High-resilience and hydrolysis-resistant thermoplastic polyurethane adhesive as well as preparation method and application thereof

Abstract

The invention discloses a thermoplastic polyurethane adhesive with high resilience and hydrolysis resistance as well as a preparation method and application of the thermoplastic polyurethane adhesive, and the thermoplastic polyurethane adhesive is prepared by reacting 60-95 wt% of a special polyester polyol component with 0-25 wt% of a chain extender and 5-30 wt% of diisocyanate and adopting screw extrusion. The thermoplastic polyurethane adhesive disclosed by the invention has excellent properties of low activation temperature, high resilience and hydrolysis resistance, and has a very good market prospect.

Description

Technical Field

[0001] The invention belongs to the field of polymer material manufacturing, and in particular relates to a high-resilience and hydrolysis-resistant thermoplastic polyurethane adhesive and a preparation method and application thereof. Background Art

[0002] Polyurethane adhesive refers to an adhesive containing carbamate groups or isocyanate groups in the molecular chain. Because the molecular chain contains isocyanate groups and carbamate groups, polyurethane adhesives show high activity and polarity. High-resilience thermoplastic polyurethane elastomers are mainly used for bonding sports bras and yoga clothes, with high added value. Conventional thermoplastic polyurethane elastomers have poor elastic recovery and cannot be used in this field. In addition, yoga clothes and sports bras are often in high-humidity environments, which also puts forward high requirements on the hydrolysis resistance of the material. At present, many patents have explored how to obtain high-resilience thermoplastic polyurethane elastomers.

[0003] Chinese patent CN100344666C discloses a new chain extender 2,4-diamino-6-R-1,3,5-triazine for synthesizing polyurethane elastomers. A thermoplastic polyurethane elastomer with good elastic recovery is synthesized by using the chain extender, polyol and isocyanate. However, the introduction of this chain extender also increases the use temperature of the thermoplastic polyurethane elastomer, limiting the use of some fabrics.

[0004] Chinese patent CN 110903805 A discloses a thermoplastic polyurethane elastomer synthesized from modified terminal hydroxyl hydrogenated polybutadiene polyol, aliphatic or aromatic diisocyanate and a small molecule chain extender, which is then mixed with SEBS / SEPS rubber powder to obtain a high-resilience and hydrolysis-resistant polyurethane hot melt adhesive. The hot melt adhesive has the advantages of low polarity, high resilience, low thermal activation temperature, low pressure change, low density, low dielectric constant, etc. It has a good effect on bonding low-polarity or non-polar materials and has good resilience, but the product has a poor bonding effect on some polar fabrics.

[0005] So far, there are few reports of thermoplastic polyurethanes with both high resilience and hydrolysis resistance at home and abroad. Therefore, based on market demand, it is very promising to develop thermoplastic polyurethane elastomers with better resilience and hydrolysis resistance. Summary of the invention

[0006] The object of the present invention is to provide a hydrolysis-resistant, high-rebound thermoplastic polyurethane adhesive with excellent properties of low activation temperature, high rebound and hydrolysis resistance in view of the shortcomings of the prior art.

[0007] Another object of the present invention is to provide a preparation method and application of the thermoplastic polyurethane adhesive.

[0008] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0009] A high-resilience and hydrolysis-resistant thermoplastic polyurethane adhesive, comprising the following components polymerized:

[0010] a) 60-95wt% of special polyester polyol, for example, 60wt%, 65wt%, 70wt%, 75wt%, 80wt%, 85wt%, 90wt%, etc., preferably 70-90wt%;

[0011] b) chain extender 0-25wt%, such as 1wt%, 5wt%, 10wt%, 15wt%, 20wt%, etc., preferably 3-20wt%;

[0012] c) 5-30 wt% of diisocyanate, for example 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, etc., preferably 10-25 wt%.

[0013] In some specific embodiments, the isocyanate index R value (NCO:OH molar ratio in the reaction system) is 0.85 to 1.1, such as 0.9, 0.95, 1.05, etc., preferably 0.90 to 1.08.

[0014] In some specific embodiments, the special polyester polyol is a homopolymer polyester polyol or a divalent copolyester polyol obtained by initiating a cyclic ester monomer with an initiator;

[0015] In some specific embodiments, the initiator is selected from C6-C 28 The substituted diol is preferably C8-C 22 A diol containing a cyclic substituent or a diol containing a long-chain substituent, more preferably one or more of cyclopentane-1,3-diol, 1,2-cyclohexanediol, 1,2-nonanediol, 1,5-cyclooctanediol, and 1,4-cyclohexanedimethanol;

[0016] The cyclic ester monomer is selected from C 4-10 lactone, C 4-10 Lactide, C 12-23 One or more of the cyclic lactones and their alkyl substituents, preferably one or more of β-butyrolactone, ε-caprolactone, γ-valerolactone, rac-lactide, glycolide, cyclopentadecenolactone, cyclododecalactone, 15-pentadecanolactone, and 16-hexadecanoic acid lactone, preferably two or more.

[0017] In some specific embodiments, the molar ratio of the initiator to the total amount of the cyclic ester monomers is 1:10 to 1:30, for example, 1:12, 1:16, 1:20, 1:24, 1:28, etc., preferably 1:12 to 1:25.

[0018] In some specific embodiments, the number average molecular weight of the special polyester polyol is 1000-6000 g / mol, for example, 1500 g / mol, 2000 g / mol, 2500 g / mol, 3000 g / mol, 3500 g / mol, 4000 g / mol, 4500 g / mol, 5000 g / mol, 5500 g / mol, etc., preferably 2000-4000 g / mol.

[0019] In some specific embodiments, the molar ratio of the two cyclic ester monomers in the binary copolyester polyol is 1:5 to 5:1, such as 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, 4:1, etc., preferably 1:2 to 2:1;

[0020] In some specific embodiments, the chain extender is C 8-30 The aromatic polyol is preferably one or more of hydroquinone dihydroxyethyl ether, resorcinol dihydroxyethyl ether, resorcinol bishydroxypropyl ethyl ether, bishydroxyethyl bisphenol A, 2-[bis(4-hydroxyphenyl)methyl]benzyl alcohol, and 1,5-dihydroxy-1,2,3,4-tetralin, and more preferably one or more of hydroquinone dihydroxyethyl ether, resorcinol dihydroxyethyl ether, and bishydroxyethyl bisphenol A.

[0021] In some specific embodiments, the diisocyanate is one or more of diphenylmethane diisocyanate, hexamethylene diisocyanate, 4,4-dicyclohexylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, meta-xylylene diisocyanate, and 1,5-naphthalene diisocyanate, preferably one or more of hexamethylene diisocyanate, diphenylmethane diisocyanate, and isophorone diisocyanate.

[0022] In some specific embodiments, the special polyester polyol is prepared by a method comprising the following steps: adding all monomers and initiators according to the formula ratio, reacting at a temperature of 130 to 180°C, for example, 140°C, 150°C, 160°C, 170°C, etc., preferably 140 to 170°C, reacting under an inert atmosphere, and reacting for 4 to 14 hours, for example, 5 hours, 8 hours, 10 hours, 12 hours, 13 hours, etc., preferably 5 to 10 hours, to obtain the special polyester polyol.

[0023] On the other hand, the method for preparing the aforementioned high resilience and hydrolysis resistant thermoplastic polyurethane adhesive comprises the steps of uniformly mixing a polyol component with a diisocyanate component and an optional chain extender component, and then extruding the mixture through a twin-screw reaction;

[0024] Preferably, the extrusion temperature is 130-200°C, for example, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, etc., more preferably 140-180°C.

[0025] On the other hand, the aforementioned high resilience and hydrolysis-resistant thermoplastic polyurethane adhesive or the high resilience and hydrolysis-resistant thermoplastic polyurethane adhesive prepared by the aforementioned preparation method is used in the bonding of PVC, fabric, leather or foam materials, especially in the bonding of elastic fabrics.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The invention uses polyester initiated by a specific structure initiator as a polyol component to react with a chain extender and a diisocyanate to obtain a thermoplastic polyurethane adhesive with high resilience and hydrolysis resistance. Compared with the products in the prior art, the thermoplastic polyurethane adhesive has good hydrolysis resistance, high resilience, low-temperature activation and excellent comprehensive performance. DETAILED DESCRIPTION

[0028] The implementation method of the present invention is described in detail below, but the present invention is not limited thereto.

[0029] Preparation Example

[0030] Preparation of 16-hexadecanolide polyester polyol (HDL 3000):

[0031] 1,5-Cyclooctanediol and 16-hexadecanolide were added into a reactor in a molar ratio of 1:12, the temperature was raised to 150°C, and the reaction was carried out under nitrogen protection for 10 hours to obtain the target product, and the molecular weight thereof was determined to be 3000 g / mol by end hydroxyl titration analysis.

[0032] Preparation of 16-hexadecanolide-lactide copolyester polyol (HDL-LA2000):

[0033] 1,5-Cyclooctanediol, lactide and 16-hexadecanolide were added into a reactor in a molar ratio of 1:6:6, the temperature was raised to 150°C, and the target product was obtained by reacting for 8 hours under nitrogen protection. The molecular weight of the target product was determined to be 2000 g / mol by end hydroxyl titration analysis.

[0034] Preparation of caprolactone-lactide copolyester polyol (CL-LA3000):

[0035] 1,2-nonanediol, caprolactone and lactide were added into the reaction kettle in a molar ratio of 1:20:4, the temperature was raised to 140°C, and the reaction was carried out for 5 hours under nitrogen protection to obtain the target product. The molecular weight of the target product was determined to be 3000 g / mol by end hydroxyl titration analysis.

[0036] Preparation of 16-hexadecanolide-lactide copolyester polyol (HDL-LA3000):

[0037] Cyclopentane-1,3-diol, lactide and 16-hexadecanolide were added into a reactor in a molar ratio of 1:9:6, the temperature was raised to 160°C, and the reaction was carried out under nitrogen protection for 10 hours to obtain the target product, and the molecular weight thereof was determined to be 3000 g / mol by end hydroxyl titration analysis.

[0038] Preparation of 15-pentadecanolactone-16-hexadecanoic acid lactone copolyester polyol (PDL-HDL 3000):

[0039] 1,2-cyclohexanediol, 15-pentadecanolactone and 16-hexadecanoic acid lactone were added into the reaction kettle in a molar ratio of 1:6:6, the temperature was raised to 170°C, and the reaction was carried out under nitrogen protection for 9 hours to obtain the target product, and the molecular weight thereof was determined to be 3000 g / mol by end hydroxyl titration analysis.

[0040] Preparation of 15-pentadecanolactone-lactide copolyester polyol (PDL-LA 4000):

[0041] 1,4-cyclohexanedimethanol, lactide and 15-pentadecanolactone were added into a reaction kettle in a molar ratio of 1:6:18, the temperature was raised to 170°C, and the reaction was carried out under nitrogen protection for 13 hours to obtain the target product. The molecular weight of the product was determined to be 4000 g / mol by end hydroxyl titration analysis.

[0042] Example 1

[0043] 71wt% of HDL-LA 2000, 19wt% of isophorone diisocyanate and 10wt% of hydroquinone dihydroxyethyl ether were mixed evenly, and then subjected to twin-screw reaction extrusion (extruder temperature 150°C) to obtain a thermoplastic polyurethane adhesive with high resilience and hydrolysis resistance.

[0044] Example 2

[0045] 79wt% of CL-LA 3000, 14wt% of 4,4-diphenylmethane diisocyanate and 7wt% of resorcinol dihydroxyethyl ether were mixed evenly, and then subjected to twin-screw reaction extrusion (extruder temperature 160°C) to obtain a thermoplastic polyurethane adhesive with high resilience and hydrolysis resistance.

[0046] Example 3

[0047] 71wt% of HDL-LA3000, which accounts for 71wt% of the total raw material mass, is mixed evenly with 12wt% of hexamethylene diisocyanate and 17wt% of bishydroxyethyl bisphenol A, and then subjected to twin-screw reaction extrusion (extruder temperature 160°C) to obtain a thermoplastic polyurethane adhesive with high resilience and hydrolysis resistance.

[0048] Example 4

[0049] 77 wt% of HDL-LA 3000, 14 wt% of 4,4'-dicyclohexylmethane diisocyanate and 9 wt% of bishydroxyethyl bisphenol A were uniformly mixed, and then subjected to twin-screw reaction extrusion (extruder temperature 170°C) to obtain a thermoplastic polyurethane adhesive with high resilience and hydrolysis resistance.

[0050] Example 5

[0051] 79wt% of PDL-HDL 3000, which accounts for 79wt% of the total raw material mass, is mixed evenly with 12wt% of hexamethylene diisocyanate and 9wt% of hydroquinone dihydroxyethyl ether, and then subjected to twin-screw reaction extrusion (extruder temperature 170°C) to obtain a thermoplastic polyurethane adhesive with high resilience and hydrolysis resistance.

[0052] Example 6

[0053] 83wt% of PDL-HDL 3000, 12wt% of isophorone diisocyanate and 5wt% of hydroquinone dihydroxyethyl ether were mixed evenly, and then subjected to twin-screw reaction extrusion (extruder temperature 160°C) to obtain a thermoplastic polyurethane adhesive with high resilience and hydrolysis resistance.

[0054] Example 7

[0055] 84wt% of PDL-LA 4000, 11wt% of 4,4-diphenylmethane diisocyanate and 5wt% of hydroquinone dihydroxyethyl ether were mixed evenly, and then subjected to twin-screw reaction extrusion (extruder temperature 160°C) to obtain a thermoplastic polyurethane adhesive with high resilience and hydrolysis resistance.

[0056] Comparative Example 1

[0057] 81 wt% of HDL3000, 13 wt% of isophorone diisocyanate and 6 wt% of hydroquinone dihydroxyethyl ether were mixed evenly, and then subjected to twin-screw reaction extrusion (extruder temperature 150° C.) to obtain a thermoplastic polyurethane adhesive.

[0058] Comparative Example 2

[0059] 82 wt% of PCL3000, 13 wt% of 4,4-diphenylmethane diisocyanate and 5 wt% of hydroquinone dihydroxyethyl ether were mixed evenly, and then subjected to twin-screw reaction extrusion (extruder temperature 160° C.) to obtain a thermoplastic polyurethane adhesive.

[0060] Thermoplastic polyurethane elastomer performance tests are as follows:

[0061] Hardness is tested according to ASTM D2240 standard;

[0062] Tensile strength is tested according to GB / T 528-2009 standard;

[0063] The permanent deformation at fixed elongation (%) is tested according to HG / T3322 standard. The smaller the permanent deformation at fixed elongation, the better the resilience performance.

[0064] The peel strength test substrate is polyester canvas, and the lamination temperature is 140°C.

[0065] The hydrolysis resistance test conditions are in a constant temperature and humidity chamber (70°C / 95% humidity). After 14 days, the peel strength is compared with that of a blank sample.

[0066] The performance data of the TPU provided by the above examples and comparative examples are shown in Table 1.

[0067] Table 1

[0068]

[0069]

[0070] As can be seen from the above table, the high resilience and hydrolysis-resistant thermoplastic polyurethane adhesive prepared by the homopolymerized polyester polyol or divalent copolymerized polyester polyol obtained by initiating cyclic ester monomers in the present invention has good hydrolysis resistance, high resilience and low-temperature activation, and has excellent comprehensive performance compared to the products in the prior art.

Claims

1. A high resilience and hydrolysis resistant thermoplastic polyurethane adhesive, characterized in that: It includes the polymerization reaction of the following components: a) 60-95wt%, preferably 70-90wt% of special polyester polyol; b) chain extender 0-25wt%, preferably 3-20wt%; c) 5 to 30 wt % of diisocyanate, preferably 10 to 25 wt %.

2. The thermoplastic polyurethane adhesive according to claim 1, characterized in that The special polyester polyol is a homopolymer polyester polyol or a divalent copolymer polyester polyol obtained by initiating a cyclic ester monomer with an initiator; The initiator is selected from C6-C 28 The substituted diol is preferably C8-C 22 A diol containing a cyclic substituent or a diol containing a long-chain substituent, more preferably one or more of cyclopentane-1,3-diol, 1,2-cyclohexanediol, 1,2-nonanediol, 1,5-cyclooctanediol, and 1,4-cyclohexanedimethanol; The cyclic ester monomer is selected from C 4-10 lactone, C 4-10 Lactide, C 12-23 One or more of cyclic lactones and alkyl substituents thereof, preferably one or more of β-butyrolactone, ε-caprolactone, γ-valerolactone, rac-lactide, glycolide, cyclopentadecenolactone, cyclododecalactone, 15-pentadecanolactone, and 16-hexadecanoic acid lactone.

3. The thermoplastic polyurethane adhesive according to claim 2, characterized in that The molar ratio of the initiator to the total amount of the cyclic ester monomers is 1:10 to 1:30, preferably 1:12 to 1:

25.

4. The thermoplastic polyurethane adhesive according to any one of claims 1 to 3, characterized in that: The number average molecular weight of the special polyester polyol is 1000-6000 g / mol, preferably 2000-4000 g / mol.

5. The thermoplastic polyurethane adhesive according to any one of claims 1 to 4, characterized in that: The molar ratio of the two cyclic ester monomers in the binary copolyester polyol is 1:5 to 5:1, preferably 1:2 to 2:1; 6. The thermoplastic polyurethane adhesive according to any one of claims 1 to 5, characterized in that: The chain extender is C 8-30 The aromatic polyol is preferably one or more of hydroquinone dihydroxyethyl ether, resorcinol dihydroxyethyl ether, resorcinol bishydroxypropyl ethyl ether, bishydroxyethyl bisphenol A, 2-[bis(4-hydroxyphenyl)methyl]benzyl alcohol, and 1,5-dihydroxy-1,2,3,4-tetralin, and more preferably one or more of hydroquinone dihydroxyethyl ether, resorcinol dihydroxyethyl ether, and bishydroxyethyl bisphenol A.

7. The thermoplastic polyurethane adhesive according to any one of claims 1 to 6, characterized in that: The diisocyanate is one or more of diphenylmethane diisocyanate, hexamethylene diisocyanate, 4,4-dicyclohexylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, meta-xylylene diisocyanate, and 1,5-naphthalene diisocyanate, preferably one or more of hexamethylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, and 4,4-dicyclohexylmethane diisocyanate.

8. The thermoplastic polyurethane adhesive according to any one of claims 1 to 8, characterized in that: The special polyester polyol is prepared by a method comprising the following steps: adding all monomers and initiators according to the formula ratio, reacting at a reaction temperature of 130 to 180° C., preferably 140 to 170° C., reacting under an inert atmosphere, and reacting for 4 to 14 hours, preferably 5 to 10 hours, to obtain the special polyester polyol.

9. The method for preparing the high-resilience and hydrolysis-resistant thermoplastic polyurethane adhesive according to any one of claims 1 to 8, characterized in that: The method comprises the steps of uniformly mixing a polyol component, a diisocyanate component and an optional chain extender component, and then extruding the mixture through a twin-screw reaction; Preferably, the extrusion temperature is 130 to 200°C, more preferably 140 to 180°C.

10. Use of the high-resilience and hydrolysis-resistant thermoplastic polyurethane adhesive according to any one of claims 1 to 8 or the high-resilience and hydrolysis-resistant thermoplastic polyurethane adhesive prepared by the preparation method according to claim 9 in bonding PVC, fabric, leather or foam materials, especially in bonding elastic fabrics.

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