Compound surfactant and preparation method thereof

Abstract

The invention relates to a compound surfactant and a preparation method thereof. The compound surfactant is prepared from the following components in parts by weight: 40 to 70 parts of a nonionic surfactant and 20 to 30 parts of an anionic surfactant. The invention discloses a preparation method of a compound surfactant. The preparation method comprises the following steps: S1, respectively carrying out dehydration treatment on a formula amount of polymeric monomer, a formula amount of catalyst and a formula amount of initiator; s2, adding the catalyst and the initiator dehydrated in the step S1 into a reaction kettle, adding the polymeric monomer dehydrated in the step S1 in batches, and reacting in a nitrogen atmosphere to obtain a nonionic surfactant; and S3, uniformly mixing the anionic surfactant with the formula ratio with the nonionic surfactant obtained in the step S2 to obtain the compound surfactant. The method has the following beneficial effects: 1, the reaction efficiency is high; 2, the molecular weight distribution of the product can be well reduced;

Description

Technical Field

[0001] The invention relates to the technical field of surfactants, and in particular to a compound surfactant and a preparation method thereof. Background Art

[0002] Since the advent of polyether polyols in the 1930s, they were first used as non-ionic surfactants. In the following decades, polyether polyols have developed extremely rapidly. At present, the global annual production capacity of polyether polyols has reached millions of tons, and its application areas are constantly expanding and becoming more and more important. Only a very small amount needs to be added during product processing or manufacturing, and using one or several of its functions can produce huge effects and benefits.

[0003] Chinese invention patent CN103846082B discloses a mesoporous carbon composite metal oxide as a basic solid catalyst, which has a two-dimensional hexagonal mesoscopic structure, a large specific surface area and a uniform pore size distribution. It is used to catalyze ethoxylation reactions. Compared with traditional ethoxylation catalysts with strong bases, it has the advantages of narrow product distribution, high reaction conversion rate and selectivity, and easy post-treatment. However, the technical solution of the above patent still has the following shortcomings: it can only catalyze the ethoxylation reaction of low-carbon alcohols with a carbon number of less than 4, and the product is only fatty alcohol monoether, which has a narrow application range.

[0004] Chinese invention patent application CN109369903A discloses using Zr oxide as a catalyst carrier, then adding a co-catalyst, and finally loading an alkali metal. This method can prepare fatty alcohol polyethers with narrow distribution, low raw material residue, and low PEG / PPG content. However, the technical solution of the above patent still has the following shortcomings: the loading of the alkali metal on the catalyst carrier adopts an impregnation method, which increases the post-processing step. At the same time, since the catalyst has only a surface layer, the activity of the catalyst will decrease sharply with the number of uses.

[0005] Currently, the surfactants on the market are mainly fatty alcohol polyoxyethylene ethers. This type of product has good comprehensive properties such as diffusion, leveling, wetting, and foaming. However, strong base catalysts are used in the preparation process, which has disadvantages such as poor flow properties, uneven diffusion, and a narrow range of use. Summary of the invention

[0006] Purpose of the invention: In view of the above-mentioned deficiencies in the prior art, the present invention provides a compound surfactant and a preparation method thereof. The present invention selects long-chain polyhydric fatty alcohols as initiators, ethylene oxide and propylene oxide as reaction monomers, prepares a nonionic surfactant with narrow molecular weight distribution and high surface activity, and compounds it with anionic surfactants in a specific ratio to further enhance the emulsification performance of the surfactant.

[0007] Technical solution: A compound surfactant, composed of the following components by weight: 40-70 parts of nonionic surfactant, 20-30 parts of anionic surfactant, preferably 40-60 parts of nonionic surfactant, 20-25 parts of anionic surfactant.

[0008] Furthermore, the anionic surfactant is at least one of ammonium stearate, sodium stearate, sodium n-dodecyl sulfonate (CAS: 2386-53-0), sodium alkyl aryl sulfonate, and sodium alkyl sulfate.

[0009] Furthermore, the anionic surfactant is a mixture of sodium n-dodecyl sulfate and ammonium stearate, and the weight ratio of sodium n-dodecyl sulfate to ammonium stearate is 1:(2-5), preferably 1:2.5.

[0010] Furthermore, the sodium alkyl aryl sulfonate is one of C10-C18 sodium benzene sulfonate or C10-C18 sodium naphthalene sulfonate.

[0011] Furthermore, the alkyl sodium sulfate is one of sodium dodecyl sulfate, sodium tridecyl sulfate, sodium tetradecyl sulfate and sodium pentadecyl sulfate.

[0012] Furthermore, the nonionic surfactant is composed of the following components: an initiator, a polymerization monomer, and a catalyst, wherein:

[0013] The molar ratio of the initiator to the polymerization monomer is 1:(40-60), preferably 1:45;

[0014] In terms of mass percentage, the catalyst accounts for 0.1-0.5wt% of the total weight of the polymerized monomers, preferably 0.15-0.4wt%, and most preferably 0.18wt%.

[0015] Furthermore, the initiator is at least one of dodecanediol (CAS: 5675-51-4), 1,14-tetradecanediol, 1,16-hexadecanediol, and 1,18-octadecanediol (CAS: 3155-43-9).

[0016] Furthermore, the initiator is a mixture of dodecanediol and 1,18-octadecanediol, and the weight ratio of dodecanediol to 1,18-octadecanediol is 1:(1-3), preferably 1:3.

[0017] Furthermore, the catalyst is a double metal cyanide catalyst purchased from Shanghai Qike Fluorosilicon Materials Co., Ltd., model: DMC-001.

[0018] Furthermore, the polymerizable monomers are ethylene oxide and propylene oxide, and the molar ratio of ethylene oxide to propylene oxide is 1:(0.05-0.2), preferably 1:0.1.

[0019] A method for preparing the above-mentioned composite surfactant comprises the following steps:

[0020] S1, dehydrating the formulated amount of polymerization monomer, the formulated amount of catalyst, and the formulated amount of initiator respectively;

[0021] S2, adding the catalyst and initiator dehydrated in step S1 into a reaction kettle, adding the polymerization monomer dehydrated in step S1 in batches, and reacting under a nitrogen atmosphere to obtain a nonionic surfactant;

[0022] S3, uniformly mixing the anionic surfactant in the formula amount with the nonionic surfactant obtained in step S2 to obtain a composite surfactant.

[0023] Furthermore, in step S2, the catalyst and initiator dehydrated in step S1 are added to the reactor, and 30-40 wt% of the polymerized monomer dehydrated in step S1 is added first, and the first reaction is carried out under a nitrogen atmosphere. When the pressure rises to 0.8-1.2 MPa, the remaining polymerized monomer dehydrated in step S1 is added to continue the second reaction for 1-2 hours to obtain a nonionic surfactant.

[0024] Furthermore, the reaction temperature of the first reaction in step S2 is 80-115°C, preferably 90-100°C.

[0025] Furthermore, the reaction temperature of the second reaction in step S2 is 110-145°C, preferably 120-135°C, most preferably 128°C;

[0026] The reaction pressure of the second reaction in step S2 is 0.5-1.5 MPa, preferably 1-1.5 MPa, most preferably 1.05 MPa.

[0027] Beneficial effects: The composite surfactant and the preparation method thereof disclosed in the present invention have the following beneficial effects:

[0028] 1. High reaction efficiency - the molar ratio of the initiator to the polymerization monomer is controlled to be 1: (40-60), the reaction temperature of the second reaction is controlled to be 110-145°C, and the pressure of the second reaction is controlled to be 0.5-1.5MPa, which can greatly improve the reaction efficiency.

[0029] 2. It can effectively reduce the molecular weight distribution of the product - by first adding 30-40wt% of the polymerization monomer, reacting under a nitrogen atmosphere, and when the pressure rises to 0.8-1.2MPa, adding the remaining polymerization monomer can effectively reduce the molecular weight distribution of the product. Specific implementation method:

[0030] The specific embodiments of the present invention are described in detail below.

[0031] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0032] The inventors found that when the molar ratio of the initiator to the polymerization monomer is 1: (40-60), the reaction efficiency can be improved. As the amount of polymerization monomer increases, the highest temperature reached in the reactor is higher; the lower the induction period temperature, the shorter the induction time, and the faster the reaction. The reason is: at higher temperatures, the more polymerization monomers there are, the more gas molecules there are per unit volume, so the contact probability between the monomers and the initiator molecules per unit volume is greater. When the molecules absorb energy and transform from normal molecules to activated molecules, the effective collisions between the molecules will increase, so the reaction occurs in a short time. Once the reaction occurs, the heat released will further intensify the reaction, and the reaction can be completed quickly. Because the more molecules participating in the reaction per unit time, the more violent the reaction, and the more heat released, when the temperature is too high, it can neither further increase the reaction rate nor improve the product quality, but instead lead to an increase in by-products and a waste of resources. At the same time, too high a temperature will also cause safety problems.

[0033] The inventors found that when the temperature of the second reaction is 110-145°C and the pressure of the second reaction is 0.5-1.5MPa, the reaction efficiency can be improved. At a lower temperature, the reaction duration is longer and the maximum pressure reached is also smaller. As the temperature increases, the maximum pressure in the reactor increases continuously. This is because in a relatively low temperature and limited space, a small portion of liquid propylene oxide is not converted into a gaseous state, and the pressure at this time is relatively small; as the temperature increases, this small portion of liquid propylene oxide begins to convert into a gaseous state, and the pressure begins to increase. Since the amount of propylene oxide is constant, the pressure has a maximum value. When the temperature reaches 128°C, the induction time of the reaction is the shortest and the reaction is the fastest. This is because at this temperature, the gas pressure in the reaction system is in a suitable range, and it is easier for molecules to collide effectively, so the reaction can be activated in a shorter time, and the reaction proceeds quickly. Further research found that adding polymerization monomers in batches can reduce the molecular weight distribution of the product, which may be to control the temperature of the reaction system to rise steadily and remain near 128°C for a long time.

[0034] Example 1

[0035] A compound surfactant comprises, by weight, 50 parts of a nonionic surfactant and 22 parts of an anionic surfactant.

[0036] Furthermore, the anionic surfactant is a mixture of sodium n-dodecyl sulfonate (CAS: 2386-53-0) and ammonium stearate, and the weight ratio of the sodium alkyl sulfonate to the ammonium stearate is 1:2.5.

[0037] The nonionic surfactant is composed of an initiator, a polymerization monomer and a catalyst, wherein:

[0038] The molar ratio of the initiator to the polymerization monomer is 1:45;

[0039] In terms of mass percentage, the catalyst accounts for 0.18 wt % of the polymerization monomers.

[0040] The initiator is a mixture of dodecanediol and 1,18-octadecanediol, and the weight ratio of the dodecanediol (CAS: 5675-51-4) to the 1,18-octadecanediol (CAS: 3155-43-9) is 1:3.

[0041] The catalyst is a double metal cyanide catalyst purchased from Shanghai Qike Fluorosilicon Materials Co., Ltd., model: DMC-001.

[0042] The polymerization monomer is a mixture of ethylene oxide and propylene oxide, and the molar ratio of the ethylene oxide to the propylene oxide is 1:0.1.

[0043] A method for preparing the above-mentioned composite surfactant comprises the following steps:

[0044] S1, dehydrating a formulated amount of polymerization monomer, a formulated amount of catalyst, and a formulated amount of initiator respectively;

[0045] S2, adding the catalyst and initiator after the dehydration treatment in step S1 into the reactor, first adding 35wt% of the polymerization monomer, and carrying out the first reaction under a nitrogen atmosphere. When the pressure of the reactor rises to 0.8MPa, adding the remaining polymerization monomer and continuing the second reaction for 1.5h to obtain a nonionic surfactant;

[0046] S3, uniformly mixing the anionic surfactant in the formula amount with the nonionic surfactant obtained in step S2 to obtain a composite surfactant.

[0047] Furthermore, in step S2, the reaction temperature of the first reaction is 95°C.

[0048] Furthermore, the reaction temperature of the second reaction in step S2 is 128° C.; the reaction pressure of the second reaction in step S2 is 1.05 MPa.

[0049] Example 2

[0050] It is substantially the same as Example 1, except that the molar ratio of the initiator to the polymerization monomer is 1:50.

[0051] Example 3

[0052] It is roughly the same as Example 1, except that the specific process parameters of the preparation method are different:

[0053] A method for preparing the above-mentioned composite surfactant comprises the following steps:

[0054] S1, dehydrating a formulated amount of polymerization monomer, a formulated amount of catalyst, and a formulated amount of initiator respectively;

[0055] S2, adding the catalyst and initiator after the dehydration treatment in step S1 into the reactor, first adding 40wt% of the polymerization monomer, and carrying out the first reaction under a nitrogen atmosphere. When the pressure of the reactor rises to 0.8MPa, adding the remaining polymerization monomer and continuing the second reaction for 1h to obtain a nonionic surfactant;

[0056] S3, uniformly mixing the anionic surfactant in the formula amount with the nonionic surfactant obtained in step S2 to obtain a composite surfactant.

[0057] Example 4

[0058] A compound surfactant consists of the following components by weight: 40 parts of nonionic surfactant and 20 parts of anionic surfactant.

[0059] Furthermore, the anionic surfactant is ammonium stearate.

[0060] Furthermore, the nonionic surfactant is composed of the following components: an initiator, a polymerization monomer, and a catalyst, wherein:

[0061] The molar ratio of the initiator to the polymerization monomer is 1:40;

[0062] In terms of mass percentage, the catalyst accounts for 0.1 of the total weight of the polymerization monomers.

[0063] In another embodiment, the nonionic surfactant is composed of the following components: an initiator, a polymerization monomer, and a catalyst, wherein:

[0064] The molar ratio of the initiator to the polymerization monomer is 1:40;

[0065] In terms of mass percentage, the catalyst accounts for 0.15 of the total weight of the polymerization monomers.

[0066] Furthermore, the initiator is dodecanediol (CAS: 5675-51-4).

[0067] Furthermore, the catalyst is a double metal cyanide catalyst purchased from Shanghai Qike Fluorosilicon Materials Co., Ltd., model: DMC-001.

[0068] Furthermore, the polymerization monomers are ethylene oxide and propylene oxide, and the molar ratio of ethylene oxide to propylene oxide is 1:0.05.

[0069] A method for preparing the above-mentioned composite surfactant comprises the following steps:

[0070] S1, dehydrating the formulated amount of polymerization monomer, the formulated amount of catalyst, and the formulated amount of initiator respectively;

[0071] S2, adding the catalyst and initiator dehydrated in step S1 into a reaction kettle, adding the polymerization monomer dehydrated in step S1 in batches, and reacting under a nitrogen atmosphere to obtain a nonionic surfactant;

[0072] S3, uniformly mixing the anionic surfactant in the formula amount with the nonionic surfactant obtained in step S2 to obtain a composite surfactant.

[0073] Furthermore, in step S2, the catalyst and initiator dehydrated in step S1 are added to the reactor, and 30 wt% of the polymerized monomer dehydrated in step S1 is added first, and the first reaction is carried out under a nitrogen atmosphere. When the pressure rises to 0.8 MPa, the remaining polymerized monomer dehydrated in step S1 is added to continue the second reaction for 2 hours to obtain a nonionic surfactant.

[0074] Furthermore, the reaction temperature of the first reaction in step S2 is 80°C.

[0075] In another embodiment, the reaction temperature of the first reaction in step S2 is 90°C.

[0076] Furthermore, the reaction temperature of the second reaction in step S2 is 110° C., and the reaction pressure of the second reaction in step S2 is 0.5 MPa.

[0077] In another embodiment, the reaction temperature of the second reaction in step S2 is 120° C., and the reaction pressure of the second reaction in step S2 is 1 MPa.

[0078] Example 5

[0079] A compound surfactant consists of the following components in parts by weight: 70 parts of nonionic surfactant and 30 parts of anionic surfactant.

[0080] In another embodiment, a compound surfactant is composed of the following components, by weight: 60 parts of nonionic surfactant and 25 parts of anionic surfactant.

[0081] Furthermore, the anionic surfactant is sodium stearate.

[0082] Furthermore, the nonionic surfactant is composed of the following components: an initiator, a polymerization monomer, and a catalyst, wherein:

[0083] The molar ratio of the initiator to the polymerization monomer is 1:60;

[0084] In terms of mass percentage, the catalyst accounts for 0.5wt% of the total weight of the polymerization monomers.

[0085] In another embodiment, the nonionic surfactant is composed of the following components: an initiator, a polymerization monomer, and a catalyst, wherein:

[0086] The molar ratio of the initiator to the polymerization monomer is 1:60;

[0087] In terms of mass percentage, the catalyst accounts for 0.4 wt % of the total weight of the polymerization monomers.

[0088] Furthermore, the initiator is 1,14-tetradecanediol.

[0089] Furthermore, the catalyst is a double metal cyanide catalyst purchased from Shanghai Qike Fluorosilicon Materials Co., Ltd., model: DMC-001.

[0090] Furthermore, the polymerization monomers are ethylene oxide and propylene oxide, and the molar ratio of ethylene oxide to propylene oxide is 1:0.2.

[0091] A method for preparing the above-mentioned composite surfactant comprises the following steps:

[0092] S1, dehydrating the formulated amount of polymerization monomer, the formulated amount of catalyst, and the formulated amount of initiator respectively;

[0093] S2, adding the catalyst and initiator dehydrated in step S1 into a reaction kettle, adding the polymerization monomer dehydrated in step S1 in batches, and reacting under a nitrogen atmosphere to obtain a nonionic surfactant;

[0094] S3, uniformly mixing the anionic surfactant in the formula amount with the nonionic surfactant obtained in step S2 to obtain a composite surfactant.

[0095] Furthermore, in step S2, the catalyst and initiator dehydrated in step S1 are added to the reactor, and 40 wt% of the polymerized monomer dehydrated in step S1 is added first, and the first reaction is carried out under a nitrogen atmosphere. When the pressure rises to 1.2 MPa, the remaining polymerized monomer dehydrated in step S1 is added to continue the second reaction for 1 hour to obtain a nonionic surfactant.

[0096] Furthermore, the reaction temperature of the first reaction in step S2 is 115°C.

[0097] In another embodiment, the reaction temperature of the first reaction in step S2 is 100°C.

[0098] Furthermore, the reaction temperature of the second reaction in step S2 is 145° C., and the reaction pressure of the second reaction in step S2 is 1.5 MPa.

[0099] In another embodiment, the reaction temperature of the second reaction in step S2 is 135° C., and the reaction pressure of the second reaction in step S2 is 1.5 MPa.

[0100] Example 6

[0101] A compound surfactant consists of the following components in parts by weight: 46 parts of nonionic surfactant and 23 parts of anionic surfactant.

[0102] Furthermore, the anionic surfactant is sodium n-dodecyl sulfate (CAS: 2386-53-0).

[0103] Furthermore, the nonionic surfactant is composed of the following components: an initiator, a polymerization monomer, and a catalyst, wherein:

[0104] The molar ratio of the initiator to the polymerization monomer is 1:45;

[0105] In terms of mass percentage, the catalyst accounts for 0.18 wt % of the total weight of the polymerization monomers.

[0106] Furthermore, the initiator is 1,16-hexadecanediol.

[0107] Furthermore, the catalyst is a double metal cyanide catalyst purchased from Shanghai Qike Fluorosilicon Materials Co., Ltd., model: DMC-001.

[0108] Furthermore, the polymerization monomers are ethylene oxide and propylene oxide, and the molar ratio of ethylene oxide to propylene oxide is 1:0.1.

[0109] A method for preparing the above-mentioned composite surfactant comprises the following steps:

[0110] S1, dehydrating the formulated amount of polymerization monomer, the formulated amount of catalyst, and the formulated amount of initiator respectively;

[0111] S2, adding the catalyst and initiator dehydrated in step S1 into a reaction kettle, adding the polymerization monomer dehydrated in step S1 in batches, and reacting under a nitrogen atmosphere to obtain a nonionic surfactant;

[0112] S3, uniformly mixing the anionic surfactant in the formula amount with the nonionic surfactant obtained in step S2 to obtain a composite surfactant.

[0113] Furthermore, in step S2, the catalyst and initiator dehydrated in step S1 are added to the reactor, and 35 wt% of the polymerized monomer dehydrated in step S1 is added first, and the first reaction is carried out under a nitrogen atmosphere. When the pressure rises to 1 MPa, the remaining polymerized monomer dehydrated in step S1 is added to continue the second reaction for 1.5 hours to obtain a nonionic surfactant.

[0114] Furthermore, the reaction temperature of the first reaction in step S2 is 95°C.

[0115] Furthermore, the reaction temperature of the second reaction in step S2 is 128°C.

[0116] The reaction pressure of the second reaction in step S2 is 1.05 MPa.

[0117] Example 7-31

[0118] It is roughly the same as Example 4, except that the anionic surfactant is different:

[0119]

[0120]

[0121] Examples 32-37 are substantially the same as Example 4, except that the initiators are different:

[0122]

[0123] Comparative Example 1

[0124] It is substantially the same as Example 1, except that the molar ratio of the initiator to the polymerization monomer is 1:30.

[0125] Comparative Example 2

[0126] It is substantially the same as Example 1, except that the reaction temperature of the second reaction is 110° C. and the reaction pressure of the second reaction is 0.7 MPa.

[0127] Comparative Example 3

[0128] It is roughly the same as Example 1, except that the specific process parameters of the preparation method are different:

[0129] A method for preparing the above-mentioned composite surfactant comprises the following steps:

[0130] S1, dehydrating the formulated amount of polymerization monomer, the formulated amount of catalyst, and the formulated amount of initiator respectively;

[0131] S2, adding the catalyst, initiator and polymerization monomer after the dehydration treatment in step S1 into a reaction kettle, reacting under a nitrogen atmosphere and a pressure of 1.05 MPa, with a reaction temperature of 128° C. and a reaction time of 1.5 h, and obtaining a nonionic surfactant after the reaction is completed;

[0132] S3, uniformly mixing the anionic surfactant in the formula amount with the nonionic surfactant obtained in step S2 to obtain a composite surfactant.

[0133] Performance Testing Methods

[0134] 1) The nonionic surfactants prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to GPC (gel permeation chromatography) test for molecular weight distribution. The test data are listed in Table 1.

[0135] 2) The surface activity of the composite surfactants prepared in Examples 1-3 and Comparative Examples 1-3 was tested by a pull-off method to measure the surface tension of their aqueous solutions. The test data are listed in Table 1.

[0136] Performance test data

[0137] Table 1

[0138] Molecular weight distribution Surface tension mN / m Example 1 1.12 20.5 Example 2 1.13 21.6 Example 3 1.16 21.4 Comparative Example 1 1.31 27.1 Comparative Example 2 1.29 26.5 Comparative Example 3 1.34 26.5

[0139] From Table 1, it can be seen that the surface tension of Examples 1-3 is reduced by about 25% relative to that of Control Examples 1-3, and the molecular weight distribution of the products of Examples 1-3 is also greatly reduced relative to that of Control Examples 1-3.

[0140] The above describes the embodiments of the present invention in detail. However, the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A composite surfactant, characterized in that: The invention is composed of the following components by weight: 40-70 parts of nonionic surfactant and 20-30 parts of anionic surfactant, preferably 40-60 parts of nonionic surfactant and 20-25 parts of anionic surfactant.

2. A composite surfactant as claimed in claim 1, characterized in that: The anionic surfactant is at least one of ammonium stearate, sodium stearate, sodium n-dodecyl sulfonate, sodium alkyl aryl sulfonate and sodium alkyl sulfate.

3. A composite surfactant as claimed in claim 2, characterized in that, The anionic surfactant is a mixture of sodium n-dodecyl sulfate and ammonium stearate, and the weight ratio of the sodium n-dodecyl sulfate to the ammonium stearate is 1:(2-5), preferably 1:2.

5.

4. A composite surfactant as claimed in claim 1, characterized in that: The sodium alkyl aryl sulfonate is one of C10-C18 sodium benzene sulfonate or C10-C18 sodium naphthalene sulfonate.

5. A composite surfactant as claimed in claim 1, characterized in that: The alkyl sodium sulfate is one of sodium dodecyl sulfate, sodium tridecyl sulfate, sodium tetradecyl sulfate and sodium pentadecyl sulfate.

6. A composite surfactant as claimed in claim 1, characterized in that, The nonionic surfactant is composed of the following components: an initiator, a polymerization monomer, and a catalyst, wherein: The molar ratio of the initiator to the polymerization monomer is 1:(40-60), preferably 1:45; In terms of mass percentage, the catalyst accounts for 0.1-0.5wt% of the total weight of the polymerized monomers, preferably 0.15-0.4wt%, and most preferably 0.18wt%.

7. A composite surfactant as claimed in claim 1, characterized in that, The initiator is at least one of dodecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol and 1,18-octadecanediol.

8. A composite surfactant as claimed in claim 7, characterized in that: The initiator is a mixture of dodecanediol and 1,18-octadecanediol, and the weight ratio of the dodecanediol to the 1,18-octadecanediol is 1:(1-3), preferably 1:

3.

9. A composite surfactant as claimed in claim 1, characterized in that, The catalyst is a double metal cyanide catalyst.

10. A composite surfactant according to claim 1, characterized in that: The polymerizable monomers are ethylene oxide and propylene oxide, and the molar ratio of ethylene oxide to propylene oxide is 1:(0.05-0.2), preferably 1:0.

1.

11. A method for preparing the composite surfactant according to any one of claims 1 to 10, characterized in that: The following steps are involved: S1, dehydrating the formulated amount of polymerization monomer, the formulated amount of catalyst, and the formulated amount of initiator respectively; S2, adding the catalyst and initiator dehydrated in step S1 into a reaction kettle, adding the polymerization monomer dehydrated in step S1 in batches, and reacting under a nitrogen atmosphere to obtain a nonionic surfactant; S3, uniformly mixing the anionic surfactant in the formula amount with the nonionic surfactant obtained in step S2 to obtain a composite surfactant.

12. The method for preparing the composite surfactant according to claim 11, characterized in that: In step S2: The catalyst and initiator dehydrated in step S1 are added to the reactor, and 30-40 wt% of the polymerized monomer dehydrated in step S1 is added first, and the first reaction is carried out under a nitrogen atmosphere. When the pressure rises to 0.8-1.2 MPa, the remaining polymerized monomer dehydrated in step S1 is added to continue the second reaction for 1-2 hours to obtain a nonionic surfactant.

13. The method for preparing the composite surfactant according to claim 12, characterized in that: The reaction temperature of the first reaction in step S2 is 80-115°C, preferably 90-100°C.

14. The method for preparing the composite surfactant according to claim 13, characterized in that: The reaction temperature of the second reaction in step S2 is 110-145°C, preferably 120-135°C, most preferably 128°C; The reaction pressure of the second reaction in step S2 is 0.5-1.5 MPa, preferably 1-1.5 MPa, most preferably 1.05 MPa.

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