KR20220074306A - Flexible polyurethane foam compositions comprising a heat release agent and a heat absorber, and manufacturing method of foam using the same - Google Patents

Abstract

The present invention relates to a flexible polyurethane foam composition comprising a heat absorber and a heat release agent, and a method for manufacturing a foam using the same, and specifically, to a foaming stock solution comprising a polyol and an isocyanate, thermoplastic resin particles serving as a heat absorber and heat It relates to a flexible polyurethane foam composition capable of producing a flexible polyurethane foam without changing physical properties, scorching, and yellowing by adding a predetermined amount of graphene serving as a release agent to lower the internal temperature formed during foaming, and a method for manufacturing the same.

Description

Flexible polyurethane foam compositions comprising a heat release agent and a heat absorber, and manufacturing method of foam using the same}

The present invention relates to a flexible polyurethane foam composition comprising a heat absorber and a heat release agent, and a method for manufacturing a foam using the same, and more particularly, to a foaming stock solution comprising a polyol and an isocyanate, thermoplastic resin particles serving as a heat absorber and heat It relates to a flexible polyurethane foam composition capable of producing a flexible polyurethane foam without changing physical properties, scorching, and yellowing by adding a predetermined amount of graphene serving as a release agent to lower the internal temperature formed during foaming, and a method for manufacturing the same.

Flexible polyurethane foam is a foaming product mainly made of polyol, water, and isocyanate. Flexible polyurethane has good cushioning properties and mechanical strength (elongation, tensile strength, abrasion resistance), and can control a wide range of specific gravity and various physical properties according to the formulation, so it is widely used in construction or industrial insulation, water absorption, furniture beds and sofas. .

Flexible polyurethane foam is largely classified into two types according to the production method, and is divided into mold foam and slabstock foam. In the case of slab stock foam, it is a generic term for foam that is produced in a frame of a certain shape by a continuous foaming method and then cut and used according to the purpose.

When manufacturing flexible polyurethane foam, an exothermic reaction proceeds during the foaming reaction, and water (H ₂ O), a chemical foaming agent, reacts with isocyanate to generate carbon dioxide (CO ₂ ), and the temperature inside the foam rises to 200℃, and this reaction is completed It will take quite a while for it to happen. In particular, the scorching phenomenon may occur due to the internal temperature, or the physical properties of the entire polyurethane foam may be changed, and the internal temperature may cause ignition to cause a fire.

Accordingly, polyurethane foam manufacturers are making efforts to reduce the cost of raw materials for cost competitiveness of their products. In order to produce low-density polyurethane foam, a certain component of a foaming agent is used in the main material of polyol and isocyanate. Typically, water (H ₂ O) is used as a chemical blowing agent. In addition, in the case of low-density polyurethane foam, non-flammable and low boiling point methyl chloride (methyl chloride, MC) is used as a physical foaming agent to improve foaming power at low temperatures. Using such a physical foaming agent, it is possible to increase the height and volume of the foam block and to produce low-density products, so it is widely used because it can improve productivity. It is limited, and finally it is forbidden to use it. In addition, chlorofluorocarbon (CF) having an appropriate low boiling point and non-toxicity has been widely used. However, due to the destruction of the morning layer and the problems of global warming, the production and use of it has been banned in developed countries since the early 1990s. After the step-by-step reduction in the use of chlorofluorocarbons, hydrochlorofluorocarbon (HCFC) as an alternative blowing agent has been widely used because of its excellent properties such as a suitable boiling point and low thermal conductivity. However, hydrochlorofluorocarbons also have an ozone depletion potential (ODP) of 0.11, so in developed countries, the use of HCFCs was limited to 2005, ahead of the 2030 Montreal Protocol (Revised in Montreal), which is the HCFC use regulation schedule. In addition, auxiliary blowing agents with a low boiling point generally have a very low flash point. Therefore, it is often the first petroleum that has a low flash point, and to use it, there are considerable difficulties in explosion-proof facilities, facility reinforcement, and maintenance. MC, which has been used in the past, has been widely used as a detergent and auxiliary foaming agent due to its low boiling point and non-flammable properties. However, as it is designated as a substance harmful to the human body, its use is restricted, and its use is expected to be banned eventually.

In the case of high-density flexible polyurethane foam, since the cell structure is dense and a small amount or no physical foaming agent is used, there is a limit to emitting the internal temperature to the outside, so the production volume is inevitably small. In addition, it takes a considerable amount of time such as three days or more to lower the internal heat.

Therefore, if the high temperature inside the flexible polyurethane foam is not released to the outside or the heat of reaction inside is not lowered, ignition, changes in physical properties, scorching, yellowing, etc. occur ^. There is a limit to increasing the block size due to its internal temperature, which affects productivity.

There is growing interest in materials to replace the blowing agent, such as methyl chloride, which were mentioned above. In the case of replacement materials, the ozone depletion potential (ODP) is 0 and the global warming potential (GWP) is gradually lowered, and non-flammable or flammable. In this case, the cost of the explosion-proof facility is high, and it must have the property of having a boiling point at a low temperature. Therefore, if the internal temperature can be lowered, the amount of auxiliary foaming agent used can be reduced or the volume of product production can be increased, thereby improving productivity. The actual block temperature rises up to 200℃, so to effectively lower the internal temperature, the internal heating temperature must be lowered, and the internal temperature must be quickly released to have a great effect.

In order to make a low-density product, the amount of water, which is a chemical blowing agent, must be increased, and accordingly, the more the amount reacts with isocyanate, the more heat is generated. High-density products reduce the amount of chemical foaming agent in order to realize high density, but as the cell size is small and the density increases, the heat going to the outside is trapped. Therefore, there is a limit in that it is difficult to increase the size of a high-density product.

Under this background, the present inventors introduced thermoplastic resin particles with a melting temperature of 180° C. or lower to absorb and lower the internal temperature of the product during the foaming reaction in order to maximize the control of the high internal temperature formed during foaming, and graphene After the foaming reaction is applied, it is possible to quickly release the internal temperature to the outside, thereby lowering the internal temperature after the foam formation process and foam formation, thereby completing the present invention. In other words, the present invention can control the internal temperature by introducing an organic-inorganic hybrid system to which thermoplastic resin particles and graphene are applied, thereby increasing the production size of foam products and improving productivity.

1. Korean Patent Publication No. 10-2019-0124601 (published on Nov. 5, 2019)

An object of the present invention is to solve the problems of the prior art as described above, and to lower the internal temperature formed during foaming by adding a predetermined amount of thermoplastic resin particles as a heat absorber and graphene as a heat release agent to a foaming stock solution containing polyol and isocyanate. , to provide a flexible polyurethane foam composition capable of producing a flexible polyurethane foam without a change in physical properties, scorch, and yellowing, and a method for manufacturing the same.

In order to achieve the above object, the present invention is a polyol 10 to 70% by weight; 10 to 70% by weight of an isocyanate compound; 1 to 10% by weight of a thermoplastic resin powder having a melting point (Tm) value of 180° C. or less; 0.1 to 5% by weight of graphene; And 1 to 5% by weight of a foaming agent; provides a flexible polyurethane foam composition comprising.

In addition, the present invention comprises the steps of: (a) preparing a stock solution by mixing 10 to 70% by weight of an isocyanate compound in 10 to 70% by weight of a polyol; (b) preparing a foamed stock solution by mixing 1 to 10% by weight of a thermoplastic resin powder, 0.1 to 5% by weight of graphene, and 1 to 5% by weight of a foaming agent in the stock solution; And (c) mixing the stock solution and foaming to form a foam, it provides a method for producing a flexible polyurethane foam.

The composition according to the present invention can provide a flexible polyurethane foam capable of producing a flexible polyurethane foam without changing physical properties, scorching, and yellowing by using a heat absorber and a heat release agent. In other words, the flexible polyurethane foam can be manufactured using an organic-inorganic hybrid system using an organic thermoplastic resin and an inorganic graphene.

In addition, since it is possible to lower the internal temperature during foaming, it is possible to reduce the amount of foaming agent used or to increase the volume of product production, thereby improving productivity.

1 is a graph showing the temperature change in the foam manufacturing process of Comparative Examples and Examples. In detail, in the case of raw material PU (Pristine PU), the initial block internal temperature rapidly increased to 190 ℃, and when the thermoplastic resin (TP) was mixed, it decreased to about 170 ℃, and the thermoplastic resin (TP) and graphene (GR) were In the case of mixing, it was confirmed that the internal temperature in the initial foaming reaction was almost similar to that when only the thermoplastic resin (TP) was applied. However, it was confirmed that as time passed after foaming was completed, the internal temperature was dropping more rapidly in the graphene-applied product. In the case of a thermoplastic resin (TP), the heat generated during foaming plays a role in controlling the internal temperature that rapidly rises due to an endothermic reaction as the thermoplastic resin (TP) melts. It was confirmed that this plays a role in the release of internal temperature.

Hereinafter, the flexible polyurethane foam composition of the present invention and a method of manufacturing a foam using the same will be described in more detail.

The inventors of the present invention add a predetermined amount of organic thermoplastic resin particles and inorganic graphene to a foaming stock solution containing polyol and isocyanate to lower the internal temperature formed during foaming, thereby reducing the amount of foaming agent and making it soft without changing physical properties, scorching, or yellowing. Polyurethane foam can be manufactured, and the present invention has been completed by finding that productivity can be improved by reducing the amount of foaming agent used or increasing the volume of product production.

Accordingly, the present invention is a polyol 10 to 70% by weight; 10 to 70% by weight of an isocyanate compound; 1 to 10% by weight of a thermoplastic resin powder having a melting point (Tm) value of 180° C. or less; 0.1 to 5% by weight of graphene; And it provides a flexible polyurethane foam composition comprising 1 to 5% by weight of a foaming agent.

In the present invention, the amount of polyol and isocyanate used is determined by the index (INDEX) of polyol and isocyanate. In the present invention, it is preferable that the polyol and isocyanate compound have an index value of 70 to 130. If the isocyanate index is less than 70, bubbles are not formed properly and foam is not formed. In addition, the index is a unit ratio of isocyanate (NCO) and polyol (OH), and is calculated by Equation 1 below.

[Equation 1]

Isocyanate Index = isocyanate equivalents/polyol equivalents

In addition, the polyol may have a mass average molecular weight of 1,500 to 8,000. If the mass average molecular weight is less than 1,500, there is a limit to mechanical properties, and if it is more than 8,000, there is a limit of foaming due to high viscosity, so it is better to use one within the above range. In addition, in order to satisfy various physical properties and performance, it is preferable to use a mixture of two or more types of products rather than using a polyol alone.

As the isocyanate compound, monoisocyanate, diisocyanate, etc. may be used, and diisocyanate is preferably used, but is not limited thereto, and it is preferable to use a mixture of aromatic isocyanate and aliphatic isocyanate. When an aromatic isocyanate and an aliphatic isocyanate are mixed and used, it is possible to control the rate of pore formation inside the foam when forming the polyurethane foam.

The isocyanate compound preferably has an NCO% of 30 to 50 mass%, but may be changed depending on the type of product.

In addition, the thermoplastic resin serves as a heat absorber for absorbing heat generated in the foaming process, and it is preferable to use a thermoplastic resin having a melting point (Tm) value of 180° C. or less. More preferably, it is good to use a thermoplastic resin having a temperature of 120 to 180°C.

Specifically, the thermoplastic resin is linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), high-density polyethylene (HDPE), ABS (acrylonitrile-butadiene-styrene resin) resin, polypropylene (PP), polyethylene terephthalate (PET), It may be at least one selected from the group consisting of polystyrene (PS), acrylic resin (PMMA), SAN (Styrene Acrylonitrile Copolymers) resin, and polyvinyl chloride (PVC). Preferably, low-density polyethylene (LDPE) or high-density polyethylene (HDPE) or a mixture thereof is used.

In this case, it is preferable to use the thermoplastic resin powder having an average particle size of 100 to 500 μm. More preferably, it is 100 to 200 µm. If the average particle size is less than 100 μm, the volume is large compared to the weight, so the viscosity increases, which may cause problems in the foaming process. Because it does not affect the part, there is a limit to temperature control in the middle and later processes inside the block of flexible polyurethane. It is preferable to use one within the above range.

The graphene serves as a heat release agent for releasing heat to the outside after foaming and forming a foam, and it is preferable to use 0.1 to 5% by weight based on the total weight of the flexible polyurethane foam composition. When graphene is less than 0.1% by weight, there is a limit in that the effect is reduced because barrier ribs and interconnections are not made in the cell structure of the foam, and when it is more than 5% by weight, it is difficult to form a foam due to a rapid increase in viscosity. Because there is a limit, it is recommended to use it within the above range.

The graphene may be graphene oxide or reduced graphene.

The foaming agent may use water, but is not necessarily limited thereto. It is preferable to use 1 to 5% by weight based on the total weight of the flexible polyurethane foam composition. If the foaming agent is less than 1% by weight, there is a problem that the polyurethane foam is not sufficiently foamed. It is preferable to use within the above range because methyl chloride (MC), a physical foaming agent having a low boiling point of the foaming agent, is used together.

In addition, the flexible polyurethane foam composition may further include one or more additives selected from the group consisting of a chain extender, a surfactant, an auxiliary foaming agent, an amine catalyst, a TIN catalyst, a silicone oil, a foam stabilizer, and a pigment. have.

In this case, the auxiliary foaming agent may be methyl chloride (MC), but is not necessarily limited thereto. In the case of low-density foam products of 25 kg/m ³ or less, these auxiliary foaming agents are additionally used in addition to the foaming agent, and due to the low boiling point, low-density foam is produced due to the generation of evaporation during foaming. On the other hand, in the case of high-density foam products, an auxiliary foaming agent is not used to increase the density, but high-density products have difficulty in improving the size of the product due to the internal temperature.

In the present invention, an auxiliary foaming agent can be selected and used according to the low-density foam or high-density foam, and as mentioned above, heat generated in the foaming process is absorbed by the use of a thermoplastic resin, and after foaming by using graphene, the foam is formed. Since it is possible to radiate heat to the outside, it is possible to solve the above difficulties in manufacturing a low-density foam or a high-density foam.

In addition, the present invention comprises the steps of: (a) preparing a stock solution by mixing 10 to 70% by weight of an isocyanate compound in 10 to 70% by weight of a polyol; (b) preparing a foamed stock solution by mixing 1 to 10% by weight of a thermoplastic resin powder, 0.1 to 5% by weight of graphene, and 1 to 5% by weight of a foaming agent in the stock solution; And (c) mixing the stock solution and foaming to form a foam, it provides a method for producing a flexible polyurethane foam.

In step (a), an isocyanate compound is added to the polyol and mixed to prepare a stock solution. As mentioned above, it is preferable to use 10 to 70% by weight of the isocyanate compound in 10 to 70% by weight of the polyol.

Next, step (b) is to prepare a foamed stock solution by mixing the thermoplastic resin powder, graphene, and a foaming agent in the stock solution. The materials used in the method for producing the polyurethane foam are used in the same sense as the materials applied to the polyurethane composition. It is preferable to disperse by rotating at 2,000 to 5,000 rpm for 1 minute when preparing the foaming stock solution, but is not necessarily limited thereto.

Finally, step (c) is a step of mixing and foaming the stock solution to form a foam. In detail, it is preferable to proceed at room temperature of 25° C. so that the polymerization of the polyol raw material and the isocyanate compound can proceed smoothly. Since the urethane reaction is sensitive to temperature, there is a disadvantage that the reaction rate becomes slow when the temperature is too low or zero, and when the temperature exceeds 40° C., the reaction proceeds fairly quickly. Therefore, the polymerization temperature is preferably carried out at 25 to 40 ℃.

A flexible polyurethane foam composition according to the present invention and a manufacturing method thereof include polyol and isocyanate, thermoplastic resin particles serving as a heat absorber, and graphene serving as a heat release agent in a predetermined amount to lower the internal temperature formed during foaming to change physical properties , it is possible to manufacture flexible polyurethane foam without scorching or yellowing.

Hereinafter, the present invention will be described in more detail by way of Examples. However, the present invention is not limited by these examples.

<Comparative Examples and Examples>

Polyurethane foams according to Comparative Examples and Examples were prepared using the components and compositions of Table 1 below. Specifically, the components and compositions of Table 1 were mixed at a stirring speed of 6000 rpm in a foaming stirrer and foamed at a temperature of 25° C. to prepare a flexible polyurethane foam.

division Comparative Example 1
(pristine PU) Comparative Example 2
(PU+TP) Comparative Example 3
(PU+Gra) Example 1
(PU+TP+Gra) Example 2
(PU+TP (use 2 types)+Gra) polyol ¹⁾ 57 55 56 54 54 isocyanate compound ²⁾ 37 35 36 34 34 Thermoplastic resin powder 1 ³⁾ - 5 - 5 3 Thermoplastic resin powder 2 ⁴⁾ - - - - 2 graphene ⁵⁾ - - 2 2 2 blowing agent ⁶⁾ 4 3 4 3 3 chain extender ⁷⁾ One One One One One Surfactant ⁸⁾ One One One One One total content
(Unit: % by weight) 100 100 100 100 100 1) Polyol Polyether-based polyol, mass average molecular weight (MW): 2,000 to 6,000
2) Isocyanate compound: Toluene-diisocyanate (T-80)
3) Thermoplastic resin powder 1: LLDPE
4) Thermoplastic resin powder 2: HDPE
5) Graphene: Graphene oxide (XG Science)
6) Foaming agent: water
7) Chain extender: Stannous octoate (T-9)
8) Surfactant: Octamethylcyclotetrasiloxane (L-580K)

<Experimental Example 1> Measurement of internal temperature change

Comparative Example 1 (pristine PU), Comparative Example 2 (PU + TP), and Comparative Example 3 (PU + Gra), and Example 1 (PU + TP + Gra), a foam composition comprising both graphene and a thermoplastic resin ) was measured by a method using a total of six probes, and the results are shown in FIG. 1 .

As a result of FIG. 1 , Comparative Example 1 (pristine PU) exhibited an internal temperature up to 190° C. during foaming, but it was confirmed that the maximum (MAX) temperature was lowered to about 170° C. when only TP was applied. In the case of Example 1 (PU+TP+Gra), the maximum (MAX) temperature during foaming was almost similar to 168°C, but it was confirmed that the rate of heat release during the aging process was considerably faster than that of the conventional one.

Therefore, the flexible polyurethane foam composition according to the present invention serves as a heat absorber for absorbing heat generated in the foaming process of the thermoplastic resin powder and as a heat release agent for releasing heat to the outside after the graphene foams to form a foam As a result, it was confirmed that the internal temperature formed during the foam manufacturing process was lowered, and the flexible polyurethane foam was able to be manufactured without changes in physical properties, scorching, and yellowing.

<Experimental Example 2> Measurement of physical properties

Using the flexible polyurethane foams prepared in Comparative Examples and Examples as a sample, physical properties were measured in the following manner, and the results are shown in Table 2 below.

(1) Compressive hardness measurement: Extrusion strength was measured using the KS M 6672 method.

(2) Elongation measurement: The elongation was measured according to the KS M ISO 1798 method.

(3) Measurement of tensile strength: Tensile strength was measured using the KS M ISO 1798 method.

(4) Whether or not yellowing: Whether or not yellowing or denaturing was visually confirmed (in case of yellowing denaturation: ○, without yellowing denaturation: ×).

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 Compressive Hardness (Unit: kgf) 13.1 12.7 14.3 13.8 14.6 Elongation (Unit: %) 107 98 116 104 111 Tensile strength (unit: kgf/cm ² ) 0.97 1.12 0.88 1.05 1.2 Whether yellowing X X X X X

As a result of Table 2, it was confirmed that the internal temperature of the block could be controlled while not significantly different from the physical properties of the existing polyurethane (Comparative Example 1) when measuring compressive hardness, elongation, tensile strength, and yellowing.

As described above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited thereto, and the technical spirit of the present invention and the following by those of ordinary skill in the art to which the present invention pertains. It goes without saying that various modifications and variations are possible within the scope of equivalents of the claims to be described.

Claims (10)

10 to 70% by weight of polyol;
10 to 70% by weight of an isocyanate compound;
1 to 10% by weight of a thermoplastic resin powder having a melting point (Tm) value of 180° C. or less;
0.1 to 5% by weight of graphene; and
1 to 5% by weight of a blowing agent;
Including, a flexible polyurethane foam composition.
The method of claim 1,
The polyol has a mass average molecular weight of 1,500 to 8,000, a flexible polyurethane foam composition.
The method of claim 1,
The polyol and the isocyanate compound have an index (INDEX) value of 70 to 130, a flexible polyurethane foam composition.
The method of claim 1,
The graphene is graphene oxide or reduced graphene, characterized in that the flexible polyurethane foam composition.
The method of claim 1,
The thermoplastic resin is linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), high-density polyethylene (HDPE), ABS (acrylonitrile-butadiene-styrene resin) resin, polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS) ), acrylic resin (PMMA), SAN (Styrene Acrylonitrile Copolymers) resin, and polyvinyl chloride (PVC), characterized in that at least one selected from the group consisting of, a flexible polyurethane foam composition.
The method of claim 1,
The thermoplastic resin powder has an average particle size of 100 to 500 μm, characterized in that the flexible polyurethane foam composition.
The method of claim 1,
The graphene serves as a heat release agent for emitting heat to the outside after foaming and forming a foam, and the thermoplastic resin powder serves as a heat absorber for absorbing heat generated in the foaming process, flexible polyurethane foam composition.
The method of claim 1,
The flexible polyurethane foam composition further comprises at least one additive selected from the group consisting of a chain extender, a surfactant, an auxiliary foaming agent, an amine catalyst, a TIN catalyst, a silicone oil, a foam stabilizer, and a pigment. which, a flexible polyurethane foam composition.
(a) preparing a stock solution by mixing 10 to 70 wt% of an isocyanate compound in 10 to 70 wt% of a polyol;
(b) preparing a foamed stock solution by mixing 1 to 10% by weight of a thermoplastic resin powder, 0.1 to 5% by weight of graphene, and 1 to 5% by weight of a foaming agent in the stock solution; and
(c) mixing and foaming the stock solution to form a foam;
A method for producing a flexible polyurethane foam comprising a.
10. The method of claim 9,
The (c) step is a method for producing a flexible polyurethane foam, characterized in that carried out at a reaction temperature of 25 to 40 ℃.

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