A moisture-cured polyurethane hot melt adhesive, its preparation method and use

Abstract

The application relates to a moisture-cured polyurethane hot melt adhesive and a preparation method and application thereof. The hot melt adhesive contains the reaction product of a polyisocyanate, a polyether polyol and a polycaprolactone polyol; the number average molecular weight of the polycaprolactone polyol is above 40000. The preparation method is as follows: in the presence of a protective gas, the polyether polyol and the polycaprolactone polyol are added into a reactor, the raw materials are heated to a molten flow state, then the polyisocyanate is added to fully react to obtain a reaction type polyurethane hot melt adhesive, the adhesive is sealed, packaged and stored; the moisture-cured polyurethane hot melt adhesive is used for bonding between quiet floor materials; after the adhesive is used as a bonding agent to bond the materials and is placed in a high-temperature environment, the bonding materials do not appear to be foamed or delaminated, especially when the adhesive is used for bonding quiet floors, the composite floor is lower in sound volume decibels under the condition of the same stepping or impact force.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, specifically to a moisture-curing polyurethane hot melt adhesive and its preparation method, and particularly to its application in soundproof flooring. Background Technology

[0002] Soundproof flooring is a special type of functional flooring that reduces noise and vibration while providing a comfortable feel underfoot. It is currently used in public institutions such as libraries, exhibition halls, hospitals, and government buildings. Soundproofing is achieved by laminating or filling the back of the flooring with sound-absorbing and noise-reducing materials. Types include solid wood soundproof flooring, PVC soundproof flooring, SPC soundproof flooring, and rubber flooring. Compared to internal or external grooved filling methods (CN213015190), soundproof flooring made by laminating EVA, IXPE, or PE foam sponge on the back offers advantages such as simple operation, high design flexibility, and cost-effectiveness, making it the preferred choice for major flooring manufacturers. Due to durability requirements, the soundproofing pad is generally made of low-polarity, closed-cell foam material. Using high-polarity adhesives results in large polarity differences and low bond strength. Using low-polarity adhesives, due to the low cohesive strength of the adhesive itself, also makes it difficult to guarantee the final bond strength. Furthermore, during sea transport, the temperature inside containers can reach as high as 80°C, which can easily lead to weakened adhesive strength or even delamination. Therefore, developing an adhesive suitable for bonding soundproof flooring is of great significance.

[0003] Currently, the following methods are used to prepare sound-absorbing flooring using composite sound-absorbing pads: CN208907294 U provides a method for preparing a floor with a sound-absorbing pad, in which PVC or PE hot melt adhesive is coated onto the surface of the sound-absorbing pad. The hot melt adhesive film on the surface of the sound-absorbing pad is melted using the high temperature (155-180℃) during floor calendering, and a cooling roller is provided to prevent the cushioning pad from melting. CN115216260A provides an environmentally friendly, strong-adhesion hot melt adhesive for SPC flooring sound-absorbing pads and its preparation method. Its hot melt adhesive components include mineral oil, thermoplastic elastomer, polyoxymethylene, tackifying resin, and antioxidant. Experimental tests show that it still has good adhesion at 40℃. CN213767503 U provides a sound-absorbing floor and bonding device. The bonding between the board and the sound-absorbing pad is achieved by coating the surface of the sound-absorbing pad with a heat-activated water-based polyurethane adhesive. CN116042143A provides a high-temperature resistant adhesive for composite sound-absorbing flooring and its preparation method. By adding high-melting-point thermoplastic resin and tackifying resin, the effect of no warping or bulging was achieved under the test conditions of 60℃ / 24h. Summary of the Invention

[0004] Technical Problem: The purpose of this invention is to overcome the above-mentioned defects and provide a moisture-curing polyurethane hot melt adhesive, its preparation method, and its application. When this hot melt adhesive is used as an adhesive bonding material and placed in a high-temperature environment, the adhesive material will not exhibit bubbling or delamination. Especially when used as an adhesive for soundproof flooring, the composite flooring produces a lower decibel level under the same walking or impact conditions.

[0005] Technical solution: The present invention provides a moisture-curing polyurethane hot melt adhesive containing the reaction product of polyisocyanate, polyether polyol and polycaprolactone polyol; wherein the number average molecular weight of the polycaprolactone polyol is above 40,000.

[0006] The moisture-curing polyurethane hot melt adhesive comprises the following raw materials in parts by weight:

[0007] Polyisocyanates 15-35%;

[0008] Polyether polyols 25-60%;

[0009] Polycaprolactone polyol 15-40%.

[0010] The polyisocyanate includes one or more of toluene diisocyanate, diphenylmethane diisocyanate, and their isomers and / or derivatives and / or modified polymers.

[0011] The polyether polyol includes one or a combination of polypropylene glycol polyol and polytetramethylene ether polyol, wherein the number average molecular weight of the polyether polyol is 800-2000 g / mol, preferably 800-1500 g / mol.

[0012] The polyether polyols include modified polyether polyols, which are obtained by modifying styrene and / or acrylonitrile, and the number average molecular weight of the modified polyether polyols is 800-2000 g / mol.

[0013] The number average molecular weight of the modified polyether polyol is 800–1500 g / mol.

[0014] The polycaprolactone polyol has a number-average molecular weight of 50,000 to 100,000 g / mol.

[0015] The preparation method of the moisture-curing polyurethane hot melt adhesive of the present invention is as follows: under the presence of a protective gas, polyether polyol and polycaprolactone polyol are added to a reactor, the temperature is raised to the point where the raw materials are in a molten flow state, and then polyisocyanate is added to react fully to obtain the moisture-curing polyurethane hot melt adhesive, which is then sealed, packaged and stored; the NCO mass content of the moisture-curing polyurethane hot melt adhesive is 1.5-5%.

[0016] The preparation method described herein includes the addition of a catalyst to increase the reaction rate, wherein the catalyst comprises one or a combination of two of the following: amine catalysts and metal catalysts.

[0017] The present invention relates to the application of moisture-curing polyurethane hot melt adhesive for bonding between soundproof flooring materials, including bonding between boards and sound-absorbing materials. The soundproof flooring material is obtained by applying molten moisture-curing polyurethane hot melt adhesive to one side of the flooring substrate or the sound-absorbing material and bonding the two together within the open time of the hot melt adhesive.

[0018] Beneficial effects: The moisture-curing polyurethane hot melt adhesive of the present invention has good fluidity during the application process, making it easy to apply. After curing, the product has excellent bonding strength and better temperature resistance than other adhesives. When this hot melt adhesive is used as a bonding material and placed in a high-temperature environment, the bonding material will not blister or delaminate. Especially when used as an adhesive for soundproof flooring, the composite flooring has a lower volume under the same stepping or impact conditions. Detailed Implementation

[0019] The moisture-curing polyurethane hot melt adhesive contains reaction products of polyisocyanate, polyether polyol and polycaprolactone polyol; wherein the number average molecular weight of the polycaprolactone polyol is above 40,000.

[0020] Preferably, the moisture-curing polyurethane hot melt adhesive comprises the following raw materials in parts by weight:

[0021] Polyisocyanates 15-35%;

[0022] Polyether polyols 25-60%;

[0023] Polycaprolactone polyol 15-40%;

[0024] The polyisocyanates include one or more of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and their isomers and / or derivatives and / or modified polymers.

[0025] The polyether polyols include one or a combination of polypropylene glycol polyol (PPG) and polytetramethylene ether polyol (PTMEG), wherein the number-average molecular weight (Mn) of the polyether polyols is 800–2000 g / mol, preferably 800–1500 g / mol.

[0026] Furthermore, the polyether polyol includes a modified polyether polyol, which is obtained by modification with styrene and / or acrylonitrile, and the number average molecular weight Mn of the modified polyether polyol is 800-2000 g / mol, preferably 800-1500 g / mol.

[0027] In some embodiments of the present invention, the polyether polyol includes polypropylene glycol polyol (PPG);

[0028] In other embodiments of the present invention, the modified polyether polyol includes styrene-modified polypropylene glycol polyol St-PPG, acrylonitrile-modified polypropylene glycol polyol An-PPG, and styrene-acrylonitrile-modified polypropylene glycol polyol St-An-PPG.

[0029] Preferably, the number average molecular weight of the polycaprolactone polyol PCL is 50,000 to 100,000 g / mol;

[0030] In this invention, the polycaprolactone polyol contains hydroxyl groups that are reactive to isocyanates.

[0031] Preferably, the moisture-curing polyurethane hot melt adhesive does not require the addition of tackifying resin, and the tackifying resin includes one or more of petroleum resin, rosin resin, and acrylic resin.

[0032] The moisture-curing polyurethane hot melt adhesive comprises the following preparation steps:

[0033] In the presence of a protective gas, polyether polyol and polycaprolactone polyol are added to the reactor, heated to a molten flow state, and then polyisocyanate is added to react fully to obtain reactive polyurethane hot melt adhesive, which is then sealed and stored.

[0034] The NCO content of the controlled reactive polyurethane hot melt adhesive is 1.5-5% by mass;

[0035] In this invention, the protective gas is a gas that does not participate in the reaction, such as nitrogen.

[0036] During the preparation process, a catalyst may be added to increase the reaction rate. The catalyst may include one or a combination of two of the following: amine catalysts and metal catalysts.

[0037] As an example, the moisture-curing polyurethane hot melt adhesive specifically includes the following preparation steps:

[0038] In the presence of a protective gas, polyether polyol and polycaprolactone polyol are added to a reaction vessel and heated to 100–120°C. After vacuum dehydration, the temperature is lowered to 60–90°C, polyisocyanate is added, and the temperature is further raised to 100–120°C for a full reaction of 1–3 hours. The resulting moisture-curing polyurethane hot melt adhesive is then packaged and stored.

[0039] Preferably, additives known to those skilled in the art, including antioxidants, ultraviolet absorbers, etc., can be further added to the moisture-curing polyurethane hot melt adhesive;

[0040] Preferably, the antioxidant is one or more of antioxidant 1135, antioxidant 1010, antioxidant 168, and triphenyl phosphite;

[0041] In some embodiments of the present invention, the amount of antioxidant added is less than 0.3%, calculated based on the total mass of the hot melt adhesive;

[0042] Preferably, the ultraviolet absorber is one or more of UV-326, UV-328, UV-1130, light stabilizer 292, and light stabilizer 622;

[0043] In some embodiments of the present invention, the amount of ultraviolet absorber added is less than 0.3%, calculated based on the total mass of the hot melt adhesive;

[0044] The addition of the additives is only required to avoid deterioration of the moisture-curing polyurethane hot melt adhesive of the present invention;

[0045] There are no particular limitations on the method of adding the additives. Known methods such as direct addition and mixing during the reaction process or melt blending or direct blending during subsequent processing can be used.

[0046] The aforementioned moisture-curing polyurethane hot melt adhesive is used for bonding between soundproof flooring materials, including bonding between flooring substrate and sound-absorbing material. By applying molten moisture-curing polyurethane hot melt adhesive to one side of the flooring substrate or sound-absorbing material, the two are bonded together within the open time of the hot melt adhesive to obtain soundproof flooring material.

[0047] As an example, the moisture-curing polyurethane hot melt adhesive coating step includes:

[0048] Molten, moisture-curing polyurethane hot melt adhesive is applied to the surface of the flooring substrate using a roller coating device. During the open time, sound-absorbing foam is attached to the surface of the flooring substrate. The composite board is then placed under room temperature conditions for full curing to obtain the final sound-absorbing flooring product.

[0049] The principles and features of this invention are described below with reference to specific examples. These examples are provided to facilitate a better understanding of the invention by those skilled in the art. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0050] The raw materials used in the examples and comparative examples are all commercially available:

[0051] Example 1

[0052] The moisture-curing polyurethane hot melt adhesive comprises the following raw materials in parts by weight:

[0053] MDI 16.2%;

[0054] PPG (Mn-1000) 45.9%;

[0055] PCL(Mn-80000) 37.9%;

[0056] Example 2

[0057] The moisture-curing polyurethane hot melt adhesive comprises the following raw materials in parts by weight:

[0058] MDI 23.8%;

[0059] PPG (Mn-1500) 54.3%;

[0060] PCL(Mn-80000) 21.9%;

[0061] Example 3

[0062] The moisture-curing polyurethane hot melt adhesive comprises the following raw materials in parts by weight:

[0063] MDI 25%;

[0064] PPG (Mn-1000) 60%;

[0065] PCL (Mn-50000) 15%;

[0066] Example 4

[0067] The moisture-curing polyurethane hot melt adhesive comprises the following raw materials in parts by weight:

[0068] MDI 23.8%;

[0069] PTMEG(Mn-1500) 54.3%;

[0070] PCL(Mn-80000) 21.9%;

[0071] Example 5

[0072] The moisture-curing polyurethane hot melt adhesive comprises the following raw materials in parts by weight:

[0073] MDI 27%;

[0074] PPG (Mn-1000) 56.8%;

[0075] PCL(Mn-50000) 16.2%;

[0076] Example 6

[0077] The moisture-curing polyurethane hot melt adhesive comprises the following raw materials in parts by weight:

[0078] MDI 16.2%;

[0079] St-An-PPG(Mn-1000) 45.9%;

[0080] PCL(Mn-80000) 37.9%;

[0081] Example 7

[0082] The moisture-curing polyurethane hot melt adhesive comprises the following raw materials in parts by weight:

[0083] MDI 16.2%;

[0084] PPG (Mn-2000) 45.9%;

[0085] PCL(Mn-80000) 37.9%;

[0086] Example 8

[0087] The moisture-curing polyurethane hot melt adhesive comprises the following raw materials in parts by weight:

[0088] MDI 16.2%;

[0089] PPG (Mn-3000) 45.9%;

[0090] PCL(Mn-80000) 37.9%;

[0091] Example 9

[0092] The moisture-curing polyurethane hot melt adhesive comprises the following raw materials in parts by weight:

[0093] MDI 27%;

[0094] PPG (Mn-1000) 56.8%;

[0095] PCL(Mn-50000) 16.2%;

[0096] In addition, 15% tackifying resin acrylic resin is added to the moisture-curing polyurethane hot melt adhesive, calculated based on the mass of the moisture-curing polyurethane hot melt adhesive.

[0097] Example 10

[0098] The moisture-curing polyurethane hot melt adhesive comprises the following raw materials in parts by weight:

[0099] MDI 27%;

[0100] Polyethylene glycol polyol PEG (Mn-1000) 56.8%;

[0101] PCL(Mn-50000) 16.2%;

[0102] Comparative Example 1

[0103] The moisture-curing polyurethane hot melt adhesive comprises the following raw materials in parts by weight:

[0104] MDI 16.2%;

[0105] Polybutylene adipate polyol PBA (Mn-1000) 45.9%;

[0106] PCL(Mn-80000) 37.9%;

[0107] Comparative Example 2

[0108] The moisture-curing polyurethane hot melt adhesive comprises the following raw materials in parts by weight:

[0109] MDI 16.2%;

[0110] St-An-PBA(Mn-1000) 45.9%;

[0111] PCL(Mn-80000) 37.9%;

[0112] Comparative Example 3

[0113] The moisture-curing polyurethane hot melt adhesive comprises the following raw materials in parts by weight:

[0114] MDI 16.2%;

[0115] PPG (Mn-1000) 45.9%;

[0116] PBA(Mn-80000) 37.9%;

[0117] Comparative Example 4

[0118] The moisture-curing polyurethane hot melt adhesive comprises the following raw materials in parts by weight:

[0119] MDI 27%;

[0120] PPG (Mn-1000) 56.8%;

[0121] PCL(Mn-2000) 16.2%;

[0122] The preparation steps for the above-described embodiments and comparative examples are as follows:

[0123] In the presence of nitrogen as a protective gas, the polyol is added to the reactor and heated to 115°C; after vacuum dehydration, the temperature is lowered to 75°C, polyisocyanate is added, and the temperature is further raised to 120°C for a full reaction of 1–3 hours; after cooling, the moisture-curing polyurethane hot melt adhesive is obtained and packaged for storage.

[0124] In Example 10, after all components have fully reacted, a tackifying resin is added and the mixture is cooled to obtain a moisture-curing polyurethane hot melt adhesive, which is then packaged and stored.

[0125] The moisture-curing polyurethane hot melt adhesives obtained in the above embodiments and comparative examples are used as bonding materials for soundproof flooring materials.

[0126] Molten, moisture-curing polyurethane hot melt adhesive is applied to the back of the flooring substrate using a roller coating device. During the open time, sound-absorbing foam is then attached to the back of the flooring substrate. The composite board is then placed at room temperature for 48 hours to cure, resulting in the final sound-absorbing flooring product.

[0127] The following performance tests were conducted on the obtained soundproof flooring products. The test results are shown in Table 1:

[0128] (1) Application flowability: Under the condition of heating the polyurethane hot melt adhesive to the application temperature of 130℃, observe whether the hot melt adhesive has linear flowability. The grades from high to low are good, average and poor.

[0129] (2) Bubbling: Place the silent floor sample in an 80℃ oven for 24 hours, and then observe whether there is bulging or bubbling between the foam sponge and the floor substrate.

[0130] (3) Adhesion strength: The finished silent floor was cured at 50% RH and 25℃ for 48 hours. A 200mm*30mm sample was cut and the T-type peel strength was tested.

[0131] (4) Decibel level after stepping on the floor: The finished soundproof flooring is laid on a 1m floor. 2 On the ground, the volume generated by a human weighing 50±1kg walking upright on the floor was measured using a decibel meter.

[0132] Table 1:

[0133]

Claims

1. A moisture-curing polyurethane hot melt adhesive, characterized in that... The hot melt adhesive contains the reaction products of polyisocyanate, polyether polyol and polycaprolactone polyol; the number average molecular weight of the polycaprolactone polyol is 50,000~80,000 g / mol. The moisture-curing polyurethane hot melt adhesive is composed of the following raw materials by mass fraction: Polyisocyanates 15-35%; Polyether polyols 25-60%; Polycaprolactone polyol 15-40%; The polyether polyols include one or a combination of polypropylene glycol polyols and polytetramethylene ether polyols, wherein the number average molecular weight of the polyether polyols is 1000~2000 g / mol. The moisture-curing polyurethane hot melt adhesive has an NCO content of 1.5-5% by mass.

2. The moisture-curing polyurethane hot melt adhesive according to claim 1, characterized in that, The polyisocyanate includes one or more of toluene diisocyanate, diphenylmethane diisocyanate, and their isomers.

3. The moisture-curing polyurethane hot melt adhesive according to claim 1, characterized in that, The number average molecular weight of the polyether polyol is 1000~1500 g / mol.

4. A method for preparing the moisture-curing polyurethane hot melt adhesive as described in claim 1, characterized in that, The preparation method is as follows: under the presence of a protective gas, polyether polyol and polycaprolactone polyol are added to a reactor, heated to a molten flow state, and then polyisocyanate is added to react fully to obtain a moisture-curing polyurethane hot melt adhesive, which is then sealed, packaged, and stored; the NCO content of the moisture-curing polyurethane hot melt adhesive is 1.5-5% by mass.

5. The method for preparing the moisture-curing polyurethane hot melt adhesive according to claim 4, characterized in that, The preparation method described herein includes the addition of a catalyst to increase the reaction rate, wherein the catalyst comprises one or a combination of two of the following: amine catalysts and metal catalysts.

6. An application of the moisture-curing polyurethane hot melt adhesive as described in claim 1, characterized in that, The aforementioned moisture-curing polyurethane hot melt adhesive is used for bonding between soundproof flooring materials, including bonding between boards and sound-absorbing materials. By applying molten moisture-curing polyurethane hot melt adhesive to one side of the flooring substrate or sound-absorbing material, the two are bonded together within the open time of the hot melt adhesive to obtain soundproof flooring materials.

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