068] The only difference between this comparative example and Example 3 is that the PP nonwoven fabric layer includes the following components in parts by weight: 100 parts polypropylene, 2 parts sebacic acid diphenyl dihydrazide, 3 parts zinc octanoate, 1 part antioxidant BHT, and 0.3 parts polypropylene wax.

[0069] Tensile strength (transverse) and elongation at break (transverse) of the packaging materials prepared in Examples 1-10 and Comparative Examples 1-6 were tested according to standard GB / T 1040.3-2006 "Determination of tensile properties of plastics - Part 3: Test conditions for films and sheets". The test results are shown in the table below:

[0070]

[0071] By comparing the data of Examples 1-10 and Comparative Examples 1-6, it was found that the packaging materials prepared in Examples 1-10 had higher tensile strength and elongation at break compared with Comparative Examples 1-6. This indicates that by introducing nucleating agents such as silica, sebacic acid diphenyl dihydrazide, and zinc octanoate into the PP nonwoven fabric layer of the high-stiffness composite packaging material, the strength and toughness of the PP nonwoven fabric were improved, and the stiffness of the composite packaging material could be significantly improved.

[0072] Comparing the data from Examples 6-10, it was found that the packaging materials prepared in Examples 7-10 had higher tensile strength and elongation at break compared to Example 6. This indicates that by using heptanoic acid to modify silica, the stability of the silica nucleating agent was improved, while its dispersibility in the polypropylene matrix was also improved. Furthermore, by adding sebacic acid diphenyl dihydrazide and zinc octanoate to the PP nonwoven fabric, the stiffness of the composite packaging material can be further improved.

[0073] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-stiffness composite packaging material, characterized in that, From bottom to top, the layers consist of a PP nonwoven fabric layer, a bonding layer, and a printed film layer; the bonding layer comprises PP particles and PE particles; the printed film is a BOPP film. The PP nonwoven fabric layer comprises the following components in parts by weight: 100 parts polypropylene, 2-5 parts nucleating agent, 0.5-1 part antioxidant, and 0.1-0.3 parts lubricant; The nucleating agent comprises the following components: silicon dioxide, sebacic acid diphenyl dihydrazide, and zinc octanoate; The mass ratio of silicon dioxide, sebacic acid diphenyl dihydrazide, and zinc octanoate is 5:1:4 to 7:2:

1.

2. The high-stiffness composite packaging material according to claim 1, characterized in that, The silica is heptanoic acid-modified silica.

3. The high-stiffness composite packaging material according to claim 2, characterized in that, In the n-heptanoic acid modified silica, the mass ratio of n-heptanoic acid to silica is 1:15~20.

4. The high-stiffness composite packaging material according to claim 2, characterized in that, The preparation method of the n-heptanoic acid modified silica includes the following steps: dissolving n-heptanoic acid and mixing it with silica, drying it to obtain n-heptanoic acid modified silica.

5. The high-stiffness composite packaging material according to claim 4, characterized in that, The solvent used for dissolution is either ethanol or diethyl ether.

6. The high-stiffness composite packaging material according to claim 1, characterized in that, The antioxidant is one or more of phosphite antioxidants and phenolic antioxidants; the lubricant is one or two of polyethylene wax and polypropylene wax.

7. The high-stiffness composite packaging material according to claim 1, characterized in that, The thickness of the connecting layer is 10~12μm.

8. The high-stiffness composite packaging material according to claim 1, characterized in that, The thickness of the BOPP film is 25~30μm.

9. The production process of a high-stiffness composite packaging material according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1. The components of the PP nonwoven fabric layer are mixed and then melt-blown and pressed into shape to obtain the PP nonwoven fabric. S2. After mixing the components of the connecting layer, the mixture is cast between the PP nonwoven fabric and the BOPP film to form a high-stiffness composite packaging material.

Images