阅读说明：本技术 喷涂型聚氨酯弹性体组合物及其制备方法 (Spray-coating type polyurethane elastomer composition and preparation method thereof ) 是由 盖志科 房玉俊 段福运 韩胜奎 孟平 于 2021-08-19 设计创作，主要内容包括：本发明属于聚氨酯弹性体技术领域,具体涉及一种喷涂型聚氨酯弹性体组合物及其制备方法,所述弹性体组合物包括聚合物A组分和预聚物B组分,聚合物A组分由聚醚多元醇、固化剂、聚酯多元醇A、催化剂、抗氧剂和紫外线吸收剂制成；预聚物B组分NCO含量为12-28％,由聚酯多元醇B、异氰酸酯以及稀释剂制成。本发明通过在聚合物A组分以及预聚物B组分中采用不同种类的聚酯多元醇来提高聚氨酯弹性体的性能,其中A组分中芳香族聚酯多元醇可通过苯环的引入增强结构的刚性,在B组分中引入的聚酯多元醇中在结构中增加侧链的支化程度,提高其耐水解效果,保证产品具有较高力学性能的前提下,仍然具有较好的常温流动性和耐水解性能。(The invention belongs to the technical field of polyurethane elastomers, and particularly relates to a spray-coating polyurethane elastomer composition and a preparation method thereof, wherein the elastomer composition comprises a polymer A component and a prepolymer B component, wherein the polymer A component is prepared from polyether polyol, a curing agent, polyester polyol A, a catalyst, an antioxidant and an ultraviolet absorbent; the prepolymer B component has an NCO content of 12-28% and is prepared from polyester polyol B, isocyanate and a diluent. The invention improves the performance of the polyurethane elastomer by adopting different polyester polyols in the polymer A component and the prepolymer B component, wherein the aromatic polyester polyol in the A component can enhance the rigidity of the structure by introducing benzene rings, the branching degree of side chains is increased in the structure of the polyester polyol introduced in the B component, the hydrolysis resistance effect is improved, and the product still has better normal temperature fluidity and hydrolysis resistance on the premise of ensuring higher mechanical property.)

1. A spray-on polyurethane elastomer composition characterized by: comprising a polymer A component and a prepolymer B component, wherein:

the polymer A component is prepared from the following raw materials in parts by weight:

60-85 parts of polyether polyol, 10-30 parts of curing agent, 2-10 parts of polyester polyol A, 0.1-2 parts of catalyst, 0.2-2 parts of antioxidant and 0.2-2 parts of ultraviolet absorbent;

the prepolymer B component is an isocyanate-terminated polyurethane prepolymer, the content of isocyanate groups is 12-28%, and the prepolymer B component is prepared from the following raw materials in parts by weight:

15-35 parts of polyester polyol B, 50-80 parts of isocyanate and 5-20 parts of diluent.

2. The spray coated polyurethane elastomer composition of claim 1, wherein: in the component A, the molecular weight of the polyether polyol is 200-10000, and the polyether polyol is selected from one or more of ethylene oxide polyether polyol, propylene oxide polyether polyol, ethylene oxide and propylene oxide copolymerized polyether polyol or polytetrahydrofuran polyether polyol.

3. The spray coated polyurethane elastomer composition of claim 1, wherein: in the component A, the curing agent is one or more of diethyl toluenediamine, dimethyl-thio toluenediamine, N '-dialkyl methyldiphenylamine, 3' -dichloro-4, 4 '-diaminodiphenylmethane or 4,4' -methylene bis (3-chloro-2, 6-diethylaniline).

4. The spray coated polyurethane elastomer composition of claim 1, wherein: in the component A, the polyester polyol A is aromatic polyester polyol with the molecular weight of 200-1000, and is prepared by the ester exchange reaction of aromatic dicarboxylic acid and polyol.

5. The spray coated polyurethane elastomer composition of claim 1, wherein: in the component A, the catalyst is one or more of dibutyltin dilaurate, stannous octoate, bismuth isooctanoate, zinc isooctanoate, tetrabutyl titanate, tetraisopropyl titanate, trimethylene diamine, tetraethylenepentamine, N-methylmorpholine or N-methylimidazole.

6. The spray coated polyurethane elastomer composition of claim 1, wherein: in the component A, the antioxidant is selected from one or more of tetra [ beta- (3.5-di-tert-butyl, 4-hydroxyphenyl) propionic acid ] pentaerythritol ester alcohol, beta- (3.5-di-tert-butyl, 4-hydroxyphenyl) propionic acid octadecyl ester, 1,3, 5-tris (3, 5-di-tert-butyl-4-hydroxybenzyl) isocyanuric acid, tris (2.4-di-tert-butylphenyl) phosphite, bis (2, 4-di-tert-butylphenyl) pentaerythritol diphosphite, 3, 5-di-tert-butyl-4-hydroxyphenylpropionic acid isooctyl ester or 1-hydroxy-4-methyl-2, 6-bistertiary butylbenzene; the ultraviolet absorbent is one or more selected from phenyl o-hydroxybenzoate, 2- (2 '-hydroxy-5' -methylphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, resorcinol monobenzoate, 4-benzoyloxy-2, 2,6, 6-tetramethylpiperidine or hexamethylphosphoric triamide.

7. The spray coated polyurethane elastomer composition of claim 1, wherein: in the component B, the molecular weight of the polyester polyol B is 400-2000, the functionality is 2 or 3, and the polyester polyol B is selected from one or more of polyester polyol synthesized by ester exchange of micromolecular alcohol with a side chain and adipic acid, polycaprolactone polyol, polycarbonate polyol or dimer acid modified polyester polyol.

8. The spray coated polyurethane elastomer composition of claim 1, wherein: in the component B, the isocyanate is one or more of toluene diisocyanate, diphenylmethane diisocyanate, carbodiimide modified diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, 1, 5-naphthalene diisocyanate, p-phenylene diisocyanate, 1, 4-cyclohexane diisocyanate, xylylene diisocyanate, cyclohexanedimethylene diisocyanate, trimethyl-1, 6-hexamethylene diisocyanate or polymethylene polyphenyl polyisocyanate.

9. The spray coated polyurethane elastomer composition of claim 1, wherein: in the component B, the diluent is one or more of dibutyl phthalate, dioctyl phthalate, propylene carbonate, a mixture of ethylene carbonate and propylene carbonate, 2, 4-trimethyl-1, 3-pentanediol diisobutyrate, dimethyl carbonate or dimethoxy ethyl phthalate.

10. A process for the preparation of a spray-on polyurethane elastomer composition according to any one of claims 1 to 9, characterized in that: the method comprises the following steps:

(1) preparation of polymer a component:

adding a curing agent, polyether polyol, polyester polyol A, a catalyst, an antioxidant and an ultraviolet absorbent into a reaction kettle in proportion, dehydrating until the moisture content is less than 0.05%, and uniformly stirring to obtain a polymer A component;

(2) preparation of prepolymer B component:

adding polyester polyol B and a diluent into a reaction kettle, heating, vacuumizing and dehydrating until the moisture content is less than 0.05%, adding isocyanate for reaction until the content of isocyanate groups reaches a designed value, and cooling to obtain a prepolymer B component;

(3) when in use, the polymer A component and the prepolymer B component are uniformly mixed, sprayed on the surface of a sample, and cured to obtain the high-strength polyurethane elastomer.

Technical Field

The invention belongs to the technical field of polyurethane elastomers, and particularly relates to a spray-coating polyurethane elastomer composition and a preparation method thereof.

Background

The polyurethane elastomer is a block copolymer composed of a soft segment and a hard segment, has the high elasticity of rubber and the rigidity of plastic, and has excellent wear resistance, high bearing capacity, high tearing strength, low temperature resistance, oil resistance, ozone resistance and other properties. The polyurethane elastomer sprayed on the surface of the material can play an excellent wear-resistant and corrosion-resistant role, so that the material can be applied in a relatively harsh environment, and the longer protection period than that of the conventional wear-resistant and corrosion-resistant coating is realized. The spray polyurethane elastomer is widely applied to industries such as mines, ports, automation, sewage treatment, chemical engineering and the like, plays an increasingly important role in the industry of wear-resistant and corrosion-resistant materials, and has a very wide development prospect.

In the conventional spray coating type polyurethane elastomer preparation technology, polyether polyol and isocyanate component are generally adopted to react to prepare prepolymer, and polyether polyol and curing agent are mainly adopted in the polymer component. For example, patent CN201410342649.1 discloses an elastomer composition for polyurethane spray coating and a preparation method thereof, comprising a polymer component and a prepolymer component, wherein the polymer component is composed of propylene oxide polyether polyol, a curing agent, a catalyst, an antioxidant, an ultraviolet absorbent and a defoaming agent, and the prepolymer component is prepared from aromatic isocyanate and polyether polyol. The spraying type polyurethane elastomer prepared by adopting polyether polyol has lower mechanical property, and simultaneously, along with the continuous expansion of the application field of the spraying type polyurethane elastomer in wear-resistant anticorrosive materials, higher requirements are provided for the performance of the spraying material.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the spraying type polyurethane elastomer composition overcomes the defects of the prior art, improves the mechanical property of the spraying type polyurethane elastomer, has small product viscosity, good fluidity, no crystallization at normal temperature, normal-temperature operation, quick curing time, excellent mechanical property, good adhesive property and wear resistance, and can stably protect the sprayed object for a long time; the invention also provides a preparation method of the composition.

The invention is realized by adopting the following technical scheme:

the spray type polyurethane elastomer composition comprises a polymer A component and a prepolymer B component, wherein:

the polymer A component is prepared from the following raw materials in parts by weight:

60-85 parts of polyether polyol, 10-30 parts of curing agent, 2-10 parts of polyester polyol A, 0.1-2 parts of catalyst, 0.2-2 parts of antioxidant and 0.2-2 parts of ultraviolet absorbent;

the prepolymer B component is an isocyanate-terminated polyurethane prepolymer, the content of isocyanate group (NCO-) is 12-28%, preferably 15-20%, and the prepolymer B component is prepared from the following raw materials in parts by weight:

15-35 parts of polyester polyol B, 50-80 parts of isocyanate and 5-20 parts of diluent.

In the component A, the polyether polyol has a molecular weight of 200-10000, preferably 1000-5000, and is selected from one or more of ethylene oxide polyether polyol, propylene oxide polyether polyol, ethylene oxide-propylene oxide copolymerized polyether polyol or polytetrahydrofuran polyether polyol.

In the component A, the curing agent is one or more of diethyl toluenediamine, dimethyl-thio toluenediamine, N '-dialkyl methyldiphenylamine, 3' -dichloro-4, 4 '-diaminodiphenylmethane or 4,4' -methylene bis (3-chloro-2, 6-diethylaniline).

In the component A, the polyester polyol A is aromatic polyester polyol with the molecular weight of 200-1000, and is prepared by the ester exchange reaction of aromatic dicarboxylic acid and polyol.

In the component A, the catalyst is one or more of dibutyltin dilaurate, stannous octoate, bismuth isooctanoate, zinc isooctanoate, tetrabutyl titanate, tetraisopropyl titanate, trimethylene diamine, tetraethylenepentamine, N-methylmorpholine or N-methylimidazole.

In the component A, the antioxidant is selected from one or more of pentaerythritol tetra [ beta- (3.5-di-tert-butyl, 4-hydroxyphenyl) propionate ] pentaerythritol ester alcohol, octadecyl beta- (3.5-di-tert-butyl, 4-hydroxyphenyl) propionate, 1,3, 5-tris (3, 5-di-tert-butyl-4-hydroxybenzyl) isocyanuric acid, tris (2.4-di-tert-butylphenyl) phosphite, bis (2, 4-di-tert-butylphenyl) pentaerythritol diphosphite, isooctyl 3, 5-di-tert-butyl-4-hydroxyphenylpropionate or 1-hydroxy-4-methyl-2, 6-bistributylbenzene.

In the component A, the ultraviolet absorbent is selected from one or more of phenyl o-hydroxybenzoate, 2- (2 '-hydroxy-5' -methylphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, resorcinol monobenzoate, 4-benzoyloxy-2, 2,6, 6-tetramethylpiperidine or hexamethylphosphoric triamide.

In the component B, the molecular weight of the polyester polyol B is 400-2000, the functionality is 2 or 3, and the polyester polyol B is selected from one or more of polyester polyol synthesized by ester exchange of micromolecular alcohol with a side chain and adipic acid, polycaprolactone polyol, polycarbonate polyol or dimer acid modified polyester polyol.

In the component B, the isocyanate is one or more of toluene diisocyanate, diphenylmethane diisocyanate, carbodiimide modified diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, 1, 5-naphthalene diisocyanate, p-phenylene diisocyanate, 1, 4-cyclohexane diisocyanate, xylylene diisocyanate, cyclohexanedimethylene diisocyanate, trimethyl-1, 6-hexamethylene diisocyanate or polymethylene polyphenyl polyisocyanate.

In the component B, the diluent is one or more of dibutyl phthalate, dioctyl phthalate, propylene carbonate, ethylene carbonate, 2, 4-trimethyl-1, 3-pentanediol diisobutyrate, dimethyl carbonate or dimethoxy ethyl phthalate.

The preparation method of the spray type polyurethane elastomer composition comprises the following steps:

(1) preparation of polymer a component:

adding a curing agent, polyether polyol, polyester polyol A, a catalyst, an antioxidant and an ultraviolet absorbent into a reaction kettle in proportion, dehydrating until the moisture content is less than 0.05%, and uniformly stirring to obtain a polymer A component;

(2) preparation of prepolymer B component:

adding polyester polyol B and a diluent into a reaction kettle, heating to 90-100 ℃, vacuumizing and dehydrating until the moisture content is less than 0.05%, cooling to 50-60 ℃, adding isocyanate to react at 70-80 ℃ for 2-3h until the content of isocyanate (NCO-) reaches a design value, cooling and cooling to obtain a prepolymer B component;

(3) when in use, the polymer A component and the prepolymer B component are sprayed on the surface of a sample at the temperature of 50-60 ℃ according to the volume ratio of 1:1, and the polyurethane elastomer with high strength can be obtained after standing and curing at normal temperature.

Compared with the prior art, the invention has the following beneficial effects:

1. the invention improves the performance of the polyurethane elastomer by adopting different polyester polyols in the polymer A component and the prepolymer B component, wherein the aromatic polyester polyol in the A component can enhance the rigidity of the structure by introducing benzene rings, the branching degree of side chains is increased in the structure of the polyester polyol introduced in the B component, the hydrolysis resistance effect is improved, and the product still has better normal temperature fluidity and hydrolysis resistance on the premise of ensuring higher mechanical property.

2. The spray type polyurethane elastomer composition provided by the invention has small viscosity at normal temperature and good fluidity, and can be operated at normal temperature.

3. The spraying type polyurethane elastomer provided by the invention has good mechanical property, the tensile strength can reach 32MPa, the elongation at break is between 390 and 460 percent, and the balance between the strength and the flexibility is realized.

Detailed Description

The present invention will be described in detail and specifically with reference to the following examples to facilitate better understanding of the present invention, but the following examples do not limit the scope of the present invention.

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods. Wherein:

EP-330N, polyether polyol having a number average molecular weight of 5000 and a functionality of 3, Dow chemical industries, Inc., Dow of Shandong Lanxingdong;

DL-2000, a polyether polyol having a number average molecular weight of 2000 and a functionality of 2, Shandong Lanxingdong chemical industries, Inc.;

e-100, diethyltoluenediamine, Yabao, USA;

MOCA, 3,3 '-dichloro-4, 4' -diaminodiphenylmethane, sco xiang garden new materials gmbh;

PE-D503, an aromatic polyester polyol having a number average molecular weight of 380 and a functionality of 2, available from Norway polyurethane, Shandong, Inc.;

DJ210, polycaprolactone polyol having a number average molecular weight of 1000 and a functionality of 2, manufactured by nippon xylonite chemical industries;

PE-7010, polyester polyol synthesized by ester exchange with neopentyl glycol and adipic acid as monomers and having a number average molecular weight of 1000 and a functionality of 2, Shandong-Nowei polyurethane Ltd;

DA-20, dimer acid-modified polyester polyol having a number average molecular weight of 1000 and a functionality of 2, Shanghai Jing Nissan New materials science and technology Co., Ltd;

mixtures of MDI-50, 2, 4-diphenylmethane diisocyanate and 4,4' -diphenylmethane diisocyanate, Vanhua chemical group Ltd;

MDI-100HL, carbodiimide modified MDI, Wanhua chemical group Ltd;

TXIB, 2,2, 4-trimethyl-1, 3-pentanediol diisobutyrate, Istmann chemical Co., USA;

antioxidant 1010, tetrakis [ beta- (3, 5-di-tert-butyl, 4-hydroxyphenyl) propanoic acid ] pentaerythritol esterol, yabao corporation, usa;

antioxidant 10076, octadecyl beta- (3, 5-di-tert-butyl, 4-hydroxyphenyl) propionate, yabazao, usa;

antioxidant BHT, 1-hydroxy-4-methyl-2, 6-ditertiary butylbenzene, Germany, Langshen chemical Co., Ltd;

antioxidant 626, bis (2, 4-di-t-butylphenyl) pentaerythritol diphosphite, Hubei Jusheng science and technology, Inc.;

UV-9, 2-hydroxy-4-methoxybenzophenone, Beijing carbofuran technologies, Inc.;

UV-P, 2- (2 '-hydroxy-5' -methylphenyl) benzotriazole, beijing carbofuran technologies ltd.

Example 1

The polyurethane type spray elastomer was prepared as follows:

(1) preparation of polymer a component:

adding 28 parts of E-100, 5 parts of PE-D503, 22 parts of EP-330N, 43.5 parts of DL-2000, 0.5 part of bismuth isooctanoate catalyst, 0.3 part of antioxidant 1010, 0.2 part of antioxidant 626 and 0.5 part of UV-9 into a reaction kettle according to a proportion, dehydrating until the water content is less than 0.05 percent, and uniformly stirring to obtain the component A of the polymer.

(2) Preparation of prepolymer B component

Adding 30 parts of DJ210 and 10 parts of TXIB into a reaction kettle, heating to 90 ℃, vacuumizing and dehydrating until the moisture content is less than 0.05%, cooling to 50 ℃, adding 60 parts of MDI-50 for reaction, reacting at 75 ℃ until the NCO content reaches 17.5% of a designed value, cooling, and independently packaging the materials to obtain the prepolymer B component.

(3) When the spraying type polyurethane elastomer is used, the polymer A component and the prepolymer B component are sprayed at the temperature of 55 ℃ according to the volume ratio of 1:1 to prepare a sample, and the sample is placed at normal temperature for curing to obtain the spraying type polyurethane elastomer.

Example 2

The polyurethane type spray elastomer was prepared as follows:

(1) preparation of polymer a component:

adding 28 parts of E-100, 5 parts of PE-D503, 65 parts of EP-330N, 0.5 part of dibutyltin dilaurate catalyst, 0.3 part of antioxidant 1010, 0.2 part of antioxidant 626 and 1 part of UV-9 into a reaction kettle in proportion, dehydrating until the water content is less than 0.05%, and uniformly stirring to obtain the component A of the polymer.

(2) Preparation of prepolymer B component

Adding 30 parts of DA20 and 10 parts of TXIB into a reaction kettle, heating to 90 ℃, vacuumizing and dehydrating until the moisture content is less than 0.05%, cooling to 60 ℃, adding 50 parts of MDI-50 and 10 parts of MDI-100HL for reaction, reacting at 75 ℃ until the NCO content reaches 17% of the design value, cooling, and independently packaging the materials to obtain the prepolymer B component.

(3) When the spraying type polyurethane elastomer is used, the polymer A component and the prepolymer B component are sprayed at the temperature of 55 ℃ according to the volume ratio of 1:1 to prepare a sample, and the sample is placed at normal temperature for curing to obtain the spraying type polyurethane elastomer.

Example 3

The polyurethane type spray elastomer was prepared as follows:

(1) preparation of polymer a component:

adding 15 parts of E-100, 12 parts of MOCA, 10 parts of PE-D503, 61 parts of EP-330N, 0.5 part of bismuth isooctanoate catalyst, 0.3 part of antioxidant 1076, 0.2 part of antioxidant BHT and 1 part of UV-9 into a reaction kettle in proportion, dehydrating until the water content is less than 0.05%, and uniformly stirring to obtain the component A of the polymer.

(2) Preparation of prepolymer B component

Adding 30 parts of PE-7010 and 15 parts of TXIB into a reaction kettle, heating to 100 ℃, vacuumizing and dehydrating until the moisture content is less than 0.05%, cooling to 60 ℃, adding 50 parts of MDI-50 and 5 parts of MDI-100HL for reaction, reacting at 70 ℃ until the NCO content reaches the designed value of 15.5%, cooling, and independently packaging the materials to obtain the prepolymer B component.

(3) When the spraying type polyurethane elastomer is used, the polymer A component and the prepolymer B component are sprayed at the temperature of 60 ℃ according to the volume ratio of 1:1 to prepare a sample, and the sample is placed at normal temperature for curing to obtain the spraying type polyurethane elastomer.

Example 4

The polyurethane type spray elastomer was prepared as follows:

(1) preparation of polymer a component:

adding 26 parts of E-100, 8 parts of PE-D503, 64 parts of EP-330N, 0.5 part of bismuth isooctanoate catalyst, 0.3 part of antioxidant 1010, 0.2 part of antioxidant 626, 0.5 part of UV-9 and 0.5 part of UV-P into a reaction kettle according to a proportion, dehydrating until the water content is less than 0.05 percent, and uniformly stirring to obtain the component A of the polymer.

(2) Preparation of prepolymer B component

Adding 30 parts of PE-7010 and 15 parts of TXIB into a reaction kettle, heating to 95 ℃, vacuumizing and dehydrating until the moisture content is less than 0.05%, cooling to 55 ℃, adding 50 parts of MDI-50 and 5 parts of MDI-100HL for reaction, reacting at 80 ℃ until the NCO content reaches the designed value of 15.5%, cooling, and independently packaging the materials to obtain the prepolymer B component.

(3) When the spraying type polyurethane elastomer is used, the polymer A component and the prepolymer B component are sprayed at 50 ℃ according to the volume ratio of 1:1 to prepare a sample, and the sample is placed at normal temperature for curing to obtain the spraying type polyurethane elastomer.

Comparative example 1

The polyurethane type spray elastomer was prepared as follows:

(1) preparation of polymer a component:

adding 30 parts of E-100, 58 parts of EP-330N, 10 parts of DL-2000, 0.5 part of bismuth isooctanoate catalyst, 0.3 part of antioxidant 1076, 0.2 part of antioxidant BHT and 1 part of UV-9 into a reaction kettle in proportion, dehydrating until the water content is less than 0.05%, and uniformly stirring to obtain the component A of the polymer.

(2) Preparation of prepolymer B component

Heating 47 parts of DL2000 to 90 ℃, carrying out vacuum-pumping dehydration until the moisture content is less than 0.05%, cooling to 55 ℃, adding 53 parts of MDI-50 for reaction, reacting at 75 ℃ until the NCO content reaches 15.5% of the design value, cooling, and independently packaging the materials to obtain the prepolymer B component.

(3) When the spraying type polyurethane elastomer is used, the polymer A component and the prepolymer B component are sprayed at the temperature of 50 ℃ according to the volume ratio of 1:1 to prepare a sample, and the sample is placed at normal temperature for curing to obtain the spraying type polyurethane elastomer.

The polyurethane elastomers prepared in examples 1 to 4 and comparative example 1 were subjected to performance tests, tensile strength, elongation at break, stress at definite elongation, tear strength: tested according to GB/T529-2009. The test results are shown in table 1.

TABLE 1 mechanical Properties of the elastomers of examples 1-4 and comparative example 1

Item	Example 1	Example 2	Example 3	Example 4	Comparative example 1
						Gel time, s	7	7	27	7	6
Tensile strength, MPa	32	29	29	27	17.2
						Elongation at break,%	458	390	410	429	488
100% stress at definite elongation, MPa	12.1	11.8	12.2	10.4	7.8
						300% stress at definite elongation, MPa	23.6	26.3	25.9	21.1	12.7
Right angle tear strength, KN/m	71	71	72	69	56

The results in table 1 show that the mechanical properties of the spray-coating polyurethane elastomer prepared by the method are significantly higher than those of the conventional technical scheme, because the addition of the polyester polyol can enhance the polarity of molecular chain segments and enhance intermolecular forces, the mechanical properties of the material can be effectively improved, and meanwhile, the selection and formula design of the polyester polyol can realize that the composition is in a low-viscosity liquid state at normal temperature, thereby ensuring the normal operation of the spray-coating process.

The polyurethane elastomers of the polyester polyol system are susceptible to hydrolysis reaction compared to the polyether system, and table 2 compares the mechanical properties of the polyurethane elastomer sample sheets prepared in examples 1-4 and comparative example 1 after hydrolysis test. The hydrolysis condition is that the sample piece is soaked in water with the temperature of 70 ℃ for one week. The hydrolysis resistance of the material can be judged by comparing the mechanical properties before and after hydrolysis. The data show that the spraying type polyurethane elastomer prepared by the technical scheme has excellent hydrolysis resistance. The performance is reduced after hydrolysis, but is still higher than the conventional technical scheme.

TABLE 2 data of performance tests after hydrolysis at elevated temperature for examples 1-4 and comparative example 1

Item	Example 1	Example 2	Example 3	Example 4	Comparative example 1
						Tensile strength, MPa	22.4	28	21.2	20.4	12.9
Elongation at break,%	408	436	394	403	439
						100% stress at definite elongation, MPa	8.9	11.6	9.4	9.2	6.6
300% stress at definite elongation, MPa	16.8	25.9	18.6	16.8	9.9
						Right angle tear strength, KN/m	61	72	64	61	50

Of course, the foregoing is only a preferred embodiment of the invention and should not be taken as limiting the scope of the embodiments of the invention. The present invention is not limited to the above examples, and equivalent changes and modifications made by those skilled in the art within the spirit and scope of the present invention should be construed as being included in the scope of the present invention.