High-strength packaging bag with effects of heat preservation and watertightness, and preparation process thereof

Abstract

A high-strength packaging bag with effects of heat preservation and watertightness is made of a composite paper. The composite paper includes an outer waterproof layer, an outer paper layer, a first adhesive layer, a heat-insulation and cushioning layer, a second adhesive layer, an inner paper layer and an inner waterproof layer arranged in sequence; and the first adhesive layer and the second adhesive layer are both elastic adhesive layers.

Claims

1. A packaging bag, wherein the packaging bag is made of a composite paper, wherein the composite paper comprises an outer waterproof layer, an outer paper layer, a heat-insulation and cushioning layer, an inner paper layer and an inner waterproof layer adhered to one another in sequence; the outer paper layer and the heat-insulation and cushioning layer are adhered together by a first adhesive layer; the inner paper layer and the heat-insulation and cushioning layer are adhered together by a second adhesive layer; and the first adhesive layer and the second adhesive layer are both elastic adhesive layers; wherein the first adhesive layer and the second adhesive layer are formed by curing an adhesive prepared from the following materials in parts by weight: 40-60 parts of polyurethane emulsion, 12-22 parts of tackifier, 4-8 parts of impregnating agent, 0.5-2 parts of alkyl silane coupling agent, and 20-30 parts of water; wherein the tackifier is prepared by the following steps: A1, adding 10-18 parts of starch to 80-120 parts of the water, in parts by weight, adding dropwise 0.3-0.8 parts of 1-2 mol/L hydrochloric acid aqueous solution, in parts by weight, heating to 65-85 C., and stirring for 30-60 min to obtain a starch hydrolysate; and A2, adding 0.2-0.5 parts of diethylene glycol, 0.1-0.3 parts of acrylate copolymer and 1-3 parts of magnesium aluminum silicate, in parts by weight, to the starch hydrolysate, and stirring uniformly to obtain the tackifier.

2. The packaging bag according to claim 1, wherein a first cushioning structure is provided at a side of the outer waterproof layer adjacent to the heat-insulation and cushioning layer; a second cushioning structure is provided at a side of the inner waterproof layer adjacent to the heat-insulation and cushioning layer; the first cushioning structure is identical to the second cushioning structure; and the first cushioning structure and the second cushioning structure are symmetrically arranged.

3. The packaging bag according to claim 2, wherein the first cushioning structure comprises a plurality of protrusions; each protrusion of the plurality of protrusions having a height in a thickness direction of the composite paper extending from the outer waterproof layer to the first adhesive layer; and the plurality of protrusions gradually increase in height from a central region to a peripheral edge region of the outer paper layer.

4. The packaging bag according to claim 3, wherein a distribution density of each of the plurality of protrusions is gradually decreased from the central region to the peripheral edge region of the outer paper layer.

5. The packaging bag according to claim 1, wherein the heat-insulation and cushioning layer is any one selected from the group consisting of aerogel cotton, organosilicon cotton and pearl cotton.

6. The packaging bag according to claim 1, wherein the impregnating agent comprises oleylamine polyoxyethylene ether and polyvinyl alcohol in a weight ratio of 1:(0.2-0.6).

7. The packaging bag according to claim 1, wherein the adhesive is prepared by the following steps: B1, adding the impregnating agent into the water, and stirring uniformly to obtain a mixed solution; and B2, adding the polyurethane emulsion, the tackifier and the long-chain alkyl silane coupling agent to the mixed solution, and stirring uniformly to prepare the adhesive.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram showing the interlaminar structure of a composite paper of a high-strength packaging bag with effects of heat preservation and watertightness according to Example 1 of the present application;

(2) FIG. 2 is a schematic view showing the interlaminar structure of a composite paper of a high-strength packaging bag with effects of heat preservation and watertightness according to Example 4 of the present application;

(3) FIG. 3 is a schematic view showing the interlaminar structure of composite paper for a high-strength packaging bag with effects of heat preservation and watertightness according to Example 5 of the present application.

(4) Reference numerals: 1, outer waterproof layer; 2, outer paper layer, 21, first cushioning structure; 3, first adhesive layer; 4, heat-insulation and cushioning layer; 5, second adhesive layer; 6, inner paper layer; 61, second cushioning structure; 7, inner waterproof layer.

DETAILED DESCRIPTION

(5) The present application is described in further detail below with reference to FIGS. 1-3 and Examples.

(6) The following are the sources and specifications of some raw materials of the present application. The raw materials in the preparation examples and examples of the present application may be obtained commercially. The raw materials used in the present application include but are not limited to those of the specific models and manufacturers disclosed below. The raw materials with the same specification parameters and properties may be used: 1, starch: corn starch; industrial grade; content, 99%; 2, acrylate copolymer: carbomer U21; available from Lubrizol; 3, magnesium aluminum silicate: 325 meshes; content, 99%; pH=6.3; whiteness, 90%; 4, kaolin: calcined kaolin; 325 meshes; density, 2.54-2.60 g/cm.sup.3; 5, polyurethane emulsion: available from Bayer; content, 40-50%; viscosity 700-1500 mPa.Math.s at 25 C.; pH=7-9; density, 1.04-1.09 g/cm.sup.3; 6, oleylamine polyoxyethylene ether: (Z)-2,2-(octadec-9-enylimino) bisethanol; 7, polyvinyl alcohol: molecular weight, 25,000-35,000 Daltons; content, 99%; pH=4.5-6.5.

Preparation Examples of Tackifiers

Preparation Example 1

(7) Preparation Example 1 discloses a tackifier prepared by the following steps.

(8) A1. 1 kg of starch was added to 8 kg of water. 0.03 kg of 1 mol/L hydrochloric acid aqueous solution was dropwise added, the temperature was increased to 65 C., while stirring for 30 minutes, to obtain a starch hydrolysate.

(9) A2. The tackifier was prepared by adding 0.02 kg of diethylene glycol, 0.01 kg of carbomer U21 and 0.1 kg of magnesium aluminum silicate to the starch hydrolysate and stirring for 20 min at a stirring rate of 300 r/min.

Preparation Examples 2-3

(10) Preparation Examples 2-3 differ from Preparation Example 1 in the amount of raw materials used and the preparation conditions. See Table 1 below for details.

(11) TABLE-US-00001 TABLE 1 Table of raw material amounts and preparation conditions of Preparation Examples 1-3 Preparation Examples Preparation Preparation Preparation Items Example 1 Example 2 Example 3 A1 steps, Starch Amount/kg 1 1.4 1.8 and starch Water Amount/kg 8 10 12 hydrolysate Hydrochloric Concentration/ 1 1.5 2 preparation acid aqueous mol/L solution Amount/kg 0.03 0.06 0.08 temperature/ C. 65 75 85 Stirring time/min 30 45 60 A2 steps, Diethylene Amount/kg 0.02 0.035 0.05 and glycol tackifier Carbomer Amount/kg 0.01 0.02 0.03 preparation U21 Magnesium Amount/kg 0.1 0.2 0.3 aluminum silicate Stirring time/min 20 30 40 Stirring rate/r/min 300 600 1000

(12) Preparative Comparative Example 1 differs from Preparation Example 1 in that diethylene glycol was replaced by polyethylene glycol 400 in equal amounts, and the others were the same as those in Preparation Example 1.

Preparative Comparative Example 2

(13) Preparation Comparative Example 2 differs from Preparation Example 1 in that magnesium aluminum silicate was replaced by kaolin in equal amounts, and the others were the same as those in Preparation Example 1.

Preparative Comparative Example 3

(14) Preparation Comparative Example 3 differs from Preparation Example 1 in that carbomer U21 was replaced by hydroxyethyl methylcellulose in equal amounts, and the others were the same as those in Preparation Example 1.

Preparative Comparative Example 4

(15) Preparation Comparative Example 4 differs from Preparation Example 1 in that the magnesium aluminum silicate was replaced by carbomer U21 in equal amounts, and the others were the same as those in Preparation Example 1.

Preparation Examples of Adhesives

Preparation Example 4

(16) Preparation Example 4 discloses an adhesive prepared by the following steps.

(17) B1. 0.4 kg of polyvinyl alcohol was added as a impregnating agent to 2 kg of water at a temperature of 60 C., while stirring uniformly at a stirring rate of 300 r/min for 20 min, to prepare a mixed solution.

(18) B2. 4 kg of polyurethane emulsion, 1.2 kg of hydroxyethyl methylcellulose as a tackifier and 0.05 kg of dodecyl trimethoxy silane as a silane coupling agent were added to the mixed solution, while stirring uniformly at a stirring rate of 300 r/min for 30 min, to prepare an adhesive.

Preparation Examples 5-6

(19) Preparation Examples 5-6 differ from Preparation Example 1 in the amount of raw materials used and the preparation conditions. See Table 2 below for details.

(20) TABLE-US-00002 TABLE 2 Table of raw material amounts and preparation conditions of Preparation Examples 4-6 Preparation Examples Preparation Preparation Preparation Items Example 4 Example 5 Example 6 B1, mixed Impregnating Kinds Polyvinyl Polyvinyl Polyvinyl solution agent alcohol alcohol alcohol preparation Amount/kg 0.4 0.6 0.8 Water Amount/kg 2 2.5 3 Stirring temperature/ C. 60 65 70 Stirring time/min 20 30 40 Stirring rate/r/min 300 600 900 B2, Polyurethane Amount/kg 4 5 6 adhesive emulsion preparation Tackifier Kinds Hydroxyethyl Hydroxyethyl Maltodextrin methylcellulose methylcellulose Amount/kg 1.2 1.8 2.2 Long-chain Dodecyl Dodecyl Dodecyl alkyl silane Kinds trimethoxy trimethoxy trimethoxy coupling silane silane silane agent Amount/kg 0.05 0.1 0.2 Stirring time/min 30 45 60 Stirring rate/r/min 500 1000 1500

Preparation Examples 7-13

(21) Preparation Examples 7-13 differ from Preparation Example 4 in that the source of the tackifier is different. See Table 3 below.

(22) TABLE-US-00003 TABLE 3 Table of Sources of Tackifiers for Preparation Examples 7-13 Preparation Examples Sources of tackifiers Preparation Example 7 Preparation Example 1 Preparation Example 8 Preparation Example 2 Preparation Example 9 Preparation Example 3 Preparation Example 10 Preparative Comparative Example 1 Preparation Example 11 Preparative Comparative Example 2 Preparation Example 12 Preparative Comparative Example 3 Preparation Example 13 Preparative Comparative Example 4
Preparation Example 14

(23) Preparation Example 14 differs from preparation example 7 in that the impregnating agent was different. The impregnating agent in Preparation Example 14 was composed of oleylamine polyoxyethylene ether and polyvinyl alcohol. The amount of oleylamine polyoxyethylene ether was 0.33 kg. The amount of polyvinyl alcohol was 0.07 kg, and the others were the same as those in Preparation Example 7.

(24) Preparation Example 15

(25) Preparation Example 15 differs from Preparation Example 7 in that the impregnating agent in Preparation Example 15 was composed of oleylamine polyoxyethylene ether and polyvinyl alcohol. The amount of oleylamine polyoxyethylene ether was 0.25 kg. The amount of polyvinyl alcohol was 0.15 kg, and the others were the same as those in Preparation Example 7.

Preparative Comparative Example 5

(26) Preparative Comparative Example 5 differs from Preparation Example 14 in that the long-chain alkyl silane coupling agent was replaced by the methyltriethoxysilane coupling agent in equal amounts, and the others were the same as those in Preparation Example 14.

EXAMPLES

Example 1

(27) Example 1 discloses a high-strength packaging bag with effects of heat preservation and watertightness, which was prepared by cutting and combining a composite paper. With reference to FIG. 1, the composite paper includes an outer waterproof layer, an outer paper layer, a heat-insulation and cushioning layer, an inner paper layer and an inner waterproof layer adhered in sequence. The outer paper layer and the heat-insulation and cushioning layer were adhered by a first adhesive layer. The inner paper layer and the heat-insulation and cushioning layer were adhered by a second adhesive layer. The outer waterproof layer and the inner waterproof layer were polyethylene (PE) waterproof layers. The outer paper layer and the inner paper layer were both kraft paper. The thickness of the kraft paper was 0.1-1 mm. The thickness of the kraft paper in this Example is 0.5 mm. The heat-insulation and cushioning layer was aerogel cotton, organosilicon cotton, pearl cotton, etc. The heat-insulation and cushioning layer in this Example was organosilicon cotton. The thickness of the heat-insulation and cushioning layer was 0.1-2 mm. The thickness of the heat-insulation and cushioning layer in this Example was 1 mm. Both the first adhesive layer and the second adhesive layer were adhesive layers having elasticity and were prepared by curing the adhesive.

(28) The high-strength packaging bag with effects of heat preservation and watertightness was prepared by the following steps.

(29) S1, a commercially available adhesive was coated on a side of the heat-insulation and cushioning layer, with the coating amount controlled to be 30 g/m.sup.2 to form a first adhesive layer. The first adhesive layer was adhered with an outer paper layer. The temperature was maintained at 40 C. for 20 min, and then drying was performed under the condition of 100 C.

(30) S2, a commercially available adhesive was coated a side of the heat-insulation and cushioning layer away from the outer paper layer, with the coating amount controlled to be 30 g/m.sup.2 to form a second adhesive layer. The second adhesive layer was adhered with the outer paper layer. The temperature was maintained at 40 C. for 20 min, and then drying was performed under the condition of 100 C.

(31) S3, the PE material was melted to form a PE waterproof agent for tape-casting and coating the inner paper layer to form an inner waterproof layer. The PE waterproof agent was coated on the outer paper layer to form an outer waterproof layer. The coating amount of the PE waterproof agent was controlled to be 10 g/m.sup.2, dried at a temperature of 20 C. for a drying time of 30 min to prepare a composite paper.

(32) S4, the composite paper was cut and combined to prepare a high-strength packaging bag with effects of heat preservation and watertightness.

(33) In particular, the commercially available adhesive was waterborne polyurethane adhesive from Depont Nanotechnology; viscosity, 100-450 cps at 25 C.; solid content, 40%; pH=7.0-8.5; PE material: low density polyethylene; available from Dow chemistry; model 4203; Aerogel cotton: thermal conductivity, 0.02 W/(m.Math.K); compressive strength, 18 MPa; density, 180-220 kg/m.sup.3; Organosilicon cotton: thermal conductivity, 0.02 W/(m.Math.K); density, 120-160 kg/m.sup.3; and Pearl cotton: EPE foamed cotton, thermal conductivity, 0.02 W/(m.Math.K); density, 28-35 kg/m.sup.3.

Examples 2-3

(34) Examples 2-3 differ from Example 1 in that the preparation process parameters were different and the sources of the adhesives were different. See Table 4 below for details.

(35) TABLE-US-00004 TABLE 4 Table of preparation process parameters and sources of adhesives in Examples 1-3 Examples Items Example 1 Example 2 Example 3 S1 step Source of Adhesive Com- Com- Com- mercially mercially mercially available available available Coating amount of 30 40 50 adhesive g/m.sup.2 Heat preservation 20 30 40 time/min Heat preservation 40 50 60 temperature/ C. Drying 100 110 120 temperature/ C. S2 step Source of Adhesive Com- Com- Com- mercially mercially mercially available available available Coating amount of 30 40 50 adhesive g/m.sup.2 Heat preservation 20 30 40 time/min Heat preservation 40 50 60 temperature/ C. Drying 100 110 120 temperature/ C. S2 step Coating amount of 10 15 20 PE waterproof agent g/m.sup.2 Drying 20 28 35 temperature/ C. Drying time/min 30 40 50

Example 4

(36) Example 4 differs from Example 1 in that, with reference to FIG. 2, the structure of the composite paper was different. A first cushioning structure was disposed at a side of the outer waterproof layer adjacent to the heat-insulation and cushioning layer, and a second cushioning structure was disposed at a side of the inner waterproof layer adjacent to the heat-insulation and cushioning layer. The structures of the first cushioning structure and the second cushioning structure were same. The first cushioning structure was composed of a plurality protrusions. The horizontal height of the protrusions gradually increased from a central region to a peripheral edge region of the outer paper layer. The first cushioning structure and the second cushioning structure were the same, the distribution density of the protrusions was the same, and the others were the same as those in Example 1.

Example 5

(37) Examples 5 differs from Examples 4 in that, with reference to FIG. 3, on the basis of Example 4, the distribution density of the protrusion gradually decreases from the central region to the peripheral edge region of the outer paper layer, the distribution density of the protrusion of the inner paper layer was the same as that of the outer paper layer, and the others were the same as those in Example 4.

Examples 6-18

(38) Examples 6-18 differ from Example 5 in that the sources of the adhesive were different. See Table 5 below for details.

(39) TABLE-US-00005 TABLE 5 Sources of adhesives in Examples 6-18 Examples Source of adhesive Example 6 Preparation Example 4 Example 7 Preparation Example 5 Example 8 Preparation Example 6 Example 9 Preparation Example 7 Example 10 Preparation Example 8 Example 11 Preparation Example 9 Example 12 Preparation Example 10 Example 13 Preparation Example 11 Example 14 Preparation Example 12 Example 15 Preparation Example 13 Example 16 Preparation Example 14 Example 17 Preparation Example 15 Example 18 Preparative Comparative Example 5
Performance Detection Test

(40) The high-strength packaging bag with effects of heat preservation and watertightness prepared in Examples 1-18 were subjected to performance tests as follows:

(41) (1) Folding Endurance Test

(42) The folding endurance of the high-strength packaging bag with effects of heat preservation and watertightness (unit: times) was determined according to the test method in GB/T 13024-2003. The results were recorded.

(43) (2) Bursting Strength Test

(44) The burst index of the high-strength packaging bag with effects of heat preservation and watertightness (unit: kpa.Math.m.sup.2/g) was determined according to the test method in GB/T 13024-2003. The results were recorded.

(45) (3) Peel Strength Test

(46) The peel strength of the high-strength packaging bag with effects of heat preservation and watertightness (unit: N/cm) was determined according to the test method in GB/T 34444-2017. The results were recorded.

(47) The following are performance test data for the high-strength packaging bag with effects of heat preservation and watertightness prepared in Examples 1-18. See Table 6 below for details.

(48) TABLE-US-00006 TABLE 6 Performance test data table for high-strength packaging bag with effects of heat preservation and watertightness in Examples 1-18 Items Folding Burst index/ Peel strength/ Examples endurance/time kPa .Math. m.sup.2/g N/cm Example 1 69 2.25 9.21 Example 2 70 2.3 9.44 Example 3 71 2.35 9.42 Example 4 72 2.45 10.1 Example 5 73 2.5 10.5 Example 6 75 2.65 11.07 Example 7 75 2.7 11.09 Example 8 76 2.7 11.12 Example 9 81 2.9 11.91 Example 10 82 2.95 11.96 Example 11 83 2.95 12 Example 12 79 2.8 11.61 Example 13 80 2.9 11.67 Example 14 80 2.85 11.74 Example 15 78 2.8 11.49 Example 16 84 3 12.26 Example 17 85 3 12.3 Example 18 82 2.9 11.93

(49) In combination with Examples 1-5 and Table 6, it can be seen that the first cushioning structure of the outer paper layer and the second cushioning structure of the inner paper layer cooperate with the heat-insulation and cushioning layer in the present application, which may improve the strength of the prepared packaging bag and cause the interlayer bonding more stable, and it is less prone to be wrinkled and deformed. The protrusions in Example 2 are evenly distributed, while the protrusions in Example 3 has a successively decreased distribution density from the central region to the peripheral edge region. It can be seen from the data that the peel strength in Example 2 is slightly greater than that in Example 3. Use of the protrusions with uniform distribution is possibly more conducive to adhering. However, the fold resistance and burst index in Example 2 are significantly greater than those in Example 3, indicating that the difference in the distribution density of the protrusion can improve the strength of the prepared packaging bag. In summary, the performance of the packaging bag in Example 3 is better.

(50) It can be seen in combination with Examples 1-5 and Examples 6-15 and in combination with Table 6 that the use of the tackifier of the present application may further improve the bonding stability of the prepared adhesive and improve the strength of the prepared packaging bag. However, in Examples 12-15, no starch, diethylene glycol, carbomer U21 and magnesium aluminum silicate is used for compounding, the strength of the prepared packaging bag is reduced and the folding resistance is also reduced, indicating that the starch, diethylene glycol, carbomer U21 and magnesium aluminum silicate can produce a good synergistic effect and the strength of the prepared packaging bag is better.

(51) It can be seen by combining with Examples 9-11 and Examples 16-17 and in combination with Table 6 that using the preferred ratio of oleylamine polyoxyethylene ether and polyvinyl alcohol of the present application for compounding may produce a better synergistic effect with the tackifier, further improving the interlayer bonding stability of the packaging bag and improving the strength of the prepared packaging bag.

(52) As can be seen in combination with Examples 16-17 and Example 18 and in combination with Table 6, the use of a long-chain alkyl silane coupling agent improves the strength of the prepared packaging bag.

(53) In summary, in the present application, a composite paper is formed by adhering an outer waterproof layer, an outer paper layer, a first adhesive layer, a heat-insulation and cushioning layer, a second adhesive layer, an inner paper layer and an inner waterproof layer. The packaging bag prepared from the composite paper has better thermal insulation property, waterproof property and strength. At the same time, the adhesive of the present application is used for curing to form a first adhesive layer and a second adhesive layer, which have better elasticity and bonding property, are not easy to be wrinkled and deformed when exposed to external pressure, and further improve the cushioning performance and strength of the obtained packaging bag.

(54) The specific embodiments are merely an explanation to the present application and is not a limitation to the present application. After reading this specification, a person skilled in the art may modify this embodiment without creative contribution as needed, but as long as it is within the scope of the claims of this application, it is protected by the patent law.