Bio-based PUR (Polyurethane) hot melt adhesive for summer fabric lamination as well as preparation method and application thereof

Abstract

The invention relates to a bio-based PUR (Polyurethane) hot melt adhesive for summer fabric lamination as well as a preparation method and application thereof. The raw materials of the hot melt adhesive comprise the following components in parts by mass: 40 to 60 parts of bio-based polyether polyol, 30 to 40 parts of bio-based polyester polyol, 20 to 25 parts of aliphatic diisocyanate, 0.5 to 1.5 parts of an amine catalyst, 1 to 5 parts of a mosquito-repelling microcapsule, 1 to 5 parts of a reaction-promoting control compound and 0.3 to 1 part of an antioxidant, the mosquito-repelling microcapsule comprises an essential oil core material and a wall material, wherein the mass ratio of the essential oil core material to the wall material is (0.5-1): 1; the reaction-promoting control compound comprises an amine reaction-promoting agent and a porous adsorption material, and the mass ratio of the amine reaction-promoting agent to the porous adsorption material is (0.2-0.6): 1. Compared with the prior art, the high-bio-based mosquito-repellent adhesive has the advantages of high bio-based content, excellent skin-friendly property, smooth and firm fitting, washing resistance and long-acting mosquito-repellent function.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polyurethane hot melt adhesive, and relates to a bio-based PUR hot melt adhesive for summer fabric bonding, a preparation method and application thereof. BACKGROUND

[0002] PUR hot melt adhesive, also known as moisture curing reaction type polyurethane hot melt adhesive, has a significant advantage in the bonding field due to its dual curing mechanism of physical wetting and chemical moisture curing crosslinking. It is in a solid state at room temperature, and after heating, it is coated on the surface of the substrate in the form of a molten fluid. First, it quickly locates through wetting, and then the isocyanate groups (-NCO) in the adhesive layer react with moisture in the air and active groups such as hydroxyl groups on the surface of the substrate, gradually forming three-dimensional crosslinking structures such as urea bonds and urethane bonds, and finally curing into a tough and flexible adhesive film, allowing the substrate to form a high-strength and durable bond. It has excellent temperature resistance, bonding strength, chemical corrosion resistance and aging resistance, and is widely used in the fields of textiles, packaging, woodworking, automobiles and electronic processing.

[0003] The traditional petroleum-based polyurethane hot melt adhesive has the following problems: first, its raw materials are not renewable, which does not meet the trend of environmental protection and sustainable development; second, the traditional adhesive has insufficient flexibility, and the hand feeling after bonding is stiff, which affects the skin-friendly comfort of summer clothing; third, it has poor hydrolysis resistance and is prone to delamination after repeated washing. In summary, it is difficult to meet the basic properties of summer fabrics, such as lightness, breathability and skin-friendliness.

[0004] In addition, existing hot melt adhesives for textiles have single functions and cannot meet the demand for mosquito repellency during summer outdoor activities. Although some studies have attempted to add mosquito-repelling ingredients to hot melt adhesives, direct addition of plant essential oils will volatilize and lose effectiveness during high-temperature processing, and cannot achieve long-lasting mosquito-repelling effects.

[0005] Patent CN120505066A discloses a high-temperature resistant moisture curing polyurethane hot melt adhesive, a preparation method and application thereof. The preparation raw materials of the high-temperature resistant moisture curing polyurethane hot melt adhesive include the following components in weight percentage: bio-based polyol 20-50 parts; polyether polyol 180-450 parts; polyester polyol 200-450 parts; isocyanate 120-200 parts; tackifying resin 80-150 parts; catalyst 0.1-0.5 parts. Although this patent uses bio-based polyol to replace petroleum-based materials, aiming to improve the initial adhesion strength and high-temperature resistance, it does not optimize the skin-friendliness and wash-resistant stability of summer fabrics during bonding, and the application range is limited. SUMMARY

[0006] The present application aims to overcome at least one of the defects of the prior art, and provides a summer fabric-fitting bio-based PUR hot melt adhesive, a preparation method and application thereof.

[0007] The object of the present application can be achieved by the following technical solutions:

[0008] One of the technical solutions of the present application is to provide a summer fabric-fitting bio-based PUR hot melt adhesive, the raw materials of the hot melt adhesive include the following components by mass fraction: bio-based polyether polyol 40-60 parts, bio-based polyester polyol 30-40 parts, aliphatic diisocyanate 20-25 parts, amine catalyst 0.5-1.5 parts, mosquito-repelling microcapsule 1-5 parts, reaction-promoting control compound 1-5 parts, and antioxidant 0.3-1 part;

[0009] The mosquito-repelling microcapsule includes essential oil core material and wall material, and the mass ratio of the essential oil core material to the wall material is (0.5-1):1;

[0010] The reaction-promoting control compound includes amine reaction-promoting agent and porous adsorbent material, and the mass ratio of the amine reaction-promoting agent to the porous adsorbent material is (0.2-0.6):1.

[0011] Further, the essential oil core material is selected from one or more of eucalyptus oil, peppermint oil, hyssop oil, cedar oil, catnip oil, citronella oil, camphor oil, and lavender oil, and the wall material is melamine-modified urea-formaldehyde resin.

[0012] The amine reaction-promoting agent is selected from one or more of triethylamine, methyldiethanolamine, N -methylmorpholine, choline, and one or more tertiary / quaternary amines, and the porous adsorbent material is selected from one or more of diatomite, white carbon black, and activated carbon.

[0013] Further, the raw materials of the mosquito-repelling microcapsule include essential oil core material emulsion and wall material solution, the raw materials of the essential oil core material emulsion include essential oil core material, surfactant, polyvinyl alcohol, and water, and the mass ratio of the essential oil core material, surfactant, polyvinyl alcohol, and water is (0.5-1):(0.01-0.1):(0.01-0.05):(5-10), the raw materials of the wall material solution include wall material and water, the volume ratio of water in the wall material solution is 50-75%, and the raw materials of the melamine-modified urea-formaldehyde resin include formaldehyde, urea, and melamine, and the molar ratio of the formaldehyde, urea, and melamine is (5-10):(1-5):(0.5-1.5).

[0014] The average particle size of the mosquito-repelling microcapsule is 2-5 μm.

[0015] Preferably, the surfactant is Tween 80.

[0016] Further, the preparation method of the mosquito-repelling microcapsule comprises the following steps:

[0017] S3.1, mixing the essential oil core material, the surfactant, the polyvinyl alcohol and water, homogenizing to obtain a core material emulsion;

[0018] S3.2, mixing the formaldehyde, the urea and the melamine uniformly, adjusting the pH, increasing the temperature, forming a melamine-modified urea-formaldehyde resin prepolymer, diluting with water to obtain a wall material solution;

[0019] S3.3, adding the wall material solution dropwise into the core material emulsion, adjusting the pH after the addition is completed, and reacting;

[0020] S3.4, adjusting the pH after the reaction is completed, cooling, filtering, washing, and drying to obtain the mosquito-repelling microcapsule;

[0021] In step S3.1, the rotation speed for homogenization is 3000-4000 rpm, and the time is 1-10 min;

[0022] In step S3.2, triethanolamine is used to adjust the pH to 8.0-8.5, the temperature for increasing the temperature is 70-75 ℃, and the holding time is 1-3 h;

[0023] In step S3.3, the addition speed is 0.5-1.5 mL / min, formic acid solution is used to adjust the pH to 4.0-4.5 after the addition is completed, the reaction temperature is 65-75 ℃, the stirring speed is 1500-2500 rpm, and the time is 2-4 h;

[0024] In step S3.4, ammonia water is used to adjust the pH to 7.0-7.5 after the reaction is completed.

[0025] Preferably, in the preparation process of the mosquito-repelling microcapsule, the concentration of the formic acid solution is 1-10%, and the concentration of the ammonia water is 10-30%.

[0026] Further, the bio-based polyether polyol is a castor oil-based polyether polyol, and the raw materials of the castor oil-based polyether polyol include castor oil, formic acid, hydrogen peroxide, a DMC catalyst, a mixed monomer of propylene oxide and epoxycyclohexane, an antioxidant and carbodiimide, and the mass ratio of the castor oil, the formic acid, the hydrogen peroxide, the DMC catalyst, the propylene oxide, the epoxycyclohexane, the antioxidant and the carbodiimide is (50-150):(1-10):(10-30):(0.5-1.5):(50-250):(50-250):(0.1-1):(0.1-1);

[0027] The number average molecular weight of the castor oil-based polyether polyol is 1000-2500, and the hydroxyl value is 75-150 mg KOH / g.

[0028] As a preferred technical solution, in the raw material of the castor oil-based polyether polyol, the concentration of hydrogen peroxide is 20-40%, and the antioxidant is selected from one or more of 2,6-di-tert-butyl-4-methylphenol, tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester, eucommia leaf extract, tannic acid, tea polyphenol, grape seed extract, curcumin, glycyrrhizin.

[0029] Further, the preparation method of the castor oil-based polyether polyol comprises the following steps:

[0030] S2.1, mixing castor oil and formic acid, adding hydrogen peroxide, neutralizing, filtering and dehydrating to obtain epoxidized castor oil;

[0031] S2.2, adding DMC catalyst, vacuum dehydrating, adding mixed monomers of propylene oxide and cyclohexene oxide, and reacting;

[0032] S2.3, vacuum removing unreacted monomers, adding antioxidant and carbodiimide, mixing, filtering to obtain castor oil-based polyether polyol;

[0033] In step S2.2, the temperature of vacuum dehydration is 100-120℃, the vacuum degree is ≤-0.09 MPa, and the time is 20-40 min,

[0034] The temperature of the reaction is 110-120℃, and the time is 3-5 h;

[0035] In step S2.3, the mixing time is 1-3 h.

[0036] As a preferred technical solution, in step S2.3, the temperature of vacuum removing unreacted monomers is 100-120℃, the vacuum degree is ≤-0.09 MPa, and the time is 20-40 min.

[0037] Further, the bio-based polyester polyol is selected from one or more of castor oil polyester polyol, bio-based polyethylene glycol adipate diol, and bio-based polycarbonate diol;

[0038] The aliphatic diisocyanate is selected from one or more of isophorone diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate;

[0039] The amine catalyst is selected from one or more of dimorpholinyl diethyl ether, triethylenediamine, and dimethyl ethanolamine tertiary amine;

[0040] The antioxidant is selected from one or more of 2,6-di-tert-butyl-4-methylphenol, tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] pentaerythritol ester, eucommia leaf extract, tannic acid, tea polyphenol, grape seed extract, curcumin, glycyrrhizin.

[0041] One of the technical solutions of the present application is to provide a preparation method of the summer fabric-adhering bio-based PUR hot melt adhesive, which comprises the following steps:

[0042] S1.1, vacuum dehydration of bio-based polyether polyol, bio-based polyester polyol and antioxidant;

[0043] S1.2, adding aliphatic diisocyanate under a protective gas atmosphere, mixing to form a polyurethane prepolymer, adding an amine catalyst, and reacting;

[0044] S1.3, adding a reaction-promoting control compound and mosquito-repelling microcapsules, and mixing to uniformly disperse them;

[0045] S1.4, stopping heating, discharging under a protective gas atmosphere, and obtaining summer fabric-adhering bio-based PUR hot melt adhesive, which is sealed and stored.

[0046] Further, the temperature for vacuum dehydration in step S1.1 is 100-120 DEG C, the vacuum degree is less than or equal to -0.09 MPa, and the time is 1-3 h;

[0047] In step S1.2, the temperature for adding aliphatic diisocyanate under a protective gas atmosphere is 75-85 DEG C,

[0048] The temperature for mixing is 80-90 DEG C, and the time is 2-3 h,

[0049] The temperature for reaction is 80-90 DEG C, and the time is 30-60 min;

[0050] In step S1.3, the temperature for adding a reaction-promoting control compound and mosquito-repelling microcapsules is 65-70 DEG C,

[0051] The mixing time is 1-2 h.

[0052] As a preferred technical solution, the protective gas in steps S1.2 and S1.4 is nitrogen.

[0053] One of the technical solutions of the present application is to provide a summer fabric-adhering bio-based PUR hot melt adhesive for use in summer clothing fabric.

[0054] Compared with the prior art, the present application has the following beneficial effects:

[0055] (1) The raw material of the application adopts bio-based polyether polyol and bio-based polyester polyol, the core material of the mosquito repellent microcapsule adopts natural essential oil, and the antioxidant can also adopt renewable resources such as eucommia leaf extract and tea polyphenol, so the bio-based content is high, the dependence on petroleum resources is reduced, and the green and environmentally friendly trend is met;

[0056] (2) The application has high colloidal softness by matching a high proportion of polyether polyol and aliphatic diisocyanate, and the amine catalyst system is used to reduce the irritation index and improve the biocompatibility, so that there is no stiffness after pasting, the skin-friendly high comfort requirement of summer light and thin fabric is met, and the washing resistance is excellent, and the good bonding strength is still maintained after multiple washing;

[0057] (3) The application adopts a reaction-promoting control compound system, which can absorb the intermediate product carbon dioxide (CO2) generated by the wet curing reaction of isocyanate groups (-NCO) and water, the amine reaction promoter can react with carbon dioxide, and the porous adsorption material can adsorb carbon dioxide, so as to promote the movement of the wet curing reaction balance, realize rapid curing and balance of eliminating bubbles, and achieve smooth and firm pasting; The porous adsorption material in the application has three functions of adsorbing carbon dioxide, carrying amine reaction promoter, amine catalyst and mosquito repellent microcapsule as a carrier, and stabilizing the microcapsule, so as to improve the dispersion uniformity and stability of each component of the product;

[0058] (4) The application adopts essential oil microcapsulation technology, the wall material of the core-shell structure resists high temperature during the preparation of hot melt adhesive, avoids the volatilization and failure of essential oil core material, protects the stability of essential oil core material in the processing process, and enhances the washing resistance, so that the components are not easy to break and lose during washing; The application can promote the slow rupture of the wall material in the process of daily fabric friction, release the essential oil core material to effectively realize long-acting mosquito repellent, and provide additional functions for summer clothes. DETAILED DESCRIPTION

[0059] The application will be described in detail below in combination with specific embodiments. The embodiments are implemented on the premise of the technical scheme of the application, and detailed implementation modes and specific operation processes are given, but the protection scope of the application is not limited to the following examples.

[0060] The equipment used in the following examples is conventional in the art unless otherwise specified; the reagents used are commercially available or prepared by conventional methods in the art unless otherwise specified, and the following examples are implemented by conventional experimental means in the art.

[0061] The following operation steps are generally carried out at room temperature and atmospheric pressure unless otherwise emphasized.

[0062] In the following examples, the castor oil-based polyether polyol and its preparation method have the following specific steps:

[0063] S2.1, mix 100 parts of castor oil and 5 parts of formic acid, slowly drop 20 parts of 30% hydrogen peroxide, neutralize, filter and dehydrate to obtain epoxidized castor oil;

[0064] S2.2, add 1 part of DMC catalyst, vacuum dehydrate at 110 ℃, -0.095 MPa for 30 min, add 150 parts of propylene oxide and 150 parts of mixed monomers of epoxy cyclohexane, react at 115 ℃ for 4 h;

[0065] S2.3, vacuum remove unreacted monomers at 110 ℃, -0.095 MPa for 30 min, add 0.5 parts of tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester and 0.5 parts of carbodiimide, stir for 2 h, filter to obtain castor oil-based polyether polyol with a number average molecular weight of 1500 and a hydroxyl value of 112 mg KOH / g.

[0066] Example 1:

[0067] A bio-based PUR hot melt adhesive for summer fabric bonding, the specific components of the raw materials are as follows in parts by mass:

[0068] Castor oil-based polyether polyol 50 parts, bio-based polyester polyol (castor oil polyester polyol, Shanghai Shuxu SY760) 35 parts, aliphatic diisocyanate (isophorone diisocyanate, Wanhua Chemical WANNATE IPDI) 22 parts, amine catalyst (triethylenediamine) 1 part, mosquito-repelling microcapsule 3 parts, reaction-promoting control compound 5 parts (triethylamine 1.5 parts and diatomite 3.5 parts), antioxidant 0.5 parts (tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester 0.3 parts and eucommia leaf extract 0.2 parts);

[0069] Among them, the specific steps of the preparation method of the mosquito-repelling microcapsule are as follows:

[0070] S3.1, mix essential oil core material, Tween 80, polyvinyl alcohol and deionized water according to a mass ratio of 0.8:0.05:0.03:8, wherein the essential oil core material includes 4 parts of peppermint oil, 3 parts of hyssop oil and 1 part of camphor oil, homogenize at 3500 rpm for 5 min to obtain a core material emulsion;

[0071] S3.2, uniformly mix formaldehyde, urea and melamine according to a molar ratio of 7:4:1, adjust the pH to 8.2 using triethanolamine, heat to 72 ℃, and keep the temperature for 2 h to form a melamine-modified urea-formaldehyde resin prepolymer, dilute the prepolymer with deionized water by three times to obtain a wall material solution;

[0072] S3.3, drop the wall material solution into the core material emulsion at a speed of 1 mL / min, the mass ratio of essential oil core material to wall material is 0.8:1, after the drop is completed, use 5% formic acid solution to adjust the pH to 4.2, react at 70 ℃, 2000 rpm for 3 h;

[0073] S3.4, after the reaction is completed, use 20% ammonia water to adjust the pH to 7.2, cool, filter, wash, dry, and obtain mosquito-repellent microcapsules with an average particle size of 3 μm.

[0074] The preparation method of the bio-based PUR hot melt adhesive for summer fabric bonding is as follows:

[0075] S1, vacuum dehydration of castor oil-based polyether polyol, bio-based polyester polyol and antioxidant at 110 ℃, -0.095 MPa for 2 h;

[0076] S2, cool to 80 ℃, slowly add aliphatic diisocyanate under nitrogen protection, stir at 85 ℃ for 2.5 h to form a polyurethane prepolymer; add amine catalyst and continue to react at 85 ℃ for 48 min;

[0077] S3, cool to 68 ℃, add reaction promoting control compound and mosquito-repellent microcapsules, stir for 1.5 h to make them uniformly dispersed;

[0078] S4, stop heating, discharge under nitrogen protection to obtain the bio-based PUR hot melt adhesive for summer fabric bonding, and seal for storage.

[0079] Example 2:

[0080] A bio-based PUR hot melt adhesive for summer fabric bonding, the specific components of the raw materials are as follows in mass fraction:

[0081] Castor oil-based polyether polyol 45 parts, bio-based polyester polyol (bio-based polyethylene glycol adipate diol, Benoke Technology XCP-355) 38 parts, aliphatic diisocyanate (isophorone diisocyanate, Wanhua Chemical WANNATE IPDI) 23 parts, amine catalyst (dimorpholinyl diethyl ether) 1.5 parts, mosquito-repellent microcapsules 4 parts, reaction promoting control compound 4 parts (methyl diethanolamine 1.3 parts and white carbon black 2.7 parts), antioxidant 0.8 parts (tea polyphenol 0.5 parts and glycyrrhizin 0.3 parts);

[0082] Among them, the mosquito-repellent microcapsules and the preparation method thereof are basically the same as those in Example 1, except that the essential oil core material in step S3.2 includes 4 parts of peppermint oil, 3 parts of catnip oil and 1 part of camphor oil, the mass ratio of essential oil core material to wall material in step S3.3 is 0.6:1, and finally the mosquito-repellent microcapsules with an average particle size of 2 μm are obtained.

[0083] The preparation method of the bio-based PUR hot melt adhesive for summer fabric bonding is the same as that in Example 1.

[0084] Example 3

[0085] A bio-based PUR hot melt adhesive for summer fabric bonding, the specific components of the raw materials are as follows in mass fraction:

[0086] Castor oil-based polyether polyol 55 parts, bio-based polyester polyol (bio-based polyethylene glycol adipate diol 14 parts, Benoke Technology XCP-355, bio-based polycarbonate diol 18 parts, Yuanli Chemical BIO-PCDL) 32 parts, aliphatic diisocyanate (4,4'-dicyclohexyl methane diisocyanate, Wanhua Chemical WANNATE HMDI) 24 parts, amine catalyst (triethylenediamine) 0.5 parts, mosquito repellent microcapsule 5 parts, reaction promoting control compound 4 parts (triethylamine 1 part and activated carbon 3 parts), antioxidant 0.7 parts (grape seed extract 0.3 parts and tannic acid 0.4 parts);

[0087] Among them, the mosquito repellent microcapsule and its preparation method are basically the same as those in Example 1, except that the essential oil core material in step S3.2 includes 5.33 parts of citronella oil and 2.67 parts of eucalyptus oil, and the mass ratio of the essential oil core material to the wall material in step S3.3 is 0.8:1, and finally the mosquito repellent microcapsule with an average particle size of 4 μm is obtained.

[0088] The preparation method of the bio-based PUR hot melt adhesive for summer fabric bonding is the same as that in Example 1.

[0089] Example 4

[0090] A bio-based PUR hot melt adhesive for summer fabric bonding, the specific components of the raw materials are as follows in mass fraction:

[0091] Castor oil-based polyether polyol 55 parts, bio-based polyester polyol (bio-based polyethylene glycol adipate diol 14 parts, Benoke Technology XCP-355, bio-based polycarbonate diol 18 parts, Yuanli Chemical BIO-PCDL) 32 parts, aliphatic diisocyanate (4,4'-dicyclohexyl methane diisocyanate, Wanhua Chemical WANNATE HMDI) 24 parts, amine catalyst (triethylenediamine) 0.5 parts, mosquito repellent microcapsule 5 parts, reaction promoting control compound 4 parts (triethylamine 1 part and activated carbon 3 parts), antioxidant 0.7 parts (grape seed extract 0.3 parts and tannic acid 0.4 parts); N - methylmorpholine 1.3 parts and diatomite 2.7 parts), antioxidant 0.6 parts (tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester 0.3 parts and tannic acid 0.3 parts);

[0092] Among them, the mosquito repellent microcapsule and its preparation method are basically the same as those in Example 1, except that the essential oil core material in step S3.2 includes 5.33 parts of citronella oil and 2.67 parts of eucalyptus oil, and the mass ratio of the essential oil core material to the wall material in step S3.3 is 0.8:1, and finally the mosquito repellent microcapsule with an average particle size of 4 μm is obtained.

[0093] The preparation method of the bio-based PUR hot melt adhesive for summer fabric bonding is the same as that of Example 1.

[0094] Example 5:

[0095] A bio-based PUR hot melt adhesive for summer fabric bonding, the specific components of the raw materials are as follows in mass fraction:

[0096] 60 parts of castor oil-based polyether polyol, 30 parts of bio-based polyester polyol (bio-based polyethylene glycol adipate diol, Benoke Technology XCP-355), 25 parts of aliphatic diisocyanate (isophorone diisocyanate, Wanhua Chemical WANNATE IPDI), 1.5 parts of amine catalyst (dimorpholinyl diethyl ether), 4 parts of mosquito repellent microcapsule, 5 parts of reaction promoting control compound (1.6 parts of triethylamine and 3.4 parts of white carbon black), 1 part of antioxidant (0.3 parts of 2,6-di-tert-butyl-4-methylphenol and 0.7 parts of curcumin);

[0097] Among them, the mosquito repellent microcapsule and its preparation method are basically the same as those of Example 1, except that the essential oil core material in step S3.2 includes 3.2 parts of catmint oil, 3.2 parts of citronella oil and 1.6 parts of eucalyptus oil, and the mass ratio of the essential oil core material to the wall material in step S3.3 is 0.8:1, and finally the mosquito repellent microcapsule with an average particle size of 2 μm is obtained.

[0098] The preparation method of the bio-based PUR hot melt adhesive for summer fabric bonding is the same as that of Example 1.

[0099] Comparative Example 1:

[0100] A bio-based PUR hot melt adhesive and its preparation method are basically the same as those of Example 1, except that no reaction promoting control compound is added.

[0101] Comparative Example 2:

[0102] A bio-based PUR hot melt adhesive and its preparation method are basically the same as those of Example 1, except that no porous adsorbent material (diatomite) in the reaction promoting control compound is added.

[0103] Comparative Example 3:

[0104] A bio-based PUR hot melt adhesive and its preparation method are basically the same as those of Example 1, except that no mosquito repellent microcapsule is added.

[0105] Comparative Example 4:

[0106] A bio-based PUR hot melt adhesive and a preparation method thereof, which are substantially the same as those in Example 1, except that the aliphatic diisocyanate is replaced by diphenylmethane diisocyanate instead of isophorone diisocyanate.

[0107] The above bio-based PUR hot melt adhesive is directly applied in summer clothing fabrics.

[0108] The above PUR hot melt adhesive is subjected to the following detection or test, and then the detection or test results are analyzed.

[0109] Test example:

[0110] The above PUR hot melt adhesive is subjected to performance tests, and the performance test results are shown in Table 1, and the specific steps are as follows:

[0111] 1. Peel strength, prepare 75Dx75D, 240T polyester cloth, waterproof and moisture permeable film, and polyester floating yarn as the adherend, uniformly coated with hot melt adhesive, and placed for 1 h and 48 h after ironing and pressing, and then the peel strength of the PUR hot melt adhesive is determined by using an electronic universal testing machine according to GB / T 2791-1995;

[0112] 2. Anti-mosquito effect, the mosquito repellent rate is evaluated according to GB / T 30126-2013 "Determination and evaluation of anti-mosquito performance of textiles", certain aggressive mosquitoes are placed in a space with a fabric sample, the sample is attached to the human body, the number of mosquitoes stopping on the surface of the test sample and the control sample within a specified time is counted, and the anti-mosquito performance of the PUR hot melt adhesive is evaluated by the mosquito repellent rate;

[0113] 3. Water washing resistance, prepare 75Dx75D, 240T polyester cloth, waterproof and moisture permeable film, and polyester floating yarn as the adherend, uniformly coated with hot melt adhesive, and placed for 48 h after ironing and pressing, and then the peel strength and mosquito repellent rate of the PUR hot melt adhesive are determined by using a type A standard washing machine 4N program according to GB / T 8629-2017, selecting standard detergent 3 as the detergent, and taking out the test sample after 50 times of washing;

[0114] 4. Softness, prepare a polyester cloth sample coated with hot melt adhesive, test the Shore hardness of the PUR hot melt adhesive by a Shore hardness tester; select 10 testers to test the hand feeling of the polyester cloth sample after curing and placing for 72 h, and evaluate the average value according to the grade evaluation of FZ / T01166-2022, the higher the grade, the better the skin-friendly performance; and the softness of the PUR hot melt adhesive is evaluated by combining the Shore hardness and the grade evaluation.

[0115] Table 1 Performance test results in examples and comparative examples

[0116] As shown in Table 1, the peel strength of the PUR hot melt adhesive in Examples 1 to 5 remains at a high level before and after 50 times of water washing, and the mosquito repellent rate is maintained above 60% before and after water washing, indicating that the PUR hot melt adhesive in the examples has good adhesion, wash resistance and long-term mosquito repellent stability; the peel strength of the PUR hot melt adhesive in Examples 1 to 5 is above 5N after 1h, indicating that the PUR hot melt adhesive in the examples is not prone to produce bubbles during bonding, and has good flatness and use effect; it can be seen from the Shore hardness and subjective skin-friendly grade score that the PUR hot melt adhesive in the examples is relatively soft and skin-friendly;

[0117] Compared with Example 1, the PUR hot melt adhesive in Examples 4 and 5 uses a higher proportion of bio-based polyether polyol to significantly reduce the Shore hardness of the adhesive layer, while improving the peel strength retention rate after washing, because the high proportion of polyether enhances the flexibility and hydrolysis resistance of the adhesive layer, thereby improving the use comfort and durability of the PUR hot melt adhesive;

[0118] Compared with Example 1, the PUR hot melt adhesive in Comparative Examples 1 and 2 shows that the complex system in the reaction promoting control complex in the examples is the key to eliminating bubbles in the adhesive layer and ensuring flat bonding, and the absence of the system will cause the bubble rate to rise, affecting the appearance and performance of the fabric; during the chemical moisture curing process, the isocyanate group (-NCO) reacts with water to first generate unstable carbamic acid, which then quickly decomposes into amine and releases carbon dioxide (CO2), the amine reacts with diisocyanate to generate ureide, the urea group further reacts with the isocyanate group to finally generate insoluble and infusible impurities biuret; the reaction promoting control complex can react with or adsorb carbon dioxide, and the presence of the porous adsorbent material introduces a micropore structure, which has the triple functions of adsorbing carbon dioxide, carrying amine reaction promoters, amine catalysts and mosquito repellent microcapsules, and stabilizing the microcapsules, thereby synergistically promoting the rapid curing of the PUR hot melt adhesive, reducing the generation of bubbles during bonding, and improving the water washing resistance and mosquito repellent effect;

[0119] Compared with Example 1, the PUR hot melt adhesive in Comparative Example 3 shows that the mosquito repellent active ingredient of the mosquito repellent microcapsule in the example is effectively preserved, and through external force such as fabric friction, the wall material slowly breaks to release the essential oil core material, achieving long-term mosquito repellent effect;

[0120] Compared with Example 1, the PUR hot melt adhesive in Comparative Example 4 shows that the use of aliphatic diisocyanate instead of aromatic diisocyanate in the example can indeed reduce the softness of the adhesive.

[0121] The PUR hot melt adhesive prepared by the application has the advantages of high bio-based content, skin-friendly comfort, water washing resistance, flat bonding and long-term mosquito repellent effect, and is suitable for bonding processing of summer light and thin fabrics.

[0122] The foregoing description of the embodiments has been presented for the purpose of illustration and description. It is not intended to be exhaustive or to limit the application to the precise form disclosed. Modifications and variations are possible in light of the above teachings or can be acquired from practice of the application. As well, the description is presented in the context of the preferred embodiments as a number of alternatives. It is not intended to limit the application to the precise form described.

Claims

1. A bio-based PUR hot melt adhesive for summer fabric bonding, characterized in that, The raw materials of this hot melt adhesive include the following components in parts by weight: 40-60 parts of bio-based polyether polyol, 30-40 parts of bio-based polyester polyol, 20-25 parts of aliphatic diisocyanate, 0.5-1.5 parts of amine catalyst, 1-5 parts of mosquito repellent microcapsules, 1-5 parts of reaction-promoting and controlling compound, and 0.3-1 parts of antioxidant. The mosquito-repellent microcapsule comprises an essential oil core material and a wall material, wherein the mass ratio of the essential oil core material to the wall material is (0.5~1):1; The reaction-promoting control compound comprises an amine reaction promoter and a porous adsorbent material, wherein the mass ratio of the amine reaction promoter to the porous adsorbent material is (0.2~0.6):

1.

2. The bio-based PUR hot melt adhesive for summer fabric bonding according to claim 1, characterized in that, The essential oil core material is selected from one or more of eucalyptus oil, peppermint oil, sage oil, cedar oil, catnip oil, lemongrass oil, camphor oil, and lavender oil, and the wall material is melamine-modified urea-formaldehyde resin. The amine reaction promoter is selected from triethylamine, methyldiethanolamine, etc. N One or more of methylmorpholine and choline, wherein the porous adsorbent material is selected from one or more of diatomaceous earth, silica, and activated carbon.

3. The bio-based PUR hot melt adhesive for summer fabric bonding according to claim 2, characterized in that, The raw materials of the mosquito repellent microcapsule include an essential oil core emulsion and a wall material solution. The raw materials of the essential oil core emulsion include essential oil core material, surfactant, polyvinyl alcohol and water. The mass ratio of the essential oil core material, surfactant, polyvinyl alcohol and water is (0.5~1):(0.01~0.1):(0.01~0.05):(5~10). The raw materials of the wall material solution include wall material and water. The volume ratio of water in the wall material solution is 50~75%. The raw materials of the melamine-modified urea-formaldehyde resin include formaldehyde, urea and melamine. The molar ratio of formaldehyde, urea and melamine is (5~10):(1~5):(0.5~1.5). The average particle size of the mosquito-repellent microcapsules is 2~5 μm.

4. The bio-based PUR hot melt adhesive for summer fabric bonding according to claim 3, characterized in that, The preparation method of the mosquito-repellent microcapsules includes the following steps: S3.1 Mix essential oil core material, surfactant, polyvinyl alcohol and water, homogenize to obtain core material emulsion; S3.2 Mix formaldehyde, urea and melamine, adjust the pH, raise the temperature to form melamine-modified urea-formaldehyde resin prepolymer, dilute with water to obtain wall material solution; S3.3 Add wall material solution dropwise to core material emulsion. After the addition is complete, adjust the pH and allow the reaction to proceed. S3.4 After the reaction is complete, adjust the pH, filter, and obtain mosquito repellent microcapsules; In step S3.1, the homogenization speed is 3000~4000 rpm and the time is 1~10 min; In step S3.2, triethanolamine is used to adjust the pH to 8.0-8.5, the temperature is raised to 70-75 ℃, and the holding time is 1-3 h; In step S3.3, the dropping rate is 0.5~1.5 mL / min. After the dropping is completed, the pH is adjusted to 4.0~4.5 with formic acid solution. The reaction temperature is 65~75 ℃, the stirring speed is 1500~2500 rpm, and the time is 2~4 h. After the reaction in step S3.4 is completed, use ammonia water to adjust the pH to 7.0~7.

5.

5. The bio-based PUR hot melt adhesive for summer fabric bonding according to claim 1, characterized in that, The bio-based polyether polyol is castor oil-based polyether polyol. The raw materials of the castor oil-based polyether polyol include castor oil, formic acid, hydrogen peroxide, DMC catalyst, a mixture of monomers of propylene oxide and cyclohexane oxide, antioxidant and carbodiimide. The mass ratio of castor oil, formic acid, hydrogen peroxide, DMC catalyst, propylene oxide, cyclohexane oxide, antioxidant and carbodiimide is (50~150):(1~10):(10~30):(0.5~1.5):(50~250):(50~250):(0.1~1):(0.1~1). The castor oil-based polyether polyol has a number average molecular weight of 1000-2500 and a hydroxyl value of 75-150 mg KOH / g.

6. The bio-based PUR hot melt adhesive for summer fabric bonding according to claim 5, characterized in that, The method for preparing the castor oil-based polyether polyol includes the following steps: S2.1 Mix castor oil and formic acid, add hydrogen peroxide, filter, and obtain epoxidized castor oil; S2.2, Add DMC catalyst, dehydrate under vacuum, add a mixture of propylene oxide and cyclohexane oxide monomers, and react; S2.3 Add antioxidant and carbodiimide, mix, filter, and obtain castor oil-based polyether polyol; In step S2.2, the vacuum dehydration temperature is 100~120 ℃, the vacuum degree is ≤-0.09 MPa, and the time is 20~40 min. The reaction temperature was 110~120 ℃, and the time was 3~5 h; The mixing time in step S2.3 is 1 to 3 hours.

7. The bio-based PUR hot melt adhesive for summer fabric bonding according to claim 1, characterized in that, The bio-based polyester polyol is selected from one or more of castor oil polyester polyol, bio-based polyethylene adipate diol, and bio-based polycarbonate diol. The aliphatic diisocyanate is selected from one or more of isophorone diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate; The amine catalyst is selected from one or more of bismorpholino diethyl ether, triethylenediamine, and dimethylethanolamine; The antioxidant is selected from one or more of the following: 2,6-di-tert-butyl-4-methylphenol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], Eucommia ulmoides leaf extract, tannic acid, tea polyphenols, grape seed extract, curcumin, and glycyrrhizin.

8. A method for preparing a bio-based PUR hot melt adhesive for summer fabric bonding as described in any one of claims 1 to 7, characterized in that, The method includes the following steps: S1.1 Vacuum dehydration of bio-based polyether polyol, bio-based polyester polyol and antioxidant; S1.

2. Add aliphatic diisocyanate under a protective gas atmosphere, mix to form polyurethane prepolymer, add amine catalyst, and react. S1.3 Add reaction-promoting control compound and mosquito-repellent microcapsules, mix, and obtain a bio-based PUR hot melt adhesive for summer fabric bonding.

9. The method for preparing a bio-based PUR hot melt adhesive for summer fabric bonding according to claim 8, characterized in that, In step S1.1, the vacuum dehydration temperature is 100~120 ℃, the vacuum degree is ≤-0.09 MPa, and the time is 1~3 h; In step S1.2, the temperature at which the aliphatic diisocyanate is added under a protective gas atmosphere is 75~85 °C. The mixing temperature is 80~90 ℃, and the time is 2~3 h. The reaction temperature is 80~90 ℃, and the time is 30~60 min; In step S1.3, the temperature at which the reaction-promoting control compound and mosquito-repellent microcapsules are added is 65-70 °C. The mixing time is 1 to 2 hours.

10. The application of a bio-based PUR hot melt adhesive for summer fabric bonding as described in any one of claims 1 to 7 in summer clothing fabrics.

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