CN110219204B

CN110219204B - Moisture-resistant dry strength agent for kraft paper and preparation method thereof

Info

Publication number: CN110219204B
Application number: CN201910521528.6A
Authority: CN
Inventors: 朱江华; 龚本华; 严慧
Original assignee: Nanchang City Longran Industry Co ltd
Current assignee: Nanchang City Longran Industry Co ltd
Priority date: 2019-06-17
Filing date: 2019-06-17
Publication date: 2021-12-07
Anticipated expiration: 2039-06-17
Also published as: CN110219204A

Abstract

The invention relates to the field of dry strength agents for paper, and provides a moisture-resistant dry strength agent for kraft paper, which at least comprises the following raw materials: amphoteric polyacrylamide emulsion, modified guar gum, ammonium salt and diatomite; the weight ratio of the amphoteric polyacrylamide emulsion to the modified guar gum to the ammonium salt to the diatomite is 1: (0.1-0.5): (0.1-0.5): (0.01-0.1). Also provides a preparation method of the moisture-resistant dry strength agent for kraft paper.

Description

Moisture-resistant dry strength agent for kraft paper and preparation method thereof

Technical Field

The invention relates to the field of dry strength agents for paper, in particular to a moisture-resistant dry strength agent for kraft paper and a preparation method thereof.

Background

Dry strength agents are an important class of chemicals in the paper industry to enhance paper strength, and are commonly used to compensate for the decrease in paper strength caused by the addition of fillers or low grade fibers. Many water soluble polymers that form hydrogen bonds with fibers can be dry strength agents. The commonly used dry strength agents include natural polymers such as starch and modified substances thereof, synthetic polymers such as polyacrylamide, polyvinyl alcohol and other water-soluble natural product dry strength agents.

Paper strength is affected by many factors, including, among others, the strength of the fibers and the binding strength of the fibers in the paper, and the arrangement and distribution of the paper fibers. The most important is the fiber-to-fiber bonding force, which generally has four types: chemical bonds, hydrogen bonds, van der waals forces, and surface interaction forces. Wherein hydrogen bonding forces are the primary means of creating the bonding strength of the paper. The hydroxyl groups of cellulose molecules are numerous, and the bonding force of hydrogen bonds formed by numerous microfibrils to each other is large, which is also a main cause of strength generation. The natural and synthetic dry strength agents are mostly hydrophilic polymers, the number of hydrogen bonds among fibers is increased by dispersing between the fibers, the purpose of improving the paper strength is achieved, and the binding force between the polymer and the fibers is increased by containing cationic groups connected on main chain rings, so that the polymer retention is improved. The dry strength agent has a common problem in the using process, the viscosity of the obtained polymer is often too high or too low, the problems of gel and coagulation are possibly generated, the utilization rate of materials is reduced, and the loss is increased; in addition, the dry strength agent has poor retention effect in the using process and is easy to cause the pollution problem of white water.

Disclosure of Invention

In order to solve the above technical problems, a first aspect of the present invention provides a moisture-resistant dry strength agent for kraft paper, which comprises at least: amphoteric polyacrylamide emulsion, modified guar gum, ammonium salt and diatomite; the weight ratio of the amphoteric polyacrylamide emulsion to the modified guar gum to the ammonium salt to the diatomite is 1: (0.1-0.5): (0.1-0.5): (0.01-0.1).

As a preferred technical solution, the amphoteric polyacrylamide emulsion of the present invention at least comprises the following raw materials: one or more of component A, olefine acid substances and acrylamide monomers; the preparation raw materials of the component A at least comprise: methoxy-containing enamide derivatives.

As a preferred technical scheme, the raw materials for preparing the modified guar gum in the invention at least comprise guar gum, acid anhydride and amine substances.

As a preferable technical scheme, the weight ratio of the component A, the olefine acid substances and the acrylamide monomers is 1: (0.5-1.5): (2.5-4.5).

As a preferred technical scheme, the number of carbon atoms in the olefinic acid substances is 4-8.

As a preferable technical scheme, the raw material for preparing the component A also comprises chloralkane with 5-10 carbon atoms.

As a preferable technical scheme, the weight ratio of the guar gum, the acid anhydride and the amine substance in the invention is 1: (0.1-0.5): (0.2-0.8).

In a preferred embodiment, the olefinic acid is selected from one or more of itaconic acid, citraconic acid, [ (2-methyl-2-propen-1-yl) oxy ] acetic acid, and 4-methyl-4-pentenoic acid.

As a preferable technical scheme, the amine substance in the invention is long-chain alkyl ammonium chloride with hydroxyethyl.

The second aspect of the invention provides a preparation method of the dry strength agent for kraft paper, which at least comprises the steps of adding the amphoteric polyacrylamide emulsion, the modified guar gum, the ammonium salt and the diatomite into deionized water, and uniformly stirring to obtain the dry strength agent.

The technical features, content and advantages described in the previous sections of the invention will be more readily understood by reference to the following details.

Detailed Description

Unless otherwise indicated, implied from the context, or customary in the art, all parts and percentages herein are by weight and the testing and characterization methods used are synchronized with the filing date of the present application. To the extent that a definition of a particular term disclosed in the prior art is inconsistent with any definitions provided herein, the definition of the term provided herein controls.

The technical features of the technical solutions provided by the present invention are further clearly and completely described below with reference to the specific embodiments, and the scope of protection is not limited thereto.

The words "preferred", "preferably", "more preferred", and the like, in the present invention, refer to embodiments of the invention that may provide certain benefits, under certain circumstances. However, other embodiments may be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention. The sources of components not mentioned in the present invention are all commercially available.

The invention provides a moisture-resistant dry strength agent for kraft paper, which at least comprises the following raw materials: amphoteric polyacrylamide emulsion, modified guar gum, ammonium salt and diatomite; the weight ratio of the amphoteric polyacrylamide emulsion to the modified guar gum to the ammonium salt to the diatomite is 1: (0.1-0.5): (0.1-0.5): (0.01-0.1).

As a preferred technical scheme, the weight ratio of the amphoteric polyacrylamide emulsion, the modified guar gum, the ammonium salt and the diatomite is 1: (0.3-0.5): (0.1-0.3): (0.05-0.1); more preferably, the weight ratio of the amphoteric polyacrylamide emulsion, the modified guar gum, the ammonium salt and the diatomite is 1: 0.4: 0.2: 0.08.

amphoteric polyacrylamide emulsion

In some embodiments, the amphoteric polyacrylamide emulsion comprises at least the following raw materials: one or more of component A, olefine acid substances and acrylamide monomers; the preparation raw materials of the component A at least comprise: methoxy-containing enamide derivatives.

In some embodiments, the amphoteric polyacrylamide emulsion is prepared from the following raw materials: the component A, an olefine acid substance and an acrylamide monomer.

In some embodiments, the weight ratio of the a component, the olefinic acid species, and the acrylamide-based monomer is 1: (0.5-1.5): (2.5-4.5); preferably, the weight ratio of the component A, the olefine acid substances and the acrylamide monomers is 1: (0.8-1.2): (3-4); preferably, the weight ratio of the component A, the olefine acid substances and the acrylamide monomers is 1: 1: 3.5.

in some embodiments, the starting materials for the preparation of the a component include at least: methoxy-containing enamide derivatives.

In some embodiments, the methoxy-containing enamide derivative is selected from the group consisting of N, N-bis (1-methoxyethyl) undec-10-enamide, a combination of one or more of (2, 2-dimethoxyethyl) acrylamide, N- (2, 2-dimethoxyethyl) methacrylamide; preferably, the methoxy-containing enamide derivative is selected from one or more of N, N-di (1-methoxyethyl) undec-10-enamide and (2, 2-dimethoxyethyl) acrylamide; more preferably, the methoxy-containing enamide derivative is N, N-bis (1-methoxyethyl) undec-10-enamide.

In some embodiments, the preparation raw material of the component A also comprises chloralkane with 5-10 carbon atoms; preferably, the preparation raw material of the component A also comprises chloralkane with 6-9 carbon atoms; more preferably, the preparation raw material of the component A also comprises chloralkane with 7 carbon atoms.

In some embodiments, the weight ratio of the methoxy-containing enamide derivative to the chloroalkane is 1: (0.5 to 1.5); preferably, the weight ratio of the methoxy-containing enamide derivative to the chloralkane is 1: (0.6 to 1.3); more preferably, the weight ratio of the methoxy-containing enamide derivative to the chloroalkane is 1: 0.8.

in some embodiments, the chlorinated alkane is selected from the group consisting of 3-chlorodecane, 2-chloroheptane, 1, 2-dichloroheptane, 2, 5-dichlorohexane, 1, 2-dichlorohexane, 1, 6-dichlorohexane, 3-chlorooctane, 1-dichlorooctane, 1, 2-dichlorooctane, 2, 6-dichloroheptane, 1-dichloroheptane, 1, 2-dichlorononane, 1-chlorodecane, 1, 10-dichlorodecane in one or more combinations; preferably, the chloroalkane is selected from one or more of 3-chlorodecane, 2-chloroheptane, 1, 2-dichloroheptane, 3-chlorooctane, 1-dichlorooctane and 1, 2-dichlorooctane; more preferably, the chloroalkane is selected from one or more of 3-chlorodecane, 2-chloroheptane, and 1, 2-dichloroheptane; further preferably, the chloroalkane is 1, 2-dichloroheptane.

In some embodiments, the olefinic acid has a number of carbon atoms from 4 to 8; preferably, the number of carbon atoms in the olefinic acid substance is 5-7; more preferably, the number of carbon atoms in the olefinic acid species is 6.

In some embodiments, the olefinic acid is selected from the group consisting of one or more of itaconic acid, citraconic acid, [ (2-methyl-2-propen-1-yl) oxy ] acetic acid, 4-methyl-4-pentenoic acid; preferably, the olefinic acid substance is selected from one or more of itaconic acid, citraconic acid and 4-methyl-4-pentenoic acid; further preferably, the olefinic acid is 4-methyl-4-pentenoic acid.

In some embodiments, the acrylamide-based monomer is selected from the group consisting of acrylamide, methylolacrylamide, methacrylamide, N-tert-butylacrylamide in combination with one or more; preferably, the acrylamide monomer is selected from one or more of hydroxymethyl acrylamide and N-tertiary butyl acrylamide; more preferably, the acrylamide-based monomer is N-t-butylacrylamide.

The preparation method of the amphoteric polyacrylamide emulsion comprises the following steps:

(1) stirring the methoxy-containing enamide derivative and ether solution of chloroalkane at room temperature for 40-80 h; filtering the precipitate, washing with diethyl ether, and vacuum drying to obtain component A; wherein the weight ratio of the total weight of the methoxy-containing enamide derivative and the chloroalkane to the diethyl ether is 1: (2-4);

(2) placing the component A, the olefinic acid substances, the acrylamide monomer and the initiator into deionized water, and reacting for 7-10 hours at the temperature of 60-80 ℃ to obtain amphoteric polyacrylamide emulsion; wherein the initiator accounts for 0.01-0.05% of the total mass of the component A, the olefinic acid substance and the acrylamide monomer.

Preferably, the preparation method of the amphoteric polyacrylamide emulsion comprises the following steps:

(1) stirring the methoxy-containing enamide derivative and ether solution of chloroalkane for 72 hours at room temperature; filtering the precipitate, washing with diethyl ether, and vacuum drying to obtain component A; wherein the weight ratio of the total weight of the methoxy-containing enamide derivative and the chloroalkane to the diethyl ether is 1: 3;

(2) placing the component A, the olefinic acid substances, the acrylamide monomers and the initiator into deionized water, and reacting for 8.5 hours at 70 ℃ to obtain amphoteric polyacrylamide emulsion; wherein the initiator accounts for 0.03 percent of the total mass of the component A, the olefinic acid substance and the acrylamide monomer.

In some embodiments, the initiator is selected from one or more combinations of sodium persulfate, potassium persulfate, ammonium persulfate, hydrogen peroxide, t-butyl hydroperoxide, cyclohexanone peroxide, benzoyl peroxide, azo-type initiators, and percarbonate; preferably, the initiator is benzoyl peroxide.

Experiments show that when N, N-bis (1-methoxyethyl) undec-10-enamide and olefinic acid substances with 4-8 carbon atoms are adopted in the preparation process of the amphoteric polyacrylamide emulsion, the usability of a dry strength agent in the preparation process of paper can be effectively improved, namely the white water pollution is reduced, the problems of air bubbles and coagulation are reduced, the strength and the water resistance of the paper are improved, and due to the fact that polyacrylamide is prepared by an anionic monomer of a short branched chain and a cationic monomer of a long branched chain, a molecular structure with alternate long and short branched chains is formed, excessive cations can be effectively avoided, and cationization is generated in the preparation process of the paper; the carboxyl carbon chains with proper length can prevent anions and cations from having strong action to block the action of the anions and the cations with paper fibers, so that the strength of the paper is improved; meanwhile, the ion exchange resin is easy to act with impurity cations swimming in molecular gaps, so that the migration of the ion exchange resin is prevented, and the retention rate is improved.

In addition, the N, N-bis (1-methoxyethyl) undec-10-enamide is beneficial to the formation of an amphoteric molecular structure with an asymmetric structure and alternate long and short branched chains, so that over-cationization is avoided, the molecular dispersibility in the emulsion preparation process is improved, and the monomer conversion rate is improved, so that the solid content of a system is improved, the retention rate is improved under the combined action of positive and negative charges in the system in the paper preparation process, and the generation of gel is avoided while the retention rate is improved; meanwhile, the asymmetric structure of the composite material reduces the surface tension, promotes the uniformity of a system, and avoids the problem of generating bubbles due to different activities in the preparation process.

Modified guar gum

In some embodiments, the raw materials for preparing the modified guar gum at least comprise guar gum, acid anhydride and amine substances.

In some embodiments, the weight ratio of guar gum, anhydride, amine is 1: (0.1-0.5): (0.2-0.8); preferably, the weight ratio of the guar gum, the acid anhydride and the amine substance is 1: (0.3-0.4): (0.4-0.6); more preferably, the weight ratio of the guar gum, the acid anhydride and the amine substance is 1: 0.35: 0.5.

the purchase manufacturer of the guar gum is not specially limited, and the guar gum is purchased from Guanpu Biotech limited, Shandong and is named as guar raw powder.

In some embodiments, the anhydride is selected from the group consisting of maleic anhydride, succinic anhydride, 1-dodecenyl succinic anhydride, acrylic anhydride, 2-methylene succinic anhydride, 2-decen-1-yl succinic anhydride, and combinations of one or more thereof; preferably, the anhydride is selected from one or more of maleic anhydride, 1-dodecenyl succinic anhydride, acrylic anhydride and 2-decen-1-yl succinic anhydride; more preferably, the anhydride is maleic anhydride.

In some embodiments, the amine species is a long-chain alkyl ammonium chloride with a hydroxyethyl group.

The long-chain alkyl ammonium chloride represents 10-20 continuous methylene alkyl ammonium chloride contained in the molecular structure.

In some embodiments, the long alkyl ammonium chloride with a hydroxyethyl group is selected from the group consisting of one or more combinations of bis (2-hydroxyethyl) -methyl-undecanyl ammonium chloride, bis (hydroxyethyl) methyldodecyl ammonium chloride, bis (2-hydroxyethyl) -methyl-tridecyl ammonium chloride; preferably, the long-chain alkyl ammonium chloride with hydroxyethyl group is di (2-hydroxyethyl) -methyl-undecanyl ammonium chloride and/or di (2-hydroxyethyl) -methyl-tridecyl ammonium chloride; further preferably, the long-chain alkyl ammonium chloride with hydroxyethyl group is di (2-hydroxyethyl) -methyl-tridecyl ammonium chloride.

In some embodiments, the modified guar is prepared as follows:

weighing a certain amount of guar gum, acid anhydride and amine substances, placing the guar gum, the acid anhydride and the amine substances into a reactor, preparing sodium bicarbonate into an aqueous solution, uniformly spraying the aqueous solution into a system, stirring while spraying, placing the aqueous solution into a water bath at 50-80 ℃ in a closed state, and ensuring that the reaction is carried out in a water vapor environment; after the reaction is completed, washing, filtering and drying the product with absolute ethyl alcohol for multiple times to obtain pure modified guar gum; the mass ratio of the total mass of the guar gum, the anhydride and the amine substances to the sodium bicarbonate is 1: (0.05-0.1); the mass ratio of the total mass of the guar gum, the anhydride and the amine substances to the water is 1: (1.5-3.5).

Preferably, the preparation method of the modified guar gum comprises the following steps:

weighing a certain amount of guar gum, acid anhydride and amine substances, placing the guar gum, the acid anhydride and the amine substances into a reactor, preparing sodium bicarbonate into an aqueous solution, uniformly spraying the aqueous solution into a system, stirring while spraying, placing the aqueous solution into a 70 ℃ water bath in a closed state, and ensuring that the reaction is carried out in a water vapor environment; after the reaction is completed, washing, filtering and drying the product with absolute ethyl alcohol for multiple times to obtain pure modified guar gum; the mass ratio of the total mass of the guar gum, the anhydride and the amine substances to the sodium bicarbonate is 1: 0.08; the mass ratio of the total mass of the guar gum, the anhydride and the amine substances to the water is 1: 2.5.

experiments show that the guar gum is added in the preparation process of paper to improve the strength of the paper, but the water resistance is low, bubbles are generated in the preparation process, a large amount of active hydroxyl groups on the outer side of molecules contained in guar gum molecules have large hydrogen bond bonding area when being bonded with fibers, the formed hydrogen bond bonding distance is short, the bonding force is large, the guar gum molecules are easily bonded with the fibers to generate a sizing effect, the strength of the paper and the compactness and evenness of the paper are improved, but the guar gum molecules are compatible with system blending, and in the sizing process, the molecules contain large ring structures, although the speed of reducing the surface tension can be accelerated, the degree of reducing the surface tension is limited due to the limitation of the freedom of the molecular structures, when the guar gum is singly used, the bubbles are generated to influence the acting force of a dry strength agent and the paper, the strength and the toughness are reduced, the molecular bridges in the paper can be reduced, the evenness in the paper is reduced, and the phenomena of water intolerance and the like are caused.

In the experimental process, the maleic anhydride and the amine substance are adopted to modify the guar gum, so that the strength of the paper can be improved, the white water pollution can be reduced, and the water resistance of the paper can be improved; meanwhile, the carbon chain can migrate to the fiber pores in the preparation process, so that the water resistance is improved; the hydrophobic branched chain structure can act together with the large circular ring to form a uniform and compact hydrophobic layer on the surface of the paper, and the strength, toughness and water resistance of the system are also improved; in addition, a uniform and compact carbon chain hydrophobic layer can be formed on the surface of the paper due to the combined action of the modified guar gum and the polyacrylic acid emulsion, so that the water resistance, the strength and the toughness of the paper are improved.

Ammonium salts

In some embodiments, the ammonium salt is selected from the group consisting of DTAC, DTAB, TTAC, TTAB, CTAC, CTAB, and combinations of any one or more thereof; preferably, the ammonium salt is selected from any one or a combination of DTAC, DTAB and TTAC; more preferably, the ammonium salt is TTAC.

The DTAC is the abbreviation of dodecyl trimethyl ammonium chloride, and the CAS number is 112-00-5; the DTAB is the abbreviation of lauryl trimethyl ammonium bromide, and the CAS number is 1119-94-4; TTAC is short for tetradecyl trimethyl ammonium chloride, and CAS number is 4574-04-3; the TTAB is short for tetradecyl trimethyl ammonium bromide, and the CAS number is 1119-97-7; the CTAC is the abbreviation of hexadecyl trimethyl ammonium chloride, and the CAS number is 112-02-7; CTAB is abbreviation of cetyl trimethyl bromide, CAS number is 57-09-0.

Diatomite

In some embodiments, the diatomaceous earth has an average particle size of 5 to 15 μm; preferably, the average particle size of the diatomite is 5-12 μm; more preferably, the average particle size of the diatomite is 5-9 μm; more preferably, the diatomaceous earth has an average particle size of 6 μm.

Experiments show that when the diatomite with the diameter of 5-12 micrometers is adopted, due to the structures of hydroxyl, silicon and the like on the surface of the diatomite, the diatomite can be well dispersed in gaps of branched chains, one part of the diatomite acts with paper fibers and is adsorbed on the surface of paper, the reinforcing effect is achieved, one part of the diatomite is well fixed in molecular gaps, the strength of the paper is improved, meanwhile, the diatomite serves as a steric hindrance, the molecules are prevented from being excessively wound, the acting force between polyacrylamide and modified guar gum molecules is well kept, and the problems of coagulation or excessive coagulation of the paper fibers and the like caused by excessive cohesive force are avoided; in addition, the paper can act with anion garbage in the system, reduce the pollution of white water and the consumption of cations, and further improve the strength of the paper.

When the average particle size of the diatomite is larger, the diatomite has larger steric hindrance in a molecular system, is not easy to disperse, is easy to form coagulation and accumulate on the surface of paper, and thus causes the problems of uneven paper strength and uneven paper surface; when the average particle size of the diatoms is too small, the diatoms are easy to migrate to fiber pores in the preparation process, the paper strengthening effect is avoided, meanwhile, the steric hindrance is small, the static effect between polyacrylamide and modified guar gum molecules is easy to be large, the uniformity of a system is damaged, the problems of coagulation, bubbles and the like occur in the preparation process, and the strength and the water resistance of the obtained paper are reduced.

In some preferred embodiments, the preparation method of the dry strength agent for kraft paper at least comprises the steps of adding the amphoteric polyacrylamide emulsion, the modified guar gum, the ammonium salt and the diatomite into deionized water, stirring for 1.5-2.5 hours at 75-85 ℃, cooling to room temperature, and uniformly stirring to obtain the dry strength agent.

In some more preferred embodiments, the preparation method of the dry strength agent for kraft paper at least comprises the steps of adding the amphoteric polyacrylamide emulsion, the modified guar gum, the ammonium salt and the diatomite into deionized water, stirring for 2 hours at 80 ℃, cooling to room temperature, and uniformly stirring to obtain the dry strength agent.

In some embodiments, the weight ratio of the amphoteric polyacrylamide emulsion to deionized water is 1: (20-40); preferably, the weight ratio of the amphoteric polyacrylamide emulsion to the deionized water is 1: (25-35); more preferably, the weight ratio of the amphoteric polyacrylamide emulsion to the deionized water is 1: 30.

the present invention is described in detail below with reference to examples, which are provided for the purpose of further illustration only and are not to be construed as limiting the scope of the present invention, and the insubstantial modifications and adaptations thereof by those skilled in the art based on the teachings of the present invention will still fall within the scope of the present invention.

The amphoteric polyacrylamide emulsion described in the following examples was prepared as follows:

(2) placing the component A, the olefinic acid substances, the acrylamide monomers and the initiator into deionized water, and reacting for 8.5 hours at 70 ℃ to obtain amphoteric polyacrylamide emulsion; wherein the initiator accounts for 0.03 percent of the total mass of the component A, the olefinic acid substance and the acrylamide monomer; the initiator is benzoyl peroxide.

The preparation method of the modified guar gum comprises the following steps:

example 1

The preparation raw materials of the wet-resistant dry strength agent for kraft paper comprise: amphoteric polyacrylamide emulsion, modified guar gum, ammonium salt and diatomite; the weight ratio of the amphoteric polyacrylamide emulsion to the modified guar gum to the ammonium salt to the diatomite is 1: 0.4: 0.2: 0.08;

the preparation raw materials of the amphoteric polyacrylamide emulsion comprise: the composition of the component A, an olefine acid substance and an acrylamide monomer is prepared from the following components in a weight ratio of 1: 1: 3.5; the raw materials for preparing the component A comprise methoxy-containing enamide derivatives and chloralkane, wherein the weight ratio of the methoxy-containing enamide derivatives to the chloralkane is 1: 0.8; the methoxy-containing enamide derivative is N, N-di (1-methoxyethyl) undec-10-enamide, and the chloralkane is 1, 2-dichloroheptane; the olefine acid substance is 4-methyl-4-pentenoic acid; the acrylamide monomer is N-tert-butyl acrylamide;

the modified guar gum is prepared from the raw materials of guar gum, acid anhydride and amine substances in a weight ratio of 1: 0.35: 0.5; the acid anhydride is maleic anhydride, and the amine substance is bis (2-hydroxyethyl) -methyl-tridecyl ammonium chloride; the ammonium salt is TTAC; the diatomite is purchased from Qingdao Shengtai silicon industry Co., Ltd and has the brand number of TZ 525;

a preparation method of the dry strength agent for kraft paper comprises the steps of adding amphoteric polyacrylamide emulsion, modified guar gum, ammonium salt and diatomite into deionized water, stirring for 2 hours at 80 ℃, cooling to room temperature, and uniformly stirring to obtain the dry strength agent; the weight ratio of the amphoteric polyacrylamide emulsion to the deionized water is 1: 30.

example 2

The preparation raw materials of the wet-resistant dry strength agent for kraft paper comprise: amphoteric polyacrylamide emulsion, modified guar gum, ammonium salt and diatomite; the weight ratio of the amphoteric polyacrylamide emulsion to the modified guar gum to the ammonium salt to the diatomite is 1: 0.1: 0.1: 0.01;

the preparation raw materials of the amphoteric polyacrylamide emulsion comprise: the composition of the component A, an olefine acid substance and an acrylamide monomer is prepared from the following components in a weight ratio of 1: 0.5: 2.5; the preparation raw material of the component A comprises methoxy-containing enamide derivatives and chloralkane, and the weight ratio of the methoxy-containing enamide derivatives to the chloralkane is 1: 0.5; the methoxy-containing enamide derivative is N, N-di (1-methoxyethyl) undec-10-enamide, and the chloralkane is 2-chloroheptane; the olefinic acid substance is itaconic acid; the acrylamide monomer is hydroxymethyl acrylamide;

the modified guar gum is prepared from the raw materials of guar gum, acid anhydride and amine substances in a weight ratio of 1: 0.1: 0.2; the acid anhydride is maleic anhydride, and the amine substance is bis (2-hydroxyethyl) -methyl-undecane ammonium chloride; the ammonium salt is DTAB; the diatomite is purchased from Qingdao Shengtai silicon industry Co., Ltd and has the brand number of TZ 200;

a preparation method of the dry strength agent for kraft paper comprises the steps of adding amphoteric polyacrylamide emulsion, modified guar gum, ammonium salt and diatomite into deionized water, stirring for 1.5 hours at 75 ℃, cooling to room temperature, and uniformly stirring to obtain the dry strength agent; the weight ratio of the amphoteric polyacrylamide emulsion to the deionized water is 1: 20.

example 3

The preparation raw materials of the wet-resistant dry strength agent for kraft paper comprise: amphoteric polyacrylamide emulsion, modified guar gum, ammonium salt and diatomite; the weight ratio of the amphoteric polyacrylamide emulsion to the modified guar gum to the ammonium salt to the diatomite is 1: 0.5: 0.5: 0.1;

the preparation raw materials of the amphoteric polyacrylamide emulsion comprise: the composition of the component A, an olefine acid substance and an acrylamide monomer is prepared from the following components in a weight ratio of 1: 1.5: 4.5; the preparation raw material of the component A comprises methoxy-containing enamide derivatives and chloralkane, and the weight ratio of the methoxy-containing enamide derivatives to the chloralkane is 1: 1.5; the methoxy-containing enamide derivative is N, N-di (1-methoxyethyl) undec-10-enamide, and the chloroalkane is 3-chlorodecane; the olefine acid substance is 4-methyl-4-pentenoic acid; the acrylamide monomer is N-tert-butyl acrylamide;

the modified guar gum is prepared from the raw materials of guar gum, acid anhydride and amine substances in a weight ratio of 1: 0.5: 0.8; the acid anhydride is maleic anhydride, and the amine substance is bis (2-hydroxyethyl) -methyl-undecane ammonium chloride; the ammonium salt is DTAC; the diatomite is purchased from Qingdao Shengtai silicon industry Co., Ltd, and the brand is TZ 325;

a preparation method of the dry strength agent for kraft paper comprises the steps of adding amphoteric polyacrylamide emulsion, modified guar gum, ammonium salt and diatomite into deionized water, stirring for 2.5 hours at 85 ℃, cooling to room temperature, and uniformly stirring to obtain the dry strength agent; the weight ratio of the amphoteric polyacrylamide emulsion to the deionized water is 1: 40.

example 4

The preparation raw materials of the wet-resistant dry strength agent for kraft paper comprise: amphoteric polyacrylamide emulsion, modified guar gum, ammonium salt and diatomite; the weight ratio of the amphoteric polyacrylamide emulsion to the modified guar gum to the ammonium salt to the diatomite is 1: 0.3: 0.1: 0.05;

the preparation raw materials of the amphoteric polyacrylamide emulsion comprise: the composition of the component A, an olefine acid substance and an acrylamide monomer is prepared from the following components in a weight ratio of 1: 0.8: 3; the preparation raw material of the component A comprises methoxy-containing enamide derivatives and chloralkane, and the weight ratio of the methoxy-containing enamide derivatives to the chloralkane is 1: 0.5; the methoxy-containing enamide derivative is N, N-di (1-methoxyethyl) undec-10-enamide, and the chloroalkane is 3-chlorodecane; the olefine acid substance is 4-methyl-4-pentenoic acid; the acrylamide monomer is N-tert-butyl acrylamide;

the modified guar gum is prepared from the raw materials of guar gum, acid anhydride and amine substances in a weight ratio of 1: 0.3: 0.4; the acid anhydride is maleic anhydride, and the amine substance is bis (2-hydroxyethyl) -methyl-undecane ammonium chloride; the ammonium salt is DTAC; the diatomite is purchased from Qingdao Shengtai silicon industry Co., Ltd and has the brand number of TZ 525;

a preparation method of the dry strength agent for kraft paper comprises the steps of adding amphoteric polyacrylamide emulsion, modified guar gum, ammonium salt and diatomite into deionized water, stirring for 2 hours at 80 ℃, cooling to room temperature, and uniformly stirring to obtain the dry strength agent; the weight ratio of the amphoteric polyacrylamide emulsion to the deionized water is 1: 25.

example 5

The preparation raw materials of the wet-resistant dry strength agent for kraft paper comprise: amphoteric polyacrylamide emulsion, modified guar gum, ammonium salt and diatomite; the weight ratio of the amphoteric polyacrylamide emulsion to the modified guar gum to the ammonium salt to the diatomite is 1: 0.5: 0.3: 0.1;

the preparation raw materials of the amphoteric polyacrylamide emulsion comprise: the composition of the component A, an olefine acid substance and an acrylamide monomer is prepared from the following components in a weight ratio of 1: 1.2: 4; the preparation raw material of the component A comprises methoxy-containing enamide derivatives and chloralkane, and the weight ratio of the methoxy-containing enamide derivatives to the chloralkane is 1: 1.3; the methoxy-containing enamide derivative is N, N-di (1-methoxyethyl) undec-10-enamide, and the chloroalkane is 3-chlorodecane; the olefine acid substance is 4-methyl-4-pentenoic acid; the acrylamide monomer is N-tert-butyl acrylamide;

the modified guar gum is prepared from the raw materials of guar gum, acid anhydride and amine substances in a weight ratio of 1: 0.4: 0.6; the acid anhydride is maleic anhydride, and the amine substance is bis (2-hydroxyethyl) -methyl-undecane ammonium chloride; the ammonium salt is DTAC; the diatomite is purchased from Qingdao Shengtai silicon industry Co., Ltd and has the brand number of TZ 525;

a preparation method of the dry strength agent for kraft paper comprises the steps of adding amphoteric polyacrylamide emulsion, modified guar gum, ammonium salt and diatomite into deionized water, stirring for 2 hours at 80 ℃, cooling to room temperature, and uniformly stirring to obtain the dry strength agent; the weight ratio of the amphoteric polyacrylamide emulsion to the deionized water is 1: 35.

example 6

the preparation raw materials of the amphoteric polyacrylamide emulsion comprise: the composition of the component A, an olefine acid substance and an acrylamide monomer is prepared from the following components in a weight ratio of 1: 1: 3.5; the preparation raw material of the component A comprises methoxy-containing enamide derivatives and chloralkane, and the weight ratio of the methoxy-containing enamide derivatives to the chloralkane is 1: 0.8; the methoxy-containing enamide derivative is (2, 2-dimethoxyethyl) acrylamide, and the chloralkane is 1, 2-dichloroheptane; the olefine acid substance is 4-methyl-4-pentenoic acid; the acrylamide monomer is N-tert-butyl acrylamide;

example 7

the preparation raw materials of the amphoteric polyacrylamide emulsion comprise: the composition of the component A, an olefine acid substance and an acrylamide monomer is prepared from the following components in a weight ratio of 1: 1: 3.5; the preparation raw material of the component A comprises methoxy-containing enamide derivatives and chloralkane, and the weight ratio of the methoxy-containing enamide derivatives to the chloralkane is 1: 0.8; the methoxy-containing enamide derivative is N, N-di (1-methoxyethyl) undec-10-enamide, and the chloralkane is 1-chloropentane; the olefine acid substance is 4-methyl-4-pentenoic acid; the acrylamide monomer is N-tert-butyl acrylamide;

example 8

the preparation raw materials of the amphoteric polyacrylamide emulsion comprise: the composition of the component A, an olefine acid substance and an acrylamide monomer is prepared from the following components in a weight ratio of 1: 1: 3.5; the preparation raw material of the component A comprises methoxy-containing enamide derivatives and chloralkane, and the weight ratio of the methoxy-containing enamide derivatives to the chloralkane is 1: 0.8; the methoxy-containing enamide derivative is N, N-di (1-methoxyethyl) undec-10-enamide, and the chloralkane is 2-chlorododecane; the olefine acid substance is 4-methyl-4-pentenoic acid; the acrylamide monomer is N-tert-butyl acrylamide;

example 9

the preparation raw materials of the amphoteric polyacrylamide emulsion comprise: the composition of the component A, an olefine acid substance and an acrylamide monomer is prepared from the following components in a weight ratio of 1: 1: 3.5; the preparation raw material of the component A comprises methoxy-containing enamide derivatives and chloralkane, and the weight ratio of the methoxy-containing enamide derivatives to the chloralkane is 1: 0.8; the methoxy-containing enamide derivative is N, N-di (1-methoxyethyl) undec-10-enamide, and the chloralkane is 1, 2-dichloroheptane; the olefinic acid substance is acrylic acid; the acrylamide monomer is N-tert-butyl acrylamide;

example 10

the preparation raw materials of the amphoteric polyacrylamide emulsion comprise: the composition of the component A, an olefine acid substance and an acrylamide monomer is prepared from the following components in a weight ratio of 1: 1: 3.5; the preparation raw material of the component A comprises methoxy-containing enamide derivatives and chloralkane, and the weight ratio of the methoxy-containing enamide derivatives to the chloralkane is 1: 0.8; the methoxy-containing enamide derivative is N, N-di (1-methoxyethyl) undec-10-enamide, and the chloralkane is 1, 2-dichloroheptane; the olefinic acid substance is 3-decenoic acid; the acrylamide monomer is N-tert-butyl acrylamide;

example 11

the preparation raw materials of the amphoteric polyacrylamide emulsion comprise: the composition of the component A, an olefine acid substance and an acrylamide monomer is prepared from the following components in a weight ratio of 1: 0.1: 1; the preparation raw material of the component A comprises methoxy-containing enamide derivatives and chloralkane, and the weight ratio of the methoxy-containing enamide derivatives to the chloralkane is 1: 0.8; the methoxy-containing enamide derivative is N, N-di (1-methoxyethyl) undec-10-enamide, and the chloralkane is 1, 2-dichloroheptane; the olefine acid substance is 4-methyl-4-pentenoic acid; the acrylamide monomer is N-tert-butyl acrylamide;

example 12

the preparation raw materials of the amphoteric polyacrylamide emulsion comprise: the composition of the component A, an olefine acid substance and an acrylamide monomer is prepared from the following components in a weight ratio of 1: 1: 3.5; the preparation raw material of the component A comprises methoxy-containing enamide derivatives and chloralkane, and the weight ratio of the methoxy-containing enamide derivatives to the chloralkane is 1: 0.8; the methoxy-containing enamide derivative is N, N-di (1-methoxyethyl) undec-10-enamide, and the chloralkane is 1, 2-dichloroheptane; the olefine acid substance is 4-methyl-4-pentenoic acid; the acrylamide monomer is N-tert-butyl acrylamide;

the modified guar gum is prepared from the raw materials of guar gum, acid anhydride and amine substances in a weight ratio of 1: 0.35: 0.5; the acid anhydride is maleic anhydride, and the amine substance is (2-hydroxyethyl) dimethyl octadecyl ammonium chloride; the ammonium salt is TTAC; the diatomite is purchased from Qingdao Shengtai silicon industry Co., Ltd and has the brand number of TZ 525;

example 13

the modified guar gum is prepared from the raw materials of guar gum, acid anhydride and amine substances in a weight ratio of 1: 0.35: 0.5; the acid anhydride is maleic anhydride, and the amine substance is bis (hydroxyethyl) methyl dodecyl ammonium chloride; the ammonium salt is TTAC; the diatomite is purchased from Qingdao Shengtai silicon industry Co., Ltd and has the brand number of TZ 525;

example 14

the modified guar gum is prepared from the raw materials of guar gum, acid anhydride and amine substances in a weight ratio of 1: 0.35: 0.5; the acid anhydride is acrylic anhydride, and the amine substance is bis (2-hydroxyethyl) -methyl-tridecyl ammonium chloride; the ammonium salt is TTAC; the diatomite is purchased from Qingdao Shengtai silicon industry Co., Ltd and has the brand number of TZ 525;

example 15

the modified guar gum is prepared from the raw materials of guar gum, acid anhydride and amine substances in a weight ratio of 1: 0.35: 0.5; the acid anhydride is maleic anhydride, and the amine substance is bis (2-hydroxyethyl) -methyl-tridecyl ammonium chloride; the ammonium salt is TTAC; the diatomite is purchased from Qingdao Shengtai silicon industry Co., Ltd and is of a brand number TZ 030;

example 16

the modified guar gum is prepared from the raw materials of guar gum, acid anhydride and amine substances in a weight ratio of 1: 0.35: 0.5; the acid anhydride is maleic anhydride, and the amine substance is bis (2-hydroxyethyl) -methyl-tridecyl ammonium chloride; the ammonium salt is TTAC; the diatomite is purchased from Qingdao Shengtai silicon industry Co., Ltd and has the brand number of TZ 825;

performance testing

The use process comprises the following steps: adding water to dilute the dry strength agent to 1 wt% for later use, preparing paper pulp, wherein the beating degree is 30 DEG SR, and adding the diluted dry strength agent into the paper pulp, wherein the adding amount is 12 kg/t. The paper pulp is evenly stirred, and the quantitative sheet making quantity is 80g/m²After being dried in the air, the composite board is subjected to various strength tests, and the object is kraft paper; wherein, the paper without the dry strength agent is used as one blank group.

1. Usability test: observing whether the dry strength agent generates precipitates and bubbles in the using process; the effect grades are divided into 3 types;

a: no precipitation or air bubbles are generated;

b: micro-precipitation or bubble generation;

c: significant precipitation or bubble generation.

2. Tensile strength: tensile strength was tested according to GB/T12914-2008.

3. Burst index test: the physical properties of the sheets in the standard GB/T24323-2009 pulp laboratory are measured, and the test results are shown in Table 1. The burst index is a key indicator of kraft strength, the higher the burst index, the higher the burst strength at the same basis weight.

4. Water resistance: and measuring the Cobb value by adopting an XSH type Briggy absorbency tester of automated technology Limited company of Guangtong Boke in Hangzhou state according to a GB/T1540-1989 method.

5. Retention aid effect: the first pass retention rate was calculated according to the differential method, where (%) (concentration of networked pulp-concentration of white water in the net)/concentration of networked pulp × 100%.

TABLE 1

The foregoing examples are illustrative only, and serve to explain some of the features of the present disclosure. The appended claims are intended to claim as broad a scope as is contemplated, and the examples presented herein are merely illustrative of selected implementations in accordance with all possible combinations of examples. Accordingly, it is applicants' intention that the appended claims are not to be limited by the choice of examples illustrating features of the invention. And that advances in science and technology will result in possible equivalents or sub-substitutes not currently contemplated for reasons of inaccuracy in language representation, and such changes should also be construed where possible to be covered by the appended claims.

Claims

1. The wet-resistant dry strength agent for kraft paper is characterized by comprising the following raw materials: amphoteric polyacrylamide emulsion, modified guar gum, ammonium salt and diatomite; the weight ratio of the amphoteric polyacrylamide emulsion to the modified guar gum to the ammonium salt to the diatomite is 1: (0.1-0.5): (0.1-0.5): (0.01 to 0.1); the amphoteric polyacrylamide emulsion comprises the following raw materials: the composition of the component A, olefinic acid substances and acrylamide monomers;

the weight ratio of the component A, the olefine acid substances and the acrylamide monomers is 1: (0.5-1.5): (2.5-4.5);

the preparation raw materials of the component A at least comprise: one or more of N, N-di (1-methoxyethyl) undec-10-enamide and (2, 2-dimethoxyethyl) acrylamide;

the preparation raw material of the component A also comprises chloralkane with 5-10 carbon atoms;

the raw materials for preparing the modified guar gum at least comprise guar gum, acid anhydride and amine substances;

the olefinic acid substance is selected from one or more of itaconic acid, citraconic acid and 4-methyl-4-pentenoic acid.

2. The dry strength agent for kraft paper according to claim 1, wherein the weight ratio of guar gum, acid anhydride and amine substance is 1: (0.1-0.5): (0.2-0.8).

3. The dry strength agent for kraft paper according to claim 1, wherein the amine substance is a long-chain alkyl ammonium chloride having a hydroxyethyl group.

4. A method for preparing the dry strength agent for the kraft paper as claimed in any one of claims 1 to 3, characterized by at least the steps of adding the amphoteric polyacrylamide emulsion, the modified guar gum, the ammonium salt and the diatomite into the deionized water, and uniformly stirring to obtain the dry strength agent.