CN115926715A - Reactive moisture-curing polyurethane hot melt adhesive, preparation method and application thereof - Google Patents

Abstract

The invention belongs to the field of polymer chemistry, and particularly relates to a reactive moisture-curing polyurethane hot melt adhesive with high moisture permeability. The hot melt adhesive is prepared by reacting the following isocyanate component and isocyanate reactive component in parts by mass: the isocyanate component is: 20 to 35 parts by mass of isocyanate; the isocyanate-reactive component comprises: 35 to 45 parts by mass of at least one polyether polyol; 10 to 25 parts by mass of at least one polyester polyol; 5 to 10 parts by mass of at least one secondary amino polyether; and 3-8 parts by mass of a chain extender. The reactive moisture-curing polyurethane hot melt adhesive disclosed by the invention has excellent moisture permeability, high bonding strength and excellent washing resistance.

Description

Reactive moisture-curing polyurethane hot melt adhesive, preparation method and application thereof

Technical Field

The invention belongs to the field of polymer chemistry, and particularly relates to a reactive moisture-curable polyurethane hot melt adhesive with high moisture permeability.

Background

With the increasing living standard of human beings, the functional requirements of people on clothes are higher and higher, such as warm keeping, fashion, antibiosis, water resistance, moisture permeability, wind resistance and the like. The fabric with the waterproof and moisture permeable functions can reduce the stuffy feeling generated during sports, and is widely applied to the fields of sportswear, mountaineering wear, medical clothing, waterproof cloth, jacket, ski wear and the like.

A reactive moisture-curing polyurethane hot melt adhesive (PUR) is taken as one of environment-friendly adhesives and is widely applied to various fabric composite fabrics at present. If a general PUR product is adopted, the air and moisture permeability of the composite fabric can be greatly reduced, so researchers are dedicated to developing PUR products with high moisture permeability.

Chinese patent document CN108290993 discloses a preparation method of moisture-curing polyurethane hot melt adhesive: polyoxyethylene ether, aromatic polyester and crystalline polyester are used as the polyol component. The preparation method has the defect that the introduced polyoxyethylene ether and aromatic polyester polyol are not favorable for the washing resistance of the textile fabric.

Chinese patent document CN102167794 discloses a preparation method of polyurethane prepolymer: the polyalcohol is 75% or more of polytetramethylene glycol-ethylene glycol or polypropylene glycol, and the prepolymer prepared by the method has excellent moisture permeability and washing resistance, but the polyether content is high, so that the final bonding performance of the product is not facilitated.

Chinese patent document CN1341133 discloses a high moisture permeability polyurethane hot melt adhesive with good hydrolysis resistance, wherein two types of polyether polyol are adopted as raw materials, one type is polyoxyethylene oxypropylene copolyester diol with low oxyethylene content (lower than 40%), the other type is polyalkylene glycol with low molecular weight, and the polyester adopts crystalline polyester polyol. The hot melt adhesive prepared by the method has good water washing resistance, but has poor moisture permeability due to low content of ethylene oxide.

Chinese patent document CN101547991 discloses a moisture-curable polyurethane hot-melt adhesive, and a laminate and a moisture-permeable film using the same. The raw material adopts polyoxyethylene ether with high molecular weight, and the number average molecular weight is 2000-25000. The hot melt adhesive prepared by the method has good moisture permeability, but the polyether has high molecular weight and obvious crystallization, influences the compatibility with other polyol components, and has general adhesive property.

Chinese patent CN109401282 discloses a high-softness TPU film for clothes and a preparation method thereof. The compound containing acidic groups and micromolecular aliphatic diamine are simultaneously used as chain extenders, and primary amine and isocyanate form urea bonds and form a cross-linking structure, so that the soft hand feeling is difficult to realize.

Therefore, the preparation of a reactive moisture-curing polyurethane hot melt adhesive with excellent moisture permeability, bonding strength, water washing resistance and soft hand feeling is urgently needed.

Disclosure of Invention

The invention provides a reactive moisture-curing polyurethane hot melt adhesive PUR which is prepared by reacting an isocyanate component and an isocyanate reactive component in parts by mass as follows:

the isocyanate component is:

20 to 35 parts by mass of isocyanate, preferably 20 to 30 parts by mass, such as 20 parts by mass, 25 parts by mass or 30 parts by mass;

the isocyanate-reactive component comprises:

35 to 45 parts by mass, preferably 40 to 45 parts by mass, such as 35 parts by mass, 40 parts by mass or 45 parts by mass, of the at least one polyether polyol;

10 to 25 parts by mass, preferably 15 to 25 parts by mass, such as 14 parts by mass, 17 parts by mass, 22 parts by mass or 25 parts by mass, of at least one polyester polyol;

5 to 10 parts by mass, such as 5 parts by mass, 8 parts by mass, or 10 parts by mass, of at least one secondary amine-based polyether;

the chain extender is 3 to 8 parts by mass, such as 3 parts by mass, 5 parts by mass, or 8 parts by mass.

In a preferred embodiment, the isocyanate-reactive component does not comprise a polyoxyethylene ether. The polyoxyethylene ether has a poor water washing resistance and a strong moisture absorption property, so that it is not good for the use stability of the PUR product in an open state.

In a preferred embodiment, the polyester polyol in the isocyanate-reactive component is a crystalline polyester polyol.

Preferably, in the reactive moisture-curable polyurethane hot melt adhesive PUR described above, the chain extender is selected from small molecule diols containing carboxyl groups. Preferably, the carboxyl-containing small molecule dihydric alcohol is dimethylolpropionic acid and dimethylolbutyric acid. More preferably, the small molecule dihydric alcohol containing carboxyl is dimethylolpropionic acid.

Preferably, in the above reactive moisture-curing polyurethane hot melt adhesive PUR, the secondary amino polyether is a secondary amino polyoxypropylene ether, specifically selected from SD231, SD401 and SD2001 of hensman, with SD2001 being particularly preferred.

Preferably, in the above reactive moisture-curable polyurethane hot melt adhesive PUR, the polyether polyol is selected from one or more of polyoxyethylene polyol, polyoxypropylene polyol, polyoxyethylene-oxypropylene copolymer and polytetrahydrofuran polyol; preferably, the polyether polyol is a polyoxyethylene-oxypropylene copolymer; more preferably, the polyether polyol has an oxyethylene group content of 70 to 95% by weight and a hydroxyl value of 25 to 120mgKOH/g. The polyether polyol selected by the invention has stronger hydrophilicity due to higher content of ethylene oxide, can obviously improve the moisture permeability of PUR, and simultaneously contains partial propylene oxide to break the crystallinity of the polyethylene oxide, so that the production is convenient and the water washing resistance is improved.

Preferably, in the reactive moisture-curable polyurethane hot melt adhesive PUR, the polyester polyol is a crystalline polyester polyol. Wherein the molecular main chain of the crystalline polyester polyol does not contain a side methyl group, and the hydroxyl value is 20-300 mgKOH/g, preferably 30-120 mgKOH/g;

preferably, the crystalline polyester polyol may be obtained by reacting a dibasic acid selected from one or more of ethylene glycol, butanediol, hexanediol, octanediol, and decanediol, and a dibasic alcohol selected from one or more of adipic acid, octanedioic acid, sebacic acid, and dodecanedioic acid. Can also be obtained by opening lactone ring, such as caprolactone, valerolactone and the like, and preferably, the initiator of the polycaprolactone is dimethylolpropionic acid.

The isocyanate component refers to a compound having an isocyanate group, and examples thereof include, but are not limited to, tolylene Diisocyanate (TDI), diphenylmethane diisocyanate (MDI), 1, 5-Naphthalene Diisocyanate (NDI), hexamethylene Diisocyanate (HDI), methylcyclohexyl diisocyanate, 4' -dicyclohexylmethane diisocyanate, isophorone diisocyanate (IPDI), p-phenylene diisocyanate (PPDI), p-phenylene diisocyanate (XDI), tetramethyldimethylene diisocyanate (TMXDI), 1, 4-cyclohexane diisocyanate (CHDI), cyclohexane dimethylene diisocyanate (HXDI), trimethyl-1, 6-hexamethylene diisocyanate (TMHDI), norbornane diisocyanate (NBDI), dimethylbiphenyl diisocyanate (TODI), methylcyclohexyl diisocyanate (HTDI), and the like, and polymers, modified products, and the like of such compounds, which may be used alone or in combination (above); preferably, the isocyanate component is preferably diphenylmethane diisocyanate.

Preferably, in the reactive moisture-curable polyurethane hot melt adhesive PUR, the molar ratio of the isocyanate groups in the isocyanate component to the active hydrogen in the isocyanate-reactive component is 1.1 to 3.0:1, preferably 1.5 to 1.8:1, such as 1.5:1,1.6:1 or 1.8:1; the active hydrogen is derived from: hydroxyl groups of the polyether polyol; hydroxyl groups of polyester polyols; amine groups of secondary amine based polyethers; the chain extender is the hydroxyl group of dimethylolpropionic acid.

The reactive moisture-curing polyurethane hot melt adhesive PUR according to the invention may optionally be supplemented with one or more auxiliaries known from the prior art.

Such adjuvants include, but are not limited to, catalysts, stabilizers, chain extenders, fillers, dyes, defoamers, thixotropic aids, plasticizers, coupling agents, adhesion promoters, leveling agents, and the like as are known in the art.

Preferably, in the reactive moisture-curable polyurethane hot melt adhesive PUR, the reactive moisture-curable polyurethane hot melt adhesive further includes at least one of the following additives in parts by mass:

catalysts refer to a class of compounds commonly used in the art for catalyzing the reaction of isocyanate groups with active hydrogen atoms, examples of which include, but are not limited to, stannous octoate, dibutyltin dilaurate, 2-dimorpholinodiethyl ether, triethylenediamine, triethanolamine, and the like.

The stabilizer is one or a combination of an antioxidant and a light stabilizer. The antioxidant is one or more of BHT, CHINOX 1010, CHINOX 1076, CHINOX 1098, CHINOX1024, CHINOX 245, CHINOX 1035 and CHINOX 1135; the light stabilizer is one or more of CHISORB 320, UV-1, UV-P, UV-292 and UV-329.

Coupling agents are well known in the art and include, but are not limited to, aminopropyltriethoxysilane, glycidoxypropyltrimethoxysilane, methacryloxypropyltrimethoxysilane, and the like.

The antifoaming agent refers to a polymer of polyolefin, polysiloxane, etc. commonly used in the art for improving the use properties of products.

In a specific embodiment, the method for preparing the reactive moisture-curable polyurethane hot melt adhesive PUR comprises the following steps:

(1) Taking raw materials of polyether polyol and polyester polyol into a four-neck flask, and then vacuumizing and dehydrating to ensure that the moisture content is not more than 0.03wt%; (2) Adding metered isocyanate into a four-neck flask, controlling the temperature in the flask to be 60-80 ℃, and reacting for 2-4 h; (3) Then adding a metered antioxidant and a metered catalyst under a stirring state; (4) Continuously adding metered secondary amine polyhydric alcohol, controlling the reaction temperature to be 60-80 ℃, and stirring for reaction for 0.5-2h; (5) Increasing the reaction temperature to 110-120 ℃, then adding metered dimethylolpropionic acid, controlling the reaction temperature to 110-120 ℃, and stirring for reaction for 1-3 h; (6) Then adding a metered coupling agent, controlling the reaction temperature to be 110-120 ℃, and stirring for reaction for 0.5-2h; (7) When the NCO value in the reaction system reaches the theoretical NCO value of +/-0.2 wt%, uniformly stirring, discharging, and hermetically packaging to obtain the PUR product.

The temperature of vacuum dehydration in the step (1) is 100-120 ℃, and the time is 1-4h.

The invention also provides application of the reactive moisture-curing polyurethane hot melt adhesive PUR in the adhesion of textile fabrics, wherein the textile fabrics comprise but are not limited to polyester fabrics, nylon fabrics, blended fabrics, TPU films, PU films and PTFE films, and the fabrics can be of non-waterproof grade or high-waterproof grade.

It should be noted that all the technical effects described in the present invention are the comprehensive effects of all the components and the mutual cooperation.

The technical scheme of the invention has the following advantages:

(1) The invention uses dimethylolpropionic acid as chain extender, and the introduction of carboxyl can improve the moisture permeability of the product on one hand, and can inhibit side effects in carbamate reaction on the other hand, thereby improving the production and the service performance of the product. The water-washing resistance of the fabric composite product is reduced to a certain extent due to the water solubility of dimethylolpropionic acid, and the polyurethane hot melt adhesive product with excellent water-washing resistance can be prepared by sharing dimethylolpropionic acid and secondary amine polyether and enhancing the bond energy between molecules and a fabric substrate.

(2) The raw materials are mutually cooperated, and the prepared reactive moisture-curing polyurethane hot melt adhesive has excellent moisture permeability and peel strength and excellent water washing resistance.

Detailed Description

The invention is further described with reference to the following examples, but is not intended to be limited thereto.

The examples and comparative examples are as follows:

isocyanate: wannate MDI-100, diphenylmethane diisocyanate, van der Chemie group Ltd;

polyether polyol 2A: a polyoxyethylene-oxypropylene copolymer, a glycol, wherein the oxyethylene content is 75% by weight, and the hydroxyl value is 30mgKOH/g;

polyether polyol 2B: a polyoxyethylene glycol having an oxyethylene content of 100% by weight and a hydroxyl value of 56mgKOH/g;

crystalline polyester 3A: obtained by the reaction of dodecanedioic acid and hexanediol, and the hydroxyl value is 32mgKOH/g;

crystalline polyester 3B: obtained by the reaction of adipic acid and hexanediol, and the hydroxyl value is 112 mgKOH/g;

crystalline polyester 3C: obtained by the reaction of adipic acid and hexanediol, and the hydroxyl value is 14mgKOH/g;

crystalline polyester 3D: obtained by the reaction of adipic acid and hexanediol, and the hydroxyl value is 32mgKOH/g;

dimethylolpropionic acid, chemically pure, GEO specialty chemicals;

SD2001 Secondary Amino polyether, supplier Huntman;

antioxidant 1010: pentaerythrityl tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], double bond chemical industry;

catalyst: DMDEE, 2-dimorpholinodiethyl ether;

coupling agent: KH560, gamma-glycidoxypropyltrimethoxysilane.

The raw material ratios of examples 1 to 4 and comparative examples 1 to 2 are shown in Table 1.

TABLE 1 raw material ratios of examples and comparative examples

Raw materials in parts by mass	Example 1	Example 2	Example 3	Example 4	Comparative example 1	Comparative example 2
							Isocyanates	20	25	31	35	21	21
Polyether polyol 2A	42	40	0	0	42	42
							Polyether polyol 2B	0	0	45	35	0	0
Crystalline polyester 3A	5	4	0	0	0	0
							Crystalline polyester 3B	0	0	0	0	37	0
Crystalline polyester 3C	20	0	0	0	0	32
							Crystalline polyester 3D	0	18	14	17	0	0
SD2001	10	8	5	5	0	0
							Dimethylolpropionic acid	3	5	6	8	0	5
Antioxidant 1010	0.01	0.01	0.01	0.01	0.01	0.01
							Catalyst DMDEE	0.05	0.05	0.05	0.05	0.05	0.05
Coupling agent KH560	0.5	0.5	0.5	0.5	0.5	0.5
							NCO，％	3	3.4	3.9	4.7	2.9	2.5
R	1.8	1.7	1.6	1.7	1.7	1.6

The preparation process of the reactive moisture-curing polyurethane hot melt adhesive PURs of examples 1 to 4 and comparative examples 1 to 2 comprises the following steps: (1) According to the mixture ratio of the raw materials in the table 1, taking and adding metered polyether polyols 2A-2B and polyester polyols 3A-3D into a four-neck flask, and then dehydrating in vacuum at 120 ℃ for 2 hours to ensure that the moisture content is not more than 0.03wt%; (2) Then adding metered isocyanate into a four-neck flask, controlling the temperature in the flask to be 80 ℃, and reacting for 3 hours; (3) Then adding a metered antioxidant and a metered catalyst under a stirring state; (4) Continuously adding metered secondary amine-based polyol, controlling the reaction temperature to be 80 ℃, and stirring for reaction for 1h; (5) Increasing the reaction temperature to 120 ℃, then adding metered dimethylolpropionic acid, controlling the reaction temperature to 120 ℃, and stirring for reaction for 1h; (5) Then adding a metered coupling agent KH560, controlling the reaction temperature at 120 ℃, and stirring for reaction for 0.5h; (6) And when the NCO value in the reaction system reaches the theoretical NCO value of +/-0.2 wt%, uniformly stirring, discharging, and hermetically packaging to obtain the corresponding PUR product.

The reactive moisture-curing polyurethane hot melt adhesive PUR samples prepared by using the raw material ratios of the examples 1 to 4 and the comparative examples 1 to 2 were respectively used for laminating a fabric and a TPU film, wherein the fabric is 75D Chunzhan, the TPU film is a middle permeable film, after the compounding, the polyurethane hot melt adhesive PUR samples were cured for 24 hours at a temperature of 23 ℃ and a humidity of 50%, and then the performances were tested according to the following methods.

Peel force test method: adhering the hot-melt adhesive tape to the cured cloth film product by using an electric iron, cutting the hot-melt adhesive tape into pieces with the standard length of 2.5cm, and testing the stripping force by using a tensile machine.

Moisture permeability test method: according to the ASTM E96BW standard, the inverted cup method is adopted, a cut cloth film sample prepared in the way of compounding with a certain area is respectively fixed in a sample cup filled with purified water, then the sample cup is inverted on a rotating disc in a moisture permeable instrument, the mass difference within a certain time difference is recorded, and the moisture permeability (g/m) of the sample is calculated through the secondary mass difference ² ﹒24h)。

Water washing resistance test method: respectively washing the prepared composite cloth film sample in a washing machine for 1h at 40 ℃; the total number of washes was 20.

Specific test results are shown in table 2.

TABLE 2 test results of examples 1 to 4 and comparative examples 1 to 2

Performance test	Example 1	Example 2	Example 3	Example 4	Comparative example 1	Comparative example 2
							Viscosity, cps (90 ℃ C.)	3200	3600	4200	3300	3000	7000
Peel force, N/2.5cm	15	16	18	18	8	6
							Moisture permeability (g/m 2.24h)	5700	5800	6000	5500	5000	5400
Washing with water for 20 times	Without delaminating	Without delaminating	Without delaminating	Without delaminating	Without delaminating	Delamination of

As is clear from Table 2, the PURs prepared in examples 1 to 4, when used for fabric compounding, had higher peel strength, good moisture permeability and excellent water-washing resistance, as compared with those of comparative examples 1 to 2. Comparative example 1 no dimethylolpropionic acid and secondary amine-based polyether were added, and both moisture permeability and peel force were inferior to those of example 1. Comparative example 2 no secondary amine based polyether was added and the peel force and water wash resistance were inferior to example 1.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.

Claims (10)

1. A reactive moisture-curing polyurethane hot melt adhesive is prepared by reacting the following isocyanate component and isocyanate reactive component in parts by mass:

the isocyanate component is:

20 to 35 parts by mass of isocyanate, preferably 20 to 30 parts by mass;

the isocyanate-reactive component comprises:

35 to 45 parts by mass, preferably 40 to 45 parts by mass, of at least one polyether polyol;

10 to 25 parts by mass, preferably 15 to 25 parts by mass, of at least one polyester polyol;

5-10 parts of at least one secondary amine polyether;

3-8 parts of a chain extender.

2. The reactive moisture-curing polyurethane hot melt adhesive of claim 1, wherein the chain extender in the isocyanate-reactive component is dimethylolpropionic acid.

3. The reactive moisture-curing polyurethane hot melt adhesive of claim 1 or 2, wherein the secondary amine polyether in the isocyanate-reactive component is a secondary amine polyoxypropylene ether.

4. The reactive moisture-curable polyurethane hot melt adhesive according to any one of claims 1 to 3, wherein the polyether polyol is selected from one or more of a polyoxyethylene polyol, a polyoxypropylene polyol, a polyoxyethylene-oxypropylene copolymer and a polytetrahydrofuran polyol; preferably, the polyether polyol is a polyoxyethylene-oxypropylene copolymer; and/or the polyester polyol is a crystalline polyester polyol, and preferably the molecular main chain of the crystalline polyester polyol does not contain a side methyl group, and the hydroxyl value is 20 to 300mgKOH/g, preferably 30 to 120mgKOH/g.

5. The reactive moisture-curable polyurethane hot melt adhesive according to any one of claims 1 to 4, wherein the isocyanate component is selected from compounds having isocyanate groups such as Toluene Diisocyanate (TDI), diphenylmethane diisocyanate (MDI), 1, 5-Naphthalene Diisocyanate (NDI), hexamethylene Diisocyanate (HDI), methylcyclohexyl diisocyanate, 4' -dicyclohexylmethane diisocyanate, isophorone diisocyanate (IPDI), p-phenylene diisocyanate (PPDI), p-phenylene diisocyanate (XDI), tetramethyldimethylene diisocyanate (TMXDI), 1, 4-cyclohexane diisocyanate (CHDI), cyclohexanedimethylene diisocyanate (HXDI), trimethyl-1, 6-hexamethylene diisocyanate (TMHDI), norbornane diisocyanate (NBDI), dimethylbiphenyl diisocyanate (TODI), methylcyclohexyl diisocyanate (HTDI) and the like, and polymer polymers and modified products of such compounds.

6. The reactive moisture-curing polyurethane hot melt adhesive according to any one of claims 1 to 5, wherein the molar ratio of the isocyanate groups in the isocyanate component to the active hydrogens in the isocyanate-reactive component is from 1.1 to 3.0:1, preferably 1.5 to 1.8:1.

7. the reactive moisture-curing polyurethane hot melt adhesive according to any one of claims 1 to 6, wherein the reactive moisture-curing polyurethane hot melt adhesive PUR further comprises one or more auxiliary agents, wherein the auxiliary agents include, but are not limited to, catalysts, stabilizers, chain extenders, fillers, dyes, defoamers, thixotropic auxiliaries, plasticizers, coupling agents, adhesion promoters, and leveling agents.

8. The reactive moisture-curing polyurethane hot melt adhesive of claim 7, further comprising at least one of the following additives in parts by mass:

9. the reactive moisture-curing polyurethane hot melt adhesive of claim 7 or 8, wherein the catalyst is selected from stannous octoate, dibutyltin dilaurate, 2-dimorpholinodiethyl ether, triethylenediamine, triethanolamine; and/or the stabilizer is one or a combination of an antioxidant and a light stabilizer, wherein the antioxidant is one or more of BHT, CHINOX 1010, CHINOX 1076, CHINOX 1098, CHINOX1024, CHINOX 245, CHINOX 1035 and CHINOX 1135; the light stabilizer is one or more of CHISORB 320, UV-1, UV-P, UV-292 and UV-329; and/or the coupling agent is selected from aminopropyltriethoxysilane, glycidoxypropyltrimethoxysilane and methacryloxypropyltrimethoxysilane; and/or the defoaming agent is selected from polymers of polyolefin and polysiloxane.

10. Use of the reactive moisture-curing polyurethane hot melt adhesive according to any one of claims 1 to 9 for bonding textile fabrics including, but not limited to, polyester fabrics, nylon fabrics, blended fabrics, TPU films, PU films, PTFE films.