KR100712457B1 - High-density and soft polyurethane foam having micro-cellular structure and method for preparing the same - Google Patents

Abstract

The present invention relates to a high-density polyurethane soft foam having a micro-cell structure and a method for preparing the same, and more particularly, to form a micro-cell structure under optimal reaction conditions using polyols of various molecular weights, diphenylmethane diisocyanate and catalysts. The present invention relates to a method for producing a polyurethane flexible foam, which has remarkably improved vibration and shock absorption effects, which have improved elasticity and physical properties.

According to the method of the present invention, a high density polyurethane flexible foam having a micro cell structure can be produced. High-density polyurethane soft foam prepared according to the method of the present invention can be used as a high quality material that absorbs vibration and shock having optimal properties such as high elasticity, cold resistance, breathability, durability.

Polyurethane foam, isocyanate, polyol

Description

High-density polyurethane flexible foam having a micro cell structure and a method of manufacturing the same {HIGH-DENSITY AND SOFT POLYURETHANE FOAM HAVING MICRO-CELLULAR STRUCTURE AND METHOD FOR PREPARING THE SAME}

The present invention relates to a high-density polyurethane soft foam having a micro-cell structure and a method for preparing the same, and more particularly, to form a micro-cell structure under optimal reaction conditions using polyols of various molecular weights, diphenylmethane diisocyanate and catalysts. The present invention relates to a method for producing a polyurethane soft foam, which has remarkably improved vibration and shock absorption effects, which improves elasticity and physical properties.

Increasing environmental pollution along with industrial development is seriously threatening our lives. Among many environmental pollution, vibration and noise are closely related to our lives, and the damage is also increasing. Vibration damage is caused by the movement of large vehicles such as subways and trains, or occurs in natural phenomena such as earthquakes, and noise is also increasing in our lives along with vibrations.

It is required to develop advanced materials that can effectively block environmental pollution such as vibration and noise. In Europe, polyurethane-based elastic foam of micro-cellular type has been developed and commercialized. I use it.

In Korea, the import volume of polyurethane foam for vibration and noise isolation is increasing. Currently, imported products for vibration and noise isolation have been used in bridges, high-speed railways, subways, etc., and the demand is expected to continue to increase. Therefore, it is urgent to develop a product that maintains equal or better quality that can replace imported products in terms of economy and industry.

As a conventional technique in this field, there are domestic patent applications 2001-7009037, 2002-66607, and 2004-7003172. The patent applications feature the provision of high pressures for foaming, addition of polyether polyols and alkyl oxides for flexible foams. In particular, in the case of the domestic patent application No. 2002-66607, a polyether polyol containing at least 5% by weight or more of oxyethylene groups (with respect to the weight of the total polyol) inside the chain and the terminal of which is sealed with a secondary OH group It is characterized by.

However, despite the continuous research efforts as described above, due to the inadequate preparation and mixing ratio of the prepolymer having the proper properties of the polyol and diisocyanate constituting the polyurethane, poor quality products that do not reach the desired properties Is being produced. Accordingly, in the present invention, as a result of intensive studies to develop the optimum polyether polyol composition and foaming conditions for producing a high-quality polyurethane-based flexible engineering foam, the present invention has been achieved.

It is an object of the present invention to provide a high density polyurethane flexible foam of microcell structure with improved high elasticity, cold resistance, breathability, and durability.

Another object of the present invention is to provide a method for producing a high density polyurethane flexible foam having a microcell structure under the optimum mixing ratio and reaction conditions of the polyol component and the isocyanate prepolymer.

In one aspect, the invention

1) preparing a polyol substrate by mixing two or more polyols, chain extenders, catalysts, blowing agents, water and additives selected from polyols having a molecular weight of 2500 to 7000;

2) preparing an isocyanate prepolymer by mixing two or more polyols selected from polyols having a molecular weight of 4000 to 7000 with isocyanates;

3) It relates to a method for producing a high-density polyurethane flexible foam having a microcell structure, characterized in that prepared by mixing the isocyanate prepolymer and the polyol substrate at a temperature of 30 to 40 ℃ and then foaming.

In general, the foaming process of polyurethane is achieved by balancing the resination of polyol with isocyanate and blowing of water and isocyanate. This balance is important because the selection of the appropriate catalyst according to the reactivity of the polyol.

In the present invention, the polyol may be selected from two or more of polyols having a molecular weight of 2500 to 7000, preferably a triol having a molecular weight of 6000 to 7000, a solid diffusion polyol having a molecular weight of 3000 to 5000 or a molecular weight 2 or more types of polyols chosen from linear polyols of 2500-4000. Preferably, the polyol is a low monool polyol having a molecular weight in the range of 2500 to 7000 and a monool content of less than 1%. Polyol refers to having at least two -OH groups in the chain, and monool refers to having one -OH group in the chain. The less the monool is contained, the better the reactivity of the polyol is, thereby improving the physical properties of the polyurethane foam.

Polyols usable in the present invention are preferably 1,4-butanediol, Polyoxipropylene Diol, Polyoxipropylene Triol, Polyoxipropylene Tetrol and the like.

In order to increase elasticity, a polyol having a relatively high molecular weight is selected and used, and a polyol having good crosslinkability is used. If the same molecular weight (functionality) more (f = 2.7 or more) can increase the elasticity. The physical properties show the desirable properties as the molecular weight is larger, but when the functional group is increased to f = 2.8 or more, the physical properties deteriorate, and when f = 3, the elasticity increases, but the physical properties decrease relatively.

Two or more polyols selected from the above polyols are mixed with catalysts, blowing agents and / or additives according to the application to produce a polyol substrate.

In order to control the reactivity of the polyol, the present invention adds a catalyst to the polyol substrate, and the catalyst usable in the present invention includes, for example, triethylenediamine, dibutyl tin dilaurate, 1,4-diazabicyclo [ 2,2,2] octane (1,4-Diazabicyclo [2,2,2] octane), bis (2-dimethylaminoethyl) ether, trimethylaminoethylethanolamine ), N, N, N ', N', N "-pentamethyldiethylenetriamine (N, N, N ', N', N" -Pentamethyldiethylenetriamine), N, N'-dimethylethanolamine (N, N '-Dimethylethanolamine), dimethylaminopropylamine, N-Ethylmorpholine, N, N-dimethylaminoethylmorpholine, N, N-dimethylcyclohexylamine N, N-dimethylcyclohexylamine), N, N-dimethylcyclohexylamine, and the like, preferably triethylenediamine .

In the present invention, as the blowing agent, water included in the polyol substrate may be used. The water contained in the polyol substrate finally acts as a blowing agent upon mixing the polyol substrate with the isocyanate prepolymer. Additives such as blowing agents and surfactants may use all compounds usable in the art, and are not particularly limited.

In the present invention, as isocyanate, diphenylmethane diisocyanate (MDI), 2,4-toluene diisocyanate (TDI, 2,4-Toluen Diisocyanate), having low toxicity and relatively high reactivity by vapor pressure, 2 , 6-toluene diisocyanate (TDI, 2,4-Toluen Diisocyanate), hexamethylene diisocyanate (HDI, Hexamethylene Diisocyanate), isophorone (IPDI, Isophoron Diisocyanate) and the like can be used.

The isocyanate is mixed with two or more polyols selected from polyols having a high molecular weight, preferably polyols having a molecular weight of 4000 to 7000, to prepare an isocyanate prepolymer.

The polyol base and the isocyanate prepolymer are separately prepared and mixed. In this way, by lowering the% NCO value of the isocyanate, a high density polyurethane foam having a uniform density of 150 or more can be produced, and also the reactivity and durability are controlled. It can be improved to produce a polyurethane foam having the desired physical properties.

Isocyanate prepolymers according to the present invention may further comprise glycols.

In the present invention, the amount of polyol base and isocyanate prepolymer used is calculated as the total amount of glycols containing functional groups among the raw materials constituting the polyol base (OH value), and then the required amount as the NCO percentage value of the prepolymer (Prepolymer). Calculate the compounding ratio. Generally, 5% excess of the isocyanate prepolymer is added to the required amount of isocyanate in a weight ratio, and if necessary, 20-30% may be insufficiently added. If it exceeds the blending ratio, the hardness increases and elasticity decreases. If it is less than the blending ratio, the hardness decreases and the reactivity decreases. The present invention uses an isocyanate prepolymer in an amount of about 2 to 5% excess of the weight of the polyol substrate, thereby reducing the unreacted glycol to a minimum to improve the compression setting characteristics.

Hereinafter, the present invention will be described in more detail with reference to the following Examples. The following examples are intended to illustrate the invention and the scope of the invention is not limited by the following examples.

Example 1 Preparation of Polyol Substrates

The mixing ratio of the polyol composition for preparing the polyurethane foam having a micro cell structure is shown in Table 1 below.

Polyol Mixing Ratio for Polyurethane Foam Compound name Weight ratio (%) PU-1 PU-2   Polyol A 49   Polyol B 40 -   Polyol C 74   Polyol D 20   Chain extension polyol 95 5.0   water 3 2 ²   Amine Catalyst 1 2 4   Amine Catalyst 2 6 5   Metal catalyst 0.3 0.03   Surfactants 3 4 Total weight 100. ³ 100. ²³

Polyol A: Polyol with molecular weight of 6,000

Polyol B: Polyol with molecular weight of 4,000

Polyol C: Polyol with a molecular weight of 7,000

Polyol D: Solid Dispersion polyol (20-40% of polystyrene particles dispersed in a 5,000-molecular weight polyol)

Example  2 : Polyol  Manufacture of substrate

The mixing ratio of the polyol composition for producing the polyurethane foam having a micro cell structure is shown in Table 2 below.

Polyol Composition for Polyurethane Foam Sample name U-1 U-2 U-3 U-4 Polyol A 72.85 Polyol B 72.85 Polyol C 72.85 52.85 Polyol D 20 Polyol E 20 20 20 20 Chain extension polyol 5 5 5 5 water 0.25 0.25 0.25 0.25 Catalyst 1 0.5 0.5 0.5 0.5 Catalyst 2 0.4 0.4 0.4 0.4 Surfactants One One One One Total weight 100 100 100 100

Polyol A: Polyol having a molecular weight of 6,000

Polyol B: Polyol having a molecular weight of 4000

Polyol C: Polyol A with molecular weight of 7,000

Polyol D: Polyol B with molecular weight of 7,000

Polyol E: Solid Dispersion Polyol with Molecular Weight 5,000

In Table 2, 1,4-butanediol (1,4-Butandiol) as the polyol for chain expansion, triethylene diamine as the catalyst 1, bis (n, n-dimethyl-3-amino-propyl as the catalyst 2) ) Amine (Bis (n, n-dimethyl-3-amino-propyl) amine), and polyether-modified polysiloxane was used as a surfactant.

Example 3 Preparation of Isocyanate Prepolymers

Isocyanate prepolymers were synthesized using MDI monomers and high molecular weight polyols. The synthesis time was on average between 2-3 hours and the temperature did not exceed 80 ℃.

Composition of Isocyanate Prepolymer Sample name MU-1 Weight ratio (%) MDI Monomer 63.0  Polyol A 16.5  Polyol C1 16.5 Glycol 4.00 Total weight 100

Polyol A: Polyol with molecular weight of 6,000

Polyol C1: Polyol A with molecular weight of 7,000

Example  3: isocyanate Prepolymer  Produce

According to the composition ratios shown in Table 4, isocyanate prepolymers were synthesized using MDI monomers and high molecular weight polyols, and the percentage of NCO groups was adjusted to 14-18%. The synthesis time was an average of 2-3 hours and the temperature did not exceed 80 ℃.

Isocyanate Prepolymer Mixing Ratio M-1 M-2 M-3 MDI Monomer 45.1 40.3 53.7 Liquid MDI 0 17.3 2.8 Polyol A 54.9 0 43.5 Polyol D 0 42.5 0 Total weight 100 100.1 100 % NCO 14% 18% 18%

Example  4 : Polyol  And Diisocyanate  Reactant Composition Ratio

Polyurethane Foam Properties EPU-1 EPU-2 Compounding ratio (PU-1 / MU-1) 100/45 - Compounding ratio (PU-2 / MU-1) - 100/45 Density (kg / m ³ ) 380 430 Tensile Strength (N / mm ² ) 1.90 1.78 Tear strength (N / mm) 7.4 9.4 % Elongation 280 390 Permanent Compression Rate (%) 2.1 0.9 Static modulus of elasticity 1.72 2.07 Dynamic modulus 3.25 3.57

Example 5 Polyol and Diisocyanate Reaction Composition

Polyurethane foams were prepared using U-1 as the polyol substrate and M-1, M-2 and M-3 as the isocyanate prepolymer. The most suitable isocyanate prepolymers were selected and varied polyol experiments were conducted. The test results show that the tensile strength and the elongation increase in proportion, but inversely with the elasticity.

Polyurethane Foam Properties Using U-1 Polyol Substrate EPU-3 EPU-4 EPU-5 Compounding ratio (U-1 / M-1) 100/59 Compounding ratio (U-1 / M-2) 100/46 Compounding ratio (U-1 / M-3) 100/46 Density (kg / m ³ ) 410 412 408 Tensile Strength (N / mm ² ) 0.66 0.77 0.61 Tear strength (N / mm) 1.43 2.11 2.07 % Elongation 244 257 147 Permanent Compression Rate (%) 7 12 5 Ball modulus 55 47 58

According to the method of the present invention, a high density polyurethane flexible foam having a micro cell structure can be produced. High-density polyurethane soft foam prepared according to the method of the present invention can be used as a high quality material that absorbs vibration and shock having optimal properties such as high elasticity, cold resistance, breathability, durability.

Claims (5)

 1) preparing a polyol substrate by mixing two or more polyols, chain extenders, catalysts, blowing agents, water and additives selected from polyols having a molecular weight of 2500 to 7000; 2) preparing an isocyanate prepolymer by mixing two or more polyols selected from polyols having a molecular weight of 4000 to 7000 with isocyanates; 3) A method for producing a high-density polyurethane flexible foam having a micro-cell structure, which is prepared by mixing the isocyanate prepolymer and the polyol substrate at a temperature of 30 to 40 ° C. followed by foaming. The method according to claim 1, wherein the polyol in step 1) is a polyol having a molecular weight in the range of 2500 to 7000, and a polyol having a monool content of less than 1%. The compound of claim 1, wherein the isocyanate is at least one compound selected from the group consisting of diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, hexamethylene diisocyanate and isophorone. Characterized in that the method. 2. The catalyst of claim 1 wherein the catalyst is triethylenediamine, dibutyl tin dilaurate, 1,4-diazabicyclo [2,2,2] octane, bis (2-dimethylaminoethyl ethyl) ether, trimethylamino Ethyl ethanolamine, N, N, N ', N', N "-pentamethyldiethylenetriamine, N, N'-dimethylethanolamine, dimethylaminopropylamine, N-ethylmorpholine, N, N-dimethylamino At least one compound selected from the group consisting of ethyl morpholine, N, N-dimethylcyclohexylamine, and N, N-dimethylcyclohexylamine. A high density polyurethane flexible foam having a micro cell structure made by the method according to any one of claims 1 to 4.