KR20150044790A - Polyurethane foam filled with cork, and method thereof - Google Patents

Abstract

The present invention relates to polyurethane foam filled with cork, and also to a method for manufacturing polyurethane foam filled with cork. According to an embodiment of the present invention, the method for manufacturing polyurethane foam filled with cork includes a step in which cork powder is evenly distributed in polyol by using the revolution/rotation mixing method; a step in which bubbles generated in cork polyol is removed; a step in which additives are added to the cork-polyol mixture; and a step in which diisocyanate mixes and reacts with the cork-polyol mixture.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a polyurethane foam filled with cork and a method for producing the same.

The present invention relates to a cork filled polyurethane foam, and also to a method for producing such a cork filled polyurethane foam.

There is a growing demand for environmentally friendly foam and insulation materials due to the strengthening of environmental regulations. In this case, polyurethane is the main insulation material.

Such polyurethanes have a variety of uses, and are usually used where heat insulation performance is required. However, in such a case, the polyurethane has a problem of brittleness which is fragile and easily breakable.

At present, in the case of LNG carriers, the part carrying the liquefied gas is made of polyurethane. In this case, as the amount of the liquefied gas varies in the LNG carrier, there is always a problem that the liquefied gas hits the wall, thereby breaking the wall of the polyurethane material.

In order to solve this problem, up to now, a wall made of a polyurethane material has been made to be thick, but this is costly and has a problem that the space occupied by a ship is widened.

The present invention relates to a technology for dispersing natural cork powder in a polyol through pre-confinement and mixing and reacting a diisocyanate to produce an environmentally-friendly / high-performance polyurethane foam. The cork-polyurethane foam composite produced according to the present invention is lightweight , Mechanical properties such as impact absorption, vibration and acoustic damping performance, resilience, strength and rigidity are greatly improved while maintaining excellent heat insulation performance.

In the present invention, an environmentally friendly heat insulating material is prepared by filling natural cork powder into a rigid polyurethane foam used as a heat insulating material. By manufacturing the polyurethane foam composite material by filling the cork powder, the mechanical properties such as impact absorption, vibration and acoustic damping, recovery force, strength and rigidity are improved while maintaining light weight and excellent heat insulating performance.

A method of manufacturing a cork filled polyurethane foam according to an embodiment of the present invention includes uniformly dispersing cork powder in a polyol using a pre-confinement method; Removing bubbles generated in the cork-polyol mixture; Adding an additive to the cork-polyol mixture; And mixing and reacting the diisocyanate with the cork-polyol mixture.

In this case, the additive includes a catalyst, a foaming agent and a surfactant.

The content of the cork is 13 wt% or less, preferably 12 wt% or less, preferably 11 wt% or less, preferably 10 wt% or less, preferably 9 wt% or less, preferably 8 wt% % Or less, preferably 6 wt% or less, preferably 5 wt% or less.

The cork-polyurethane foam composites produced according to the present invention have a low density of natural cork materials, low conductivity against heat, noise, vibration, high elasticity and resilience, resulting in light weight of rigid polyurethane foam, Mechanical properties such as impact absorption, vibration and acoustic damping, recovery force, strength and rigidity are greatly improved, and the excellent characteristics can be maintained even at a very low temperature.

1 shows a method for producing a cork filled polyurethane foam according to an embodiment of the present invention.
2 is a cross-sectional photograph of a polyurethane foam produced according to an embodiment of the present invention.
3 is an electron micrograph of a polyurethane foam produced according to an embodiment of the present invention.
Fig. 4 shows the storage modulus of the polyurethane foam according to the filling amount of the cork.
Fig. 5 shows the loss elastic modulus of the polyurethane foam according to the filling amount of the cork.
Figure 6 shows the change in the tangent delta value of the polyurethane foam according to the fill amount of the cork.
Figure 7 shows the results of compressive strength testing of polyurethane foam.
8 is an SEM image of a polyurethane foam containing pristine cork.
9 is an SEM image of a polyurethane foam containing cork particles having a particle size of 0 to 100 mu m.
10 is a graph showing a correlation between cell size and density.
Figure 11 shows changes in the values of the compressive modulus and the normalized modulus of the foam depending on the crank fill content.
Fig. 12 shows changes in storage modulus according to the cork particle size, Fig. 13 shows changes in loss modulus with respect to crank particle size, Fig. 14 shows changes in tangent delta with crank particle size, The change of Tg according to the cork particle size is shown.
Various embodiments are now described with reference to the drawings, wherein like reference numerals are used throughout the drawings to refer to like elements. For purposes of explanation, various descriptions are set forth herein to provide an understanding of the present invention. It is evident, however, that such embodiments may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing the embodiments.

The following description provides a simplified description of one or more embodiments in order to provide a basic understanding of embodiments of the invention. This section is not a comprehensive overview of all possible embodiments and is not intended to identify key elements or to cover the scope of all embodiments of all elements. Its sole purpose is to present the concept of one or more embodiments in a simplified form as a prelude to the more detailed description that is presented later.

1 shows a method for producing a cork filled polyurethane foam according to an embodiment of the present invention.

A method of manufacturing a cork filled polyurethane foam according to an embodiment of the present invention includes uniformly dispersing cork powder in a polyol using a pre-confinement method; Removing bubbles generated in the cork-polyol mixture; Adding an additive to the cork-polyol mixture; And mixing and reacting the diisocyanate with the cork-polyol mixture.

1, the cork powder is dispersed in a polyol using a pre-confinement method, the bubbles are removed through a defoaming operation as shown in the next step, the additive is added as seen in the next step, , The diisocyanate is mixed and reacted with the cork-polyol mixture.

The polyol used in the present invention is a polypropylene glycol having a functionality of 2 and having an OH value of 435 to 465 and a molecular weight of 455 g / mol.

Isocyanate is a polymeric MDI having a functional group of 2.3 to 2.7, an NCO content of 30 to 32% and a molecular weight of 350 to 400 g / mol.

The cork powder used in the present invention is a natural cork powder having an average cell size of 10 to 50 μm and a density of 0.1 to 0.2 g / cm ³ .

1,4-Diazabicyclo [2.2.2] octane, an amine catalyst of Sigma-Aldrich, was used as the catalyst. The foaming agent was Alfa Aesar's boiling point of 47-49 ° C Cyclopentane. As the surfactant, a silicone surfactant manufactured by BYK Co., Ltd. was used.

The pre-confinement mixing is performed using a pre-confinement mixing machine. In this case, the revolution speed is 400 to 2000 rpm, the rotation speed is 2.5 times the revolution speed, and the time is 0 to 10 minutes.

2 is a cross-sectional photograph of a polyurethane foam produced according to an embodiment of the present invention.

In FIG. 2, the leftmost part shows the polyurethane foam not containing the cork, the middle part is filled with 5 wt% of the cork powder at the weight ratio of polyurethane, and the rightmost part is the polyurethane foam filled with 10 wt%.

3 is an electron micrograph of a polyurethane foam produced according to an embodiment of the present invention.

In the case of Fig. 3, similarly to Fig. 2, SEM photographs are shown from the leftmost side, in which the cork is not included, the cork is filled with 5 wt% of powder, and the cork powder is filled with 10 wt%.

As shown in FIG. 3, when 5 wt% of the cork powder is filled, the cork powder is naturally inserted into the polyurethane grain structure. However, as shown in the rightmost photograph, when the cork powder is filled at 10 wt% It can be seen that the polyurethane grain structure does not maintain its original shape. Whereby the mechanical properties of the polyurethane foam may be deteriorated.

Table 1 below shows the morphological parameters of cork, polyurethane, polyurethane-cork composite (5 wt%, 10 wt%).

Foam ρ _p (g / cm 3) ρ _f (g / cm 3) d (μm) Nc X 10 ⁴ (cell / cm 3) δ (μm) Cork 0.14 0.14 18.00 17147 3.02 PU 1.10 0.10 482.0 0.8930 48.2 PU / Cork 5 0.82 0.11 86.67 153.60 13.6 PU / Cork 10 0.67 0.13 42.04 1345.9 10.1

ρ _p : pre-foam density

ρ _f : foam density

d: cell diameter

Nc: cell density

δ: cell wall thickness

Meanwhile, according to one embodiment of the present invention, the content of cork is important in weight ratio to polyurethane. This is because the mechanical properties of the polyurethane foam are expected to be improved as the content of the cork powder increases. However, when the amount of the cork powder is more than a certain amount, the mechanical properties of the polyurethane foam deteriorate.

Therefore, the content of cork is preferably 13 wt% or less, preferably 12 wt% or less, more preferably 11 wt% or less, and more preferably 10 wt% or less, by weight relative to polyurethane Is preferably 9 wt% or less, preferably 8 wt% or less, more preferably 7 wt% or less, preferably 6 wt% or less, and more preferably 5 wt% or less.

Fig. 4 shows the storage modulus of the polyurethane foam according to the filling amount of the cork, Fig. 5 shows the loss elastic modulus of the polyurethane foam according to the filling amount of the cork, Fig. The change in the tangent delta value of the polyurethane foam depending on the filling amount of the polyurethane foam.

As shown in FIG. 4, it can be seen that the value of the storage elastic modulus increases as the polyurethane is filled with cork, and as shown in FIG. 5, the value of the loss elastic modulus increases as the polyurethane is filled with cork. As shown in FIG. 6, it can be seen that the tangent delta value, which is the ratio of the loss elastic modulus to the storage elastic modulus, increases as the polyurethane is filled with cork. Also, it can be seen that the glass transition temperature (T _g ) value increases as the polyurethane is filled with cork through the peak.

The results shown in Table 2 below can be obtained by tabulating the contents of FIGS. 4 to 6.

Storage modulus (MPa) at -50 ° C Loss modulus (MPa) at -50 C Tangent Delta at -50 ℃ Tg (占 폚) PU foam 8 0.3 0.037 98 PU / Cork 1wt% 15 0.6 0.040 100 PU / Cork 5wt% 20 One 0.050 103 PU / Cork 10wt% 35 2 0.057 110

Figure 7 shows the results of a compression test of a polyurethane foam. As shown in FIG. 7, a much larger compressive stress is required to produce a constant size deformation when the cork is filled than the 100% polyurethane foam, and thus the mechanical strength is better when the cork is filled.

On the other hand, the change of the physical properties of the polyurethane foam according to the cork particle size was examined, and the results were as follows.

Sieve Size (um) pristine cork 500 400 300 200 100 Average Cork Particle Size (um) 616.0 468.7 359.0 283.3 186.3 75.7

As shown in Table 3, cork polyurethane composite foams were produced according to the cork particle size, and the cork particle sizes were divided into 100 μm, 200 μm, 300 μm, 400 μm and 500 μm pristine cork, and the cork particle size was determined by the mechanical properties of the cork polyurethane foam And the effect on the thermal properties were examined.

8 is an SEM image of a polyurethane foam containing pristine cork. As shown in FIG. 8, when the cork particle size is 0-1 mm, the cell size tends to decrease as the filled cork content increases.

9 is an SEM image of a polyurethane foam containing cork particles having a particle size of 0 to 100 mu m, squeezed with a sieve to pristine cork. As shown in FIG. 9, even when the cork particle size is 0-100 μm, the cell size tends to decrease as the filled cork content increases. Compared to FIG. 8, which is a sample filled with cork particles of 0-1 mm size, It was confirmed that the reduction width was reduced.

10 is a graph showing a correlation between cell size and density. As shown in FIG. 10, the density of the foam increases with decreasing cell size. The reason for the increase of the density of the polyurethane foam depending on the cork content is that the melt viscosity increases as the cork particles are filled, .

Figure 11 shows changes in the values of the compressive modulus and the normalized modulus of the foam depending on the crank fill content. As shown in FIG. 11, the values of the compressive modulus and the normalized modulus of the foam increased with the cork filling amount, and when the cork filled with 0-1 mm was filled with the cork filled with 0-100 μm, the increase of the modulus Respectively.

Storage modulus, loss modulus, tangent delta, and glass transition temperature (Tg) values of cork particle size were measured by DMA test. The results are as follows.

Fig. 12 shows changes in storage modulus according to cork particle size, Fig. 13 shows change in loss modulus according to cork particle size, Fig. 14 shows change in tangent delta according to cork particle size, It shows the change of Tg according to size.

As shown in FIG. 12, the storage modulus of the cork polyurethane foam tends to increase as the cork particle size increases, and as shown in FIG. 13, the loss modulus tends to increase as the cork particle size increases.

Referring to FIG. 14, it was confirmed that the tangent delta value had no significant effect on the cork particle size.

Referring to FIG. 15, the glass transition temperature (Tg) value increased with increasing cork particle size, but decreased with increasing cork size. Tg values tend to increase when filled with cork compared to neat polyurethane foam that is not corked.

The description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features presented herein.

Claims (12)

Uniformly dispersing the cork powder in the polyol using a pre-confocal mixing method;
Removing bubbles generated in the cork-polyol mixture;
Adding an additive to the cork-polyol mixture; And
Mixing and reacting the diisocyanate with the cork-polyol mixture,
A method for producing a cork filled polyurethane foam.
The method according to claim 1,
Wherein the additive comprises a catalyst, a foaming agent and a surfactant.
A method for producing a cork filled polyurethane foam.
The method according to claim 1,
Characterized in that the content of the cork is 13 wt%
A method for producing a cork filled polyurethane foam.
The method according to claim 1,
Wherein the content of the cork is 12 wt% or less.
A method for producing a cork filled polyurethane foam.
The method according to claim 1,
Characterized in that the content of the cork is 11 wt%
A method for producing a cork filled polyurethane foam.
The method according to claim 1,
Wherein the content of the cork is 10 wt% or less.
A method for producing a cork filled polyurethane foam.
The method according to claim 1,
Characterized in that the content of the cork is 9 wt%
A method for producing a cork filled polyurethane foam. The method according to claim 1,
Wherein the content of the cork is 8 wt% or less.
A method for producing a cork filled polyurethane foam. The method according to claim 1,
Wherein the content of the cork is 7 wt% or less.
A method for producing a cork filled polyurethane foam. The method according to claim 1,
Characterized in that the content of the cork is 6 wt%
A method for producing a cork filled polyurethane foam. The method according to claim 1,
Wherein the content of the cork is 5 wt% or less.
A method for producing a cork filled polyurethane foam. Containing less than 10 wt% cork,
Polyurethane foam filled with cork.

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