Moisture-proof corrugated paper and preparation method thereof

Abstract

The invention relates to the technical field of paper products, and proposes a moisture-proof corrugated paper and a preparation method thereof. The moisture-proof corrugated paper comprises, from top to bottom, an upper paper, a corrugated paper core and a lower paper, wherein the upper paper and the corrugated paper core are bonded by an adhesive, and the corrugated paper core and the lower paper are bonded by an adhesive, and the adhesives independently comprise the following components in parts by weight: 35-45 parts of corn starch, 10-30 parts of epoxy compound-modified corn starch, 1-2 parts of waterborne polyurethane, 0.03-0.05 parts of alkali, and 80-100 parts of water. The above technical scheme solves the problem of poor moisture resistance of corrugated paper in the prior art.

Description

Technical Field

[0001] The invention relates to the technical field of paper products, and in particular to moisture-proof corrugated paper and a preparation method thereof. Background Art

[0002] Corrugated paper is light, cheap, abundant and saves wood. Corrugated paper is made of surface paper and corrugated paper core bonded by adhesive. Its quality mainly depends on smoothness, moisture resistance and bonding strength. Smoothness refers to the flatness and smoothness of the surface of corrugated paper, which affects the appearance of the packaging box; moisture resistance affects the strength and service life of corrugated paper; bonding strength refers to the bonding strength between the layers of corrugated paperboard, which determines the structural stability of the corrugated paper.

[0003] The performance of the adhesive in corrugated paper greatly affects the performance of the corrugated paper. Starch is currently widely used as an adhesive, but starch has high hygroscopicity, resulting in poor moisture resistance of the prepared corrugated paper. Summary of the invention

[0004] The invention provides a moisture-proof corrugated paper and a preparation method thereof, which solves the problem of poor moisture-proof property of the corrugated paper in the related art.

[0005] The technical solution of the present invention is as follows:

[0006] A moisture-proof corrugated paper comprises, from top to bottom, an upper paper, a corrugated paper core and a lower paper, wherein the upper paper and the corrugated paper core are bonded by an adhesive, and the corrugated paper core and the lower paper are bonded by an adhesive, wherein the adhesives independently comprise the following components in parts by weight: 35-45 parts of corn starch, 10-30 parts of epoxy compound-modified corn starch, 1-2 parts of waterborne polyurethane, 0.03-0.05 parts of alkali and 80-100 parts of water.

[0007] As a further technical solution, the alkali includes one or both of sodium hydroxide and potassium hydroxide.

[0008] As a further technical solution, the raw materials of the epoxy compound-modified corn starch include epoxy compound and corn starch in a mass ratio of 3 to 8:30.

[0009] The present invention limits the raw materials of the epoxy compound-modified corn starch to the epoxy compound and corn starch in a mass ratio of 3 to 8:30, thereby further improving the moisture resistance and bursting strength of the corrugated paper.

[0010] As a further technical solution, the epoxy compound includes one or more of 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, and tetraethylene glycol diglycidyl ether.

[0011] As a further technical solution, the epoxy compound is 1,4-butanediol diglycidyl ether.

[0012] The present invention limits the epoxy compound to 1,4-butanediol diglycidyl ether, thereby further improving the moisture resistance and bursting strength of the corrugated paper.

[0013] As a further technical solution, the preparation method of the epoxy compound modified corn starch includes the following steps: adding a catalyst and an epoxy compound to a corn starch emulsion with a mass concentration of 30% to 40% while stirring, reacting, filtering, and drying to obtain epoxy compound modified corn starch.

[0014] As a further technical solution, the reaction is carried out in a nitrogen atmosphere.

[0015] As a further technical solution, the reaction temperature is 30-50°C and the reaction time is 18-25h.

[0016] As a further technical solution, the catalyst includes one or both of sodium hydroxide and potassium hydroxide.

[0017] As a further technical solution, the mass ratio of the corn starch to the epoxy compound modified corn starch is 8:3~5.

[0018] The present invention limits the mass ratio of corn starch to epoxy compound modified corn starch to 8:3-5, thereby further improving the moisture resistance and bursting strength of the corrugated paper.

[0019] The present invention also provides a method for preparing moisture-proof corrugated paper, comprising the following steps:

[0020] S1. After corn starch, epoxy-modified corn starch, alkali and water are uniformly mixed, water-based polyurethane is added and the mixture is continued to be mixed to obtain an adhesive;

[0021] S2. Apply the adhesive to the upper paper and the lower paper respectively, laminate the upper paper, the corrugated paper core and the lower paper, and dry them to obtain moisture-proof corrugated paper.

[0022] The working principle and beneficial effects of the present invention are:

[0023] The invention provides a moisture-proof corrugated paper, wherein the adhesive comprises corn starch, epoxy compound-modified corn starch, water-based polyurethane, alkali and water. The epoxy compound-modified corn starch and corn starch are compounded and used, which not only reduces the hygroscopicity of the starch, but also increases the cross-linking degree inside the adhesive, thereby improving the moisture resistance and bursting strength of the corrugated paper. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The waterborne polyurethane in the following examples and comparative examples is waterborne polyurethane HK718;

[0026] Corrugated paper is prepared by the following method:

[0027] The corrugated base paper is corrugated by a corrugated roller to obtain a corrugated paper core; three layers of surface paper and two layers of corrugated paper core are prepared, and the adhesive is applied at a rate of 25g / m 2 The amount of the coating agent is applied on the face paper, and the structure of face paper, corrugated paper core, face paper, corrugated paper core, and face paper is laminated from top to bottom, and the laminate is allowed to stand for 1.5 hours, and dried at 100° C. to obtain corrugated paper;

[0028] The preparation method of the adhesive is as follows:

[0029] Example 1

[0030] S1. Add 0.015 g of sodium hydroxide to 100 g of 30% corn starch aqueous emulsion while stirring, remove air with nitrogen, add 1 g of 1,6-hexanediol diglycidyl ether, heat to 40° C. and react for 20 h, filter, and dry to obtain epoxy compound-modified corn starch;

[0031] S2. After mixing 40 parts of corn starch, 10 parts of epoxy compound-modified corn starch, 0.04 parts of sodium hydroxide and 90 parts of water at 40° C. for 15 hours, 1.5 parts of waterborne polyurethane were added and the mixture was mixed for another 0.5 hours to obtain an adhesive.

[0032] Example 2

[0033] S1. Add 0.015 g of potassium hydroxide to 100 g of corn starch aqueous emulsion with a mass concentration of 35% while stirring, remove air with nitrogen, add 1 g of ethylene glycol diglycidyl ether, heat to 30° C. and react for 25 h, filter, and dry to obtain epoxy compound-modified corn starch;

[0034] S2. After mixing 35 parts of corn starch, 10 parts of epoxy compound-modified corn starch, 0.03 parts of sodium hydroxide and 80 parts of water at 40° C. for 15 hours, 1 part of waterborne polyurethane was added and the mixture was mixed for another 0.5 hours to obtain an adhesive.

[0035] Example 3

[0036] S1. Add 0.015 g of potassium hydroxide to 100 g of corn starch aqueous emulsion with a mass concentration of 40% while stirring, remove air with nitrogen, add 1 g of tetraethylene glycol diglycidyl ether, heat to 50° C. and react for 18 h, filter, and dry to obtain epoxy compound-modified corn starch;

[0037] S2. After mixing 45 parts of corn starch, 10 parts of epoxy compound-modified corn starch, 0.05 parts of potassium hydroxide and 100 parts of water at 40° C. for 15 hours, 2 parts of waterborne polyurethane were added and mixing was continued for 0.5 hours to obtain an adhesive.

[0038] Example 4

[0039] S1. Add 0.015 g of sodium hydroxide to 100 g of 30% corn starch aqueous emulsion while stirring, remove air with nitrogen, add 1 g of tetraethylene glycol diglycidyl ether, heat to 40° C. and react for 20 h, filter, and dry to obtain epoxy compound-modified corn starch;

[0040] S2. After mixing 40 parts of corn starch, 10 parts of epoxy compound-modified corn starch, 0.04 parts of sodium hydroxide and 90 parts of water at 40° C. for 15 hours, 1.5 parts of waterborne polyurethane were added and the mixture was mixed for another 0.5 hours to obtain an adhesive.

[0041] Example 5

[0042] S1. Add 0.015 g of sodium hydroxide to 100 g of 30% corn starch aqueous emulsion while stirring, remove air with nitrogen, add 1 g of 1,4-butanediol diglycidyl ether, heat to 40° C. and react for 20 h, filter, and dry to obtain epoxy compound-modified corn starch;

[0043] S2. After mixing 40 parts of corn starch, 10 parts of epoxy compound-modified corn starch, 0.04 parts of sodium hydroxide and 90 parts of water at 40° C. for 15 hours, 1.5 parts of waterborne polyurethane were added and the mixture was mixed for another 0.5 hours to obtain an adhesive.

[0044] Example 6

[0045] S1. Add 0.015 g of sodium hydroxide to 100 g of 30% corn starch aqueous emulsion while stirring, remove air with nitrogen, add 3 g of 1,4-butanediol diglycidyl ether, heat to 40° C. and react for 20 h, filter, and dry to obtain epoxy compound-modified corn starch;

[0046] S2. After mixing 40 parts of corn starch, 10 parts of epoxy compound-modified corn starch, 0.04 parts of sodium hydroxide and 90 parts of water at 40° C. for 15 hours, 1.5 parts of waterborne polyurethane were added and the mixture was mixed for another 0.5 hours to obtain an adhesive.

[0047] Example 7

[0048] S1. Add 0.015 g of sodium hydroxide to 100 g of 30% corn starch aqueous emulsion while stirring, remove air with nitrogen, add 5 g of 1,4-butanediol diglycidyl ether, heat to 40° C. and react for 20 h, filter, and dry to obtain epoxy compound-modified corn starch;

[0049] S2. After mixing 40 parts of corn starch, 10 parts of epoxy compound-modified corn starch, 0.04 parts of sodium hydroxide and 90 parts of water at 40° C. for 15 hours, 1.5 parts of waterborne polyurethane were added and the mixture was mixed for another 0.5 hours to obtain an adhesive.

[0050] Example 8

[0051] S1. Add 0.015 g of sodium hydroxide to 100 g of 30% corn starch aqueous emulsion while stirring, remove air with nitrogen, add 8 g of 1,4-butanediol diglycidyl ether, heat to 40° C. and react for 20 h, filter, and dry to obtain epoxy compound-modified corn starch;

[0052] S2. After mixing 40 parts of corn starch, 10 parts of epoxy compound-modified corn starch, 0.04 parts of sodium hydroxide and 90 parts of water at 40° C. for 15 hours, 1.5 parts of waterborne polyurethane were added and the mixture was mixed for another 0.5 hours to obtain an adhesive.

[0053] Example 9

[0054] S1. Add 0.015 g of sodium hydroxide to 100 g of 30% corn starch aqueous emulsion while stirring, remove air with nitrogen, add 10 g of 1,4-butanediol diglycidyl ether, heat to 40° C. and react for 20 h, filter, and dry to obtain epoxy compound-modified corn starch;

[0055] S2. After mixing 40 parts of corn starch, 10 parts of epoxy compound-modified corn starch, 0.04 parts of sodium hydroxide and 90 parts of water at 40° C. for 15 hours, 1.5 parts of waterborne polyurethane were added and the mixture was mixed for another 0.5 hours to obtain an adhesive.

[0056] Example 10

[0057] S1. Add 0.015 g of sodium hydroxide to 100 g of 30% corn starch aqueous emulsion while stirring, remove air with nitrogen, add 5 g of 1,4-butanediol diglycidyl ether, heat to 40° C. and react for 20 h, filter, and dry to obtain epoxy compound-modified corn starch;

[0058] S2. After mixing 40 parts of corn starch, 15 parts of epoxy compound-modified corn starch, 0.04 parts of sodium hydroxide and 90 parts of water at 40° C. for 15 hours, 1.5 parts of waterborne polyurethane were added and the mixture was mixed for another 0.5 hours to obtain an adhesive.

[0059] Embodiment 11

[0060] S1. Add 0.015 g of sodium hydroxide to 100 g of 30% corn starch aqueous emulsion while stirring, remove air with nitrogen, add 5 g of 1,4-butanediol diglycidyl ether, heat to 40° C. and react for 20 h, filter, and dry to obtain epoxy compound-modified corn starch;

[0061] S2. After mixing 40 parts of corn starch, 20 parts of epoxy compound-modified corn starch, 0.04 parts of sodium hydroxide and 90 parts of water at 40° C. for 15 hours, 1.5 parts of waterborne polyurethane were added and the mixture was mixed for another 0.5 hours to obtain an adhesive.

[0062] Example 12

[0063] S1. Add 0.015 g of sodium hydroxide to 100 g of 30% corn starch aqueous emulsion while stirring, remove air with nitrogen, add 5 g of 1,4-butanediol diglycidyl ether, heat to 40° C. and react for 20 h, filter, and dry to obtain epoxy compound-modified corn starch;

[0064] S2. After mixing 40 parts of corn starch, 25 parts of epoxy compound-modified corn starch, 0.04 parts of sodium hydroxide and 90 parts of water at 40° C. for 15 hours, 1.5 parts of waterborne polyurethane were added and the mixture was mixed for another 0.5 hours to obtain an adhesive.

[0065] Example 13

[0066] S1. Add 0.015 g of sodium hydroxide to 100 g of 30% corn starch aqueous emulsion while stirring, remove air with nitrogen, add 5 g of 1,4-butanediol diglycidyl ether, heat to 40° C. and react for 20 h, filter, and dry to obtain epoxy compound-modified corn starch;

[0067] S2. After mixing 40 parts of corn starch, 30 parts of epoxy compound-modified corn starch, 0.04 parts of sodium hydroxide and 90 parts of water at 40° C. for 15 hours, 1.5 parts of waterborne polyurethane were added and the mixture was mixed for another 0.5 hours to obtain an adhesive.

[0068] Comparative Example 1

[0069] S1. Add 0.015 g of sodium hydroxide to 100 g of 30% corn starch aqueous emulsion while stirring, remove air with nitrogen, add 1 g of 1,6-hexanediol diglycidyl ether, heat to 40° C. and react for 20 h, filter, and dry to obtain epoxy compound-modified corn starch;

[0070] S2. After mixing 50 parts of epoxy compound-modified corn starch, 0.04 parts of sodium hydroxide and 90 parts of water at 40° C. for 15 hours, 1.5 parts of waterborne polyurethane were added and the mixture was mixed for another 0.5 hours to obtain an adhesive.

[0071] Comparative Example 2

[0072] 50 parts of corn starch, 0.04 parts of sodium hydroxide and 90 parts of water were mixed at 40° C. for 15 hours, and then 1.5 parts of waterborne polyurethane were added and mixed for another 0.5 hours to obtain an adhesive.

[0073] Comparative Example 3

[0074] 50 parts of corn starch, 0.33 parts of 1,6-hexanediol diglycidyl ether, 0.04 parts of sodium hydroxide and 90 parts of water were mixed at 40° C. for 15 hours, and then 1.5 parts of waterborne polyurethane were added and mixed for a further 0.5 hours to obtain an adhesive.

[0075] The corrugated paper obtained in Examples 1 to 13 and Comparative Examples 1 to 3 was tested for bonding strength according to the method in GB / T 6548-2011 "Determination of bonding strength of corrugated paperboard". Before the test, the corrugated paper was placed in a constant temperature and humidity chamber at a humidity of 40% RH and a temperature of 35°C and a humidity of 80% RH and a temperature of 35°C for 12 hours respectively; and the bursting strength was tested according to the method in GB / T 6545-1998 "Determination of bursting strength of corrugated paperboard". The test results are recorded in Table 1.

[0076] Table 1 Moisture resistance and bursting strength of corrugated paper

[0077]

[0078] It can be seen from Table 1 that the corrugated paper provided by the present invention has good moisture resistance and high bursting strength.

[0079] Compared with Comparative Examples 1-3, Examples 1-13 use epoxy-modified corn starch and corn starch, Comparative Example 1 uses epoxy-modified corn starch, Comparative Example 2 uses corn starch, and Comparative Example 3 directly mixes rice starch and 1,6-hexanediol diglycidyl ether. The bonding strength and bursting strength of the corrugated paper obtained in Examples 1-13 are higher than those in Comparative Examples 1-3, indicating that the composite use of epoxy-modified corn starch and corn starch can improve the moisture resistance and bursting strength of corrugated paper.

[0080] The bonding strength and bursting strength of the corrugated paper obtained in Examples 6 to 8 are higher than those in Examples 5 and 9, indicating that the mass ratio of the epoxy compound to corn starch is 3 to 8:30, which can further improve the moisture resistance and bursting strength of the corrugated paper.

[0081] The bonding strength and bursting strength of the corrugated paper obtained in Examples 10 to 12 are higher than those in the other examples, indicating that the mass ratio of corn starch to epoxy compound-modified corn starch is 8:3 to 5, which can further improve the moisture resistance and bursting strength of the corrugated paper.

[0082] The above are only 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 in the protection scope of the present invention.

Claims

1. A moisture-proof corrugated paper, comprising, from top to bottom, an upper paper, a corrugated paper core and a lower paper, wherein the upper paper and the corrugated paper core are bonded by an adhesive, and the corrugated paper core and the lower paper are bonded by an adhesive, characterized in that: The adhesive is independently composed of the following components in parts by mass: 35-45 parts of corn starch, 10-30 parts of epoxy compound-modified corn starch, 1-2 parts of waterborne polyurethane, 0.03-0.05 parts of alkali, and 80-100 parts of water; the raw materials of the epoxy compound-modified corn starch include epoxy compound and corn starch in a mass ratio of 3-8:30; The epoxy compound includes one or more of 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, and tetraethylene glycol diglycidyl ether; The preparation method of the epoxy compound modified corn starch comprises the following steps: adding a catalyst and an epoxy compound to a corn starch emulsion with a mass concentration of 30% to 40% while stirring, reacting, filtering, and drying to obtain the epoxy compound modified corn starch; The reaction temperature is 30-50° C., and the reaction time is 18-25 hours.

2. The moisture-proof corrugated paper according to claim 1, characterized in that: The epoxy compound is 1,4-butanediol diglycidyl ether.

3. The moisture-proof corrugated paper according to claim 1, characterized in that: The reaction was carried out under nitrogen atmosphere.

4. The moisture-proof corrugated paper according to claim 1, characterized in that: The catalyst includes one or both of sodium hydroxide and potassium hydroxide.

5. The moisture-proof corrugated paper according to claim 1, characterized in that: The mass ratio of the corn starch to the epoxy compound modified corn starch is 8:3-5.

6. A method for preparing moisture-proof corrugated paper according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. After corn starch, epoxy-modified corn starch, alkali and water are uniformly mixed, water-based polyurethane is added and the mixture is continued to be mixed to obtain an adhesive; S2. Apply the adhesive to the upper paper and the lower paper respectively, laminate the upper paper, the corrugated paper core and the lower paper, and dry them to obtain moisture-proof corrugated paper.

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