KR810000813B1 - Method of preparing polyisocyamate that has circular foams - Google Patents

Abstract

Polyisocyanate foams prepd. in a mold having a foam height detector and retreatable side walls have isotropic bubbling properties. As X and Y direction of four parts in mold container can be moved freely, bubbles of foam can be transformed into isotropic foams without pressing around foams. So the bubbling pressure of the foams in a mold is lowered to prepare polyurethane foams with isotropic mechanical properties.

Description

Method for producing polyisocyanate-based foam having isotropic foam

1 is a cross-sectional view of the conventional foam in the free rising direction.

2 is a cross-sectional view in the free rising direction of the foam of the present invention.

Figure 3 is a perspective view of the outer mold of the foam container showing an embodiment of the present invention.

4 is a perspective view of an inner mold which is a main part of the present invention.

5 is a perspective view of a bottom plate which is an essential part of the present invention.

6 is a perspective view of the inner mold after the bubble is completed.

7 is a perspective view showing the position of the inner mold before the bubble composition is injected.

8 is a plan view showing the position where the inner mold is placed on the outer mold.

9 is a partial sectional view showing a position where the inner mold and the outer mold are installed just before the injection of the bubble composition.

10, 11 and 12 are each a process chart according to the manufacturing sequence of the present invention.

13 and 14 are perspective views each showing a modification of the mold used in the present invention.

Fig. 15 is a schematic plan view showing a modification of the mold used in the present invention.

The present invention relates to a method and apparatus for producing a polyisocyanate-based foam having isotropic bubbles having uniform physical properties in all directions regardless of bubble direction and stability in specification.

Conventionally, molding methods and apparatuses for polyurethane-based foams are known and have been applied to everyone. Foams molded by these conventional methods and apparatus have, as is well known, oval bubbles typically having long diameters. And the different physical properties of the polyurethanes deforming along the bubble direction are also related to the bubble structure.

Therefore, various studies on the deformation of such a bubble-like structure, that is, a method and apparatus for forming a polyurethane foam into an isotropic bubble-like structure have been conducted. The results are, for example, US Patent No. 3,249,486 and Japanese Patent Application No. 28,781,1973. However, in the method disclosed in the above patent, a cap is placed in the foam container of the foam or a flat plate material is pressed against the upper surface of the foam, thereby forcibly pressing the upper portion of the foam so that the foam extends in the inner wall direction of the container. By forming a bubble and naturally increasing the foaming pressure applied to the entire mold container, it is to solve the problem of the mold container structure and the problem of mold removal.

It is an object of the present invention to provide a novel method and apparatus for producing a polyisocyanate foam in which the bubble structure is particularly improved with isotropic bubbles. According to the present invention, the foam can be produced by a simple lightweight mold container for short mold removal. It is possible to make the foam expand in any direction and to expand the bubble in one direction according to the rising height or the foaming speed or the operation of the detection device when expanding at a predetermined position without placing the holding plate on the upper portion of the foam. By expanding the mold so that it expands in two directions (hereinafter referred to as XX and YY directions) so that all are perpendicular to the above-mentioned free rising direction, thereby freeing the bubble structure. Can be changed to

As used herein, the term “polyisocyanate foam” refers to isocyanate foam, polycarbodiimide foam, or the like as a base material of a foam product. However, the present invention mainly describes the polyurethane foam.

According to the present invention, the polyurethane foam having an isotropic bubble can be produced by developing the mold in the X and Y directions, and the present invention will be described in more detail as follows. In general, the polyurethane foam can be prepared by the following method irrespective of the rigidity or the radius, that is, when the foam composition is mixed and stirred, bubbles are formed in the cream state within a few seconds to several minutes. The gradual increase in viscosity leads to a so-called non-moving state, and when such a state is reached, the foam does not stick any more in minutes to several tens of minutes even after touching the surface of the foam, and then the bubble process is completed within a few seconds to several minutes. . In this case, the foaming of the foam is measured at the time when the foam is not moved from the cream state, but the volume of the foam is increased only a few%, so even when the foam is made from the state without moving the finished product is not affected much.

For this reason, in the present invention, it is important to change the foaming of the foam when the foam composition has fluidity before the foam composition is in a non-moving state, and for this purpose, the four X and Y directions of the mold container are freely changed. The foam bubbles are deformed so that little pressure is applied around the foam forming the bubbles. In this case, since the upper part of the mold container is open and the foaming agent has fluidity as described above, the bubble pressure of the foam is very low, which is half of the foam composition.

As a result, the polyurethane foam formed from the isotropic bubbles can be easily produced by making four places of the mold almost free with a simple jig. As described above, the foam having the isotropic foam produced by the present invention has almost the same appearance as the foam produced by the conventional method, but has better physical properties and can be produced in a very short time, thereby improving production efficiency.

The foam produced by the present invention has a good stability on the specification, and thus can significantly reduce the specific gravity of the foam according to the purpose of use. Therefore, the specific gravity can be reduced and the mold removal time can be shortened, thereby greatly reducing the manufacturing cost. In this specification, the motivation for producing the foam of the foam in the form of almost completely isotropic foam is based on the reason that the foaming process, i.e., foaming can be performed by appropriately adjusting both foaming directions in the longitudinal direction as well as in the axial direction. As a result, they found an effective means for this.

The present invention will be described in detail with reference to the accompanying drawings. In a suitable embodiment of the present invention as described below, a double mold is shown which is used in addition to the essential mold of the present invention, but the outer mold is not essential in the present invention. However, the use of an external mold also belongs to the present invention as well.

As shown in FIG. 1, the normal bubble shape is elliptical having a major axis in the Z direction because the expansion is insufficient in the X and Y directions compared to the Z direction.

Figure 2 shows the shape of the isotropic bubbles of the foam produced according to the invention, in this case the same level of expansion in the X and Y directions.

FIG. 3 shows an example of the outer mold A, and FIG. 4 shows an example of the essential mold B of the present invention. (Hereinafter referred to as an inner mold), reference numeral 3 in FIG. 4 denotes a side wall, and reference numeral 4 in FIG. 5 denotes a bottom plate. The outer mold (A) is formed so that the side plate (1) can be opened outward, for example in the direction of the arrow in the drawing, the inner mold (B) can be easily placed and removed inside the outer mold (roller) Conveyor 2 is installed.

On the other hand, the inner mold B is formed of a body having a side wall 3 and a bottom plate 4, the side wall 3 is collapsible and collapsible as shown in FIG. 4, and the bottom plate 4 protrudes. Has a grating 5. This grating 5 coincides with the cleaved bottom when the body is folded and shrunk. That is, it will be in the state of FIG. 7 so that a bubble composition may not leak. In the case of the collapsed structure of the main body, each side wall is fixed to the hinge 7 as shown in FIG.

In FIG. 6, reference numeral 8 denotes a metal mechanism capable of dismantling the side wall 7 of the inner mold B after the bubble process is completed and removing it from the manufactured foam.

When the inner mold B having such a structure is placed on the outer mold A, the inner mold B is folded and reduced in the state shown in FIG. In the state where the inner mold is placed on the outer mold, as shown in FIG. 8, a space (a) is formed for injecting and holding the bubble composition in the central portion, and a space (b) having a distance indicated therein in the direction of the arrow in the figure. ) Is formed, which is necessary to make the foam bubbles isotropic. In this connection, from the standpoint of the formation of isotropic bubbles and the cleavage and contraction of the inner mold B, the central space a is represented by 1 / 3-1 / 4 of the space area as shown in FIG. It is desirable and suitable to have an area.

FIG. 9 shows the structure of the apparatus for performing bubble operation using both the outer mold A and the inner mold B described above. Here, the cushion material 9 has a thickness of about 5-10 mm and is preliminarily adhered to the bottom plate 4, and the lattice 5 is fixed on the bottom plate 4. The mold removal paper 10 is covered on the side wall 3 and the bottom plate 4 to facilitate the repeated use of the inner mold B. Suitable materials for use as the side wall 3 and the bottom plate 4 include, for example, metal plates having the same strength as plywood having a thickness of about 15 mm. The thickness of the grating 5 is enough to be about 5 mm.

In addition, as shown in FIG. 9, the retaining plate 12 'is installed in contact with the outside of the side wall 3 of the inner mold B, and the mold developing means 12 is operated to open the inner mold B in the cleavage direction. It tells you the time to deploy and move. The mold deployment means 12 is fixed through the side of the outer mold A as shown in the figure, but the outer mold A is only an auxiliary frame capable of supporting the mold deployment means.

This means can also be used for hydraulic systems or screw systems. The action of the mold deployment means 12 is connected to a contact detection height detection means 11, such as a limit switch. The height detecting means is used to detect the height of the foam surface arranged at a specific position on the injection space a, and by its action the side 3 is cleaved and not folded outwards, ie in the X and Y directions. The detection means 11 is connected to the mold deployment means 12 and the mold deployment means 12 serves to automatically deploy the inner mold B, and the inner mold B is pivotally rotated or not. It is desirable to design it to move up and down so that the foam can be removed immediately after curing.

The method of the present invention is achieved by using the outer mold (A) and the inner mold (B) thus designed.

The present invention will be described in more detail with reference to the production of polyurethane-based foams having isotropic bubbles as follows. First, as shown in FIG. 10, the polyurethane-based foam composition is mixed, stirred, and injected into the space (a) in an amount sufficient to fill the space of the final volume as shown in FIG. The composition then begins to foam in the cream.

The foam begins to expand to the height of the detection means 11, such as the limit switch located above the space a. This step is not particularly different from conventional foam formulations and the bubbles thus formed are elliptical, where the liquid composition is fluid.

As shown in FIG. 11, when the foam is expanded to the height of the detecting means 11, the mold deploying means 12 moves outwards, whereby the side wall 3 of the inner mold B is cleaved. Since the height of the foam is detected by the detecting means 11 and held uniformly at this time, since the foam is pre-foamed in the Z direction, the bubble is in the X and Y directions as indicated by the arc. At the same time the bubbles of the foam begin to form isotropically.

Foaming in the X and Y directions continues until the side wall 3 is in the state of FIG. 6 (compare FIG. 12). Thus, when the foam visually identifies its appearance and no longer foams, the foam is removed from the mold as a final product.

Thus, according to the present invention, the foam product is obtained as a foam having almost uniform isotropic bubbles in all directions and having uniform physical properties since continuous foaming in X and directions is caused by automatic operation of the mold spreading means connected to the height detecting means. Can lose.

Moreover, since the foaming pressure is difficult to apply to the foam itself from the side, the mold removal time of the foam can be significantly shortened. In this regard, conventional foams are broken when the foams are removed from the molds due to internal stresses on the foam sides if they are not left in the mold containers for 20-60 minutes at room temperature after the foaming process.

In contrast, according to the present invention, even if the mold is removed within one or two minutes after the foaming is completed, the foam does not break. Therefore, the number of foam containers required in the present invention can be reduced to 1/10 or less than the number of containers in the conventional method, which is an advantage of the present invention.

As a mold for use in the apparatus of the present invention, molds other than those shown in Figs. 4 and 8, such as molds having bellow sidewalls (see Figs. 13 and 14) or molds which can be folded at four corners ( (See also FIG. 15). In this case, it is preferable to install the mold deployment means at four corners, and this method, as indicated by lines 21 and 23, injects the foam composition into the mold when the mold is contracted, and then in the Z direction. According to the operation of the height detecting means 11 (not shown), the mold can be developed to a desired position in the X and Y directions (indicated by lines 22 and 24) to thereby obtain a polyurethane foam having isotropic bubbles. have.

The present invention will be described in detail by way of examples.

Example 1

First, five bubble compositions (조 A ＂) were prepared according to the following prescription.

Next, 130 parts of a prepolymer (sucrose polyether isocyanate) was added to each of the XA solutions, and each mixture was mixed to prepare five kinds of polyurethane foams having different specific gravity. Comparative results of the physical properties of the five polyurethane foams thus prepared are shown in Table 1 below. In Table 1, No. 1 is a polyurethane foam prepared by a conventional method, and No. 2-No. 5 is a polyurethane foam prepared according to the present invention. The foam for the sample is 500 × 1000 × 2000 mm.

TABLE 1

Example 2

First, the composition solution was prepared according to the following prescription.

30 parts of polyether (aromatic series: OH level 380)

70 parts of polyether (sucrose series: OH value 450)

Next, 162 parts of a prepolymer (suscrose-polyether isocyanate) was mixed and stirred in the composition solution to prepare a polyurethane foam according to the conventional method and the method of the present invention. Comparative results of the physical properties of the two polyurethane foams thus prepared are shown in Table 2 below.

TABLE 2

As can be seen from Tables 1 and 2 above, the polyurethane foams produced by the present invention have almost identical physical properties in both the Z and X and Y directions than those produced by conventional methods. Has That is, according to this invention, it turns out that the polyurethane foam which has an isotropic bubble can be obtained.

Embodiments 1 and 2 describe a method for producing a polyurethane foam having isotropic bubbles by deploying the mold in the X and Y directions according to a detection means that works only when the foam rises to a specific height in the direction.

As described above, the present invention consists in developing the mold in the X and Y directions according to the free rising height in the Z direction, without resorting to the foaming pressure as in the conventional method. It is also an object of the present invention can be achieved by actively operating the mold deployment means in accordance with the foaming rate of the foam composition. According to the modification of the present invention in detail as follows.

For example, the mold deployment means may be activated in accordance with the elevation height detecting means which starts at the same time as the initiation of the expansion or begins shortly after the initiation of the expansion. In this case, unlike the above, the detection means rises when the foam expands to a predetermined height in the Z direction, and thus the mold development means is activated. The detection means stops climbing after reaching a predetermined height in the direction. When the above-described height detecting means 11 is in contact with the foam surface, it is possible to keep the mold developing means 12 in operation. The sidewall 13 of the mold may also be left slightly curved inward rather than completely cleaved at the final point of expansion, as shown in FIG.

Moreover, the mold deploying means can be operated independently after the expansion is started under the conditions measured on the basis of the preliminary test according to the elevation height in the Z direction, and all can be operated by the program control system as necessary. This method is inferior in accuracy to that described above, but the mold deployment means operates by directly detecting the elevation in the Z direction. Appropriate control of the environmental temperature, humidity and the quality of the bubble composition can provide the desired bubble structure.

The foams produced according to the invention have a low density and have a metered physical property, in particular a high degree of specification stability. Therefore, the foam produced according to the present invention is suitable as an insulating material, and it is possible to economically perform all-round construction. In addition, the foam may take the form of an insulating material such as a plate, a cube, a round arc, or the like, and other surface materials such as paper, plastic sheet, plywood, asbestos, metal foil layer, etc. may be laminated on at least one surface of the foam. The finished product thus obtained is thus very useful and widely used in the insulation industry.

Claims (1)

As described above in the text and as shown in the drawings, when the bubble composition expands at a predetermined position, the bubble expands in one or two directions depending on the rising height or the foaming speed so that all of these directions are perpendicular to the free rising direction. A method for producing a polyisocyanate-based foam having an isotropic bubble, characterized in that the bubble is developed so as to form a bubble.

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