阅读说明：本技术 一种淀粉胶粘剂及其制备方法 (Starch adhesive and preparation method thereof ) 是由 刘亦武 谭井华 张祥 贺盼 于 2019-12-20 设计创作，主要内容包括：本发明公开了一种淀粉胶粘剂及其制备方法,本发明使用的原料包括淀粉100~120份,多巴胺6~15份,氧化剂3~8份,氢氧化钠5~10份,植物纤维10~18份,交联剂2~6份。在制备淀粉胶粘剂过程中通过氧化和糊化提高淀粉胶的初粘性,并在淀粉胶粘剂添加多巴胺和植物纤维,利用多巴胺含有丰富的羟基和氨基基团能够与纸纤维表面基团发生反应,增强淀粉胶粘剂在湿润环境中的粘附性能,以及在多巴胺和植物纤维的共同作用下提高其粘接的稳定性。(The invention discloses a starch adhesive and a preparation method thereof, and raw materials used by the starch adhesive comprise 100-120 parts of starch, 6-15 parts of dopamine, 3-8 parts of an oxidant, 5-10 parts of sodium hydroxide, 10-18 parts of plant fiber and 2-6 parts of a cross-linking agent. The initial viscosity of the starch adhesive is improved by oxidation and gelatinization in the process of preparing the starch adhesive, dopamine and plant fibers are added into the starch adhesive, and the abundant hydroxyl and amino groups contained in the dopamine can react with the surface groups of the paper fibers, so that the adhesion performance of the starch adhesive in a humid environment is enhanced, and the adhesion stability of the starch adhesive is improved under the combined action of the dopamine and the plant fibers.)

1. The starch adhesive is characterized by comprising, by weight, 100-120 parts of starch, 6-15 parts of dopamine, 3-8 parts of an oxidant, 5-10 parts of sodium hydroxide, 10-18 parts of plant fiber and 2-6 parts of a cross-linking agent.

2. The starch adhesive according to claim 1, wherein an antibacterial agent, a preservative and a drier are further added to the starch adhesive.

3. The starch adhesive as claimed in claim 2, wherein the antibacterial agent is an alkyl quaternary phosphonium salt, the preservative is potassium sorbate, and the drier is calcium carbonate.

4. The starch adhesive as claimed in claim 2, wherein the starch adhesive comprises, by weight, 110 parts of starch, 10 parts of dopamine, 5 parts of an oxidizing agent, 8 parts of sodium hydroxide, 15 parts of plant fiber, 5 parts of a cross-linking agent, 1 part of an antibacterial agent, 1 part of a preservative and 0.5 part of a drier.

5. The starch adhesive of claim 1 or 4 wherein said starch is one or more of tapioca starch, corn starch, wheat starch and potato starch.

6. The starch adhesive according to claim 1 or 4, wherein the oxidizing agent is any one of sodium hypochlorite, hydrogen peroxide or potassium permanganate.

7. The starch adhesive according to claim 1 or 4, wherein the plant fiber is one or more of sisal fiber, reed fiber or straw fiber.

8. The starch adhesive of claim 1 wherein the cross-linking agent is one or more of borax, boric acid, ammonium zirconium carbonate.

9. A method for preparing a starch adhesive according to any one of claims 1 to 8, wherein the preparation method comprises the following steps:

s1, mixing starch and water to prepare a solution with a solid content of 30-40%, adding an oxidant, heating to 40-45 ℃, and reacting for 20-50 min to obtain oxidized starch;

s2, adding sodium hydroxide into the oxidized starch obtained in the step S1, uniformly stirring, and reacting for 20-30 min to obtain gelatinized starch;

and S3, adding dopamine, plant fiber, a cross-linking agent, an antibacterial agent, a preservative and a drier into the gelatinized starch in S2, and uniformly stirring to obtain the starch adhesive.

Technical Field

The invention relates to the technical field of adhesives, and particularly relates to a starch adhesive and a preparation method thereof.

Background

The starch adhesive is prepared from starch serving as a raw material, has good bonding performance by modifying starch slurry through oxidation, gelatinization and the like, is a natural high polymer material with low price and environmental protection, has the characteristics of no toxicity and no pollution, is a green environment-friendly adhesive, and can be applied to the bonding of wood and paper materials to replace petrochemical resource synthesized adhesive.

However, in the practical application process of the starch adhesive, the starch adhesive has the defects of slow drying speed, poor water resistance and unstable bonding performance, and particularly, when the starch adhesive is bonded with corrugated boards, the corrugated boards are affected with damp in an air-wet environment, the bonding performance of the starch adhesive is reduced, the corrugated boards are easily softened, the laminated paper is easily separated, the edge pressure strength of the corrugated boards is reduced, and the like. In the existing starch adhesive, polymer resin is mostly adopted for reinforcement, the method can effectively reinforce the viscosity of the starch adhesive, but two different systems are needed for preparation, the equipment investment and the energy consumption are increased, and the preparation process is complex.

Disclosure of Invention

The invention aims to solve the technical problems of insufficient bonding strength and stability of the existing starch adhesive and provides the starch adhesive with high bonding strength and better water resistance.

The invention also provides a preparation method of the starch adhesive.

The purpose of the invention is realized by the following technical scheme:

the starch adhesive comprises, by weight, 100-120 parts of starch, 6-15 parts of dopamine, 3-8 parts of an oxidant, 5-10 parts of sodium hydroxide, 10-18 parts of plant fibers and 2-6 parts of a cross-linking agent.

Furthermore, the starch adhesive is also added with an antibacterial agent, a preservative and a drier. The antibacterial agent is alkyl quaternary phosphonium salt, the preservative is potassium sorbate, and the drier is calcium carbonate.

Further, the raw materials of the starch adhesive and the parts by weight thereof comprise 110 parts of starch, 10 parts of dopamine, 5 parts of an oxidizing agent, 8 parts of sodium hydroxide, 15 parts of plant fiber, 5 parts of a cross-linking agent, 1 part of an antibacterial agent, 1 part of a preservative and 0.5 part of a drier.

Further, the starch is one or more of tapioca starch, corn starch, wheat starch and potato starch.

Further, the oxidant is any one of sodium hypochlorite, hydrogen peroxide or potassium permanganate.

Further, the plant fiber is one or more of sisal fiber, reed fiber or straw fiber.

Further, the cross-linking agent is one or more of borax, boric acid and ammonium zirconium carbonate.

The preparation method of the starch adhesive is provided according to the starch adhesive, and the preparation steps comprise:

s1, mixing starch and water to prepare a solution with a solid content of 30-40%, adding an oxidant, heating to 40-45 ℃, and reacting for 20-50 min to obtain oxidized starch;

s2, adding sodium hydroxide into the oxidized starch obtained in the step S1, uniformly stirring, and reacting for 20-30 min to obtain gelatinized starch;

and S3, adding dopamine, plant fiber, a cross-linking agent, an antibacterial agent, a preservative and a drier into the gelatinized starch in S2, and uniformly stirring to obtain the starch adhesive.

Compared with the prior art, the beneficial effects are:

according to the invention, the initial viscosity of the starch adhesive is improved through oxidation and gelatinization in the process of preparing the starch adhesive, dopamine is added into the starch adhesive, and the dopamine containing abundant hydroxyl and amino groups can react with the surface groups of the paper fibers, so that the adhesion performance of the starch adhesive in a humid environment is enhanced. Meanwhile, the strength and water resistance of the starch adhesive are enhanced by adding the plant fiber, and the dopamine and the plant fiber are branched under the alkaline condition, so that the bonding strength of the adhesive and paper or wood is further improved.

The invention also adds an antibacterial agent, a preservative and a drier, wherein the drier accelerates the drying speed of the starch adhesive, and the antibacterial agent and the preservative enhance the pollution of bacteria and fungi to the starch adhesive after the starch adhesive is affected with damp, and prevent the decomposition of microorganisms from reducing the strength of the adhesive. The raw materials used in the invention are green and pollution-free, and the preparation process is simple and is suitable for industrial production.

Detailed Description

The following examples are further explained and illustrated, but the present invention is not limited in any way by the specific examples. Unless otherwise indicated, the methods and equipment used in the examples are conventional in the art and all materials used are conventional commercially available materials.