Method for preparing sizing agent

Abstract

The present invention relates to the field of papermaking. In particular, the present invention relates to a method for preparing a sizing agent. The method of the present invention comprises the following steps: (1) pre-adding a first part of TEA of total TEA to a HEEL-containing reaction system to obtain a TEA-pre-added HEEL-containing reaction system; and (2) adding the remaining second part of TEA of the total TEA and FACl to the TEA-pre-added HEL-containing reaction system, and reacting same, wherein the weight percentage of the first part in the total TEA is not greater than 90% of the total TEA. The present method can reduce the viscosity of reaction systems, and / or achieves toluene-free operation.

Description

A method for preparing a sizing agent Technical Field

[0001] The present invention relates to the field of papermaking and, in particular, to a method for preparing a sizing agent. The method can reduce the viscosity of a reaction system and / or achieve toluene-free operation. Background Art

[0002] Paper is formed by the entanglement of materials containing plant cellulose. Plant cellulose has hydroxyl groups, which gives the paper a certain degree of hydrophilicity. Plant cellulose is also entangled to form a pore structure, which has a capillary effect, which gives the paper a certain degree of permeability to fluids (such as water, oil, ink, juice, etc.). Therefore, the surface of the paper usually needs to be treated to improve its performance. During the papermaking process, the surface of the paper can be treated by applying a sizing agent. Depending on the pH value, sizing agents can be divided into acidic sizing agents, neutral sizing agents and alkaline sizing agents. In recent years, medium-alkaline sizing papermaking has become increasingly popular in the papermaking industry.

[0003] A commonly used neutral sizing agent is alkyl ketene dimer (AKD), which has been used for over 50 years. AKD is a waxy solid at room temperature. AKD can be used as both an internal sizing agent and a surface sizing agent. AKD is typically represented by the following structure:

[0004] Among them, each R a 、R b 、R c and R d The group is independently selected at each occurrence from: hydrogen; optionally substituted, straight or branched C1-C 30 Hydrocarbon. It was found that each R in the above ketene dimer a 、R b 、R c and R d The radicals may be not only saturated hydrocarbon radicals but also unsaturated hydrocarbon radicals (eg alkenyl radicals derived from oleic acid). Ketene dimers with unsaturated hydrocarbon radicals are still referred to as AKD (alkyl ketene dimers) for the sake of convention.

[0005] The four-membered lactone ring in the AKD molecule can react with the hydroxyl groups on cellulose to form an ester bond, thereby being positioned on the cellulose. a 、R b 、R c and R dOne or more of these (in the fiber) creates a hydrophobic effect on the fiber surface and covers part of the pore structure, thereby imparting hydrophobicity and permeability resistance to the paper. The schematic diagram of the reaction between AKD and cellulose is shown below:

[0006] A typical method for preparing AKD involves adding fatty acid chlorides (FACl) and triethylamine (TEA) to a reactor. During this process, the formation of triethylamine hydrochloride (TEA·HCl) as a byproduct increases the viscosity of the reaction, leading to a series of problems such as difficulty in stirring, increased energy consumption, and poor heat dissipation. In many cases, the industry often requires the addition of inert solvents such as toluene to mitigate the adverse effects of high viscosity. With increasing environmental awareness, there is a growing demand for reducing toluene usage.

[0007] One known method of reducing viscosity is to add the residue of an earlier batch of sizing agent (also called HEEL, which includes AKD and TEA·HCl, and optionally unreacted TEA) to the next batch of sizing agent. The HEEL helps to reduce the viscosity of the batch system, but still cannot completely eliminate the use of toluene.

[0008] Currently, there is still a continuous demand in the art for a preparation method of a sizing agent (especially AKD) that can reduce viscosity and a toluene-free preparation method. Summary of the Invention

[0009] Methods for preparing AKD are well known in the art. For example, AKD is typically produced from carboxylic acid compounds via a three-step process of acylation, dehydrochlorination, and dimerization. An exemplary synthesis of AKD is shown below.

[0010] (Reaction 1)

[0011] (Reaction 2)

[0012] (Reaction 3)

[0013] In the AKD shown in structural formula (IV),

[0014] R a The group is independently selected at each occurrence from: hydrogen; optionally substituted, straight or branched C1-C 30 hydrocarbon group;

[0015] R bThe group is independently selected at each occurrence from: hydrogen; optionally substituted, straight or branched C1-C 30 hydrocarbon group;

[0016] R c The group is independently selected at each occurrence from: hydrogen; optionally substituted, straight or branched C1-C 30 a hydrocarbon group; and

[0017] R d The group is independently selected at each occurrence from: hydrogen; optionally substituted, straight or branched C1-C 30 Hydrocarbon group.

[0018] For R a 、R b 、R c or R d Any one of the C1-C 30 The hydrocarbon group is preferably C 10 -C 20 Hydrocarbyl, more preferably C 13 -C 17 Hydrocarbyl, such as C1, C2, C3, C4, C5, C6, C7, C8, C9, C 10 、C 11 、C 12 、C 13 、C 14 、C 15 、C 16 、C 17 、C 18 、C 19 、C 20 、C 21 、C 22 、C 23 、C 24 、C 25 、C 26 、C 27 、C 28 、C 29 、C 30 For R a 、R b 、R c or R d In any of the above, the hydrocarbon group may be an alkyl group, an alkenyl group, or an alkynyl group; preferably, an alkyl group.

[0019] In any of the structural formulas I, II and / or III, the R' group is independently selected at each occurrence from: hydrogen; an optionally substituted, linear or branched C1-C 30 a hydrocarbon group; and / or

[0020] R" groups are independently selected at each occurrence from: hydrogen; optionally substituted, straight or branched C1-C 30 Hydrocarbon group.

[0021] For either R' or R", the C1-C 30 The hydrocarbon group is preferably C 10 -C 20 Hydrocarbyl, more preferably C 13 -C 17 Hydrocarbyl, such as C1, C2, C3, C4, C5, C6, C7, C8, C9, C 10 、C 11 、C 12 、C 13 、C 14 、C 15 、C 16 、C 17 、C 18 、C 19 、C 20 、C 21 、C 22 、C 23 、C 24 、C 25 、C 26 、C 27 、C 28 、C 29 、C 30 For either R' or R", the hydrocarbyl group may be an alkyl group, an alkenyl group, or an alkynyl group; preferably, an alkyl group.

[0022] Formula (III-1) enone is to use enone of formula (III-2) The same steps were used to synthesize R a The group is independently selected at each occurrence from: hydrogen; optionally substituted, straight or branched C1-C 30 Hydrocarbon; R b The group is independently selected at each occurrence from: hydrogen; optionally substituted, straight or branched C1-C 30 Hydrocarbon; R c The group is independently selected at each occurrence from: hydrogen; optionally substituted, straight or branched C1-C 30 Hydrocarbyl; and R d The group is independently selected at each occurrence from: hydrogen; optionally substituted, straight or branched C1-C 30 For R a 、R b 、R c or R d Any one of the C1-C 30 The hydrocarbon group is preferably C10 -C 20 Hydrocarbyl, more preferably C 13 -C 17 Hydrocarbyl, such as C1, C2, C3, C4, C5, C6, C7, C8, C9, C 10 、C 11 、C 12 、C 13 、C 14 、C 15 、C 16 、C 17 、C 18 、C 19 、C 20 、C 21 、C 22 、C 23 、C 24 、C 25 、C 26 、C 27 、C 28 、C 29 、C 30 For R a 、R b 、R c or R d In any of the above, the hydrocarbon group may be an alkyl group, an alkenyl group, or an alkynyl group; preferably, an alkyl group.

[0023] In the acylation step, (a) PCl3, (b) SOCl2, and (c) COCl2 + DMF are three commonly used acylation methods. Method (c) using COCl2 and DMF is currently the most commonly used acylation method, in which phosgene (COCl2) is used as the acylating agent and dimethylformamide (DMF) is used as the catalyst.

[0024] In the dehydrochlorination step, for the purpose of cost saving, triethylamine hydrochloride (N(CH2CH3)3·HCl) is usually regenerated into triethylamine and then recycled.

[0025] In the above reaction 2, the starting materials of formula (II) are generally referred to as fatty acid chlorides (FACl), which undergo dehydrochlorination under the action of triethylamine (TEA). Accordingly, for the purpose of convenience of description only, the starting materials of formula (I) in the above reaction 1 are referred to herein as fatty acids (FA), regardless of whether they are saturated or unsaturated.

[0026] Therefore, a typical step of the AKD preparation method involves contacting TEA and FACl to carry out a reaction, which can also be written as follows: 2FACl + 2TEA → AKD + ​​2TEA·HCl.

[0027] The present invention surprisingly found that by pre-adding the first portion of the total TEA to a HEEL-containing reaction system to obtain a pre-TEA-containing HEEL-containing reaction system, and then adding the remaining second portion of the total TEA and FACl to the pre-TEA-containing HEEL-containing reaction system for reaction, the viscosity of the reaction system can be significantly reduced, allowing the preparation of AKD without solvent (such as toluene). BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG1 shows the viscosity of the reaction systems of Examples 1-4.

[0029] FIG2 shows the viscosity of the reaction systems of Examples 6-8. DETAILED DESCRIPTION

[0030] In some embodiments of the present invention, the present invention provides a method for preparing a sizing agent, comprising the steps of:

[0031] (1) pre-adding a first portion of the total TEA to a HEEL-containing reaction system to obtain a HEEL-containing reaction system pre-added with TEA; and

[0032] (2) adding the remaining second portion of the total TEA and FACl to the HEEL-containing reaction system to which TEA has been pre-added to carry out a reaction;

[0033] The weight percentage of the first part in the total TEA is no more than 90% of the total TEA. The weight percentage of the first part in the total TEA is: 100%×the ratio of the weight of the first part of TEA to the sum of the weight of the first part of TEA and the weight of the remaining second part of TEA.

[0034] In one aspect of the present invention, the HEEL-containing reaction system of the present invention comprises any raw materials / intermediates / products involved in producing the sizing agent, such as FA, TEA, FACl, alkyl ketene, AKD, TEA·HCl, or a combination thereof. In a preferred embodiment, the HEEL-containing reaction system of the present invention comprises FACl, TEA, AKD, TEA·HCl, or a combination thereof.

[0035] In one embodiment, the HEEL described herein is any mixture comprising AKD and TEA·HCl. Optionally, the HEEL further comprises TEA or other components. The HEEL described herein can be fresh or recycled. In one embodiment, the HEEL described herein is part of a reaction mixture from an earlier batch of sizing agent production, which comprises AKD and TEA·HCl, and preferably also comprises unreacted TEA.

[0036] In one embodiment, the AKD and TEA·HCl in the HEEL may be present in any ratio. In one embodiment, the weight ratio of AKD and TEA·HCl is 1:1 to 10:1, preferably 3:1 to 6:1.

[0037] In another embodiment, the AKD, TEA·HCl and TEA (if present) in the HEEL may be present in any ratio. In yet another embodiment, the weight ratio of AKD, TEA·HCl and TEA (if present) is 1:1:5 to 10:1:1, preferably 3:1:1 to 6:1:1.

[0038] In one aspect of the present invention, the reaction mixture of the present invention comprises FA, TEA, FACl, alkyl ketene, AKD, TEA·HCl, or a combination thereof. In one embodiment, the reaction mixture of the present invention is a mixture of the reaction (2FACl+2TEA→AKD+2TEA·HCl).

[0039] In one embodiment, the HEEL-containing reaction system described herein further comprises FA, TEA, FACl, alkyl ketene, AKD, TEA·HCl, or a combination thereof in addition to HEEL. In another embodiment, the HEEL-containing reaction system described herein does not contain other components in addition to HEEL.

[0040] Any of the raw materials described herein, such as FA, TEA, FACl, alkyl ketene, AKD, and / or TEA·HCl, can be either fresh or recycled.

[0041] In one embodiment, the fatty acyl chloride (FACl) described herein is a compound having structural formula (II):

[0042] in,

[0043] The R' group is independently selected at each occurrence from: hydrogen; optionally substituted, straight or branched C1-C 30 a hydrocarbon group; and / or

[0044] R" groups are independently selected at each occurrence from: hydrogen; optionally substituted, straight or branched C1-C 30 Hydrocarbon group.

[0045] For either R' or R", the C1-C 30 The hydrocarbon group is preferably C 10 -C 20 Hydrocarbyl, more preferably C 13 -C 17 Hydrocarbyl, such as C1, C2, C3, C4, C5, C6, C7, C8, C9, C 10 、C 11 、C 12 、C 13 、C 14 、C 15 、C 16 、C 17 、C 18 、C 19 、C 20 、C 21 、C 22 、C 23 、C 24 、C 25 、C 26 、C 27 、C 28 、C 29 、C 30 For either R' or R", the hydrocarbyl group may be an alkyl group, an alkenyl group, or an alkynyl group; preferably, an alkyl group.

[0046] In one aspect of the invention, the fatty acyl chloride (FACl) described herein can be a mixture of two or more fatty acyl chlorides. Similarly, the AKD described herein can be a mixture of two or more AKDs. The fatty acids described herein can be a mixture of two or more fatty acids. The fatty acyl chlorides, fatty acids, and AKD described herein can have the same or different alkyl moieties.

[0047] In one aspect of the invention, the addition (preferably simultaneous addition) of FACl and the second portion of TEA occurs between 50°C and 70°C, such as 51°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, 66°C, 67°C, 68°C, 69°C, 70°C; preferably, between 52°C and 68°C; more preferably, between 52°C and 65°C.

[0048] In one aspect of the invention, the first portion comprises no more than 90% by weight of the total TEA, such as between greater than 0% and 90%, such as 90%, 89%, 88%, 87%, 86%, 85%, 84%, 83%, 82%, 81%, 80%, 79%, 78%, 77%, 76%, 75%, 74%, 73%, 72%, 71%, 70%, 69%, 68%, 67%, 66%, 65%, 64%, 63%, 62%, 61%, 60%, 59%, 58%, 57%, 56%, 55%, 54%, 53%, 52%, 51%, 50%, %, 49%, 48%, 47%, 46%, 45%, 44%, 43%, 42%, 41%, 40%, 39%, 38%, 37%, 36%, 35%, 34%, 33%, 32%, 31%, 30%, 29%, 28%, 27%, 26%, 25%, 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%; or between any two of the above values, preferably between 10% and 90%.

[0049] In a preferred embodiment, the addition (preferably simultaneous addition) of FACl and the second portion of TEA occurs between 52°C and 68°C.

[0050] In one aspect of the invention, the weight percentage of the first portion of TEA is between 10% and 90% of the total TEA. In a preferred embodiment, the addition (preferably simultaneous addition) of FACl and the second portion of TEA in step (2) occurs at a temperature between 52°C and 68°C, more preferably between 52°C and 65°C.

[0051] In one aspect of the invention, FACl and / or the second portion of TEA are added at the same or different rates in step (2). In some embodiments, the rate of addition of FACl is 5 ml / min to 20 ml / min, preferably the rate is 6 ml / min to 16 ml / min. In some embodiments, the rate of addition of TEA is 1 ml / min to 10 ml / min, preferably the rate is 4 ml / min to 8 ml / min.

[0052] In one aspect of the present invention, during the reaction process, the viscosity of the reaction system is less than 250cp, less than 240cp, less than 230cp, less than 220cp, less than 210cp, less than 200cp, less than 190cp, less than 180cp, less than 170cp, less than 160cp, less than 150cp, less than 140cp, less than 130cp, less than 120cp, less than 110cp, less than 100cp, and less than 90cp.

[0053] In one aspect of the present invention, when the reaction process stops, the viscosity of the reaction system is less than 250cp, less than 240cp, less than 230cp, less than 220cp, less than 210cp, less than 200cp, less than 190cp, less than 180cp, less than 170cp, less than 160cp, less than 150cp, less than 140cp, less than 130cp, less than 120cp, less than 110cp, less than 100cp, or less than 90cp.

[0054] In one aspect of the present invention, the ratio of the total moles of the first and second TEA to the moles of FACl is 0.95: 1 to 2: 1, preferably 1.4: 1 to 1.75: 1. In one aspect of the present invention, the ratio of the total weight of the first and second TEA to the weight of FACl is 1: 3 to 2: 3, preferably 1: 1.7 to 1: 2.1.

[0055] The method of the present invention can reduce the viscosity of the reaction mixture. The reduced reaction mixture viscosity reduces the energy consumption required for stirring. At the same time, the reduced reaction mixture viscosity also enables the production of sizing agents (such as AKD) under conditions / operations without solvents such as toluene.

[0056] In one aspect of the present invention, the present invention relates to a method for preparing a sizing agent under toluene-free conditions, comprising the following steps:

[0057] (1) pre-adding a first portion of the total TEA to a HEEL-containing reaction system to obtain a HEEL-containing reaction system pre-added with TEA; and

[0058] (2) adding the remaining second portion of the total TEA and FACl to the HEEL-containing reaction system to which TEA has been pre-added to carry out a reaction;

[0059] The weight percentage of the first part in the total TEA is no more than 90% of the total TEA.

[0060] In one aspect of the present invention, the present invention relates to a method for reducing the viscosity of a sizing agent preparation process (e.g., reducing the viscosity of a reaction mixture), comprising the steps of:

[0061] (1) pre-adding a first portion of the total TEA to a HEEL-containing reaction system to obtain a HEEL-containing reaction system pre-added with TEA; and

[0062] (2) adding the remaining second portion of the total TEA and FACl to the HEEL-containing reaction system to which TEA has been pre-added to carry out a reaction;

[0063] The weight percentage of the first part in the total TEA is no more than 90% of the total TEA.

[0064] As used herein, the term "substituted" means that any one or more hydrogens on the designated atom or group are replaced with a moiety selected from the indicated group, provided that the normal valence of the designated atom is not exceeded.

[0065] "Alkyl" is a branched or straight chain saturated aliphatic hydrocarbon group. In one embodiment, the alkyl group contains 1 to about 20 carbon atoms, more typically 1 to about 12 carbon atoms, 1 to about 6 carbon atoms, or 1 to about 4 carbon atoms. In one embodiment, the alkyl group contains 1 to about 8 carbon atoms. In certain embodiments, the alkyl group is C1-C2, C1-C3, or C1-C6. As used herein, a specified range refers to each member of the range as an independent species of alkyl group. For example, as used herein, the term C1-C 30 Alkyl refers to a straight or branched chain alkyl group having 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 carbon atoms and is intended to refer to each of these as a separate species. For example, as used herein, the term C1-C4 alkyl refers to a straight or branched chain alkyl group having 1, 2, 3 or 4 carbon atoms and is intended to refer to each of these as a separate species. n When alkyl is used in conjunction with another group in this article, for example (C3-C7 cycloalkyl)C0-C4 alkyl or -C0-C4 alkyl(C3-C7 cycloalkyl), the indicated group, in this case cycloalkyl, may be directly bonded by a single covalent bond (C0 alkyl) or connected by an alkyl chain (in this case 1, 2, 3 or 4 carbon atoms). Alkyl may also be connected via other groups such as heteroatoms, as in -O-CO-C4 alkyl(C3-C7 cycloalkyl). Examples of alkyl include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, neopentyl, n-hexyl, 2-methylpentyl, 3-methylpentyl, 2,2-dimethylbutyl and 2,3-dimethylbutyl. In one embodiment, the alkyl group is optionally substituted as described above.

[0066] "Alkenyl" is a branched or straight chain aliphatic hydrocarbon group having one or more carbon-carbon double bonds, which may occur at a stable point along the chain. Non-limiting examples include C2-C8 alkenyl, C2-C6 alkenyl, and C2-C4 alkenyl. As used herein, a specified range refers to each member of the range as an independent species of alkenyl group, as described above for the alkyl portion. For example, as used herein, the term C1-C8 alkenyl, C2-C6 alkenyl, and C2-C4 alkenyl. 30 Alkenyl refers to a straight or branched alkenyl group with 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 carbon atoms and is intended to refer to each of these as an independent species description. The example of alkenyl includes but is not limited to vinyl and propenyl. In one embodiment, the alkenyl group is optionally substituted as described above.

[0067] "Alkynyl" is a branched or straight-chain aliphatic hydrocarbon group having one or more carbon-carbon triple bonds, which may occur at any stable point along the chain, for example, C2-C8 alkynyl or C2-C6 alkynyl. As used herein, a specified range refers to each member of the range as a separate species of alkynyl group, as described above for the alkyl portion. For example, as used herein, the term C1-C8 30 Alkynyl refers to a straight or branched chain alkynyl group with 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 carbon atoms and is intended to refer to each of these as an independent species description. The example of alkynyl includes but is not limited to ethynyl, propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-pentynyl, 2-pentynyl, 3-pentynyl, 4-pentynyl, 1-hexynyl, 2-hexynyl, 3-hexynyl, 4-hexynyl and 5-hexynyl. In one embodiment, alkynyl groups are optionally substituted as described above.

[0068] "Hydrocarbyl" is a branched or straight chain saturated or unsaturated aliphatic group. The hydrocarbyl group may be an alkyl, alkenyl, or alkynyl group. As used herein, a specified range refers to each member of the range as an independent group. For example, as used herein, the term C1-C 30 Hydrocarbyl refers to hydrocarbyl groups having 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 carbon atoms and is intended to refer to each of these being described as a separate species.

[0069] The temperatures described herein are in degrees Celsius. As needed, the concentrations / contents / dosages / portions described herein may be expressed in terms of weight, volume, mole, weight / volume, or volume / weight.

[0070] Adding as used herein refers to adding by any means. The second portion of TEA and FACl herein can be added simultaneously or at different times. The second portion of TEA and FACl herein can be added at the same rate or at different rates.

[0071] Herein, the sum of the first portion TEA and the (remaining) second portion TEA may be referred to as the total TEA. Similarly, the sum of the first portion TEA weight and the (remaining) second portion TEA weight may be referred to as the total TEA weight.

[0072] The total TEA described herein refers to the total amount of TEA to be used, for example, the total amount of TEA to be used calculated based on FACl. Compared to FACl, the amount can be insufficient, equal, or excessive. Those skilled in the art can determine a reasonable total amount of TEA, because the reaction of TEA with FACl to prepare AKD is a reaction known in the art. Typically, those skilled in the art use weight as a unit for feeding and monitoring in this reaction, because the reaction is not actually carried out in a stoichiometric manner.

[0073] Herein, the weight percentage of the first portion TEA is 100% x the ratio of the first portion TEA weight to the sum of the first portion TEA weight and the remaining second portion TEA weight, and may be referred to as an X value or an X range.

[0074] For example, in the present invention, HEEL can be used in an amount of about 5 wt% to 40 wt% of the reaction mixture of an earlier batch of sizing agent production, preferably between 5 wt% and 20 wt%. In one embodiment, the amount of HEEL is 5 wt% to 40 wt% of the total reaction system.

[0075] The process described herein can be carried out in a continuous manner or a batch manner, preferably in a batch manner.

[0076] As used herein, the terms "reaction mixture" and "reaction system" are used interchangeably.

[0077] As used herein, the term "first portion of TEA" refers to the portion of TEA that is intended to be pre-added to the HEEL-containing reaction system.

[0078] The technical solution of the present invention is now described in conjunction with specific examples. It should be understood that the following examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. Unless otherwise stated, the reagents described in this example are all commercially available.

[0079] Specific examples

[0080] Example 1 (control group): without the first part TEA

[0081] Before adding the materials, the reactor was evacuated and nitrogen-purged 2-3 times. 40.6 g of AKD wax powder (n-C16 alkyl AKD:n-C18 alkyl AKD = 60:40 (wt%), Kemira, FennoWax 1840TF) was added to the reactor, stirred, and heated until melted. 10.8 g of triethylamine hydrochloride (99%, Shanghai MacLean Biochemical Technology Co., Ltd.) was then added. After mixing, 405 g of acyl chloride (n-C16 acyl chloride:n-C18 acyl chloride = 60:40 (wt%), Kemira) was added dropwise at a rate of 13.8 ml / min. Simultaneously, 219 g of triethylamine was added dropwise at a rate of 6.8 ml / min. The system temperature was maintained at 60-62°C during the additions. After the additions were completed, the temperature was maintained at 60°C for 1 hour. The viscosity of the reaction system was monitored throughout the reaction using a Heimerson online viscometer (Figure 1). The final viscosity of the system was 973 cP. After separation, a light yellow AKD product is obtained with a purity higher than 85% (in compliance with the implementation standard: GB / T 27565-2011).

[0082] Example 2: The first part of TEA accounts for 70% by weight of TEA

[0083] Before adding the materials, the reactor was evacuated and nitrogen-purged 2-3 times, 40.6 g of AKD wax powder (n-C16 alkyl AKD:n-C18 alkyl AKD = 60:40 (wt%), Kemira, FennoWax1840TF) was added to the reactor, stirred, and heated to melt. Then, 10.8 g of triethylamine hydrochloride (99%, Shanghai McLean Biochemical Technology Co., Ltd.) and 153 g of triethylamine (analytical grade, Shanghai Lingfeng Chemical Reagent Co., Ltd.) were added. After mixing, 400 g of acyl chloride (n-C16 acyl chloride:n-C18 acyl chloride = 60:40 (wt%), Kemira) was added dropwise at a rate of 14.2 ml / min. At the same time, 66 g of triethylamine was added dropwise at a rate of 5.2 ml / min. The system temperature was maintained at 60-62 degrees during the addition. After the addition was completed, the temperature was kept at 60 degrees for 1 hour. The viscosity of the reaction system was monitored throughout the reaction using a Heimerson online viscometer (Figure 1). The final viscosity was 155.1 cP. A pale yellow AKD product was isolated with a purity exceeding 85% (in compliance with GB / T 27565-2011).

[0084] Example 3: The weight ratio of the first part of TEA to the total TEA is 6.4%

[0085] Before adding the materials, the reactor was evacuated and nitrogen-purged 2-3 times. 40.6 g of AKD wax powder (n-C16 alkyl AKD:n-C18 alkyl AKD = 60:40 (wt%), Kemira, FennoWax 1840 TF) was added to the reactor, stirred, and heated until melted. 10.8 g of triethylamine hydrochloride (99%, Shanghai MacLean Biochemical Technology Co., Ltd.) and 14 g of triethylamine (analytical grade, Shanghai Lingfeng Chemical Reagent Co., Ltd.) were then added. After mixing, 400 g of acyl chloride (n-C16 acyl chloride:n-C18 acyl chloride = 60:40 (wt%), Kemira) and 205 g of triethylamine were added dropwise. The system temperature was maintained at 60-62°C during the additions. After completion of the additions, the temperature was maintained at 60°C for 1 hour. The viscosity of the reaction system was monitored throughout the reaction using a Heimerson online viscometer (Figure 1). The final viscosity of the system was 228.3 cP. After separation, a light yellow AKD product is obtained with a purity higher than 85% (in compliance with the implementation standard: GB / T 27565-2011).

[0086] Example 4 (control group): The weight ratio of the first part of TEA to the total TEA is 100%. Before adding the materials, the reactor was vacuumed and replaced with nitrogen 2-3 times, 40.6g of AKD wax powder (n-C16 alkyl AKD:n-C18 alkyl AKD = 60:40 (wt%), Kemira, FennoWax1840TF) was added to the reactor, stirred, and heated to melt. Then, 10.8g of triethylamine hydrochloride (99%, Shanghai MacLean Biochemical Technology Co., Ltd.) and 219g of triethylamine (analytical grade, Shanghai Lingfeng Chemical Reagent Co., Ltd.) were added. After mixing, 400g of acyl chloride (n-C16 acyl chloride:n-C18 acyl chloride = 60:40 (wt%), Kemira) was added dropwise. The system temperature was kept at 60-62 degrees during the addition. After the addition was completed, it was kept warm at 60 degrees for 1 hour. The viscosity of the reaction system was monitored throughout the reaction using a Heimerson online viscometer (Figure 1), with a final viscosity of 715 cP. A pale yellow AKD product with a purity exceeding 85% was obtained after separation (in compliance with GB / T 27565-2011).

[0087] Example 5: The weight ratio of the first portion of TEA to the total TEA (146.1 g) is 1.4%

[0088] Before adding the materials, the reactor was evacuated and nitrogen-purged 2-3 times. 40.6 g of AKD wax powder (n-C16 alkyl AKD:n-C18 alkyl AKD = 5:95 (wt%), Kemira, FennoWax 1895 TFE) was added to the reactor and stirred. The mixture was heated until melted. Then, 10.8 g of triethylamine hydrochloride (99%, Shanghai MacLean Biochemical Technology Co., Ltd.) and 2.1 g of triethylamine (analytical grade, Shanghai Lingfeng Chemical Reagent Co., Ltd.) were added. After mixing, the system temperature was lowered to about 58 degrees. The mixture solidified and stirring was difficult, and the reaction could not be carried out at this temperature.

[0089] Example 6: The weight ratio of the first part of TEA to the total TEA is 21%

[0090] Before adding the materials, the reactor was evacuated and nitrogen-purged 2-3 times. 69.4 g of AKD wax powder (n-C16 alkyl AKD:n-C18 alkyl AKD = 5:95 (wt%), Kemira, FennoWax 1895 TFE) was added to the reactor, stirred, and heated until melted. 35.3 g of triethylamine hydrochloride (99%, Shanghai MacLean Biochemical Technology Co., Ltd.) and 30.8 g of triethylamine (analytical grade, Shanghai Lingfeng Chemical Reagent Co., Ltd.) were then added. After mixing, 405 g of acyl chloride (n-C16 acyl chloride:n-C18 acyl chloride = 5:95 (wt%), Kemira) and 115.3 g of triethylamine were added dropwise. The system temperature was maintained at 58-60°C during the additions. After completion of the additions, the temperature was incubated at 63°C for half an hour. The viscosity of the reaction system was monitored throughout the reaction using a Heimerson online viscometer (Figure 2). The final viscosity of the system was 106.6 cP. After separation, a light yellow AKD product is obtained with a purity higher than 88% (in compliance with the implementation standard: GB / T 27565-2011).

[0091] Example 7: The weight ratio of the first part of TEA to the total TEA is 21%

[0092] Before adding the materials, the reactor was evacuated and nitrogen-purged 2-3 times. 69.4 g of AKD wax powder (n-C16 alkyl AKD:n-C18 alkyl AKD = 5:95 (wt%), Kemira, FennoWax 1895 TFE) was added to the reactor, stirred, and heated until melted. 35.3 g of triethylamine hydrochloride (99%, Shanghai MacLean Biochemical Technology Co., Ltd.) and 30.8 g of triethylamine (analytical grade, Shanghai Lingfeng Chemical Reagent Co., Ltd.) were then added. After mixing, 405 g of acyl chloride (n-C16 acyl chloride:n-C18 acyl chloride = 5:95 (wt%), Kemira) and 115.3 g of triethylamine were added dropwise. The system temperature was maintained at 62-64°C during the additions. After completion of the additions, the temperature was maintained at 63°C for half an hour. The viscosity of the reaction system was monitored throughout the reaction using a Heimerson online viscometer (Figure 2). The final viscosity of the system was 120.5 cP. After separation, a light yellow AKD product is obtained with a purity higher than 88% (in compliance with the implementation standard: GB / T 27565-2011).

[0093] Example 8 (control group): The weight ratio of the first part of TEA to the total TEA is 100%

[0094] Before adding the materials, the reactor was evacuated and nitrogen-purged 2-3 times. 69.4 g of AKD wax powder (n-C16 alkyl AKD:n-C18 alkyl AKD = 5:95 (wt%), Kemira, FennoWax 1895 TFE) was added to the reactor, stirred, and heated until melted. 35.3 g of triethylamine hydrochloride (99%, Shanghai MacLean Biochemical Technology Co., Ltd.) and 146.1 g of triethylamine (analytical grade, Shanghai Lingfeng Chemical Reagent Co., Ltd.) were then added. After mixing, 405 g of acyl chloride (n-C16 acyl chloride:n-C18 acyl chloride = 5:95 (wt%), Kemira) was added dropwise. The system temperature was maintained at 62-64°C during the addition. After completion of the addition, the temperature was maintained at 63°C for half an hour. The viscosity of the reaction system was monitored throughout the reaction using a Heimerson online viscometer (Figure 2). The final viscosity of the system was 262.8 cP. After separation, a light yellow AKD product is obtained with a purity higher than 88% (in compliance with the implementation standard: GB / T 27565-2011).

[0095] The mechanism described in this application description is only for explaining the present invention and is not intended to limit the present invention in any way.

[0096] The foregoing examples and descriptions of embodiments should be considered as illustrative, not limiting, of the invention described herein. The aforementioned specific embodiments are merely specific aspects of the present invention, and the scope of protection of the present invention includes, but is not limited to, the aforementioned specific embodiments. Any embodiment consistent with the scope of the present invention, as well as any appropriate variations or modifications made thereto by a person skilled in the art, shall fall within the scope of protection of the present invention.

[0097] As used herein, the terms "approximately," "about," "substantially," and similar terms are intended to have the broad meanings generally agreed upon and accepted by those skilled in the art for use with the subject matter to which this disclosure pertains. It should be understood by those skilled in the art reading this disclosure that these terms are intended to describe certain features described and claimed without limiting those features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or variations of the subject matter described and claimed are considered to be within the scope of the invention as set forth in the appended claims.

[0098] As used herein, "optional" or "optionally" is intended to indicate that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not. Unless otherwise stated, the indefinite article "a" or "an" and the corresponding definite article "the" as used herein mean at least one, or one or more.

Claims

1. A method for preparing a sizing agent, comprising the following steps: (1) pre-adding the first part of the total TEA to the HEEL-containing reaction system to obtain a HEEL-containing reaction system pre-added with TEA; as well as, (2) adding the remaining second portion of the total TEA and FACl to the HEEL-containing reaction system to which TEA has been pre-added to carry out a reaction; The weight percentage of the first part in the total TEA is not greater than 90% of the total TEA.

2. The method according to claim 1, wherein the addition of the second portion of TEA and FACl in step (2) is carried out between 50°C and 70°C, preferably between 52°C and 68°C.

3. The method according to claim 1 or 2, wherein the weight percentage of the first part to the total TEA is between 10% and 90% of the total TEA.

4. The method according to any one of the preceding claims, wherein step (2) adding the second portion of TEA and FACl is carried out between 52°C and 68°C, and the weight percentage of the first portion in the total TEA is 10% to 90% of the total TEA.

5. The method according to any one of the preceding claims, wherein in step (2) FACl and the second portion of TEA are added at the same or different rates.

6. The method according to claim 5, wherein the rate of adding FACl is 5 ml / min to 20 ml / min, preferably the rate is 6 ml / min to 16 ml / min.

7. The method according to claim 5, wherein the rate of adding the second portion of TEA is 1 ml / min to 10 ml / min, preferably the rate is 4 ml / min to 8 ml / min.

8. The method according to any one of the preceding claims, wherein the ratio of the total weight of the first part of TEA and the second part of TEA to the weight of FACl is 1:3 to 2:3, preferably 1:1.7 to 1:2.

1.

9. A method according to any one of the preceding claims, wherein: The HEEL-containing reaction system further comprises FA, TEA, FACl, alkyl ketene, AKD, TEA·HCl, or a combination thereof in addition to HEEL.

10. The method according to any one of the preceding claims, wherein the sizing agent is alkyl ketene dimer (AKD).

11. The method according to any one of the preceding claims, wherein during the reaction, the viscosity of the reaction system is less than 250 cp, preferably less than 200 cp, more preferably less than 150 cp, most preferably less than 100 cp.

12. The method according to any one of the preceding claims, wherein when the reaction process is stopped, the viscosity of the reaction system is less than 250 cp, preferably less than 200 cp, more preferably less than 150 cp, most preferably less than 100 cp.

Images