Foamed polyacrylate emulsions and methods for their preparation, foamed elastomers and methods for their preparation and use

Abstract

The present application relates to a kind of foaming polyacrylate emulsion and its preparation method, foamed elastomer and its preparation method and application.The preparation raw material of the foaming polyacrylate emulsion includes 45 parts-55 parts of reaction monomer, 0.15 parts-0.35 parts of initiator, 1 part-2.75 parts of non-ionic emulsifier and 45 parts-55 parts of deionized water by mass fraction, the molecular structure formula of non-ionic emulsifier is as shown in formula (I), in formula (I), R is C12-C18 alkyl, n is 10-30 integer;Wherein, the emulsion particle size of foaming polyacrylate emulsion is 300nm-400nm, solid content is 45%-55%, and the foam height retention rate after foaming 5min is greater than or equal to 97%, the height retention rate=foam final height / foam original height.The foamed elastomer prepared by using the foaming polyacrylate emulsion of the present application has small pore size and high pore size uniformity, and does not need to use foaming agent and foam stabilizer, avoids foam stabilizer precipitation and remains on substrate, is difficult to clean, and affects use.

Description

Technical Field

[0001] This invention relates to the field of foamed materials technology, and in particular to a foamed polyacrylate emulsion and its preparation method, a foamed elastomer and its preparation method and application. Background Technology

[0002] Traditional anti-slip materials often use pressure-sensitive adhesives for adhesion. These materials suffer from drawbacks such as leaving residue after removal, poor water resistance, and environmental unfriendliness, making them unsuitable for home furnishings. Therefore, self-adhesive foamed anti-slip materials have emerged in recent years. These materials utilize the negative pressure of the foam to adhere to the substrate, leaving no residue after removal and allowing for repeated use. However, the foaming resins used in these materials typically contain large amounts of foaming agents and foam stabilizers, resulting in higher production costs. Furthermore, many foam stabilizers tend to precipitate on the foam surface, leaving residues on the substrate that are difficult to remove and prone to repeated precipitation. Summary of the Invention

[0003] Therefore, it is necessary to address the above problems by providing a foamed polyacrylate emulsion and its preparation method, a foamed elastomer and its preparation method, and its application. When preparing the foamed elastomer using the foamed polyacrylate emulsion, it is not necessary to use foaming agents and foam stabilizers, thus avoiding the precipitation and residue of foam stabilizers on the substrate, which would affect the use. Furthermore, the foamed elastomer has small pore size and high pore size uniformity.

[0004] A foaming polyacrylate emulsion, comprising, by weight, 45-55 parts of a reactive monomer, 0.15-0.35 parts of an initiator, 1-2.75 parts of a nonionic emulsifier, and 45-55 parts of deionized water, wherein the molecular structure of the nonionic emulsifier is shown in formula (I).

[0005]

[0006] In formula (Ⅰ), R is a C12 to C18 alkyl group, and n is an integer from 10 to 30;

[0007] The foaming polyacrylate emulsion has a particle size of 300nm to 400nm, a solid content of 45% to 55%, and a foam height retention rate of greater than or equal to 97% after foaming for 5 minutes. The height retention rate is defined as the final foam height divided by the original foam height.

[0008] In one embodiment, the foamed polyacrylate emulsion has a viscosity of 800 mPa·s to 1500 mPa·s at 25°C, a glass transition temperature of -30°C to -20°C, and a foaming ratio of 1:2.5 to 1:5 after mechanical foaming for 8 minutes.

[0009] In one embodiment, the reactive monomers include 20 to 23 parts of methyl acrylate, 14 to 17 parts of butyl acrylate, 8 to 10 parts of isooctyl acrylate, 1 to 1.5 parts of acrylonitrile, 1 to 2 parts of acrylic acid, and 1 to 1.5 parts of hydroxyethyl acrylate.

[0010] A method for preparing a foaming polyacrylate emulsion as described above includes the following steps:

[0011] The reactive monomers and a portion of nonionic emulsifiers are emulsified in deionized water to obtain a first preemulsion, wherein the total mass of the nonionic emulsifiers is 0.5% to 1% of the total mass of the reactive monomers;

[0012] The first preemulsion is divided into emulsion A and emulsion B, wherein emulsion A accounts for 3% of the mass of the first preemulsion, and the remaining amount of the nonionic emulsifier is added to emulsion B to obtain emulsion C;

[0013] A portion of the initiator is added to emulsion A for initiation, then the temperature is raised and emulsion C and the remaining amount of initiator are added to obtain a foaming polyacrylate emulsion. In the process of adding a portion of the initiator to emulsion A for initiation, the mass of the initiator accounts for 1 / 4 to 1 / 3 of the total mass of the initiator.

[0014] A foamed elastomer, by mass parts, comprises 80 to 90 parts of the foaming polyacrylate emulsion, 10 to 20 parts of inorganic filler, and 0.5 to 2.0 parts of crosslinking agent, wherein the foamed elastomer has a pore size of 50 μm to 80 μm and a foam thickness of 1 mm to 5 mm.

[0015] In one embodiment, the inorganic filler is selected from at least one of kaolin, titanium dioxide, aluminum hydroxide, or zinc oxide;

[0016] And / or, the crosslinking agent is selected from isocyanates and / or aziridines.

[0017] A method for preparing the foamed elastomer includes the following steps:

[0018] A mixed slurry is obtained by mixing the foamed polyacrylate emulsion, inorganic filler, and crosslinking agent as described above.

[0019] The mixed slurry is mechanically foamed to obtain a foamed slurry;

[0020] The foaming slurry is placed on the surface of the substrate and dried to obtain a foamed elastomer.

[0021] In one embodiment, in the step of mechanically foaming the mixed slurry to obtain foamed slurry, the foaming ratio of the foaming machine is 1:2 to 1:4.

[0022] In one embodiment, the drying process involves a temperature of 120°C to 160°C and a time of 4 to 5 minutes.

[0023] The application of the foamed elastomer described above in the preparation of anti-slip materials.

[0024] The foaming polyacrylate emulsion provided by this invention has an emulsion particle size of 300nm to 400nm. Compared with small-diameter particles, the large-diameter particles of this invention have a smaller specific surface area. Simultaneously, by employing a nonionic emulsifier with a special structure, less nonionic emulsifier is adsorbed on the surface of the large-diameter particles, resulting in more free nonionic emulsifier in the emulsion system. This reduces the surface tension of the emulsion and significantly improves its foaming performance. Furthermore, due to the excellent foam-stabilizing properties of the nonionic emulsifier with a special structure, the foam height retention rate after 5 minutes of foaming can reach greater than or equal to 97%. Therefore, when preparing foamed elastomers from the high-foaming polyacrylate emulsion, the foamed elastomers have small pore sizes and high pore size uniformity, and do not require the use of foaming agents and foam stabilizers. This eliminates the problem of foam stabilizer precipitation on the foam layer surface, resulting in no foam stabilizer residue after removal of the foamed elastomer. It also exhibits excellent resilience, negative pressure adsorption performance, and soap-resistant properties. Attached Figure Description

[0025] Figure 1 This is a particle size distribution diagram of the foamed polyacrylate emulsion seeds in Example 1;

[0026] Figure 2 This is a particle size distribution diagram of the foamed polyacrylate emulsion in Example 1;

[0027] Figure 3 The infrared spectrum of the foamed polyacrylate emulsion of Example 1 is shown below.

[0028] Figure 4 Differential scanning calorimetry (DSC) of the foamed polyacrylate emulsion of Example 1;

[0029] Figure 5 This is a scanning electron microscope image of the interior of the foamed elastomer in Example 1. Detailed Implementation

[0030] To facilitate understanding of the present invention, it will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. Rather, these embodiments or examples are provided to make the disclosure of the present invention more thorough and complete.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments or examples only and is not intended to limit the invention. The optional scope of the term "and / or" as used herein includes any one of two or more of the related listed items, as well as any and all combinations of the related listed items, including any two related listed items, any more related listed items, or a combination of all related listed items.

[0032] This invention provides a foaming polyacrylate emulsion, wherein the raw materials for preparing the foaming polyacrylate emulsion, by weight, include 45 to 55 parts of reactive monomer, 0.15 to 0.35 parts of initiator, 1 to 2.75 parts of nonionic emulsifier, and 45 to 55 parts of deionized water. The molecular structure of the nonionic emulsifier is shown in formula (I).

[0033]

[0034] In formula (Ⅰ), R is a C12 to C18 alkyl group, and n is an integer from 10 to 30;

[0035] The foaming polyacrylate emulsion has a particle size of 300nm to 400nm, a solid content of 45% to 55%, and a foam height retention rate of greater than or equal to 97% after foaming for 5 minutes. The height retention rate is defined as the final foam height divided by the original foam height.

[0036] The foaming polyacrylate emulsion of this invention has a particle size of 300nm to 400nm. Compared with small-particle-size particles, the large-particle-size particles of the emulsion have a smaller specific surface area. At the same time, by using a nonionic emulsifier with a special structure, less nonionic emulsifier is adsorbed on the surface of the large-particle-size particles, and more nonionic emulsifier is free in the emulsion system, thereby reducing the surface tension of the emulsion and significantly improving the foaming performance. Furthermore, since the nonionic emulsifier with the special structure forms a stable thin film layer at the foam interface through long alkyl chains without the addition of foam stabilizers, it can effectively stabilize foaming by reducing surface tension and preventing foam fusion, allowing the foam to maintain its shape and stability for a long time. The foam height retention rate can reach greater than or equal to 97% after 5 minutes of foaming. At the same time, the solid content of the foaming polyacrylate emulsion is limited to 45% to 55% to further improve the foam stabilization performance. Therefore, the foaming polyacrylate emulsion has excellent foaming properties and excellent foam stabilizing properties. Consequently, when the high foaming polyacrylate emulsion is used to prepare foamed elastomers, it is not necessary to use foaming agents and foam stabilizers, and the foamed elastomers have small pore sizes and high pore size uniformity.

[0037] Specifically, when tested at 25°C, the initial foam height of the foaming polyacrylate emulsion was 10-11 cm, and it remained at 10-11 cm after 5 minutes, indicating that the emulsion has excellent foaming and foam stabilizing properties.

[0038] Optionally, the foamed polyacrylate emulsion has a viscosity of 800 mPa.s to 1500 mPa.s at 25°C, a glass transition temperature of -30°C to -20°C, and a foaming ratio of 1:2.5 to 1:5 after mechanical foaming for 8 minutes.

[0039] Optionally, n in the nonionic emulsifier is preferably 10, 20, or 30, and / or R is preferably a C15-C17 alkyl group, thereby enabling the nonionic emulsifier to have superior foam stabilizing properties; and when preparing foamed elastomers from the foaming polyacrylate emulsion, the use of the nonionic emulsifier can further improve the salt resistance of the emulsion system, and when subsequently compounded with inorganic fillers, it can ensure the stable dispersion of the inorganic fillers, thereby preparing foamed elastomers with more uniform and superior performance.

[0040] Optionally, the reactive monomers include 20 to 23 parts of methyl acrylate, 14 to 17 parts of butyl acrylate, 8 to 10 parts of isooctyl acrylate, 1 to 1.5 parts of acrylonitrile, 1 to 2 parts of acrylic acid, and 1 to 1.5 parts of hydroxyethyl acrylate.

[0041] Optionally, the initiator is selected from at least one of sodium persulfate, ammonium persulfate, or potassium persulfate.

[0042] The present invention also provides a method for preparing the foaming polyacrylate emulsion, comprising the following steps:

[0043] S11, the reactive monomer and a portion of the nonionic emulsifier are emulsified in deionized water to obtain a first pre-emulsion, wherein the total mass of the nonionic emulsifier is 0.5% to 1% of the total mass of the reactive monomer;

[0044] S12, the first pre-emulsion is divided into emulsion A and emulsion B, wherein emulsion A accounts for 3% of the mass of the first pre-emulsion, and the remaining amount of the nonionic emulsifier is added to emulsion B to obtain emulsion C;

[0045] S13, a portion of the initiator is added to the emulsion A for initiation, then the temperature is raised and the emulsion C and the remaining amount of initiator are added to obtain a foaming polyacrylate emulsion, wherein, during the process of adding a portion of the initiator to the emulsion A for initiation, the mass of the initiator accounts for 1 / 4 to 1 / 3 of the total mass of the initiator.

[0046] In step S11, the order of adding monomers and nonionic emulsifiers is not limited. Preferably, the nonionic emulsifier is added to deionized water first, and then the reactive monomer is added and stirred for emulsification. The emulsification time is preferably 30 min to 40 min.

[0047] In step S12, the amount of the remaining nonionic emulsifier added to emulsion B is greater than the amount of nonionic emulsifier added to the first pre-emulsion, and the sum of the amounts of nonionic emulsifier added to the first pre-emulsion is 1 to 2.75 parts. The subsequent addition of a large amount of nonionic emulsifier to emulsion B can further ensure the stability of latex particles during the continuous growth process.

[0048] In step S13, emulsion A is placed in a flask purged with nitrogen gas, and 0.037 to 0.116 parts of initiator are added at 76°C to 80°C to initiate the reaction. Since the amount of nonionic emulsifier in emulsion A is very small, large-diameter seeds with a size of 200 nm to 250 nm can be formed in emulsion A. Then the temperature is raised to 82°C to 84°C, and emulsion C and the remaining amount of initiator are added. On this basis, the particles continue to grow into colloidal particles with a diameter of 300 nm to 400 nm.

[0049] Because large-diameter colloidal particles adsorb less nonionic emulsifier on their surface, there is more nonionic emulsifier free in the emulsion system. As a result, a large amount of nonionic emulsifier is free in the emulsion system in the foaming polyacrylate emulsion, which reduces the surface tension of the emulsion and thus improves the foaming performance of the emulsion. The surface tension is preferably 25mN / m to 35mN / m.

[0050] Specifically, there are no restrictions on the method of adding emulsion C and the remaining amount of initiator, but it is preferred to add them dropwise. The dropwise addition time is preferably 3h to 4h, and the emulsion is discharged after being kept warm for 30min to 50min to obtain foamed polyacrylate emulsion.

[0051] The present invention also provides a foamed elastomer, wherein, by mass parts, the raw materials for preparing the foamed elastomer include 80 to 90 parts of the foamed polyacrylate emulsion, 10 to 20 parts of inorganic filler, and 0.5 to 2.0 parts of crosslinking agent.

[0052] Foamed elastomers are prepared from the foamed polyacrylate emulsion. Due to the excellent foam-stabilizing ability of the nonionic emulsifier, the resulting foamed elastomers have small pore sizes (50 μm to 80 μm), high pore size uniformity, and foam thicknesses of 1 mm to 5 mm. Furthermore, since no foaming agent or foam stabilizer is required during the preparation process, there is no issue of foam stabilizer precipitation on the foam surface. In addition, the raw materials for preparing the foamed elastomers are simple, and they still exhibit excellent resilience properties without the use of elastomers such as polyurethane.

[0053] Optionally, the foamed elastomer is at 1 kg / cm². 2 After being held under pressure for 1 minute, the pressure is removed, and the foam can quickly recover within 5 seconds; and / or, the foamed elastomer can be vertically attached to glass without the use of additional adhesive, and can suspend an object with a weight equivalent to 5 times its own weight without falling off within 24 hours; and / or, the negative pressure adsorption capacity of the foamed elastomer does not decrease after being soaped 30 times at 40°C.

[0054] Optionally, the inorganic filler includes at least one of kaolin, titanium dioxide, aluminum hydroxide, or zinc oxide, preferably a dispersion of inorganic filler, thereby forming secondary valence forces with the molecular chains of the foamed elastomer to enhance the rigidity of the foamed elastomer, change its viscoelastic state, and thus obtain a foamed elastomer with excellent foaming performance.

[0055] Optionally, the crosslinking agent can generate crosslinks within the foamed elastomer, forming a three-dimensional interpenetrating network structure, thereby improving the strength of the foamed elastomer and giving the foam layer a certain degree of elasticity. Preferably, the crosslinking agent includes isocyanates and / or aziridines, and the amount of the crosslinking agent is preferably 1.5 to 1.8 parts, so that the foamed elastomer has a suitable degree of crosslinking and foam layer elasticity, and excellent soap-washing resistance.

[0056] The present invention also provides a method for preparing a foamed elastomer, comprising the following steps:

[0057] S21, a mixed slurry is obtained by mixing foamed polyacrylate emulsion, inorganic filler and crosslinking agent;

[0058] S22, the mixed slurry is mechanically foamed to obtain a foamed slurry;

[0059] S23, the foaming slurry is placed on the surface of the substrate and dried to obtain a foamed elastomer.

[0060] In step S22, the mixed slurry can be placed in a foaming machine for mechanical foaming, and then extruded after reaching a set foaming ratio. The foaming ratio of the foaming machine is preferably 1:2 to 1:4, so as to obtain a foamed elastomer with better foaming performance.

[0061] In step S23, during the drying process, the drying temperature is preferably 120℃~160℃, and the drying time is preferably 4min~5min. More preferably, drying at 120℃~140℃ for 3min and then drying at 140℃~160℃ for 2min further enables the molecular chains in the foamed elastomer to be fully cross-linked and forms more uniform small bubbles in the foamed elastomer, and allows for thorough drying.

[0062] Optionally, the substrate is preferably an elastomer base fabric, and more preferably at least one of nonwoven fabric, low-elasticity yarn, or mesh fabric.

[0063] The present invention also provides an application of the foamed elastomer described above in the preparation of anti-slip materials, such as anti-slip mats, car floor mats, sofa cushions, backrests, etc.

[0064] The following specific examples will further illustrate the foamed polyacrylate emulsion and its preparation method, the foamed elastomer and its preparation method, and its application.

[0065] Example 1

[0066] A semi-continuous method was used to prepare foamed polyacrylate emulsion: First, 20 parts of methyl acrylate, 15 parts of butyl acrylate, 8 parts of isooctyl acrylate, 1 part of acrylonitrile, 2 parts of acrylic acid, 1 part of hydroxyethyl acrylate and 0.36 parts of nonionic emulsifier were added to 45 parts of deionized water solution and stirred and emulsified for 30 min to obtain the first pre-emulsion. The molecular formula of the nonionic emulsifier is shown in formula (Ⅰ), where R is a C15 alkyl group and n is 10.

[0067] The first preemulsion was divided into emulsion A and emulsion B, with emulsion A accounting for 3% of the mass of the first preemulsion. 1.48 parts of nonionic emulsifier were added to emulsion B to obtain emulsion C. Emulsion A was placed in a flask purged with nitrogen and heated to 78°C. 0.06 parts of sodium persulfate aqueous solution were added to initiate seed formation. The temperature was then raised to 84°C, and emulsion C and 0.12 parts of sodium persulfate aqueous solution were added dropwise to the seeds over a period of 3 hours. After maintaining the temperature for 30 minutes, the mixture was cooled and discharged to obtain a foamed polyacrylate emulsion.

[0068] The foaming polyacrylate emulsion in this embodiment has a solid content of 53%, a viscosity of 1000 mPa·s at 25°C, a glass transition temperature of -25°C, a foaming ratio of 1:4.8 after mechanical foaming for 8 minutes, an initial foam height of 10.7 cm at 25°C, and remains at 10.7 cm after 5 minutes.

[0069] The particle size distribution diagram of the foamed polyacrylate emulsion seeds in this embodiment is as follows: Figure 1 As shown, the particle size distribution of the foamed polyacrylate emulsion in this embodiment is as follows. Figure 2 As shown, the infrared spectrum of the foamed polyacrylate emulsion in this embodiment is as follows. Figure 3 As shown, the differential scanning calorimetry (DSC) chart of the foamed polyacrylate emulsion in this embodiment is as follows: Figure 4 As shown.

[0070] Take 90 parts of foaming polyacrylate emulsion, add 10 parts of kaolin dispersion, 0.5 parts of aziridine, and 1 part of isocyanate, and mechanically stir until homogeneous to obtain a mixed slurry. Transfer the mixed slurry to a foaming machine with a foaming ratio of 1:3 to obtain a foamed slurry. Evenly coat the foamed slurry onto a nonwoven fabric, bake at 120°C for 3 minutes, then raise the temperature to 150°C and bake for another 2 minutes to obtain a foamed elastomer. The scanning electron microscope image of the interior of the foamed elastomer in this embodiment is shown below. Figure 5 As shown, the pore size is 50μm~80μm, the average pore size is 60μm, and the bubble thickness is 5mm.

[0071] The performance test results of the foamed elastomer in this embodiment are shown in Table 1.

[0072] Example 2

[0073] A semi-continuous method was used to prepare foamed polyacrylate emulsion: First, 23 parts of methyl acrylate, 14 parts of butyl acrylate, 9 parts of isooctyl acrylate, 1.5 parts of acrylonitrile, 1 part of acrylic acid, 1 part of hydroxyethyl acrylate and 0.4 parts of nonionic emulsifier were added to 45 parts of deionized water solution and stirred and emulsified for 35 min to obtain the first pre-emulsion. The molecular formula of the nonionic emulsifier is shown in formula (Ⅰ), where R is a C16 alkyl group and n is 20.

[0074] The first preemulsion was divided into emulsion A and emulsion B, with emulsion A accounting for 3% of the mass of the first preemulsion. 1.58 parts of nonionic emulsifier were added to emulsion B to obtain emulsion C. Emulsion A was placed in a flask purged with nitrogen and heated to 78°C. 0.1 parts of sodium persulfate aqueous solution were added to initiate seed formation. The temperature was then raised to 84°C, and emulsion C and 0.2 parts of sodium persulfate aqueous solution were added dropwise to the seeds over a period of 4 hours. After maintaining the temperature for 40 minutes, the mixture was cooled and discharged to obtain a foamed polyacrylate emulsion.

[0075] The foaming polyacrylate emulsion in this embodiment has a solid content of 52%, a viscosity of 1100 mPa·s at 25°C, a glass transition temperature of -26°C, a foaming ratio of 1:4.7 after mechanical foaming for 8 minutes, an initial foam height of 10.8 cm at 25°C, and a height of 10.5 cm after 5 minutes.

[0076] Take 85 parts of foamed polyacrylate emulsion, add 15 parts of titanium dioxide dispersion, 1 part of aziridine, and 0.5 parts of isocyanate, and mechanically stir until homogeneous to obtain a mixed slurry. Transfer the mixed slurry to a foaming machine with a foaming ratio of 1:3 to obtain a foamed slurry. Evenly coat the foamed slurry onto a nonwoven fabric, bake it in an oven at 120°C for 3 minutes, then raise the temperature to 150°C and bake for another 2 minutes to obtain a foamed elastomer. The pore size of the foamed elastomer in this embodiment is 50μm to 80μm, the average pore size is 65μm, and the foam thickness is 5mm.

[0077] The performance test results of the foamed elastomer in this embodiment are shown in Table 1.

[0078] Example 3

[0079] A semi-continuous method was used to prepare foamed polyacrylate emulsion: First, 20 parts of methyl acrylate, 16 parts of butyl acrylate, 8 parts of isooctyl acrylate, 1 part of acrylonitrile, 2 parts of acrylic acid, 1 part of hydroxyethyl acrylate and 0.43 parts of nonionic emulsifier were added to 55 parts of deionized water solution and stirred and emulsified for 40 min to obtain the first pre-emulsion. The molecular formula of the nonionic emulsifier is shown in formula (Ⅰ), where R is a C15 alkyl group and n is 30.

[0080] The first pre-emulsion was divided into emulsion A and emulsion B, with emulsion A accounting for 3% of the mass of the first pre-emulsion. 1.73 parts of nonionic emulsifier were added to emulsion B to obtain emulsion C. Emulsion A was placed in a flask purged with nitrogen and heated to 78°C. 0.1 parts of sodium persulfate aqueous solution were added to initiate seed formation. The temperature was then raised to 84°C, and emulsion C and 0.2 parts of sodium persulfate aqueous solution were added dropwise to the seed over a period of 3 hours. After maintaining the temperature for 50 minutes, the mixture was cooled and discharged to obtain a foamed polyacrylate emulsion.

[0081] The foaming polyacrylate emulsion in this embodiment has a solid content of 46.5%, a viscosity of 900 mPa·s at 25°C, a glass transition temperature of -27°C, a foaming ratio of 1:5 after mechanical foaming for 8 minutes, an initial foam height of 10.8 cm at 25°C, and still maintains 10.6 cm after 5 minutes.

[0082] Take 80 parts of foamed polyacrylate emulsion, add 20 parts of aluminum hydroxide dispersion, 1.2 parts of aziridine, and 0.5 parts of isocyanate, and mechanically stir until homogeneous to obtain a mixed slurry. Transfer the mixed slurry to a foaming machine with a foaming ratio of 1:3 to obtain a foamed slurry. Evenly coat the foamed slurry onto a nonwoven fabric, bake it in an oven at 120°C for 3 minutes, then raise the temperature to 150°C and bake for another 2 minutes to obtain a foamed elastomer. The pore size of the foamed elastomer in this embodiment is 50μm to 80μm, the average pore size is 64μm, and the foam thickness is 4.8mm.

[0083] The performance test results of the foamed elastomer in this embodiment are shown in Table 1.

[0084] Example 4

[0085] The difference between Example 4 and Example 1 is that the molecular formula of the nonionic emulsifier is shown in Formula (Ⅰ), where R is a C17 alkyl group and n is 15.

[0086] The foaming polyacrylate emulsion in this embodiment has a solid content of 53%, a viscosity of 1000 mPa·s at 25°C, a glass transition temperature of -25°C, a foaming ratio of 1:4.8 after mechanical foaming for 8 minutes, an initial foam height of 10.8 cm at 25°C, and a height of 10.7 cm after 5 minutes.

[0087] The foamed elastomer in this embodiment has a pore size of 50μm to 80μm, an average pore size of 63μm, and a foam thickness of 4.8mm.

[0088] The performance test results of the foamed elastomer in this embodiment are shown in Table 1.

[0089] Example 5

[0090] The difference between Example 5 and Example 1 is that the mass of the nonionic emulsifier in the first pre-emulsion is 0.47 parts.

[0091] The foaming polyacrylate emulsion in this embodiment has a solid content of 53%, a viscosity of 1000 mPa·s at 25°C, a glass transition temperature of -25°C, a foaming ratio of 1:5 after mechanical foaming for 8 minutes, an initial foam height of 10.9 cm at 25°C, and still maintains 10.8 cm after 5 minutes.

[0092] The foamed elastomer in this embodiment has a pore size of 50μm to 80μm, an average pore size of 62μm, and a foam thickness of 5mm.

[0093] The performance test results of the foamed elastomer in this embodiment are shown in Table 1.

[0094] Comparative Example 1

[0095] The difference between Comparative Example 1 and Example 1 is that: 0.36 parts of sodium dodecyl sulfate were added to obtain a first preemulsion, and the first preemulsion was divided into emulsion A and emulsion B. Emulsion A accounted for 3% of the mass of the first preemulsion, and 1.48 parts of sodium dodecyl sulfate were added to emulsion B to obtain emulsion C.

[0096] The foamed polyacrylate emulsion in this comparative example has a solid content of 53%, a viscosity of 1020 mPa·s at 25°C, a glass transition temperature of -25°C, a foaming ratio of 1:4.5 after mechanical foaming for 8 minutes, an initial foam height of 10.5 cm at 25°C, and a height of 9.5 cm after 5 minutes.

[0097] The foamed elastomer in this comparative example has a pore size of 50μm to 100μm, an average pore size of 85μm, and a foam thickness of 4.5mm.

[0098] The performance test results of the foamed elastomer in this comparative example are shown in Table 1.

[0099] Comparative Example 2

[0100] The difference between Comparative Example 2 and Example 1 is that: 0.36 parts of sodium fatty alcohol polyoxyethylene ether sulfate were added to obtain a first preemulsion, and the first preemulsion was divided into emulsion A and emulsion B. Emulsion A accounted for 3% of the mass of the first preemulsion, and 1.48 parts of sodium fatty alcohol polyoxyethylene ether sulfate were added to emulsion B to obtain emulsion C.

[0101] The foamed polyacrylate emulsion in this comparative example has a solid content of 53%, a viscosity of 980 mPa·s at 25°C, a glass transition temperature of -25°C, a foaming ratio of 1:4.8 after mechanical foaming for 8 minutes, an initial foam height of 10.6 cm at 25°C, and a height of 8.7 cm after 5 minutes.

[0102] The foamed elastomer in this comparative example has a pore size of 50μm to 100μm, an average pore size of 95μm, and a foam thickness of 4.9mm.

[0103] The performance test results of the foamed elastomer in this comparative example are shown in Table 1.

[0104] Comparative Example 3

[0105] The difference between Comparative Example 3 and Example 1 is that the molecular structure of the nonionic emulsifier is shown in Formula (Ⅰ), where R is C20 and n is 5.

[0106] The foamed polyacrylate emulsion in this comparative example has a solid content of 53%, a viscosity of 1080 mPa·s at 25°C, a glass transition temperature of -25°C, a foaming ratio of 1:4.7 after mechanical foaming for 8 minutes, an initial foam height of 10.8 cm at 25°C, and a height of 9 cm after 5 minutes.

[0107] The foamed elastomer in this comparative example has a pore size of 50μm to 100μm, an average pore size of 92μm, and a foam thickness of 4mm.

[0108] The performance test results of the foamed elastomer in this comparative example are shown in Table 1.

[0109] Comparative Example 4

[0110] The difference between Comparative Example 4 and Example 1 is that the molecular structure of the nonionic emulsifier is shown in Formula (Ⅰ), where R is C11 and n is 35.

[0111] The foamed polyacrylate emulsion in this comparative example has a solid content of 53%, a viscosity of 990 mPa·s at 25°C, a glass transition temperature of -25°C, a foaming ratio of 1:4.8 after mechanical foaming for 8 minutes, an initial foam height of 10.5 cm at 25°C, and a height of 9 cm after 5 minutes.

[0112] The foamed elastomer in this comparative example has a pore size of 50μm to 100μm, an average pore size of 90μm, and a foam thickness of 4.6mm.

[0113] The performance test results of the foamed elastomer in this comparative example are shown in Table 1.

[0114] Comparative Example 5

[0115] The difference between Comparative Example 5 and Example 1 is that the raw materials for preparing the foamed elastomer contain 100 parts of foaming polyacrylate emulsion, 1.5 parts of aziridine, and 0.5 parts of isocyanate.

[0116] The foamed elastomer in this comparative example has a pore size of 50μm to 120μm, an average pore size of 100μm, and a foam thickness of 5mm.

[0117] The performance test results of the foamed elastomer in this comparative example are shown in Table 1.

[0118] Comparative Example 6

[0119] The difference between Comparative Example 6 and Example 1 is that the raw materials for preparing the foamed elastomer contain 2 parts of aziridine and 1 part of isocyanate.

[0120] The foamed elastomer in this comparative example has a pore size of 50μm to 120μm, an average pore size of 95μm, and a foam thickness of 5mm.

[0121] The performance test results of the foamed elastomer in this comparative example are shown in Table 1.

[0122] Comparative Example 7

[0123] The difference between Comparative Example 7 and Example 1 is that the foaming polyacrylate emulsion was prepared by a semi-continuous method: First, 20 parts of methyl acrylate, 15 parts of butyl acrylate, 8 parts of isooctyl acrylate, 1 part of acrylonitrile, 1 part of acrylic acid, 1 part of hydroxyethyl acrylate and 1.84 parts of nonionic emulsifier were added to 45 parts of aqueous solution and stirred and emulsified for 30 min to obtain the first pre-emulsion. The molecular structure of the nonionic emulsifier is shown in Formula (I), where R is a C15 alkyl group and n is 10.

[0124] The first pre-emulsion was divided into emulsion A and emulsion B, with emulsion A accounting for 3% of the mass of the first pre-emulsion. Emulsion A was placed in water at 78°C, and 0.06 parts of sodium persulfate aqueous solution were added to initiate the formation of seeds. Then, the temperature was raised to 82°C, and emulsion B and 0.12 parts of sodium persulfate aqueous solution were added dropwise to the seeds over a period of 3 hours. After keeping the temperature warm for 30 minutes, the material was cooled and discharged to obtain foamed polyacrylate emulsion.

[0125] The foamed polyacrylate emulsion in this comparative example has a solid content of 53%, a viscosity of 1000 mPa·s at 25°C, a glass transition temperature of -25°C, a foaming ratio of 1:4 after mechanical foaming for 8 minutes, an initial foam height of 10 cm at 25°C, and a height of 9 cm after 5 minutes.

[0126] The foamed elastomer in this comparative example has a pore size of 50μm to 100μm, an average pore size of 89μm, and a foam thickness of 5mm.

[0127] The performance test results of the foamed elastomer in this comparative example are shown in Table 1.

[0128] Comparative Example 8

[0129] The difference between Comparative Example 8 and Example 1 is that the mass of the nonionic emulsifier is 2.5% of the total mass of the monomers.

[0130] The foamed polyacrylate emulsion in this comparative example has a solid content of 53%, a viscosity of 900 mPa·s at 25°C, a glass transition temperature of -25°C, a foaming ratio of 1:4 after mechanical foaming for 8 minutes, an initial foam height of 10 cm at 25°C, and a height of 8.5 cm after 5 minutes.

[0131] The foamed elastomer in this comparative example has a pore size of 50μm to 120μm, an average pore size of 105μm, and a foam thickness of 4.7mm.

[0132] The performance test results of the foamed elastomer in this comparative example are shown in Table 1.

[0133] The testing standards for foamed elastomers in the above embodiments and comparative examples are as follows:

[0134] Resilience performance: The foamed elastomer at 1kg / cm 2 After maintaining the pressure for 1 minute, the recovery time t of the foamed elastomer is tested. A rapid recovery of t≤5s is considered excellent resilience, a recovery of 5s<t≤30s is considered good resilience, and a recovery of 30s<t≤60s is considered poor resilience.

[0135] Negative pressure adsorption performance: The foamed elastomer is vertically attached to the glass, and a weight 5 times its own weight is suspended. The time t it takes for the weight to fall off is tested. If the weight does not fall off after t ≥ 24h, the adsorption performance is considered excellent; if it does not fall off after 18h ≤ t < 24h, the adsorption performance is considered good; and if it does not fall off after 0h ≤ t < 18h, the adsorption performance is considered poor.

[0136] Soap washing resistance: The foamed elastomer is soaped at 40℃, and the number of soap washing cycles N is tested. Excellent soap washing resistance is defined as no decrease in negative pressure adsorption capacity after N≥30 cycles, good soap washing resistance is defined as no decrease in negative pressure adsorption capacity after 20≤N<30 cycles, and poor soap washing resistance is defined as no decrease in negative pressure adsorption capacity after 1≤N<20 cycles.

[0137] Table 1

[0138]

[0139]

[0140] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0141] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A foaming polyacrylate emulsion, characterized in that, The raw materials for preparing the foaming polyacrylate emulsion, by mass parts, include 45 to 55 parts of reactive monomer, 0.15 to 0.35 parts of initiator, 1 to 2.75 parts of nonionic emulsifier, and 45 to 55 parts of deionized water. The molecular structure of the nonionic emulsifier is shown in formula (I). Equation (Ⅰ), In formula (Ⅰ), R is a C12~C18 alkyl group, and n is an integer from 10 to 30; The foaming polyacrylate emulsion has a particle size of 300nm~400nm, a solid content of 45%~55%, and a foam height retention rate of greater than or equal to 97% after foaming for 5 minutes. The height retention rate is defined as the final foam height / the original foam height. The reactive monomers include 20 to 23 parts of methyl acrylate, 14 to 17 parts of butyl acrylate, 8 to 10 parts of isooctyl acrylate, 1 to 1.5 parts of acrylonitrile, 1 to 2 parts of acrylic acid, and 1 to 1.5 parts of hydroxyethyl acrylate. The method for preparing the foaming polyacrylate emulsion includes the following steps: The reactive monomers and a portion of a nonionic emulsifier are emulsified in deionized water to obtain a first pre-emulsion, wherein the total mass of the nonionic emulsifier is 0.5% to 1% of the total mass of the reactive monomers; The first preemulsion is divided into emulsion A and emulsion B, wherein emulsion A accounts for 3% of the mass of the first preemulsion, and the remaining amount of the nonionic emulsifier is added to emulsion B to obtain emulsion C; A portion of the initiator is added to emulsion A for initiation, then the temperature is raised and emulsion C and the remaining amount of initiator are added to obtain a foaming polyacrylate emulsion. In the process of adding a portion of the initiator to emulsion A for initiation, the mass of the initiator accounts for 1 / 4 to 1 / 3 of the total mass of the initiator.

2. The foaming polyacrylate emulsion according to claim 1, characterized in that, The foamed polyacrylate emulsion has a viscosity of 800 mPa·s to 1500 mPa·s at 25°C, a glass transition temperature of -30°C to -20°C, and a foaming ratio of 1:2.5 to 1:5 after mechanical foaming for 8 minutes.

3. A foamed elastomer, characterized in that, The raw materials for preparing the foamed elastomer, by mass parts, include 80 to 90 parts of the foaming polyacrylate emulsion as described in any one of claims 1 to 2, 10 to 20 parts of inorganic filler, and 0.5 to 2.0 parts of crosslinking agent. The foamed elastomer has a pore size of 50 μm to 80 μm and a foam thickness of 1 mm to 5 mm.

4. The foamed elastomer according to claim 3, characterized in that, The inorganic filler is selected from at least one of kaolin, titanium dioxide, aluminum hydroxide or zinc oxide; And / or, the crosslinking agent is selected from isocyanates and / or aziridines.

5. A method for preparing a foamed elastomer as described in claim 3 or 4, characterized in that, Includes the following steps: A mixed slurry is obtained by mixing the foaming polyacrylate emulsion as described in any one of claims 1 to 2, the inorganic filler, and the crosslinking agent. The mixed slurry is mechanically foamed to obtain a foamed slurry; The foaming slurry is placed on the surface of the substrate and dried to obtain a foamed elastomer.

6. The method for preparing the foamed elastomer according to claim 5, characterized in that, In the step of mechanically foaming the mixed slurry to obtain foamed slurry, the foaming ratio of the foaming machine is 1:2 to 1:

4.

7. The method for preparing the foamed elastomer according to claim 6, characterized in that, In the drying process, the temperature is 120℃~160℃ and the time is 4min~5min.

8. The use of a foamed elastomer as described in claim 3 or 4 in the preparation of anti-slip materials.

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