阅读说明：本技术 一种稀土改性淀粉基速干胶黏剂 (Rare earth modified starch-based quick-drying adhesive ) 是由 宋立军 王胜龙 林颖 吴银财 林凤龙 于 2021-07-28 设计创作，主要内容包括：本发明公开了一种稀土改性淀粉基速干胶黏剂,由如下质量百分比的组分组成：食用级改性玉米淀粉30-38wt％,聚乙烯醇6-8wt％,环保型聚丙烯酸酯乳液18-25wt％,润湿分散剂BYK-180或BYK-290 0.2-0.3wt％,消泡剂BYK-028或BYK-093 0.2-0.4wt％,杀菌剂0.3-0.4wt％,稀土复合物1-2wt％,自来水32.3-39.7wt％。本发明与纯EVA乳液相比,干燥速度相当,粘结强度不下降,但刺激性味道更低,更环保,且成本更低。(The invention discloses a rare earth modified starch-based quick-drying adhesive which comprises the following components in percentage by mass: 30-38 wt% of edible modified corn starch, 6-8 wt% of polyvinyl alcohol, 18-25 wt% of environment-friendly polyacrylate emulsion, 0.3-0.4 wt% of wetting dispersant BYK-180 or BYK-2900.2, 0.3-0.4 wt% of defoaming agent BYK-028 or BYK-0930.2, 0.3-0.4 wt% of bactericide, 1-2 wt% of rare earth compound and 32.3-39.7 wt% of tap water. Compared with pure EVA emulsion, the invention has the advantages of equivalent drying speed, no reduction of bonding strength, lower pungent taste, more environmental protection and lower cost.)

1. A rare earth modified starch-based quick-drying adhesive is characterized in that: the composite material comprises the following components in percentage by mass: 30-38 wt% of edible modified corn starch, 6-8 wt% of polyvinyl alcohol, 18-25 wt% of environment-friendly polyacrylate emulsion, 0.3-0.4 wt% of wetting dispersant BYK-180 or BYK-2900.2, 0.3-0.4 wt% of defoaming agent BYK-028 or BYK-0930.2, 0.3-0.4 wt% of bactericide, 1-2 wt% of rare earth compound and 32.3-39.7 wt% of tap water;

the edible modified corn starch is modified corn starch with viscosity of 100-600cp, which is gelatinized by sodium hydroxide and oxidized by sodium hypochlorite; the solid content of the environment-friendly polyacrylate emulsion is 50-55 wt%, the viscosity is 8000-10000cp, and the glass transition temperature is 9-11 ℃; the rare earth compound contains cerium and lanthanum, and is composed of an organic rare earth compound and an inorganic rare earth compound.

2. The rare earth modified starch-based quick-drying adhesive of claim 1, wherein: the rare earth compound consists of cerous tartrate, cerium lanthanum carbonate and cerium fluoride.

3. The rare earth modified starch-based quick-drying adhesive of claim 2, wherein: the contents of the cerous tartrate, the lanthanum carbonate and the cerium fluoride in the rare earth composite are 15 wt%, 45 wt% and 40 wt% in sequence.

4. The rare earth modified starch-based quick-drying adhesive of claim 1, wherein: the rare earth compound consists of lanthanum chloride and cerium cinnamate.

5. The rare earth modified starch-based quick-drying adhesive of claim 4, wherein: the contents of the lanthanum chloride and the cerium cinnamate in the rare earth compound are 65 wt% and 35 wt% in sequence.

6. The rare earth modified starch-based quick-drying adhesive of claim 1, wherein: the rare earth compound consists of cerium oxide, lanthanum fluoride, cerium cinnamate and cerium tartrate.

7. The rare earth modified starch-based quick-drying adhesive of claim 6, wherein: the contents of the cerium oxide, the lanthanum fluoride, the cerium cinnamate and the cerium tartrate in the rare earth composite are 20 wt%, 40 wt%, 20 wt% and 20 wt% in sequence.

8. The rare earth modified starch-based quick-drying adhesive of any one of claims 1 to 7, wherein: the polyvinyl alcohol types include 1788, 1799, 2488, 2499, 2688 and 2699.

9. The rare earth modified starch-based quick-drying adhesive of claim 8, wherein: the polyvinyl alcohol is 2499 or 2699 in model.

10. The rare earth modified starch-based quick-drying adhesive of any one of claims 1 to 7, wherein: the bactericide is low-toxicity isothiazolinone.

Technical Field

The invention belongs to the technical field of aqueous adhesive materials, and particularly relates to a rare earth modified starch-based quick-drying adhesive.

Background

Starch is a biomass material which is wide in source, edible, renewable, degradable, cheap and environment-friendly, and is widely used in the adhesive industry. The molecular chain of the starch has a large number of hydroxyl functional groups, and the strong hydrophilic functional groups can generate interaction to form a large number of hydrogen bonds, so that the starch has certain adhesive force and film-forming property. But meanwhile, the intermolecular force formed by the hydroxyl and water is strong, and the drying speed is slow due to slow water volatilization, so that the requirement of modern production line operation of paper products cannot be met. Therefore, the improvement of the drying speed of the starch-based adhesive becomes a key problem to be solved urgently in the industry.

CN 103265909A discloses a high-solid content quick-drying modified starch lap adhesive, which is prepared by adding nano sepiolite powder into starch adhesive with high solid content and good fluidity, and the initial adhesion rate of more than 98 percent needs 25 s.

The technical scheme disclosed in CN 109971391 a is to further modify corn starch with epichlorohydrin and urea-formaldehyde resin, to make kaolin break its silicon-oxygen bond and aluminum-oxygen bond under the action of alkali solution, to form a series of silicon-oxygen tetrahedron and aluminum-oxygen tetrahedron units in oligomeric state, which gradually dehydrate and repolymerize with the reaction, to form network silicon-aluminum-oxygen compound-metakaolin, and to add alkaline metakaolin powder containing silicon-oxygen bond and aluminum-oxygen bond into the raw material, to make it cross-link with the groups in corn starch under the action of anhydrous ethanol, so as to enhance the viscosity of the system, further improve the adhesive strength of the quick-drying adhesive, but the curing time is still not ideal.

CN 106947410A discloses a low-temperature quick-drying starch adhesive for corrugated board production lines and a preparation method thereof, wherein the adhesive comprises the following raw materials in parts by weight: 100 parts of corn starch, 400 parts of water, 3-3.5 parts of sodium hypobromite, 6-8 parts of sodium alginate gel, 0.3-0.5 part of nickel sulfate solution, 6-8 parts of sodium hydroxide solution, 1.1-1.3 parts of tributyl phosphate and 3-5 parts of drier. The curing time of the adhesive needs to be 5 minutes at the shortest.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a rare earth modified starch-based quick-drying adhesive.

The technical scheme of the invention is as follows:

the rare earth modified starch-based quick-drying adhesive comprises the following components in percentage by mass: 30-38 wt% of edible modified corn starch, 6-8 wt% of polyvinyl alcohol, 18-25 wt% of environment-friendly polyacrylate emulsion, 0.3-0.4 wt% of wetting dispersant BYK-180 or BYK-2900.2, 0.3-0.4 wt% of defoaming agent BYK-028 or BYK-0930.2, 0.3-0.4 wt% of bactericide, 1-2 wt% of rare earth compound and 32.3-39.7 wt% of tap water;

the edible modified corn starch is modified corn starch with viscosity of 100-600cp, which is gelatinized by sodium hydroxide and oxidized by sodium hypochlorite; the solid content of the environment-friendly polyacrylate emulsion is 50-55 wt%, the viscosity is 8000-10000cp, and the glass transition temperature is 9-11 ℃; the rare earth compound contains cerium and lanthanum, and is composed of at least two of cerous tartrate, cerous lanthanum carbonate, cerous cinnamate, cerium fluoride, cerium oxide, lanthanum chloride and lanthanum fluoride.

In a preferred embodiment of the present invention, the rare earth complex consists of cerium tartrate, lanthanum cerium carbonate and cerium fluoride.

Further preferably, the contents of the cerium tartrate, the cerium lanthanum carbonate and the cerium fluoride in the rare earth composite are 15 wt%, 45 wt% and 40 wt% in this order.

In a preferred embodiment of the present invention, the rare earth complex consists of lanthanum chloride and cerium cinnamate.

Further preferably, the contents of the lanthanum chloride and the cerium cinnamate in the rare earth composite are 65 wt% and 35 wt% in sequence.

In a preferred embodiment of the present invention, the rare earth complex consists of cerium oxide, lanthanum fluoride, cerium cinnamate and cerium tartrate.

Further preferably, the contents of the cerium oxide, the lanthanum fluoride, the cerium cinnamate and the cerium tartrate in the rare earth composite are 20 wt%, 40 wt%, 20 wt% and 20 wt% in sequence.

In a preferred embodiment of the present invention, the polyvinyl alcohol is in the types including 1788, 1799, 2488, 2499, 2688 and 2699.

More preferably, the polyvinyl alcohol is 2499 or 2699 in type.

In a preferred embodiment of the invention, the biocide is a low toxicity isothiazolinone.

The invention has the beneficial effects that:

1. compared with pure EVA emulsion, the invention has the advantages of equivalent drying speed, no reduction of bonding strength, lower pungent taste, more environmental protection and lower cost.

2. Tap water, edible modified corn starch, polyvinyl alcohol and a small amount of polyacrylate emulsion are selected as main components, other components are used as functional auxiliaries, and the rare earth compound mainly plays a role in accelerating drying; has the following functions: (1) the rare earth compound is formed by organic and inorganic rare earth compounds, and the addition of the organic rare earth compounds improves the dispersion uniformity of the inorganic rare earth compounds in organic polymers and improves the rare earth drying effect; (2) the rare earth element outer layer hollow rail is easy to form coordination with oxygen elements in water, starch, polyvinyl alcohol and polyacrylate, can bridge modified corn starch, polyvinyl alcohol and polyacrylate, improves the rapid film forming efficiency and the initial adhesion rate, and in addition, the rare earth element can also generate coordination with hydroxyl in paper fibers, so that the initial adhesion rate of the adhesive is improved; (3) the coordination number of the rare earth element and water can reach 8-12, after the adhesive is applied with glue, under the same condition, the adhesive containing the rare earth element does not need to volatilize a large amount of water to realize rapid bonding, and the initial bonding time can be shortened; by multiple actions of rare earth elements, the gluing can be carried out for 11s, the initial adhesion rate of paper reaches more than 98%, the drying time is greatly shortened, and the bonding efficiency is higher.

3. The polyacrylate emulsion is prepared by copolymerizing monomers such as methyl acrylate, butyl acrylate, vinyl acetate, acrylic acid, styrene, methyl methacrylate, ethyl methacrylate and the like, and the solid content and the storage stability of the edible modified corn starch are mainly improved.

4. The defoaming agent provided by the invention defoams the glue solution, and improves the appearance of the product.

5. The wetting dispersant of the invention can play a role in wetting substrates such as paper and the like.

6. The bactericide in the invention is low-toxicity isothiazolinone, and plays a role in preventing the quality reduction caused by mildew in the starch glue storage process.

Detailed Description

The technical solution of the present invention is further illustrated and described by the following detailed description.

The polyacrylate emulsion in the following examples and comparative examples is a commercially available Hanhua RW-116 environment-friendly acrylate emulsion, which is prepared by copolymerizing monomers such as methyl acrylate, butyl acrylate, vinyl acetate, acrylic acid, styrene, methyl methacrylate, ethyl methacrylate and the like, and has a solid content of 50%, a viscosity of 8000-10000cp and a glass transition temperature of 10 ℃.

Example 1

(1) Preparing food-grade modified corn starch: pouring tap water and corn starch into an enamel reaction kettle, heating to 50 ℃, adjusting the pH to 10 by using a 10% sodium hydroxide solution, and gelatinizing for 20 min; then, adding sodium hypochlorite liquid with the starch content of 10%, oxidizing for 1h, and ensuring the pH value to be 9 to obtain a solution with the viscosity of 600 cp; and cooling, discharging and drying after the reaction is finished.

(2) Preparing a polyvinyl alcohol solution: pouring tap water and polyvinyl alcohol 2499 into an enamel reaction kettle, heating to 90 ℃, preserving heat, stirring for 2h, cooling and discharging.

(3) Adding the edible modified corn starch obtained in the step (1) into the polyvinyl alcohol solution obtained in the step (2), stirring, heating to 50 ℃, and stirring until the viscosity meets the requirement;

(4) adding the polyacrylate emulsion into the material obtained in the step (3) according to the mass ratio, and stirring at the rotating speed of 800r/min for 10 min; adding defoaming agent, bactericide and dispersant, and continuing stirring at the same speed for 10 min; and finally, adding a rare earth compound consisting of 15 wt% of cerous tartrate, 45 wt% of lanthanum cerium carbonate and 40 wt% of cerium fluoride, stirring at the rotating speed of 1000r/min for 10min, cooling, discharging and packaging.

The following table 1 shows the composition ratio of the rare earth modified starch-based quick-drying adhesive prepared in this example:

table 1 ingredient ratio

Serial number	Name (R)	Mass percent/%)
			1	Food grade modified corn starch	33
2	Polyvinyl alcohol 2499	8
			3	Polyacrylate emulsions	25
4	Dispersant BYK-290	0.2
			5	Defoaming agent BYK-028	0.2
6	Low-toxicity isothiazolinone	0.3
			7	Rare earth composite	1
8	Tap water	32.3

The adhesion of the rare earth modified starch-based quick-drying adhesive prepared in this example to kraft paper is excellent, and the following table 2 shows the effect comparison between this example and pure polyvinyl acetate emulsion (VAE).

Table 2 comparison of the bonding effect of kraft paper

Type of packing	Temperature/. degree.C	Humidity/%)	Initial tack 98%/second
				The invention	25	75	16
Pure VAE emulsion	25	75	14

The adhesion of the rare earth modified starch-based quick-drying adhesive prepared in this example to plastic products and the effect of pure polyvinyl acetate emulsion (VAE) are shown in table 3 below:

TABLE 3 comparison of the bonding effects on the plastic articles

Type of packing	Temperature/. degree.C	Humidity/%)	Initial tack 98%/second
				The invention	25	75	26
Pure VAE emulsion	25	75	27

Example 2

(1) Preparing food-grade modified corn starch: pouring tap water and corn starch into an enamel reaction kettle, heating to 60 ℃, adjusting the pH to 11 by using 10% sodium hydroxide solution, and gelatinizing for 20 min; then, adding sodium hypochlorite liquid with the starch content being 20%, oxidizing for 2h, and ensuring the pH value to be 9.5 to obtain a solution with the viscosity of 400 cp; and cooling, discharging and drying after the reaction is finished.

(2) Preparing a polyvinyl alcohol solution: pouring tap water and polyvinyl alcohol 2499 into an enamel reaction kettle, heating to 93 ℃, preserving heat, stirring for 1.5h, cooling and discharging.

(3) Adding the edible modified corn starch obtained in the step (1) into the polyvinyl alcohol solution obtained in the step (2), stirring, heating to 70 ℃, and stirring until the viscosity meets the requirement;

(4) adding the polyacrylate emulsion into the material obtained in the step (3) according to the mass ratio, and stirring at the rotating speed of 800r/min for 20 min; adding defoaming agent, bactericide and dispersant, and stirring at the same speed for 20 min; and finally, adding a rare earth compound consisting of 65 wt% of lanthanum chloride and 35 wt% of cerium cinnamate, stirring at the rotating speed of 1000r/min for 20min, cooling, discharging and packaging.

The following table 4 shows the composition ratio of the rare earth modified starch-based quick-drying adhesive prepared in this example:

TABLE 4 composition ratio of each component

Serial number	Name (R)	Mass percent/%)
			1	Food grade modified corn starch	30
2	Polyvinyl alcohol 2499	7
			3	Polyacrylate emulsions	21
4	Dispersant BYK-290	0.2
			5	Defoaming agent BYK-028	0.3
6	Low-toxicity isothiazolinone	0.3
			7	Rare earth composite	1.5
8	Tap water	39.7

The adhesion of the rare earth modified starch-based quick-drying adhesive prepared in this example to kraft paper is excellent, and the following table 5 shows the effect comparison between this example and pure polyvinyl acetate emulsion (VAE).

Table 5 comparison of kraft paper bonding effect

Type of packing	Temperature/. degree.C	Humidity/%)	Initial tack 98%/second
				This example	20	90	14
Pure VAE emulsion	20	90	15

The adhesion of the rare earth modified starch-based quick-drying adhesive prepared in this example to plastic products and the effect of pure polyvinyl acetate emulsion (VAE) are shown in table 6 below:

TABLE 6 comparison of the bonding effects on the plastic articles

Type of packing	Temperature/. degree.C	Humidity/%)	Initial tack 98%/second
				This example	20	90	28
Pure VAE emulsion	20	90	29

Example 3

(1) Preparing food-grade modified corn starch: pouring tap water and corn starch into an enamel reaction kettle, heating to 70 ℃, adjusting the pH to 12 by using 10% sodium hydroxide solution, and gelatinizing for 40 min; then, adding sodium hypochlorite liquid with the starch content of 25%, oxidizing for 3h, and ensuring the pH value to be 10 to obtain a solution with the viscosity of 400 cp; and cooling, discharging and drying after the reaction is finished.

(2) Preparing a polyvinyl alcohol solution: pouring tap water and polyvinyl alcohol 2499 into an enamel reaction kettle, heating to 95 ℃, preserving heat, stirring for 1h, cooling and discharging.

(3) Adding the edible modified corn starch obtained in the step (1) into the polyvinyl alcohol solution obtained in the step (2), stirring, heating to 70 ℃, and stirring until the viscosity meets the requirement;

(4) adding the polyacrylate emulsion into the material obtained in the step (3) according to the mass ratio, and stirring for 30min at the rotating speed of 800 r/min; adding defoaming agent, bactericide and dispersant, and stirring at the same speed for 20 min; and finally, adding a rare earth compound consisting of 20 wt% of cerium oxide, 40 wt% of lanthanum fluoride, 20 wt% of cerium cinnamate and 20 wt% of cerium tartrate, stirring for 30min at the rotating speed of 1000r/min, cooling, discharging and packaging.

The following table 7 shows the composition ratio of the rare earth modified starch-based quick-drying adhesive prepared in this example:

table 7 composition ratio of each component

Serial number	Name (R)	Mass percent/%)
			1	Food grade modified corn starch	38
2	Polyvinyl alcohol 2499	6
			3	Polyacrylate emulsions	18
4	Dispersant BYK-290	0.3
			5	Defoaming agent BYK-028	0.4
6	Low-toxicity isothiazolinone	0.4
			7	Rare earth composite	2
8	Tap water	34.9

The adhesion of the rare earth modified starch-based quick-drying adhesive prepared in this example to kraft paper is excellent, and the following table 8 shows the effect comparison between this example and pure polyvinyl acetate emulsion (VAE).

TABLE 8 comparison of the bonding effect of kraft paper

Type of packing	Temperature/. degree.C	Humidity/%)	Initial tack 98%/second
				This example	23	85	25
Pure VAE emulsion	23	85	26

The adhesion of the rare earth modified starch-based quick-drying adhesive prepared in this example to plastic products and the effect of pure polyvinyl acetate emulsion (VAE) are shown in table 9 below:

TABLE 9 comparison of the adhesion effects on plastics

Type of packing	Temperature/. degree.C	Humidity/%)	Initial tack 98%/second
				This example	20	90	28
Pure VAE emulsion	20	90	29

Comparative example 1

(1) Preparing food-grade modified corn starch: pouring tap water and corn starch into an enamel reaction kettle, heating to 60 ℃, adjusting the pH to 11 by using 10% sodium hydroxide solution, and gelatinizing for 10 min; then, adding sodium hypochlorite liquid with the starch content being 20%, oxidizing for 2h, and ensuring the pH value to be 9.5 to obtain a solution with the viscosity of 400 cp; and cooling, discharging and drying after the reaction is finished.

(2) Preparing a polyvinyl alcohol solution: pouring tap water and polyvinyl alcohol 2499 into an enamel reaction kettle, heating to 93 ℃, preserving heat, stirring for 1.5h, cooling and discharging.

(3) Adding the edible modified corn starch obtained in the step (1) into the polyvinyl alcohol solution obtained in the step (2), stirring, heating to 70 ℃, and stirring until the viscosity meets the requirement;

(4) adding the polyacrylate emulsion into the material obtained in the step (3) according to the mass ratio, and stirring at the rotating speed of 800r/min for 20 min; adding defoaming agent, bactericide and dispersant, stirring at the same speed for 20min, cooling, discharging, and packaging.

The following table 10 shows the composition ratios of the products prepared in this comparative example:

TABLE 10 proportions of the ingredients

The adhesion of the product made by this comparative example to kraft paper is shown in table 11 below, together with the effect of the rare earth modified starch based quick drying adhesive made in example 2.

TABLE 11 comparison of the bonding effect on Kraft paper

Type of packing	Temperature/. degree.C	Humidity/%)	Initial tack 98%/second
				Rare earth-doped composites	23	85	11
Non-additive rare earth compound	23	85	40

The adhesion of the product prepared in this comparative example to a plastic article and the effect of the rare earth modified starch based quick drying adhesive prepared in example 2 are shown in table 12 below:

TABLE 12 comparison of the bonding effects on the plastic articles

Type of packing	Temperature/. degree.C	Humidity/%)	Initial tack 98%/second
				Rare earth-doped composites	23	85	25
Non-additive rare earth compound	23	85	62

The above description is only a preferred embodiment of the present invention, and therefore should not be taken as limiting the scope of the invention, which is defined by the appended claims.