Antistatic flexible isolation bag and production process thereof

Abstract

This invention discloses an antistatic flexible isolation bag and its manufacturing process, relating to the field of packaging materials technology. The manufacturing process of the antistatic flexible isolation bag of this invention includes the following steps: S1: Sequentially combining a nylon layer, an aluminum foil layer, and an antistatic dissipation layer to obtain a composite layer; S2: Sealing the composite layer to form a receiving cavity with an opening, with the antistatic dissipation layer disposed inside the receiving cavity, thus obtaining the isolation bag; the antistatic dissipation layer is made of modified polyethylene, which is prepared by reacting modified carbon black, carboxylated polyethylene, caprolactam, and 6-aminohexanoic acid. The modified polyethylene prepared in this application, as a raw material for the antistatic dissipation layer, has the advantages of good and stable antistatic effect.

Description

Technical Field

[0001] This invention relates to the field of packaging materials technology, specifically to an antistatic flexible isolation bag and its manufacturing process. Background Technology

[0002] With the rapid development of electronic technologies such as large-scale integrated circuits, a large number of electrostatic discharge (ESD) sensitive devices and products, such as unipolar transistors / field-effect transistors, surface mount devices, and microwave devices, are used in industrial manufacturing processes. The ESD sensitivity voltage is decreasing, making electronic products increasingly susceptible to ESD damage. In practical ESD protection work, when ESD sensitive components and products are transported between ESD protection zones or outside of ESD suppression zones, the packaging material in direct contact with these sensitive devices or products should be an ESD dissipative material. Antistatic shielding bags have become an important antistatic packaging product in the electronics manufacturing industry. These bags are generally made of three layers of laminated materials. The inner layer is an ESD dissipative layer made of materials such as polyethylene. When subjected to friction, the surface charge can diffuse and leak quickly, protecting the internal sensitive devices from charges or induced energy through the inner layer material to achieve equipotential balance. The middle layer is a shielding layer, mainly made of aluminum film, providing metallic shielding. The outer layer is a protective layer, mainly made of materials such as nylon, which reinforces the bag's wear resistance and durability.

[0003] Polyethylene (PE) is widely used in various fields due to its abundant and inexpensive raw material resources and stable and reliable production process. However, PE has a nonpolar molecular structure, consisting of covalently bonded molecular chains. While it cannot ionize, it can also transfer free electrons. Once charged due to the gain or loss of electrons caused by friction, it is difficult to eliminate. The static electricity generated by PE materials poses many hazards to packaging materials. Generally, antistatic agents and other appropriate additives are added to reduce the electrostatic potential of PE. Antistatic agents mainly include carbon black, carbon fiber, metal powder, and metal oxides. However, permanent antistatic additives, such as conductive carbon black, can lead to a decrease in mechanical properties, and the migration of antistatic additives under different humidity conditions can result in non-permanent conductivity. Summary of the Invention

[0004] The purpose of this invention is to provide an antistatic flexible isolation bag and its manufacturing process, thereby solving the following technical problems:

[0005] Existing antistatic additives, such as conductive carbon black, added to polyethylene can lead to a decrease in the material's mechanical properties and a darkening effect. Furthermore, under different humidity conditions, the migration of antistatic additives can result in non-permanent conductivity.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A manufacturing process for an antistatic flexible isolation bag includes the following steps:

[0008] S1: The nylon layer, aluminum foil layer and static dissipation layer are sequentially combined to obtain the composite layer;

[0009] S2: The composite layer is sealed to form a receiving cavity with a receiving opening, and the electrostatic dissipation layer is placed inside the receiving cavity to obtain an isolation bag;

[0010] The electrostatic dissipation layer is made of modified polyethylene. The preparation method of the modified polyethylene includes the following steps: In a nitrogen atmosphere, modified carbon black, carboxylated polyethylene and caprolactam are added to a reaction vessel and dispersed evenly. The temperature is controlled at 90-110℃. 6-aminohexanoic acid is added and the temperature is raised to 240-250℃. The mixture is kept at this temperature for 6-12 hours under mechanical stirring. Water is added for filtration and the precipitate is taken. The precipitate is washed with water to obtain modified polyethylene.

[0011] As a further embodiment of the present invention: the mass ratio of modified carbon black: modified polyethylene: caprolactam: 6-aminohexanoic acid is 5-10: 20-50: 10-20: 0.5-1.5.

[0012] As a further embodiment of the present invention, the preparation method of carboxylated polyethylene includes the following steps: adding deionized water and xylene to a reaction vessel, adding polyethylene, maleic anhydride and benzoyl peroxide, ultrasonically dispersing for 1-3 hours, controlling the temperature at 80-90℃, keeping warm for 6-9 hours, extracting with acetone and drying to obtain carboxylated polyethylene.

[0013] As a further aspect of the present invention: the polyethylene is low-density polyethylene.

[0014] As a further aspect of the present invention, the low-density polyethylene has an average molecular weight of 2000-3000.

[0015] As a further embodiment of the present invention: the mass ratio of deionized water, xylene, polyethylene, maleic anhydride, and benzoyl peroxide is 100-300:20-40:100:15-30:0.5-1.5.

[0016] As a further aspect of the present invention, the method for preparing modified carbon black includes the following steps:

[0017] A1: Add ethylenediamine and sodium nitrite to reaction flask A, add carbon black, disperse evenly, control the temperature at 50-60℃, keep warm for 3-6 hours, add concentrated sulfuric acid, keep warm for 0.5-1 hours, filter, wash with water, and dry to obtain component one;

[0018] A2: Add component one, phthalic anhydride, and tetrahydrofuran to reaction flask B, control the temperature at 35-45℃, keep warm for 3-6 hours, filter, wash with water, and dry to obtain modified carbon black.

[0019] As a further embodiment of the present invention: the concentrated sulfuric acid in A1 is a 95-98 wt% sulfuric acid solution, and the addition ratio of ethylenediamine, sodium nitrite, carbon black and concentrated sulfuric acid is 10-20 mL: 8-15 g: 5 g: 10-15 mL.

[0020] As a further aspect of the present invention: the mass ratio of component one, phthalic anhydride, and tetrahydrofuran in A2 is 1:0.5-2:30-100.

[0021] As a further aspect of the present invention: the aluminum foil layer thickness is 0.1-10μm; the nylon is nylon 6 or nylon 66, and the nylon layer thickness is 5-15μm; the electrostatic dissipation layer thickness is 4-12μm.

[0022] As a further embodiment of the present invention, the specific combination is as follows: hot plate temperature 150-170℃, pressure 1-5MPa, hot pressing for 1-5min.

[0023] An antistatic flexible isolation bag is manufactured using any one of the above-mentioned production processes.

[0024] The beneficial effects of this invention are:

[0025] (1) In this application, low-density polyethylene is modified with maleic anhydride to obtain carboxylated polyethylene; and carbon black surface is modified with ethylenediamine to obtain carbon black with a large number of amino groups grafted onto its surface as component one; modified carbon black is obtained by reacting the amino groups on the surface of carbon black with phthalic anhydride. In this application, modified carbon black and carboxylated polyethylene are used as raw materials, and modified polyethylene is obtained by crosslinking with caprolactam and 6-aminohexanoic acid. The modified polyethylene prepared in this application has excellent electrical conductivity and antistatic properties with the incorporation of modified carbon black. Furthermore, the crosslinking of modified carbon black and carboxylated polyethylene by caprolactam and 6-aminohexanoic acid gives carbon black higher stability in polyethylene, effectively avoiding the situation where the conductive material migrates under different humidity conditions, resulting in unstable conductivity. This application utilizes the crosslinking effect produced by caprolactam and 6-aminohexanoic acid to generate polar structural unit amide groups between polyethylene and carbon black. The hydrogen on the group combines with the oxygen on the carbonyl group of another molecule to form a strong hydrogen bond, which enhances the molecular forces between molecular chains, improves the mechanical strength and impact resistance of polyethylene material, and endows the material with high mechanical strength and melting point.

[0026] (2) In the process of modifying low-density polyethylene as a base material, polar groups are grafted onto polyethylene molecules to improve the hydrophilicity of the material and its ability to adsorb other particles, significantly enhance the interaction force between the resin matrix and conductive particles, improve the resistance stability of carboxylated polyethylene, and increase the resistance ratio of modified polyethylene.

[0027] (3) The electrostatic dissipation layer prepared by the modified polyethylene prepared in this application is heat-sealed with aluminum foil. The polar groups of the modified polyethylene itself give more functional groups that interact between the electrostatic dissipation layer and the aluminum foil, thereby improving the peel strength between the composite layers. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1

[0030] The preparation method of carboxylated polyethylene includes the following steps:

[0031] Add 100 mL of deionized water and 20 g of xylene to a reaction vessel, then add 100 g of polyethylene (Mr=2000), 15 g of maleic anhydride, and 0.5 g of benzoyl peroxide. Disperse the mixture ultrasonically for 1 h, control the temperature at 85 °C, and keep it at that temperature for 6 h. Extract with acetone and dry to obtain carboxylated polyethylene.

[0032] Example 2

[0033] The preparation method of modified carbon black includes the following steps:

[0034] A1: Add 100 mL of ethylenediamine and 80 g of sodium nitrite to reaction flask A, add 50 g of carbon black, disperse evenly, control the temperature at 50℃, keep warm for 3 h, add 100 mL of 98 wt% sulfuric acid solution, keep warm for 0.5 h, filter, wash with water, and dry to obtain component one;

[0035] A2: Add 50g of component one, 25g of phthalic anhydride, and 1500g of tetrahydrofuran to reaction flask B, control the temperature at 35℃, keep warm for 3h, filter, wash with water, and dry to obtain modified carbon black.

[0036] Example 3

[0037] The preparation method of modified carbon black includes the following steps:

[0038] A1: Add 200mL of ethylenediamine and 150g of sodium nitrite to reaction flask A, add 50g of carbon black, disperse evenly, control the temperature at 60℃, keep warm for 6h, add 150mL of 98wt% sulfuric acid solution, keep warm for 1h, filter, wash with water, and dry to obtain component one;

[0039] A2: Add 50g of component one, 100g of phthalic anhydride, and 5000g of tetrahydrofuran to reaction flask B, control the temperature at 45℃, keep warm for 6 hours, filter, wash with water, and dry to obtain modified carbon black.

[0040] Example 4

[0041] The preparation method of modified polyethylene includes the following steps:

[0042] In a nitrogen atmosphere, 20g of modified carbon black prepared in Example 2, 100g of carboxylated polyethylene prepared in Example 1, and 40g of caprolactam were added to a reaction vessel and dispersed evenly. The temperature was controlled at 100℃, and 3g of 6-aminohexanoic acid was added. The temperature was raised to 240℃ and kept at that temperature for 9 hours under mechanical stirring. Water was added for filtration, and the precipitate was collected. The precipitate was washed with water to obtain modified polyethylene.

[0043] Example 5

[0044] The preparation method of modified polyethylene includes the following steps:

[0045] In a nitrogen atmosphere, 30g of modified carbon black prepared in Example 2, 100g of carboxylated polyethylene prepared in Example 1, and 40g of caprolactam were added to a reaction vessel and dispersed evenly. The temperature was controlled at 100℃, and 3g of 6-aminohexanoic acid was added. The temperature was raised to 240℃ and kept at that temperature for 9 hours under mechanical stirring. Water was added for filtration, and the precipitate was collected. The precipitate was washed with water to obtain modified polyethylene.

[0046] Example 6

[0047] The preparation method of modified polyethylene includes the following steps:

[0048] In a nitrogen atmosphere, 40g of the modified carbon black prepared in Example 2, 100g of the carboxylated polyethylene prepared in Example 1, and 40g of caprolactam were added to a reaction vessel and dispersed evenly. The temperature was controlled at 100℃, and 3g of 6-aminohexanoic acid was added. The temperature was raised to 240℃ and kept at that temperature for 9 hours under mechanical stirring. Water was added for filtration, and the precipitate was collected. The precipitate was washed with water to obtain the modified polyethylene.

[0049] Example 7

[0050] The preparation method of modified polyethylene includes the following steps:

[0051] In a nitrogen atmosphere, 30g of modified carbon black prepared in Example 3, 100g of carboxylated polyethylene prepared in Example 1, and 40g of caprolactam were added to a reaction vessel and dispersed evenly. The temperature was controlled at 100℃, and 3g of 6-aminohexanoic acid was added. The temperature was raised to 240℃ and kept at that temperature for 9 hours under mechanical stirring. Water was added for filtration, and the precipitate was collected. The precipitate was washed with water to obtain modified polyethylene.

[0052] Example 8

[0053] A manufacturing process for an antistatic flexible isolation bag includes the following steps:

[0054] S1: A 5μm thick electrostatic dissipation layer was made from the modified polyethylene prepared in Example 4, and a 5μm thick nylon layer was made from nylon 6.

[0055] S2: After stacking the nylon layer, the 1μm aluminum foil layer and the static dissipation layer in sequence, heat-sealing them under the conditions of hot plate temperature of 150℃, pressure of 2MPa and hot pressing for 2min, a composite layer is obtained.

[0056] S3: The composite layer is sealed to form a receiving cavity with a receiving opening, and the electrostatic dissipation layer is placed inside the receiving cavity to obtain an isolation bag.

[0057] Example 9

[0058] A manufacturing process for an antistatic flexible isolation bag includes the following steps:

[0059] S1: A 5μm thick electrostatic dissipation layer was made from the modified polyethylene prepared in Example 5, and a 5μm thick nylon layer was made from nylon 6.

[0060] S2: After stacking the nylon layer, the 1μm aluminum foil layer and the static dissipation layer in sequence, heat-sealing them under the conditions of hot plate temperature of 150℃, pressure of 2MPa and hot pressing for 2min, a composite layer is obtained.

[0061] S3: The composite layer is sealed to form a receiving cavity with a receiving opening, and the electrostatic dissipation layer is placed inside the receiving cavity to obtain an isolation bag.

[0062] Example 10

[0063] A manufacturing process for an antistatic flexible isolation bag includes the following steps:

[0064] S1: A 5μm thick electrostatic dissipation layer was made from the modified polyethylene prepared in Example 6, and a 5μm thick nylon layer was made from nylon 6.

[0065] S2: After stacking the nylon layer, the 1μm aluminum foil layer and the static dissipation layer in sequence, heat-sealing them under the conditions of hot plate temperature of 150℃, pressure of 2MPa and hot pressing for 2min, a composite layer is obtained.

[0066] S3: The composite layer is sealed to form a receiving cavity with a receiving opening, and the electrostatic dissipation layer is placed inside the receiving cavity to obtain an isolation bag.

[0067] Example 11

[0068] A manufacturing process for an antistatic flexible isolation bag includes the following steps:

[0069] S1: A 5μm thick electrostatic dissipation layer was made from the modified polyethylene prepared in Example 7, and a 5μm thick nylon layer was made from nylon 6.

[0070] S2: After stacking the nylon layer, the 1μm aluminum foil layer and the static dissipation layer in sequence, heat-sealing them under the conditions of hot plate temperature of 150℃, pressure of 2MPa and hot pressing for 2min, a composite layer is obtained.

[0071] S3: The composite layer is sealed to form a receiving cavity with a receiving opening, and the electrostatic dissipation layer is placed inside the receiving cavity to obtain an isolation bag.

[0072] Comparative Example 1

[0073] The preparation method of modified carbon black includes the following steps:

[0074] Add 100 mL of ethylenediamine and 80 g of sodium nitrite to reaction flask A, add 50 g of carbon black, disperse evenly, control the temperature at 50℃, keep warm for 3 h, add 100 mL of 98 wt% sulfuric acid solution, keep warm for 0.5 h, filter, wash with water, and dry to obtain modified carbon black.

[0075] Comparative Example 2

[0076] Compared with Example 4, Comparative Example 2 only replaced the modified carbon black prepared in Example 2 with the modified carbon black prepared in Comparative Example 1 in an equal amount. The remaining components and steps were completely the same as in Example 4.

[0077] Comparative Example 3

[0078] Compared with Example 4, Comparative Example 3 only replaced the carboxylated polyethylene prepared in Example 1 with polyethylene in an equal amount, while the remaining components and steps were completely the same as in Example 4.

[0079] Comparative Example 4

[0080] The preparation method of modified polyethylene includes the following steps:

[0081] In a nitrogen atmosphere, 20g of the modified carbon black prepared in Example 2 and 100g of the carboxylated polyethylene prepared in Example 1 were added to a reaction vessel, dispersed evenly, heated to 240°C, and kept at that temperature for 9 hours under mechanical stirring. Water was added for filtration, the precipitate was collected, and the precipitate was washed with water to obtain the modified polyethylene.

[0082] Comparative Example 5

[0083] Compared with Example 8, Comparative Example 5 only replaced the modified polyethylene prepared in Example 4 with the modified polyethylene prepared in Comparative Example 2 in an equal amount. The remaining components and steps were completely the same as in Example 8.

[0084] Comparative Example 6

[0085] Compared with Example 8, Comparative Example 6 only replaced the modified polyethylene prepared in Example 4 with the modified polyethylene prepared in Comparative Example 3 in an equal amount. The remaining components and steps were completely the same as in Example 8.

[0086] Comparative Example 7

[0087] Compared with Example 8, Comparative Example 7 only replaced the modified polyethylene prepared in Example 4 with an equal amount of the modified polyethylene prepared in Comparative Example 4 in Example 8, while the remaining components and steps were completely the same as in Example 8.

[0088] Performance testing

[0089] (1) The mechanical properties of the modified polyethylene prepared in Examples 4-7 and Comparative Examples 2-4 were tested;

[0090] a: Tensile properties: Tested according to GB / T 1040-1992 "Test Method for Tensile Properties of Plastics", with a tensile rate of 50 mm / min. The tensile strength is calculated using the following formula:

[0091] σ = P / (bd)

[0092] In the formula, σ is the tensile strength (MPa); P is the maximum load (N); b is the specimen width (mm); and d is the specimen thickness (mm).

[0093] b: Impact performance: Tested according to GB / T 1843-2008 "Determination of impact strength of plastic cantilever beams", the impact strength is calculated as follows:

[0094] a = [A / (bd)] × 10 3

[0095] Where: α - impact strength, kJ / m 2 A - Impact energy absorbed by the sample, J; b - Remaining width of the sample, mm; d - Sample thickness, mm;

[0096] The modified polyethylene prepared in this application has excellent mechanical properties. Compared with the direct addition of carbon black, this application utilizes caprolactam and 6-aminohexanoic acid to crosslink polyethylene and carbon black, which greatly improves the mechanical strength and impact resistance of the polyethylene material, and endows the material with higher mechanical strength and melting point.

[0097] (2) Peel strength: The aluminum foil layer and static dissipation layer of Examples 8, 9, 10, 11, Comparative Example 5, Comparative Example 6, and Comparative Example 7 were stacked and hot-pressed to obtain Examples 8-1, 9-1, 10-1, 11-1, Comparative Example 5-1, Comparative Example 6-1, and Comparative Example 7-1. They were tested according to GB / T 2791-1995 "Adhesives T Peel Strength Test Method Flexible Materials to Flexible Materials", with a separation speed of 100 mm / min and a sample peel length of 125 mm.

[0098] The modified polyethylene prepared in this application is laminated with aluminum foil by hot pressing and has high peel strength.

[0099] (3) Conductivity: According to GB / T 1410-2006 "Test Methods for Volume Resistivity and Surface Resistivity of Solid Insulating Materials", a ZC-36 high resistance meter produced by Shanghai Anbiao Electronic Co., Ltd. was used. The test voltage was 1000V, the sample diameter was 100mm, and the thickness was 4mm. The test environment was: temperature 25±2℃, relative humidity 65±5% (treated under these conditions for 16 hours).

[0100] Surface resistivity R = meter reading × 10⁶ × magnification factor × test voltage factor

[0101] The volume resistivity ρv is calculated using the following formula: ρv = (RvS) / L

[0102] In the formula, ρv is the volume resistivity; Rv is the measured resistance value of the sample; and S is the effective area on the test plate (mm²). 2 L - Sample thickness, mm; Test results are shown in Table 1;

[0103] (4) Resistance stability: The modified polyethylene of Examples 4-7 and Comparative Examples 2-4 were subjected to five full-range thermal cycles (20-150℃) at a heating rate of 5℃ / min. The resistance value was tested using a KEITHLEY 2000 multimeter. The test results are shown in Table 1.

[0104] Table 1: Statistical Table of Resistance Performance Test Data of Modified Polyethylene in Examples 4-7 and Comparative Examples 2-4

[0105]

[0106] As shown in Table 1, the modified polyethylene prepared in this application has excellent electrical conductivity and antistatic properties, as well as good thermal cycling resistance stability.

[0107] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A manufacturing process for an antistatic flexible isolation bag, characterized in that, Includes the following steps: S1: The nylon layer, aluminum foil layer and static dissipation layer are sequentially combined to obtain the composite layer; S2: The composite layer is sealed to form a receiving cavity with a receiving opening, and the electrostatic dissipation layer is placed inside the receiving cavity to obtain an isolation bag; The electrostatic dissipation layer is made of modified polyethylene. The preparation method of the modified polyethylene includes the following steps: In a nitrogen atmosphere, modified carbon black, carboxylated polyethylene and caprolactam are added to a reaction vessel and dispersed evenly. The temperature is controlled at 90-110℃. 6-aminohexanoic acid is added and the temperature is raised to 240-250℃. The mixture is kept at this temperature for 6-12 hours under mechanical stirring. Water is added for filtration and the precipitate is taken. The precipitate is washed with water to obtain modified polyethylene. The preparation method of modified carbon black includes the following steps: A1: Add ethylenediamine and sodium nitrite to reaction flask A, add carbon black, disperse evenly, control the temperature at 50-60℃, keep warm for 3-6 hours, add concentrated sulfuric acid, keep warm for 0.5-1 hours, filter, wash with water, and dry to obtain component one; A2: Add component one, phthalic anhydride, and tetrahydrofuran to reaction flask B, control the temperature at 35-45℃, keep warm for 3-6 hours, filter, wash with water, and dry to obtain modified carbon black.

2. The manufacturing process of an antistatic flexible isolation bag according to claim 1, characterized in that, The mass ratio of modified carbon black, carboxylated polyethylene, caprolactam, and 6-aminohexanoic acid is 5-10:20-50:10-20:0.5-1.

5.

3. The manufacturing process of an antistatic flexible isolation bag according to claim 1, characterized in that, The preparation method of carboxylated polyethylene includes the following steps: adding deionized water and xylene into a reaction vessel, adding polyethylene, maleic anhydride and benzoyl peroxide, ultrasonically dispersing for 1-3 hours, controlling the temperature at 80-90℃, keeping warm for 6-9 hours, extracting with acetone and drying to obtain carboxylated polyethylene.

4. The manufacturing process of an antistatic flexible isolation bag according to claim 3, characterized in that, The mass ratio of deionized water, xylene, polyethylene, maleic anhydride, and benzoyl peroxide is 100-300:20-40:100:15-30:0.5-1.

5.

5. The manufacturing process of an antistatic flexible isolation bag according to claim 1, characterized in that, In A1, the concentrated sulfuric acid is a 95-98 wt% sulfuric acid solution, and the addition ratio of ethylenediamine, sodium nitrite, carbon black, and concentrated sulfuric acid is 10-20 mL: 8-15 g: 5 g: 10-15 mL.

6. The manufacturing process of an antistatic flexible isolation bag according to claim 1, characterized in that, In component A2, the mass ratio of component 1, phthalic anhydride, and tetrahydrofuran is 1:0.5-2:30-100.

7. The manufacturing process of an antistatic flexible isolation bag according to claim 1, characterized in that, The aluminum foil layer has a thickness of 0.1-10μm; the nylon is nylon 6 or nylon 66, and the nylon layer has a thickness of 5-15μm; the electrostatic dissipation layer has a thickness of 4-12μm.

8. The manufacturing process of an antistatic flexible isolation bag according to claim 1, characterized in that, The specific combination is as follows: hot plate temperature 150-170℃, pressure 1-5MPa, hot pressing for 1-5min.

9. An antistatic flexible isolation bag, characterized in that, Made by the manufacturing process described in any one of claims 1-8.

Images