Water-washing automatic peeling type adhesive sticker

Abstract

The present application relates to the technical field of not dry glue, specifically relates to a kind of water-washing automatic shedding type not dry glue.The specific technical scheme is: a kind of water-washing automatic shedding type not dry glue, including adhesive layer and the label paper of setting in adhesive layer one side, the other side of adhesive layer is provided with recess along its length direction, recess is provided with shedding layer, shedding layer and adhesive layer are fixed by the way of chemical crosslinking between, the shedding layer is self-dissolution and occurs swelling deformation when meeting water.The present application solves the problem that dairy product bottle is recovered, and it is difficult to clean, and the cost is high.

Description

Technical Field

[0001] This invention relates to the field of self-adhesive technology, and more specifically to a water-washable, automatically peeling self-adhesive. Background Technology

[0002] After dairy companies recycle milk bottles, the labels need to be removed. Currently, manual removal is commonly used, which is inefficient and leaves adhesive residue on the bottle surface. Another method uses specialized adhesive removers, but this generates large amounts of wastewater, which causes environmental pollution if discharged directly. Treated wastewater requires large quantities of reagents and also produces waste liquid, making it time-consuming and costly. Therefore, there is an urgent need for a self-adhesive label that can be quickly removed by washing without damaging the label paper. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a water-washable, automatically detachable self-adhesive label, which solves the problems of difficult and costly cleaning after dairy product bottles are recycled.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] This invention discloses a water-washable, self-removing self-adhesive label, comprising an adhesive layer and a label paper disposed on one side of the adhesive layer. A groove is provided on the other side of the adhesive layer along its length, and a release layer is disposed in the groove. The release layer and the adhesive layer are fixed by chemical cross-linking. The release layer self-dissolves and expands and deforms when exposed to water.

[0006] Preferably, the adhesive layer comprises, by mass percentage, 0.5-5% emulsifier, 1-8% acrylic acid or methacrylic acid, 5-20% methyl methacrylate, 10-40% butyl acrylate, 0.1-0.5% initiator, and 40-80% deionized water.

[0007] Preferably, the initiator is potassium persulfate, sodium persulfate, or benzoyl peroxide.

[0008] Preferably, the emulsifier is polyoxyethylene stearate or sodium allyl ether sulfonate.

[0009] Preferably, the exfoliating layer comprises, by mass percentage, 10-15% water-soluble polysaccharide, 7-15% calcium chloride, 10-65% colloid, 3-5% N-hydroxymethylacrylamide, 15-20% epoxy resin, and 5-10% styrene.

[0010] Preferably, the water-soluble polysaccharide includes one or more of sodium alginate, hyaluronic acid, cellulose, chitin, and chitosan.

[0011] Preferably, the colloid includes one or more of gelatin, pectin, konjac gum, carrageenan, and gellan gum.

[0012] Accordingly, a method for preparing the above-mentioned water-washable self-removing adhesive includes the following steps:

[0013] (1) Dissolve the emulsifier in water, then add acrylic acid or methacrylic acid, methyl methacrylate and butyl acrylate for pre-emulsification to obtain an emulsion;

[0014] (2) Heat 1 / 4 to 1 / 3 of the emulsion to 65 to 75°C, then add 1 / 4 to 1 / 3 of the initiator and react until the solution becomes clear;

[0015] (3) Heat the solution obtained in step (2) to 85-100°C, and add the remaining emulsion dropwise into the reaction system. After the dropwise addition is complete, add the remaining initiator and adjust the pH value to neutral to obtain the liquid adhesive layer material.

[0016] Preferably, the preparation process of the exfoliation layer includes the following steps:

[0017] (a) Add water-soluble polysaccharide, calcium chloride and colloid to water to swell for 1-2 hours, heat to 35-50°C and let stand for 6-12 hours to obtain gel solution;

[0018] (b) Dissolve epoxy resin in an organic solvent, add styrene and N-hydroxymethylacrylamide, mix well to obtain an epoxy resin solution for later use;

[0019] (c) The liquid adhesive layer material obtained in step (3) is coated to prepare an adhesive layer. At the same time, a groove is rolled out along its length at the center of the adhesive layer. The epoxy resin solution prepared in step (b) is coated in the groove and kept at 85-100°C for 2-4 hours.

[0020] (d) After cooling to 40-50°C, apply the gel solution and cover the entire groove.

[0021] Preferably, the organic solvent includes one of n-butanol, ethanol, and acetone.

[0022] The present invention has the following beneficial effects:

[0023] This invention involves coating a release layer onto the adhesive surface of the self-adhesive label. The release layer is mainly composed of a gel solution and an epoxy resin solution, with the epoxy resin solution positioned between the gel solution and the adhesive layer. Through a cross-linking grafting reaction, the bonding strength between the adhesive layer and the release layer is increased. Simultaneously, since the gel solution dissolves in water, the self-adhesive label on the milk bottle will automatically detach after soaking in water, eliminating the need for other reagents or manual adhesive removal. Furthermore, no adhesive residue remains on the milk bottle, thus solving the problems of difficult and costly cleaning of recycled dairy bottles. Detailed Implementation

[0024] 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.

[0025] Unless otherwise specified, the technical means used in the implementation examples are conventional means well known to those skilled in the art.

[0026] 1. The present invention provides a water-washable, self-removing self-adhesive label, comprising an adhesive layer and a label paper disposed on one side of the adhesive layer, wherein a groove is provided on the other side of the adhesive layer along its length, and a release layer is disposed in the groove, wherein the release layer and the adhesive layer are fixed by chemical cross-linking, and the release layer self-dissolves and expands and deforms upon contact with water.

[0027] Furthermore, by mass percentage, the adhesive layer comprises 0.5-5% emulsifier, 1-8% acrylic acid or methacrylic acid, 5-20% methyl methacrylate, 10-40% butyl acrylate, 0.1-0.5% initiator, and 40-80% deionized water.

[0028] Furthermore, the initiator is potassium persulfate, sodium persulfate, or benzoyl peroxide.

[0029] Furthermore, the emulsifier is polyoxyethylene stearate or sodium allyl ether sulfonate.

[0030] Furthermore, by mass percentage, the exfoliated layer comprises 10-15% water-soluble polysaccharide, 7-15% calcium chloride, 10-65% colloid, 3-5% N-hydroxymethylacrylamide, 15-20% epoxy resin, and 5-10% styrene.

[0031] The water-soluble polysaccharide comprises one or more of sodium alginate, hyaluronic acid, cellulose, chitin, and chitosan. The colloid comprises one or more of gelatin, pectin, konjac gum, carrageenan, and gellan gum. In this invention, mixing the water-soluble polysaccharide with the colloid and calcium chloride forms a dense and stable network structure, which improves the adhesion of the release layer. Simultaneously, it readily dissolves in water, facilitating the removal of the adhesive from the baby bottle.

[0032] Meanwhile, the epoxy resin used can undergo cross-linking reactions with methacrylic acid, styrene, butyl acrylate and initiators, thereby making the bond between the adhesive layer and the release layer tighter and preventing delamination between the adhesive layer and the release layer.

[0033] 2. This invention also discloses a method for preparing a water-washable, self-removing self-adhesive label, wherein the preparation of the adhesive layer includes the following steps:

[0034] (1) Dissolve the emulsifier in water, then add acrylic acid or methacrylic acid, methyl methacrylate and butyl acrylate for pre-emulsification to obtain an emulsion;

[0035] (2) Heat 1 / 4 to 1 / 3 of the emulsion to 65 to 75°C, then add 1 / 4 to 1 / 3 of the initiator and react until the solution becomes clear;

[0036] (3) Heat the solution obtained in step (2) to 85-100℃, and add the remaining emulsion dropwise to the reaction system. After the addition is complete, add the remaining initiator and adjust the pH value to neutral to obtain the liquid adhesive layer material. Sodium bicarbonate can be used to adjust the pH value of the reaction system.

[0037] The preparation process of the exfoliated layer includes the following steps:

[0038] (a) Add water-soluble polysaccharide, calcium chloride and colloid to water to swell for 1-2 hours, heat to 35-50°C and let stand for 6-12 hours to obtain gel solution.

[0039] (b) Dissolve epoxy resin in an organic solvent, add styrene and N-hydroxymethylacrylamide, mix well to obtain an epoxy resin solution for later use; the organic solvent includes one of n-butanol, ethanol and acetone.

[0040] (c) Prepare an adhesive layer by coating the liquid adhesive layer material obtained in step (3) using a coating method (such as casting process, roller coating process, doctor blade coating process, etc.). At the same time, roll a groove along the length of the adhesive layer at its center, and coat the groove with the epoxy resin solution prepared in step (b). Keep it at a temperature of 85-100℃ for 2-4 hours. It should be noted that: when the adhesive layer is in a semi-solid state, roll the groove, then coat with epoxy resin solution, and heat and keep it at a temperature of 85-100℃ to allow the epoxy resin to undergo a cross-linking and grafting reaction with the methacrylic acid, styrene, butyl acrylate and initiator in the adhesive layer, thereby weakening the boundary between the adhesive layer and the peeling layer; at the same time, the added N-hydroxymethylacrylamide has more polar groups, which can cross-link with the hydrophilic groups in the adhesive layer, thereby improving the bonding strength of the self-adhesive.

[0041] (d) After the above cross-linking reaction is completed, the temperature is lowered to 40-50°C, the gel solution is applied and the entire groove is filled. After cooling, release paper is applied to one side of the peeling layer to obtain a self-removing adhesive when exposed to water.

[0042] The present invention will be further described below with reference to specific embodiments.

[0043] Example

[0044] 1. The proportions of the adhesive layer are shown in Table 1 below.

[0045] Table 1. Adhesive layer mix proportions (%)

[0046]

[0047] 2. The formulation of the release layer is shown in Table 2 below. Comparative Example 1 is an example without a release layer; Comparative Example 2 is an example where the release layer is applied directly to the adhesive layer without creating a groove; Comparative Example 3 is an example where the epoxy resin solution covers the entire groove, and the gel solution is applied to the raised surfaces on both sides of the groove and to the epoxy resin layer; Comparative Example 4 is an example where epoxy resin and gel solution are mixed evenly and then applied to the groove; and Comparative Example 5 is an example where the epoxy resin and gel solution are mixed evenly and then applied directly to the adhesive layer without creating a groove.

[0048] Table 2. Proportion of detached layer (%)

[0049]

[0050] 3. The peel strength between double-sided adhesive tape and stainless steel plate was tested according to Method 3 in GB / T2792-2014: Test method for 180° peel strength between double-sided adhesive tape and transfer adhesive tape and stainless steel plate. The peel strength is denoted as peel strength A. The larger the peel strength A is, the better the adhesive performance of the self-adhesive tape. The test results are shown in Table 3.

[0051] Table 3. Peel strength test results between self-adhesive labels and stainless steel plates

[0052]

[0053]

[0054] 4. The self-adhesive labels prepared in groups 1 and 2 and comparative examples 1-3 were affixed to milk bottles and left for 12-24 hours. Then, they were immersed in ordinary water and water at a temperature of 40-50℃ to test the peeling of the self-adhesive labels. The results are shown in Table 4 below.

[0055] Table 4. Adhesive Label Peeling Status

[0056]

[0057] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A water wash-off self-removing type adhesive label, characterized by: The label paper comprises a bonding layer and a label paper arranged on one side of the bonding layer, the other side of the bonding layer is provided with a groove along the length direction of the bonding layer, and a falling-off layer is arranged in the groove, the falling-off layer and the bonding layer are fixed by chemical cross-linking, the falling-off layer is self-dissolved and swelled by water; According to the mass percentage, the falling-off layer comprises 10-15% of water-soluble polysaccharide, 7-15% of calcium chloride, 10-65% of colloid, 3-5% of N-hydroxymethyl acrylamide, 15-20% of epoxy resin and 5-10% of styrene; The water-soluble polysaccharide comprises a mixture of one or more of sodium alginate, hyaluronic acid, cellulose, chitin and chitosan; and the colloid comprises a mixture of one or more of gelatin, pectin, konjac gum, carrageenan and gellan gum.

2. The water washable automatic release adhesive according to claim 1, characterized in that: According to the mass percentage, the bonding layer comprises 0.5-5% of emulsifier, 1-8% of acrylic acid or methacrylic acid, 5-20% of methyl methacrylate, 10-40% of butyl acrylate, 0.1-0.5% of initiator and 40-80% of deionized water.

3. The water-activated, self-removing adhesive of claim 2, wherein: The initiator is potassium persulfate or sodium persulfate or benzoyl peroxide.

4. The water-activated, self-removing adhesive of claim 2, wherein: The emulsifier is polyoxyethylene stearate or sodium allyl ether sulfonate.

5. A method for preparing the water-washable self-removing type pressure-sensitive adhesive according to any one of claims 1 to 4, characterized by: The preparation of the bonding layer comprises the following steps: (1) dissolving the emulsifier in water, then adding acrylic acid or methacrylic acid, methyl methacrylate and butyl acrylate for pre-emulsification to obtain an emulsion; (2) heating 1 / 4-1 / 3 of the emulsion to 65-75℃, then adding 1 / 4-1 / 3 of the initiator, and reacting until the solution is transparent; (3) heating the solution obtained in step (2) to 85-100℃, then adding the remaining emulsion dropwise into the reaction system, after the dropwise addition is completed, adding the remaining initiator, and adjusting the pH value to neutral to obtain the liquid bonding layer material; The preparation process of the falling-off layer comprises the following steps: (a) adding the water-soluble polysaccharide, calcium chloride and colloid into water for swelling for 1-2h, then heating to 35-50℃, and standing for 6-12h to obtain a gel solution; (b) dissolving the epoxy resin in an organic solvent, then adding styrene and N-hydroxymethyl acrylamide, and uniformly mixing to prepare an epoxy resin solution for standby; (c) preparing the bonding layer by coating the liquid bonding layer material prepared in step (3), and at the same time, rolling a groove along the length direction of the center of the bonding layer, and coating the epoxy resin solution prepared in step (b) in the groove, and keeping the temperature at 85-100℃ for 2-4h; (d) cooling to 40-50℃, then coating the gel solution and spreading the gel solution to fill the entire groove.

6. The method for preparing a water-washable, automatically peelable self-adhesive label according to claim 5, characterized in that: The organic solvent comprises one of n-butanol, ethanol and acetone.

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