Polyurethane engineering plastic with scratch-resistant body

Abstract

The invention belongs to the field of thermoplastic polyurethane resin, and provides a body scratch-resistant polyurethane engineering plastic, which is prepared by polymerizing the following raw materials in percentage by weight: 45 to 68 weight percent of rigid diisocyanate, 32 to 55 weight percent of micromolecular dihydric alcohol and 10 to 2000 ppm of catalyst. Through the structural design of the polymer, a large number of high-rigidity groups are introduced into a main chain, and the problem of low surface hardness of the material is fundamentally solved on the premise that the structural characteristics of polyurethane are reserved. The product obtained by the invention has high permeability, high strength and high toughness of polyurethane engineering plastic, also has high surface hardness, and can meet the requirements of various easily worn and scraped outer parts.

Description

Technical Field

[0001] The invention belongs to the field of thermoplastic polyurethane resins, and in particular relates to a polyurethane engineering plastic with a scratch-resistant body and a preparation method thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] The polymer materials commonly used to make hard shells, such as ABS, polycarbonate, copolyester, nylon, etc., will leave marks on the surface due to friction and scratches during daily use. The marks left cannot be eliminated and have a great impact on the appearance of the product. Although polymethyl methacrylate has a high surface hardness, it has extremely poor toughness, is notch-sensitive, and is prone to stress cracking. It cannot be used in areas where drop and impact resistance are required.

[0004] In order to solve the problem that the surface of polymer materials is prone to scratches during use, two main measures are taken. One is to use surface treatment methods to improve the surface hardness of the shell; the other is to use body modification methods to directly improve the surface hardness of the material body. Surface treatment methods increase the complexity of processing and increase production costs, and the surface treatment agent will gradually fall off during use, causing the surface hardness to drop again. Directly improving the surface hardness of the material body is currently generally carried out by blending modification. Although the addition of modifiers such as polymethyl methacrylate will improve the surface hardness, it will also significantly reduce the toughness of the material. In summary, it is difficult for existing methods to simultaneously meet the performance requirements of permanent transparency, high toughness and high surface hardness. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a polyurethane engineering plastic with a scratch-resistant body and a preparation method thereof.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] The first aspect of the present invention provides a polyurethane engineering plastic with a body that is scratch-resistant, which is polymerized from the following raw materials in percentage by weight: 45wt% to 68wt% of rigid diisocyanate, 32wt% to 55wt% of small molecule diol, and 10 to 2000ppm of catalyst, the sum of the percentages of each raw material being 100%;

[0008] Among them, the rigid diisocyanate has two characteristics:

[0009] (1) Both isocyanate groups are directly attached to the aliphatic or aromatic ring;

[0010] (2) There is no flexible group connecting the alicyclic ring and the aromatic ring in the molecule, and the flexible group includes: methylene and ether bond;

[0011] The small molecule diol contains an ester ring.

[0012] In some embodiments, the rigid diisocyanate is selected from at least one of p-phenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,4-cyclohexane diisocyanate, and 3,3′-dimethyl-4,4′-biphenyl diisocyanate.

[0013] Small molecule diols all contain alicyclic rings with strong rigidity, and are combined with high rigidity diisocyanates. The two together enhance the rigidity of the main chain, so that the polymer has the characteristics of high modulus and high surface hardness. At the same time, the alicyclic structure of the selected small molecule diols deteriorates the regularity of the main chain, effectively inhibits the crystallization of the polyurethane chain segments, and makes the product highly transparent. Therefore, in some embodiments, the small molecule diol is selected from at least one of isosorbide, tricyclo[5.2.1,2,6]decanedimethanol, 1,4-cyclohexanedimethanol, and 2,2,4,4-tetramethyl-1,3-cyclobutanediol.

[0014] Although isocyanate and hydroxyl generally show high activity and can react spontaneously. However, it is found in actual experiments that the steric effect of alicyclic diols greatly reduces the reactivity of hydroxyl groups. If no catalyst is added, the polymerization degree of the reaction will be seriously affected, thereby further affecting the product performance. Adding a catalyst can effectively shorten the viscosity increase rate of the system and increase the molecular weight of the product. Therefore, in some embodiments, the catalyst is an organotin or organobismuth esterification catalyst.

[0015] In some embodiments, the catalyst is stannous octoate or bismuth neodecanoate.

[0016] The increased rigidity of the main chain can increase the glass transition temperature (Tg) of the material, thereby improving the processing performance of the material. Too high a processing temperature can accelerate the degradation of polyurethane during processing, thereby affecting the appearance and performance of the product. Taking this into account, the present invention does not use a fully aromatic main chain (i.e., aromatic diisocyanate and aromatic small molecule diol polymerization) as one of the optional solutions. At the same time, in some embodiments, a linear small molecule diol is used to partially replace the small molecule diol containing an ester ring, so as to obtain a lower processing temperature at the expense of a little surface hardness.

[0017] The second aspect of the present invention provides a method for preparing a polyurethane engineering plastic having a body that is scratch-resistant, comprising:

[0018] Heat the small molecule diol to 80-150°C, add rigid diisocyanate and catalyst, stir until viscous, then stop stirring, and mature at 90-120°C to obtain the product.

[0019] In some embodiments, the stirring speed is 500-1500 r / min.

[0020] In some embodiments, the aging time is 12 hours to 24 hours.

[0021] The third aspect of the present invention provides the use of the above-mentioned scratch-resistant polyurethane engineering plastic in the fields of construction, automobiles, aviation industry, thermal insulation, and mechanical parts.

[0022] Beneficial effects of the present invention

[0023] (1) The scratch resistance of a material is related to the ability of the material surface to resist deformation or damage. Generally speaking, the stronger the rigidity of the main chain of the material, the higher its strength and the harder the surface. However, high main chain rigidity generally means poor material toughness and high processing difficulty. The use of traditional materials cannot simultaneously meet the requirements of transparency, high toughness and high surface hardness. The scratch-resistant polyurethane engineering plastic provided by the present invention introduces a large number of high-rigidity groups into the main chain through polymer structure design, which fundamentally solves the problem of low surface hardness of the material while retaining the structural characteristics of the polyurethane. The product obtained by the present invention has the high permeability, high strength and high toughness of polyurethane engineering plastics, and at the same time, it also has a higher surface hardness, which can meet the needs of various appearance parts that are prone to wear and scratching.

[0024] (2) The preparation method of the present invention is simple, practical and easy to promote. DETAILED DESCRIPTION

[0025] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0026] The present invention will be further described in detail below in conjunction with specific embodiments. It should be noted that the specific embodiments are intended to explain the present invention rather than to limit it.

[0027] Example 1

[0028] Heat 146.14g of isosorbide to 80°C and pour it into a reaction container. Under stirring at 1500r / min, quickly add 169.50g of 1,4-cyclohexane diisocyanate to the reaction container, and simultaneously add 0.63g of bismuth neodecanoate as a catalyst. Stir until it becomes viscous, then stop stirring, place the polymer together with the reaction container in a 90°C oven for aging for 24h to obtain a high-hardness polyurethane engineering plastic.

[0029] Example 2

[0030] Heat 196.28g of tricyclo[5.2.1,2,6]decane dimethanol to 150°C and pour into a reaction vessel. Under stirring at 500r / min, quickly add 214.39g of p-phenylene diisocyanate into the reaction vessel, and simultaneously add 0.36g of stannous octoate as a catalyst. Stir until viscous, then stop stirring, place the polymer together with the reaction vessel in a 120°C oven for aging for 12h to obtain a high-hardness polyurethane engineering plastic.

[0031] Example 3

[0032] Heat 144.21 g of 1,4-cyclohexanedimethanol to 100°C and pour it into a reaction container. Under stirring at 1000 r / min, quickly add 169.50 g of 1,5-naphthalene diisocyanate into the reaction container, and simultaneously add 0.0035 g of stannous octoate as a catalyst. Stir until it becomes viscous, then stop stirring, place the polymer together with the reaction container in a 100°C oven for aging for 16 hours, and obtain a high-hardness polyurethane engineering plastic.

[0033] Example 4

[0034] Heat 144.21 g of 2,2,4,4-tetramethyl-1,3-cyclobutanediol to 100°C and pour it into a reaction container. Under stirring at 1000 r / min, quickly add 272.21 g of 3,3'-dimethyl-4,4'-biphenyl diisocyanate into the reaction container, and simultaneously add 0.008 g of stannous octoate as a catalyst. Stir until it becomes viscous, then stop stirring, place the polymer together with the reaction container in a 100°C oven for aging for 16 hours, and obtain a high-hardness polyurethane engineering plastic.

[0035] Example 5

[0036] Heat 146.14g of isosorbide to 100°C and pour it into a reaction container. Under stirring at 1000r / min, quickly add 161.73g of p-phenylene diisocyanate into the reaction container, and simultaneously add 0.03g of stannous octoate as a catalyst. Stir until it becomes viscous, then stop stirring, place the polymer together with the reaction container in a 100°C oven for aging for 16 hours, and obtain a high-hardness polyurethane engineering plastic.

[0037] Example 6

[0038] Heat 86.53g of 1,4-cyclohexanedimethanol and 57.68g of 2,2,4,4-tetramethyl-1,3-cyclobutanediol to 100°C and pour them into a reaction container. Under stirring at 1000r / min, quickly add 214.39g of 1,5-naphthalene diisocyanate to the reaction container, and add 0.06g of bismuth neodecanoate as a catalyst. Stir until it becomes viscous, then stop stirring, place the polymer and the reaction container in a 100°C oven for aging for 16h to obtain a high-hardness polyurethane engineering plastic.

[0039] Example 7

[0040] Heat 144.21 g of 1,4-cyclohexanedimethanol to 100°C and pour it into a reaction container. Under stirring at 1000 r / min, quickly add 84.75 g of 1,4-cyclohexane diisocyanate and 81.66 g of p-phenylene diisocyanate into the reaction container, and simultaneously add 0.2 g of bismuth neodecanoate as a catalyst. Stir until viscous, then stop stirring, place the polymer together with the reaction container in a 100°C oven for aging for 16 hours to obtain a high-hardness polyurethane engineering plastic.

[0041] Example 8

[0042] Heat 100.95g of 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 27.04g of 1,4-butanediol to 100°C and pour them into a reaction container. Under stirring at 1000r / min, quickly add 272.21g of 3,3'-dimethyl-4,4'-biphenyl diisocyanate to the reaction container, and add 0.008g of stannous octoate as a catalyst. Stir until it becomes viscous, then stop stirring, place the polymer together with the reaction container in a 100°C oven for aging for 16h to obtain a high-hardness polyurethane engineering plastic.

[0043] Comparative Example 1

[0044] Heat 144.21 g of 1,4-cyclohexanedimethanol to 100°C and pour it into a reaction container. Under stirring at 1000 r / min, quickly add 255.24 g of 4,4-diphenylmethane diisocyanate into the reaction container, and simultaneously add 0.2 g of stannous octoate as a catalyst. Stir until it becomes viscous, then stop stirring, place the polymer together with the reaction container in a 100°C oven for aging for 16 hours, and obtain a high-hardness polyurethane engineering plastic.

[0045] Comparative Example 2

[0046] Heat 90.12g of 1,4-butanediol to 100°C and pour it into a reaction container. Under stirring at 1000r / min, quickly add 255.24g of 4,4-diphenylmethane diisocyanate into the reaction container, and simultaneously add 0.2g of stannous octoate as a catalyst. Stir until it becomes viscous, then stop stirring, place the polymer together with the reaction container in a 100°C oven for aging for 16h to obtain a high-hardness polyurethane engineering plastic.

[0047] The pencil hardness test method is as follows: the obtained thermoplastic polyurethane resin product is crushed, injection molded, and then tested according to the standard GB / T 6739-2006.

[0048] The tensile strength evaluation method is as follows: the obtained thermoplastic polyurethane resin product is crushed, injection molded, and then tested according to standard ISO 527.

[0049] The impact strength evaluation method is as follows: the obtained thermoplastic polyurethane resin product is crushed, injection molded, and then tested according to the standard ASTM D256. The thickness of the test piece is 3.2mm, and the notch is milled using a cutter head with an angle radius of 0.25mm. The test temperature is 25℃.

[0050] Table 1 Thermoplastic polyurethane resin performance test results

[0051]

[0052] From the comparison between Example 3 and Comparative Example 1, it can be seen that the use of high rigidity diisocyanate (NDI) can significantly improve the pencil hardness compared with MDI. From the comparison between Comparative Example 1 and Comparative Example 2, it can be seen that the use of alicyclic diol (CHDM) can improve the pencil hardness compared with BDO.

[0053] From the comparison between Example 4 and Example 8, it can be seen that after replacing part of the alicyclic diol with butanediol, the pencil hardness of the product is slightly reduced, but due to the reduction of the rigid structure of the main chain, a lower processing temperature can be obtained.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A polyurethane engineering plastic with a scratch-resistant body, characterized in that: It is polymerized from the following raw materials in percentage by weight: 45 wt% to 68 wt% of rigid diisocyanate, 32 wt% to 55 wt% of small molecule diol, and 10 to 2000 ppm of catalyst, the sum of the percentages of the raw materials being 100%; Among them, the rigid diisocyanate has two characteristics: (1) Both isocyanate groups are directly attached to the aliphatic or aromatic ring; (2) There is no flexible group connecting the alicyclic ring and the aromatic ring in the molecule, and the flexible group includes: methylene and ether bond; The small molecule diol contains an ester ring.

2. The scratch-resistant polyurethane engineering plastic according to claim 1, characterized in that: The rigid diisocyanate is selected from at least one of p-phenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,4-cyclohexane diisocyanate, and 3,3'-dimethyl-4,4'-biphenyl diisocyanate.

3. The scratch-resistant polyurethane engineering plastic according to claim 1, characterized in that: The small molecule diol is selected from at least one of isosorbide, tricyclo[5.2.1,2,6]decanedimethanol, 1,4-cyclohexanedimethanol, and 2,2,4,4-tetramethyl-1,3-cyclobutanediol.

4. The scratch-resistant polyurethane engineering plastic according to claim 1, characterized in that: The catalyst is an organotin or organobismuth esterification catalyst.

5. The scratch-resistant polyurethane engineering plastic according to claim 1, characterized in that: The catalyst is stannous octoate or bismuth neodecanoate.

6. The scratch-resistant polyurethane engineering plastic according to claim 1, characterized in that: The linear small molecule diol is used to partially replace the small molecule diol containing an ester ring.

7. A method for preparing a polyurethane engineering plastic with a scratch-resistant body, characterized in that: include: Heat the small molecule diol to 80-150°C, add rigid diisocyanate and catalyst, stir until viscous, then stop stirring, and mature at 90-120°C to obtain the product.

8. The method for preparing the scratch-resistant polyurethane engineering plastic according to claim 7, characterized in that: The stirring speed is 500-1500 r / min.

9. The method for preparing the scratch-resistant polyurethane engineering plastic according to claim 7, characterized in that: The aging time is 12 hours to 24 hours.

10. Application of the scratch-resistant polyurethane engineering plastic according to any one of claims 1 to 6 in the fields of construction, automobiles, aviation industry, thermal insulation, and mechanical parts.

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