A thermoplastic polyurethane composite and its preparation method and application

Abstract

The invention discloses a thermoplastic polyurethane composite and a preparation method and application thereof. The thermoplastic polyurethane composite comprises the following components by weight: 40 to 60 parts of polyether thermoplastic polyurethane; 40 to 60 parts of polycaprolactone thermoplastic polyurethane; 1 to 3 parts of silicone lubricant; 0.5 to 1.5 parts of amide lubricant; 0.5 to 3 parts of ester lubricant; 0.05 to 2 parts of titanium dioxide; 0 to 3 parts of other functional additives. The thermoplastic polyurethane composite of the invention can maintain good elasticity and low demoulding force in a wide temperature range (-40°C to 60°C), can be processed and formed by injection molding and other processes, and is suitable for producing large aspect ratio parts such as soft toothbrush bristles.

Description

Technical Field

[0001] The present invention relates to the technical field of polyurethane, and more specifically to a thermoplastic polyurethane composite and a preparation method and application thereof. Background Art

[0002] Thermoplastic polyurethane materials have excellent elasticity, chemical solvent resistance, fatigue resistance, etc., and have been increasingly used in sporting goods, office chairs, mobile phone cases, automotive wiring harnesses and other fields.

[0003] Thermoplastic polyurethane has excellent elasticity and is an ideal material for producing soft toothbrush bristles. Thermoplastic polyurethane currently used for toothbrush bristles is usually polyester polyurethane or polyether polyurethane. At room temperature, thermoplastic polyurethane has excellent resilience and moderate elasticity, and can clean teeth efficiently, but toothbrush bristles made from polyester thermoplastic polyurethane will become very hard and lose elasticity at low temperatures. In cold environments, when used outdoors, it cannot clean teeth efficiently and is easy to damage the gums. The bristles made from polyether polyurethane tend to become softer and less elastic at high temperatures. Some consumers like to soak their toothbrushes in warm water before using them. At this time, the cleaning ability of the bristles becomes very poor, affecting the user experience.

[0004] In addition, thermoplastic polyurethane material is a highly polar material with a slow cooling rate, and has a relatively large interaction force with the mold. When used to prepare parts with a large aspect ratio, there is a problem of large demolding force, which may damage the parts. Summary of the invention

[0005] The primary purpose of the present invention is to overcome the problems of large elasticity changes and large demoulding force of existing thermoplastic polyurethanes at high and low temperatures, and to provide a thermoplastic polyurethane composite. The thermoplastic polyurethane composite of the present invention can maintain good elasticity in a wide temperature range (-40°C to 60°C).

[0006] Another object of the present invention is to provide a method for preparing a thermoplastic polyurethane composite.

[0007] Another object of the present invention is to provide application of the thermoplastic polyurethane compound.

[0008] The above-mentioned object of the present invention is achieved by the following technical solutions:

[0009] A thermoplastic polyurethane composite comprises the following components in parts by weight:

[0010]

[0011]

[0012] The present invention is compounded by mixing specific amounts of polyether thermoplastic polyurethane and polycaprolactone thermoplastic polyurethane, and adding silicone lubricants, amide lubricants, and ester lubricants. The terminal amino group and terminal hydroxyl group in the lubricant interact with the carbamate group in the polyurethane molecule to weaken the intramolecular hydrogen bond density of the polyether polyurethane and the polycaprolactone polyurethane, so that the two form a uniform network structure, and their molecular chains are entangled with each other in the amorphous phase region. At low temperatures, the soft segment of the polyether thermoplastic polyurethane can play a certain plasticizing role on the polycaprolactone polyurethane to prevent its crystallization and hardening; at high temperatures, the polycaprolactone polyurethane molecules have a certain rigidity, which can constrain the movement of the polyether polyurethane molecular chain to prevent it from softening and losing elasticity at high temperatures, thereby overcoming the problem of large elastic changes of thermoplastic polyurethane at high and low temperatures. The addition of the lubricant also plays a role in reducing the demoulding force.

[0013] Preferably, the thermoplastic polyurethane composite comprises the following components in parts by weight:

[0014]

[0015] Preferably, the glass transition temperature of the polyether thermoplastic polyurethane measured according to the test standard ISO 11357:2016 is ≤-30°C; the glass transition temperature of the polycaprolactone thermoplastic polyurethane measured according to the test standard ISO 11357:2016 is ≥-20°C.

[0016] Conventional silicone lubricants in the art can be used in the present invention. Generally, the silicone lubricant is selected from silicone and / or silicone masterbatch.

[0017] Conventional amide lubricants in the art can be used in the present invention. Generally, the amide lubricant is selected from one or more of erucamide, oleamide, and EBS (stearic acid amide).

[0018] Conventional ester lubricants in the art can be used in the present invention. Generally, the ester lubricant is selected from one or both of pentaerythritol stearate and pentaerythritol esters with a saponification value of 187 to 201 mgKOH / g.

[0019] Preferably, the titanium dioxide is rutile titanium dioxide, which can induce the thermoplastic polyester elastomer to form a crystalline structure faster during the cooling process.

[0020] In order to obtain more excellent or new performance, the thermoplastic polyurethane composite of the present invention may further include other functional additives conventional in the art, and the type and amount of each functional additive may be selected and adjusted according to actual needs.

[0021] Preferably, the other functional auxiliary agents are selected from one or more of antioxidants and UV resistant agents.

[0022] The antioxidant is selected from one or more of hindered phenol antioxidants, phosphite antioxidants, aniline antioxidants, and thioester antioxidants.

[0023] The anti-UV agent is selected from one or more of benzophenone anti-UV agents, benzotriazole anti-UV agents, and hindered amine anti-UV agents.

[0024] The present invention also provides a method for preparing a thermoplastic polyurethane composite, comprising the following steps:

[0025] Polyether thermoplastic polyurethane, polycaprolactone thermoplastic polyurethane, silicone lubricant, amide lubricant, ester lubricant, titanium dioxide and other functional additives are mixed, extruded and granulated through a twin-screw extruder to obtain a thermoplastic polyurethane composite.

[0026] Preferably, the extrusion temperature is 160-230°C.

[0027] Preferably, the length-to-diameter ratio of the twin-screw extruder used is 36 to 60 / 1, and the residence time of the mixed material in the screw is 40 to 90 seconds.

[0028] The thermoplastic polyurethane composite of the present invention can maintain good elasticity and low demoulding force in a wide temperature range (-40°C to 60°C), and can be used to prepare large aspect ratio parts, such as soft toothbrush bristles, etc. Therefore, the application of the thermoplastic polyurethane composite in the preparation of large aspect ratio parts should also be within the protection scope of the present invention.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The invention provides a thermoplastic polyurethane composite. By compounding specific amounts of polyether thermoplastic polyurethane, polycaprolactone thermoplastic polyurethane and appropriate lubricant, the prepared thermoplastic polyurethane composite can maintain good elasticity within a wide temperature range (-40°C to 60°C), and the demoulding force does not exceed 3800N. The composite can be processed and formed by injection molding and other processes, and is particularly suitable for the preparation of parts with a large aspect ratio, such as soft toothbrush bristles. DETAILED DESCRIPTION

[0031] In order to more clearly and completely describe the technical solution of the present invention, the present invention is further described in detail through specific embodiments below. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention. Various changes can be made within the scope of the rights of the present invention.

[0032] The present invention will be further described below in conjunction with specific implementation modes.

[0033] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the present technical field.

[0034] The raw materials in the embodiments and comparative examples can be obtained from commercial sources, as follows:

[0035]

[0036]

[0037] The thermoplastic polyurethane composites described in the examples and comparative examples were prepared by the following method:

[0038] Polyether thermoplastic polyurethane, polycaprolactone thermoplastic polyurethane, silicone lubricant, amide lubricant, ester lubricant, titanium dioxide and other functional additives are put into a high-speed mixer and mixed evenly, and then fed into a twin-screw extruder by loss-in-weight metering. After extrusion at 160-230°C, the thermoplastic polyurethane composite is obtained after granulation and drying.

[0039] The length-to-diameter ratio of the twin-screw extruder used is 36-60 / 1, and the residence time of the mixed material in the screw is 40-90 seconds.

[0040] Examples 1 to 9

[0041] Examples 1 to 9 provide a thermoplastic polyurethane composite, and the amount of each raw material used is shown in Table 1.

[0042] Table 1 Amount of each raw material used in Examples 1 to 9 (parts by weight)

[0043]

[0044] Embodiments 10 to 25

[0045] Examples 10 to 25 provide a series of thermoplastic polyurethane composites, and the amount of each raw material used is shown in Table 2.

[0046] Table 2 Amount of each raw material used in Examples 10 to 25 (parts by weight)

[0047]

[0048]

[0049] Comparative Examples 1 to 9

[0050] Comparative Examples 1 to 9 provide a series of thermoplastic polyurethane composites, and the amount of each raw material used is shown in Table 3.

[0051] Table 3 Amount of each raw material used in Comparative Examples 1 to 9 (parts by weight)

[0052]

[0053]

[0054] Performance Testing

[0055] The thermoplastic polyurethane composites prepared in the above examples and comparative examples were subjected to performance tests.

[0056] Elasticity test method:

[0057] The thermoplastic polyurethane compound was injection molded into a rectangular plate of 15mm*25mm and 3mm thick. Cylinders with a diameter of 0.5mm and a length of 10mm were distributed on the rectangular plate, and the small cylinders were distributed in 10*20. The rectangular plate was fixed on the fixture. At 1 / 2 of the height of the cylinder, a 20mm*80mm metal plate was moved perpendicular to the cylinder at a speed of 20mm / min, crossing all the cylinders, and the elastic force received by the metal sheet was recorded by the pressure sensor. The whole set of fixtures was placed in -40℃ and 60℃ environmental boxes, and the elastic forces f1 and f2 of the thermoplastic polyurethane elastomer at -40℃ and 60℃ were recorded respectively. The elastic force change value △f=f1-f2.

[0058] Demolding force test method:

[0059] Thermoplastic polyurethane is injection molded into a cylindrical part, where the outer diameter of the cylinder is 50mm, the wall thickness is 2mm, and the height of the cylinder is 60mm. Two pressure sensors are installed behind the ejection device of the demoulding to measure the demoulding force during the demoulding process. The sum of the pressures measured by the two pressure sensors is used to evaluate the demoulding force (unit: N).

[0060] The test results of Examples 1 to 25 are shown in Table 4.

[0061] Table 4 Test results of the thermoplastic polyurethane composites described in Examples 1 to 25.

[0062]

[0063]

[0064] Table 4

[0065] Example 13 14 15 16 17 18 19 20 21 22 23 24 25 f1(-40℃) 6.9 7.4 7.1 7.3 7 6.9 7.2 6.9 7 7.1 7.1 7.0 7.9 f2(60℃) 4.4 4.7 4.5 4.6 4.3 4.4 4.5 4.3 4.5 4.6 4.7 4.1 4.3 △f 2.5 2.7 2.6 2.7 2.7 2.5 2.7 2.6 2.5 2.5 2.4 2.9 3.6 Release force 3610 3580 3530 3525 3605 3590 3780 3610 3600 3530 3520 3530 3770

[0066] The test results of Comparative Examples 1 to 9 are shown in Table 5 below.

[0067] Table 5 shows the test results of the thermoplastic polyurethane composites described in Comparative Examples 1 to 9.

[0068] Comparative Example 1 2 3 4 5 6 7 8 9 f1(-40℃) 6.9 19.3 10.8 10.6 10.3 10.2 10.2 10.4 7.5 f2(60℃) 1.2 4.9 2.1 2.3 3.6 3.5 3.4 3.7 0.6 △f 5.7 14.4 8.7 8.3 6.7 6.7 6.8 6.7 6.9 Release force 3670 3320 4130 4350 5320 5160 5460 5380 3750

[0069] It can be seen from Table 4 that the thermoplastic polyurethane composites described in Examples 1 to 25 can maintain good elasticity within the range of -40°C to 60°C, the elastic force at -40°C is less than 10N, the elastic force at 60°C is not less than 2N, the elasticity change value △f is less than 5N, and the demolding force does not exceed 3800N. They can be processed and formed by injection molding and other processes, and are suitable for producing large aspect ratio parts such as soft toothbrush bristles.

[0070] As shown in Table 5, when polyether polyurethane or polycaprolactone thermoplastic polyurethane is used alone, or the ratio of polyether thermoplastic polyurethane to polycaprolactone thermoplastic polyurethane is not within the range, the elastic force at -40°C is very different from the elastic force at 60°C, and the elastic change value △f is also large, and the soft toothbrush bristles produced have a poor user experience. When a lubricant is missing, the demoulding force is greater than 5000N, and it is difficult to demould when producing toothbrush bristle parts with a large aspect ratio, and normal production cannot be achieved.

[0071] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A thermoplastic polyurethane composite, characterized in that: The composition comprises the following components by weight: The silicone lubricant is selected from silicone and / or silicone masterbatch; The amide lubricant is selected from one or more of erucamide, oleamide, and EBS; The ester lubricant is selected from one or both of pentaerythritol stearate and pentaerythritol ester with a saponification value of 187-201 mgKOH / g.

2. The thermoplastic polyurethane composite according to claim 1, characterized in that: The composition comprises the following components by weight:

3. The thermoplastic polyurethane composite according to claim 1, characterized in that: The glass transition temperature of the polyether thermoplastic polyurethane measured according to the test standard ISO 11357:2016 is ≤-30°C; the glass transition temperature of the polycaprolactone thermoplastic polyurethane measured according to the test standard ISO 11357:2016 is ≥-20°C.

4. The thermoplastic polyurethane composite according to claim 1, characterized in that: The titanium dioxide is rutile titanium dioxide.

5. The thermoplastic polyurethane composite according to claim 1, characterized in that: The other functional additives are selected from one or more of antioxidants and UV resistant agents.

6. The method for preparing the thermoplastic polyurethane composite according to any one of claims 1 to 5, characterized in that: The steps include: The polyether type thermoplastic polyurethane, polycaprolactone type thermoplastic polyurethane, silicone lubricant, amide lubricant, ester lubricant, titanium dioxide and other functional additives are mixed, extruded and granulated to obtain a thermoplastic polyurethane composite.

7. Use of the thermoplastic polyurethane composite according to any one of claims 1 to 5 in the preparation of products with a large aspect ratio.

Images