TWI862907B - Environmentally friendly non-wax water-resistant coating preparation method and paper product using the coating - Google Patents

Abstract

The present invention discloses a method for preparing an environmentally friendly non-wax water-resistant coating, which includes mixing an acrylic resin, a thermosetting polyurethane resin and a polyethylene emulsion to form a blend, adding a bonding agent to bond and seal the -OH functional groups in the blend, and then adding an aqueous solution to adjust the viscosity as needed. The environmentally friendly non-wax water-resistant coating prepared by the above method can be used on the surface of paper to improve water resistance.

Description

Environmentally friendly non-wax water-resistant coating preparation method and paper products using the coating

The present invention relates to the technical field related to coating materials, and in particular to a method for preparing an environmentally friendly non-wax water-resistant coating and a paper product using the coating.

In the previous technology, the method of making water-resistant cartons mostly used melted petroleum wax to coat the paper. After coating, the pores on the surface of the paper were covered and filled with petroleum wax. The physical barrier method and the chemical properties of oil and water being immiscible prevented water from penetrating into the paper, making the surface of the carton made of the paper protective against water, thus achieving the water-resistant requirement.

However, petroleum wax needs to be dissolved at high temperature in a heating machine before it can be applied to paper. Although it has good water resistance, petroleum wax solidifies when it is cooled and easily adheres to equipment and machines, so it needs to be shut down for cleaning and maintenance regularly, which is often criticized by the industry.

Furthermore, cartons with petroleum wax on the surface cannot be directly recycled after disposal (additional treatment is required), and there are environmental issues such as difficulty in decomposition when discarded.

In addition, when paper mills recycle cartons as raw materials, if there is petroleum wax left on the surface, it will produce stains during the papermaking process, resulting in negative effects such as chemical costs, heat dispersion costs, and reduced paper strength. In addition, the wastewater generated during the production process of paper mills will also cause problems such as difficulty in wastewater treatment.

To this end, some experts have proposed improvement plans, such as Taiwan's patent No. M406586, which uses polymer plastic film or metal foil (aluminum foil, etc.) to form a composite material by laminating or bonding it on paper. The polymer plastic film used for laminating includes plastic raw materials such as polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, and polybutylene terephthalate. This type of composite material can provide oil-proof paper with high water resistance and high gas resistance.

However, during the carton manufacturing process, the composite material components (plastic raw materials) will release toxic substances such as plasticizers during the high-temperature drying process. In addition, during the high-temperature drying process, the composite material (plastic raw materials) will adhere to the transfer auxiliary, resulting in an unstable process and quality deviation. In addition, the waste of water-resistant cartons made of laminated composite materials cannot be recycled as ordinary paper after use. It must undergo special treatment, such as high temperature and adding alkaline solution to separate the plastic film from the paper material, which invisibly increases the use of energy and chemicals, making recycling difficult and causing a burden on the environment.

The purpose of the present invention is to provide a method for preparing an environmentally friendly non-wax water-resistant coating and a paper product using the coating to overcome the deficiencies of the previous technology.

According to the above purpose of the present invention, the present invention proposes a method for preparing an environmentally friendly non-wax water-resistant coating, which includes taking an acrylic resin, a thermosetting polyurethane resin and a polyethylene emulsion to mix to form a blend, adding a bonding agent to bond and seal the -OH functional groups in the blend, and then adding an aqueous solution to adjust the viscosity according to demand. An environmentally friendly non-wax water-resistant coating is prepared by the above method.

According to the above purpose of the present invention, the present invention proposes an environmentally friendly non-wax water-resistant coating paper product, wherein the environmentally friendly non-wax water-resistant coating prepared by the above method is applied to the surface of the paper material in conjunction with a coating machine to produce a waterproof paper material product.

S1~S4: Steps

[Figure 1] is a schematic diagram of the preparation method of the environmentally friendly non-wax water-resistant coating of the present invention.

Please refer to the relevant figures below to further explain the preparation method of the environmentally friendly non-wax water-resistant coating of the present invention and the paper product embodiment using the coating. The various objects in the embodiments are depicted according to the proportions, sizes, deformation amounts or displacement amounts applicable to the description, rather than the proportions of the actual components, which should be explained first. And the same and symmetrically arranged components in the remaining embodiments are all represented by the same numbers. In addition, the directional terms such as "front, back, left, right, top, bottom, inside, outside" in the description of each embodiment listed below are expressed according to the specified viewing direction and cannot be used as an interpretation of the limitation of the present invention.

Please refer to Figure 1 for the preparation method of the environmentally friendly non-wax water-resistant coating of the present invention, which includes:

S1. Take 30~60 wt% of acrylic resin, 20~35 wt% of thermosetting polyurethane resin and 20~35 wt% of polyethylene emulsion, mix to form a blend, the total weight % of the above blend is 100.

The above blend is mixed at 600-800 rpm for 10-20 minutes and then left to stand for 30-50 minutes until the air bubbles in the blend are removed before use.

During implementation, the acrylic resin is selected from an emulsion formed by polymerization of acrylic acid derivative monomers. The thermosetting polyurethane resin is selected from an emulsion formed by polymerization of polyurethane and polyurethane derivative monomers. The polyethylene solution is selected from an emulsion formed by polymerization of polyethylene solution and polyethylene solution derivative monomers.

S2. Take 1~20% of the total weight of the blend and add the bonding agent into the blend to bond and seal the -OH functional groups of the blend to form a semi-finished coating product.

Stir the above blend evenly at 200-400 rpm, and slowly add the binder during stirring. After completion, stir evenly at 300-600 rpm for 30-40 minutes to allow the binder to bind and seal the -OH functional groups in the blend to form a semi-finished coating.

During implementation, the bonding agent is selected from one or a combination of siloxane compounds (Rx-O-Si-O-Ry)n and alkenyl succinic anhydrides. The siloxane compound (Rx-O-Si-O-Ry)n is preferably an emulsion obtained by polymerizing tetraethoxysilane and tetraethoxysilane derivative monomers.

S3. Stir the semi-finished coating evenly at 100-200 rpm for 30-40 minutes, and then let it stand for 4-6 hours to remove air bubbles before use.

S4. Add water as a solvent to the semi-finished coating and adjust the viscosity to the preset value to form a finished coating.

During implementation, the finished coating is provided for coating equipment. Different coating equipment will have working viscosity requirements, so the viscosity can be adjusted to match different coating equipment.

Therefore, the above is a preferred embodiment of the method for preparing an environmentally friendly non-wax water-resistant coating provided by the present invention, and the products produced by applying the environmentally friendly non-wax water-resistant coating are as follows:

The finished coating produced by the above-mentioned environmentally friendly non-wax water-resistant coating preparation method is put into a coating device for coating a preset end surface of a paper material, and the coating amount is preferably 3.0~9.0g/m2.

The above-mentioned coating equipment may be an on-board coating machine, an off-board coating machine or any known coating equipment.

During implementation, the main raw material of the paper material is selected from pulp composed of coniferous tree fibers, broad-leaved tree fibers, and/or other fibers that can be used for papermaking.

In addition, the coated paper can be used in conjunction with the corrugated board manufacturing process to form a multi-layer laminate (three-layer laminate or five-layer laminate) to form a paperboard, and the coated paper can be placed on the outer side of the paperboard. The paperboard can also be further made into paper products of different shapes such as cartons.

The above description is only the preferred implementation of the present invention, which is intended to clarify the features of the present invention, and is not intended to limit the scope of the embodiments of the present invention. Equal changes made by ordinary technicians in the technical field based on the present invention, as well as changes familiar to technicians in the technical field, should still fall within the scope of the present invention.

S1~S4: Steps

Claims (9)

A method for preparing an environmentally friendly non-wax water-resistant coating comprises: (a) taking 30-60 wt% of an acrylic resin, 20-35 wt% of a thermosetting polyurethane resin, and 20-35 wt% of a polyethylene emulsion, and mixing them to form a blend, wherein the total weight of the blend is 100; (b) taking 1-20 wt% of a binder based on the total weight of the blend, and adding the binder to the blend. (c) stirring the semi-finished coating product and then leaving it to stand for air bubbles to be defoamed; and (d) adding a water solvent into the semi-finished coating product and adjusting its viscosity to form a finished coating product. The method for preparing an environmentally friendly non-wax water-resistant coating as described in claim 1, wherein the blend in step (a) is uniformly stirred at 600-800 rpm for 10-20 minutes and then left to stand for 30-50 minutes. The method for preparing an environmentally friendly non-wax water-resistant coating as described in claim 1, wherein in step (b), the blend is uniformly stirred at a rotation speed of 200-400 rpm, and the binder is slowly added during the process. The method for preparing an environmentally friendly non-wax water-resistant coating as described in claim 1, wherein in step (c), the semi-finished coating is uniformly stirred at a rotation speed of 300-600 rpm for 30-40 minutes. The method for preparing an environmentally friendly non-wax water-resistant coating as described in claim 1, wherein the acrylic resin is selected from an emulsion formed by polymerizing an acrylic acid derivative monomer; the thermosetting polyurethane resin is selected from an emulsion formed by polymerizing a polyurethane and a polyurethane derivative monomer; and the polyethylene solution is selected from an emulsion formed by polymerizing a polyethylene solution and a polyethylene solution derivative monomer. As described in claim 1, the preparation method of environmentally friendly non-wax water-resistant coating, wherein the siloxane compound (Rx-O-Si-O-Ry)n is an emulsion polymerized from tetraethoxysilane and tetraethoxysilane derivative monomers. A paper product with an environmentally friendly non-wax water-resistant coating, in combination with the method for preparing the environmentally friendly non-wax water-resistant coating as described in any one of claims 1 to 6, comprises a paper material, and the finished coating applied to a preset end surface of the paper material. The environmentally friendly non-wax water-resistant coated paper product as described in claim 7, wherein the paper material is selected from pulp composed of coniferous tree fibers, broad-leaved tree fibers, and/or other fibers that can be used for papermaking. The environmentally friendly non-wax water-resistant coating paper product as described in claim 7, wherein the paper material can be made into a laminated paperboard in conjunction with the corrugated paperboard manufacturing process.

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