Low hardness self-whitening polyurethane elastomer composition for hand, and preparation method and application thereof

Abstract

The present application belongs to the technical field of polyurethane elastomer, and particularly relates to a low-hardness self-whitening polyurethane elastomer composition for hand processing, a preparation method and application thereof. The composition is composed of A component, B component and C component in a mass ratio of 100:100:(0-500), wherein the A component is a curing agent, including polyether polyol 1, a chain extender, an antioxidant and a catalyst; the B component is an isocyanate-terminated polyurethane prepolymer, including polyether polyol 2 and diisocyanate; and the C component is a mixture of polyether polyol 3 and plasticizer, antioxidant and catalyst. The hardness of the polyurethane elastomer is adjusted by adjusting the amount of C component, and the product has low hardness, good toughness and comfortable hand feeling. After reaction and curing, the product is self-whitened and has a milky white appearance, which is convenient for color adjustment. The present application also provides a preparation method and application thereof.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polyurethane elastomers, and particularly relates to a low-hardness self-whitening polyurethane elastomer composition for hand-made toys and a preparation method and application thereof. BACKGROUND

[0002] Hand-made toys, as a derivative of popular culture such as animation and games, have received extensive attention and love worldwide in recent years. In the production of hand-made toys, the selection of materials is crucial. Common materials include PVC (polyvinyl chloride), PU resin, ABS plastic, etc. These materials have different characteristics and bring different textures and expressiveness to hand-made toys. PU, which stands for polyurethane, is a high polymer material formed by polyol and polyisocyanate through polycondensation reaction and has excellent mechanical properties. After curing, its physical properties are stronger than those of PVC and ABS, and it is not easily deformed. PU has the advantages of comfortable hand feeling, strong durability, anti-aging, wear resistance, and long service life. In addition, PU has strong plasticity and does not need to be heated and melted. It can be used with silicone molds, which is lower in mold opening cost and simpler in production compared to metal molds used for PVC.

[0003] Chinese Patent CN119331200A discloses a preparation method of a high-temperature-resistant self-whitening polyurethane elastomer for hand-made toys. The hand-made toy-resistant self-whitening polyurethane elastomer is composed of A component and B component in a mass ratio of 100: (95-105). The A component is a curing agent, which includes the following raw materials: polyether polyol 1, polyether polyol 2, antioxidant, and catalyst. The B component is an isocyanate-terminated polyurethane prepolymer, which includes the following raw materials: polyether polyol 3 and diisocyanate. The hand-made toy-resistant self-whitening polyurethane elastomer has excellent mechanical properties, good high-temperature resistance and aging resistance, self-whitening reaction, comfortable hand feeling, and a product appearance that is milky white, which facilitates color adjustment. When applied to hand-made toy production, the product has high temperature resistance, good toughness, is not easy to break or discolor, and has a variety of color changes. However, its room temperature hardness is too high, with a hardness of more than 80D at room temperature of 25℃, resulting in poor hand feeling. In addition, its elongation at break is only about 20-30%, which is poor in toughness and easy to break. These shortcomings seriously limit its application range.

[0004] Therefore, it is necessary to further study polyurethane elastomer materials and develop a polyurethane elastomer with adjustable hardness, soft hand feeling, low hardness, and good toughness, so that it can be better applied to hand-made toy production. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a low-hardness self-whitening polyurethane elastomer compound for hand processing, which adjusts the hardness of the polyurethane elastomer by adjusting the amount of C material added, has low hardness, good toughness, comfortable hand feeling, and is self-whitening after curing, and has a milky white appearance, which facilitates color adjustment; the present application also provides a preparation method and application thereof.

[0006] The purpose of the present application is achieved by the following technical solutions:

[0007] In one aspect, the present application provides a low-hardness self-whitening polyurethane elastomer compound for hand processing, which is composed of A component, B component and C component in a mass ratio of 100:100:(0-500), wherein:

[0008] The A component is a curing agent, which includes the following raw materials in mass fraction: 60-84.8 parts of polyether polyol 1, 14-38 parts of chain extender, 0.9-1.5 parts of antioxidant, and 0.3-0.5 parts of catalyst;

[0009] The B component is an isocyanate-terminated polyurethane prepolymer, which includes the following raw materials in mass fraction: 30-38 parts of polyether polyol 2, and 62-70 parts of diisocyanate;

[0010] The C component is a mixture of polyether polyol 3, plasticizer, antioxidant and catalyst, which includes the following raw materials in mass fraction: 73.2-75 parts of polyether polyol 3, 23-25 parts of plasticizer, 0.9-1.5 parts of antioxidant, and 0.3-0.5 parts of catalyst;

[0011] The polyether polyol 1 is prepared by chain extension reaction of ethylene glycol as a starter with ethylene oxide, has a functionality of 2, a hydroxyl value of 75-140, and a number average molecular weight of 800-1500;

[0012] The polyether polyol 2 is a polyether polyol with a functionality of 2, a hydroxyl value of 14-28, and a number average molecular weight of 4000-8000;

[0013] The polyether polyol 3 is a polyether polyol with a functionality of 2-3, a hydroxyl value of 18.5, and a number average molecular weight of 6000-9000;

[0014] The chain extender is one or more of MOCA, DMTDA, BDO and DPG;

[0015] The diisocyanate is a mixture of aliphatic isocyanate and aromatic isocyanate in any ratio, the aliphatic isocyanate is at least one of IPDI and HMDI, and the aromatic isocyanate is at least one of pure MDI and liquefied MDI;

[0016] The plasticizer is one or more of DOTP, DOS, TXIB, 988SG.

[0017] Preferably, the polyether polyol 1 is one or more of PEG800, PEG1000, PEG1500.

[0018] Preferably, the polyether polyol 2 is one or more of C240, C260, C280.

[0019] Preferably, the polyether polyol 3 is one or more of C260, 3900, PEG6000, PE-4060.

[0020] Preferably, the antioxidant is one or more of UV-292, UV-01, 1076.

[0021] Preferably, the catalyst is one or more of CUCAT-E01, CUCAT-E02, CUCAT-E05.

[0022] In another aspect, the present application provides a preparation method of the low-hardness self-whitening hand model polyurethane elastomer composition, comprising the following steps:

[0023] (1) Preparation of A component: polyether polyol 1, chain extender, catalyst and antioxidant are put into a reaction container, stirred uniformly, nitrogen protection, heated to 95-100℃, vacuum dehydration to moisture content <0.05wt.%, cooled and sealed for storage, to obtain A component;

[0024] (2) Preparation of B component: diisocyanate is added to a reaction container, nitrogen protection, polyether polyol 2 is added, heated and reacted, after the reaction, vacuum degassing and cooling, to obtain B component with isocyanate content of 21.04-21.2wt.%;

[0025] (3) Preparation of C component: polyether polyol 3, plasticizer, catalyst and antioxidant are put into a reaction container, stirred uniformly, nitrogen protection, heated to 95-100℃, vacuum dehydration to moisture content <0.05wt.%, cooled and sealed for storage, to obtain C component.

[0026] Preferably, in step (2), the reaction temperature is 85-95℃ and the reaction time is 3-5h.

[0027] In addition, the present application also provides the application of the low-hardness self-whitening hand model polyurethane elastomer composition, A component, B component and C component are mixed uniformly, poured into a mold of different shapes, cured and formed, and a hand model is prepared after opening the mold and room temperature vulcanization.

[0028] The mixing temperature is kept at 25-35 DEG C when the A component, the B component and the C component are mixed uniformly.

[0029] When being solidified and formed by being cast in molds of different shapes, the operation time is 8-10 min and the mold opening time is 30-60 min.

[0030] When the hand-made products are prepared, different pigments can be added in the combined material to prepare the hand-made products with rich colors, and the products can be dyed after being demolded.

[0031] Compared with the prior art, the low-hardness self-whitening hand-made polyurethane elastomer combined material has the following beneficial effects:

[0032] (1) The high-activity small molecule chain extender and the EO group chain extended polyether polyol are introduced in the A component, the low-activity PO group chain extended polyether polyol is used to modify the isocyanate group in the B component, the activities of the A component and the B component are obviously different, and the different reaction activities are not synchronized, so that the polyurethane elastomer after being solidified not only presents the milky white color, but also has excellent mechanical properties and warm touch.

[0033] (2) The macromolecular polyether polyol is used to modify the isocyanate in the B component, so that the free isocyanate in the B component is increased, the free isocyanate has high activity, the molecular chain of the isocyanate modified by the macromolecular polyether has low activity, the appearance of the product after being solidified is more likely to be white. In addition, the polyether polyol has long molecular chain and good flexibility, so that the toughness of the elastomer after being solidified is excellent. Furthermore, the aliphatic isocyanate and the aromatic isocyanate are used in the B component, the aromatic isocyanate has high activity and the aliphatic isocyanate has low activity, the activity difference in the reaction process makes the elastomer after being solidified more likely to be white, the addition of the aliphatic isocyanate further improves the aging resistance and yellowing resistance of the product, so that the product has excellent weather resistance.

[0034] (3) The super-macromolecular polyol and the plasticizer are introduced in the C component, the proportion of the A component and the B component is fixed, and the addition of the super-macromolecular polyether polyol and the plasticizer in the C component can significantly reduce the hardness of the polyurethane elastomer. The proportion of the soft segment and the hard segment in the polyurethane molecular chain segment can be adjusted by adjusting the addition amount of the C component, so that the elastomer with a Shore A value of 20-93 degrees can be prepared.

[0035] (4) The preparation method of the low-hardness self-whitening hand-made polyurethane elastomer combined material has simple process flow and good flowability of each component, so that the hand casting is convenient. In addition, the prepared product is cast in different molds to prepare the hand-made products, the operation is simple, the product has the milky white base, and the color adjustment is convenient. DETAILED DESCRIPTION

[0036] The application will be further described in connection with the following examples and comparative examples. The raw materials used in the examples and comparative examples are all conventional commercially available raw materials unless otherwise specified. The process methods used are conventional methods in the art unless otherwise specified. The parts referred to in the examples and comparative examples are all parts by mass.

[0037] The raw materials used in the examples and comparative examples are as follows:

[0038] MOCA: 3,3'-dichloro-4,4'-diaminodiphenyl methane, Suzhou Xiangyuan New Material Co., Ltd.;

[0039] DMTDA: dimethylthio toluene diamine, Suzhou Xiangyuan New Material Co., Ltd.;

[0040] BDO: 1,4-butanediol, Xinjiang Meike Chemical Co., Ltd.;

[0041] DPG: dipropylene glycol, Xinjiang Meike Chemical Co., Ltd.;

[0042] PEG800: ethylene glycol as starter, EO chain extension, hydroxyl value 140, functionality 2, number average molecular weight 800, Liaoning Ok Chemical Co., Ltd.;

[0043] PEG1000: ethylene glycol as starter, EO chain extension, hydroxyl value 112, functionality 2, number average molecular weight 1000, Liaoning Ok Chemical Co., Ltd.;

[0044] PEG1500: ethylene glycol as starter, EO chain extension, hydroxyl value 75, functionality 2, number average molecular weight 1500, Liaoning Ok Chemical Co., Ltd.;

[0045] PEG6000: ethylene glycol as starter, EO chain extension, hydroxyl value 18.5, functionality 2, number average molecular weight 6000, Liaoning Ok Chemical Co., Ltd.;

[0046] PE-4060: polyester polyol, polycondensation of 1,4-butanediol and adipic acid, hydroxyl value 18.5, functionality 2, number average molecular weight 6000, Shandong Ynuo Wei Polyurethane Co., Ltd.;

[0047] C208: ethylene glycol as starter, PO chain extension, hydroxyl value 140, functionality 2, number average molecular weight 800, Shandong Ynuo Wei New Material Co., Ltd.;

[0048] C240: hydroxyl value 28, functionality 2, number average molecular weight 4000, Shandong Ynuo Wei New Material Co., Ltd.;

[0049] C260: hydroxyl value 18.5, functionality 2, number average molecular weight 6000, Shandong Ynuo Wei New Material Co., Ltd.;

[0050] C280: hydroxyl value 14, functionality 2, number average molecular weight 8000, Shandong Yinaowei New Material Co., Ltd.;

[0051] 3900: hydroxyl value 18.5, functionality 3, number average molecular weight 9000, Shandong Yinaowei New Material Co., Ltd.;

[0052] 83E: hydroxyl value 28, functionality 3, number average molecular weight 6000, Shandong Yinaowei New Material Co., Ltd.;

[0053] HMDI: 4,4-dicyclohexylmethane diisocyanate, Wanhua Chemical Group Co., Ltd.;

[0054] IPDI: isophorone diisocyanate, Wanhua Chemical Group Co., Ltd.;

[0055] pure MDI: diphenylmethane diisocyanate, Wanhua Chemical Group Co., Ltd.;

[0056] liquefied MDI: carbodiimide-modified diphenylmethane diisocyanate, Wanhua Chemical Group Co., Ltd.;

[0057] DOTP: dioctyl terephthalate, Lanfan Group Co., Ltd.;

[0058] DOS: dioctyl sebacate, Lanfan Group Co., Ltd.;

[0059] TXIB: trimethylpentanediol diisobutyrate, Shanghai Kaijin Chemical Co., Ltd.;

[0060] 988SG: dipropylene glycol dibenzoate, Shanghai Kaijin Chemical Co., Ltd.;

[0061] UV-292, UV-01, 1076: BASF (China) Co., Ltd.;

[0062] CUCAT-E01, CUCAT-E02, CUCAT-E05: Guangzhou Yourun Synthetic Material Co., Ltd.

[0063] The preparation method of the low-hardness self-whitening hand polyurethane elastomer comprises the following steps:

[0064] (1) Preparation of component A: add 60-84.8 parts of polyether polyol 1, 14-38 parts of chain extender, 0.3-0.5 parts of catalyst and 0.9-1.5 parts of antioxidant into a four-necked flask, stir uniformly, protect with nitrogen, heat to 95-100℃, dehydrate to a water content of <0.05wt.% under vacuum-0.01MPa, and then cool and seal to obtain component A;

[0065] (2) Preparation of B component: 62-70 parts of diisocyanate was added into a four-necked flask, nitrogen protection, 30-38 parts of polyether polyol 2 was added, heated to 85-95℃, and kept for 3-5h. After the reaction was completed, vacuum extraction was performed to -0.01 MPa for 1h, and then the temperature was lowered to obtain B component with isocyanate content of 21.04-21.2wt.%;

[0066] (3) Preparation of C component: 73.2-75 parts of polyether polyol 3, 23-25 parts of plasticizer, 0.3-0.5 parts of catalyst and 0.9-1.5 parts of antioxidant were added into a four-necked flask, stirred uniformly, heated to 95-100℃ under nitrogen protection, vacuum extraction was performed to -0.01 MPa for dehydration until the moisture content was less than 0.05wt.%, and then the temperature was lowered to obtain C component;

[0067] (4) In use, A component, B component and C component were mixed uniformly at a mass ratio of 100:100:(0-500) at a mixing temperature of 25-35℃, poured into a preheated mold to solidify and form, the operation time was 8-10min, the mold was opened after 30-60min, and then room temperature vulcanization was performed for 7 days to obtain low-hardness self-whitening hand-held polyurethane elastomer with adjustable hardness.

[0068] Example 1

[0069] The preparation method of the low-hardness self-whitening hand-held polyurethane elastomer, the steps are as follows:

[0070] (1) Preparation of A component: 14 parts of BDO, 20 parts of PEG800, 64.8 parts of PEG1000, 0.3 parts of catalyst CUCAT-E01, 0.3 parts of antioxidant UV-292, 0.3 parts of antioxidant UV-01 and 0.3 parts of antioxidant 1076 were added into a four-necked flask, stirred uniformly, heated to 95℃ under nitrogen protection, vacuum extraction was performed to -0.01 MPa for dehydration until the moisture content was less than 0.05wt.%, and then the temperature was lowered to obtain A component;

[0071] (2) Preparation of B component: 15 parts of IPDI and 55 parts of liquefied MDI were added into a four-necked flask, nitrogen protection, 30 parts of C240 was added, heated to 85℃, and kept for 3h. After the reaction was completed, vacuum extraction was performed to -0.01 MPa for 1h, and then the temperature was lowered to obtain B component with isocyanate content of 21.2wt.%;

[0072] (3) Preparation of C component: add 73.8 parts of C260, 25 parts of plasticizer TXIB, 0.3 parts of catalyst CUCAT-E01, 0.3 parts of antioxidant UV-292, 0.3 parts of antioxidant UV-01, 0.3 parts of antioxidant 1076 into a four-necked flask, stir uniformly, protect with nitrogen, heat to 97.5±2.5℃, dehydrate to moisture content <0.05wt.% under vacuum-0.01MPa, cool and seal for storage, to obtain C component;

[0073] (4) In use, mix A component, B component and C component uniformly in a mass ratio of 100:100:(0-500), the mixing temperature is 35℃, pour into preheated mold to solidify and form, the operation time is 10min, open the mold after 60min, and room temperature vulcanize for 7 days after opening the mold, to obtain low-hardness self-whitening polyurethane elastomer for hand.

[0074] Example 2

[0075] The preparation method of the low-hardness self-whitening polyurethane elastomer for hand, the steps are as follows:

[0076] (1) Preparation of A component: add 20 parts of DPG, 78.2 parts of PEG800, 0.3 parts of catalyst CUCAT-E02, 0.5 parts of antioxidant UV-292, 0.5 parts of antioxidant UV-01, 0.5 parts of antioxidant 1076 into a four-necked flask, stir uniformly, protect with nitrogen, heat to 95℃, dehydrate to moisture content <0.05wt.% under vacuum-0.01MPa, cool and seal for storage, to obtain A component;

[0077] (2) Preparation of B component: add 20 parts of HMDI, 45 parts of pure MDI into a four-necked flask, protect with nitrogen, add 35 parts of C260, heat to 90℃, keep for 3h, after reaction, deaerate for 1h under vacuum-0.01MPa, cool, to obtain B component with isocyanate content of 21.04wt.%;

[0078] (3) Preparation of C component: add 73.2 parts of 3900, 25 parts of plasticizer DOS, 0.3 parts of catalyst CUCAT-E02, 0.5 parts of antioxidant UV-292, 0.5 parts of antioxidant UV-01, 0.5 parts of antioxidant 1076 into a four-necked flask, stir uniformly, protect with nitrogen, heat to 97.5±2.5℃, dehydrate to moisture content <0.05wt.% under vacuum-0.01MPa, cool and seal for storage, to obtain C component;

[0079] (4) using, A component, B component, C component are mixed uniformly according to the mass ratio 100:100:(0-500), the mixing temperature is 25 DEG C, pour into the preheated mold and solidify into shape, the operable time is 8 min, open the mold after 40 min, after opening the mold, room temperature vulcanization 7 days, the low hardness self-white hand handle polyurethane elastomer is obtained.

[0080] Example 3

[0081] The preparation method of the low hardness self-white hand handle polyurethane elastomer, the steps are as follows:

[0082] (1) the preparation of A component: in four-necked flask, 6 parts of BDO, 30 parts of DMTDA, 62.2 parts of PEG1500, 0.3 parts of catalyst CUCAT-E05, 0.5 parts of antioxidant UV-292, 0.5 parts of antioxidant UV-01, 0.5 parts of antioxidant 1076, stirring uniformly, nitrogen protection, heating to 95 DEG C, vacuum dehydration to moisture content <0.05wt.%-0.01MPa, cooling and sealing, A component is obtained;

[0083] (2) the preparation of B component: in four-necked flask, 30 parts of HMDI, 40 parts of liquefied MDI, nitrogen protection, 30 parts of C280 are added, heating to 95 DEG C, and reaction for 5h, after reaction, vacuum degassing for 1h to-0.01MPa, cooling, B component with isocyanate content of 21.05wt.% is obtained;

[0084] (3) the preparation of C component: in four-necked flask, 75 parts of PEG6000, 10 parts of plasticizer DOTP, 13.2 parts of TXIB, 0.3 parts of catalyst CUCAT-E05, 0.5 parts of antioxidant UV-292, 0.5 parts of antioxidant UV-01, 0.5 parts of antioxidant 1076, stirring uniformly, nitrogen protection, heating to 97.5±2.5 DEG C, vacuum dehydration to moisture content <0.05wt.%-0.01MPa, cooling and sealing, C component is obtained;

[0085] (4) using, A component, B component, C component are mixed uniformly according to the mass ratio 100:100:(0-500), the mixing temperature is 25 DEG C, pour into the preheated mold and solidify into shape, the operable time is 8 min, open the mold after 40 min, after opening the mold, room temperature vulcanization 7 days, the low hardness self-white hand handle polyurethane elastomer is obtained.

[0086] Example 4

[0087] The preparation method of the low hardness self-white hand handle polyurethane elastomer, the steps are as follows:

[0088] (1) Preparation of A component: add 13 parts of DPG, 25 parts of MOCA, 60 parts of PEG1000, 0.2 parts of catalyst CUCAT-E01, 0.3 parts of catalyst CUCAT-E02, 0.5 parts of antioxidant UV-292, 0.5 parts of antioxidant UV-01, 0.5 parts of antioxidant 1076 into a four-necked flask, stir uniformly, protect with nitrogen, heat to 95℃, dehydrate to moisture content <0.05wt.% under vacuum-0.01MPa, cool and seal, to obtain A component;

[0089] (2) Preparation of B component: add 22 parts of IPDI, 40 parts of pure MDI into a four-necked flask, protect with nitrogen, add 20 parts of C280, 18 parts of C240, heat to 95℃, react for 4h, after reaction, deaerate for 1h under vacuum-0.01MPa, cool, to obtain B component with isocyanate content of 21.17wt.%;

[0090] (3) Preparation of C component: add 75 parts of PE-4060, 23 parts of plasticizer 988SG, 0.3 parts of catalyst CUCAT-E05, 0.5 parts of antioxidant UV-292, 0.5 parts of antioxidant UV-01, 0.5 parts of antioxidant 1076 into a four-necked flask, stir uniformly, protect with nitrogen, heat to 97.5±2.5℃, dehydrate to moisture content <0.05wt.% under vacuum-0.01MPa, cool and seal, to obtain C component;

[0091] (4) In use, mix A component, B component and C component uniformly according to mass ratio of 100:100:(0-500), the mixing temperature is 30℃, pour into preheated mold to solidify and form, the operation time is 8min, open the mold after 30min, and vulcanize at room temperature for 7 days after opening the mold, to obtain low-hardness self-whitening hand polyurethane elastomer.

[0092] Comparative Example 1

[0093] On the basis of Example 1, the polyether polyol in B component is replaced by 83E.

[0094] Comparative Example 2

[0095] On the basis of Example 2, the polyether polyol in A component is replaced by C208.

[0096] Comparative Example 3

[0097] On the basis of Example 2, the polyether polyol in C component is replaced by C208.

[0098] Comparative Example 4

[0099] On the basis of Example 2, the isocyanate in B component is replaced by pure MDI.

[0100] In the above Examples 1-4 and Comparative Examples 1-4, the mixing ratio of the A component, the B component, and the C component is shown in Table 1.

[0101] Comparative Example 5

[0102] Example 1 in the toy high-temperature-resistant self-whitening polyurethane elastomer and its preparation method and application described in patent CN119331200A.

[0103] The polyurethane elastomers prepared in each example and comparative example were tested for performance, and the hardness and elongation at break were tested according to GB / T528-2009 and GB / T531-1999; the whiteness grade was tested according to the general method for testing the whiteness of inorganic chemical products in GB / T23774-2009; and the yellowing resistance grade was tested according to GB / T23983-2009.

[0104] The test results are shown in Table 1.

[0105] Table 1 Test results

[0106]

[0107] Note: In the above table, the hardness of Comparative Example 5 is 80D.

[0108] As can be seen from Table 1, in Example 3, the B component uses C280 to synthesize a prepolymer, which has the largest molecular weight and the most free isocyanate in the synthesized prepolymer, so the polyurethane elastomer prepared therefrom has the whitest appearance and the highest whiteness grade.

[0109] Compared with Example 1, in Comparative Example 1, the polyether polyol of the B component is replaced by 83E, and the isocyanate content is consistent with that of Example 1, but due to its high functionality and high activity, the polyurethane elastomer prepared therefrom has a semi-transparent appearance and insufficient whiteness.

[0110] Compared with Example 2, in Comparative Example 2, the polyether polyol of the A component is replaced by C208, which has poor crystallinity, so the hardness of the elastomer prepared at different ratios is lower, and the hardness is too low when the low-hardness 20A and 30A ratios are compared, the molding is poor, and it cannot meet the customer's requirements, and since it is a PO group chain extender, the appearance whiteness of the cured product is significantly lower than that of Example 2.

[0111] Compared with Example 2, the C component polyol in Comparative Example 3 is replaced by C208 from 3900. Due to the high hydroxyl value of C208, the hydroxyl group is excessive in the curing process at different ratios, and the hydroxyl / isocyanate ratio in the reaction system is seriously out of balance, so the hardness after curing at different ratios is lower than that of Example 2. When the ratio is 30A and 20A, it cannot be formed due to the too low hydroxyl / isocyanate index, which cannot meet the customer's requirements.

[0112] Compared with Example 2, the isocyanate in B component in Comparative Example 4 is replaced by pure MDI. Since pure MDI has stronger crystallinity than HMDI in Example 2, the hardness of the polyurethane elastomer prepared by it is generally higher than that of Example 2. However, due to the existence of a large number of benzene rings in the molecular chain of pure MDI which are easy to be oxidized, it performs the worst in the yellowing resistance test.

[0113] Comparative Example 5 is the high-temperature-resistant self-whitening polyurethane hand elastic body example 1 disclosed in patent CN119331200A, which has a hardness of 80D, but an elongation of only 24%, and poor toughness.

Claims

1. A low hardness self-whitening polyurethane elastomer compound for hand, characterized in that: consists of A component, B component and C component in a mass ratio of 100:100:(0-500), and the mass of C component is not 0, wherein: The A component is a curing agent, and includes the following raw materials in mass fractions: 60-84.8 parts of polyether polyol 1, 14-38 parts of chain extender, 0.9-1.5 parts of antioxidant, and 0.3-0.5 parts of catalyst; The B component is an isocyanate-terminated polyurethane prepolymer, and includes the following raw materials in mass fractions: 30-38 parts of polyether polyol 2, and 62-70 parts of diisocyanate; The C component is a mixture of polyether polyol 3 and plasticizer, antioxidant and catalyst, and includes the following raw materials in mass fractions: 73.2-75 parts of polyether polyol 3, 23-25 parts of plasticizer, 0.9-1.5 parts of antioxidant, and 0.3-0.5 parts of catalyst; The polyether polyol 1 is prepared by chain extension reaction of ethylene glycol as a starter with ethylene oxide, has a functionality of 2, a hydroxyl value of 75-140 mgKOH / g, and a number average molecular weight of 800-1500; The polyether polyol 2 is one or more of C240, C260 and C280; and the polyether polyol 3 is a polyether polyol having a functionality of 2-3, a hydroxyl value of 18.5 mgKOH / g, and a number average molecular weight of 6000-9000; The chain extender is one or more of MOCA, DMTDA, BDO and DPG; The diisocyanate is a mixture of aliphatic isocyanate and aromatic isocyanate in any ratio, the aliphatic isocyanate is at least one of IPDI and HMDI, and the aromatic isocyanate is at least one of pure MDI and liquefied MDI; The plasticizer is one or more of DOTP, DOS, TXIB and 988SG.

2. The low hardness self- whitening hand for polyurethane elastomer composition according to claim 1, characterized in that: The polyether polyol 1 is one or more of PEG800, PEG1000 and PEG1500.

3. The low hardness self- whitening hand for polyurethane elastomer composition according to claim 1, characterized in that: The polyether polyol 3 is one or both of C260 and PEG6000.

4. The low hardness self- whitening hand for polyurethane elastomer composition according to claim 1, characterized in that: The antioxidant is one or more of UV-292, UV-01 and 1076.

5. The low hardness self- whitening hand for polyurethane elastomer composition according to claim 1, characterized in that: The catalyst is one or more of CUCAT-E01, CUCAT-E02 and CUCAT-E05.

6. A process for the preparation of a low hardness self-whitening polyurethane elastomer compound for hand according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: (1) Preparation of the A component: the polyether polyol 1, chain extender, catalyst and antioxidant are put into a reaction container, stirred uniformly, protected by nitrogen, heated to 95-100℃, vacuum dehydrated to a water content of <0.05wt.%, and then cooled and sealed to obtain the A component; (2) Preparation of the B component: the diisocyanate is added into a reaction container, protected by nitrogen, and then the polyether polyol 2 is added, heated and reacted, after the reaction, vacuum deaerated, and then cooled to obtain the B component with an isocyanate content of 21.04-21.2wt.%; (3) Preparation of the C component: the polyether polyol 3, plasticizer, catalyst and antioxidant are put into a reaction container, stirred uniformly, protected by nitrogen, heated to 95-100℃, vacuum dehydrated to a water content of <0.05wt.%, and then cooled and sealed to obtain the C component.

7. The process for preparing a low hardness self- whitening hand for polyurethane elastomer compound according to claim 6, characterized in that: In step (2), the temperature of the reaction is 85-95 DEG C, and the reaction time is 3-5 hours.

8. Use of a low hardness self-whitening polyurethane elastomer composition according to any one of claims 1 to 5, characterized in that: The A component, the B component and the C component are mixed uniformly, and then poured into a mold of different shape to be cured and formed, and after the mold is opened, the vulcanization is carried out at room temperature to prepare the hand.

9. Use of a low hardness self- whitening hand for polyurethane elastomer composition according to claim 8, characterized in that: When the A component, the B component and the C component are mixed uniformly, the mixing temperature is kept at 25-35 DEG C; when poured into a mold of different shape to be cured and formed, the operation time is 8-10 minutes, and the mold opening time is 30-60 minutes.

Images