A colorless and transparent polyurethane elastomer and preparation method thereof

Abstract

The present invention belongs to the technical field of polyurethane elastomers, and specifically relates to a colorless and transparent polyurethane elastomer and a preparation method thereof. The present invention provides a colorless and transparent polyurethane elastomer, and the preparation raw materials include polyols, isocyanates, chain extenders and catalysts; the isocyanates include alicyclic isocyanates and / or aliphatic isocyanates; the chain extender is tricyclo[5.2.1.0(2,6)]decanedimethanol. In the present invention, cyclo[5.2.1.0(2,6)]decanedimethanol (TDDM) with an asymmetric alicyclic structure is used as a chain extender, and its high steric effect is utilized to form a synergistic effect with alicyclic (or aliphatic) isocyanates, thereby inhibiting the crystallization of the hard segment in the polyurethane elastomer and reducing the size of the ordered region, thereby making the polyurethane elastomer provided by the present invention have excellent mechanical properties on the basis of meeting the colorless and transparent requirements.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane elastomers, and particularly relates to a colorless and transparent polyurethane elastomer and a preparation method thereof. Background Art

[0002] Polyurethane is the abbreviation of polyurethane. All polymer compounds containing many repeated carbamate groups on the main chain of the polymer are generally called polyurethane. Generally, it is polymerized by polymer polyol isocyanate and chain extender. It is a block copolymer linear polymer compound composed of soft segment and hard segment. Generally, long-chain diol constitutes the soft segment, while the hard segment is composed of isocyanate and chain extender. Due to the thermodynamic incompatibility of hard segment and soft segment, polyurethane has a relatively special microphase separation structure of hard segment and soft segment phase separation. The soft segment gives the product properties such as flexibility, resilience and flexural properties, while the hard segment gives the product excellent mechanical properties and chemical resistance.

[0003] At present, the basic theoretical research on the relationship between the aggregate structure and performance of polyurethane elastomers mainly focuses on non-transparent systems. However, for transparent polyurethane elastomers, the field involved is optical requirements with higher performance requirements, and there are few reports on their synthesis and theoretical research.

[0004] Related art discloses the use of polytetrahydrofuran and polyisocyanate to prepare a polyurethane elastomer with good tensile strength, elongation at break and modulus of tensile strength. This method can prepare a polyurethane elastomer with good performance, but it cannot meet the optical performance requirements - the product is an opaque polyurethane elastomer. Therefore, it is urgent to obtain a colorless and transparent polyurethane elastomer with excellent mechanical properties. Summary of the invention

[0005] The purpose of the present invention is to provide a colorless and transparent polyurethane elastomer and a preparation method thereof. The polyurethane elastomer provided by the present invention has excellent mechanical properties on the basis of being colorless and transparent.

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

[0007] The invention provides a colorless and transparent polyurethane elastomer, the preparation raw materials of which include polyol, isocyanate, chain extender and catalyst;

[0008] The isocyanate includes alicyclic isocyanate and / or aliphatic isocyanate;

[0009] The chain extender is tricyclo[5.2.1.0(2,6)]decanedimethanol, having the structure shown in Formula 1;

[0010]

[0011] Preferably, the raw materials for preparation include, by weight: 100 to 150 parts of polyol, 30 to 158 parts of isocyanate, 20 to 88 parts of chain extender and 0.2 to 4 parts of catalyst.

[0012] Preferably, the number average molecular weight of the polyol is 1000-1500.

[0013] Preferably, the polyol includes one or more of polybutylene glycol, polypropylene glycol, polycaprolactone diol and polycarbonate diol.

[0014] Preferably, the isocyanate includes one or more of 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate and cyclohexane dimethylene diisocyanate.

[0015] Preferably, the catalyst comprises dibutyltin dilaurate.

[0016] The present invention also provides a method for preparing the colorless and transparent polyurethane elastomer described in the above technical solution, comprising the following steps:

[0017] Dehydrating the polyol to obtain a dehydrated polyol;

[0018] The dehydrated polyol, isocyanate and catalyst are mixed and prepolymerized to obtain a prepolymer;

[0019] The prepolymer and the chain extender are mixed, and then vulcanized and aged in sequence to obtain the colorless and transparent polyurethane elastomer.

[0020] Preferably, the prepolymerization temperature is 70-80° C. and the time is 1-2 hours.

[0021] Preferably, the vulcanization temperature is 80-120° C. and the time is 2-5 hours.

[0022] Preferably, the aging temperature is 50-80° C. and the time is 12-24 hours.

[0023] The present invention provides a colorless and transparent polyurethane elastomer, and the raw materials for preparing the polyurethane elastomer include polyol, isocyanate, chain extender and catalyst; the isocyanate includes alicyclic isocyanate and / or aliphatic isocyanate; the chain extender is tricyclo[5.2.1.0(2,6)]decanedimethanol, and has a structure shown in Formula 1. In the present invention, cyclo[5.2.1.0(2,6)]decanedimethanol (TDDM) with an asymmetric alicyclic structure is used as a chain extender, and its high steric effect is utilized to form a synergistic effect with alicyclic (or aliphatic) isocyanate, thereby inhibiting the crystallization of hard segments in the polyurethane elastomer and reducing the size of the ordered region; at the same time, the rigidity of the alicyclic structure of TDDM is greater than that of commonly used aliphatic alcohol chain extenders (such as 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol), which is beneficial to the hard segment unit to exert a reinforcing effect, thereby making the polyurethane elastomer provided by the present invention have excellent mechanical properties on the basis of meeting the colorless and transparent requirements.

[0024] The present invention also provides a method for preparing the colorless and transparent polyurethane elastomer described in the above technical solution, comprising the following steps: dehydrating a polyol to obtain a dehydrated polyol; mixing the dehydrated polyol, an isocyanate and a catalyst, and prepolymerizing to obtain a prepolymer; mixing the prepolymer and a chain extender, and sequentially vulcanizing and aging to obtain the colorless and transparent polyurethane elastomer. The preparation method provided by the present invention is simple, and by adjusting the amount of each component, a solvent-free green synthesis of a colorless and transparent polyurethane elastomer with adjustable performance is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 1 is the transmittance curve of the polyurethane elastomer obtained in the examples and comparative examples. DETAILED DESCRIPTION

[0026] The invention provides a colorless and transparent polyurethane elastomer, the preparation raw materials of which include polyol, isocyanate, chain extender and catalyst;

[0027] The isocyanate includes alicyclic isocyanate and / or aliphatic isocyanate;

[0028] The chain extender is tricyclo[5.2.1.0(2,6)]decanedimethanol, having the structure shown in Formula 1;

[0029]

[0030] In parts by mass, the raw materials for preparing the colorless and transparent polyurethane elastomer provided by the present invention preferably include 100 to 150 parts of polyols, more preferably 110 to 140 parts, and more preferably 120 to 130 parts. In the present invention, the number average molecular weight of the polyols is preferably 1000 to 1500, more preferably 1100 to 1400, and more preferably 1200 to 1300. In the present invention, the polyols preferably include one or more of polytetramethylene glycol (PTMG), polypropylene glycol (PPG), polycaprolactone diol (PCL) and polycarbonate diol (PCDL).

[0031] Based on the mass fraction of the polyol, the raw material for preparing the colorless and transparent polyurethane elastomer provided by the present invention preferably includes 30 to 158 parts of isocyanate, more preferably 50 to 130 parts, and more preferably 80 to 100 parts. In the present invention, the isocyanate includes alicyclic isocyanate and / or aliphatic isocyanate, and more preferably includes one or more of 4,4'-dicyclohexylmethane diisocyanate (HMDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI) and cyclohexane dimethylene diisocyanate (HXDI).

[0032] Based on the mass fraction of the polyol, the raw material for preparing the colorless and transparent polyurethane elastomer provided by the present invention preferably includes 20 to 88 parts of a chain extender, more preferably 30 to 70 parts, and more preferably 40 to 50 parts. In the present invention, the chain extender is tricyclo[5.2.1.0(2,6)]decanedimethanol, having a structure shown in Formula 1;

[0033]

[0034] Based on the mass fraction of the polyol, the raw material for preparing the colorless transparent polyurethane elastomer provided by the present invention preferably includes 0.2 to 4 parts of catalyst, more preferably 1 to 3 parts, and more preferably 1.5 to 2 parts. In the present invention, the catalyst preferably includes dibutyltin dilaurate (DBTDL).

[0035] The present invention also provides a method for preparing the colorless and transparent polyurethane elastomer described in the above technical solution, comprising the following steps:

[0036] Dehydrating the polyol to obtain a dehydrated polyol;

[0037] The dehydrated polyol, isocyanate and catalyst are mixed and prepolymerized to obtain a prepolymer;

[0038] The prepolymer and the chain extender are mixed, and then vulcanized and aged in sequence to obtain the colorless and transparent polyurethane elastomer.

[0039] The invention carries out dehydration treatment on the polyol to obtain dehydrated polyol.

[0040] In the present invention, the temperature of the dehydration treatment is preferably 110° C., and the time is preferably 2 hours; and the method of the dehydration treatment is preferably vacuum dehydration.

[0041] After the dehydration treatment, the present invention also preferably cools the dehydrated polyol, and the temperature after cooling is preferably consistent with the temperature of the subsequent prepolymerization.

[0042] After obtaining the dehydrated polyol, the present invention mixes the dehydrated polyol, isocyanate and a catalyst to perform prepolymerization to obtain a prepolymer.

[0043] In the present invention, the mixing process is preferably to add isocyanate and catalyst into the dehydrated polyol. In the present invention, the prepolymerization temperature is preferably 70-80°C, and the time is preferably 1-2 hours. In the present invention, the prepolymerization is preferably carried out under stirring.

[0044] After the prepolymerization, the present invention preferably does not carry out any post-treatment process, that is, directly carries out the subsequent reaction.

[0045] After obtaining the prepolymer, the present invention mixes the prepolymer and a chain extender, and sequentially performs vulcanization and aging to obtain the colorless and transparent polyurethane elastomer.

[0046] In the present invention, the chain extender is preferably preheated before the mixing, and the preheating temperature is preferably consistent with the temperature of the prepolymer.

[0047] After the mixing, the present invention also preferably includes subjecting the obtained mixed system to a centrifugal degassing treatment, and the time of the centrifugal degassing treatment is preferably 2 minutes.

[0048] In the present invention, the vulcanization method is preferably hot press vulcanization. In the present invention, the vulcanization temperature is preferably 80 to 120° C., and the time is preferably 2 to 5 hours. In the present invention, the vulcanization is preferably performed in a smooth mold.

[0049] After the vulcanization, the present invention also preferably includes demoulding the obtained material.

[0050] In the present invention, the aging temperature is preferably 50 to 80° C., and the aging time is preferably 12 to 24 hours. In the present invention, the aging is preferably carried out in an oven.

[0051] Unless otherwise specified, the materials and equipment used in the present invention are all commercially available products in the art.

[0052] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. 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.

[0053] Example 1

[0054] PTMG with a number average molecular weight of 1000 was vacuum dehydrated at 110°C for 2 h to obtain dehydrated PTMG;

[0055] 100 parts of dehydrated PTMG were added to the reactor, followed by 65.5 parts of HMDI and 0.2 parts of catalyst DBTDL, and the mixture was reacted at 80°C for 2 hours to obtain a prepolymer. Then, 27.9 parts of chain extender TDDM preheated at 80°C were added to the above-mentioned prepolymer at 80°C, and the mixture was degassed by centrifugation for 2 minutes. The mixture was poured into a smooth mold, hot-pressed and vulcanized in a vulcanizer at 80°C for 5 hours, and after demolding, the mixture was placed in a 50°C oven for aging for 12 hours to obtain a colorless and transparent polyurethane elastomer, which was recorded as PU1.

[0056] Example 2

[0057] PTMG with a number average molecular weight of 1000 was vacuum dehydrated at 110°C for 2 h to obtain dehydrated PTMG;

[0058] 100 parts of dehydrated PTMG were added to the reactor, followed by 76.0 parts of HMDI and 0.2 parts of catalyst DBTDL, and the mixture was reacted at 80°C for 2 hours to obtain a prepolymer. Then, 35.4 parts of chain extender TDDM preheated at 80°C were added to the prepolymer at 80°C, and the mixture was degassed by centrifugation for 2 minutes. The mixture was poured into a smooth mold and hot-pressed and vulcanized in a vulcanizer at 80°C for 5 hours. After demolding, the mixture was placed in a 50°C oven for aging for 12 hours to obtain a colorless and transparent polyurethane elastomer, which was recorded as PU2.

[0059] Example 3

[0060] PTMG with a number average molecular weight of 1000 was vacuum dehydrated at 110°C for 2 h to obtain dehydrated PTMG;

[0061] 100 parts of dehydrated PTMG were added to the reactor, followed by 86.5 parts of HMDI and 0.2 parts of catalyst DBTDL, and the mixture was reacted at 80°C for 2 hours to obtain a prepolymer. Then, 42.8 parts of chain extender TDDM preheated at 80°C were added to the prepolymer at 80°C, and the mixture was degassed by centrifugation for 2 minutes. The mixture was poured into a smooth mold and hot-pressed and vulcanized in a vulcanizer at 80°C for 5 hours. After demolding, the mixture was placed in a 50°C oven for aging for 12 hours to obtain a colorless and transparent polyurethane elastomer, which was recorded as PU3.

[0062] Example 4

[0063] PTMG with a number average molecular weight of 1000 was vacuum dehydrated at 110°C for 2 h to obtain dehydrated PTMG;

[0064] 100 parts of dehydrated PTMG were added to the reactor, followed by 64.4 parts of IPDI and 0.2 parts of catalyst DBTDL, and the mixture was reacted at 80°C for 2 hours to obtain a prepolymer. Then, 35.4 parts of chain extender TDDM preheated at 80°C were added to the prepolymer at 80°C, and the mixture was degassed by centrifugation for 2 minutes. The mixture was poured into a smooth mold and hot-pressed and vulcanized in a vulcanizer at 80°C for 5 hours. After demolding, the mixture was placed in a 50°C oven for aging for 12 hours to obtain a colorless and transparent polyurethane elastomer, which was recorded as PU4.

[0065] Comparative Example 1

[0066] PTMG with a number average molecular weight of 1000 was vacuum dehydrated at 110°C for 2 h to obtain dehydrated PTMG;

[0067] 100 parts of dehydrated PTMG were added to the reactor, followed by 76.0 parts of HMDI and 0.2 parts of catalyst DBTDL, and the mixture was reacted at 80°C for 2 hours to obtain a prepolymer. Then, 16.2 parts of chain extender 1,4-butanediol preheated at 80°C were added to the prepolymer at 80°C, and the mixture was centrifuged for degassing for 2 minutes. The mixture was poured into a smooth mold and hot-pressed and vulcanized in a vulcanizer at 80°C for 5 hours. After demolding, the mixture was placed in an oven at 50°C for aging for 12 hours to obtain a colorless and transparent polyurethane elastomer, which was recorded as PU0.

[0068] Performance Testing

[0069] The mechanical properties and hardness of the polyurethane elastomers obtained in Examples 1 to 4 and Comparative Example 1 were tested according to standards GB / T528-2009 and GB / 531.1-2008. The test results are shown in Table 1.

[0070] Table 1 Performance test results of polyurethane elastomers obtained in Examples and Comparative Examples

[0071] Sample name Tensile strength / MPa Elongation at break / % 100% modulus of elongation / MPa Hardness / HA Example 1 (PU1) 40.8 526.3 5.7 81 Example 2 (PU2) 43.4 368.4 12.5 95 Example 3 (PU3) 46.5 294.4 23.2 98 Embodiment 4 (PU4) 47.5 602.6 6.0 85 Comparative Example 1 (PU0) 10.3 1175.5 1.6 59

[0072] According to the standard GB / T2410-2008, the transmittance and haze were tested. The test results are shown in Table 2 and Figure 1 As shown;

[0073] Table 2 Transmittance and haze test results of polyurethane elastomers obtained in Examples and Comparative Examples

[0074]

[0075]

[0076] It can be seen from the above test results that the polyurethane elastomer provided by the present invention has excellent mechanical properties on the basis of being colorless and transparent.

[0077] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A colorless and transparent polyurethane elastomer, characterized in that: The raw materials for preparation are polyol, isocyanate, chain extender and catalyst; The polyol is polybutylene glycol; The isocyanate is 4,4'-dicyclohexylmethane diisocyanate or isophorone diisocyanate; The chain extender is tricyclo[5.2.1.0(2,6)]decanedimethanol, having the structure shown in Formula 1; The method for preparing the colorless and transparent polyurethane elastomer comprises the following steps: Dehydrating the polyol to obtain a dehydrated polyol; The dehydrated polyol, isocyanate and catalyst are mixed and prepolymerized to obtain a prepolymer; The prepolymer and the chain extender are mixed, and then vulcanized and aged in sequence to obtain the colorless and transparent polyurethane elastomer.

2. The colorless and transparent polyurethane elastomer according to claim 1, characterized in that: The raw materials for preparation include, by weight: 100 to 150 parts of polyol, 30 to 158 parts of isocyanate, 20 to 88 parts of chain extender and 0.2 to 4 parts of catalyst.

3. The colorless and transparent polyurethane elastomer according to claim 1 or 2, characterized in that: The number average molecular weight of the polyol is 1000-1500.

4. The colorless and transparent polyurethane elastomer according to claim 1 or 2, characterized in that: The catalyst includes dibutyltin dilaurate.

5. The method for preparing the colorless and transparent polyurethane elastomer according to any one of claims 1 to 4, characterized in that: The following steps are involved: Dehydrating the polyol to obtain a dehydrated polyol; The dehydrated polyol, isocyanate and catalyst are mixed and prepolymerized to obtain a prepolymer; The prepolymer and the chain extender are mixed, and then vulcanized and aged in sequence to obtain the colorless and transparent polyurethane elastomer.

6. The preparation method according to claim 5, characterized in that: The prepolymerization temperature is 70-80° C. and the prepolymerization time is 1-2 hours.

7. The preparation method according to claim 5, characterized in that: The vulcanization temperature is 80-120° C. and the vulcanization time is 2-5 hours.

8. The preparation method according to claim 5, characterized in that: The aging temperature is 50-80° C. and the aging time is 12-24 hours.

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