Wear-resistant flame-retardant transparent polyurethane material and preparation method thereof

Abstract

The invention discloses a wear-resistant flame-retardant transparent polyurethane material and a preparation method thereof. The wear-resistant flame-retardant transparent polyurethane material is prepared from the following components in parts by weight: 75 to 95.5 parts of polyurethane elastomer, 2 to 15 parts of dimethyl methylphosphonate, 1 to 3 parts of polycarbodiimide, 1 to 5 parts of quenching agent tri (2-chloroethyl) phosphate and 0.3 to 2 parts of curing chain extender. The flame retardant property of the TPU is improved by adding the DMMP flame retardant, DMMP is modified by adding the polycarbodiimide, the activity of phosphorus oxygen groups and ester groups is reduced, and the influence that the TPU is promoted to be degraded and hydrolyzed when the DMMP flame retardant is added into the TPU is solved; tCEP is added into hydrolysis-resistant DMMP, so that TPU combustion flames can be quickly extinguished, and the TPU can drop without flames; and through the synergistic effect of the modified DMMP and the curing chain extender, solid-state chain extension is performed on the TPU, so that the hydrolysis resistance and wear resistance of the TPU are further improved.

Description

Technical Field

[0001] The invention relates to the field of polymer materials, and more specifically to a wear-resistant, flame-retardant, transparent polyurethane material and a preparation method thereof. Background Art

[0002] Thermoplastic polyurethane elastomer (TPU) is a polymer material formed by the reaction and polymerization of diisocyanate molecules such as diphenylmethane diisocyanate or toluene diisocyanate and macromolecular polyols and low molecular polyols. TPU products have outstanding load-bearing capacity, impact resistance and shock absorption performance and have been widely used.

[0003] At present, in the preparation process using the blending method, transparent flame-retardant TPU is developed by mixing various raw materials by the blending method, and thermoplastic polyurethane elastomer and phosphorus flame retardant are mixed into flame-retardant TPU. The flame-retardant TPU obtained has good flame retardant properties, but poor wear resistance, poor transparency, or even opaque. When it is transparent, it is not resistant to hydrolysis, has poor flame retardant properties, poor heat aging resistance, and cannot achieve comprehensive good mechanical properties.

[0004] In order to improve the transparency and flame retardancy of TPU materials, solve the poor wear resistance, and enhance the thermal hydrolysis resistance and heat aging resistance, it is urgently necessary to provide a wear-resistant, flame-retardant, transparent polyurethane material and a preparation method thereof. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned defects in the prior art and provide a wear-resistant, flame-retardant, transparent polyurethane material and a preparation method thereof.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] A wear-resistant, flame-retardant, transparent polyurethane material, characterized in that the polyurethane material comprises the following components in parts by weight:

[0008] Polyurethane elastomer: 75-95.5 parts, dimethyl methylphosphonate: 2-15 parts, polycarbodiimide: 1-3 parts, quencher tris(2-chloroethyl)phosphate: 1-5 parts, curing chain extender: 0.3-2 parts.

[0009] A method for preparing a wear-resistant, flame-retardant, transparent polyurethane material, comprising:

[0010] S1. Add dimethyl methylphosphonate to polycarbodiimide, add tri(2-chloroethyl) phosphate as a quencher, disperse and mix evenly with a high-speed stirrer and ultrafine to obtain a hydrolysis-resistant and fast self-extinguishing dimethyl methylphosphonate flame retardant emulsion;

[0011] S2. The flame retardant emulsion of dimethyl methylphosphonate is placed in a reactor, a curing chain extender is added, and the mixture is heated and stirred uniformly to obtain modified dimethyl methylphosphonate;

[0012] S3. The modified dimethyl methylphosphonate is partially added to the polyurethane elastomer, and the curing chain extension reaction is performed and then cooled to room temperature to obtain a pre-cured tackified polyurethane elastomer; the remaining modified dimethyl methylphosphonate

[0013] The dimethyl ester is discharged for use;

[0014] S4. The pre-cured and tackified polyurethane elastomer is added to a twin-screw extruder from a first feed port, and the remaining modified dimethyl methylphosphonate is added to the twin-screw extruder from a second feed port through a liquid pump for blending and extrusion to obtain a wear-resistant, flame-retardant, transparent polyurethane material.

[0015] Implementing the embodiments of the present invention will have the following beneficial effects:

[0016] The embodiment of the present invention provides a wear-resistant flame-retardant transparent polyurethane material and a preparation method thereof. The wear-resistant flame-retardant transparent polyurethane material includes the following components in parts by weight: polyurethane elastomer (TPU): 75-95.5 parts, dimethyl methylphosphonate (DMMP): 2-15 parts, polycarbodiimide: 1-3 parts, quencher tris (2-chloroethyl) phosphate (TCEP): 1-5 parts, curing chain extender: 0.3-2 parts. DMMP is modified by adding polycarbodiimide to reduce the activity of phosphorus oxygen group and ester group, and the effect of promoting TPU degradation and hydrolysis when DMMP flame retardant is added to TPU is solved; by adding TCEP to hydrolysis-resistant DMMP, the burning flame can be quickly extinguished, so that it drips without flames; the synergistic effect of modified DMMP and curing chain extender performs solid chain extension on TPU, further improving the hydrolysis resistance and wear resistance of TPU. DMMP and TPU molecular chains not only form an interpenetrating network, but also have cross-linking and grafting, making the dispersion more uniform. A small amount of DMMP can make TPU highly flame retardant, and cross-linking and curing can extend the self-extinguishing time of TPU during the dripping process. The dripping droplets do not carry flames, are easy to extinguish during the dripping process, and are not easy to get cotton, thereby improving the flame retardant properties of TPU. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] in:

[0019] Figure 1 The present invention provides a flow chart of a method for preparing a wear-resistant, flame-retardant, transparent polyurethane material. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] The invention discloses a wear-resistant, flame-retardant, transparent polyurethane material, comprising the following components in parts by weight:

[0022] Polyurethane elastomer: 75-95.5 parts, dimethyl methylphosphonate: 2-15 parts, polycarbodiimide: 1-3 parts, quencher tris(2-chloroethyl)phosphate: 1-5 parts, curing chain extender: 0.3-2 parts.

[0023] Optionally, polyurethane elastomer: 95.5 parts, dimethyl methylphosphonate: 2 parts, polycarbodiimide: 1.2 parts, quencher tris(2-chloroethyl)phosphate: 1 part, curing chain extender: 0.3 parts.

[0024] Optionally, polyurethane elastomer: 92 parts, dimethyl methylphosphonate: 4 parts, polycarbodiimide: 1 part, quencher tris(2-chloroethyl)phosphate: 2.3 parts, curing chain extender: 0.7 parts.

[0025] Optionally, polyurethane elastomer: 85 parts, dimethyl methylphosphonate: 8 parts, polycarbodiimide: 2.2 parts, quencher tris(2-chloroethyl)phosphate: 3.5 parts, curing chain extender: 1.3 parts.

[0026] Optionally, 78 parts of polyurethane elastomer, 13 parts of dimethyl methylphosphonate, 2.8 parts of polycarbodiimide, 4.4 parts of quencher tris(2-chloroethyl)phosphate, and 1.8 parts of curing chain extender.

[0027] Optionally, polyurethane elastomer: 75 parts, dimethyl methylphosphonate: 15 parts, polycarbodiimide: 3 parts, quencher tris(2-chloroethyl)phosphate: 5 parts, curing chain extender: 2 parts.

[0028] Specifically, the curing chain extender includes 4,4-methylenebis(2,6-diethylaniline) (MDEA).

[0029] The polyurethane elastomer (TPU) can be polyester polyurethane particles and / or polyether polyurethane particles. The transparency of polyether TPU is relatively low but has good hydrolysis resistance. The hydrolysis resistance of polyester TPU is not as good as that of polyether TPU, but has higher transparency. Preferably, the polyurethane elastomer is polyester polyurethane particles, which have higher transparency.

[0030] Furthermore, by adding dimethyl methylphosphonate (DMMP), DMMP is first modified, and polycarbodiimide is added to reduce the activity of its phosphorus oxygen group and ester group, which greatly solves the effect of promoting TPU degradation and hydrolysis when DMMP fuel is added to TPU.

[0031] By adding tri(2-chloroethyl) phosphate (TCEP) with quenching and self-extinguishing effect to hydrolysis-resistant DMMP, the burning flame of TPU can be quickly extinguished, allowing it to drip without flame.

[0032] Through the synergistic effect of modified DMMP and curing chain extender MDEA, TPU is solid-state chain extended to further improve the hydrolysis resistance and wear resistance of TPU.

[0033] DMMP and TPU molecular chains not only form a blended interpenetrating network, but also have cross-linking and grafting, making the dispersion more uniform. A small amount of DMMP can make TPU highly flame retardant, and cross-linking and curing can extend the self-extinguishing time of TPU during the dripping process. The dripping droplets do not carry flames, are easy to extinguish during the dripping process, and are not easy to get cotton, thereby improving the flame retardant properties of TPU.

[0034] It is understandable that the present embodiment discloses a wear-resistant flame-retardant transparent polyurethane material, comprising the following components in parts by weight: polyurethane elastomer: 75-95.5 parts, dimethyl methylphosphonate: 2-15 parts, polycarbodiimide: 1-3 parts, quencher tris(2-chloroethyl)phosphate: 1-5 parts, curing chain extender: 0.3-2 parts. The addition of DMMP flame retardant improves the flame retardancy of TPU. By adding polycarbodiimide to modify DMMP, the activity of its phosphorus oxygen group and ester group is reduced, and the effect of promoting the degradation and hydrolysis of TPU when DMMP flame retardant is added to TPU is solved; by adding TCEP to the hydrolysis-resistant DMMP, the burning flame of TPU can be quickly extinguished, so that it drips without flames; the synergistic effect of the modified DMMP and the curing chain extender performs solid chain extension on TPU, further improving the hydrolysis resistance and wear resistance of TPU.

[0035] In some optional embodiments, the wear-resistant flame-retardant transparent polyurethane material includes the following components in parts by weight: polyurethane elastomer: 80-90 parts, dimethyl methylphosphonate: 5-12 parts, polycarbodiimide: 1.5-2.5 parts, quencher tri(2-chloroethyl) phosphate: 2-4 parts, and curing chain extender: 0.8-1.5 parts.

[0036] Optionally, polyurethane elastomer: 90 parts, dimethyl methylphosphonate: 5 parts, polycarbodiimide: 2.2 parts, quencher tris(2-chloroethyl)phosphate: 2 parts, curing chain extender: 0.8 parts.

[0037] Optionally, polyurethane elastomer: 87.5 parts, dimethyl methylphosphonate: 7 parts, polycarbodiimide: 2.5 parts, quencher tris(2-chloroethyl)phosphate: 2.1 parts, curing chain extender: 0.9 parts.

[0038] Optionally, polyurethane elastomer: 85 parts, dimethyl methylphosphonate: 9 parts, polycarbodiimide: 1.5 parts, quencher tris(2-chloroethyl)phosphate: 3.5 parts, curing chain extender: 1.0 part.

[0039] Optionally, polyurethane elastomer: 82.5 parts, dimethyl methylphosphonate: 10 parts, polycarbodiimide: 2.3 parts, quencher tris(2-chloroethyl)phosphate: 3.9 parts, curing chain extender: 1.3 parts.

[0040] Optionally, polyurethane elastomer: 80 parts, dimethyl methylphosphonate: 12 parts, polycarbodiimide: 2.5 parts, quencher tris(2-chloroethyl)phosphate: 4 parts, curing chain extender: 1.5 parts.

[0041] The effect of the wear-resistant, flame-retardant, transparent polyurethane material in this embodiment is the same as that in the above embodiment, and will not be described in detail here.

[0042] In some optional embodiments, the wear-resistant flame-retardant transparent polyurethane material includes the following components in parts by weight: polyurethane elastomer: 85 parts, dimethyl methylphosphonate: 8 parts, polycarbodiimide: 2 parts, quencher tri(2-chloroethyl) phosphate: 2.7 parts, and curing chain extender: 1.2 parts.

[0043] The effect of the wear-resistant, flame-retardant, transparent polyurethane material in this embodiment is the same as that in the above embodiment, and will not be described in detail here.

[0044] Reference Figure 1 The present invention discloses a method for preparing a wear-resistant, flame-retardant, transparent polyurethane material, comprising:

[0045] S1. Add dimethyl methylphosphonate to polycarbodiimide, add tri(2-chloroethyl) phosphate as a quencher, disperse and mix evenly with a high-speed stirrer and ultrafine to obtain a hydrolysis-resistant and fast self-extinguishing dimethyl methylphosphonate flame retardant emulsion;

[0046] S2. The flame retardant emulsion of dimethyl methylphosphonate is placed in a reactor, a curing chain extender is added, and the mixture is heated and stirred uniformly to obtain a modified dimethyl methylphosphonate;

[0047] S3. The modified dimethyl methylphosphonate is partially added to the polyurethane elastomer, and the curing chain extension reaction is carried out and then cooled to room temperature to obtain a pre-cured tackified polyurethane elastomer; the remaining modified dimethyl methylphosphonate is discharged for standby use;

[0048] S4. The pre-cured and tackified polyurethane elastomer is added to the twin-screw extruder from the first feed port, and the remaining modified dimethyl methylphosphonate is added to the twin-screw extruder from the second feed port through a liquid pump for blending and extrusion to obtain a wear-resistant, flame-retardant, transparent polyurethane material.

[0049] Specifically, S1. 2-15 parts of DMMP are added to 1-3 parts of polycarbodiimide, so that the polycarbodiimide is plasticized and thinned with high viscosity, and the ester group in DMMP is anchored to prevent DMMP from decomposing into free radicals and causing degradation in TPU. TCEP is added at the same time, dispersed and homogenized by a high-speed stirrer, and then ultra-finely processed to obtain a hydrolysis-resistant and fast self-extinguishing dimethyl methylphosphonate flame retardant emulsion.

[0050] S2. Place the prepared hydrolysis-resistant and fast self-extinguishing dimethyl methylphosphonate flame-retardant emulsion in a reactor, add 0.3-2 parts of curing chain extender MDEA, and stir for 5 min-10 min; heat to 90°C-100°C and react for 10 min-15 min, and stir evenly while heating to obtain modified dimethyl methylphosphonate.

[0051] S3. Add 1 / 3-1 / 2 of the modified dimethyl methylphosphonate to TPU that has been baked at 100°C for 3 hours, stir for 10min-12min, react at 60°C-80°C for 30min-120min under N2 protection to carry out curing and chain extension reaction, and finally cool to room temperature to obtain a pre-cured and tackified polyurethane elastomer, which is discharged for use; the remaining 1 / 2-2 / 3 of the modified dimethyl methylphosphonate is also discharged for use.

[0052] S4. The pre-cured and tackified TPU is added to the twin-screw extruder from the first feed port for dynamic crosslinking and flame retardancy, and the remaining 1 / 2-2 / 3 of the modified dimethyl methylphosphonate is added to the twin-screw extruder through a liquid pump for blending and extrusion.

[0053] Specifically, the processing temperature of the twin-screw extruder is controlled at 165-190°C, and the specific extrusion process parameters are: first section 25-40°C, second section 155°C, third section 165°C, fourth section 175°C, fifth section 175°C, sixth section 180°C, seventh section 185°C, eighth section 185°C, ninth section 185°C, die head 190°C, main engine rotation speed: 250rpm-350rpm, feeding speed 30rpm.

[0054] It can be understood that, through the preparation method of the wear-resistant flame-retardant transparent polyurethane material in this embodiment, the polycarbodiimide is first plasticized and diluted with the DMMP flame retardant, and the polycarbodiimide is used to capture the water in the DMMP and react with the phosphorus group and ester group in the DMMP to ensure flame retardancy while reducing the activity of the phosphorus group, which greatly prevents the catalytic degradation and hydrolysis of the TPU by the phosphate flame retardant. The addition of the curing chain extender MDEA is melt-mixed with the DMMP at a high temperature to promote the further chain extension, cross-linking and curing stability of the DMMP. Compared with the unmodified DMMP, it not only reduces the catalytic degradation effect of the ester flame retardant on the polyurethane, but also acts as an absorbent of the carboxyl group of the TPU to prevent the hydrolysis of the TPU. Under the synergistic effect of the modified DMMP and the curing chain extender, the TPU is cross-linked, the wear resistance is improved, and the hydrolysis and degradation of the ester group of the TPU is reduced.

[0055] Embodiment 1:

[0056] The wear-resistant flame-retardant transparent polyurethane material comprises the following components in parts by weight: 95.5 parts of polyurethane elastomer, 2 parts of dimethyl methylphosphonate, 1 part of polycarbodiimide, 1 part of quencher tris(2-chloroethyl)phosphate, and 0.3 parts of curing chain extender.

[0057] Embodiment 2:

[0058] The wear-resistant flame-retardant transparent polyurethane material comprises the following components in parts by weight: 85 parts of polyurethane elastomer, 8 parts of dimethyl methylphosphonate, 2.2 parts of polycarbodiimide, 3.5 parts of quencher tris(2-chloroethyl)phosphate, and 1.3 parts of curing chain extender.

[0059] Embodiment 3:

[0060] The wear-resistant flame-retardant transparent polyurethane material comprises the following components in parts by weight: 75 parts of polyurethane elastomer, 15 parts of dimethyl methylphosphonate, 3 parts of polycarbodiimide, 5 parts of quencher tris(2-chloroethyl)phosphate, and 2 parts of curing chain extender.

[0061] Comparative Example 1:

[0062] Compared with Example 1, no chain extender was added.

[0063] Comparative Example 2:

[0064] Compared to Example 1, no polycarbodiimide was added.

[0065] Comparative Example 3:

[0066] Compared to Example 1, no quencher tris(2-chloroethyl) was added.

[0067] Experimental example

[0068] The pellets prepared in the embodiments and comparative examples of the present invention were taken for sample preparation. The specific sample preparation method was as follows: the pellets of all embodiments and comparative examples were dried and directly added to the pipe production line to directly extrude a transparent TPU tube with a diameter of 8MM. The vertical flame retardant performance of the product was tested according to GB / T2408. The transparent TPU tube produced was tested for wear resistance according to ISO6722, and the number of wear resistance failures was recorded. The double 85 heat resistance and hydrolysis resistance test was to place the sample in a constant temperature and humidity chamber at a temperature of 85 degrees and a humidity of 85% for 240 hours. Then, the treated TPU transparent tube was repeatedly bent 10 times to observe whether it was hardened, cracked, broken, changed in transparency, or discolored. The results are shown in Table 1.

[0069] Table 1 Formulation and performance comparison

[0070]

[0071] It can be concluded from Table 1 that the flame retardant properties, wear resistance, and transparency of the products after double 85 heat and humidity resistance of Examples 1-3 are all optimal, while the flame retardant properties of the comparative examples obviously cannot reach V0, and the wear resistance times are also reduced. Among them, the comparative example 1 without curing chain extension and the comparative example 2 without polycarbodiimide both show discoloration and opacity after the heat and humidity hydrolysis test, and the wear resistance times are also reduced, indicating that the curing chain extender, polycarbodiimide and quencher tri(2-chloroethyl) phosphate have synergistic flame retardancy, while improving the wear resistance and heat and humidity hydrolysis resistance. The mutual synergistic effect of the three additives solves the problem of flame retardant dripping and cottoning, solves the problem of deterioration of wear resistance after adding flame retardants, and also solves the problem of TPU's poor hydrolysis resistance, especially the sharp deterioration of transparency and color after adding flame retardants.

[0072] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A wear-resistant, flame-retardant, transparent polyurethane material, characterized in that: The polyurethane material comprises the following components in parts by weight: Polyurethane elastomer: 75-95.5 parts, dimethyl methylphosphonate: 2-15 parts, polycarbodiimide: 1-3 parts, quencher tris(2-chloroethyl)phosphate: 1-5 parts, curing chain extender: 0.3-2 parts.

2. The wear-resistant, flame-retardant, transparent polyurethane material according to claim 1, characterized in that: The polyurethane material comprises the following components in parts by weight: The polyurethane elastomer is 80-90 parts, the dimethyl methylphosphonate is 5-12 parts, the polycarbodiimide is 1.5-2.5 parts, the quencher tris(2-chloroethyl)phosphate is 2-4 parts, and the curing chain extender is 0.8-1.5 parts.

3. The wear-resistant, flame-retardant, transparent polyurethane material according to claim 1, characterized in that: The polyurethane material comprises the following components in parts by weight: The polyurethane elastomer: 85 parts, the dimethyl methylphosphonate: 8 parts, the polycarbodiimide: 2 parts, the quencher tris(2-chloroethyl)phosphate: 2.7 parts, and the curing chain extender: 1.2 parts.

4. The wear-resistant, flame-retardant, transparent polyurethane material according to claim 1, characterized in that: The curing chain extender includes 4,4-methylenebis(2,6-diethylaniline).

5. The wear-resistant, flame-retardant, transparent polyurethane material according to claim 1, characterized in that: The polyurethane elastomer is polyester polyurethane particles.

6. A method for preparing a wear-resistant, flame-retardant, transparent polyurethane material, characterized in that: include: S1. Add dimethyl methylphosphonate to polycarbodiimide, add tri(2-chloroethyl) phosphate as a quencher, disperse and mix evenly with a high-speed stirrer and ultrafine to obtain a hydrolysis-resistant and fast self-extinguishing dimethyl methylphosphonate flame retardant emulsion; S2. The flame retardant emulsion of dimethyl methylphosphonate is placed in a reactor, a curing chain extender is added, and the mixture is heated and stirred uniformly to obtain modified dimethyl methylphosphonate; S3. The modified dimethyl methylphosphonate is partially added to the polyurethane elastomer, and the curing chain extension reaction is performed and then cooled to room temperature to obtain a pre-cured tackified polyurethane elastomer; the remaining modified dimethyl methylphosphonate is discharged for standby use; S4. The pre-cured and tackified polyurethane elastomer is added to a twin-screw extruder from a first feed port, and the remaining modified dimethyl methylphosphonate is added to the twin-screw extruder from a second feed port through a liquid pump for blending and extrusion to obtain a wear-resistant, flame-retardant, transparent polyurethane material.

7. The method for preparing the wear-resistant, flame-retardant, transparent polyurethane material according to claim 6, characterized in that: The processing temperature of the twin-screw extruder is controlled at 165°C-190°C.

8. The method for preparing the wear-resistant, flame-retardant, transparent polyurethane material according to claim 6, characterized in that: The extrusion process parameters of the twin-screw extruder are: 25°C-40°C in the first section, 155°C in the second section, 165°C in the third section, 175°C in the fourth section, 175°C in the fifth section, 180°C in the sixth section, 185°C in the seventh section, 185°C in the eighth section, 185°C in the ninth section, and 190°C in the die.

9. The method for preparing the wear-resistant, flame-retardant, transparent polyurethane material according to claim 6, characterized in that: The main engine speed of the twin-screw extruder is 250rpm-350rpm, and the feeding speed is 30rpm.

10. The method for preparing the wear-resistant, flame-retardant, transparent polyurethane material according to claim 6, characterized in that: The curing chain extender includes 4,4-methylenebis(2,6-diethylaniline).

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