JPS60171127A - Flattened article made of restoring foamed body - Google Patents

Abstract

PURPOSE:To obtain the flattened article which has small volume and easy handling and moreover may form by heating an independent bubble type-foam stably in dimension and easily, by flattening the composition in which a heat foaming binder has been added into the cavities of an elastomeric foam. CONSTITUTION:First, the cavities 2 of an elastomeric foam 1 are caused to contain a heat foaming binder (e.g. the composition in which the foaming agent such as Azodicarbonamide, etc. is added to polyethylene, etc.). Next ordinarily, while heating and flattening said foam 1, the binder is solidified at the flattened state being kept as it is. The flattened state is kept by the heat foaming binder in the cavities 2, and moreover it may be restored to the original elastomeric foam by heating, and further said binder may be foamed. Thus, the objective article 3 is obtained. EFFECT:The foam excellent in heat insulating and sealing is obtained. It is easily inserted into between the members to be fitted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resilient foam flattened product for forming foams used for the purposes of soundproofing, heat insulation, sealing, etc. in home appliances, automobiles, houses, etc.

Foams have traditionally been used in various industries because they exhibit good properties such as heat insulation, sound insulation, buoyancy, sound absorption, and vibration damping.

However, when assembling the foam as part of a structure, it is bulky and difficult to handle, especially when the foam is attached to a specific part of an already assembled structure. It has the disadvantage that it is difficult to install, as it requires insertion, and workability is poor.

In order to solve the above-mentioned drawbacks, two-component foamable resins and foamable resin sheets have been devised.

The above-mentioned two-component foamable resin is one in which a foaming agent component and a resin component are mixed at the time of use, injected into the area where a foam is to be formed, and then heated and foamed to form a foam. Furthermore, the above-mentioned foamable resin sheet is one in which an unfoamed spacer sheet mixed with a foaming agent is attached to an object to be attached to which a foam is to be formed, and then heated and foamed to form a foam. .

However, with the two-component foamable resin, it is not possible to form a foam of a specific shape in a specific location of a structure, and the foam is formed even in unnecessary parts. Furthermore, in the case of foamable resin sheets, it is difficult to form a foam with good dimensional stability because blurring occurs during heating and foaming, and the foaming pressure varies depending on the heating temperature.

Therefore, as a result of studies in view of the above-mentioned circumstances, the present applicant found that a material capable of solving the above-mentioned drawbacks is a flattened elastic foam containing a bonding agent in the void, and this flattened state We have already proposed a flattened foam that can be restored to its original form by heating. Note that the above-mentioned fixing agent is a resin that softens or melts when heated and can solidify when cooled.

When this flattened product is heated, the above-mentioned fixing agent softens or melts, allowing it to be restored to a re-strung foam with good dimension stability. It is useful as a material that can form foams with good dimensional stability.

However, the foam formed by heating this flattened material has the same cellular state as the above-mentioned elastic foam, that is, an open cell type or an open cell type with some closed cells mixed, and has sound absorption, water absorption, and cushioning properties. Although properties such as elasticity are good, the properties of closed-cell foams, such as heat insulation, buoyancy, soundproofing, and noise insulation, are not sufficient. For this reason,
The above-mentioned flattened product cannot be said to be satisfactory in applications requiring the characteristics of a closed-cell foam.

The reason why the above-mentioned elastic foam is an open-cell type or an open-cell type with some closed cells mixed is that it must be able to contain a fixing agent in its voids and be flattened. It is.

Therefore, the present applicant sought to provide a material that is not bulky, easy to handle, and capable of forming a foam of a specific shape with good dimensional stability, like the flattened product proposed above, and that also allows the foam to be made into a closed-cell type. As a result of intensive studies aimed at this purpose, we have come up with this invention.

That is, the present invention is a flattened product in which an elastic foam containing a heat-foamable fixing agent in the void portion is flattened and this flattened state is maintained by the fixing agent, and the original foaming is performed by heating. This invention relates to a flattened resilient foam that can be restored to the body and the above-mentioned fixing agent can be foamed.

The resilient foam flattened product of the present invention is produced by impregnating the voids 2 of the elastic foam l with a heat-foamable adhesive as shown in FIG. It can be obtained by flattening the elastic foam 1 by compression or the like after being softened or melted by heating at a temperature that does not decompose the foaming agent, and solidifying the fixing agent by cooling or the like in this flattened state. , for example, a flattened product 3 as shown in FIG. 03).

When this flattened product 3 is heated, the above-mentioned fixing agent is softened or melted, and the foamed product shown in FIG. is foamed, and the foamed resin thus formed covers at least a portion of the voids of the restored foam,
Usually it is almost completely filled.

The foam formed from the above-mentioned flattened product has been restored to the original shape of the elastic foam with good dimensional stability, and the original elastic foam is of an open-cell type or partially While it is an open cell type with a mixture of closed cells,
A closed cell type or a closed cell type with some open cells mixed therein can be obtained by adjusting the foamability of the above-mentioned fixing agent.

The flattened resilient foam of this invention is not bulky and convenient to transport, and it also has better punching workability than the original elastic foam, making it easy to form foams with complex shapes. . Furthermore, when forming a foam as part of a structure, it is not bulky and easy to handle, can be easily inserted into a specific location, and can be formed into a foam of a desired shape with good dimensional stability.

Moreover, when the above-mentioned flattened material is used, a closed-cell foam or a closed-cell foam with a mixture of open cells depending on the purpose, that is, a foam with good properties such as heat insulation, buoyancy, sound insulation, noise insulation, heat retention, and sealing properties, can be obtained. can be obtained. Furthermore, a foam having a higher compressive strength than the original elastic foam can be obtained.

In addition, by adjusting the foamability of the above-mentioned fixing agent, the state of the cells in the formed foam can be easily adjusted, so that the foam can be given characteristics suitable for its use.

In addition, the above-mentioned flattened material is more applicable to the attached object than foamed resin sheets because the foam and the adhesive can be appropriately selected and used according to the heat resistance of the attached object to which the foam is attached. The range of is wide.

The elastic foam used in this invention means that the external force disappears when the foam itself is compressed and deformed by an external force, regardless of whether or not the polymer material itself that forms the foam has elasticity. It is acceptable as long as it can be restored to the original state.

As for the foamed state of the elastic foam, an open cell type is preferable because it allows the adhesion agent to be contained in the voids and is easy to flatten, but it is preferable to include the adhesion agent to the extent that the flattened state can be maintained. If possible, closed cells may be present in some portions.

The apparent density of this foam is usually 0.5 or less, with a lower limit of about 0.005 and a more preferable range of 0.02 to 0.3. If this apparent density is too high, even if the foam is flattened, the volume will decrease only slightly, and since there are few voids, it will not be possible to contain the adhesive necessary to maintain the flattened state, which is undesirable. Moreover, if it is too low, the mechanical properties of the foam formed from the flattened product will deteriorate, which is not preferable.

Further, the thickness of the elastic foam is usually preferably 3 or more, more generally about 3 to 100 pieces, but is not limited to this.

The elastic foam described above can be manufactured using various polymers and various known methods.

The polymer used is not particularly limited as long as it can form an elastic foam having the above-mentioned functions.
For example, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyurethane, comb, etc. can be used.

The heat-foamable fixing agent used in this invention is made of a foamable resin composition, which can be melted or softened by heating at a temperature at which the foaming agent contained therein does not decompose, and which solidifies by cooling. When heated above the decomposition temperature of the agent, it can be foamed to form a foamed resin.

The fixing agent must have a melting point or softening point lower than the decomposition temperature of the blowing agent contained therein, and a blowing agent whose decomposition temperature is lower than the melting point or softening point of the elastic foam. .

If the melting point or softening point of the fixing agent is higher than the decomposition temperature of the foaming agent, when the elastic foam is flattened and fixed with the fixing agent, the foaming agent will decompose and the fixation will not be possible, or even if it is fixed, it will not be possible to fix it. However, since the foam formed from this flattened product does not become a closed cell type, the object of the present invention cannot be achieved. Furthermore, if the decomposition temperature of the foaming agent is higher than the melting point or softening point of the elastic foam, when the adhesive foams, the adhesive force is removed and the restored foam loses its shape. The purpose will not be achieved.

Further, the melting point or softening point of the above-mentioned fixing agent is generally 10°C or more higher than room temperature, and the more preferable melting point or softening point is 30 to 180°C. If this melting point or softening point is too low, the flattened foam will return to its foamed state during storage, which is undesirable.If it is too high, it will generally lead to thermal deterioration of the elastic foam and the properties of the restored foam. This is not preferable because it reduces the

The decomposition temperature of the foaming agent contained in this adhesive is usually 10°C or more higher than the melting point or softening point of the adhesive, and usually 10°C or more lower than the melting point or softening point of the elastic foam. is preferable.

This heat-foamable fixing agent is obtained by blending various thermosetting or thermoplastic resins with a blowing agent and, if necessary, a blowing aid, filler, stabilizer, etc. in a manner that satisfies the above conditions. It consists of a foamable resin composition.

Rd is the thermoplastic resin described in °C, which includes polyethylene, ethylene-vinyl acetate copolymer, polypropylene, cellulose acetate butyrate, polyamide resin, polyvinyl chloride, thermoplastic polyester resin, etc.; Examples of the resin include epoxy resin, thermosetting polyester resin, and acrylic resin.

Further, as the foaming agent, azodicarbonamide,
Azo blowing agents such as azobisisobutyronitrile, barium azodicarboxylate, diethyl azodicarboxylate, diazoaminobenzene, azocyclohexylnitrile, p-toluenesulfonylhydrazide, benzenesulfonylhydrazide, p-p'-oxybis Hydrazide blowing agents such as benzenesulfonyl hydrazide, p
・Carbazide blowing agents such as p-oxybisbenzenesulfonyl semicarbazide and p-t-ruenesulfonyl semicarbazide, N-marginitrosopentamethylenetetramine, N-N-dimethyl-N-N'-dinitrosoterephthalic acid amide, etc. Nitroso-based blowing agents, ammonium carbonate, ammonium bicarbonate, ammonium nitrite, and other inorganic blowing agents.

The amount of this foaming agent to be used is determined appropriately so that the foam formed from the flattened resilient foam material will have the desired cellular state, and usually the foaming adhesive is used alone to form the foam. It is preferable that the foamed resin has a foaming ratio of about 2 to 30 times.

In addition, by using a foamable resin composition containing the above-mentioned thermosetting resin and a curing agent as a foaming fixing agent, the flattened resilient foam is heated to return to its original elastic foam shape. After the resin is restored and the adhesive is foamed to form a foamed resin, the foamed resin may be cured. According to this, the hardness and strength of the foam formed from the flattened product can be adjusted. However, as for the above-mentioned curing agent, curing does not proceed at the heating temperature used when flattening the elastic foam, and furthermore, it does not cure at a temperature higher than the decomposition temperature of the foaming agent and may affect the foam shape of the restored foam. Needless to say, use a material that can cure the resin at a temperature that is not high.

In order to incorporate this heat-foamable fixing agent into the voids of the elastic foam, the fixing agent is dissolved in a solvent, the solution is impregnated into the foam, and then the solvent is removed. There are four methods: rubbing the foam into the foam, vibrating the foam to incorporate it, or dipping the foam into a molten adhesive.

The amount of adhesive to be included in the voids of the elastic foam is usually 20% of the total amount of the elastic foam and adhesive.
It is best to maintain the flattened state of the elastic foam by the fixing force from the relationship between the elastic recovery force of the foam and the fixing force of the fixing agent. It is determined as appropriate so that the foam formed from the foam will have the desired cellular state. For example, in the case of a polyurethane foam having an apparent density of 0.02 and a thickness of 10 rum, it is usually about 100 to 800 g/yyt'.

The flattened resilient foam of the present invention can be obtained by flattening an elastic foam containing a heat-foamable adhesive in the voids as described above and allowing the adhesive to maintain this flattened state.

To perform the above-mentioned flattening, a foam containing a heat-foamable fixing agent is heated to a temperature that softens or melts the fixing agent to the extent that it can be fixed, and then the foam is flattened while maintaining this flattened state. Let the fixing agent solidify. The temperature does not necessarily need to be higher than the melting point of the adhesive as long as it can be fixed, and it needs to be at a temperature at which the elastic foam does not soften or melt, and the adhesive does not foam.

A specific method for this flattening is, for example, a method in which an elastic foam containing a heat-foamable adhesive is flattened using a hot press at a temperature near the melting point of the adhesive and then cooled in this flattened state (in this case, (Depending on the temperature of the hot press, a cooling step may not be necessary and it may be sufficient to just take it out of the press.) There are also methods in which the material is flattened using cooling rolls immediately after heating.

The flattened product obtained in this way has a thickness that is usually one-fifteenth to half the thickness of the original foam, and as shown in Figure 2, this flattened product is monster 3
When it is easily inserted between the objects to be attached 4.4' and installed at a predetermined location, it is heated to a temperature near the melting point or Europeanization point of the adhesive, as shown in (+3) in the same figure. It restores to its original foam shape and the above-mentioned fixing agent foams to form a closed-cell foam or a closed-cell foam with some open cells mixed in at a predetermined location on the object 4, 4'. 5 is formed.

Needless to say, the temperature during the heating is set to a temperature at which the foam does not soften or become molten.

Note that an adhesive layer or an adhesive layer may be formed on one or both sides of the flattened object for temporary adhesion of the flattened object to the object to be attached or for adhesion of the restored foam to the object to be attached. You can stay there.

The resilient foam flattened product of this invention can be applied to any application that requires the characteristics of foam, but is particularly applicable to sealing materials, tamping materials, heat insulation materials, flotation materials, sound insulation materials, sound insulation materials, and heat insulation materials. It is useful as materials, packaging materials, etc.

EXAMPLES Below, examples of the present invention will be described in more detail. In addition, in the following, parts mean parts by weight.

Examples Ethylene-vinyl acetate copolymer [Evaflex P-1407 manufactured by Mitsui Polychemical Industries, melting point 66°C (vI
cAT method)) ioo parts and 5 parts of a foaming agent (Hinihole AK#2 manufactured by Hydraulic Chemical Co., Ltd., decomposition temperature 120°C) were mixed to give 60%
A foamable resin ready-made product of mesh pass was obtained.

10-thick urethane foam (prefectural density 0.029/
CRFL, open cell type) was heated and applied as a foamable fixing agent to the entire voids of the foam while vibrating the foam at 150°C. /nt, the foam was heated to 90°C and immediately flattened through a cooling roll to obtain a flattened resilient foam of the present invention having a thickness of 1.0 mm.

When this flattened product was heated at 150°C for 10 minutes,
The foam was restored to its original shape with a thickness of 10 mm, and the voids of the urethane foam were almost completely filled with the foamed resin formed by foaming the adhesive.

When a water absorption test was conducted on the foam thus obtained from the above flattened product, the water absorption of this foam was approximately 10% by weight. For comparison, a similar water absorption test was conducted on the original urethane foam, but due to the open cells, the amount of water absorbed was too large to be worth measuring. In this way, the cell state of the foam obtained from the above-mentioned flattened product is different from that of the original urethane foam, and the proportion of closed cells has significantly increased.
won.

In addition, as shown in Fig. 3 (4) and (13), the above-mentioned flattened material 3 has an opening 6 of 8 lengths, 8 widths, and a length of 5071 cm.
After installing it near the opening 6 of the 1 m rectangular body 7,
When heated at 0°C for 10 minutes, Figure 3 (C).

As shown in (2), the foam 5 was formed in the opening 6 of the rectangular body 7, and the opening 6 was sealed.

When the rectangular parallelepiped with its opening sealed in this manner was immersed in water for about 30 minutes, no water entered the inside of the rectangular parallelepiped, and it was found that the foam had excellent sealing properties.

[Brief explanation of the drawing]

Figure 1 (3) is a cross-sectional view showing the state before flattening of an elastic foam whose voids are impregnated with a heat-foamable adhesive;
1(4) is a cross-sectional view of a flattened resilient foam of the present invention obtained by flattening the elastic foam of FIG. A cross-sectional view showing the state in which it is installed between the two, Figure 2 CB) is shown in Figure 2 (4)
FIG. 3 (5) is a cross-sectional view showing the state in which the flattened product mounted as shown in FIG. A cross-sectional view showing the state in which it is installed, Figure 3 (] 3) is the same as Figure 3 (5) above.
3(C) is a sectional view showing the state in which the flattened material mounted as shown in FIG. 3(A), a3) is heated to form a foam, 3) is a front view from the opening side of the rectangular parallelepiped shown in FIG. 3(C). DESCRIPTION OF SYMBOLS 1... Elastic foam, 2... Voids, 3... Flattened resilient foam, 5... Foam. Patent applicant Nitto Electric Industry Co., Ltd.

Claims (1)

[Claims] (1) A flattened product is obtained by flattening an elastic foam containing a heat-foamable adhesive in the void, and maintaining this flattened state with the adhesive, which restores the original foam shape by heating. A resilient foam flattened product that is capable of being foamed with the above-mentioned fixing agent.