KR100738140B1 - Polyurethane Foam, which has been used in Automotive Interior Parts, improved in Mechanical Properties - Google Patents

Abstract

The present invention relates to a polyurethane foam for automotive interiors with improved mechanical properties, and more particularly, by combining a foaming agent of cyclopentane and water with additives such as catalysts and surfactants in addition to polyols and diisocyanate compounds, The present invention relates to a polyurethane foam excellent in mechanical properties such as hardness and compressive strength without increasing the density of the polyurethane foam applied as an interior material, and a manufacturing method thereof.

Mechanical Properties, Polyurethane Foam, Polyols, Diisocyanate Compounds, Cyclopentane

Description

Polyurethane Foam, which has been used in Automotive Interior Parts, improved in Mechanical Properties

1 is a micro-cell structure electron micrograph of the polyurethane foam prepared by Comparative Example 1 (a), Example 2 (b) and Comparative Example 2 (c).

The present invention relates to a polyurethane foam for automotive interiors with improved mechanical properties, and more particularly, by combining a foaming agent of cyclopentane and water with additives such as catalysts and surfactants in addition to polyols and diisocyanate compounds, The present invention relates to a polyurethane foam for automobile interior materials and a method of manufacturing the same, which have superior mechanical properties such as hardness and compressive strength without increasing the density of polyurethane foam applied as interior materials.

Polyurethane foam is generally prepared by foaming with a blowing agent such as water, chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, carbon dioxide, and cyclopentane using diisocyanate compounds and polyols as raw materials.

Toluene diisocyanate (TDI) and 4,4'- diphenylmethane diisocyanate are widely used as a diisocyanate compound. As the polyol, polyether polyols and polyester polyols are largely used. Polyether-based polyols are widely used because of their low viscosity, easy processing, stable hydrolysis, and low cost. Polyester-based polyols have excellent thermal stability, excellent tensile strength, and excellent resistance to oil. I have a disadvantage that the price is expensive. Therefore, more than 90% of polyether-based polyols are used in polyurethane production, and polyester-based polyols are used for special purposes. In addition, low molecular weight diols or diamines are used as chain extenders or crosslinking agents of polyurethane chains. Conventionally, chlorofluorocarbons and hydrochlorofluorocarbons which are stable in the air have been widely used as blowing agents, but in recent years, due to environmental degradation, polyurethane foams for automobiles are manufactured using water as a blowing agent. When water is used as a foaming agent, it is very good in terms of price and environment. However, in order to control the density and hardness of the polyurethane foam due to too high calorific value and viscosity increase during the polyurethane foam formation reaction, the selection of raw materials and the amount of blowing agent added are limited. There is a disadvantage. Cyclopentane is an inexpensive and eco-friendly blowing agent, which attracts much attention because it has no environmental pollution such as ozone depletion and global warming.However, many studies have been conducted to improve the flame retardancy due to the problem of deterioration of flame retardancy due to the explosive property of cyclopentane. Doing. Tin catalysts and amines are used as catalysts, and a flame retardant may be added due to the low flame retardancy of polyurethane. Flame retardants are divided into reactive flame retardants and additive flame retardants. The flame retardants are largely divided into halogen-based, phosphorus-based and inorganic flame retardants. In addition, when a small and uniform cell is formed during foam formation due to foaming, it advantageously acts on mechanical properties. For this purpose, a silicone-based surfactant may be added as a cell stabilizer.

Automotive lightweight technology is a very important technology in light of international trends that are intensifying environmental concerns and regulations. In order to reduce the weight of automobiles, the physical properties of lightweight alternative materials should be equal or better than those of existing materials. In the case of polyurethane foam mainly used for interior materials such as car seat pads, if the hardness or stiffness can be improved at the same density, it can be used to reduce the weight of the car because a lower density polyurethane can be used.

In order to improve the hardness and rigidity of the polyurethane foam for automobile interior materials, there is a method of increasing the density or using filler such as glass fiber or carbon fiber, but both methods increase the weight and cost of the polyurethane foam. .

Therefore, there is an urgent need for research to improve mechanical properties such as hardness and rigidity of polyurethane foam for automobile interior materials without increasing costs without increasing density or using filler.

Accordingly, the present inventors have made efforts to secure a polyurethane foam manufacturing technology for automobile interior materials having increased hardness and rigidity without using rising or fillers, but use cyclopentane as a foaming agent to establish an optimum blending ratio to change the internal microcell structure. The present invention was completed by confirming that the present invention may have improved mechanical properties even when manufactured at a lower density than the polyurethane material for automobile interior materials.

Accordingly, an object of the present invention is to provide a polyurethane foam for automobile interiors in which mechanical properties are improved without increasing density by using a certain amount of cyclopentane, which is completely free of environmental pollution.

In addition, another object of the present invention is to provide a method for manufacturing the polyurethane foam for automobile interior.

The present invention is a polyurethane with improved mechanical properties containing 30 to 60 parts by weight of diisocyanate compound, 2.0 to 15.0 parts by weight of cyclopentane, 0.5 to 4.0 parts by weight of water and 0.5 to 5.0 parts by weight of amine catalyst based on 100 parts by weight of polyol. It is characterized by a foam.

The present invention will be described in more detail as follows.

The present invention is formulated with a specific amount of cyclopentane and water blowing agents in addition to polyols and diisocyanate compounds with additives such as catalysts and surfactants, compressive strength including hardness without increasing the density of polyurethane foam applied to interior materials such as car seat pads The present invention relates to a polyurethane foam having excellent mechanical properties such as that of a conventional product and a method of manufacturing the same.

That is, in the polyurethane foam for automobile interior according to the present invention, since the cyclopentane, which is a physical foaming agent, is used as a specific amount of foaming agent, the size of the microcells in the interior is reduced, thereby improving physical properties such as hardness and rigidity.

The diisocyanate compound used in the present invention is not particularly limited as long as it is commonly used in polyurethane production, and 4,4'-diphenylmethane diisocyanate (4,4'-diphenylmethane diisocyanate polymer and 4,4 ') All diphenylmethane diisocyanates, hereinafter referred to as MDI), toluene diisocyanate (hereinafter referred to as TDI), derivatives thereof or mixtures thereof can be used. The preferred content thereof is 30 to 60 parts by weight with respect to 100 parts by weight of polyol. When it is less than 30 parts by weight, the polyol component is excessively present, the surface is very sticky after the polyurethane is formed, and the unreacted polyol is continuously dropped after the product is formed. There is a disadvantage in that it can come out, if the weight exceeds 60 parts by weight rigidity of the polyurethane foam to be produced is too high that it is easy to break or uniform mixing does not have the disadvantage of forming a product.

MDI used in the present invention is an average functional group of 2.0 to 3.1 in the liquid phase at room temperature and its molecular structure is represented by the following formula (1).

The polyol used in the present invention is not particularly limited as long as it is conventionally used in the production of polyurethane, and polyether polyol as well as polyester polyol may be used. The polyether polyol is particularly widely used because of its low viscosity, which is easy to process, stable to hydrolysis, and inexpensive. Polyester polyol has excellent thermal stability, excellent tensile strength, and excellent resistance to oil. While there are advantages, there are disadvantages that the price is expensive.

The polyether polyol may be ethylene glycol, 1,2-propane glycol, 1,3-propylene glycol, butylene glycol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol, 2-methyl-1, 3-propanediol, glycerol, trimethylolpropane, 1,2,3-hexanetriol, 1,2,4-butanetriol, trimethylolmethane, pentaerythritol, diethylene glycol, triethylene glycol, polyethylene glycol, Tripropylene glycol, polypropylene glycol, dibutylene glycol, polybutylene glycol, sorbitol, sucrose, hydroquinone, resorcinol, catechol, bisphenol or a mixture of two or more thereof; It may be prepared by polymerizing ethylene oxide, propylene oxide or a mixture thereof, but is not limited thereto.

In addition, the polyester polyol is phthalic anhydride or adipic acid; It may be prepared by polymerizing ethylene oxide, propylene oxide, or mixtures thereof, in addition to any of those known in the art can be used.

Polyurethane foam according to the present invention may be prepared by further comprising a diol, triol, tetraol, diamine or amino alcohol as a chain extender, which serves to increase the molecular weight by extending or crosslinking the chain of the polyurethane Do it. Ethylene glycol, propylene glycol, 1,4-butanediol, and the like are used as the diol, glycerin is used as the triol, and pentaerythritol is used as the tetraol. In addition, hexamethylenediamine, m-phenylene diamine, etc. can be used as a diamine, A diethanolamine, a triethanolamine, etc. can be used as an amino alcohol.

In addition, the polyurethane foam according to the present invention may further include a cell stabilizer, a flame retardant, or a mixture thereof.

The flame retardant is added to improve the low flame retardancy of the polyurethane foam is divided into a reactive flame retardant and an additive flame retardant and can be largely divided into halogen-based, phosphorus-based and inorganic flame retardants. When the cell stabilizer is used to form a polyurethane foam, a small and uniform cell may be generated during foam formation due to foaming. For example, a silicone-based surfactant may be used.

Polyurethane foam according to the present invention comprises the steps of (a) mixing the diisocyanate compound and a polyol and then reacting with stirring; (b) adding cyclopentane and water and foaming the reaction mixture. That is, the production method according to the present invention is characterized in that the polyurethane is formed by reacting a diisocyanate compound with a polyol, and foaming by adding cyclopentane, a physical blowing agent, and water, a chemical blowing agent, to form a polyurethane foam during these reactions. There is this.

In the production method according to the present invention, the reaction temperature in the step (a) is suitably 20 ~ 35 ℃, less than 20 ℃ when the reaction does not occur well when it exceeds 35 ℃ uniform because of too fast reaction rate This is because there is a risk of mixing difficult.

On the other hand, it is preferable that the NCO / OH ratio in the step (a) is 0.7 ~ 1.0 (equivalent ratio), if less than 0.7, the polyol component is present in excessive excess, the surface is very sticky after the polyurethane is formed and the unreacted polyol is It has the disadvantage of being able to continuously escape after forming the product, and in case of exceeding 1.0, the rigidity of the polyurethane foam to be manufactured is too high to be easily broken, or it is difficult to form the product because uniform mixing is not made. have.

In the manufacturing method of the cyclopentane foamed polyurethane foam for automobile interior according to the present invention, pentamethyldiethylenetriamine (pentamethylenediethyeletriamine), dimethylcyclohexylamine, tris (3-dimethylamino) propyl hexahydrotriamine (tris ( Amine catalysts such as 3-dimethylamino) propylhexahydrotriamine) and triethylenediamine may be used, and these may be used alone or in combination. The catalyst is preferably used in the step (a) and is preferably used in 0.5 to 5.0 parts by weight based on 100 parts by weight of the polyol. If the content of the catalyst in step (a) is less than 0.5 parts by weight, a smooth foaming reaction and a curing reaction may not be formed, and there is a problem in that the production time is excessively long. Due to this, it is difficult to achieve uniform mixing, and there is a risk of cell destruction due to excessive reaction speed.

When the polyurethane foam is prepared by mixing the blowing agent in the step (b), it is appropriate that the temperature is 5 to 40 ° C., but when it is less than 5 ° C., the foaming reaction does not occur well, so that a foam having a desired foam structure cannot be obtained and 40 ° C. This is because when the foam is exceeded, there is a concern that a large volcanic crater form is generated in the center of the foam due to tearing of the foam produced due to an excessively rapid foaming reaction or a large amount of foaming gas escapes.

In order to manufacture the polyurethane foam in step (b), water and cyclopentane are mixed and used, wherein water is preferably 0.5 to 4 parts by weight based on 100 parts by weight of polyol and 2 to 15 parts by weight of cyclopentane. In this case, the density of the polyurethane foam to be produced will have a 30 ~ 140 kg / ㎥ and can control the low density foam of less than 30 kg / ㎥ or a high density foam of 140 kg / ㎥ or more by adjusting the amount of the blowing agent. Cyclopentane facilitates the production of polyurethane foams due to the low evaporation temperature and also imparts excellent flowability in the production of polyurethane foams due to the low viscosity. In addition, there is no environmental pollution such as ozone layer destruction and global warming, which are disadvantages of chlorofluorocarbon (CFC) -based and hydroxychlorofluorocarbon (HCFC) blowing agents. Water was used as auxiliary blowing agent and released carbon dioxide while reacting with diisocyanate to form urea, which was used for the foaming of the polyurethane foam. The heat of reaction between water and diisocyanate is also used for vaporization of cyclopentane. Water is preferably used 0.5 to 4 parts by weight based on 100 parts by weight of the mixed polyol. If the water content is less than 0.5 parts by weight, there is a lack of stable reaction heat supply due to the chemical reaction of water and is too sensitive to the reaction temperature. If the reaction temperature is only a little low, the foaming reaction does not occur smoothly. The tearing problem may occur, and if it exceeds 4 parts by weight, the excess of the heat of reaction may cause scorch to be produced in the polyurethane foam, and also cause excessive viscosity increase in the production of polyurethane foam. . If the content of cychloropentane is less than 2.0 parts by weight, the effect of reducing the viscosity of the raw material is reduced, and the effect of reducing the fine cell size of the foam according to the use of cyclopentane is a weak problem. Due to this excessive increase, there is a problem that the foam may be torn or the density and hardness may be so low that the automobile interior material may not have the rigidity to be provided.

Polyurethane foam according to the present invention can be improved by more than 10% in compression, bending, tensile strength than the conventional polyurethane foam at the same density of 46 kg / cm ² .

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Examples 1 and 2 and Comparative Examples 1 and 2

Comparative Examples 1 and 2 and Examples 1 and 2 Polysiloxane ethers, which are surfactants, and pentamethyldiethylenetriamine and dimethylcyclohexyl as catalysts in a polyol polymerized by adding propylene oxide and ethylene oxide to propylene glycol according to the component addition amount of the composition An amine, and cyclopentane and water as blowing agents were added according to the component addition amounts of the compositions of Comparative Examples 1 and 2 and Examples 1 and 2 shown in the following Table 1 to prepare a resin stock solution, wherein 4,4'-diphenylmethane was added thereto. Polyisocyanate foams corresponding to Comparative Examples 1 and 2 and Examples 1 and 2 were prepared by mixing and reacting the diisocyanate in an amount corresponding to the addition amount shown in Table 1 below.

Examples 1 to 2 prepared according to the present invention shown in Table 1 use expensive cyclopentane as a blowing agent compared to water, but the amount of MDI added for the foaming reaction with water is relatively reduced as the use of water, which is a chemical blowing agent, decreases. As a result, the total amount of MDI that is more expensive than cyclopentane can be reduced, resulting in cost savings.

Test Example

The density, mechanical strength, and hardness properties of the polyurethane foam prepared according to Table 1 were measured, and the results are shown in Table 2 below.

[How to measure]

(1) Density: measured by ASTM D1622 method.

(2) Cell size: Cell morphology measurement using Scanning Electron Microscopy.

(3) Compressive strength: measured by ASTM D1621 method.

(4) Bending strength: measured by KS M3830 method.

(5) Tensile strength: measured by ISO 1926 method.

(6) Compressive hardness: measured by ASTM D3574-86 method.

Stiffness characteristics Comparative Example 1 Example 1 Example 2 Comparative Example 2 Density [kg / m ³ ] 46 49 46 46 Cell size [μm] 305 185 190 210 Compressive strength [MPa] 1.68 1.97 1.90 1.61 Bending strength [MPa] 2.35 2.48 2.62 2.05 Tensile Strength [MPa] 1.95 2.03 2.19 1.38 Compression Hardness [kgf / 314m ² ] 22.61 26.02 25.29 23.17

Using an electron microscope, the fine cell structure inside the polyurethane foam prepared according to Comparative Example 1, Example 2, and Comparative Example 2 was observed. Figure 1 shows the microstructure of the cyclopentane-foamed polyurethane foam of the present invention observed with an electron microscope. It can be observed that the polyurethane foams prepared according to the present invention have a smaller cell structure compared to conventional water-foamed polyurethane foams. In addition, the polyurethane foam prepared by using only the cyclopentane as a blowing agent without using water, which is a chemical blowing agent prepared in Comparative Example 2, has a small cell structure compared to the water-foaming polyurethane foam, but is shown in FIG. As can be seen, the destruction of the cell is strongly generated. Water, which is a chemical blowing agent, is suitable for using a small amount of chemical blowing agent because it not only helps the foaming reaction to proceed gradually but also helps to form a stable cell.

As described above, the polyurethane foam according to the present invention can significantly improve the rigidity and hardness of the polyurethane foam for automobile interior materials despite the same density due to the small cell structure.

In addition, the manufacturing method of the polyurethane foam according to the present invention can reduce the manufacturing cost because it can have superior physical properties than the physical properties of the existing product even if the amount of MDI is expensive compared to cyclopentane. In addition, even if the density is reduced due to the increase in hardness and stiffness, the physical properties of the existing product may be secured, thereby contributing to the weight reduction of the automobile interior material due to the lower density.

Claims (8)

30 to 60 parts by weight of diisocyanate compound, 2.0 to 15.0 parts by weight of cyclopentane, 0.5 to 4.0 parts by weight of water, and an amine catalyst based on 100 parts by weight of polyether polyol prepared by addition polymerization of propylene oxide and ethylene oxide to propylene glycol. It contains 0.5 to 5.0 parts by weight, and the NCO / OH ratio is 0.7 to 1.0 equivalent ratio of the polyurethane foam for automotive interiors improved mechanical properties. delete delete The polyurethane foam according to claim 1, wherein the diisocyanate compound is 4,4'-diphenylmethane diisocyanate, toluene diisocyanate, a derivative thereof or a mixture thereof. The polyurethane foam according to claim 1, wherein the amine catalyst is pentamethyldiethylenetriamine, dimethylcyclohexylamine, tris (3-dimethylamino) propylhexahydrotriamine, triethylenediamine or mixtures thereof. . The polyurethane foam according to claim 1, further comprising a flame retardant, cell stabilizer or a mixture thereof. delete delete

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