Quick packaging hot melt adhesive for paper products

Abstract

The invention relates to the technical field of hot melt adhesives, in particular to a rapid packaging hot melt adhesive for paper products. The adhesive is prepared from the following raw materials in percentage by weight: 20-60% of high molecular weight resin, 10-20% of wax, 2-15% of oil, 28-60% of tackifying resin, 0.1-1% of an antioxidant and 5-15% of polyester polyol, the wax comprises a mixture of vegetable wax, mineral wax and microcrystalline wax, the tackifying resin is modified polyurethane resin, and the modified polyurethane resin is prepared by modifying a catalyst triethylene diamine and a chain extender 1, 4-butanediol. The prepared rapid packaging hot melt adhesive for the paper products can be better in cohesiveness with the paper products, the viscosity and strength of the hot melt adhesive cannot be lost due to the temperature, and better stability is achieved.

Description

Technical Field

[0001] This invention relates to the field of hot melt adhesive technology, and more specifically, to a hot melt adhesive for rapid packaging of paper products. Background Technology

[0002] Hot melt adhesive for rapid paper packaging is a solid adhesive specifically designed for paper products. It is applied to the material surface after being heated to melt (typically 150-180℃), and then rapidly solidifies upon cooling (usually 1-20 seconds), forming a high-strength bond. It can bond paper, cardboard, laminated materials, plastic films, etc., with a peel strength exceeding 12 kg / cm². It is solvent-free and free of volatile organic compounds (VOCs), meeting food-grade safety standards and suitable for food and pharmaceutical packaging.

[0003] Ordinary hot melt adhesives work well for bonding white cardboard, but their adhesion to metal substrates is poor, and the adhesive is prone to peeling and separation. This is because when hot melt adhesive is sprayed onto a metal substrate at high temperatures, it is not fully wetted, the temperature drops rapidly, the adhesive hardens, and the bond fails.

[0004] In the prior art, hot melt adhesives for packaging have the following disadvantages: (1) Incompatibility between the substrate and the hot melt adhesive: Different materials require the selection of appropriate hot melt adhesive types, and the characteristics of the substrate have a significant impact on the bonding effect. (2) Too low a temperature will cause the hot melt adhesive to fail to melt fully, resulting in insufficient fluidity and wetting; too high a temperature may cause the hot melt adhesive to soften excessively or decompose, losing its stickiness and strength. (3) Changes in hot melt adhesive properties: Thermal degradation or oxidative degradation may cause changes in the properties of the hot melt adhesive, affecting the bonding effect. Summary of the Invention

[0005] This invention provides a hot melt adhesive for rapid packaging of paper products. The resulting hot melt adhesive for rapid packaging of paper products has better adhesion to paper products, does not lose its adhesiveness and strength due to temperature, and has better stability.

[0006] In a first aspect, the present invention provides a hot melt adhesive for rapid packaging of paper products, which is made from the following raw materials in weight percentages: 20-60% high molecular weight resin, 10-20% wax, 2-15% oil, 28-60% tackifying resin, 0.1-1% antioxidant, and 5-15% polyester polyol. The wax includes a mixture of plant wax, mineral wax and microcrystalline wax. The tackifying resin is a modified polyurethane resin, which is prepared by modification with the catalyst triethylenediamine and the chain extender 1,4-butanediol.

[0007] Preferably, it is made from the following raw materials in weight percentage: 28-60% high molecular weight resin, 15-20% wax, 6-15% oil, 42-60% tackifying resin, 0.8-1% antioxidant, and 8-15% polyester polyol.

[0008] Preferably, it is made from the following raw materials in weight percentage: 35-55% high molecular weight resin, 15-18% wax, 6-12% oil, 48-52% tackifying resin, 0.8-1% antioxidant, and 8-12% polyester polyol.

[0009] Preferably, it is made from the following raw materials in weight percentage: 49% high molecular weight resin, 16% wax, 10% oil, 50% tackifying resin, 1% antioxidant, and 11% polyester polyol.

[0010] Preferably, the mass ratio of plant wax, mineral wax and microcrystalline wax in the mixture is 1-2:1-3:2-5.

[0011] Preferably, the method for preparing modified polyurethane resin includes the following steps: A1: Mix polyol with isocyanate, add triethylenediamine, heat to 65-80℃ under nitrogen protection, stir and react for 1-5 hours to obtain prepolymer; A2: Dissolve 1,4-butanediol in acetone or tetrahydrofuran to prepare a mixed solution; A3: Slowly add the prepared mixed solution dropwise into the prepolymer and continue stirring at 60-80℃ for 1-3 hours to obtain the hot melt adhesive for rapid packaging of paper products.

[0012] Preferably, the high molecular weight resin includes one or more of the following: copolymer resin of ethylene and vinyl acetate, copolymer resin of ethylene and propylene, copolymer resin of ethylene and 1-octene, copolymer resin of ethylene and fluoroolefin or copolymer resin of fluoroolefin and polybasic acid, and ternary copolymer resin of ethylene, propylene and butene.

[0013] Preferably, the tackifying resin also includes one or more of the following: rosin resins, polyterpene resins, dammar resins, coumarone-indene resins, polystyrene resins, and hydrogenated petroleum resins.

[0014] Preferably, the antioxidant includes one or more of diethylhexyl phosphite, dilauryl thiodipropionate, distearate thiodipropionate, tert-butyl-p-cresol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and octadecyl alcohol ester.

[0015] Preferably, the oil includes one or more of white oil, rubber oil, mineral oil, or polyisobutylene.

[0016] Secondly, the present invention provides a method for preparing a hot melt adhesive for rapid packaging of paper products, comprising the following steps: (1) Add the raw materials high molecular weight resin, wax, oil, tackifying resin, antioxidant and polyester polyol to the container according to the raw material metering ratio; gradually turn on the stirring during the feeding process and raise the temperature to 120-150℃. After reaching the temperature, the stirring speed is 300-800r / min. (2) After mixing the raw materials, heat to 140-160℃ and stir for 30-40 minutes; (3) Cool down to 100-130℃, add the wax, turn on the vacuum decompression, the vacuum degree is -0.08MPa, after 30-40min, release the vacuum, level, granulate and package.

[0017] Thirdly, this invention provides an application of a hot melt adhesive for rapid paper packaging in industrial packaging of paper bags, paper boxes, and straws.

[0018] In summary, the present invention has the following beneficial effects: 1. The hot melt adhesive prepared in this invention has advantages in paper packaging, such as cartons, boxes, and bags, including rapid curing, environmental friendliness, and high bonding strength. By adding high molecular weight resin, wax, oil, tackifying resin, antioxidant, and polyester polyol, the mechanical stability and bonding strength of the hot melt adhesive are improved, ensuring that the paper products are impact-resistant and tear-resistant when used in paper products.

[0019] 2. In this invention, the modified polyurethane resin is added in the prepolymerization stage by adding triethylenediamine to catalyze the reaction between isocyanate and polyol, while 1,4-butanediol is added as a chain extender in a subsequent stage to extend the molecular chain. Triethylenediamine forms a complex with the -NCO group through the nitrogen atom in its cage structure, which reduces the reaction activation energy and preferentially catalyzes the reaction between isocyanate and hydroxyl group. 3. The hot melt adhesive for rapid packaging of paper products prepared by this invention has a simple preparation process, no pollutants or dust emissions, no irritating odor when used at high temperatures, does not produce filaments, and has good environmental performance.

[0020] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the scope of protection of the present invention. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments can be obtained from commercially available sources.

[0022] Example Preparation Example A method for preparing a modified polyurethane resin includes the following steps: A1: Mix 12g of polyol with 25g of isocyanate, add 21g of triethylenediamine, heat to 65℃ under nitrogen protection, stir and react for 2h to obtain the prepolymer; A2: Dissolve 42g of 1,4-butanediol in 100mL of acetone to prepare a mixed solution; A3: Slowly add the prepared mixed solution dropwise into the prepolymer and continue stirring at 80°C for 1 hour to obtain the hot melt adhesive for rapid packaging of paper products.

[0023] Example 1 A hot melt adhesive for rapid packaging of paper products is made from the following raw materials by weight percentage: 20% high molecular weight resin, 10% wax, 2% oil, 28% tackifying resin, 0.2% antioxidant, and 5% polyester polyol; the wax includes a mixture of plant wax, mineral wax, and microcrystalline wax, wherein the mass ratio of plant wax, mineral wax, and microcrystalline wax in the mixture is 1:1:2. The modified polyurethane resin is prepared in the example; the high molecular weight resin is a copolymer resin of ethylene and vinyl acetate; the tackifying resin also includes a mixture of rosin resin and polyterpene resin in a mass ratio of 1:2; the antioxidant is diethylhexyl phosphite; and the oil is rubber oil.

[0024] A method for preparing a hot melt adhesive for rapid packaging of paper products includes the following steps: (1) Add the raw materials high molecular weight resin, wax, oil, tackifying resin, antioxidant and polyester polyol to the container according to the raw material metering ratio; gradually turn on the stirring during the feeding process and raise the temperature to 120°C. After reaching the temperature, the stirring speed is 300r / min. (2) After mixing the raw materials, heat to 140℃ and stir for 30 minutes; (3) Cool down to 100°C, add the wax, turn on the vacuum decompression, the vacuum degree is -0.08MPa, after 30 minutes, release the vacuum, level, granulate and package.

[0025] Example 2 A hot melt adhesive for rapid packaging of paper products is made from the following raw materials by weight percentage: 32% high molecular weight resin, 12% wax, 5% oil, 35% tackifying resin, 0.5% antioxidant, and 8% polyester polyol; the wax includes a mixture of plant wax, mineral wax, and microcrystalline wax, wherein the mass ratio of plant wax, mineral wax, and microcrystalline wax in the mixture is 1:2:3. The modified polyurethane resin is prepared in the example; the high molecular weight resin is a copolymer resin of ethylene and vinyl acetate; the tackifying resin also includes a mixture of rosin resin and polyterpene resin in a mass ratio of 1:1; the antioxidant is diethylhexyl phosphite; and the oil is rubber oil.

[0026] A method for preparing a hot melt adhesive for rapid packaging of paper products includes the following steps: (1) Add the raw materials high molecular weight resin, wax, oil, tackifying resin, antioxidant and polyester polyol to the container according to the raw material metering ratio; gradually turn on the stirring during the feeding process and raise the temperature to 130℃. After reaching the temperature, the stirring speed is 400r / min. (2) After mixing the raw materials, heat to 150℃ and stir for 30 minutes; (3) Cool down to 100°C, add the wax, turn on the vacuum decompression, the vacuum degree is -0.08MPa, after 30 minutes, release the vacuum, level, granulate and package.

[0027] Example 3 A hot melt adhesive for rapid packaging of paper products is made from the following raw materials by weight percentage: 40% high molecular weight resin, 15% wax, 8% oil, 32% tackifying resin, 0.2% antioxidant, and 7% polyester polyol; the wax includes a mixture of plant wax, mineral wax, and microcrystalline wax, wherein the mass ratio of plant wax, mineral wax, and microcrystalline wax in the mixture is 1:3:2. The modified polyurethane resin is prepared in the example; the high molecular weight resin is a copolymer resin of ethylene and vinyl acetate; the tackifying resin also includes a mixture of rosin resin and polyterpene resin in a mass ratio of 1:3; the antioxidant is diethylhexyl phosphite; and the oil is rubber oil.

[0028] A method for preparing a hot melt adhesive for rapid packaging of paper products includes the following steps: (1) Add the raw materials high molecular weight resin, wax, oil, tackifying resin, antioxidant and polyester polyol to the container according to the raw material metering ratio; gradually turn on the stirring during the feeding process and raise the temperature to 150℃. After reaching the temperature, the stirring speed is 800r / min. (2) After mixing the raw materials, heat to 160℃ and stir for 40 minutes; (3) Cool down to 130°C, add the wax, turn on the vacuum decompression, the vacuum degree is -0.08MPa, after 30 minutes, release the vacuum, level, granulate and package.

[0029] Example 4 A hot melt adhesive for rapid packaging of paper products is made from the following raw materials by weight percentage: 50% high molecular weight resin, 15% wax, 10% oil, 36% tackifying resin, 0.8% antioxidant, and 12% polyester polyol; the wax includes a mixture of plant wax, mineral wax, and microcrystalline wax, wherein the mass ratio of plant wax, mineral wax, and microcrystalline wax in the mixture is 2:1:2. The modified polyurethane resin is prepared in the example; the high molecular weight resin is a copolymer resin of ethylene and vinyl acetate; the tackifying resin also includes a mixture of rosin resin and polyterpene resin in a mass ratio of 1:1; the antioxidant is diethylhexyl phosphite; and the oil is rubber oil.

[0030] A method for preparing a hot melt adhesive for rapid packaging of paper products includes the following steps: (1) Add the raw materials high molecular weight resin, wax, oil, tackifying resin, antioxidant and polyester polyol to the container according to the raw material metering ratio; gradually turn on the stirring during the feeding process and raise the temperature to 150℃. After reaching the temperature, the stirring speed is 800r / min. (2) After mixing the raw materials, heat to 160℃ and stir for 40 minutes; (3) Cool down to 130°C, add the wax, turn on the vacuum decompression, the vacuum degree is -0.08MPa, after 30 minutes, release the vacuum, level, granulate and package.

[0031] Example 5 A hot melt adhesive for rapid packaging of paper products is made from the following raw materials by weight percentage: 60% high molecular weight resin, 10% wax, 10% oil, 20% tackifying resin, 0.8% antioxidant, and 5% polyester polyol; the wax includes a mixture of plant wax, mineral wax, and microcrystalline wax, wherein the mass ratio of plant wax, mineral wax, and microcrystalline wax in the mixture is 1:1:5. The modified polyurethane resin is prepared in the example; the high molecular weight resin is a copolymer resin of ethylene and vinyl acetate; the tackifying resin also includes a mixture of rosin resin and polyterpene resin in a mass ratio of 1:3; the antioxidant is diethylhexyl phosphite; and the oil is rubber oil.

[0032] A method for preparing a hot melt adhesive for rapid packaging of paper products includes the following steps: (1) Add the raw materials high molecular weight resin, wax, oil, tackifying resin, antioxidant and polyester polyol to the container according to the raw material metering ratio; gradually turn on the stirring during the feeding process and raise the temperature to 140℃. After reaching the temperature, the stirring speed is 600r / min. (2) After mixing the raw materials, heat to 150℃ and stir for 30 minutes; (3) Cool down to 120°C, add the wax, turn on the vacuum decompression, the vacuum degree is -0.08MPa, after 30 minutes, release the vacuum, level, granulate and package.

[0033] Comparative Example 1 Comparative Example 1 is a typical hot melt adhesive.

[0034] Comparative Example 2 Comparative Example 2 is a common SIS-type hot melt pressure-sensitive adhesive.

[0035] Performance testing: 1. The softening point, melt viscosity, brittle temperature, and thermal stability were all tested in accordance with the relevant clauses and testing methods of HG / T3698-2002 EVA hot melt adhesives.

[0036] 2. Curing time refers to the time taken after the adhesive is melted and scraped onto a piece of cardboard, and then another piece of paper is pasted onto it. The time is recorded from the time the pasting is completed, peeling it off from one end until a piece of the substrate is cut. This indicates that the adhesive has cured.

[0037] Table 1 Performance Test Results As shown in Table 1, the hot melt adhesive for rapid paper packaging prepared by the present invention has better adhesion to paper products, does not lose its adhesiveness and strength due to temperature, and has better stability.

[0038] The above description is merely an exemplary embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A hot melt adhesive for rapid packaging of paper products, characterized in that, It is made from the following raw materials by weight percentage: 20-60% high molecular weight resin, 10-20% wax, 2-15% oil, 28-60% tackifying resin, 0.1-1% antioxidant, 5-15% polyester polyol. The wax includes a mixture of plant wax, mineral wax and microcrystalline wax. The tackifying resin is a modified polyurethane resin, which is prepared by modification with the catalyst triethylenediamine and the chain extender 1,4-butanediol.

2. The hot melt adhesive for rapid packaging of paper products according to claim 1, characterized in that, It is made from the following raw materials by weight percentage: 28-60% high molecular weight resin, 15-20% wax, 6-15% oil, 42-60% tackifying resin, 0.8-1% antioxidant, and 8-15% polyester polyol.

3. The hot melt adhesive for rapid packaging of paper products according to claim 1, characterized in that, The mass ratio of plant wax, mineral wax and microcrystalline wax in the mixture is 1-2:1-3:2-5.

4. The hot melt adhesive for rapid packaging of paper products according to claim 1, characterized in that, A method for preparing modified polyurethane resin includes the following steps: A1: Mix polyol with isocyanate, add triethylenediamine, heat to 65-80℃ under nitrogen protection, stir and react for 1-5 hours to obtain prepolymer; A2: Dissolve 1,4-butanediol in acetone or tetrahydrofuran to prepare a mixed solution; A3: Slowly add the prepared mixed solution dropwise into the prepolymer and continue stirring at 60-80℃ for 1-3 hours to obtain the hot melt adhesive for rapid packaging of paper products.

5. The hot melt adhesive for rapid packaging of paper products according to claim 1, characterized in that, High molecular weight resins include one or more of the following: copolymers of ethylene and vinyl acetate, copolymers of ethylene and propylene, copolymers of ethylene and 1-octene, copolymers of ethylene and fluoroolefins or copolymers of fluoroolefins and polybasic acids, and ternary copolymers of ethylene, propylene, and butene.

6. The hot melt adhesive for rapid packaging of paper products according to claim 1, characterized in that, Tackifying resins also include one or more of the following: rosin resins, polyterpene resins, dammar resins, coumarone-indene resins, polystyrene resins, and hydrogenated petroleum resins.

7. The hot melt adhesive for rapid packaging of paper products according to claim 1, characterized in that, Antioxidants include one or more of diethylhexyl phosphite, dilauryl thiodipropionate, distearate thiodipropionate, tert-butyl-p-cresol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and octadecyl alcohol ester.

8. The hot melt adhesive for rapid packaging of paper products according to claim 1, characterized in that, Oils include one or more of white oil, rubber oil, mineral oil, or polyisobutylene.

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