Polypropylene hydrophilic adjuvant, its preparation method and application

Abstract

This invention relates to the field of polymer additives technology, and discloses a hydrophilic polypropylene additive, its preparation method, and its application. The hydrophilic polypropylene additive has the following structure: wherein A is any one of carboxyl, hydroxyl, aldehyde, or carbonyl groups; R1 is C4-C6. 11 Straight-chain or branched alkyl groups, where R2 is C5-C 18 The linear or branched alkyl group, R3 being hydrogen or a C1-C6 linear or branched alkyl group, n≥10; the molecular weight of the polypropylene hydrophilic additive is not less than 400. The hydrophilic additive of this invention introduces long-chain alkyl groups and hydrophilic groups. The introduction of hydrophilic groups increases the water absorption rate of the meltblown fabric, while the long-chain alkyl group acts as a compatibilizer, giving the hydrophilic agent good compatibility with the meltblown fabric and making the hydrophilic additive less prone to migration.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polymer additives, in particular to a polypropylene hydrophilic additive, a preparation method and application thereof. BACKGROUND

[0002] Melt-blown cloth generally refers to a melt-blown non-woven fabric prepared by melt-blown technology of high melt index polypropylene, which is stacked by polypropylene fibers. Due to its special structure, the most used is its adsorption function, and it is widely used in air or liquid filtration materials, isolation materials, absorption materials, thermal insulation materials, oil absorption materials, etc., and its downstream products include but are not limited to masks, diapers, sanitary napkins, home decoration cloth, bed covers, industrial cloth, agricultural cloth, etc. However, the unmodified polypropylene non-woven fabric is a hydrophobic material, and the melt-blown cloth needs to have water absorption in the application of diapers, kitchen wipes, sanitary napkins, etc. At present, the most common method for hydrophilic modification of polypropylene melt-blown cloth is to do a layer of hydrophilic coating on the surface through post-processing. Although this method is simple in process and easy to operate, the durability and water washing resistance after treatment are poor, the coating fails after a period of time, and the hydrophilicity is lost, and the price of coating treatment is expensive.

[0003] A more simple method is to do hydrophilic treatment on the material for preparing melt-blown cloth. Generally, a hydrophilic modifier can be used to directly modify the melt-blown material, for example, the currently widely used polypropylene fiber hydrophilic modifier includes Irgasurf HL560, CibaIRGATEC, CR76, etc. Although it improves the hydrophilic property of the melt-blown cloth to a certain extent, it has a great influence on the physical and mechanical properties of the melt-blown cloth. Not only are these hydrophilic modification additives easy to migrate to the surface of the melt-blown cloth, but also the price is relatively expensive.

[0004] CN107245885A discloses a stain-resistant hydrophilic non-woven fabric, which is prepared by treating polypropylene non-woven fabric with polyethylene glycol, lauroyl glutamic acid and humulus liquid at low pressure and constant temperature. It can greatly reduce the surface contact angle of polypropylene non-woven fabric, significantly improve the hydrophilicity of polypropylene non-woven fabric, and also improve the stain resistance of polypropylene non-woven fabric. However, its treatment process is complex, which restricts the production efficiency.

[0005] CN113881134A discloses a composition for hydrophilic non-woven fabric and its application. The main components of the composition include polyvinyl alcohol or polyethylene imine grafted nano-silica composite particles, polyolefin base with a melt flow rate of 10-2000 g / 10 min, antioxidant, acid absorbent, and compatibilizer, etc. The patent improves the hydrophilicity, breaking strength and impact resistance of the non-woven fabric. However, it does not consider the change of hydrophilic efficiency after long-term storage. SUMMARY

[0006] The present application aims at the problem of poor hydrophilicity or unstable hydrophilic assistant of polypropylene non-woven fabric, and provides a polypropylene hydrophilic assistant to replace the traditional hydrophilic assistant, so that the polypropylene becomes a material with hydrophilic property under the premise of maintaining good mechanical property, and the hydrophilic assistant can stably exist in the matrix with remarkable effect.

[0007] To achieve the above object, the technical scheme adopted by the present application is:

[0008] A polypropylene hydrophilic assistant has the following structure:

[0009]

[0010] wherein A is any one of carboxyl, hydroxyl, aldehyde group or carbonyl; R1 is C4-C 11 alkyl, R2 is C5-C 18 alkyl, R3 is hydrogen or C1-C6 linear or branched alkyl, and n≥10; the molecular weight of the polypropylene hydrophilic assistant is not less than 400.

[0011] Preferably, R1 is C4-C 11 alkyl, and R2 is C8-C 18 alkyl. Further, R2 is C 16 or C 18 alkyl.

[0012] The present application also provides a preparation method of the polypropylene hydrophilic assistant, comprising the following steps:

[0013] Step 1: reacting an unsaturated alcohol with part of an epoxy compound under the action of a catalyst to obtain an oligomer; continuing to add the remaining epoxy compound to obtain an unblocked polyether through polymerization reaction;

[0014] Step 2: adjusting the reaction system of step 1 to be alkaline, adding a halogenated alkyl R2X to obtain a crude polyether, and then washing, separating and drying to obtain a blocked polyether product;

[0015] Step 3: oxidizing the blocked polyether product with potassium permanganate, and then washing, separating and drying to obtain the polypropylene hydrophilic assistant;

[0016] The unsaturated alcohol has the following structure:

[0017] R4-OH;

[0018] The epoxy compound has the following structure:

[0019]

[0020] wherein R2, R3 are as defined above, and R4 is C5-C 12 alkene-containing linear or branched hydrocarbon group, and X is halogen, such as chlorine, bromine or iodine.

[0021] The reaction formula of each step in the preparation process is shown as follows:

[0022] Step 1,

[0023]

[0024] Step 2,

[0025] Step 3,

[0026] Preferably, the unsaturated alcohol includes one or more of isopentenol, hexenol, undecenol;

[0027] Preferably, the epoxy compound includes one or more of oxirane, propylene oxide, butylene oxide, 1,2-epoxy pentane, 1,2-epoxy hexane.

[0028] Preferably, the base in Step 1 includes one or more of sodium methoxide, potassium hydroxide, sodium hydroxide, sodium isopentenolate; the amount of the base used is 0.1-0.6% of the mass of the unsaturated alcohol.

[0029] In Step 1, the mass ratio of the unsaturated alcohol to the epoxy compound is 0.2:0.78-0.80; the mass of the epoxy compound added for the first time is 10-20% of the total mass of the epoxy compound, and the mass of the epoxy compound added for the second time is 80-90% of the total mass of the epoxy compound.

[0030] In Step 1, the reaction temperature is 100-150℃.

[0031] In Step 1, the reaction time after the first addition of the epoxy compound is 1-1.5h, and the reaction time after the second addition of the epoxy compound is 1.5-2h.

[0032] Preferably, in Step 1, the reaction is carried out in a high-pressure closed environment, and when the pressure of the reactor is maintained at 0.1-0.3Mpa, the reaction is considered to be completed.

[0033] Preferably, in Step 2, an inorganic base is added to adjust the acidity and alkalinity of the reaction system, and the inorganic base includes one or more of sodium hydroxide, potassium hydroxide, calcium hydroxide; the pH of the reaction system is adjusted to 7-10.

[0034] In Step 2, the end-capping reaction temperature is 150-170℃, and the reaction time is 0.5-1h.

[0035] The molar ratio of the halogenated alkane R2X to the unsaturated alcohol is 1-1.5:1.

[0036] Preferably, the halogenated alkane comprises one or more of bromopentane, bromohexadecane, and bromooctadecane.

[0037] Preferably, the washing and separation of the crude polyether in step 2 specifically comprises: washing the crude polyether with deionized water, and separating the organic phase by standing; adding an acid-base regulator to the organic phase to adjust the pH to neutral, and then dehydrating and filtering to obtain the end-capped polyether product. The acid-base regulator comprises any one of acid clay, citric acid, stone powder, activated carbon, and the like.

[0038] Preferably, in step 3, the reaction is carried out using an aqueous potassium permanganate solution, and the reaction conditions are as follows: an acidic environment, the pH of the reaction environment is 5-6 after adding potassium permanganate, the reaction temperature is 170-190°C, and the reaction time is 0.5-2h.

[0039] The molar ratio of the potassium permanganate to the unsaturated alcohol is 1-1.5:1.

[0040] Preferably, the washing process of the product in step 3 specifically comprises: first, removing the potassium permanganate by filtration, then washing the product with a dilute sodium hydroxide solution, then adding citric acid to adjust the pH to neutral, and finally washing the product with deionized water, dehydrating, and drying to obtain the pure polypropylene hydrophilic aid.

[0041] The application also provides a modified polypropylene, which comprises, in terms of mass fraction, 78.5-98.5 parts of polypropylene, 0-15 parts of nano calcium, and 1-10 parts of the polypropylene hydrophilic aid. Preferably, the modified polypropylene comprises 3-15 parts of nano calcium.

[0042] Preferably, the modified polypropylene further comprises one or more of 0-0.1 parts of a nucleating agent and 0-0.1 parts of an antioxidant, and the respective additive amounts are 0 when not added.

[0043] The antioxidant comprises one or more of antioxidant 1010, antioxidant 168, antioxidant 1098, antioxidant S-9228, and antioxidant 1076.

[0044] The nucleating agent comprises one or more of polyfeng CS-6993, idico NA11, idico NA21, and zhejiang chuangmo NA3011.

[0045] The application is characterized in that long-chain alkyl groups and hydrophilic groups are introduced into the hydrophilic modifier, the introduction of the hydrophilic groups increases the water absorption rate of the melt-blown cloth, and the long-chain alkyl groups act as a compatibilizer, so that the hydrophilic agent has good compatibility with the melt-blown cloth, and the hydrophilic aid is not easy to migrate.

[0046] In the preparation of modified polypropylene, nano calcium is also added in the blending process, so that the void fraction of the non-woven fabric becomes larger, and there is more water storage space. Compared with the current preparation method of hydrophilic melt-blown fabric, not only the hydrophilic performance of polypropylene melt-blown fabric is improved, but also the compatibility of the hydrophilic additive with polypropylene is improved, and the hydrophilic group will not migrate over time, and the good hydrophilic effect can be maintained for a long time.

[0047] Compared with the prior art, the present application has the following beneficial effects:

[0048] (1) The polypropylene hydrophilic additive of the present application has excellent hydrophilic effect, and performs better than the current market hydrophilic agent after being added to the polypropylene matrix.

[0049] (2) The polypropylene hydrophilic additive of the present application has a longer hydrophilic effect, and the hydrophilic performance will not decrease over time. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 The infrared spectrum of the polypropylene hydrophilic additive A3 prepared in Example 3.

[0051] Figure 2 The water contact angle diagram of the water droplets of samples B1, B3 and B6 in Application Example 2.

[0052] Figure 3 The diagram of the change of the water contact angle of the samples with time in Application Example 2. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical scheme and advantages of the present application clearer and more apparent, the present application will be further described in detail below in combination with examples. It should be understood that the specific examples described herein are only used to explain the present application and not to limit the present application. Those skilled in the art can modify or replace equivalently without departing from the spirit and scope of the present application, which should be covered within the protection scope of the present application.

[0054] The sodium hydroxide, prenol, potassium permanganate and halogenated alkyl used in the following examples were purchased from Sinopharm. Other material parameters are as follows:

[0055] Polypropylene: M-1500, melt flow rate 1400-1600 g / 10 min, test conditions 230℃, 2.16 kg, from Hangzhou Fugong New Material Co., Ltd. commercially available product; nucleating agent: CS-6993, from Hangzhou Fugong New Material Co., Ltd. commercially available product.

[0056] The hydrophilic agent is HL560, the antioxidant is 1010 and 168, and the nano calcium is superfine heavy calcium carbonate with a mesh number greater than 3000, all of which are purchased from the market. Other products are not specially described and are all commercially available goods.

[0057] The test method used is:

[0058] (1) Melt index test: Method B of GB / T 3682-2000 is adopted.

[0059] (2) Contact angle test: The static water contact angle is tested according to the standard GB / T 30693-2014 to represent the hydrophilicity, and the profile image method is adopted for analysis. The prepared film is fixed on a flat sample table, then a proper amount of liquid drop is dropped on the surface of the film, and the contact angle is measured.

[0060] (3) Bending performance test: GB / T 1040.1-2008 is adopted.

[0061] (4) Impact performance test: GB / T 1843-2008 is adopted.

[0062] (5) Molecular weight test: GPC gel permeation chromatography of GB / T 27843-2011 is adopted.

[0063] (6) Product structure characterization: Infrared spectrum of GB / T 6040-2002 is adopted.

[0064] Example 1

[0065] A preparation method of a polypropylene hydrophilic modifier comprises the following steps:

[0066] Step 1: 85g of isoamyl alcohol is added to a high-pressure reaction kettle, 0.4g of potassium hydroxide solid is added while stirring, nitrogen replacement is carried out 4 times, heating is started, the temperature is raised to 100℃, then 53.6g of ethylene oxide is slowly introduced into the reactor to induce the reaction, the temperature is gradually raised to 140℃ during the induction process, the temperature is maintained at 140℃, the pressure is maintained relatively constant, and the reaction is carried out for 1h;

[0067] Then 261g of ethylene oxide is added to the reactor, and the temperature is maintained for about 1h. When the pressure of the reactor no longer decreases, the temperature is lowered to 80℃, and after vacuum degassing, the product is discharged.

[0068] Step 2: Sodium hydroxide is added to the product in step 1 to adjust the pH to 9, and then 1mol of bromopentane is further added, and the reaction is carried out at 160℃ for 1h to obtain an unblocked polyether crude product.

[0069] In the capped polyether, 5% of deionized water is added, the temperature is controlled at 68°C, and stirring is carried out at medium speed for 0.5h. The organic phase is separated after standing. Acid clay is added to the organic phase to adjust the pH to neutral, and dehydration is carried out at elevated temperature for 1.5h. The refined capped polyether product is obtained by filtration.

[0070] Step 3: 1 mol of potassium permanganate is added to the refined capped polyether product obtained in Step 2, and the pH of the reaction system is 6. The reaction is carried out at 180°C for 2h. After the reaction is completed, the product, a polypropylene hydrophilic modifier containing hydrophilic groups, is obtained by filtration, washing, separation, and drying. The product is denoted as A1, and the molecular weight of the product is 500, as tested by GPC gel permeation chromatography.

[0071] Example 2

[0072] A method for preparing a polypropylene hydrophilic modifier includes the following steps:

[0073] Step 1: In a high-pressure reaction kettle, 85g of iso-pentenol is added, 0.4g of potassium hydroxide solid is added while stirring, nitrogen replacement is carried out 4 times, heating is started, and the temperature is raised to 100°C. Then, 53.6g of ethylene oxide is slowly introduced into the reactor to induce the reaction. During the induction process, the temperature is gradually raised to 140°C, and the temperature is maintained at 140°C. The pressure is maintained relatively constant, and the reaction is carried out for 1h.

[0074] Then, 261 parts of ethylene oxide are added to the reactor, and the temperature is maintained for about 1h. After the pressure in the reactor no longer decreases, the temperature is reduced to 80°C. After vacuum degassing, the product is discharged.

[0075] Step 2: To the product in Step 1, sodium hydroxide is added to adjust the pH to 9 while stirring. Then, 1 mol of bromohexadecane is added, and the reaction is carried out at 160°C for 1h to obtain a crude un-capped polyether.

[0076] In the capped polyether, 5% of deionized water is added, the temperature is controlled at 68°C, and stirring is carried out at medium speed for 0.5h. The organic phase is separated after standing. Acid clay is added to the organic phase to adjust the pH to neutral, and dehydration is carried out at elevated temperature for 1.5h. The refined capped polyether product is obtained by filtration.

[0077] Step 3: 1 mol of potassium permanganate is added to the refined capped polyether product obtained in Step 2, and the pH of the reaction system is 6. The reaction is carried out at 180°C for 2h. After the reaction is completed, the product, a polypropylene hydrophilic modifier containing hydrophilic groups, is obtained by filtration, washing, separation, and drying. The product is denoted as A2, and the molecular weight of the product is 600, as tested by GPC gel permeation chromatography.

[0078] Example 3

[0079] A method for preparing a polypropylene hydrophilic modifier includes the following steps:

[0080] Step 1, 85 g of iso-pentenyl alcohol was added into a high-pressure reactor, 0.4 g of potassium hydroxide was added while stirring, nitrogen was replaced for 4 times, heating was started, the temperature was raised to 100°C, then 53.6 g of ethylene oxide was slowly introduced into the reactor to induce the reaction, the temperature was gradually raised to 140°C during the induction, the temperature was maintained at 140°C, the pressure was maintained relatively constant, and the reaction was carried out for 1 h;

[0081] Then 261 parts of ethylene oxide was added into the reactor, and the temperature was maintained for about 1 h, then the temperature was lowered to 80°C, the reactor was degassed by vacuum, and the product was discharged.

[0082] Step 2, sodium hydroxide was added into the product of step 1 to adjust the pH to 9, and 1 mol of bromohexadecane was further added, and the reaction was carried out at 160°C for 1 h to obtain a crude unblocked polyether product;

[0083] 5% deionized water was added into the blocked polyether, the temperature was controlled at 68°C, and the organic phase was separated after stirring at medium speed for 0.5 h; acid clay was added into the organic phase to adjust the pH to neutral, and the product was obtained by dehydration at elevated temperature for 1.5 h and filtration.

[0084] Step 3, 1 mol of potassium permanganate was added into the refined blocked polyether product obtained in step 2, and the reaction was carried out at 180°C for 2 h, and the pH of the reaction was 6. After the reaction was completed, the product was obtained by filtration, washing, separation, and drying, and the product was a polypropylene hydrophilic agent containing hydrophilic groups, which was denoted as A3. The product was tested by GPC gel permeation chromatography, and the molecular weight was 700. The product structure was analyzed by infrared spectrogram, and the specific structure was shown in Figure 1 The spectrogram showed that the absorption peaks of C-O-C were at 1090 cm -1 and 1150 cm -1 The absorption peaks of -CH2 and -CH3 were at 2882 cm -1 and 2994 cm -1 The obvious absorption peak of -COOH was at 2324 cm -1 .

[0085] Application Example

[0086] Step 1, M1500, superfine heavy calcium carbonate, the hydrophilic agent prepared in examples 1-3, antioxidant tetra-β(3,5-di-tert-butyl-4-hydroxyphenyl propionic acid) pentaerythritol (1010), antioxidant tris(2,4-di-tert-butyl) phenyl phosphite (168), and nucleating agent CS-6993 were uniformly mixed in a high-speed mixer, and the ratio of each component was shown in Table 1.

[0087] Step 2, extruding the mixture of step 1 on a twin-screw extruder, the length-diameter ratio of the twin-screw extruder used is 60, the number of segments is 14, the temperature settings of each segment of the extruder are: 175℃ for the first segment, 175℃ for the second segment, 195℃ for the third segment, 215℃ for the fourth segment, 235℃ for the fifth segment, 255℃ for the sixth segment, 255℃ for the seventh segment, 235℃ for the eighth segment, 215℃ for the ninth segment, 205℃ for the tenth segment, 195℃ for the eleventh segment, 185℃ for the twelfth segment, 175℃ for the thirteenth segment, 175℃ for the fourteenth segment, the rotation speed of the extruder is 400r / min, and the high-melt-index polypropylene particles with hydrophilic properties are obtained after cooling and granulation.

[0088] Table 1: Application Example Components Raw Material Mass Parts Ratio

[0089]

[0090] The polypropylene samples obtained according to the above test scheme are tested for melt index, and then the samples are pressed into 0.5mm-thick films for testing of contact angle. The experimental results are shown in Table 2, from which it can be seen that after the addition of the hydrophilic modification aid, the contact angle of the sample is significantly smaller, and the hydrophilicity is significantly improved. Specifically, B1, B3 and B6 are placed under a high-magnification high-speed camera to capture the whole process of water droplets dropping onto the fiber surface, and the whole process of the water droplets changing from small to large and spreading on the fiber surface is recorded, as shown in Figure 2 Table 2. At the same time, the mechanical properties are also improved to a certain extent. The melt index test conditions are 230℃ and 2.16kg.

[0091] Table 2: Performance of Each Application Example

[0092]

[0093] The sample prepared in Application Example 1 is placed at 23℃ and 50% RH for 10 days, and water contact angle testing is performed every day, and the results are shown in Figure 3 Table 3. The water contact angle test results of B1, B3, B4, B5 and B6 every day after 10 days of placement are compared, and it can be seen from the figure that the water contact angle of B3 and B4 gradually increases with time, which is because the hydrophilic agent migrates with time. The contact angles of B5 and B6 do not change much, which is because A2 and A3 hydrophilic agents have long-chain alkanes, which have strong affinity with the polypropylene matrix and are not prone to migration.

Claims

1. A polypropylene hydrophilic aid, characterized in that, has the following structure: wherein A is any of a carboxyl group, a hydroxyl group or an aldehyde group; R1is a C4-C 11 straight or branched chain alkyl group, R2is a C8-C 18 straight or branched chain alkyl group, R3is hydrogen or a C1-C6straight or branched chain alkyl group, and n > 10; the molecular weight of the polypropylene hydrophilic adjuvant is not less than 400.

2. The method for preparing the polypropylene hydrophilic additive according to claim 1, characterized in that, comprising the steps of: Step 1, reacting unsaturated alcohol with part of the epoxy compound under the catalysis of base to obtain oligomer; continue to add the rest of the epoxy compound, and polymerization reaction obtains unblocked polyether; Step 2, adjusting the reaction system of Step 1 to alkaline, adding halogenated alkane R2X to block the end to obtain crude polyether, and washing, separating and drying to obtain blocked polyether product; Step 3, carrying out oxidation reaction of the blocked polyether product with potassium permanganate, and washing, separating and drying the product to obtain the polypropylene hydrophilic agent; The unsaturated alcohol has the following structure: R4-OH; The epoxy compound has the following structure: wherein R2, R3 are as defined in claim 1, and R4 is C5-C 12 alkenyl-containing linear or branched hydrocarbon group, and X is halogen.

3. The method for preparing the polypropylene hydrophilic additive according to claim 2, characterized in that, The unsaturated alcohol includes one or more of isopentenol, hexenol and undecenol; And / or, the epoxy compound includes one or more of oxirane, propylene oxide, butylene oxide, 1,2-epoxy pentane and 1,2-epoxy hexane.

4. The method for preparing the polypropylene hydrophilic additive according to claim 2, characterized in that, The base in Step 1 includes one or more of sodium methoxide, potassium hydroxide, sodium hydroxide and sodium isopentenolate; the amount of the base used is 0.1-0.6% of the mass of the unsaturated alcohol; In Step 1, the mass ratio of the unsaturated alcohol to the total epoxy compound is 0.2:0.78-0.80; the mass of the first added epoxy compound is 10-20% of the mass of the total epoxy compound, and the mass of the second added epoxy compound is 80-90% of the mass of the total epoxy compound; The reaction temperature in Step 1 is 100-150℃; The reaction time after the first addition of the epoxy compound in Step 1 is 1-1.5h; and the reaction time after the second addition of the epoxy compound is 1.5-2h.

5. The method for preparing the polypropylene hydrophilic additive according to claim 2, characterized in that, In Step 2, an inorganic base is added to adjust the acidity and alkalinity of the reaction system, and the inorganic base includes one or more of sodium hydroxide, potassium hydroxide and calcium hydroxide; the pH of the reaction system is adjusted to 7-10; The end-blocking reaction temperature in Step 2 is 150-170℃, and the reaction time is 0.5-1h; The molar ratio of the halogenated alkane R2X to the unsaturated alcohol is 1-1.5:

1.

6. The method for preparing the polypropylene hydrophilic additive according to claim 2, characterized in that, The halogenated alkane includes one or more of bromohexadecane and bromooctadecane.

7. The method for preparing the polypropylene hydrophilic additive according to claim 2, characterized in that, In Step 3, an aqueous solution of potassium permanganate is used for reaction, and the reaction conditions are an acidic environment, the pH of the reaction environment is 5-6, the reaction temperature is 170-190℃, and the reaction time is 0.5-2h; The molar ratio of the potassium permanganate to the unsaturated alcohol is 1-1.5:

1.

8. A modified polypropylene characterized in that, According to the mass fraction, the raw materials include 78.5-98.5 parts of polypropylene, 0-15 parts of nano calcium and 1-10 parts of the polypropylene hydrophilic agent of claim 1.

9. The modified polypropylene according to claim 8, characterized in that, It also includes one or more of 0-0.1 parts of nucleating agent and 0-0.1 parts of antioxidant, and each additive is 0 when the additive amount is different.

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