阅读说明：本技术 一种氧化玉米淀粉胶粘剂及其制备方法 (Oxidized corn starch adhesive and preparation method thereof ) 是由 陈力群 于 2019-11-20 设计创作，主要内容包括：本发明公开了一种氧化玉米淀粉胶粘剂及其制备方法,包括：所述氧化玉米淀粉胶粘剂的原料组成及其重量份比为：玉米淀粉8～30份、NaOH0.9～2.0份、H<Sub>2</Sub>O<Sub>2</Sub>1～3份、水60～80份、催化剂0.01～0.12份、表面活性剂0.01～0.20份、聚丙烯酰胺0.02～0.20份、交联剂0.1～2份、稀释剂0.1～1份、消泡剂0.01～0.1份、催干剂0.1～5份、防腐剂0.01～0.5份。本发明,通过对玉米淀粉进行预糊化、氧化、糊化、交联以及改性得到氧化玉米淀粉胶粘剂；制备的氧化玉米淀粉胶粘剂的机械性能好、初粘力大、黏合力强、干燥速度快、成膜性和稳定性好。(The invention discloses an oxidized corn starch adhesive and a preparation method thereof, wherein the oxidized corn starch adhesive comprises the following steps: the oxidized corn starch adhesive comprises the following raw materials in parts by weight: 8-30 parts of corn starch, 0.9-2.0 parts of NaOH0.9 and H 2 O 2 1 to 3 parts, 60 to 80 parts of water, 0.01 to 0.12 part of catalyst, 0.01 to 0.20 part of surfactant, 0.02 to 0.20 part of polyacrylamide, 0.1 to 2 parts of cross-linking agent, 0.1 to 1 part of diluent, 0.01 to 0.1 part of defoaming agent, 0.1 to 5 parts of drier, 0.01 to E0.5 part. The invention obtains the oxidized corn starch adhesive by pre-gelatinizing, oxidizing, gelatinizing, crosslinking and modifying the corn starch; the prepared oxidized corn starch adhesive has the advantages of good mechanical property, large initial adhesion, strong adhesion, high drying speed, good film forming property and good stability.)

1. An oxidized corn starch adhesive is characterized in that,

the oxidized corn starch adhesive comprises the following raw materials in parts by weight: 8-30 parts of corn starch, 0.9-2.0 parts of NaOH0.9 and H₂O₂1-3 parts of water, 60-80 parts of catalyst, 0.01-0.12 part of catalyst, 0.01-0.20 part of surfactant, 0.02-0.20 part of polyacrylamide, 0.1-2 parts of cross-linking agent, 0.1-1 part of diluent, 0.01-0.1 part of defoaming agent, 0.1-5 parts of drier and 0.01-0.5 part of preservative.

2. The oxidized corn starch adhesive according to claim 1, wherein the antifoaming agent is tributyl phosphate, higher alcohols, fatty amides, silicones, natural oils or glycerol.

3. The oxidized corn starch adhesive of claim 1, wherein the diluent is one or more of urea, thiourea and boric acid;

the cross-linking agent is borax, sodium metaborate, sodium trimetaphosphate or oxalic acid.

4. The oxidized corn starch adhesive of claim 1, wherein the surfactant is one or more of sodium fatty acid, sodium higher fatty acid, fatty alcohol polyoxyethylene ether sulfate, and sodium pyrophosphate;

the drier is one or more of polyvinyl alcohol, calcium carbonate, kaolin and sodium bentonite;

the antiseptic is sodium benzoate, acrylic acid, calcium propionate, sodium sulfite, chlorinated hydrocarbon or p-hydroxybenzoate.

5. A method of preparing the oxidized corn starch adhesive of claim 1,

the preparation method sequentially comprises the following steps:

1) weighing the raw materials according to the proportion; dividing the water into two parts, wherein one part is used for dissolving corn starch, and the other part is used for dissolving the rest other raw materials;

2) adding corn starch into a reactor, adding water, stirring until a uniform milky suspension is formed, adding a catalyst, heating, stirring for 15-40 min, and pre-gelatinizing;

3) adding H after pre-gelatinization₂O₂Dropwise adding NaOH while stirring to adjust the pH value to 8-10, heating and stirring for 1-2 h for oxidation;

4) after oxidation, adding the residual NaOH, stirring for 15-40 min, and pasting;

5) after pasting, adding a cross-linking agent, heating and stirring for cross-linking;

6) and after crosslinking, adding polyacrylamide, stirring for 5-15 min, sequentially adding a defoaming agent, a diluent, a surfactant, a drier and a preservative, continuously stirring for 20-40 min for modification, cooling and discharging to obtain the oxidized corn starch adhesive.

6. The preparation method of the oxidized corn starch adhesive according to claim 5, wherein in the step 2), the mixture is heated and stirred for 20-30 min at a temperature of 35-45 ℃ and the catalyst is ferrous sulfate.

7. The method for preparing oxidized corn starch adhesive according to claim 5, wherein in step 3), H₂O₂The mass fraction is 30%, and the heating and stirring are carried out for 1-2 h, wherein the heating temperature is 55-70 ℃.

8. The preparation method of the oxidized corn starch adhesive according to claim 5, wherein in the step 4), the mixture is heated and stirred for 25-30 min, and the gelatinization temperature is 55-65 ℃.

9. The preparation method of the oxidized corn starch adhesive according to claim 5, wherein in the step 5), the mixture is heated and stirred for 20-40 min, and the crosslinking temperature is 55-65 ℃.

10. The method for preparing the oxidized corn starch adhesive according to claim 5, wherein the defoaming agent is tributyl phosphate, higher alcohol, aliphatic amide, polysiloxane, natural oil or glycerol;

the cross-linking agent is borax, sodium metaborate, sodium trimetaphosphate or oxalic acid;

the diluent is one or more of urea, thiourea and boric acid;

the surfactant is one or more of sodium fatty acid, sodium higher fatty acid, sodium alkyl sulfate, sodium alkyl benzene sulfonate, fatty alcohol-polyoxyethylene ether sulfate and sodium pyrophosphate;

the drier is one or more of polyvinyl alcohol, calcium chloride, calcium carbonate, kaolin and sodium bentonite;

the antiseptic is sodium benzoate, acrylic acid, calcium propionate, sodium sulfite, chlorinated hydrocarbon or p-hydroxybenzoate.

Technical Field

The invention belongs to the technical field of application type fine chemical engineering, relates to the field of starch adhesives, and particularly relates to an oxidized corn starch adhesive and a preparation method thereof.

Background

The corn starch is a green and environment-friendly renewable natural product, is cheap and easy to obtain, and has good degradability. The corn starch adhesive is widely applied to the industries of paper making, building, printing and binding, medical treatment, carton packaging and bonding and the like. However, the conventional corn starch adhesive has the defects of unstable quality, low bonding force, poor fluidity, low drying speed and the like. The traditional method has the advantages of small expansion degree of starch granules, incomplete oxidation, relatively small number of generated carboxyl groups and low binding power. Probably because the gelatinized and expanded starch molecules are rearranged and combined to form a substance similar to starch macromolecules, the aging and gelatinization phenomena occur, and the stability is poor. In the cross-linking process of the traditional starch adhesive, hydroxyl in oxidized starch and empty orbitals of electrons at the outermost layer of boron atoms in a cross-linking agent form a network structure ligand, so that the starch adhesive becomes thick and poor in fluidity. The solid content is relatively low, so that the starch glue has poor water loss rate and low drying speed.

In conclusion, the research and development of the novel oxidized starch paste adhesive with good mechanical property, strong viscosity, quick drying and stability has wide significance.

Disclosure of Invention

The invention aims to provide an oxidized corn starch adhesive and a preparation method thereof, so as to solve one or more technical problems. The invention obtains the oxidized corn starch adhesive by pre-gelatinizing, oxidizing, gelatinizing, crosslinking and modifying the corn starch; the prepared oxidized corn starch adhesive has the advantages of good mechanical property, large initial adhesion, strong adhesion, high drying speed, good film forming property and good stability.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention relates to an oxidized corn starch adhesive, which comprises the following raw materials in parts by weight: 8-30 parts of corn starch, 0.9-2.0 parts of NaOH0.9 and H₂O₂1-3 parts of water, 60-80 parts of catalyst, 0.01-0.12 part of catalyst, 0.01-0.20 part of surfactant, 0.02-0.20 part of polyacrylamide, 0.1-2 parts of cross-linking agent, 0.1-1 part of diluent, 0.01-0.1 part of defoaming agent, 0.1-5 parts of drier and 0.01-0.5 part of preservative.

The invention further improves that the defoaming agent is tributyl phosphate, higher alcohol, aliphatic amide, polysiloxane, natural grease or glycerol.

In a further improvement of the invention, the diluent is one or more of urea, thiourea and boric acid; the cross-linking agent is borax, sodium metaborate, sodium trimetaphosphate or oxalic acid.

The invention is further improved in that the surfactant is one or more of sodium fatty acid, sodium higher fatty acid, fatty alcohol-polyoxyethylene ether sulfate and sodium pyrophosphate; the drier is one or more of polyvinyl alcohol, calcium carbonate, kaolin and sodium bentonite; the antiseptic is sodium benzoate, acrylic acid, calcium propionate, sodium sulfite, chlorinated hydrocarbon or p-hydroxybenzoate.

The preparation method of the oxidized corn starch adhesive sequentially comprises the following steps of:

1) weighing the raw materials according to the proportion; dividing the water into two parts, wherein one part is used for dissolving corn starch, and the other part is used for dissolving the rest other raw materials;

2) adding corn starch into a reactor, adding water, stirring until a uniform milky suspension is formed, adding a catalyst, heating, stirring for 15-40 min, and pre-gelatinizing;

3) adding H after pre-gelatinization₂O₂Dropwise adding NaOH while stirring to adjust the pH value to 8-10, heating and stirring for 1-2 h for oxidation;

4) after oxidation, adding the residual NaOH, stirring for 15-40 min, and pasting;

5) after pasting, adding a cross-linking agent, heating and stirring for cross-linking;

6) and after crosslinking, adding polyacrylamide, stirring for 5-15 min, sequentially adding a defoaming agent, a diluent, a surfactant, a drier and a preservative, continuously stirring for 20-40 min for modification, cooling and discharging to obtain the oxidized corn starch adhesive.

The further improvement of the invention is that in the step 2), the mixture is heated and stirred for 20-30 min, the heating temperature is 35-45 ℃, and the catalyst is ferrous sulfate.

In a further development of the invention, in step 3), H₂O₂30 percent by mass, and is heated and stirred for 1-2 hours at a heating temperature of 55 &70℃。

The further improvement of the invention is that in the step 4), the heating and stirring are carried out for 25-30 min, and the gelatinization temperature is 55-65 ℃.

The further improvement of the invention is that in the step 5), the mixture is heated and stirred for 20-40 min, and the crosslinking temperature is 55-65 ℃.

The invention is further improved in that the defoaming agent is tributyl phosphate, higher alcohol, aliphatic amide, polysiloxane, natural grease or glycerol; the cross-linking agent is borax, sodium metaborate, sodium trimetaphosphate or oxalic acid; the diluent is one or more of urea, thiourea and boric acid; the surfactant is one or more of sodium fatty acid, sodium higher fatty acid, sodium alkyl sulfate, sodium alkyl benzene sulfonate, fatty alcohol-polyoxyethylene ether sulfate and sodium pyrophosphate; the drier is one or more of polyvinyl alcohol, calcium chloride, calcium carbonate, kaolin and sodium bentonite; the antiseptic is sodium benzoate, acrylic acid, calcium propionate, sodium sulfite, chlorinated hydrocarbon or p-hydroxybenzoate.

Compared with the prior art, the invention has the following beneficial effects:

the oxidized corn starch adhesive has the advantages of large initial adhesion, strong adhesion, high drying speed and good stability.

The preparation method can prepare the oxidized corn starch adhesive, and the oxidized corn starch adhesive has the advantages of large initial adhesion, strong adhesion, high drying speed and good stability; specifically, the catalyst is adopted and heated and stirred for 15-40 min, so that the swelling degree of the starch cluster is better, and the oxidation probability is increased; adopts green environment-friendly H₂O₂Heating and stirring for 1-2 h as an oxidant, wherein the oxidation degree of the corn starch is better, and the content of carboxyl is the largest, so that the adhesive force of the oxidized corn starch glue is increased; heating and stirring for 15-40 min by using NaOH as a pasting agent, wherein the pasting effect of the oxidized corn is good, and the solubility and the fluidity of the oxidized corn are good; the crosslinking reaction is carried out by adding the crosslinking agent, heating and stirring, the crosslinking degree is better, and the adhesive force is large; the addition of surfactant and drier can effectively prevent starch from being largeThe agglomeration of molecules can prevent the aging of the corn starch glue and enhance the stability of the adhesive; the flexibility and the initial adhesion of the corn starch glue can be enhanced by adding polyacrylamide; the toughness and the fluidity of the starch glue can be enhanced by adding the diluent; the drying speed can be improved by adding the drier, and the solid content is increased.

Further, in the invention, the mixture is heated and stirred for 20-30 min, the heating temperature is 35-45 ℃, and the catalyst is ferrous sulfate; heating and stirring the mixture at 35-45 ℃ for 15-30 min by taking ferrous sulfate as a catalyst, wherein the expansion degree of the starch cluster is optimal, so that the oxidation probability is increased; if the pre-gelatinization time is too short, the degree of swelling of the starch dough is reduced; the expansion of the starch cluster destroys the hydroxyl association in the starch macromolecules to a certain extent, so that the oxidation probability is increased, after pre-gelatinization, the next oxidation reaction is relatively thorough, and the number of generated carboxyl groups is increased.

Further, H₂O₂The mass fraction is 30%, and the heating and stirring are carried out for 1-2 h, wherein the heating temperature is 55-70 ℃. The invention adopts green environment-friendly H₂O₂Heating and stirring the mixture as an oxidant at the temperature of 55-70 ℃ for 1-2 h, wherein the oxidation degree of the corn starch is optimal, and the carboxyl content is maximum so that the adhesion of oxidized corn starch glue is increased; the oxidation time is too short, the oxidation is not thorough, and the number of generated carboxyl is insufficient; meanwhile, the dosage of the oxidant cannot be too much, the number of generated carboxyl groups is increased along with the increase of the reaction time, and the number of the carboxyl groups is not increased any more after a certain reaction time. Excessive oxidant easily causes excessive oxidation, so that macromolecular chains of starch are broken, hydroxymethyl is changed into aldehyde groups, intermolecular hydrogen bonding is reduced, and viscosity is reduced. The reaction temperature is too low, the catalyst and the oxidant cannot well permeate into the starch granules, the reaction speed is slow, the oxidation degree is not enough, and the carboxyl content is low; at too high a temperature, the reaction rate increases, but the starch granules become gelatinized and the penetration of the oxidizing agent into the starch granules decreases, while at too high a temperature H increases₂O₂The decomposition rate of (a) results in a decrease in the degree of oxidation.

Further, the invention is heated and stirred for 25-30 min, and the gelatinization temperature is 55-65 ℃. Heating and stirring the oxidized corn for 15-30 min at 55-65 ℃ by using NaOH as a pasting agent, wherein the pasting effect of the oxidized corn is optimal, the reaction time is short due to good solubility and fluidity, hydrogen bonds among starch molecules are not opened, and carboxyl groups still have no hydrophilicity. The gelatinization is not complete due to too low temperature, the initial viscosity is reduced, the temperature is too high, the quality guarantee period is shortened, and the gelation phenomenon is easy to occur. NaOH is added to form sodium salt with carboxyl in oxidized starch, so that the fluidity and the solubility of the starch glue are improved, the excessive NaOH causes the viscosity of the starch glue to be reduced, the generated foam is increased, and the corrosivity is increased.

Further, heating and stirring are carried out for 20-40 min, and the crosslinking temperature is 55-65 ℃. According to the invention, the crosslinking reaction is carried out by adding the crosslinking agent, heating and stirring at 55-65 ℃ for 20-40 min, so that the crosslinking degree is optimal and the adhesive force is high; insufficient crosslinking time, insufficient crosslinking degree, reduced initial adhesion, too long crosslinking time, reduced adhesion and reduced transparency. The starch adhesive has the advantages that the crosslinking agent is insufficient, the crosslinking degree is insufficient, the self-polymerization is caused due to the hydrogen bond action among starch molecules, the retrogradation phenomenon is caused, the initial viscosity is poor, the crosslinking agent is excessive, the excessive crosslinking is caused, large-mesh-structure macromolecular substances can be formed with the starch, the fluidity of the corn starch adhesive is poor, and the gelatinization is easy to form.

Furthermore, the surface active agent and the polyvinyl alcohol are added, so that the agglomeration of starch macromolecules can be effectively prevented, the corn starch glue can be prevented from aging, and the stability of the adhesive can be enhanced; the flexibility and the initial adhesion of the corn starch glue can be enhanced by adding polyacrylamide; the toughness and the fluidity of the starch glue can be enhanced by adding the diluent; the drying speed can be improved by adding the drier, and the solid content is increased.

Detailed Description

In order to make the purpose, technical effect and technical solution of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention is clearly and completely described below; it is to be understood that the described embodiments are only some of the embodiments of the present invention. Other embodiments, which can be derived by one of ordinary skill in the art from the disclosed embodiments without inventive faculty, are intended to be within the scope of the invention.

The oxidized corn starch adhesive provided by the embodiment of the invention comprises the following raw materials in parts by weight,

wherein the used defoaming agent is tributyl phosphate, higher alcohol, aliphatic amide, polysiloxane, natural oil or glycerol, and the like, and the used diluent is urea, thiourea, boric acid, and the like; the surfactant is one or more of sodium fatty acid, sodium higher fatty acid, fatty alcohol-polyoxyethylene ether sulfate or sodium pyrophosphate; the drier is one or more of polyvinyl alcohol, calcium carbonate, kaolin, sodium bentonite and the like; the antiseptic is selected from sodium benzoate, acrylic acid, calcium propionate, sodium sulfite, chlorinated hydrocarbons, parabens, etc.

The preparation method of the oxidized corn starch adhesive provided by the embodiment of the invention specifically comprises the following steps:

1) preparing the raw materials according to the proportion, wherein water is deionized water, one part of the raw materials is used for dissolving corn starch, and the other part of the raw materials is used for dissolving other raw materials.

2) Adding corn starch into a reactor, adding water, continuously stirring until a uniform milky suspension is formed, adding a catalyst, heating and stirring for 20-40 min, and performing pre-gelatinization.

3) After pregelatinization, H is added₂O₂And dropwise adding NaOH to adjust the pH to be 8-10 under continuous stirring, and heating and stirring for 1-2 h for oxidation.

4) And after oxidation, adding the rest NaOH, stirring for 25-40 min, and pasting.

5) After pasting, adding a cross-linking agent, and stirring for 20-40 min for cross-linking.

6) And after crosslinking, sequentially adding polyacrylamide, stirring for 5-15 min, sequentially adding a defoaming agent, a diluent, a surfactant, a drier and a preservative, and continuously stirring for 20-40 min for modification. Cooling and discharging to obtain the oxidized corn paste starch glue.

Wherein, the heating and stirring in the step 2) are carried out for 15-30 min, the heating temperature is 35-45 ℃, and the catalyst is ferrous sulfate.

Step 3) H₂O₂The mass fraction is 30%, the heating and stirring are carried out for 1.5-2 h, and the heating temperature is 55-70 ℃.

And 4) heating and stirring for 15-30 min, wherein the gelatinization temperature is 55-65 ℃.

And step 5) heating and stirring for 20-40 min, wherein the crosslinking temperature is 55-65 ℃, and the crosslinking agents are borax, sodium metaborate, sodium trimetaphosphate, oxalic acid and the like.

The defoaming agent used in the step 6) is tributyl phosphate, higher alcohol, aliphatic amide, polysiloxane, natural oil or glycerol, and the like, and the diluent is urea, thiourea, boric acid, and the like; the surfactant is one or more of sodium fatty acid, sodium higher fatty acid, sodium alkyl sulfate, sodium alkyl benzene sulfonate, fatty alcohol polyoxyethylene ether sulfate or sodium pyrophosphate; the drier is one or more of polyvinyl alcohol, calcium chloride, calcium carbonate, kaolin, sodium bentonite and the like; the antiseptic is selected from sodium benzoate, acrylic acid, calcium propionate, sodium sulfite, chlorinated hydrocarbons, parabens, etc.

The preparation method of the embodiment of the invention adopts green environment-friendly H₂O₂As an oxidant, ferrous sulfate is used as a catalyst to oxidize the corn starch. The oxidized corn starch paste adhesive provided by the embodiment of the invention can effectively prevent the aggregation of starch macromolecules by adding the surfactant and the polyvinyl alcohol, prevent the aging of starch glue and enhance the stability of the adhesive. The oxidized corn starch paste adhesive disclosed by the embodiment of the invention enhances the flexibility and initial adhesion of starch glue by adding polyacrylamide. The oxidized corn starch paste adhesive of the embodiment of the invention enhances the toughness of starch glue by adding a diluent. The invention relates to an oxidized corn starch paste adhesiveThe drying speed is improved and the solid content is increased by adding the drier. The invention has the advantages of simple and easily obtained raw materials, environmental protection and no public nuisance. The oxidized corn starch paste adhesive is prepared from corn starch, NaOH and H₂O₂The catalyst, the surfactant, the polyacrylamide, the cross-linking agent, the drier, the diluent and the like are used as raw materials and are prepared by a series of chemical reactions such as pre-gelatinization, cross-linking, modification and the like. The oxidized corn paste adhesive provided by the invention has the advantages of strong initial viscosity, large adhesive force, good fluidity and good stability. And the oxidized corn paste adhesive has the advantages of simple and easy process, convenient production, environment-friendly raw materials and low price.