CN114763433A

CN114763433A - Low-density polyurethane microporous foam composition and application thereof

Info

Publication number: CN114763433A
Application number: CN202110046190.0A
Authority: CN
Inventors: 韩艳; 王晓星; 王玉领
Original assignee: Wanhua Chemical Beijing Co Ltd
Current assignee: Wanhua Chemical Beijing Co Ltd
Priority date: 2021-01-14
Filing date: 2021-01-14
Publication date: 2022-07-19

Abstract

The invention relates to a composition of a microporous polyurethane moulding, consisting of (a) an organic polyisocyanate; (b) at least twoA compound having a reactive hydrogen atom; (c) a gas phase dioxide or a combination thereof as a cell opener; (d) a glycol chain extender; (e) a crosslinking agent, and other additional components of (f) - (h). Polyurethane prepared from the above components 250-400kg/m³The low-density molded body of (2) has improved physical properties, and solves the problems of easy shrinkage deformation and surface bubbles of the low-density molded body, and improves the stability of the same type of molded body. The molded article of the present invention can be used as a material for shoe soles, elastomers, and the like.

Description

Low-density polyurethane microporous foam composition and application thereof

Technical Field

The invention relates to a low-density polyurethane microporous foam composition and application thereof as a sole.

Background

Polyurethane as sole foam, has soft hand feeling and is easy to wearThe sole material has the advantages of comfort, warmth retention, high elasticity and skid resistance, is simple to machine and form, and has excellent wear resistance, fatigue resistance and low damping compared with other common sole materials; however, it is difficult to obtain a molded body of a polyurethane molded body having a lower density, particularly a density of less than 350kg/m, in order to satisfy the requirement of lightening the sole³And simultaneously has a foam material meeting the requirements of the process and the use, and limits the further application of the polyurethane as a sole material.

It is known that when a polyurethane foam having a density lower than the normal density is produced, problems such as foam retraction, dimensional instability, low springback, and a decrease in bending resistance tend to occur. Therefore, in order to satisfy the demands for lightweight soles and reduction in raw material costs, the development of preparing low-density microcellular foams having good open-cell structures, dimensional stability, and simultaneously good physical properties has been one of the development directions of polyurethane sole materials in recent years.

In order to obtain polyurethane foams which have no surface shrinkage, good properties and are dimensionally stable and can be used as shoe soles, some documents describe possible solutions or processes for improving the properties of low-density foams. For example: in order to improve the dimensional stability of the low-density foam and enable the low-density foam to have lower compression deformation, CN201180064990 utilizes a mode of adding cell opening agents based on ethylhexyl acrylate, polybutadiene, polyisobutylene, organosiloxane and the like to increase the open cells of the low-density microcellular foam and prepare the dimensionally stable low-density foam; the problem with this process for preparing foams is that relatively large amounts need to be added to achieve the effect of increasing the open cells and often leads to cell coarsening or, in turn, to a considerable influence on some of the mechanical properties of the polyurethane moldings. CN201080056052 utilizes a polyether-polyesterol system to prepare a dimensionally stable polyurethane microcellular foam, which has the disadvantages that the incompatibility of two polyol systems of polyether and polyester needs to be compensated by a specific suitable silicone oil surfactant, and the compatibility problem of the system also causes the loss of the foam physical properties, such as resilience, and is not favorable for the low-density foam applicability. CN201380006096.6 utilizes glycerin and grafted polyether to prepare low-density sole foam with low compression deformation, and although the method can ensure the strength performance of the low-density foam, the bending resistance of the foam is reduced due to the crosslinking point and the soft segment with increased hardness; CN10266625B selects to add plasticizers such as propylene carbonate and acetyl tri-n-butyl citrate to improve the low-temperature bending resistance of low-density foam, and particularly the low-temperature flexibility of the foam when the low-density foam is used in polyester polyurethane safety shoe soles, but the method has the problems that the use of the plasticizers is selective, the plasticizers with specific solvation effect need to be selected, otherwise the application of the plasticizers in other polyurethane shoe sole systems is limited, and the physical property performance is generally reduced.

The method for preparing the low-density polyurethane foam improves the surface retraction, compression deformation or flexing resistance lost due to the reduction of material density by increasing the open pores, matching polyether and polyester, increasing the branching crosslinking or introducing the plasticizer, but has the common problem that the newly introduced raw materials cause the reduction of the performance of one or more aspects of the molded foam to different degrees due to chemical composition or structural factors, thereby causing the limitation of practical application.

Disclosure of Invention

The invention aims to provide a low-density polyurethane microcellular foam which has no shrinkage, good physical properties and meets the folding resistance, and the density of the low-density polyurethane microcellular foam is 350kg/m³It can be used as polyurethane type sole material.

In order to achieve the above purpose, the invention adopts the following scheme:

the invention firstly provides a low-density microcellular polyurethane foam, which comprises the following raw materials in parts by weight:

(a) 30-150 parts of polyisocyanate (such as 50, 60, 70, 80, 90, 110, 130 and the like)

(b) 100 parts of a compound having at least two hydrogen atoms reactive toward isocyanates

(c) 0.02-5 parts of cell opener (such as 0.1, 0.5, 1,2, 3, 4, etc.)

(d) Chain extenders 1-25 parts (e.g., 2, 5, 8, 10, 12, 15, 20, etc.)

(e) 0-10 parts of crosslinking agent (e.g., 0, 1,2, 4, 8, etc.)

(f) Catalyst 0.5-5 parts (e.g. 1,2, 3, 4, etc.)

(g) 0.1-3 parts of emulsified silicone oil (e.g. 0.5, 1,2, 3, etc.)

(h) 0-10 parts (e.g., 0, 2, 3, 5, etc.) of other adjuvants and/or additives.

In the polyurethane foam of the present invention, the (a) polyisocyanate is selected from aliphatic, alicyclic and aromatic di-or polyfunctional isocyanates, preferably 4, 4' -MDI is used, and the (a) polyisocyanate may contain 0 to 20% by weight of carbodiimide or uretonimine modified polyisocyanate.

In the polyurethane foam of the present invention, the (b) compound having at least two hydrogen atoms reactive with isocyanate includes (b1) and (b2), and the weight ratio of (b1) to (b2) is (0.5 to 20): 1, preferably (1-15): 1;

wherein (b1) is a polyether polyol having primary OH groups, a molecular weight of 4000-8000g/mol and a functionality of 2-4. (b2) Is one or more of polytetrahydrofuran polyol, polycaprolactone polyol and polycaprolactone-initiated polypropylene oxide polyol, preferably, the molecular weight of the polytetrahydrofuran polyol is 1000-3000g/mol, the functionality is 2-3, and the molecular weight of the polycaprolactone polyol or polycaprolactone-initiated polypropylene oxide polyol is 1000-3000g/mol, the functionality is 2-4. (b1) And (b2) respectively participating in the reaction of isocyanate to form a polyurethane foam backbone;

preferably, the polyether polyol of primary OH groups (b1) used is a polyoxypropylene-polyoxyethylene block copolyol having a polyoxyethylene polyol block content of 15-30%, a molecular weight of 5000-8000g/mol, more preferably of 6000-8000g/mol, and a functionality of 2-3; or a polymer-grafted polyether polyol, typically a polystyrene-acrylonitrile polymer-grafted polyoxypropylene polyol having a content of 20-40% by weight. Higher polyether molecular weights contribute to improved foam flex resistance and resilience;

preferably, the (b2) used is a polytetrahydrofuran polyether, preferably having a molecular weight of 1000-2500g/mol, a functionality of 2-3, and/or a polycaprolactone polyol, preferably having a functionality of 2-3. The use of polytetrahydrofuran polyether is beneficial to improving the physical property and strength of the foam; the molecular weight of the polycaprolactone polyol has the characteristics of soft chain segment, high extensibility and low Tg, and the polycaprolactone polyol has good compatibility with a polypropylene oxide-ethylene oxide polyether system. In the preparation of low-density foam, compared with polypropylene oxide polyol, the polytetrahydrofuran polyether and polycaprolactone polyol have more linear and regular structures and narrower molecular weight distribution, so that the improvement of the elasticity, physical properties and dimensional stability of the foam is more remarkable, and the mixing use of the two polyols can enable the comprehensive performance of the foam to reach the optimal balance.

In the polyurethane foam of the present invention, the cell opening agent (c) contains a hydrophobically modified fumed silica. Preferably, the pore-opening agent is a composition formed by mixing hydrophobic modified fumed silica, a silane coupling agent and nonpolar alkane in a ratio of (1) (0.1-0.5) to (1-5) (weight ratio);

wherein the silane coupling agent can be 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, methyltrimethoxysilane, n-octyltrimethoxysilane, etc.;

the nonpolar alkane can be liquid polybutadiene, liquid polyisobutene, liquid polyisoprene and the like, and the molecular weight is preferably 500-3000 g/mol;

among other things, the hydrophobically modified fumed silica functions to increase the open cells of polyurethane molded bodies, improve the problem of foam shrinkage, while not affecting the overall structure of the cells, including not increasing coarse cells, and not affecting the physical support structure of the foam, thereby maintaining the mechanical properties of the foam. The hydrophobic modified fumed silica can be modified by bonding different modifying groups on the surface, and the modifying groups can be hydrophobic groups, such as hexamethylsilazane, dimethyldichlorosilane, octylsilane, hexadecylsilane and the like. Hydrophobic modified fumed silica specific surface area of 100-500m²Per g, preferably 200-350m²A carbon content of 1 to 10 wt.%, preferably 2 to 6 wt.%, and an average primary particle diameter of 2 to 20nm, preferably 5 to 10 nm. The hydrophobically modified fumed silica commercial product can be the winning Aerosil series fumed silicaSilicon compounds, e.g.

R805, R974, R972, R812S, R816, and the like. In addition, as a preferable scheme of the pore-forming agent, a composition prepared by mixing the hydrophobic modified fumed silica, the silane coupling agent and the nonpolar alkane in a ratio of 1 (0.1-0.5) to (1-5) is used, and the composition is unexpectedly found to have more excellent effects, namely more excellent pore-forming effect and system stability;

since fumed silica is a fine particle, in order to reduce the operation difficulty, in practical use, a corresponding type of commercial grade high-concentration silicon paste product or a suspension thereof in silicone oil can be selected for convenient addition. Meanwhile, due to the nanometer inorganic particles and the surface activity characteristics of the fumed silica, the use of the fumed silica and the silicon paste or suspension liquid matched with the fumed silica can improve the wear resistance of the foam; the existence of silicon hydroxyl on the surface of the hydrophobic modified fumed silica can increase hydrogen bonds between the polyether and isocyanate molecules of reactants, thereby improving the viscosity of the composition and reducing the layering of the system. On the other hand, as the polytetrahydrofuran polyether and the polycaprolactone polyol have stronger intermolecular cohesion, the foam containing the two raw materials shows the obvious change of the foam hardness along with the temperature while obviously improving the physical properties of the low-density foam, which is obviously avoided in the aspect of application stability of the foam. The scheme unexpectedly discovers that due to the existence of certain silicon hydroxyl and surface modification groups in the solution of fumed silica or dimethyl siloxane thereof, the orderly regularity of intermolecular acting force of a system polymer is reduced to a certain extent, so that the crystallinity of polytetrahydrofuran polyether and polycaprolactone polyol serving as a foam soft segment is reduced, and the negative influence of the polytetrahydrofuran polyether and polycaprolactone polyol on the hardness of low-density foam is reduced.

In the polyurethane foam of the present invention, as the chain extender (d), a molecular weight of preferably 50 to 300g/mol, it is preferable to use a C-alkanediol having 2 to 12 carbon atoms, a dialkylene glycol having 4 to 8 carbon atoms, an alkanoolamine having 2 to 12 carbon atoms, such C-alkanediols having 2 to 12 carbon atoms as ethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 1, 7-heptanediol, 1, 8-octanediol, 1, 9-nonanediol, 1, 10-decanediol, preferably ethylene glycol, 1, 4-butanediol, a dialkylene glycol having 4 to 8 carbon atoms, preferably diethylene glycol and dipropylene glycol, an alkanoolamine having 2 to 12 carbon atoms, ethanolamine, 2-aminopropanol are preferred.

In the polyurethane foam of the present invention, the crosslinking agent (e) is preferably selected from trifunctional or higher alcohols such as glycerin, trimethylolpropane, pentaerythritol and trihydroxycyclohexane, and trialkanolamines such as triethanolamine.

In the polyurethane foam of the present invention, the catalyst (f) is preferably a tertiary amine, tertiary amine salt/quaternary amine salt, organic metal compound, optionally a tertiary amine such as tetramethylethylenediamine, N-methylmorpholine, 1-methylimidazole, 1, 2-dimethylimidazole, diethylbenzylamine, triethylamine, dimethylcyclohexylamine, diazabicyclooctane, N, N ' -dimethylpiperazine, N methyl, N ' - (4-N-dimethylamino) butylpiperazine, N, N, N ', N "-pentamethyldiethylenediamine, preferably 1, 4-diazabicyclo [2.2.2] octane, pentamethyldiethylenetriamine or the like; the tertiary/quaternary amine salts may be formed by reacting the above-mentioned tertiary amines with organic acids (e.g., formic acid, hydrochloric acid, lactic acid, citric acid); organometallic compounds, for example tin (II) salts or bismuth salts of organic carboxylic acids, preferably tin (II) dioctoate, tin (II) dilaurate, dibutyltin diacetate or dibutyltin dilaurate, bismuth (III) neodecanoate, bismuth 2-ethylhexanoate, bismuth octoate and the like.

The emulsified silicone oil (g) is modified polysiloxane, preferably polyether modified siloxane, further preferably epoxypropylene polyether modified polysiloxane, and the commercially available grades can be selected from the winning grades

B8002、

DC3043 with the aim of achieving a proper balance of emulsification and foam homogenization in low density foam systemsAnd helps to obtain a foam system with a superior combination of cell morphologies.

The polyurethane foams of the present invention may also contain (h) other auxiliary agents/additives such as blowing agents (e.g., water), antistatic agents, anti-wear agents, flame retardants, inorganic fillers, and the like, optionally in amounts of 0-10% by weight of component (b), depending on the desired properties of the foam.

In a second aspect of the invention, there is provided a process for the preparation of the polyurethane foams described above by introducing a defined amount of reaction mixture into a mold to give the desired design of the density of the molding, in particular of the overall foam, preferably 100-450kg/m³More preferably 200-400kg/m³Particularly preferably 250-350kg/m³。

For example, in one embodiment, the method of preparation may comprise the steps of:

(1) the polyisocyanate (a) is used alone as the A component;

(2) uniformly mixing the compound (B) with at least two hydrogen atoms which are reactive to isocyanate, a cell opening agent (c), a chain extender (d), a cross-linking agent (e), a catalyst (f), emulsified silicone oil (g), other auxiliary agents and/or additives (h) to form a component B;

(3) introducing the A component and the B component into a mold at a temperature of 15-90 ℃, preferably 25-55 ℃, and injecting the mixture into the mold by a stirrer or a spiral mixer under normal pressure or high pressure;

in the preparation method, the temperature of the die is set to be 20-160 ℃, preferably 30-120 ℃, and particularly preferably 30-60 ℃; after the molded product is taken out of the mold, the temperature is kept at room temperature to 120 ℃ until the curing is completed, and the curing time is 0 to 7 days, preferably 1 to 3 days.

In another embodiment, the preparation method may comprise the steps of:

(1) reacting the polyisocyanate (a) with polyol (b1) or (b2), optional chain extender (d) and optional cross-linking agent (e) to obtain prepolymer, namely A component; the prepolymer may be prepared by reaction at a temperature of from 30 to 100 deg.C, preferably at about 80 deg.C, for a period of from 1 to 5 hours, preferably from 1 to 3 hours;

(2) uniformly mixing the rest of the component (B), the pore-forming agent (c), the rest of the chain extender (d), the rest of the cross-linking agent (e), the catalyst (f), the emulsified silicone oil (g) and other additives and/or additives (h) to form a component B;

(3) the A-component and B-component are introduced into the mold at a temperature of 15 to 90 deg.C, preferably 25 to 55 deg.C, and the mixing process can be mechanically injected into the mold under normal pressure or high pressure by means of a stirrer or a screw mixer.

The preparation is conventional in the art, and preferably, the a component is in the form of a prepolymer.

The polyurethane foams prepared in accordance with the invention preferably have a viscosity of 250-350kg/m³The average density of (b) can be used as a material for shoe soles, shock-absorbing elastomer cushions, steering wheels, armrests, filters, seats, and the like.

The invention has the beneficial effects that:

(1) the foam has a density of 250-350kg/m³The surface density is higher than the core density.

(2) Due to the selection of the polyols (b1) and (b2) with better physical strength and lower Tg and the improvement of the fumed silica with open cells or the suspension thereof, the problems of easy shrinkage of the surface and insufficient physical properties of low-density foam are solved, and the conventional density (370 kg/m) is obtained³And above) mechanical strength, surface and bending resistance properties for equivalent applications of sole foams.

(3) In addition, the polyether polyol used in the composition system and the combination with the cell opening agent of the present invention effectively solve the problems that the composition system generally has higher surface activity, which tends to cause bubble or shrinkage defects on the surface and affect the yield when preparing higher shoe soles, and that the problems are more likely to occur in low density foams due to the low density of the foams.

Detailed Description

The raw materials used

Polyol 1(b 1-1): based on glycerol, polypropylene oxide and ethylene oxide, wherein the ethylene oxide content is 15 to 20% by weight, the molecular weight is about 6000, the viscosity at 25 ℃ is 1000-1500mPa.s

Polyol 2(b 1-2): based on 1, 2-propylene glycol, polypropylene oxide and ethylene oxide, wherein the ethylene oxide content is from 20 to 30% by weight, the molecular weight is about 4000, the viscosity at 25 ℃ is 700-

Polyol 3(b 2-1): polytetrahydrofuran polyether with molecular weight of 2000 and functionality of 2, which is solid at normal temperature and added after being heated and melted;

polyol 4(b 2-2): the block copolymerized polyol of polycaprolactone and polypropylene oxide has a molecular weight of 2000-3000 and a functionality of 2

1, gas silicon: hexamethyl silazane based surface modified fumed silica, specific surface area 220 square meter per gram

Gas-silicon composition 1: the concentration of the solution of hexamethylsilazane-based surface modified fumed silica (specific surface area is 260 square meter/g) and dimethyldichlorosilane surface modified fumed silica (specific surface area is 170 square meter/g) (the mass ratio of the two is 3: 1) in polydimethylsiloxane (viscosity is 200cst) is 25 wt%

Gas-silicon composition 2: the hexamethyldisilazane-based surface modified fumed silica (specific surface area 260 square meters per gram) is mixed with a mixture (mass ratio of 1: 0.1: 1.5) consisting of 3-aminopropyltriethoxysilane and liquid polyisoprene (molecular weight 2000) in a solution of polydimethylsiloxane (viscosity 150-200cst), and the concentration is 50 wt%

Gas-silicon composition 3: the hexamethyldisilazane-based surface modified fumed silica (specific surface area 260 square meters per gram) is mixed with a mixture (mass ratio of 1: 0.2: 3) consisting of 3-aminopropyltriethoxysilane and liquid polyisobutylene (molecular weight 2000), and the solution of the mixture in polydimethylsiloxane (viscosity 150-200cst) has the concentration of 65 wt%

Gas-silicon composition 4: octyl silane surface modified gas silicon product (specific surface area 260 square meters per gram), mixture (mass ratio of 1: 0.1: 2) composed of 3-aminopropyl trimethoxy silane and liquid polyisobutylene (molecular weight 2000) and solution in polydimethylsiloxane (viscosity 150-200cst), the concentration is 40 wt%

Chain extender 1: dipropylene glycol

Chain extender 2: ethylene glycol

Chain extender 3: 1, 4-butanediol

A crosslinking agent: glycerol

Catalyst 1: 1, 4-diazabicyclo [2.2.2] octane dissolved in ethylene glycol

Catalyst 2: from Wanhua

KC152

Emulsified silicone oil: from winning creations

DC3043

Isocyanate 1: 4, 4' -MDI

Isocyanate 2: 4,4 '-MDI comprising about 25% by weight of carbodiimide-modified 4, 4' -MDI.

Examples and comparative examples

The polyurethane foams of the examples and comparative examples, in which the molding was prepared using the prepolymer, were prepared as follows:

(1) the component A is prepared according to the following method:

adding 65.54 parts by weight of isocyanate 1 and 5.65 parts by weight of isocyanate 2 into a reaction vessel, introducing nitrogen, adding 39.55 parts by weight of polyol 2, reacting at 80 ℃ for 2 hours in a heat preservation way, continuously adding 2.26 parts by weight of chain extender 1 into the reaction vessel, reacting at 80 ℃ for 1 hour in a heat preservation way, testing indexes such as NCO content and viscosity (25 ℃) after reaction time is reached, and discharging and packaging after the indexes conform to design values. The prepolymer prepared has an NCO content of 18.6-19.1% and a viscosity of 700-900mPa.s at 25 ℃ as measured.

(2) The preparation method of the component B and the corresponding molding is as follows:

uniformly mixing the raw materials according to the formulas shown in the table 1 and the table 2 to obtain a component B;

keeping the temperature of the component A and the component B at 30-50 ℃; quickly mixing and stirring by a casting head mixer, casting into a metal mold which is coated with a release agent in advance and has a constant temperature of 55 ℃, keeping the temperature for 3-4 minutes, opening the mold, and taking out a molded product; standing at room temperature for at least 48 hours, and testing various physical indexes.

TABLE 1 formulation of B-part of comparative example foaming composition (parts by weight)

	Comparative example 1	Comparative example 2	Comparative example 3
				Polyol 1(b1)	67.34	67.34	58.92
Polyol 2(b1)	16.84	16.84	16.84
				Polyol 3(b2)			8.42
H₂O	0.59	0.59	0.59
				Gas silicon 1		0.04
Chain extender 2	6.73	6.73	6.73
				Chain extender 3	5.05	5.05	5.05
Crosslinking agent	0.17	0.17	0.17
				Catalyst 1	1.85	1.85	1.85
Catalyst 2	0.84	0.84	0.84
				Emulsified silicone oil	0.59	0.59	0.59

TABLE 2 example B part formulation (parts by weight) of foaming composition

(3) Comparison of results

TABLE 3 comparison of physical Properties of comparative examples and examples results and comparison

The test method and the standard are selected from density: calculated for bulk density, mass/volume of the molded body; tensile strength and elongation at break: GB/T528-2009; tear strength: GB/T529-2008; shore a hardness: GB/T531.1-2008 or ISO 7619-1: 2010; and (3) folding endurance test: SATRA TM 133.

From the observation of the molded body and the comparison of the above results, it was found that the use of polyols 3 and 4 in example (b2) provides an improved effect on the physical properties of the molded body as compared with the comparative example, and particularly in examples 5 to 8, the use of polytetrahydrofuran polyether in combination with polycaprolactone/polyoxypropylene polyol to produce 300kg/m³Compared with the low-density foam, the prepared low-density foam has better physical property indexes in a comparative ratio, has comprehensive higher strength, resilience and folding resistance indexes, and simultaneously keeps the foam surface bright and not shrunk; in addition, as can be seen by comparison, the foam without bubbles on the surface can be obtained by using only fumed silica in examples 1-2 and 5-6, so that the problems of shrinkage and surface bubbles of the low-density polyether polyurethane foam are effectively improved, the fineness and the physical property level of foam pores are not influenced, but the foam surface is slightly in a matte state, the brightness of the foam surface is reduced, and the foam appearance is influenced to a certain extent; in more preferred examples 3 to 4 and examples 7 to 8, foams having a bright surface, no bubbles, and good dimensional stability were obtained, and the physical properties such as the bending resistance of the foams were also improved.

Claims

1. A low-density polyurethane microporous foam composition is prepared from the following raw materials in parts by weight:

(a) 30-150 parts of polyisocyanate

(c) 0.02-5 parts of pore forming agent

(d) Chain extender 1-25 parts

(e) 0 to 10 portions of cross-linking agent

(f) 0.5-5 parts of catalyst

(g) 0.1-3 parts of emulsified silicone oil

(h) 0-10 parts of other auxiliary agents and/or additives.

2. Composition according to claim 1, characterized in that the polyisocyanate (a) is chosen from aliphatic, cycloaliphatic and aromatic di-or polyfunctional isocyanates, preferably 4, 4' -MDI, optionally containing from 0 to 20% by weight of carbodiimide or uretonimine modified polyisocyanates.

3. Composition according to claim 1 or 2, characterized in that the (b) compound having at least two hydrogen atoms reactive toward isocyanates comprises (b1) and (b2) in a weight ratio of (b1) to (b2) of (0.5 to 20): 1, preferably (1-15): 1;

wherein (b1) is a polyether polyol of primary OH groups, having a molecular weight of 4000-8000g/mol and a functionality of 2-4;

(b2) is one or more of polytetrahydrofuran polyol, polycaprolactone polyol and polycaprolactone initiated polyoxypropylene polyol.

4. The composition as claimed in claim 3, wherein (b1) is polyoxypropylene-polyoxyethylene block copolyol having a molecular weight of 5000-8000g/mol, wherein the polyoxyethylene polyol block content is 15-30%; or a polymer-grafted polyether polyol, which is a polystyrene-acrylonitrile polymer-grafted polyoxypropylene polyol having a content of 20-40% by weight.

5. The composition as claimed in claim 3, wherein the polytetrahydrofuran polyol has a molecular weight of 1000-3000g/mol and a functionality of 2-3, and the polycaprolactone polyol or polycaprolactone-initiated polyoxypropylene polyol has a molecular weight of 1000-3000g/mol and a functionality of 2-4.

6. The composition of claim 1, wherein (c) the cell opener comprises hydrophobically modified fumed silica; preferably, the pore opening agent is a composition of hydrophobic modified fumed silica, a silane coupling agent and nonpolar alkane according to the weight ratio of 1 (0.1-0.5) to (1-5).

7. The composition as claimed in claim 6, wherein the modifying group of the hydrophobically modified fumed silica includes but is not limited to hexamethylsilazane, dimethyldichlorosilane, octylsilane, hexadecylsilane, the specific surface area of the hydrophobically modified fumed silica is 100-500m²Per g, preferably 200-350m²/g。

8. The composition according to claim 6 or 7, wherein the silane coupling agent is selected from the group consisting of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, methyltrimethoxysilane, n-octyltrimethoxysilane;

the nonpolar alkane is selected from liquid polybutadiene, liquid polyisobutene and liquid polyisoprene, and has the molecular weight of 500-3000 g/mol.

9. The composition as claimed in claim 1, wherein the chain extender (d), having a molecular weight of 50 to 300g/mol, is selected from the group consisting of C-alkanediols having 2 to 12 carbon atoms, dialkylene glycols having 4 to 8 carbon atoms, alkanolamines having 2 to 12 carbon atoms, the C-alkanediols having 2 to 12 carbon atoms including but not limited to ethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 1, 7-heptanediol, 1, 8-octanediol, 1, 9-nonanediol, 1, 10-decanediol, the dialkylene glycols having 4 to 8 carbon atoms including but not limited to diethylene glycol and dipropylene glycol, the alkanolamines having 2 to 12 carbon atoms including but not limited to ethanolamine, 2-aminopropanol; and/or:

the crosslinking agent (e) is selected from the group consisting of trifunctional or higher alcohols including, but not limited to, glycerol, trimethylolpropane, pentaerythritol and trihydroxycyclohexane, trialkanolamines including, but not limited to, triethanolamine.

10. The composition as claimed in claim 1, wherein the foam density is 100-450kg/m³Preferably 200-400kg/m³More preferably 250-350kg/m³Applications include, but are not limited to, shoe soles, shock absorbing elastomeric pads, steering wheels, arm rests, filters, seats.